JP5404836B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device in which an inverter that converts DC power into AC power and an electric motor driven by AC power converted by the inverter are integrated.

In recent years, in order to increase the output of an internal combustion engine, a vehicle provided with a supercharger driven by an electric motor on an intake passage, or a vehicle driven by an electric motor such as an electric vehicle has been developed.
In addition, a power conversion device in which an electric motor and an inverter are integrated has been proposed in order to reduce the size and improve the mountability.

  When driving the power converter, the switching element and the motor coil generate heat due to the large current required at the time of driving, and the heat generating parts are concentrated in an integrated structure, so that the power converter operates in a short time. The limit temperature may be reached.

For example, Patent Document 1 describes a power conversion device in which one of bus bars connected to a switching element is brought into contact with an electrically insulating lubricating oil used for a motor bearing, a gear mechanism or the like, and the switching element is cooled. Yes.
Further, for example, Patent Document 2 describes a motor unit in which a power line from an inverter is connected to an electric motor via a terminal block, a protrusion is provided on the terminal block, and a coolant is allowed to flow inside the protrusion to cool the motor unit. ing.

JP 2009-273276 A JP 2010-268633 A

However, since the power conversion device of Patent Document 1 is cooled using lubricating oil, lubricating oil piping is required, and the device is increased and complicated due to the oil-tight structure of the housing. there were.
Further, the motor unit of Patent Document 2 has a problem that the cooling efficiency of the switching element and the coil of the electric motor is low because the nearby parts are cooled by cooling the terminal block.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to obtain a power conversion device that can cool an electric motor body and an inverter efficiently with a simple configuration.

The power converter according to the present invention includes an inverter that converts DC power into AC power, an electric motor body that is driven by the AC power converted by the inverter, and an AC that electrically connects the inverter and the electric motor body. An output bus bar, a power bus bar electrically connected to the inverter and a DC power source, and a housing that houses the inverter and the electric motor body and has heat radiation fins on the outside.
The inverter has a substrate disposed on one side of the electric motor body in the axial direction, and a plurality of switching elements mounted on the surface of the substrate opposite to the electric motor body side,
By fastening the board and the housing by the fastening member provided penetrating the outer peripheral part of the board and the housing, each end of the AC output bus bar and the power bus bar on the surface of the board on the motor body side And a power converter in which the switching element is electrically connected,
The fastening member penetrates through each of the one end portions of the AC output bus bar and the power bus bar, and its tip portion projects to the refrigerant flow path between the heat radiating fins.

  According to the power conversion device according to the present invention, the fastening member penetrating each one end of the AC output bus bar and the power bus bar protrudes to the refrigerant flow path between the radiating fins of the fastening member. Since the cooling medium flowing through the refrigerant flow path is in direct contact, the inverter and the electric motor main body are efficiently cooled with a simple configuration.

It is a sectional side view which shows schematic structure of the power converter device which concerns on Embodiment 1 of this invention. It is a top view which shows the inverter of FIG. It is a perspective view when the housing of FIG. 1 is seen from the electric motor main body side. It is an example different from the radiation fin of FIG. 1, Comprising: It is a perspective view when a housing is seen from the electric motor main body side. It is a top view which shows the modification of the inverter of FIG. It is a sectional side view which shows schematic structure of the power converter device which concerns on Embodiment 2 of this invention. It is a perspective view when the housing of FIG. 6 is seen from the electric motor main body side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or equivalent members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a side sectional view showing a schematic configuration of a power converter according to Embodiment 1 of the present invention, FIG. 2 is a plan view showing the inverter of FIG. 1, and FIG. 3 is a plan view showing the housing 2 of FIG. It is a perspective view when it sees.
The power converter 1 includes an inverter 10 that converts DC power into AC power, an electric motor body 6 that is driven by the AC power converted by the inverter 10, and an AC that electrically connects the inverter 10 and the electric motor body 6. Output bus bars 3U, 3V, 3W, power supply bus bars 3P, 3N electrically connected to an inverter 10 and a DC power supply (not shown), and a housing 2 housing the inverter 10 and the electric motor body 6 are provided.

The housing 2 has a hollow portion for housing the electric motor main body 6, and a plurality of radiating fins 21 whose front end portions extend in a direction perpendicular to the substrate 13 of the inverter 10 stand on the outer periphery thereof. Moreover, the board | substrate 13 of the inverter 10 is joined with the housing 2 through the inside via the heat dissipation sheet | seat 14 which is an electrically insulating heat dissipation member which has the heat conductivity of 1 W / m * K or more. A cover 23 that covers the inverter 10 is fixed to one side of the housing 2 with screws 24.
Note that there is a gap between the outer peripheral end surface of the substrate 13 and the inner wall surface of the housing 2, and an air layer is interposed.

The electric motor body 6 is a three-phase AC motor, and a stator core 61 formed by laminating electromagnetic steel plates is fixed to the inner wall surface of the housing 2. A slot is formed in the stator core 61, and a coil 62 of each phase is wound around the slot.
A rotor 63 fixed to a shaft 65 is provided inside the stator constituted by the stator core 61 and the coil 62. The rotor 63 is rotatably supported by bearings 64 provided at both ends of the shaft 65. A rotating body (not shown) is fixed to the end of the shaft 65, and the shaft 65 and the rotating body are rotated and driven together with the coil 62 by the rotating magnetic field of the stator generated by the current flowing in the coil 62.

  On one side surface of the stator, the connection plate 4 is fitted and disposed on the step portion 22 of the housing 2 from the substrate 13 side. The connection plate 4 is formed by insert-molding laminated coils 62 of respective phases with an insulating resin material. One end of each phase coil 62 is connected by welding within the connection plate 4 as a neutral point, and the other end is bent into an L-shape of AC output bus bars 3U, 3V, 3W. One end A is electrically connected by welding.

In this connection plate 4, stoppers 41 having internal threads formed therein are embedded at seven positions at intervals on the outer peripheral side edge in the circumferential direction. Bolts 5U, 5V, 5W, 5P, and 5N, which are fastening members for fastening the housing 2 and the substrate 13, are screwed to the stoppers 41.
Bolts 5U, 5V, 5W penetrate through one end of AC output bus bars 3U, 3V, 3W. Further, the bolts 5P and 5N penetrate through one end portions of the positive power supply bus bar 3P and the negative power supply bus bar 3N, respectively.
Each of the bolts 5U, 5V, 5W, 5P, 5N has an end portion extending to an air flow path that is a refrigerant flow path between the radiation fins 21.
Here, the bus bars 3U, 3V, 3W, 3P, 3N are formed of copper or the like having high thermal conductivity, and their respective end portions are exposed on the surface of the connection plate 4, and the exposed portions are phosphor bronze, aluminum, or the like. In contact with the circumferential end surface of the stopper 41 made of a material having a thermal conductivity of 100 W / m · K or more.

The inverter 10 is a three-phase inverter. In this inverter, the U-phase upper arm side switching element 11U, the U phase lower arm side switching element 12U, and the V phase are disposed on the surface (surface) opposite to the electric motor body 6 of the disk-shaped substrate 13 and on the peripheral side thereof. Six switching elements of an upper arm side switching element 11V, a V phase lower arm side switching element 12V, a W phase upper arm side switching element 11W, and a W phase lower arm side switching element 12W are arranged.
Due to the fastening force of the bolts 5U, 5V, and 5W, the surface (rear surface) of the substrate 13 on the motor body 6 side and the surface of the connection plate 4 are in surface contact. As a result, the upper arm side switching elements 11U, 11V, 11W and the lower arm side switching elements 12U, 12V, 12W of each phase are electrically connected to the AC output bus bars 3U, 3V, 3W of the respective phases on the back surface of the substrate 13. Has been.
A positive power supply bus bar 3P is fastened to the surface of the substrate 13 with a bolt 5P between the V-phase upper arm switching element 11V and the W-phase upper arm switching element 11W.

A negative power source bus bar 3N is fastened to the surface of the substrate 13 with bolts 5N in the vicinity of the V-phase lower arm side switching element 12V.
A connection terminal 51P is provided at the end of the positive power supply bus bar 3P, and a connection terminal 51N is provided at the end of the negative power supply bus bar 3N. These connection terminals 51P and 51N are electrically connected to a DC power source (not shown).
In addition, a negative power supply bar 3N is fastened to the back surface of the substrate 13 with a bolt 5N in the vicinity of the U-phase lower arm side switching element 12U and the W phase lower arm side switching element 12W.

In FIG. 2, a thick dotted line indicates a state in which the current of each phase input from the positive power supply bus bar 3P flows to the coil 62 of each phase, and a thin dotted line indicates that the current from the coil 62 of each phase flows in the negative power supply bus bar 3N. It shows how it flows.
For example, the U-phase current input from the positive power supply bus bar 3P flows through the U-phase upper arm side switching element 11U and the AC output bus bar 3U and flows to the U-phase coil 62 of the stator. Thereafter, the U-phase current flows to the negative power supply bus bar 3N through the AC output bus bar 3U, the U-phase lower arm switching element 12U, and the outer peripheral edge of the substrate 13.

  The upper arm side switching elements 11U, 11V, and 11W and the lower arm side switching elements 12U, 12V, and 12W are P-channel MOSFETs and IGBTs, and the number of switching elements in parallel increases or decreases according to the amount of power.

According to the power conversion device according to this embodiment, the bolts 5U, 5V, 5W, 5P, 5N, which are fastening members penetrating each one end of the AC output bus bars 3U, 3V, 3W and the power bus bars, 3P, 3N, The tip portion projects to the air flow path between the radiating fins 21, and the bolts 5U, 5V, 5W, 5P, and 5N are in direct contact with cooling air that is a cooling medium.
Therefore, the AC output bus bars 3U, 3V, 3W, the power supply bus bars 3P, 3N, the stopper 41, and the substrate 13 connected to the bolts 5U, 5V, 5W, 5P, 5N are cooled, and the AC output bus bars 3U, 3V, The switching elements 11U, 11V, 11W, 12U, 12V, and 12W connected to 3W and connected to the substrate 13 are prevented from being heated.
Further, heat generation of the coil 62 of the electric motor main body 6 connected to the AC output bus bars 3U, 3V, 3W is also suppressed.

  Further, according to this embodiment, the AC output bus bars 3U, 3V, 3W are arranged between the upper arm side switching elements 11U, 11V, 11W and the lower arm side switching elements 12U, 12V, 12W. That is, since it is arranged between both heat sources, these heats are efficiently released to the outside through the bolts 5U, 5V, 5W.

  The positive power bus bar 3P is disposed in the vicinity of the upper arm side switching element 11V and the upper arm side switching element 11W electrically connected to the power bus bar 3P, and the negative power bus bar 3N Since it is arranged in the vicinity of the lower arm side switching element 12V and the upper arm side switching element 11U that are electrically connected to the power bus bar 3N, the upper arm side switching element 11V, the upper arm side switching element 11W, and the lower arm side switching The heat of the element 12V and the upper arm side switching element 11U is efficiently released to the outside through the bolts 5P and 5N.

  Further, since the bolts 5U, 5V, 5W, 5P, 5N pass through the peripheral edge of the connection plate 4 formed of an insulating material, the bolts 5U, 5V, 5W, 5P, 5N and the housing 2 are interposed between them. Electrical insulation is ensured.

  The bolts 5U, 5V, 5W, 5P, and 5N and the stoppers 41 to which the bolts 5U, 5V, 5W, 5P, and 5N are screwed are formed of a material having a thermal conductivity of 100 W / m · K or more. In addition, since the end face of the cylindrical stopper 41 and the bus bars 3U, 3V, 3W, 3P, 3N are in surface contact with each other, the cross-sectional area of the heat conduction path is increased accordingly, and the heat radiation efficiency is increased.

  Further, since the housing 2 and the substrate 13 are fastened by bolts 5U, 5V, 5W, 5P, 5N through an electrically insulating heat dissipation sheet 14 having a thermal conductivity of 1 W / m · K or more, the substrate The heat from 13 is efficiently transferred to the housing 2.

  Further, in the regions of the switching elements 11U, 11V, 11W, 12U, 12V, and 12W, the circumferential distances between the adjacent bolts 5U, 5V, 5W, 5P, and 5N are substantially equal. It is possible to prevent the temperature distribution from being biased.

  Further, since the tips of the plurality of bolts 5U, 5V, 5W, 5P, and 5N extend in the direction perpendicular to the substrate 13 in the same manner as the radiation fins 21, the refrigerant flow paths between the radiation fins 21 An increase in flow resistance can be suppressed.

  In the above embodiment, the radiating fins 21 of the housing 2 have tips extending in the direction perpendicular to the substrate 13. However, as shown in FIG. It may be parallel.

The bolt 5N has the housing 2 as the common ground with the inverter 10, and a stopper (not shown) is formed in the housing 2, so that the negative power bus bar 3N can be omitted as shown in FIG. As a result, the connection plate 4 can be simplified.
In addition, the thick dotted line and the thin dotted line in FIG. 5 are the same as those shown in FIG. 2, and the thick dotted line indicates that the current of each phase input from the positive power supply bus bar 3 </ b> P flows through the coil 62 of each phase. The thin dotted line shows how the current from the coil 62 of each phase flows to the negative power supply bus bar 3N.

Embodiment 2. FIG.
6 is a side sectional view showing a schematic configuration of a power conversion device according to Embodiment 2 of the present invention, and FIG. 7 is a perspective view when the housing 2 of FIG. 6 is viewed from the motor body 6 side.
In this embodiment, the plurality of radiating fins 21 </ b> B are radially outward of the electric motor body 6 and extend in the radial direction at intervals along the axis.
Each bolt 5U, 5V, 5W, 5P, 5N has its tip portion penetrating through the radiation fin 21B.
Other configurations are the same as those of the power conversion apparatus according to the first embodiment.

  In this embodiment, the same effect as in the first embodiment can be obtained, and by disposing the radiating fins 21 </ b> B around the motor main body 6, the motor main body can be compared with the power conversion device in the first embodiment. The heat from 6 can be released to the outside more efficiently.

It should be noted that a flow path cover surrounding the outer periphery of the heat radiation fins 21, 21A, 21B of each embodiment is provided, and the cooling air is efficiently guided to the heat radiation fins 21, 21A, 21B by the flow path cover. Good.
In each of the above embodiments, the case where cooling air is used as the cooling medium has been described. However, the present invention can be applied even if the cooling medium is cooling water.

  DESCRIPTION OF SYMBOLS 1 Power converter, 10 Inverter, 11U, 11V, 11W Upper arm side switching element, 12U, 12V, 12W Lower arm side switching element, 13 Substrate, 14 Heat radiation sheet (heat radiation member), 2 Housing, 21, 21A, 21B Heat radiation Fin, 22 Stepped portion, 23 Cover, 24 Screw, 3U, 3V, 3W AC output bus bar, 3P, 3N Power bus bar, 4 Connection plate, 41 Stopper, 5U, 5V, 5W, 5P, 5N Bolt (fastening member), 6 Motor body, 61 Stator core, 62 Coil, 63 Rotor, 64 Bearing, 65 Shaft.

Claims (11)

An inverter for converting DC power into AC power, an electric motor body driven by the AC power converted by the inverter, an AC output bus bar electrically connecting the inverter and the electric motor body, the inverter and the DC power source A power bus bar electrically connected to each other, and a housing that houses the inverter and the electric motor main body and has heat radiation fins on the outside,
The inverter has a substrate disposed on one side of the electric motor body in the axial direction, and a plurality of switching elements mounted on the surface of the substrate opposite to the electric motor body side,
By fastening the board and the housing by the fastening member provided penetrating the outer peripheral part of the board and the housing, each end of the AC output bus bar and the power bus bar on the surface of the board on the motor body side And a power converter in which the switching element is electrically connected,
The said fastening member penetrates each said one end part of the said alternating current output bus bar and the said power supply bus bar, and the front-end | tip part protrudes to the refrigerant | coolant flow path between the said radiation fins, The power converter device characterized by the above-mentioned.   The power converter according to claim 1, wherein the AC output bus bar is disposed between an upper arm side switching element and a lower arm side switching element of the switching elements.   The power bus bar has a positive side disposed in the vicinity of the upper arm side switching element among the switching elements, and a negative side disposed in the vicinity of the lower arm side switching element among the switching elements. The power conversion device according to claim 1 or 2.   The circumferential distance between the adjacent fastening members is substantially equal in a plurality of the switching element regions arranged along the circumferential direction on the outer peripheral edge of the substrate. 4. The power conversion device according to claim 1. Between the electric motor main body and the substrate, a connection plate formed of an insulating material and electrically connecting the coil of the electric motor main body and the other end of the AC output bus bar is provided,
5. The power conversion device according to claim 1, wherein the fastening member penetrates a peripheral edge portion formed of the insulating material. The peripheral portion is provided with a high thermal conductivity stopper with a female thread formed thereon,
The fastening member is screwed to the stopper,
The power converter according to claim 5, wherein an end surface of the stopper is in surface contact with one end of each of the AC output bar and the power bus bar.   The electrical insulation heat radiating member which has a heat conductivity of 1 W / m * K or more is interposed between the housing and the substrate. The power converter described.   The power converter according to claim 6, wherein the fastening member and the stopper are made of a material having a thermal conductivity of 100 W / m · K or more.   The power converter according to any one of claims 1 to 8, wherein tip ends of the plurality of heat radiating fins extend in a direction perpendicular to the substrate in the same manner as the fastening member. The plurality of the heat radiating fins each have a tip portion extending in parallel to the substrate,
The power converter according to any one of claims 1 to 8, wherein tip ends of the plurality of fastening members each extend in a direction perpendicular to the substrate. The plurality of heat dissipating fins are radially outward of the electric motor body and extending in the radial direction at intervals along the axis thereof,
The power conversion according to any one of claims 1 to 8, wherein the plurality of fastening members have tip portions extending in a direction perpendicular to the substrate and penetrating through the radiating fins. apparatus.

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