JP2004088983A - Rotary electric machine mounting inverter and circuit device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary electric machine mounting an inverter exhibiting excellent mountability on a vehicle while ensuring good cooling performance of both a smoothing capacitor and a semiconductor switching element. <P>SOLUTION: A smoothing capacitor 11 and semiconductor switching elements 4 and 5 are mounted, respectively, on the motor side main surface 32 and the anti-motor side main surface 33 of a heat sink 30 disposed in proximity to one axial direction of the motor body 2 and having main surfaces 32 and 33 extending substantially in the radial direction. A small and lightweight rotary electric machine mounting an inverter can thereby be realized. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotating electric machine mounted with an inverter and a circuit device suitable for the same, and more particularly to a rotating electric machine mounted with an inverter for a vehicle and a circuit device suitable for the same.
[0002]
[Prior art]
In recent years, despite the fact that the power source of a vehicle motor is a battery, that is, a DC power source, the adoption of an AC machine (synchronous machine) as a vehicle motor from the viewpoint of reliability, controllability, efficiency, etc. due to advances in semiconductor technology. It is becoming mainstream.
[0003]
In this case, an inverter circuit for converting DC power to three-phase AC power for driving the motor (or regenerative power generation) is required. However, if the wiring resistance or wiring inductance between the inverter circuit and the motor is large, power loss occurs. Because many disadvantages such as heat generation, electromagnetic noise, and weight increase occur, it has been proposed in Japanese Patent Application Laid-Open No. H11-163, for example, to directly mount this inverter circuit on a motor.
[0004]
[Patent Document 1] JP-A-5-292703
The inverter-mounted rotary electric machine disclosed in this publication has an inverter circuit disposed at a position axially adjacent to a motor body, and a heat sink (cooling body in the present invention) is provided between the inverter device and the motor body. Thus, an effect can be obtained that heat generated by the motor main body hardly affects the semiconductor switching elements constituting the inverter circuit.
[0006]
In addition, the motor itself becomes extremely hot, and the inverter circuit integrally mounted on the motor body also generates a large amount of heat. Therefore, a heat sink is required to protect the semiconductor switching elements constituting the inverter device from destruction and damage. The above publication also discloses that the motor body is liquid cooled.
[0007]
Patent Document 2 below discloses a fixed inverter type motor in which a case with a built-in inverter device is mounted on an outer surface of an end frame of the motor in connection with the present invention.
[0008]
[Patent Document 2] JP-A-11-164521
[Problems to be solved by the invention]
However, in this type of inverter device, a smoothing capacitor for reducing a ripple current together with a semiconductor switching element forming a multiphase inverter circuit is an essential component, but the smoothing capacitor through which a ripple current generated by high-frequency switching flows has a high temperature. This causes problems such as shortened life and reduced insulation. Therefore, in a conventional inverter device, it is usual that this smoothing capacitor as well as the semiconductor switching element is cooled by being in close contact with a heat sink.
[0010]
In the circuit component arrangement of the above publication, the inverter device is arranged on the main surface of the heat sink on the side opposite to the motor (the main surface on the opposite side in the axial direction with respect to the motor body). In close contact with the main surface on the side opposite to the motor.
[0011]
However, in a rotary electric machine equipped with an inverter employing such a smoothing capacitor arrangement, a large-sized smoothing capacitor requiring a large installation area is arranged on the side of the inverter circuit, so that the main surface area of the heat sink increases. As a result, the radial and circumferential lengths (the area perpendicular to the axial direction) of the inverter device and the heat sink increase, and the space and weight of the inverter device and the heat sink increase as a whole.
[0012]
In order to solve this problem, a conventionally known two-story type inverter device can be adopted. In this two-story type inverter device, a semiconductor switching element having relatively higher cooling importance is mounted on a heat sink, and a smoothing capacitor is mechanically supported above the semiconductor switching element, that is, in a direction away from the heat sink. That is. Of course, since the smoothing capacitor must also be cooled, the heat sink and the smoothing capacitor can be thermally coupled well (for example, a good heat conducting member can be interposed, or the heat sink can penetrate between the semiconductor switching elements to smooth the smoothing capacitor). Side projections). By doing so, the weight and the physique of the heat sink and the entire inverter device can be reduced as a whole. Further, as compared with the one-plane arrangement method of the above publication, the connection wiring distance between the semiconductor switching element and the smoothing capacitor is easily reduced, so that the inductance of the connection wiring is reduced, and the high-frequency switching noise voltage is reduced. The effect of reducing the size of the smoothing capacitor can be expected.
[0013]
However, since this method requires a considerable gap between the semiconductor switching element and the smoothing capacitor as described above, the axial length of the rotary electric machine equipped with an inverter is abnormally increased, and the vehicle of this rotary electric machine In addition to the troublesome problem that the mountability of the smoothing capacitor deteriorates, it has not been easy to fundamentally solve the problem that the cooling performance of the smoothing capacitor deteriorates as described above.
[0014]
In addition, the motor with an inverter device disclosed in Patent Document 2 discloses that a case of the inverter device including a large-sized smoothing capacitor is fixed to an outer end surface of an end frame. In such a structure, a switching device constituting the inverter device is disclosed. There is a problem that cooling of the element, the smoothing capacitor, and the control microcomputer (controller) is not easy.
[0015]
The present invention has been made in view of the above problems, and provides an inverter-mounted rotary electric machine and a circuit device suitable for the same, which ensure excellent cooling performance of both the smoothing capacitor and the semiconductor switching element and also have excellent vehicle mountability. Its purpose is to provide.
[0016]
[Means to solve the problem]
The rotating electric machine with the inverter according to the present invention is configured such that power is transferred between a DC power source fixed to one axial side of the motor main body and a stator coil of the motor main body. And a predetermined number of semiconductor switching elements that constitute an inverter circuit that performs orthogonal transformation and is interposed between the DC power supply and the stator coil, and an inverter device that controls the inverter circuit. Inverter having a smoothing capacitor connected between a pair of DC terminals to reduce switching noise of the inverter circuit, and a cooling body in contact with the semiconductor switching element and the smoothing capacitor to cool the semiconductor switching element and the smoothing capacitor. In mounted rotary electric machines,
The smoothing capacitor is fixed to a motor-side main surface on a side facing the motor main body among a pair of main surfaces of the cooling body extending in a radial direction, and the semiconductor switching element includes the pair of cooling bodies. Are fixed to a main surface on the side opposite to the motor main body that does not face the motor main body.
[0017]
That is, the present invention uses a cooling body (heat sink) by using both the main surface on the motor body side of the cooling body as a heat sink extending in the radial direction as a semiconductor switching element cooling surface and a smoothing capacitor cooling surface as circuit components. ), The semiconductor switching element and the smoothing capacitor can be cooled well, and the gap between the semiconductor switching element and the smoothing capacitor can be omitted compared to the above two-story inverter device structure. The axial length of the electric machine can also be reduced, and the smoothing condenser can be firmly fixed to the cooling body, so the vibration resistance required for the vehicle is improved, and ultimately the physique, weight, and vehicle mountability are excellent. A rotating electric machine with an inverter can be realized.
[0018]
As a technical idea similar to the present invention, a semiconductor switching element may be mounted on the main surface of the cooling body on the motor body side, and a smoothing capacitor may be fixed on the non-motor side main surface. However, in this case, the temperature of the semiconductor switching element, which requires the best cooling performance, is susceptible to the heat generated by the motor body through the heat propagation path of conduction, convection, and radiation. Disadvantage.
[0019]
That is, according to the present invention, the semiconductor switching element can be arranged with both the cooling body and the smoothing capacitor separated from the motor body as a heating element or a high-temperature element. The effect of the heat generated by the motor body can also be reduced.
[0020]
The cooling body may have any shape as long as it has at least a pair of main surfaces extending substantially in the radial direction, and may be air-cooled or liquid-cooled.
[0021]
In a preferred aspect, the inverter device includes a first conductor closely attached to the main surface of the cooling body on the side opposite to the motor via an electrical insulator, and the semiconductor switching element mounted on the first conductor. And an upper arm element of the inverter circuit. With this configuration, the semiconductor switching element forming the upper arm element can be satisfactorily cooled.
[0022]
In a preferred embodiment, the first conductor forms a high-voltage line (high-order DC power supply line) connected to a high-order power supply end of a power supply smoothing capacitor (hereinafter, also simply referred to as a smoothing capacitor). By doing so, the wiring structure can be simplified.
[0023]
In a preferred aspect, the inverter device is configured such that the inverter circuit includes a second conductor directly in contact with the opposite main surface of the cooling body on the side opposite to the motor, and the semiconductor switching element mounted on the second conductor. And a lower arm element. With this configuration, the semiconductor switching element forming the lower arm element can be satisfactorily cooled.
[0024]
In a preferred aspect, the second conductor forms an AC output line of an inverter circuit connected to a lead of the stator coil. By doing so, the wiring structure can be simplified.
[0025]
In a preferred aspect, the inverter device includes a control microcomputer that contacts a main surface of the cooling body on the side opposite to the motor to output information on a state of the inverter circuit to the outside. This makes it possible to suitably cool the control microcomputer of the inverter device. It is to be noted that the control microcomputer can be in contact with the cooling body via some kind of good heat conductive member.
[0026]
In a preferred aspect, the cooling body has a groove having an opening in the motor-side main surface to form a cooling fluid flow path, and the smoothing capacitor is fixed to the motor-side main surface of the cooling body. The opening of the groove is closed. With this configuration, even when the cooling body has a liquid cooling structure having a cooling fluid passage therein, the smoothing condenser can be favorably cooled with a simple structure. The details will be described below.
[0027]
When a cooling fluid passage is provided inside a cooling body, it is necessary to form the cooling fluid passage in a closed structure except for its inlet and outlet. In a conventionally known ordinary method of providing a cooling medium passage having such a closed structure, it is the simplest structure to provide a groove having an opening on one main surface of a cooling body and close this one main surface with a cover plate or the like. Become.
[0028]
However, even in the case of a cooling body having a cooling medium passage having a closed structure, it is necessary to add a structure and a manufacturing process in which a cover plate is manufactured and fixed to a main body of the cooling body. Since the cover plate is interposed in the cooling heat transfer passage of the smoothing condenser, there is a problem that the cooling performance of the smoothing condenser is reduced.
[0029]
On the other hand, according to this embodiment, a structure is employed in which the opening of the groove portion of the cooling fluid is directly closed by the smoothing condenser without using the above-mentioned lid plate. Of course, in this case, a fixing step between the smoothing condenser and the cooling body is required, but even when a cover plate is used, a step of fixing both of them for good thermal contact between the cover plate and the smoothing condenser is necessary. It is the same because there is. More specifically, the cooling body with the cooling fluid passage has a heat sink function and a liquid cooling function for the switching element of the inverter circuit. The heat sink function is most preferably a metal block portion having good thermal conductivity, and this metal block portion is arranged as close to the switching elements as possible to reduce the thermal resistance between them, thereby reducing the heat sink function, that is, the switching element. It is preferable that the temporary large heat generation be better absorbed by the heat capacity of the metal block portion. Although the cover plate also has the heat sink function similarly to the metal block portion, the cover plate has to receive heat from the switching device through the partition wall portion of the cooling body that defines the groove as the cooling fluid passage. The heat sink function is much lower than that of the metal block adjacent to the metal block.
[0030]
Therefore, if the cover plate is omitted, and the thickness of the portion of the cooling body closer to the switching element than the metal block portion, that is, the groove portion is increased by the thickness thereof, the cooling body without the cover plate has the cover plate. The heat sink function, i.e., the transient heat absorption function, can be improved without changing the total thickness of the heat sink as compared with the heat sink of the present invention.
[0031]
9. The circuit device according to claim 8, wherein the heat sink has a pair of main surfaces parallel to each other, a capacitor fixed to one main surface of the heat sink, and a circuit unit fixed to the other main surface of the heat sink. Wherein the heat sink has a groove having an opening on the one main surface of the heat sink to form a cooling fluid flow path, and the capacitor is fixed to the one main surface of the heat sink. The opening of the groove is closed.
[0032]
According to the present invention, it is possible to realize a circuit device capable of satisfactorily cooling a circuit section and a capacitor, despite the simple structure, for the reasons described above.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
A preferred embodiment of the inverter-equipped rotating electric machine of the present invention as a vehicle rotating electric machine that generates running power will be described with reference to the following examples.
(Example 1)
(Circuit explanation)
The circuit of the rotary electric machine equipped with an inverter will be described with reference to the circuit diagram shown in FIG.
[0034]
1 is a battery, 2 is a motor body composed of a three-phase synchronous machine, and 3 is an inverter device. The inverter device 3 performs an orthogonal transformation operation between the battery 1 and the motor body 2 to connect the battery 1 and the motor body 2 with each other. Power transfer between the two.
[0035]
The inverter device 3 includes a three-phase inverter circuit 10 having semiconductor switching elements 4 to 9 composed of MOS transistors, a smoothing capacitor 11, a current sensor 12, and a gate controller 13 as a control microcomputer. The information of the inverter device 3 is output to the external controller 14, and the three-phase inverter circuit 10 is intermittently controlled based on the torque command from the controller 14 and the current measurement value from the current sensor 12 to control the motor body 2.
[0036]
The smoothing capacitor 11 absorbs voltage fluctuations caused by the intermittent switching of the semiconductor switching elements 4 to 9, suppresses potential fluctuations in the DC lines 15 and 16, and reduces adverse effects on the battery 1 and radiation of electromagnetic noise. Reference numeral 17 denotes a conductor line connecting the positive terminal of the smoothing capacitor 11 and the high-side DC line 15, and reference numeral 18 denotes a conductor line connecting the negative terminal of the smoothing capacitor 11 and the low-side DC line 16.
[0037]
Since the structure and operation of this type of inverter device 3 are already well-known, further description is omitted.
[0038]
(Equipment structure)
Next, the structure of the rotary electric machine equipped with an inverter of this embodiment will be described below with reference to FIG. FIG. 2 is a schematic sectional view in the axial direction of the rotating electric machine.
[0039]
The motor body 2 has a stator core 21, a stator coil 22, a rotor 23 in which permanent magnets are embedded, and a rotating shaft 24. Reference numeral 25 denotes a coil end of the stator coil 22. The stator core 21 is fixed to a frame (not shown), the stator coil 22 is mounted on the stator core 21, the rotor 23 is fitted and fixed to a rotating shaft 24, and the rotating shaft 24 is rotatably supported by the frame. Since this kind of motor main body 2 itself has a well-known configuration, further description is omitted. Of course, it is possible to replace the motor body 2 with another known type of AC motor.
[0040]
FIG. 2 illustrates the semiconductor switching elements 4 and 5, the smoothing capacitor 11, and the current sensor 12 of the inverter device 3 illustrated in FIG. 1, and further illustrates a heat sink (cooling body) 30 as a main component of the inverter device 3. ing.
[0041]
The heat sink (cooling body) 30 has a thick rectangular flat plate shape fixed to a frame (not shown), and has a water cooling passage 31 inside. The water cooling passage 31 is formed at the radial center and the radial outer side of the heat sink 30, but is not formed at the radial inner side of the heat sink 30. The heat sink 30 is disposed on one side in the axial direction of the motor body 2 at a predetermined distance from the coil end 25 so that the pair of main surfaces 32 and 33 are in the radial direction.
[0042]
A smoothing capacitor 11 and a current sensor 12 are mounted and fixed on a main surface 32 of the heat sink 30 on the motor body 2 side. The smoothing condenser 11 is provided adjacent to the water cooling passage 31.
[0043]
The current sensor 12 has a ring-shaped ferrite core 121 with a slit, and a Hall element 122 accommodated in the slit. A stator protruding from the coil end 25 in the center hole of the ferrite core 121 in the axial direction. The lead wire 221 of the coil 22 penetrates. Further, the lead wire 221 penetrates the hole of the heat sink 30 in the thickness direction and protrudes in the axial direction from the non-motor-side main surface 33 of the heat sink 30.
[0044]
On the anti-motor-side main surface 33 of the heat sink 30, the semiconductor switching elements 4 to 9 constituting the three-phase inverter circuit 10 and wiring conductors for connecting them are mounted together with the gate controller 13. However, as described above, FIG. 2 shows only the semiconductor switching elements 4 and 5 and the wiring conductors related thereto in the three-phase inverter circuit 10.
[0045]
The semiconductor switching elements 4 to 9 are mounted on the non-motor side main surface 33 of the heat sink 30 adjacent to the water cooling passage 31. The high-side DC line 15 is fixed on the non-motor-side main surface 33 of the heat sink 30 with a thin electric insulating film interposed therebetween, and the low-side DC line 16 is directly fixed on the non-motor-side main surface 33 of the heat sink 30. However, it may be provided via a thin insulating film. Further, a three-phase AC line of the three-phase inverter circuit 10 is fixed on the non-motor-side main surface 33 of the heat sink 30 with a thin electric insulating film interposed therebetween. Reference numeral 19 denotes a U-phase AC line among the three-phase AC lines. Each of these lines consists of a flat copper wire.
[0046]
The semiconductor switching elements 5, 7, 9 on the lower arm side are fixed on an AC line, and the semiconductor switching elements 4, 6, 8 on the upper arm side are fixed on a DC line 15.
[0047]
The leading ends of the three-phase lead wires 221 of the stator coil 22 are individually connected to these AC lines. In FIG. 2, the U-phase lead wire 221 is connected to the U-phase AC line 19, and the connection portion is covered with a resin 20 by insulation.
[0048]
15 'is a wiring connecting the lower main electrode terminal of the upper arm side semiconductor switching element 4 and the AC line 15, and 19' is a wiring connecting the lower main electrode terminal of the lower arm side semiconductor switching element 5 and the DC line 16. This is the wiring connecting.
[0049]
The DC line 15 is connected to a high-level electrode terminal of the smoothing capacitor 11 through a wiring 17, and the DC line 16 is connected to a low-level electrode terminal of the smoothing capacitor 11 through a wiring 18.
[0050]
The gate controller 13 is mounted on the DC line 16 in an electrically insulated state, receives a detection signal from the Hall element 122 through a wiring 123 electrically insulated from the heat sink 30, and receives a gate signal of each of the semiconductor switching elements 4 to 9 through a wiring (not shown). A control voltage is applied to the electrode terminals.
[0051]
(Example effects)
The inverter-equipped rotary electric machine of this embodiment having such an arrangement of the smoothing capacitor 11 and the semiconductor switching elements 4 to 9 uses a cooling body by using the main surface of the heat sink as the semiconductor switching element cooling surface and the smoothing capacitor cooling surface. In addition to reducing the size of the heat sink, the total axial length of the rotating electric machine can be reduced as compared with the case where the semiconductor switching elements 4 to 9 and the smoothing capacitor 11 are formed in two stories on the same side. The cooling performance of the semiconductor switching elements 4 to 9 can be improved as compared with the case where the smoothing capacitor 11 is disposed on the non-motor-side main surface 33 and the semiconductor switching elements 4 to 9 are disposed on the motor-side main surface 32. A rotary electric machine with an excellent inverter can be realized.
(Example 2)
Another embodiment will be described with reference to FIGS. FIG. 3 is a schematic cross-sectional view in the axial direction of the rotating electric machine, and FIG. 4 is an enlarged cross-sectional view of a main part thereof.
[0052]
The rotary electric machine equipped with an inverter according to this embodiment mainly has the water cooling passage (groove) 31 of the heat sink (cooling body) 30 according to the first embodiment opened to the axial motor side, and the flat bottom surface 110 of the smoothing capacitor 11 is connected to the heat sink 30. This is characterized in that it is closely attached to and fixed to the main surface 301 on the motor side and is closed by the smoothing condenser 11 of the water cooling passage 31.
[0053]
More specifically, the smoothing capacitor 11 is a film capacitor, and houses an electrode assembly 112 including a dielectric film housed in a resin case 111 and a pair of electrodes sandwiching the dielectric film. Therefore, the flat bottom surface 110 of the smoothing capacitor 11 means the flat bottom surface of the resin case 111 of the smoothing capacitor 11, and the water cooling passage 31 is opened in the main surface 301 of the heat sink 30 on the motor side. The water cooling passage 31 formed in a maze shape can be easily manufactured by a usual aluminum die casting method.
[0054]
In this embodiment, the flat bottom surface 110 of the resin case 111 of the smoothing capacitor 11 and the motor-side main surface 301 of the heat sink 30 are joined by using a resin adhesive. A metal may be deposited or fixed on the substrate, and the metal and the heat sink may be joined with solder or the like. Further, the smoothing capacitor 11 and the heat sink 30 may be fastened via an O-ring by a fastening bolt or the like (not shown). The fastening bolts may be used for fixing the heat sink 30 to the motor housing.
(Modification)
In the second embodiment, the main surface 301 of the heat sink 30 on the motor side is a flat surface, but the entire resin case of the smoothing capacitor 11 partially or entirely falls on the main surface 301 of the heat sink 30 on the motor side in the thickness direction. It is also possible to provide a concave portion and bury the smoothing capacitor 11 partially or entirely in this concave portion.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a rotary electric machine equipped with an inverter according to a first embodiment.
FIG. 2 is a schematic axial sectional view of the inverter-mounted rotary electric machine of FIG. 1;
FIG. 3 is a schematic sectional view in the axial direction of a rotary electric machine according to a second embodiment.
FIG. 4 is an enlarged sectional view of a main part of FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Battery 2 Motor main body 3 Inverter device 4-9 Semiconductor switching element 10 Three-phase inverter circuit 11 Smoothing capacitor 30 Heat sink (cooling body)

Claims (8)

A motor body including an AC motor, and an inverter device that is fixed to one axial side of the motor body and controls power transfer between a DC power supply and a stator coil of the motor body,
The inverter device includes:
A predetermined number of semiconductor switching elements that constitute an inverter circuit that is provided between the DC power supply and the stator coil and performs orthogonal transformation;
A smoothing capacitor connected between a pair of DC terminals of the inverter circuit,
A cooling body that cools the semiconductor switching element and the smoothing capacitor in contact with the semiconductor switching element and the smoothing capacitor;
In the rotary electric machine equipped with an inverter,
The smoothing capacitor,
Of a pair of main surfaces of the cooling body extending in the radial direction, the cooling body is fixed to a motor-side main surface facing the motor body,
The semiconductor switching element,
An inverter-mounted rotary electric machine, wherein the rotating body is fixed to a main surface of the pair of main surfaces of the cooling body that is not facing the motor body and is opposite to the motor. The rotary electric machine equipped with an inverter according to claim 1,
The inverter device includes:
A first conductor that is closely attached to the opposite motor-side main surface of the cooling body via an electrical insulator;
An upper arm element of the inverter circuit configured by the semiconductor switching element mounted on the first conductor;
A rotary electric machine equipped with an inverter, comprising: The inverter-mounted rotary electric machine according to claim 2,
The first conductor,
An inverter-mounted rotary electric machine comprising a high-level electrode terminal of the DC power supply. The inverter-mounted rotary electric machine according to claim 2,
The inverter device includes:
A second conductor that is directly in close contact with the non-motor-side main surface of the cooling body,
A lower arm element of the inverter circuit configured by the semiconductor switching element mounted on the second conductor;
A rotary electric machine equipped with an inverter, comprising: The second conductor,
An inverter-mounted rotary electric machine, comprising an AC output line of the inverter circuit connected to a lead wire of the stator coil. The rotary electric machine equipped with an inverter according to claim 1,
The inverter device includes:
An inverter-equipped rotating electric machine, comprising: a control microcomputer that is in contact with the main surface of the cooling body on the side opposite to the motor, and that outputs information on the state of the inverter circuit to the outside. The rotary electric machine equipped with an inverter according to claim 4,
The cooling body has a groove having an opening in the motor-side main surface and forming a cooling fluid flow path,
The rotating electric machine with an inverter mounted therein, wherein the smoothing capacitor is fixed to the main surface of the cooling body on the motor side and closes the opening of the groove. In a circuit device including a heat sink having a pair of main surfaces parallel to each other, a capacitor fixed to one main surface of the heat sink, and a circuit unit fixed to another main surface of the heat sink,
The heat sink has a groove that has an opening in the one main surface of the heat sink and forms a cooling fluid flow path,
The circuit device, wherein the capacitor is fixed to the one main surface of the heat sink to close the opening of the groove.

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