KR102285416B1 - Apparatus and method for detecting foreign object in wireless power transmitting system - Google Patents

Abstract

The present invention relates to an apparatus and method for detecting foreign substances in a wireless power transmission system.
This specification generates power required information indicating the power required for the wireless power receiver, transmits the requested power information to the wireless power transmitter, and a power measurement unit for measuring power derived from the wireless power transmitter, and an auxiliary coil for receiving power derived from the wireless power transmitter.
According to the present invention, by recognizing foreign substances interposed between the wireless power transmitter and the wireless power receiver and allowing the user to remove the foreign substances, damage to the device by the foreign substances can be prevented.

Description

Apparatus and method for detecting foreign substances in a wireless power transmission system

The present invention relates to wireless power transmission, and more particularly, to an apparatus and method for detecting foreign substances in a wireless power transmission system.

In general, a battery pack is to supply power for the operation of a portable terminal (cell phone, PDA, etc.) in a charged state by receiving power (electrical energy) from an external charger. A cell and a circuit for charging and discharging (supplying electric energy to a portable terminal) of the battery cell are configured.

In an electrical connection method between a charger and a battery pack for charging electric energy to a battery pack used in such a portable terminal, commercial power is supplied and converted into voltage and current corresponding to the battery pack, and the battery pack is connected through the terminal of the battery pack. There is a terminal supply method that supplies electric energy to

However, this terminal supply method has problems such as an instantaneous discharge phenomenon due to a different potential difference between the terminals, burnout and fire caused by foreign substances, natural discharge, and deterioration of the life and performance of the battery pack.

Recently, in order to solve the above problems, a contactless charging system and control methods using a wireless power transmission method have been proposed.

The contactless charging system as described above includes a contactless power transmission device for supplying electric energy in a wireless power transmission method, and contactless power for charging a battery cell by receiving electrical energy supplied from the contactless power transmission device. It consists of a receiver, etc.

On the other hand, the contactless type charging system as described above is charged in a state in which the contactless power receiving device is placed on the contactless power transmitting device due to the contactless type characteristic.

At this time, when a foreign material such as metal is placed on the contactless power transmission device, power transmission is not performed smoothly due to the foreign material, and there are problems such as damage to the product due to overload.

An object of the present invention is to provide an apparatus and method for detecting foreign substances in a wireless power transmission system.

According to one aspect of the present invention, there is provided a wireless power receiver for detecting foreign substances. The device is coupled with a primary coil provided in the wireless power transmitter to generate a secondary coil for receiving wireless power, and required power information indicating the power required for wireless charging, and and a power measuring unit for transmitting the requested power information to the wireless power transmitter and measuring the received wireless power.

The power measuring unit may compose a received power measurement result obtained by performing a comparative analysis of the required power and the measured wireless power and transmit it to the wireless power transmitter.

According to another aspect of the present invention, there is provided a wireless power receiver for detecting foreign substances. The device is coupled to the main coil provided in the wireless power transmitter to generate a secondary coil for receiving wireless power, and power required information indicating the power required for wireless charging, and the wireless power transmitter generated by the wireless power transmitter Receives a generated power measurement report indicating power from the wireless power transmitter, composes a received power measurement result obtained by comparing and analyzing the required power and the generated wireless power, and receives the required power information and the received power measurement result and a power measurement unit for transmitting to the wireless power transmitter.

According to another aspect of the present invention, there is provided a wireless power receiving method by a wireless power receiving device for detecting foreign substances. The method includes generating required power information indicating the power required for wireless charging, transmitting the required power information to a wireless power transmitter, and an auxiliary coil coupled to the main coil provided in the wireless power transmitter Receiving wireless power using, measuring the received wireless power, composing a received power measurement result obtained by comparing and analyzing the required power and the measured wireless power, and comparing the received power measurement result to the wireless and transmitting to a power transmitter.

According to another aspect of the present invention, there is provided a wireless power transmitter for detecting foreign substances. The device includes a control unit for receiving power required information indicating power required for charging of the wireless power receiving device from the wireless power receiving device, and generating a control signal for providing the required power to the electric driving unit; The electric driving unit for applying an electric driving signal to the main coil based on a control signal, and the main coil connected to the electric driving unit and coupled with the auxiliary coil provided in the wireless power receiver to transmit wireless power includes

The control unit may receive a received power measurement result obtained by comparing and analyzing the wireless power measured by the wireless power receiver and the required power from the wireless power receiver.

According to another aspect of the present invention, there is provided a wireless power transmitter for detecting foreign substances. The device includes a control unit for receiving power required information indicating power required for charging of the wireless power receiving device from the wireless power receiving device, and generating a control signal for providing the required power to the electric driving unit; The electric driving unit for applying an electric driving signal to the main coil based on a control signal, the main coil connected to the electric driving unit and coupled with the auxiliary coil provided in the wireless power receiver to transmit wireless power; and a power measuring unit for measuring wireless power generated by the main coil.

The control unit configures a generated power measurement report indicative of the generated wireless power and transmits it to the wireless power receiver, and compares and analyzes the generated wireless power with the required power to obtain a received power measurement result of the wireless power It can be received from the receiving device.

According to another aspect of the present invention, there is provided a wireless power transmission method by a wireless power transmission device for detecting foreign substances. The method includes the steps of receiving, from the wireless power receiver, required power information indicating the power required for charging of the wireless power receiver, and generating a control signal for providing the requested power to the main device provided in the wireless power transmitter. applying an electric driving signal to the coil; transmitting wireless power generated in the main coil due to the application of the electric driving signal to the wireless power receiver having an auxiliary coil coupled to the main coil; and and receiving a received power measurement result obtained by comparing and analyzing the wireless power measured by the wireless power receiver and the required power from the wireless power receiver.

The present invention recognizes foreign substances interposed between the wireless power transmitter and the wireless power receiver and allows the user to remove the foreign substances, thereby preventing damage to the device by the foreign substances.

1 illustrates components of a wireless power transmission system according to an example of the present invention.
2 illustrates an example of a method for detecting foreign substances by a wireless power receiver using the present invention.
3 illustrates an example of a method for detecting foreign substances by a wireless power transmitter using the present invention.
4 illustrates another example of a method for detecting foreign substances by a wireless power transmitter using the present invention.
5 illustrates components of a wireless power transmission system according to another example of the present invention.
6 illustrates components of a wireless power transmission system according to another example of the present invention.
7 illustrates another example of a method for a wireless power receiver using the present invention to detect a foreign substance.
8 illustrates another example of a method for detecting foreign substances by a wireless power transmitter using the present invention.
9 is an operation flowchart between a wireless power transmitter and a wireless power receiver using the present invention.

As used hereinafter, the term "wireless power" is used to mean any form of energy associated with electric, magnetic, electromagnetic fields, etc. transmitted from a transmitter to a receiver without the use of physical electromagnetic conductors. Wireless power may also be called a power signal, and may refer to an oscillating magnetic flux enclosed by a main coil and a secondary coil. Power conversion in a system is described herein for wirelessly charging devices including, for example, mobile phones, cordless phones, iPods, MP3 players, headsets, and the like. In general, a basic principle of wireless energy transfer includes, for example, a magnetic induction coupling method or a magnetic resonance coupling (ie, resonance induction) method using frequencies less than 30 MHz. However, a variety of frequencies may be used, including frequencies that permit license-exempt operation at relatively high emission levels, for example below 135 kHz (LF) or at 13.56 MHz (HF).

1 illustrates components of a wireless power transmission system according to an example of the present invention.

Referring to FIG. 1 , a wireless power transmission system 1 includes a wireless power transmitter 10 and at least one wireless power receiver 30 . The wireless power transmitter 10 has a primary coil 12 and an electric driving unit 14 connected to the primary coil 12 for applying electric driving signals to the primary coil to generate an electromagnetic field. . A control unit 16 is connected to the electric drive unit 14 . This control unit 16 generates a control signal 106 that controls the AC signal required when the main coil 12 generates an induced magnetic field.

The wireless power transmitter 10 may have any suitable shape, but one preferred configuration is a flat platform with a power transmission surface on or near the platform on which each wireless power receiver 30 may be placed. can

The wireless power receiver 30 is detachable from the wireless power transmitter 10 , and is generated by the wireless power transmitter 10 when the wireless power receiver 30 is in the vicinity of the wireless power transmitter 10 . It has a secondary coil (32) coupled to the electromagnetic field. In this way, power can be transmitted from the wireless power transmitter 10 to the wireless power receiver 30 without direct electrical contact. At this time, it is said that the main coil 12 and the auxiliary coil 32 are magnetically inductively coupled or resonantly inductively coupled to each other.

The main coil 12 and the auxiliary coil 32 may have any suitable shape, but may be, for example, a copper wire wound around a high permeability formation such as ferrite or an amorphous metal. The auxiliary coil 32 may have a single coil shape or a dual coil shape. Alternatively, the auxiliary coil 32 may include two or more coils.

The wireless power receiver 30 is usually connected to an external load (not shown, also referred to as an actual load of the wireless power receiver), and supplies the wireless power received from the wireless power transmitter 10 to an external load. The wireless power receiver 30 may be carried as a portable electrical or electronic device or an object requesting power, such as a rechargeable battery or battery.

The wireless power receiver 30 of the wireless power transmission system 1 of FIG. 1 further includes a power measuring unit 31 connected to the auxiliary coil 32 .

The power measurement unit 31 generates requested power information 33 indicating the power requested by the wireless power receiver 30 , and transmits it to the control unit 16 . The required power information 33 is control information for controlling the wireless power to be supplied to the wireless power receiver 30 . The wireless power transmission system 1 of FIG. 1 supports a one-way communication method in which control information is transmitted only through a path from the wireless power receiver 30 to the wireless power transmitter 10 .

As an example, the required power information 33 may numerically indicate the amount of power required by the wireless power receiver 30 . For example, when the wireless power receiver 30 requires 10W of power, the power measuring unit 31 may generate the required power information 33 indicating 10W.

The control unit 16 checks the power demand information 33 and generates the control signal 106 so that the power indicated by the power demand information 33 is generated. For example, when the required power information 33 indicates 10W, the control unit 16 generates the control signal 106 so that 10W is transmitted. The electric drive unit 14 receives the control signal 106 to generate an inductive or resonant magnetic field in the vicinity of the main coil 12 and converts it into an AC current signal in the main coil 12 .

The power measuring unit 31 measures the wireless power (or received wireless power) transferred from the main coil 12 to the auxiliary coil 32 due to the AC current signal. The power measured by the power measurement unit 31 is calculated as the difference between the wireless power transferred from the main coil 12 to the auxiliary coil 32 and other losses due to foreign substances such as parasitic loads existing around the system 1 can be

For example, it is assumed that 10W of wireless power is generated from the main coil 12 according to the required power information 33 and transmitted to the auxiliary coil 32 , and 2W of power is lost due to foreign substances. At this time, the power actually delivered to the auxiliary coil 32 (ie, the power actually received by the auxiliary coil 32) is 8W. The power that the auxiliary coil 32 actually receives is called received power, and the received power is a total dissipated in the wireless power receiver due to a magnetic field generated by the wireless power transmitter. is the amount of power

The power measurement unit 31 transmits, to the control unit 16, a received power measurement result (measurement result, 34) reporting the result of performing power measurement by comparing and analyzing the required power and the measured (or actually received) power to the control unit 16 or to provide.

As an embodiment, the power measuring unit 31 may represent a difference value between the required power and the measured power as the received power measurement result 34 . In this case, the received power measurement result 34 indicates 2W.

As another embodiment, the power measurement unit 31 may represent the measured power value itself as the received power measurement result 34 . In this case, the received power measurement result 34 indicates 8W.

As another embodiment, the power measuring unit 31 may represent the received power measurement result 34 in the form of a flag (0 or 1) indicating whether there is a difference between the required power and the measured power. For example, if there is a difference between the required power and the measured power, flag = 1, and if there is no difference, flag = 0 is set. Of course, the opposite is also possible. In the case of the above example, the received power measurement result 34 indicates 1.

As another embodiment, the power measurement unit 31 may determine whether the difference between the required power and the measured power is greater than, equal to, or less than a threshold, and the result of this determination may be expressed as the received power measurement result 34 . there is. For example, if the difference between the required power and the measured power is greater than the threshold, the received power measurement result 34 = 1, and if the difference between the required power and the measured power is less than or equal to the threshold, the received power measurement result 34 = 0 can be set to In the above example, if the threshold is 1W, the lost power 2W is greater than 1W, so the received power measurement result 34 indicates 1. If the difference between the required power and the measured power is greater than the threshold, it means that a foreign object is detected, so that the received power measurement result 34 = 1 has the same meaning as the FOD (foreign object detection) declaration. For example, if the received power measurement result 34 = 1 is continuously maintained and does not change for a predetermined time, it indicates that foreign substances are continuously present, so the wireless power transmitter 10 can stop or block the wireless power transmission. there is.

As another embodiment, if there is a difference between the required power and the measured power, the power measurement unit 31 has the same meaning as the FOD, and provides the received power measurement result 34 indicating this to the control unit 16, If there is no difference, no signal may be provided to the control unit 16 .

When it is determined that a significant parasitic load exists in the vicinity of the wireless power transmitter 10, the control unit 16 receiving the received power measurement result 34 enters a cut-off mode in which the operation of the main coil 12 is reduced or stopped. It is possible to prevent the parasitic load from overheating. Accordingly, the supply of inefficient induction power may be limited or stopped. This is for the foreign matter is detected, the wireless power transmitter 10 is to take action. Alternatively, the power measuring unit 31 may enter a cut-off mode to reduce or stop the driving of the main coil 12 to prevent the parasitic load from generating heat. This means that the wireless power receiver 30 takes action when a foreign material is detected.

As such, the wireless power receiver 30 not only transmits a signal to the wireless power transmitter 10 , but separately includes a power measuring unit 31 to measure the power transmitted from the wireless power transmitter 10 . and compares the measured value with the power value requested by the user, and transmits the result to the wireless power transmitter 10. A one-way power control technique can be provided.

2 illustrates an example of a method for detecting foreign substances by a wireless power receiver using the present invention.

Referring to FIG. 2 , the wireless power receiver 30 generates required power information indicating the power requested by the wireless power receiver 30 ( S200 ).

The wireless power receiver 30 transmits the requested power information to the wireless power transmitter 10 (S205). When the wireless power transmitter 10 generates power in the main coil 12 according to the required power information, the wireless power receiver 30 uses the auxiliary coil 32 to perform magnetic induction or magnetic resonance ( Magnetic resonance) based wireless power is received from the wireless power transmitter 10 (S210).

The wireless power receiver 30 measures the wireless power received in response to the requested power information (S215). At this time, the measured power is the initial wireless power (or required power) transferred from the wireless power transmitter 10 to the wireless power receiver 30 and other losses due to foreign substances such as parasitic loads existing in the vicinity. difference can be calculated.

The wireless power receiver 30 provides the wireless power transmitter 10 with a received power measurement result reporting the result of comparing and analyzing the required power and the measured power (S225).

As an embodiment, the wireless power receiver 30 may represent a difference value between the required power and the measured power as the received power measurement result 34 .

As another embodiment, the wireless power receiver 30 may represent the measured power value itself as the received power measurement result 34 .

As another embodiment, the wireless power receiver 30 may represent a flag form (0 or 1) indicating whether there is a difference between the required power and the measured power as the received power measurement result.

As another embodiment, the wireless power receiver 30 may determine whether the difference between the required power and the measured power is greater than, equal to, or smaller than a threshold, and the result of this determination may be expressed as a received power measurement result.

As another embodiment, if there is a difference between the required power and the measured power, the wireless power receiver 30 provides the wireless power transmitter 10 with a received power measurement result indicating this, and if there is no difference, it transmits no signal to the wireless power It may not be provided to the transmission device 10 . In this case, step S225 may be omitted.

As another embodiment, the wireless power receiver 30 may determine whether the measured power is greater or less than the required power, and may represent this as a received power measurement result. For example, the received power measurement result may be expressed as 'high' or 'low'. ‘high’ indicates that the measured power is greater than the required power, and ‘low’ indicates that the measured power is less than the required power. Alternatively, the received power measurement result may be expressed in three states, such as 'high' or 'low' or 'equal'.

3 illustrates an example of a method for detecting foreign substances by a wireless power transmitter using the present invention.

Referring to FIG. 3 , the wireless power transmitter 10 receives requested power information from the wireless power receiver 30 ( S300 ). In accordance with the required power indicated by the required power information, the wireless power transmitter 10 transmits wireless power to the wireless power receiver 30 based on a magnetic induction or magnetic resonance method (S305).

The wireless power transmitter 10 receives, from the wireless power receiver 30, a received power measurement result that reports the result of the wireless power transmitted according to the required power actually measured by the wireless power receiver 30 (S310) ).

As a result of analyzing the received power measurement result, if it is determined that a foreign material is detected, the wireless power transmitter 10 enters a cut-off mode in which the driving of the main coil 12 is reduced or stopped. As a result, the parasitic load may be prevented from generating heat, and inefficient supply of inductive power may be limited or stopped.

4 illustrates another example of a method for detecting foreign substances by a wireless power transmitter using the present invention.

Referring to FIG. 4 , steps S400 to S410 are performed in the same manner as those of steps S300 to S310, respectively. Meanwhile, step S410 may be limited by the following various embodiments.

As an example, in an embodiment in which the received power measurement result indicates whether the measured power is greater than or less than the required power, the wireless power transmitter 10 indicates 'low' or 'high' It is determined whether the received power measurement result is received N times in the same succession (S415). Here, N represents the number of consecutive 'low' or 'high' reception required for the wireless power transmitter 10 to stop transmitting wireless power, and may be N=2. For example, if the received power measurement result indicating 'low' is continuously received twice in the same way, the wireless power transmitter 10 may stop the power transmission as a measure for detecting foreign substances (S420) . Conversely, even when the received power measurement result indicating 'high' is continuously received twice in the same manner, the wireless power transmitter 10 may stop the power transmission as a measure for detecting foreign substances (S420).

On the other hand, when the reception power measurement result indicating 'low' or 'high' is continuously received less than twice, the wireless power transmitter 10 transmits the wireless power to the wireless power receiver 30 again ( S405). For example, if a reception power measurement result indicating 'low' has been previously received, but a reception power measurement result indicating 'high' is currently received, the same reception power measurement result is not received twice in a row. Therefore, in this case, the wireless power transmitter 10 does not stop the wireless power transmission.

As another example, in an embodiment in which the received power measurement result indicates that there is a difference between the required power and the measured power, the wireless power transmitter 10 equally and continuously repeats the received power measurement result indicating 'there is a difference' When receiving N times, the wireless power transmitter 10 may stop power transmission as a measure for detecting foreign substances ( S420 ).

As another example, in the embodiment in which the received power measurement result is the result of determining whether the difference between the required power and the measured power is greater than, equal to, or smaller than a threshold, the wireless power transmitter 10 is 'large' or 'small' When the received power measurement result indicating ' is received N times in the same succession, the wireless power transmitter 10 may stop the wireless power transmission as a measure for detecting foreign substances ( S420 ).

5 illustrates components of a wireless power transmission system according to another example of the present invention.

Referring to FIG. 5 , the wireless power transmission system 4 includes a wireless power transmitter 40 and at least one wireless power receiver 50 . The wireless power transmitter 40 has a main coil 44 and an electric drive unit 43 connected to the main coil 44 to apply electric drive signals to the main coil 44 to generate an electromagnetic field. A control unit 42 is connected to the electric drive unit 43 . This control unit 42 generates a control signal 45 . The electric drive unit 43 receives the control signal 45 to generate an inductive or resonant magnetic field in the vicinity of the main coil 44 and converts it into an AC current signal in the main coil 44 .

The wireless power transmitter 40 may have any suitable shape, but one preferred configuration is a flat platform with a power transmission surface on or near the platform on which each wireless power receiver 50 may be placed. can

The wireless power receiver 50 is detachable from the wireless power transmitter 40 , and is generated by the wireless power transmitter 40 when the wireless power receiver 50 is in the vicinity of the wireless power transmitter 40 . It has an auxiliary coil (52) coupled with an electromagnetic field. In this way, power can be transferred from the wireless power transmitter 40 to the wireless power receiver 50 without direct electrical contact.

The main coil 44 and the auxiliary coil 52 may have any suitable shape, but may be, for example, a copper wire wound around a high permeability formation such as ferrite or amorphous metal. The auxiliary coil 52 may have a single coil shape or a dual coil shape. Alternatively, the auxiliary coil 52 may include two or more coils.

The wireless power receiver 50 of the wireless power transmission system 4 of FIG. 5 further includes a secondary power measuring unit 51 connected to the auxiliary coil 52 .

The auxiliary power measuring unit 51 generates required power information 53 indicating the power requested by the wireless power receiver 35 , and transmits it to the control unit 42 . The required power information 53 is control information for controlling the power to be supplied to the wireless power receiver 50 .

As an example, the required power information 53 may numerically indicate the amount of power required by the wireless power receiver 50 . For example, when the wireless power receiver 50 requires 10W of power, the power measuring unit 51 may generate the required power information 53 indicating 10W.

The control unit 42 checks the power demand information 53 and generates the control signal 45 so that the power indicated by the power demand information 53 is generated. For example, when the required power information 53 indicates 10W, the control unit 42 generates the control signal 45 so that 10W is transmitted. The electric drive unit 43 receives the control signal 45 to generate an inductive or resonant magnetic field in the vicinity of the main coil 44 and converts it into an AC current signal in the main coil 44 .

Wireless power transmitter 40 further includes a primary power measuring unit (primary power measuring unit, 41). The main power measuring unit 41 measures the power generated in the main coil 44 due to the AC current signal. For example, although the required power information 53 indicates 10W, the power actually generated may be measured as 12W. That is, in order for the power actually received by the wireless power receiver 50 to be 10W according to the indication of the required power information 53 , the main coil 44 generates more than 12W. This can be considered because a 2W loss occurred due to foreign substances such as parasitic loads existing around the system 4 in the process of wireless power being transmitted from the main coil 44 to the auxiliary coil 52 .

The control unit 42 configures (or generates) a measurement report of the generated power 54 indicating the generated power measured by the main power measurement unit 41, and the auxiliary power measurement unit 51 ) is sent to As such, in the wireless power transmission system 4 , the control information 53 may be transmitted through a path from the wireless power receiver 50 to the wireless power transmitter 40 , and the wireless power transmitter 40 receives wireless power. It supports a bidirectional communication scheme in which control information 54 , 55 may be transmitted as a path to the device 50 .

The auxiliary power measuring unit 51 compares and analyzes the difference between the power indicated by the generated power measurement report 54 and the required power, and determines whether to declare a foreign object detection (FOD declaration).

As an embodiment, the auxiliary power measuring unit 51 determines whether the difference between the power indicated by the generated power measurement report 54 and the required power is greater than, equal to, or smaller than a threshold, and the result of this determination is measured for received power. It can be expressed as a measurement result (55). For example, if the difference between the power indicated by the generated power measurement report 54 and the required power is greater than the threshold, the auxiliary power measurement unit 51 sets the received power measurement result 55 = 1, and the generated power measurement report 54 If the difference between the power indicated by ) and the required power is less than or equal to the threshold value, the auxiliary power measuring unit 51 may set the received power measurement result 55 = 0. Alternatively, when the difference between the power indicated by the generated power measurement report 54 and the required power is greater than or equal to the threshold value, the auxiliary power measurement unit 51 sets the received power measurement result 55 = 1, the generated power measurement report ( When the difference between the power indicated by 54) and the required power is smaller than the threshold, the auxiliary power measuring unit 51 may set the received power measurement result 55 = 0. Of course, the values 0 and 1 of the received power measurement result 55 may be interchanged with each other.

For example, let's say the threshold is 1W. As in the above example, in a situation where the power indicated by the generated power measurement report 54 is 12W and the required power is 10W, the difference is 2W, which is greater than the threshold value of 1W. In this case, the received power measurement result 34 indicates 1. If the difference between the power indicated by the generated power measurement report 54 and the required power is greater than a threshold, this may mean that a foreign substance is detected.

In the above description, when the auxiliary power measurement unit 51 declares foreign matter detection, the difference between the power indicated by the generated power measurement report 54 and the required power is compared and analyzed. However, the auxiliary power measurement unit 51 may compare and analyze the difference between the power indicated by the generated power measurement report 54 and the power actually received by the wireless power receiver 50 to declare foreign matter detection. In this case, the method of comparative analysis may be performed in the same manner as the method of comparing and analyzing the difference between the power indicated by the generated power measurement report 54 and the required power.

If the wireless power transmitter 40 transmits a wireless power greater than a certain amount or excessive wireless power compared to the required power (or the power actually received by the wireless power receiver 50) due to a loss due to a foreign substance, the required power is satisfied. , since this reduces the wireless power efficiency, it is desirable to stop or block power transmission by declaring FOD. In this sense, the received power measurement result 55 = 1 may have the same meaning as the FOD declaration. For example, if the received power measurement result 55 = 1 is continuously maintained and does not change for a predetermined time, it means that foreign substances are continuously present, and the wireless power transmitter 40 can stop or block the wireless power transmission. there is.

When it is determined that a significant parasitic load exists in the vicinity of the wireless power transmitter 40, the control unit 42 receiving the received power measurement result 55 enters a cut-off mode in which the driving of the main coil 44 is reduced or stopped. It is possible to prevent the parasitic load from overheating. Accordingly, the supply of inefficient induction power may be limited or stopped. This is for the foreign matter is detected, the wireless power transmitter 40 is to take action. Alternatively, the auxiliary power measuring unit 51 may enter a cut-off mode to reduce or stop the driving of the main coil 44 to prevent the parasitic load from generating heat. This means that the wireless power receiver 50 takes action when a foreign material is detected.

As described above, in the present invention, the wireless power transmitter 40 not only transmits wireless power to the wireless power receiver 50 , but the control unit 42 controls the power generated or transmitted by the wireless power transmitter 40 . It provides a bidirectional power control technology for transmitting the indicated generation power measurement report to the wireless power receiver (50).

6 illustrates components of a wireless power transmission system according to another example of the present invention.

Referring to FIG. 6 , the wireless power transmitter 60 has the same components as the wireless power transmitter 10 of FIG. 1 . On the other hand, the wireless power receiver 70 is compared with the wireless power receiver 30 of FIG. 1 and only further includes a coil 71 for measurement, and the remaining components are the same. The power measuring unit 31 is connected to the measuring coil 71 . The measuring coil 71 may be provided in a shape surrounding the outside of the auxiliary coil 52 , or may be provided inside the auxiliary coil 52 in a shape surrounding the inside of the auxiliary coil 52 .

When a magnetic field or current or voltage is primarily induced in the auxiliary coil 52 by magnetic induction or magnetic resonance between the main coil 12 and the auxiliary coil 52 , the magnetic field or current is secondarily induced in the measuring coil 71 . or voltage is induced. The power measuring unit 31 may measure the received wireless power using a magnetic field, current, or voltage secondary to the measuring coil 71 .

6 illustrates an example in which the measuring coil 71 is additionally configured to the wireless power receiver 60 of FIG. Of course, it may be included.

7 illustrates another example of a method for a wireless power receiver using the present invention to detect a foreign substance.

Referring to FIG. 7 , the wireless power receiver 50 generates required power information indicating the power requested by the wireless power receiver 50 ( S700 ).

The wireless power receiver 50 transmits the requested power information to the wireless power transmitter 40 (S705). When the wireless power transmitter 40 generates power according to the required power information, the wireless power receiver 50 receives the wireless power based on the magnetic induction or resonance induction method from the wireless power transmitter 40 (S710) .

The wireless power receiver 50 receives a generated power measurement report in which the power generated by the wireless power transmitter 40 is measured from the wireless power transmitter 40 (S715). Here, the power generated by the wireless power transmitter 40 does not involve other losses due to foreign substances, and may be different from the wireless power actually received by the wireless power receiver 50 . For example, when other losses due to foreign substances are involved, the wireless power actually received by the wireless power receiver 50 may be measured to be lower than the generated power.

The wireless power receiver 50 compares and analyzes the required power (or the actual received power) and the power indicated by the generated power measurement report to determine whether to declare a foreign substance detection (FOD declaration) (S720).

As an embodiment, the wireless power receiver 50 determines whether the difference between the power indicated by the generated power measurement report and the required power is greater than, equal to, or smaller than a threshold, and displays the result of this determination as a received power measurement result. can For example, if the difference between the power indicated by the generated power measurement report and the required power is greater than the threshold value, the wireless power receiver 50 sets the received power measurement result = 1, and the power indicated by the generated power measurement report and the required power If the difference between them is less than or equal to the threshold value, the wireless power receiver 50 may set the received power measurement result = 0. Alternatively, when the difference between the power indicated by the generated power measurement report and the required power is greater than or equal to the threshold value, the wireless power receiver 50 sets the received power measurement result = 1, and the power and demand indicated by the generated power measurement report When the difference between the powers is smaller than the threshold, the wireless power receiver 50 may set the received power measurement result = 0. Of course, the values 0 and 1 of the received power measurement result indicate may be interchanged.

For example, let's say the threshold is 1W. As in the above example, in a situation where the power indicated by the generated power measurement report is 12W and the required power is 10W, the difference is 2W, which is greater than the threshold value of 1W. In this case, the received power measurement result indicates 1. If the difference between the power indicated by the generated power measurement report and the required power is greater than a threshold, this may mean that a foreign substance is detected.

The wireless power receiver 50 transmits the received power measurement result reporting the result of the comparative analysis to the wireless power transmitter 40 (S725).

8 illustrates another example of a method for detecting foreign substances by a wireless power transmitter using the present invention.

Referring to FIG. 8 , the wireless power transmitter 40 receives requested power information from the wireless power receiver 50 ( S800 ). In accordance with the required power indicated by the required power information, the wireless power transmitter 40 generates wireless power based on the magnetic induction method. That is, the wireless power transmitter 40 checks the required power information and generates a control signal to induce the power indicated by the required power information. For example, when the required power information indicates 10W, the wireless power transmitter 40 generates a control signal so that 10W is transmitted. The wireless power transmitter 40 receives a control signal to generate an induced electromagnetic field in the vicinity of the main coil 44 and converts it into an AC current signal in the main coil 44 .

The wireless power transmitter 40 transmits the generated wireless power to the wireless power receiver 50 (S805).

At this time, the wireless power transmitter 40 measures the power generated in the main coil 44 according to the AC current signal (S810). For example, although the required power information indicates 10W, the actually generated power may be measured as 12W. That is, in order to transmit 10W to the wireless power receiver according to the indication of the required power information, the main coil 44 generates more than 12W. This can be considered because a 2W loss occurred due to foreign substances such as a parasitic load in the process of wireless power being transmitted from the main coil 44 to the auxiliary coil 52 .

The wireless power transmitter 40 constructs a generated power measurement report indicating the measured generated power and transmits it to the wireless power receiver 50 (S815). As such, control information may be transmitted from the wireless power transmitter 40 to the wireless power receiver 50 through a path, and control information is transmitted from the wireless power receiver 50 to the wireless power transmitter 40 through a path. A possible two-way communication method becomes possible.

The wireless power transmitter 40 receives, from the wireless power receiver 50, a received power measurement result, which is a result of comparing and analyzing the required power (or actually received power) and the power indicated by the generated power measurement report (S820). ).

The received power measurement result is information indicating whether a difference between the power indicated by the generated power measurement report and the required power is greater than, equal to, or less than a threshold. For example, if the difference between the power indicated by the generated power measurement report and the required power is greater than the threshold, the auxiliary received power measurement result = 1, and the difference between the power indicated by the generated power measurement report and the required power is greater than the threshold. If it is less than or equal to the received power measurement result = 0 may be set. Or conversely, when the difference between the power indicated by the generated power measurement report and the required power is greater than or equal to the threshold, the received power measurement result = 1 is set, and the difference between the power indicated by the generated power measurement report and the required power is the threshold It may be set to receive power measurement result = 0 at a smaller time. Of course, the values 0 and 1 of the received power measurement result indicate may be interchanged.

For example, let's say the threshold is 1W. As in the above example, in a situation where the power indicated by the generated power measurement report is 12W and the required power is 10W, the difference is 2W, which is greater than the threshold value of 1W. In this case, the received power measurement result indicates 1. If the difference between the power indicated by the generated power measurement report and the required power is greater than a threshold, this may mean that a foreign substance is detected. Accordingly, the wireless power transmitter 40 may recognize this as a foreign matter detection declaration.

As a result of analyzing the received power measurement result, if it is determined that a foreign material is detected, the wireless power transmitter 40 performs an action for detecting the foreign material (S825). For example, the wireless power transmitter 40 may enter a cutoff mode in which the driving of the main coil 12 is reduced or stopped. As a result, the parasitic load may be prevented from generating heat, and inefficient supply of inductive power may be limited or stopped.

9 is an operation flowchart between a wireless power transmitter and a wireless power receiver using the present invention.

Referring to FIG. 9 , the wireless power receiver generates required power information indicating the power requested by the wireless power receiver ( S900 ).

The wireless power receiver transmits the requested power information to the wireless power transmitter (S905). When the wireless power transmitter generates power in the main coil according to the required power information, the wireless power receiver uses the auxiliary coil to transmit wireless power based on magnetic induction or magnetic resonance to the wireless power transmitter. Receive from (S910).

The wireless power receiver measures the received wireless power in response to the requested power information (S915). The power measuring unit may measure the wireless power induced in the secondary coil, or may measure the wireless power secondarily induced from the secondary coil to the measuring coil. At this time, the measured power can be calculated as the difference between the initial wireless power (or required power) transferred from the wireless power transmitter to the wireless power receiver and other losses due to foreign substances such as parasitic loads existing around. .

The wireless power receiver provides the wireless power transmitter with a received power measurement result reporting the result of comparing and analyzing the required power and the measured power (S920).

As an embodiment, the received power measurement result may be defined as a difference value between the required power and the measured power.

As another embodiment, the received power measurement result may be defined as the measured power value itself.

As another embodiment, the received power measurement result may be defined as a flag type (0 or 1) indicating whether there is a difference between the required power and the measured power.

As another embodiment, the received power measurement result may be defined as a result of determining whether a difference between the required power and the measured power is greater than, equal to, or smaller than a threshold.

As another embodiment, the received power measurement result may be defined as information transmitted to the wireless power transmitter only when there is a difference between the required power and the measured power. That is, if there is no difference between the required power and the measured power, the received power measurement result is not transmitted to the wireless power transmitter. In this case, step S920 may be omitted.

As another embodiment, the received power measurement result may be defined as a result of determining whether the measured power is greater than or less than the required power. For example, the received power measurement result may be expressed as 'high' or 'low'. ‘high’ indicates that the measured power is greater than the required power, and ‘low’ indicates that the measured power is less than the required power. Alternatively, the received power measurement result may be expressed in three states, such as 'high' or 'low' or 'equal'.

As a result of analyzing the received power measurement result, if it is determined that a foreign material has been detected, an action for detecting the foreign material is performed (S925). For example, the wireless power transmitter enters a cut-off mode in which the driving of the main coil is reduced or stopped. As a result, the parasitic load may be prevented from generating heat, and inefficient supply of inductive power may be limited or stopped.

Measures for detecting foreign substances in the wireless power transmitter may include the following embodiments. As an example, in an embodiment in which the received power measurement result indicates whether the measured power is greater than or less than the required power, the wireless power transmitter measures the received power indicating 'low' or 'high' It is determined whether the result is received N times consecutively in the same way. Here, N represents the number of consecutive 'low' or 'high' reception required for the wireless power transmitter to stop transmitting wireless power, and may be N=2. For example, if the reception power measurement result indicating 'low' is continuously received twice in the same manner, the wireless power transmitter may stop the power transmission as a measure for detecting foreign substances. Conversely, even when the reception power measurement result indicating 'high' is continuously received twice in the same manner, the wireless power transmitter may stop the power transmission as a measure for detecting foreign substances.

On the other hand, when the reception power measurement result indicating 'low' or 'high' is continuously received less than twice, the wireless power transmitter transmits the wireless power to the wireless power receiver again without considering that foreign matter is detected. can For example, if a reception power measurement result indicating 'low' has been previously received, but a reception power measurement result indicating 'high' is currently received, the same reception power measurement result is not received twice in a row. Therefore, in this case, the wireless power transmitter does not stop the wireless power transmission.

As another example, in an embodiment in which the received power measurement result indicates that there is a difference between the required power and the measured power, when the received power measurement result indicating 'there is a difference' is received N times in the same succession, wireless power The transmitter may stop transmitting power as a measure for detecting foreign substances.

As another example, in the embodiment in which the received power measurement result is the result of determining whether the difference between the required power and the measured power is greater than, equal to, or smaller than a threshold, the wireless power transmitter indicates 'large' or 'small' When receiving the same received power measurement result N times consecutively, the wireless power transmitter may stop the wireless power transmission as a measure for detecting foreign substances.

All of the above-described functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, an ASIC (Application Specific Integrated Circuit), etc. according to software or program codes coded to perform the functions. The design, development and implementation of the above code will be apparent to those skilled in the art based on the description of the present invention.

Although the present invention has been described with reference to embodiments, those of ordinary skill in the art can variously modify and change the present invention within the scope without departing from the technical spirit and scope of the present invention. You will understand. Therefore, the present invention is not limited to the above-described embodiments, and it will be said that all embodiments within the scope of the following claims are included.

Claims (8)

In the wireless power receiver for detecting foreign substances,
a secondary coil configured to receive wireless power from a primary coil of the wireless power transmitter; and
a power measurement unit configured to generate required power information indicating power required by the wireless power receiver, transmit the required power information to the wireless power transmitter, and measure the received wireless power,
the power measuring unit is further configured to generate a received power measuring result indicating whether or not a foreign matter has been detected;
the power measuring unit determines the received power measurement result based on a difference value between the measured received wireless power and the required power information compared with a threshold for a predetermined time;
The power measuring unit transmits the received power measurement result to the wireless power transmitter, a wireless power receiver for detecting foreign substances. The method of claim 1,
The reception power measurement result includes a flag indicating whether there is a difference value between the required power information and the measured received wireless power. In the wireless power receiving method of the wireless power receiving device for detecting foreign substances,
generating required power information indicating power required by the wireless power receiver;
transmitting the requested power information to a wireless power transmitter;
receiving wireless power by a secondary coil from a primary coil of the wireless power transmitter;
measuring the received wireless power;
To generate a received power measurement result indicating whether or not foreign matter is detected - the received power measurement result is based on a difference value between the measured received wireless power and the required power information compared with a threshold for a predetermined time step; and
Transmitting the received power measurement result to the wireless power transmitter
A wireless power receiving method comprising a. 4. The method of claim 3,
The reception power measurement result includes a flag indicating whether there is a difference value between the required power information and the measured received wireless power. In the wireless power transmission device for detecting foreign substances,
a control configured to receive required power information indicating power required by the wireless power receiver from the wireless power receiver, generate a control signal for providing the requested power, and transmit the control signal to the electric driving unit unit;
the electric drive unit configured to apply an electric drive signal to a primary coil in response to the control signal; and
the first coil connected to the electric drive unit, wherein the first coil is configured to transmit wireless power to a secondary coil of the wireless power receiver;
including,
the control unit receives, from the wireless power receiver, a reception power measurement result indicating whether or not foreign matter is detected;
The received power measurement result is based on a difference value between the measured received wireless power and the required power information compared to a threshold for a predetermined time, a wireless power transmitter for detecting foreign substances. 6. The method of claim 5,
When the received power measurement result indicates that foreign substances are present, the control unit stops the transmission of the wireless power from the first coil, a wireless power transmitter for detecting foreign substances. In the wireless power transmission method of the wireless power transmission device for detecting foreign substances,
Receiving power demand information indicating power required by the wireless power receiver from the wireless power receiver;
generating and providing an electric driving signal to a first coil (primary coil) of the wireless power transmitter to provide the required power;
transmitting wireless power generated from the first coil to the wireless power receiver including a second coil in response to the electric driving signal; and
Receiving a reception power measurement result indicating whether or not foreign matter is detected from the wireless power receiver
including,
The received power measurement result is based on a difference value between the measured received wireless power and the required power information compared with a threshold for a predetermined time, the wireless power transmission method. 8. The method of claim 7,
The reception power measurement result includes a flag indicating whether there is a difference value between the required power information and the measured received wireless power.

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