KR101996966B1 - Wireless Power Transfer System and Operating method thereof - Google Patents

Abstract

A method of wirelessly transmitting power from a transmitter to a receiver, the method comprising: transmitting a signal for detection of the receiver, receiving an identification packet from the receiver, based on the identification packet of the receiver Resetting a range of a driving frequency of the power transmitter; and transmitting wireless power generated within the range of the reset driving frequency.

Description

Radio power transmission system and its driving method. {Wireless Power Transfer System and Operating method eg}

The present invention relates to a radio power transmission system and a driving method thereof.

Generally, various electronic devices have a battery and are driven by using the electric power charged in the battery. At this time, in the electronic device, the battery may be replaced and may be charged again. To this end, the electronic device has a contact terminal for contacting an external charging device. In other words, the electronic device is electrically connected to the charging device through the contact terminal. However, as the contact terminals are exposed to the outside in the electronic device, they may be contaminated by foreign matter or shorted by moisture. In this case, a poor contact occurs between the contact terminal and the charging device, so that the battery is not charged in the electronic device.

In order to solve the above problem, a wireless power transfer (WPT) for wirelessly charging an electronic device has been proposed.

The wireless power transmission system is a technology that delivers power without space through a space, and maximizes the convenience of power supply to mobile devices and digital home appliances.

The wireless power transmission system has strengths such as saving energy through real-time power usage control, overcoming space constraints in power supply, and reducing waste battery emissions by recharging batteries.

Representative methods of the wireless power transmission system include a magnetic induction method and a magnetic resonance method. The magnetic induction method is a non-contact energy transmission technology in which two coils are brought close to each other, current flows through one coil, and electromotive force is generated in the other coil through the magnetic flux generated. Therefore, a frequency of several hundred kHz can be used. The magnetic resonance method is a magnetic resonance technique using only an electric field or a magnetic field without using an electromagnetic wave or a current, and the power transmission distance is several meters or more, and thus a band of several MHz may be used.

The wireless power transmission system includes a transmitter for wirelessly transmitting power and a receiver for receiving power and charging a load such as a battery. At this time, a charging method of the receiving apparatus, that is, any one of a magnetic induction method and a magnetic resonance method may be selected, and a transmitting apparatus capable of wirelessly transmitting power corresponding to the charging method of the receiving apparatus has been developed.

On the other hand, if the receiver disposed in the charging area of the transmitter is intentionally shaken, or if the receiver shakes frequently, such as a car, the coupling device may suddenly change due to a misalignment between the transceivers. There has been a problem of damaging the receiving apparatus due to the sudden change in the transmission power.

As such, when excessive transmission power is transmitted due to a sudden change in the transmission power, there is a problem in that overvoltage is applied to the reception coil of the receiver. The receiver has a function to provide feedback to reduce the transmit power to the transmitter in order to prevent overvoltage, or has a clamp capacitor on its own to discharge the overcurrent due to excessive transmit power, but according to the excess transmit power The receiver is already damaged before providing feedback, or clamp capacitors alone are limited in dealing with instantaneous rapidly changing overcurrents.

The embodiment can provide a wireless power transmission system and a driving method thereof capable of resolving instability of power transmission due to a sudden change in a coupling coefficient between a transmitter and a receiver due to shaking of a receiver that is being wirelessly charged.

According to an embodiment, there is provided a method of transmitting power wirelessly from a transmitter to a receiver, comprising: transmitting a signal for detection of the receiver; Receiving an identification packet from the receiving device; Resetting a range of a driving frequency of the transmitter based on the identification packet of the receiver; And transmitting the wireless power generated within the range of the reset driving frequency.

In the power transmission method according to the embodiment, resetting the range of the driving frequency may provide a power transmission method for resetting the minimum frequency and the maximum frequency of the driving frequency.

In the power transmission method according to the embodiment, the range of the driving frequency may provide a power transmission method is reset based on the current threshold value of the receiving coil portion included in the identification packet.

In the power transmission method according to the embodiment, the range of the driving frequency may provide a power transmission method that is reset based on the identification packet after receiving a control error packet from the receiver.

In the power transmission method according to the embodiment, the minimum frequency of the reset driving frequency may provide a power transmission method larger than the minimum frequency of the preset driving frequency of the transmitter.

In the power transmission method according to the embodiment, the maximum frequency of the reset driving frequency may provide a power transmission method smaller than the maximum frequency of the preset driving frequency of the transmitter.

In the power transmission method according to an embodiment, Receiving a control error packet from the receiving device; And generating wireless power based on the information on the required power amount of the receiving device of the control error packet.

In the power transmission method according to the embodiment, the step of generating the wireless power, to provide a power transmission method for generating wireless power based on proportional control, integral control and proportional integral differential control (PID control). It may be.

In the power transmission method according to the embodiment, the current control variable according to the previous control error packet is set to the current control variable based on the difference value of the product of the current PID control amount according to the current control error packet and the scaling factor and set the current control variable to the current control variable. A power transmission method for generating wireless power based on this may be provided.

In the power transmission method according to the embodiment, the scaling factor may provide a power transmission method that is changed based on the reset range of the driving frequency.

According to an aspect of an exemplary embodiment, there is provided a method of receiving power by a receiver wirelessly receiving power from a transmitter, the method comprising: transmitting a response signal to a detection signal from the transmitter; Transmitting an identification packet to the transmitter; And receiving wireless power generated according to a range of a reset driving frequency based on the identification packet.

In the power receiving method according to the embodiment, the identification packet may include a current threshold value of the receiving device, and based on the current threshold value may provide a power receiving method in which the range of the driving frequency is reset.

In the power receiving method according to the embodiment, it is possible to provide a power receiving method in which the range of the driving frequency is reset by resetting the minimum frequency and the maximum frequency of the driving frequency.

In the power receiving method according to the embodiment, the minimum frequency of the reset driving frequency may provide a power transmission method larger than the minimum frequency of the preset driving frequency of the transmitter.

In the power receiving method according to the embodiment, the maximum frequency of the reset driving frequency may provide a power transmission method smaller than the maximum frequency of the preset driving frequency of the transmitter.

In the power receiving method according to the embodiment, Comparing the received wireless power and the required power; And transmitting a control error packet to the transmitter according to the comparison result, wherein the control error value is any one of positive, zero, or negative, and the power increase request signal corresponds to a positive control error value. The power retention request signal may correspond to a zero control error value, and the power reduction request signal may provide a power reception method corresponding to a negative control error value.

In one embodiment, a transmission device includes: a transmission coil for wireless power transmission; A power converter for outputting power to the transmitting coil; A control unit controlling the power conversion unit to control the amount of power output to the transmission coil; The controller may provide a transmitter for resetting a range of a driving frequency of the power converter based on an identification packet of a receiver that receives the wireless power.

In the transmitter according to the embodiment, the identification packet may include a current threshold value of the receiver, and may provide a transmitter for resetting the range of the driving frequency based on the current threshold value.

In the transmission apparatus according to the embodiment, the power conversion unit may provide a transmission apparatus that operates either a half bridge inverter or a full bridge inverter based on the identification packet.

In the transmission apparatus according to the embodiment, the control unit, the transmission to control the amount of the wireless power by adjusting any one of a driving frequency, an input voltage, a duty cycle and a phase shift of the power converter. It is also possible to provide a device.

In a transmitting apparatus according to an embodiment, the control unit may include a first calculating unit determining a second current based on a power increase request signal from the receiving device and a first current of the transmission coil; A PID control unit for determining a control amount based on proportional control, integral control, and differential control (hereinafter, referred to as PID control); And a second calculator configured to determine a current control variable based on the control amount and a previous control variable, and may provide a transmitter for controlling the power converter based on the current control variable.

In the transmitter according to the embodiment, the second calculator may provide a transmitter that determines the current control variable based on a value obtained by multiplying the control amount by a scaling factor and a difference value of the previous control variable.

In the transmission apparatus according to the embodiment, the scaling factor may provide a transmission apparatus that is changed based on the reset range of the driving frequency.

A receiving apparatus according to an embodiment includes a control unit for transmitting an identification packet by communicating with the transmitting apparatus; And a receiving coil configured to receive wireless power generated according to a range of a reset driving frequency based on the identification packet.

The receiver according to the embodiment may provide a receiver in which the identification packet includes a current threshold value of the receiver, and the range of the driving frequency is reset based on the current threshold value.

The receiving apparatus according to the embodiment may provide a receiving apparatus in which the range of the driving frequency is reset by resetting the minimum frequency and the maximum frequency of the driving frequency.

In the receiver according to the embodiment, the minimum frequency of the reset driving frequency is greater than the minimum frequency of the preset driving frequency of the transmitter, the maximum frequency of the reset driving frequency is the maximum of the preset driving frequency of the transmitter It is also possible to provide a receiver smaller than frequency.

The embodiment can prevent the power transmission instability, the heat generation, and the system damage of the receiver due to the sudden change in the coupling coefficient between the transmitter and the receiver due to the shaking of the receiver during wireless charging.

1 is a magnetic induction equivalent circuit.
2 is a self resonance equivalent circuit.
3A and 3B are block diagrams illustrating a transmitter as one of sub-systems constituting a wireless power transmission system.
3c is a detailed circuit diagram of a transmission-side power conversion unit according to the embodiment;
4A and 4B are block diagrams illustrating a receiver as one of sub-systems constituting a wireless power transmission system.
5 is a flowchart illustrating an operation of a wireless power transmission system, with an operation flowchart centering on an operating state of a transmitter according to an embodiment.
6 is a graph illustrating a driving state of a power converter according to a load of a receiver;
7 is a flowchart of a method for determining a required power of a receiving device.
8 is a graph showing the magnitude of the coil current on the transmitting-side coil unit according to the driving frequency.
9 and 10 are operation flowcharts of the transmitter including the driving frequency threshold setting step.
11 is a detailed view of a control unit of a transmitter for a power transmission control method.
12 is a timing diagram of a transmitter in a power transmission state;

Hereinafter, a wireless power transmission system including a transmission device having a function of transmitting power wirelessly and a receiving device receiving power wirelessly according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like numbers refer to like elements throughout the specification.

The embodiment selectively uses various types of frequency bands from low frequency (50 kHz) to high frequency (15 MHz) for wireless power transmission, and may include a communication system capable of exchanging data and control signals for system control. .

The embodiment can be applied to various industrial fields such as a mobile terminal industry, a smart watch industry, a computer and laptop industry, a home appliance industry, an electric vehicle industry, a medical device industry, and a robotics industry that use a battery or use electronic devices. .

Embodiments may consider a system capable of transmitting power to one or more devices using one or more transmission coils.

According to an embodiment, a battery shortage problem may be solved in a mobile device such as a smart phone or a notebook. For example, if a wireless charging pad is placed on a table and a smart phone or a notebook is used thereon, the battery is automatically charged and thus can be used for a long time. . In addition, if a wireless charging pad is installed in public places such as cafes, airports, taxis, offices, restaurants, and the like, it is possible to charge various mobile devices regardless of different charging terminals for each mobile device manufacturer. In addition, when wireless power transmission technology is applied to household appliances such as vacuum cleaners and fans, there is no need to search for power cables, and complicated wires disappear in the home, which reduces wiring in the building and expands space utilization. In addition, it takes a lot of time to charge an electric vehicle with the current home power, but if it transmits high power through wireless power transmission technology, it can reduce the charging time and install a wireless charging facility on the floor of the parking lot. It can alleviate the inconvenience of having to prepare.

Terms and abbreviations used in the examples are as follows.

Wireless Power Transfer System: A system that provides wireless power transfer within the magnetic field

Transmitter (Wireless Power Transfer System-Charger; Power Transfer Unit (PTU)): A device that provides wireless power transmission to a power receiver in a magnetic field area and manages the entire system, and may be referred to as a transmitter or a transmitter.

Receiver (Power Receiver Unit: PRU): A device that receives wireless power transmission from a power transmitter in a magnetic field region and may be referred to as a receiver or a receiver.

Charging Area: The area where the actual wireless power transmission takes place in the magnetic field area, and can vary according to the size of the application, required power, and operating frequency.

S parameter: S parameter is a ratio of input voltage to output voltage in the frequency distribution, which is determined by the ratio of input port to output port (S21) or its own reflection of each input / output port, ie its own input. The value of the reflected return (Reflection; S11, S22).

Quality index Q (Quality factor): In resonance, the value of Q means the quality of frequency selection. The higher the value of Q, the better the resonance characteristics. The Q value is expressed as the ratio of energy stored in the resonator to energy lost.

Looking at the principle of transmitting power wirelessly, there are largely a magnetic induction method and a magnetic resonance method as a wireless power transmission principle.

The magnetic induction method is a non-contact energy transmission technology in which electromotive force is generated in the load inductor Ll through the magnetic flux generated when the source inductor Ls and the load inductor Ll are close to each other and current flows through one source inductor Ls. to be. The magnetic resonance method combines two resonators and transmits energy wirelessly by using a resonance technique that generates electric and magnetic fields in the same wavelength range while vibrating at the same frequency due to magnetic resonance caused by natural frequencies between the two resonators. It is a technique to do.

1 is a magnetic induction equivalent circuit.

Referring to FIG. 1, in a magnetic induction equivalent circuit, a transmitter performs magnetic coupling with a source voltage (Vs), a source resistor (Rs), a source capacitor (Cs) for impedance matching, and a receiver according to a device for supplying power. It can be implemented as a source coil (Ls) for the receiver, the receiver is implemented as a load resistance (Rl), the equivalent resistance of the receiver, a load capacitor (Cl) for impedance matching and a load coil (Ll) for magnetic coupling with the transmitter The magnetic coupling degree of the source coil Ls and the load coil Ll may be represented by mutual inductance Msl.

In FIG. 1, when the ratio of input voltage to output voltage (S21) is obtained from a magnetic induction equivalent circuit consisting of only a coil having no source capacitor Cs and a load capacitor Cl for impedance matching, the maximum power transfer condition is found therefrom. The power transfer condition satisfies Equation 1 below.

Equation 1

Ls / Rs = Ll / Rl

According to Equation 1, when the ratio of the inductance of the transmitting coil (Ls) and the source resistance (Rs) and the ratio of the inductance of the load coil (Ll) and the load resistance (Rl) is the maximum power transmission is possible. In systems with only inductance, there is no capacitor to compensate for reactance, so at the point of maximum power transfer, the self-reflection value (S11) of the input / output port cannot be zero, and the mutual inductance ( The power transfer efficiency may vary greatly depending on the Msl) value. Thus, as a compensation capacitor for impedance matching, the source capacitor Cs may be added to the transmitter and the load capacitor Cl may be added to the receiver. The compensation capacitors Cs and Cl may be connected to each of the receiving coil Ls and the load coil Ll in series or in parallel. In addition, passive elements such as additional capacitors and inductors may be further added to each of the transmitter and the receiver for impedance matching.

2 is a self-resonant equivalent circuit.

Referring to FIG. 2, in a self-resonant equivalent circuit, a transmitter includes a source coil and a transmitter-side resonant inductor constituting a closed circuit in series connection of a source voltage Vs, a source resistor Rs, and a source inductor Ls. (L1) and the transmitting side resonant capacitor (C1) in series connection of the resonant coil (Resonant coil) constituting a closed circuit is implemented, the receiver is connected to the load resistor (Rl) and load inductor (Ll) in series connection A load coil, a receiving side resonant inductor L2, and a receiving side resonant inductor L2 and a receiving side resonant capacitor C2 are implemented as a receiving side resonant coil constituting a closed circuit, and a source inductor Ls and a transmitting side inductor ( L1) is magnetically coupled with the coupling coefficient of K01, and the load inductor Ll and the load-side resonant inductor L2 are magnetically coupled with the coupling coefficient of K23, and the transmitting-side resonant inductor L1 and the receiving-side resonant inductor (L2) is magnetically determined by the coupling coefficient of K12 Sums up. In the equivalent circuit of another embodiment, the source coil and / or the load coil may be omitted, and may include only the transmitting side resonance coil and the receiving side resonance coil.

In the self-resonant method, when the resonant frequencies of the two resonators are the same, most of the energy of the resonator of the transmitter may be transferred to the resonator of the receiver, thereby improving power transmission efficiency. The efficiency of the self-resonant method may satisfy Equation 2 below. When it gets better.

Equation 2

k / Γ >> 1 (k is the coupling coefficient, Γ attenuation rate)

In order to increase the efficiency in the self-resonance method, an element for impedance matching may be added, and the impedance matching element may be a passive element such as an inductor and a capacitor.

Based on the wireless power transmission principle, a wireless power transmission system for delivering power in a magnetic induction method or a magnetic resonance method will be described.

<Transmitter>

3A and 3B are block diagrams illustrating a transmitter as one of sub-systems constituting a wireless power transmission system. 3C is a detailed circuit diagram of a transmission-side power converter according to an embodiment.

Referring to FIG. 3A, the wireless power transmission system according to the embodiment may include a transmitter 1000 and a receiver 2000 that receives power wirelessly from the transmitter 1000. The transmitter 1000 generates and charges a magnetic field based on an AC signal output from the transmitter side power converter 101 and an AC signal output from the transmitter side power converter 101, which converts an input AC signal into an AC signal. Controlling the power conversion of the transmission-side resonant circuit section 102 and the transmission-side power conversion section 101 which supplies power to the receiving section 2000 in the area, and the amplitude of the output signal of the transmission-side power conversion section 101 and Adjusts a frequency, performs impedance matching of the transmission side resonant circuit unit 102, senses impedance, voltage, and current information from the transmission side power conversion unit 101 and the transmission side resonant circuit unit 102, and The transmitter side control unit 103 may wirelessly communicate with the receiver 2000. The transmitting power converter 101 may include at least one of a power converter for converting an AC signal into a direct current, a power converter for outputting a direct current by varying the level of the direct current, and a power converter for converting a direct current into an alternating current. Can be. The transmission-side resonant circuit unit 102 may include a coil and an impedance matching unit that may resonate with the coil. In addition, the transmitting side controller 103 may include a sensing unit and a wireless communication unit for sensing impedance, voltage, and current information.

 In addition, referring to FIG. 3B, the transmitter 1000 includes a transmitter AC / DC converter 1100, a transmitter DC / AC converter 1200, a transmitter impedance matcher 1300, and a transmitter coil 1400. And a transmitter-side communication and a controller 1500.

The transmission-side AC / DC converter 1100 is a power converter that converts an AC signal provided from the outside into a DC signal under the control of the transmission-side communication and the controller 1500, and the transmission-side AC / DC converter 1100. The sub system may include a rectifier 1110 and a transmitter DC / DC converter 1120. The rectifier 1110 is a system for converting an provided AC signal into a DC signal. The rectifier 1110 is a diode rectifier having a relatively high efficiency at high frequency operation, a synchronous rectifier or a one-chip capable synchronous rectifier, or a cost. And a hybrid rectifier capable of saving space and having a high degree of dead time. However, the present invention is not limited thereto, and any system that converts AC into DC may be applicable. In addition, the transmitter DC / DC converter 1120 adjusts the level of the DC signal provided from the rectifier 1110 under the control of the transmitter-side communication and the control unit 1500. It may be a buck converter, a boost converter that raises the level of the input signal, a buck boost converter or a coke converter that lowers or raises the level of the input signal. In addition, the DC-to-DC converter 1120 of the transmitting side includes a switch element having a power conversion control function, an inductor and a capacitor having a power conversion mediating function or an output voltage smoothing function, and a voltage gain adjusting or electrical separation function (isolating function). It may include a transformer, etc., and may function to remove the ripple component or pulsation component (AC component included in the DC signal) included in the input DC signal. In addition, an error between the command value of the output signal of the transmitting side DC / DC converter 1120 and the actual output value may be adjusted through a feedback method, which may be performed by the transmitting side communication and the control unit 1500. .

The transmitter DC / AC converter 1200 converts a DC signal output from the transmitter AC / DC converter 1100 into an AC signal under the control of the transmitter-side communication and the control unit 1500, and converts the frequency of the converted AC signal. An example of implementing the system is a half bridge inverter or a full bridge inverter. In the wireless power transmission system, various amplifiers for converting direct current into alternating current may be applied. Examples include class A, B, AB, C, and E class F amplifiers. In addition, the transmitter DC / AC converter 1200 may include an oscillator for generating a frequency of the output signal and a power amplifier for amplifying the output signal.

In addition, the transmission-side power converter 101 of FIG. 3A or the transmission-side DC / AC converter 1200 of FIG. 3B is a half bridge inverter according to the control of the first to fourth switching elements Q1 to Q4 as shown in FIG. 3C. Alternatively, it can be driven by a full bridge inverter.

For example, the first switching element Q1 maintains turn off. The fourth switching element Q4 may be driven by a half bridge inverter by turning on and turning off the second and third switching elements Q2 and Q3 while maintaining the turn-on state. The switching elements Q12 and Q4 may be driven by a full bridge inverter by controlling the turning on and off.

Transmission side direct current according to an embodiment. The AC converter 1200 may alternately drive the second and third switching elements Q2 and Q3 in the half bridge inverter driving state, and the first and fourth switching elements Q1 and Q4 in the full bridge interlock driving state. ) And the second and third switching elements Q2 and Q3 may be alternately driven.

In addition, the first to fourth switching elements Q1 to Q4 may be transistors.

The AC / DC converter 1100 and the transmitter DC / AC converter 1200 may be replaced with an AC power supply, and may be omitted or replaced with another configuration.

The transmission impedance matching unit 1300 minimizes the reflected waves at points having different impedances to improve signal flow. Since the two coils of the transmitter 1000 and the receiver 2000 are spatially separated, there is much leakage of the magnetic field, thereby improving the power transmission efficiency by correcting the impedance difference between the two connection terminals of the transmitter 1000 and the receiver 2000. You can. The transmitter impedance matching unit 1300 may be configured of at least one of an inductor, a capacitor, and a resistor. The impedance may be changed by varying the inductance of the inductor, the capacitance of the capacitor, and the resistance of the resistor under the control of the communication and control unit 1500. You can adjust the impedance value for matching. When the wireless power transmission system transmits power in a magnetic induction manner, the transmission impedance matching unit 1300 may have a series resonance structure or a parallel resonance structure, and an inductive coupling between the transmitter 1000 and the receiver 2000 is performed. Increasing the coefficient can minimize energy loss. In addition, when the wireless power transmission system transmits power in a self-resonant manner, the transmission impedance matching unit 1300 may change a separation distance between the transmitter 1000 and the receiver 2000, or may have a plurality of foreign objects (FOs). It is possible to make real-time correction of impedance matching according to the change of matching impedance on the energy transmission line due to the change of the characteristics of the coil according to mutual influences by devices, etc., and the correction method is a multi-matching method using a capacitor and a multi-antenna. It may be a matching method or a method using a multi-loop.

The transmitting coil 1400 may be implemented by a plurality of coils or a singular coil, and when the transmitting coil 1400 is provided in plural, they may be spaced apart from each other or overlapping with each other, and they may be overlapped with each other. In this case, the overlapping area may be determined in consideration of the variation in magnetic flux density. In addition, when manufacturing the transmitting side coil 1400 may be manufactured in consideration of the internal resistance and radiation resistance, in this case, if the resistance component is small, the quality factor (Quality factor) can be increased and the transmission efficiency can be increased.

The communication and control unit 1500 may include a transmitting side control unit 1510 and a transmitting side communication unit 1520. The transmitter side control unit 1510 takes into account at least one of a power requirement of the receiver 2000, a current charge amount, a voltage Vrect of the rectifier output terminal of the receiver unit, each charging efficiency of a plurality of receivers, and a wireless power scheme. It may serve to adjust the output voltage (or the current Itx_coil flowing in the transmission coil) of the DC converter 1100. The DC / AC converter 1200 is driven in consideration of the maximum power transmission efficiency. Frequency and switching waveforms for controlling power to be transmitted, and an operation of the receiver 2000 using an algorithm, a program, or an application required for control read from a storage unit (not shown) of the receiver 2000. The transmitting side control unit 1510 may be referred to as a microprocessor, a micro controller unit, or a micom. The transmitting side communication unit 1520 may communicate with the receiving side communication unit 2620, and may use a short range communication method such as Bluetooth, NFC, or Zigbee as an example of a communication method. The 1520 and the receiving-side communication unit 2620 may transmit and receive the charging state information and the charge control command, etc. The charging state information may include the number of the receiving unit 2000, the battery remaining amount, the number of charges, the amount of usage, Battery capacity, a battery ratio, and a transmission power amount of the transmitter 1000. The transmitter-side communication unit 1520 may transmit a charging function control signal for controlling a charging function of the receiver 2000, and may be charged. The function control signal may be a control signal that controls the receiver 2000 to enable or disable the charging function.

As such, the transmitting-side communication unit 1520 may be communicated in an out-of-band format configured as a separate module, but is not limited thereto. The receiving unit may use a power signal transmitted by the transmitting unit. By using the feedback signal transmitted to the transmitter and the frequency of the power signal transmitted by the transmitter by using a frequency shift (Frequency shift), the transmitter may communicate in an in-band format in which the transmitter transmits the signal to the receiver. have. For example, the receiver may modulate the feedback signal and transmit information such as charge start, charge end, battery state, etc. to the transmitter through the feedback signal. In addition, the transmitting side communication unit 1520 may be configured separately from the transmitting side control unit 1510, and the receiving unit 2000 may also include the receiving side communication unit 2620 in the control unit 2610 of the receiving apparatus or may be configured separately. have.

In addition, the transmitter 1000 of the wireless power transmission system according to the embodiment may further include a detector 1600.

The detector 1600 may include an input signal of the transmitting side AC / DC converter 1100, an output signal of the transmitting side AC / DC converter 1100, an input signal of the transmitting side DC / AC converter 1200, and a transmitting side. The output signal of the DC / AC converter 1200, the input signal of the transmitting impedance matching unit 1300, the output signal of the transmitting impedance matching unit 1300, the input signal of the transmitting coil 1400, or the transmitting coil ( At least one of the signals on the 1400 may be detected. For example, the signal may include at least one of information on current, information on voltage, or information on impedance. The detected signal is fed back to the communication and control unit 1500, and based on this, the communication and control unit 1500 transmits an AC / DC converter 1100, a DC / AC converter 1200, and an impedance matching transmitter. The unit 1300 may be controlled. In addition, based on the detection result of the detector 1600, the communication and controller 1500 may perform Foreign Object Detection (FOD). The detected signal may be at least one of a voltage and a current. The detector 1600 may be configured with different hardware from the communication and control unit 1500, or may be implemented with one piece of hardware.

<Receiver>

4A and 4B are block diagrams illustrating a receiver (or a receiver) as one of subsystems configuring a wireless power transmission system. Referring to FIG. 4A, the wireless power transmission system according to the embodiment may include a transmitter 1000 and a receiver 2000 that receives power wirelessly from the transmitter 1000. The receiving device 2000 converts the AC power from the receiving side resonant circuit unit 201 and the receiving side resonant circuit unit 201 to receive an AC signal transmitted from the transmitting apparatus 1000 and outputs the DC signal as a DC signal. The current voltage of the load 2500 and the receiving side resonant circuit unit 201 that are charged by receiving the DC signal output from the receiving power converter 202 and the receiving power converter 202 are sensed or received. Perform impedance matching of the side resonant circuit unit 201, control the power conversion of the receiving side power conversion unit 202, adjust the level of the output signal of the receiving side power conversion unit 202, or the receiving side. The input or output voltage or current of the power converter 202 is sensed, the output signal of the power converter 202 of the receiving side is controlled or not supplied to the load 2500, or communicates with the transmitter 1000 That can be It may include sincheuk control section 203. The receiving side power converter 202 may include a power converter that converts an AC signal into a direct current, a power converter that outputs a direct current by varying the level of the direct current, and a power converter that converts a direct current into an alternating current. In addition, referring to FIG. 4B, the wireless power transmission system according to the embodiment includes a transmitter (or a transmitter) 1000 and a receiver (or receiver) 2000 that receives power from the transmitter 1000 wirelessly. The receiver 2000 may include a receiver side resonant circuit unit 2120, a receiver side AC / DC converter 2300, and a DC / DC receiver configured as a receiver side coil unit 2100 and a receiver side impedance matching unit 2200. The DC converter 2400, the load 2500, and the receiver side communication and control unit 2600 may be included. The receiving side AC / DC converter 2300 may be referred to as a rectifying unit rectifying the AC signal into a DC signal.

The receiving coil unit 2100 may receive power through a magnetic induction method or a magnetic resonance method. As such, it may include at least one of an induction coil and a resonant coil according to a power reception method.

In one embodiment, the receiving side coil unit 2100 may be disposed in a portable terminal together with a near field communication (NFC). The receiving side coil unit 2100 may be the same as the transmitting side coil unit 1400, and the dimensions of the receiving antenna may vary according to electrical characteristics of the receiving unit 200.

The receiving impedance matching unit 2200 performs impedance matching between the transmitter 1000 and the receiver 2000.

The receiving AC / DC converter 2300 rectifies the AC signal output from the receiving coil unit 2100 to generate a DC signal. The output voltage of the receiving side AC / DC converter 2300 may be referred to as a rectified voltage Vrect, and the receiving side communication and control unit 2600 may output the output voltage of the receiving side AC / DC converter 2300. The minimum rectified voltage Vrect_min (or the minimum output voltage Vrect_min), which is the minimum value of the output voltage of the receiving side AC / DC converter 2300, and the maximum rectified voltage Vrect_max, which is the maximum value, may be detected or changed. Information about an optimum rectified voltage Vrect_set (or an optimum output voltage Vrect_set) having a voltage value of any one of the maximum output voltage Vrect_max, and a value between the minimum value and the maximum value. The same state parameter information may be transmitted to the transmitter 1000.

The receiving DC / DC converter 2400 may adjust the level of the DC signal output from the receiving AC / DC converter 2300 according to the capacity of the load 2500.

The load 2500 may include a battery, a display, a voice output circuit, a main processor, a battery manager, and various sensors. The load 2500 may include at least a battery 2510 and a battery manager 2520 as shown in FIG. 4A. The battery manager 2520 may adjust the voltage and current applied to the battery 2510 by detecting a charging state of the battery 2510.

The receiving side communication and control unit 2600 may be activated by the wake-up power from the transmitting side communication and the control unit 1500, perform communication with the transmitting side communication and the control unit 1500, and serve as a sub-unit of the receiving unit 2000. You can control the operation of the system.

The receiver 2000 may be configured in singular or plural to receive energy from the transmitter 1000 at the same time wirelessly. That is, in the wireless resonant wireless power transmission system, the plurality of target receivers 2000 may receive power from one transmitter 1000. In this case, the transmitter matching unit 1300 of the transmitter 1000 may adaptively perform impedance matching between the plurality of receivers 2000. The same may be applied to the case where a plurality of receiving side coil parts are independent of each other in a magnetic induction method.

In addition, when the receiver 2000 is configured in plural, the power reception method may be the same system or may be a different type of system. In this case, the transmitter 1000 may be a system for transmitting power in a magnetic induction method or a magnetic resonance method or a system using both methods.

On the other hand, when looking at the signal size and frequency relationship of the wireless power transmission system, in the case of the wireless power transmission of the magnetic induction method, the transmitting side AC / DC converter 1100 in the transmitter 1000 is tens or hundreds of V (for example It can receive and transmit AC signal of tens or hundreds of Hz (for example, 60Hz) of 110V ~ 220V) and convert it into DC signal of several to tens of V and hundreds of V (for example, 10V ~ 20V). The side DC / AC converter 1200 may receive a DC signal and output an AC signal having a KHz band (for example, 125 KHz). The receiving side AC / DC converter 2300 of the receiving unit 2000 receives an AC signal having a KHz band (for example, 125 KHz) and receives a direct current of several V to several tens of V and hundreds of V (for example, 10 V to 20 V). The signal may be converted into a signal and output, and the receiving side DC / DC converter 2400 may output a DC signal suitable for the load 2500, for example, a 5V DC signal, and transmit the DC signal to the load 2500. In the case of the wireless power transmission of the self-resonant method, the transmitting side AC / DC converter 1100 in the transmitting unit 1000 has tens or hundreds of V bands (for example, 110V to 220V) of several tens or hundreds of Hz bands (for example, It receives the AC signal of 60Hz) and converts it into a DC signal of several V to several tens of V and several hundred V (for example, 10V to 20V), and outputs the DC signal. The transmitter DC / AC converter 1200 applies a DC signal. AC signal in the MHz band (for example, 6.78 MHz) can be output. The receiver AC / DC converter 2300 of the receiver 2000 receives an AC signal of MHz (for example, 6.78 MHz) and receives a receiver of several V to several tens of V and several hundred V (for example, 10 V to 20 V). The DC signal may be converted into a DC signal and output, and the DC / DC converter 2400 may output a DC signal of, for example, 5V suitable for the load 2500 and transmit the DC signal to the load 2500.

<Operation Status of Transmitter>

5 is a flowchart illustrating an operation of a wireless power transmission system, focusing on an operation state of a transmitter according to an embodiment. 6 is a graph showing a driving state of the power converter according to the load of the receiver.

Referring to FIG. 5, the transmitting apparatus according to the embodiment may have at least 1) a selection state, 2) a detection state, 3) an identification and setting state, 4) a power transmission state, and 5) a charging termination state.

[Selection Phase]

(1) In the selected state, the transmitter 1000 may perform a detection process to select the receiver 200 existing in the sensing area or the charging area.

(2) As described above, the sensing area or the charging area may refer to an area in which an object in the corresponding area may affect the characteristics of the power of the transmitting power converter 101. Compared with the detection state, the detection process for selecting the reception apparatus 2000 in the selection state is based on the transmission apparatus 1000 instead of receiving a response from the reception apparatus 2000 using a power control message. The power conversion unit detects a change in the amount of power for forming the wireless power signal and checks whether an object exists within a predetermined range. The detection process in the selection state may be referred to as an analog detection process (analog ping) in that an object is detected using a wireless power signal instead of a packet in a digital format in a detection state to be described later.

(3) In the selected state, the transmitter 1000 may detect that an object enters or exits the sensing area or the charging area. In addition, the transmitter 1000 may distinguish between the receiver 2000 capable of wirelessly transmitting power from other objects in the sensing area or the charging area and other objects (eg, a key, a coin, etc.). .

As described above, since the distance at which power can be wirelessly transmitted is different according to the inductive coupling method and the resonance coupling method, the sensing areas in which the object is detected in the selected state may be different from each other.

(4) First, when power is transmitted according to an inductive coupling method, the transmission apparatus 1000 in the selected state may monitor an interface surface (not shown) to detect the placement and removal of objects.

In addition, the transmitter 1000 may detect the position of the wireless power receiver 2000 placed on the interface surface.

(5) When the transmitting apparatus 1000 includes one or more transmitting coils, the selection state enters the detection state, and in response to the detection signal from the object is transmitted using the respective coils in the detection state. Or whether the identification information is transmitted from the object after entering the identification state.

The transmitter 1000 may determine a coil to be used for wireless power transmission based on the detected position of the receiver 2000 obtained through the above process.

(6) In addition, when power is transmitted according to the resonance coupling method, at least one of the frequency, current, and voltage of the power converter due to an object in the sensing area or the charging area is changed in the transmission apparatus 1000 in the selected state. The object can be detected by detecting the fact.

(7) Meanwhile, the transmission apparatus 1000 in the selected state may detect an object by at least one of the detection methods according to the inductive coupling method and the resonance coupling method.

(8) The transmitter 1000 may perform an object detection process according to each power transmission method, and then select a method of detecting the object from a combination method for wireless power transfer in order to proceed to other states. .

(9) Meanwhile, the wireless power signal formed by the transmitting apparatus 1000 in the selected state to detect an object and the wireless power signal formed for digital detection, identification, setting, and power transmission in subsequent states have their frequency. , Strength, etc. may vary. This means that the selected state of the transmitter 1000 corresponds to an idle phase for detecting an object, so that the transmitter 1000 reduces power consumption in the air or generates a specialized signal for efficient object detection. To make it possible.

[Ping Phase]

(1) In the detection state, the transmitter 1000 may perform a process of detecting the receiver 2000 existing in the sensing area or the charging area through a power control message. Compared with the detection process of the receiving apparatus 2000 using the characteristics of the wireless power signal in the selected state, the detection process in the detection state may be referred to as digital ping.

(2) The transmitter 1000 forms a wireless power signal for detecting the receiver 2000, demodulates a wireless power signal modulated by the receiver 2000, and from the demodulated wireless power signal, A power control message in the form of digital data corresponding to the response to the detection signal may be obtained.

(3) The transmitter 1000 may recognize the receiver 2000 that is the target of power transmission by receiving a power control message corresponding to the response to the detection signal.

(4) The detection signal formed by the transmitter 1000 in the detection state to perform a digital detection process may be a wireless power signal formed by applying a power signal of a specific operating point for a predetermined time.

The operation point herein may mean a frequency, a duty cycle, and an amplitude of a voltage applied to the transmitting coil unit 1400.

The transmitter 1000 may generate the detection signal generated by applying the power signal of the specific operation point for a predetermined time, and attempt to receive a power control message from the receiver 2000.

Meanwhile, the power control message corresponding to the response to the detection signal may be a message indicating the strength of the wireless power signal received by the receiver 2000. For example, the receiver 2000 may transmit a signal strength packet including a message indicating the strength of the received wireless power signal as a response to the detection signal. The packet may be configured to include a header indicating that the packet indicates a signal strength and a message indicating the strength of the power signal received by the receiving apparatus 2000. The strength of the power signal in the message may be a value representing a degree of coupling of inductive coupling or resonance coupling for power transmission between the transmitter 1000 and the receiver 2000.

(6) After the transmitter 1000 receives the response message for the detection signal and discovers the receiver 2000, the transmitter 1000 may extend the digital detection process to enter the identification and detection state. That is, the transmitter 1000 may receive the power control message required in the identification and detection state by maintaining the power signal of the specific operation point after discovering the receiver 2000.

However, when the transmitter 1000 does not find the receiver 2000 capable of delivering power, the operating state of the transmitter 1000 may return to the selected state.

[Identification and Configuration Phase]

(1) In the identification and setting state, the transmitting apparatus 1000 may receive the identification information and / or setting information transmitted by the receiving apparatus 2000 so as to efficiently transmit power.

(2) In the identification and setting state, the receiving device 2000 may transmit a power control message including its own identification information. To this end, the receiving device 2000 may transmit, for example, an identification packet including a message indicating the identification information of the receiving device 2000. The packet may be configured to include a header indicating that the packet indicates identification information and a message including identification information of the receiving apparatus 2000. The message may be configured to include information indicating a version of a protocol for wireless power transmission, information identifying a manufacturer of the receiver 2000, information indicating whether an extended device identifier exists, and a basic device identifier. In addition, when it is indicated that the extended device identifier exists in the information indicating whether the extended device identifier exists, an extended identification packet including the extended device identifier may be separately transmitted. The packet may be configured to include a message indicating that the packet indicates an extension device identifier and an extension device identifier. When the extended device identifier is used as such, information based on the manufacturer's identification information, the basic device identifier, and the extended device identifier may be used to identify the receiver 2000.

(3) In the identification and setting state, the receiving device 2000 may transmit a power control message including information on the expected maximum power. To this end, the receiving device 2000 may transmit, for example, a configuration packet. The packet may be configured to include a header indicating that the packet is a setup packet and a message including information on the expected maximum power.

The message may be configured to include a power class, information on an expected maximum power, an indicator indicating a method of determining a current of a main cell on the side of the wireless power transmitter 1000, and an optional number of configuration packets. The indicator may indicate whether or not the current of the main cell of the transmitter 1000 side is to be determined as specified in the protocol for wireless power transmission.

Meanwhile, the transmitter 1000 may generate a power transfer contract used for power charging with the receiver 2000 based on the identification information and / or configuration information. The power transfer protocol may include limits of parameters that determine power transfer characteristics in the power transfer state.

(5) The transmitter 1000 may end the identification and setting state before returning to the power transmission state and return to the selection state. For example, the transmitter 1000 may terminate the identification and setup state in order to find another receiver 2000 that can receive power wirelessly.

[Power Transfer Phase]

(1) The transmitter 1000 in the power transmission state transmits power to the receiver 2000.

In this case, the transmitter 1000 may transmit the wireless power by controlling the power converter 101 according to the version of the receiver 2000 based on the received identification packet. In detail, when the receiver 2000 corresponds to a low power level by checking the version of the receiver 2000, the power converter 101 may be driven by a half bridge inverter to transmit wireless power. When the reception device 2000 corresponds to a middle power level, the power conversion unit 101 may be driven by a full bridge inverter to transmit wireless power.

More specifically, referring to FIG. 6, the load of the receiver 2000 increases as the version of the receiver 2000 moves from the low power class to the middle power class. In this case, the power converter 101 of the transmitter 1000 may transmit the wireless power to the receiver 2000 corresponding to a small load, that is, a low power class, as the half converter is driven by the half bridge inverter.

Also, for the low power receiver 2000 having a load smaller than the second load Load2, the wireless power may be changed through at least one of a duty ratio and a switching frequency of the switching elements Q2 and Q3. The amount can be adjusted. Specifically, the switching frequency of the switching elements Q2 and Q3 of the power converter 101 with respect to the receiver 2000 having a load smaller than that of the first load Load1 is a duty in a state where the third driving frequency f3 is fixed. The amount of wireless power can be adjusted by adjusting the duty ratio, and under a fixed duty ratio for the receiver 2000 having a load greater than 1 load, the switching frequency is adjusted, that is, the third driving. The amount of wireless power may be adjusted according to the frequency change between the frequency f3 and the second driving frequency f2. However, the present invention is not limited to the drawings, and the amount of wireless power may be adjusted according to the switching frequency change with respect to the receiver 2000 having a load smaller than the first load Load1, and the first load Load1. For a receiver 2000 having a larger load, the amount of wireless power may be adjusted according to the duty ratio change, and the switching frequency and duty ratio may be simultaneously changed and the amount of wireless power may be adjusted.

In addition, the power converter 101 drives the full bridge inverter with respect to the middle power receiver 2000 having a load larger than that of the second load Load2, and the switching frequency of the switching elements Q1 to Q4 is set to the second. In the state fixed at the driving frequency f2, the amount of wireless power can be adjusted through phase shift or switching frequency change. In detail, the driving frequency of the switching elements Q1 to Q4 of the power converter 101 with respect to the receiving device 2000 having a load smaller than that of the third load Load3 is in phase while being fixed at the second driving frequency f2. A change in the switching frequency of the switching elements Q1 to Q4 of the power converter 101 can be adjusted for the receiver 2000 having a load larger than the third load Load3 through the transition, That is, the amount of wireless power may be adjusted according to the change of the driving frequency between the second driving frequency f2 and the first driving frequency f1. However, the present invention is not limited to the drawings, and the amount of wireless power can be adjusted according to the switching frequency change with respect to the receiving apparatus 2000 having a load smaller than the third load (Load3), and the third load (Load3). For a receiver 2000 having a larger load, the amount of wireless power may be adjusted according to the phase shift, and the amount of wireless power may be adjusted by simultaneously changing the switching frequency and shifting the phase.

(3) The transmitting apparatus 1000 receives a power control message from the receiving apparatus 2000 while transmitting power, and the characteristic of the power applied to the transmitting coil unit 1400 in response to the received power control message. Can be adjusted. For example, the power control message used to adjust the power characteristic of the transmitting coil may be included in a control error packet. The packet may be configured to include a message indicating a control error packet and a message including a control error value. The transmitter 1000 may adjust power applied to the transmitter coil according to the control error value. That is, when the control error value is 0, since the control point required by the receiver 2000 and the actual control point of the receiver 2000 are substantially the same, The applied current can be maintained, reduced for negative values, and adjusted to increase for positive values.

(4) In addition, in the transmitting apparatus 1000, the power converter 101 drives the half bridge inverter at the initial driving time of the power transmission state, and the first control error packet (1 ^st Control Error Packet), which is the first control error packet. After receiving the signal, the version of the receiver 2000 is determined based on the received identification packet, and when the receiver 2000 corresponds to a low power level, the half-bridge inverter of the power converter 101 is driven. In the case of the middle power class, it can be changed to drive the full bridge inverter.

(5) In the power transfer state, the transmitter 1000 may monitor parameters in a power transfer contract generated based on the identification information and / or configuration information. As a result of monitoring the parameters, if the power transmission with the receiving apparatus 2000 violates the limitations included in the power transmission protocol, the transmitting apparatus 1000 cancels the power transmission and returns to the selection state. I can go.

(6) The power transfer protocol also relates to the threshold current value of the current induced on the receiving coil unit 2100 of the receiving apparatus 2000 and the characteristics of the power transmitted from the transmitting apparatus 1000 to the receiving apparatus 2000. It may include boundary conditions. (5) The transmitting apparatus 1000 may terminate the power transmission state based on the power control message transmitted from the receiving apparatus 2000.

For example, when the charging of the battery is completed while the receiving device 2000 is charging the battery by using the transmitted power, a power control message requesting the transmission device 1000 to stop the wireless power transmission is sent. I can deliver it. In this case, after receiving the message requesting that the power transmission be stopped, the transmitter 1000 may end the wireless power transmission and return to the selection state.

For another example, the receiver 2000 may transmit a power control message requesting renegotiation or reconfigure to update an already generated power transfer protocol. The receiver 2000 may transmit a message for requesting renegotiation of the power transfer protocol when a greater or less amount of power is required than the amount of currently transmitted power. In this case, after receiving the message requesting the renegotiation of the power transfer protocol, the transmitter 1000 may end the wireless power transmission and return to the identification and setting state.

To this end, the message transmitted by the receiving device 2000 may be, for example, an end power transfer packet as shown in FIG. 18. The packet may be configured to include a message indicating a power transmission interruption packet and a message including a power transmission interruption code indicating a reason for the interruption. The power transmission stop code includes charge complete, internal fault, over temperature, over voltage, over current, battery failure, reconfigure, It may indicate one of a no response and an unknown error.

<Power transfer control>

-Method of determining the required power of the receiving device.

7 is a flowchart illustrating a method for determining a required power of a receiver.

Referring to FIG. 7, the reception apparatus 2000 1) determines a desired control point (S210), 2) detects an actual control point (S230), and 3 ) The control error value generation step S250 may be performed to determine the power to be received, that is, the required power.

In detail, in operation S210 of determining a desired control point, the receiving device 2000 may determine a required control point regarding voltage, current, temperature, and the like. In operation S230, the receiver 2000 may determine an actual control point regarding an actual voltage, a current, a temperature, and the like. When the receiver 2000 determines the actual control point, various methods such as voltage, current detection, and temperature sensing may be applied, and the process may be performed at any time during the power transmission state. In operation S250, the receiving device 2000 may generate a control error value based on a difference between a required control voltage value and an actual control voltage value. The control error value may be a parameter indicating a positive value and a negative value. When the actual power amount is smaller than the required power amount, the control error value may refer to a positive value, and the actual power amount is greater than the required power amount. In many cases, the control error value may refer to a negative value and may have a zero value when the required amount of power and the actual amount of power are the same. As described above, the coupling coefficient may be drastically lowered according to the alignment between the transmitter 1000 and the receiver 2000 in the power control process, and thus the required amount of power of the receiver 2000 may be instantaneously increased. In addition, the receiver 2000 may request the transmitter 1000 the amount of power required so that the current induced in the receiver coil unit 2100 exceeds a threshold value, but the transmitter 1000 receives the receiver side nose. Since the wireless power generated within the range of the reset driving frequency is transmitted based on the threshold value of the current induced in the portion 2100, the problem that the receiver 2000 is damaged is prevented.

The control error value may be transmitted to the transmitter 1000 in the form of a control error packet.

When the new transmission power is received from the transmitting device that has received the control error value, it may be determined whether the new transmission power satisfies the requested power through the above-described steps.

<Power control method>

8 is a graph showing the magnitude of the coil current on the transmitting-side coil unit according to the driving frequency. 9 and 10 are flowcharts illustrating operations of a transmitter including a driving frequency threshold value setting step.

Referring to FIG. 8, the power conversion unit 101 may determine whether a version of the reception device 2000 included in the identification packet received in the identification and setting state, that is, whether the reception device 2000 is low power or middle power. One of the half-bridge inverters and the full-bridge inverters may operate, and the switching frequency of the power converter 101 may be any one of the driving frequency values in the range of the first driving frequency f1 to the third driving frequency f3. Can be.

In addition, the frequency values of the first driving frequency f1, which is the minimum frequency, and the third driving frequency f3, which is the maximum frequency, may be preset according to the capacity or type of the transmitter 1000.

In general, when the coupling factor between the transmitter 1000 and the receiver 2000 is greater than 0.5, the switching frequency may be formed at the second driving frequency f2. In this case, the transmitting coil current on the transmitting side coil unit 1400 may be the first current A1. At this time, in order to increase the amount of wireless power, the driving frequency may be changed. That is, in the half bridge inverter driving state, the amount of wireless power can be increased by increasing the driving frequency, and in the full bridge inverter driving state, the amount of wireless power can be increased by decreasing the driving frequency. In response to the misalignment of the receiving device 2000, the coupling coefficient becomes smaller than 0.5, and the half-bridge inverter driving state is maintained in order to keep the amount of power to be received by the receiving device 2000 constant. In FIG. 3, the wireless power amount may be increased by increasing the driving frequency, and in the full bridge inverter driving state, the wireless power amount may be increased by lowering the driving frequency.

However, if the coupling coefficient is abruptly changed or the coupling coefficient is significantly lowered, there may be a change to the first drive frequency f1 having the lowest driving frequency or to a third drive frequency f3 having the maximum driving frequency. have. In this case, the current applied on the transmitting side coil unit 1400 may be equal to or greater than the second current A2 and the third current A3. In this case, as shown in FIG. 9, the amount of current induced in the receiving coil unit 2100 of the receiving apparatus 2000 may also increase rapidly, which may damage the receiving apparatus 2000, thus resetting the threshold value of the driving frequency. This can be prevented. The threshold value of the driving frequency is reset before entering the power transfer state based on the information on the current threshold value of the receiver 2000 included in the identification packet, or the first control in the state of entering the power transfer state as shown in FIG. 10. After receiving the error packet, the error packet may be reset based on the information about the current threshold value of the receiver 2000 included in the identification packet. For example, when the current applied to the transmitting coil unit 1400 corresponds to the fourth current A4 and the amount of current induced in the receiving coil unit 2100 corresponds to a threshold value, the transmitter 1000 The threshold of the driving frequency may be determined as a frequency within a range of the fourth to fifth driving frequencies f4 and f5 that match the fourth current A4.

In addition, when the driving frequency is fixed, the magnitude of the transmitting coil current on the transmitting coil unit 1400 may be changed through the duty ratio or the phase shift of the switching element, and accordingly, the amount of current induced in the receiving coil unit 2100 may be adjusted. have. Even in this case, the size of the transmitting coil current on the transmitting coil unit 1400 is limited in consideration of the threshold value of the amount of current induced in the receiving coil unit 2100, thereby preventing the receiving apparatus 2000 from being damaged. Can be.

<Power transmission control method>

11 is a diagram illustrating in detail a control unit of a transmitter for a power transmission control method. 12 is a timing diagram of a transmitter in a power transmission state.

Referring to FIG. 11, in the power transmission control method, the control unit 103 of the transmission apparatus 1000 may control the current of the transmission coil unit 1400 to become a new transmission coil current. This power transfer control can be implemented based on a proportional integral differential (PID) algorithm.

In order to execute the PDI algorithm, the transmitter 1000 may include a first operator 11 and a second operator 15 and a proportional controller 12a, an integration controller 12b, and a derivative controller 12c. The first to fifth amplifiers 13a, 13b, 13c, 13d, and 13e and the first and second summers 14a and 14b may be included. The power conversion unit 101 may be performed by performing the following process. Can be controlled.

The following j = 1, 2, 3, .... may refer to the order of the control error packet received by the transmitter 1000. Each of the first to fifth amplifiers 13a, 13b, 13c, 13d, and 13e may have at least one function of an amplifier, a buffer, and a delay.

(1) New transmit coil current calculation step.

1) When the first operator 11 of the transmitter 1000 receives j (th) Control Error Packet, the new transmitter coil current td (j) may be calculated according to Equation (3).

Equation 3

2) where ta (j-1) refers to the actual (current) actual primary cell current, determined according to the previous control error packet c (j-1), and c (j) is j (th) It may refer to a control error value included in a control error packet. In addition, ta (0) may refer to a current of the transmitting coil unit 1400 at the start of the power transmission state.

A magnetic field may be generated in the transmission coil unit 1400 based on the transmission coil current to generate output power.

3) The first operator 11 receives an actual transmission coil current ta (j-1) through a j-th control error packet and a first amplifier 13a, and performs a calculation process according to Equation 3 above. After passing through the new transmission coil current td (j) can be calculated and output.

4) If c (j), which is a control error value, is non-zero (non-zero), the transmitter 1000 may adjust the transmit coil current for a preset time (t_active in FIG. 13). . To this end, the transmitter 1000 may execute a loop including a step to be described later.

Here i = 1, 2, 3, .. max may refer to the number of iterations of the loop.

 (2) Error calculation step.

1) The transmitter 1000 according to equation (4) i according to the difference between the new transmission coil current (td (j)) and the actual transmission coil current (ta (j, i-1)) according to the i-1 th loop The error in the first loop can be calculated.

Equation 4

Here, ta (j, i-1) may refer to the transmission coil current determined by the i-1 th loop. Here, ta (j, 0) may refer to the actual transmission coil current at the start of the loop.

2) The first adder 14a sums the new transmit coil current td (j) and the actual transmit coil current ta (j, i-1) determined by the i-1 th loop from the second amplifier 13a. By calculating the error (error) and output the calculated error to the PID controller 12.

(3) Control amount calculation step.

1) The PID controller 12 of the transmitter 1000 determines a control amount through a proportional control (P) for changing the control amount in proportion to an error, an integral control (I) for integrating and controlling the error, and an amount of change in the error. Differential control D can be executed.

The PID controller 12 may calculate a proportional term, an integral term, and a derivative term, as represented by equation (5). Specifically, proportional controller 12a calculates proportional element P (j, i) based on the error, integral controller 12b calculates integral element I (j, i) based on the cumulative value of the error, and derivative The controller 12c may calculate the derivative element D (j, i) based on the amount of change in the error.

Equation 5

2) where Kp is proportional gain, Ki is integral gain, and Kd is differential gain. And t_inner is the time required for one loop to repeat. And integral term I (j, 0) = 0 and error e (j, 0) = 0. In addition, the transmitter 1000 may limit the integral term I (j, i) within the range of -M_I .. + M_I, and may change the calculated integral element I (j, i) to an appropriate boundary value as necessary. . Here, M_I is an integral term limit parameter.

3) The output signal of the integrating controller 12b can be fed back to its input via the fourth amplifier 13d, where the fed back output signal is the integral term I of the previous (i-1 &lt; th &gt;) loop. (j, i-1)). In addition, the input signal of the derivative controller 12c can be input to the differential controller 12c via the third amplifier 13c, where the input signal is the error (e (j) of the previous (i-1 &lt; th &gt;) loop. , i-1)).

4) The second summer 14b of the transmitter 1000 is the proportional element P (j, i) output from the proportional controller 12a and the integral element I output from the integration controller 12b, as shown in equation (6). The sum (i) and the control amount PID (j, i) can be calculated by summating (j, i) and the derivative element D (j, i) output from the derivative controller 12c.

Equation 6

5) According to this calculation, the transmitter 1000 may output the current control amount PID (j, i), and the current control amount PID (j, i) is within the range of -M_PID .. + M_PID. You can limit it. M_PID is a PID output limit parameter.

(4) New control variable value calculation step.

1) The transmitter 1000 may calculate a new controlled variable value based on Equation (7).

Equation 7

2) Here, Sv may refer to a scaling factor based on a control variable.

Also, control variable v (i, 0) = v (j-1, i_max), and v (0,0) refers to the actual value of the controlled variable at the start of the power transfer state. can do. The control variable may be any one of an operating frequency, a duty cycle of the DC / AC converter 1200, or an amount of change in an input voltage or a phase shift of the DC / AC converter 1200. Can be one.

If the calculated v (j, i) exceeds the preset range, the transmitter 1000 may change the calculated v (j, i) to an appropriate limit value.

3) The second operator 15 controls the current (i) control amount PID (j, i) and its output via the fifth amplifier 13e to feed back the control variable of the previous (i-1st) loop. Based on the value, a new control variable value v (j, i) may be calculated according to Equation 7.

4) At least one of the scaling factor Sv or the new control variable value v (j, i) may be adjusted to appropriately limit the current induced in the receiving coil unit 2100 within the current threshold value range.

In more detail, the scaling factor Sv may vary according to a driving frequency range as shown in Table 1 as an example.

TABLE 1

In addition, even if the driving frequency of the transmitter 1000 is in the range of 110 kHz to 205 kHz as shown in Table 1, the current threshold value induced on the receiver side coil part 2100 of the receiver 2000 received in the identification state. If it is necessary to limit the driving frequency to a value larger than 110 kHz and smaller than 205 kHz, the lowest scaling factor Sv of the scaling factors Sv may be changed to a value larger than 1.5, and the maximum scaling factor Sz. ) Can be changed to a value less than 5. Thus, the frequency range of the driving frequency can be reset by making the minimum and maximum values of the driving frequency different. The scaling factor Sv may be reset before entering the power transfer state as described with reference to FIG. 9 or after receiving the first control error packet as described with reference to FIG. 10.

As another example, when the control variable becomes an operating frequency, the power conversion unit 101 operates at a frequency higher than 160 kHz in the driving state of the half bridge inverter of the power conversion unit 101 at the boundary of 160 kHz in Table 1. The new control variable value v (j, i) may be changed so that the driving frequency does not exceed the limit maximum value (for example, the fourth driving frequency f4 of FIG. 7). In the full bridge inverter driving state of the unit 101, the power conversion unit 101 may drive at a driving frequency lower than 160 kHz, and the driving frequency is the minimum limit value (for example, the fifth driving frequency f5 of FIG. 7). The new control variable value v (j, i) can be changed so as not to exceed.

(5) controlling the power converter based on the new control variable.

1) The transmitter 1000 may apply a control value v (j, i) of a new value to the DC / AC converter 1200, and the new control variable v (j, i) may be a receiving coil unit ( The current value induced at 2100 does not exceed the current threshold value and does not damage the receiving device 2000 even when the coupling coefficient is suddenly changed.

2) The transmitter 1000 may generate new power according to the transmission coil current ta (j, i) determined by the first calculator 11 based on the control value v (j, i) of the new value. have.

Meanwhile, referring to FIG. 12, the transmitter 1000 may determine the transmission coil current ta (j) for a time t_delay + t_active + t_settle after the reception end time of the j (th) control error packet.

In this case, t_delay may mean a time delay for performing power control according to the previous control error packet after receiving the previous control error packet, and t_active performs power control according to the previous control error packet (transmitted as an example according to the drawing). Power may be increased), and t_settle may mean settling time of a target power value.

On the other hand, when the gains Ki, Ki, Kd of the PID controller 12, the integral term limit parameter M_I, the PID output limit parameter M_PID, and v (j, i) exceed the preset ranges, The predetermined range and the scaling factor Sv at the time of determination are characterized by the transmission power characteristics of the power transfer contract, the specification of the transmitting apparatus 1000, the specification and capacity of the transmitting coil unit 1400, and the receiving apparatus. It may be determined in consideration of the current threshold of 2000 and the like.

As such, the transmitter 1000 receiving the control error packet may determine a new transmission coil current and determine a new transmission power based on the new transmission coil current. According to the new transmission power amount, the wireless power transmission may be stopped without generating the new transmission power, or the new transmission power may be generated to continue the wireless power transmission.

According to the embodiment, when the coupling coefficient is low due to the misalignment of the transmitter 1000 and the receiver 2000, the reception power of the receiver 2000 is lower than the power output from the transmitter 1000. The receiver 2000 may require more power, and thus the amount of transmit power of the transmitter 1000 may increase. At this time, since the wireless power is generated and transmitted within the reset driving frequency range in consideration of the current threshold value of the receiving device 2000, the receiving device 2000 is damaged due to excessive transmission power and heat generation due to excessive transmission power. You can solve the problem.

In particular, when the transmitter 1000 and the receiver 2000 are instantaneously and repeatedly caused by the shaking of the vehicle, such as a vehicle wireless charging system, the transmission power of the transmitter 1000 suddenly changes suddenly. Even in such a situation, since the induced current on the receiving side coil unit 2100 does not exceed a threshold value, damage to the receiving device 2000 can be prevented in advance.

In the detailed description of the present invention described above with reference to the preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge of the present invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the spirit and scope of the art. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

11 First Operator
12 PID Controller
12a proportional controller
12b integral controller
12c differential controller
13a first amplifier
13b second amplifier
13c third amplifier
13d fourth amplifier
13e fifth amplifier
14a first adding part
14b second adding part
15 Second Operator
101 power conversion unit
102 Resonant circuit part on the transmission side
103 control unit
1100 Sending side AC / DC converter (1600
1110 Rectifier
1120 Transmitter DC / DC converter
1200 DC / AC Converter
1300 Transmitter Impedance Matching Unit
1400 transmitting coil
1500 Sending side communication and control unit
1510 Sending side control unit
1520 Sending side communication unit
1600 detector
2000 receiver
2100 receiving side coil part
201, 2120 Receive Side Receive Circuit
2200 receiving side impedance matching unit
202 receiving power conversion unit
2300 receiving side AC / DC converter
2400 DC / DC Converter
2500 load
2510 batteries
2520 battery management unit
2600 Receive Side Communication and Control
203, 2610 receiving side control unit
2620 receiving side communication unit

Claims (27)

Receiving an identification packet from a wireless power receiver;
Receiving a control error packet from the wireless power receiver and determining a current of a transmission coil based on the control error packet; And
And adjusting a current of the transmission coil by changing a driving frequency within a first driving frequency range to generate the determined current.
The first driving frequency range is a frequency range preset in the wireless power transmitter,
The first driving frequency range is changed to the second driving frequency range according to the current threshold of the wireless power receiver,
And a current threshold value of the wireless power receiver is determined based on the identification packet. The method of claim 1,
And the changed driving frequency is a driving frequency of the inverter of the wireless power transmitter. The method of claim 1,
The maximum frequency of the modified second drive frequency range is a frequency corresponding to the current threshold of the wireless power receiver power transmission method of the wireless power transmitter. The method of claim 1,
The minimum frequency of the modified second driving frequency range is a frequency greater than the minimum frequency of the first driving frequency range power transmission method of the wireless power transmitter. The method of claim 1,
The maximum frequency of the modified second drive frequency range is a frequency smaller than the maximum frequency of the first drive frequency range power transmission method of the apparatus. The method of claim 1,
The current threshold of the wireless power receiver is a maximum current value that can damage the wireless power receiver power transmission method of the wireless power transmitter. inverter;
Transmission coil; And
Including a control unit,
The control unit,
Receive an identification packet from a wireless power receiver, Receives a control error packet (Control Error Packet) from the wireless power receiver,
Determine the current of the transmission coil based on the control error packet,
In order to generate the determined current to change the driving frequency within the first driving frequency range to adjust the current of the transmission coil,
The first driving frequency range is a frequency range preset in the wireless power transmitter,
The first driving frequency range is changed to the second driving frequency range according to the current threshold of the wireless power receiver,
And a threshold current value of the wireless power receiver is determined based on the identification packet. The method of claim 7, wherein
And the changed driving frequency is a driving frequency of an inverter of the wireless power transmitter. The method of claim 7, wherein
And a maximum frequency of the second driving frequency range corresponds to a current threshold of the wireless power receiver. The method of claim 7, wherein
And a minimum frequency of the second driving frequency range is a frequency greater than a minimum frequency of the first driving frequency range. The method of claim 7, wherein
And a maximum frequency of the second driving frequency range is a frequency smaller than a maximum frequency of the first driving frequency range. The method of claim 7, wherein
And a current threshold value of the wireless power receiver is a maximum current value that can damage the wireless power receiver. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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