JP2002009477A - Power module refrigerator for controlling electric motors - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a partial temperature deviation in a heat sink having a plurality of mounted power modules for electric motors, thereby efficiently cooling each power module. SOLUTION: A refrigerator of the power module for controlling electric motors comprises a plurality of power modules 1, 2 for controlling a plurality of electric motors and a cooling heat sink 3 to which each power module is attached. The heat sink 3 has fluid passages 30 which total surface area is increased with the increase of the heat per unit area at a position corresponding to each power module. This exchanges heat through a refrigerant on the total surface area of the passages according to the heating rate of each power module, so that a partial temperature deviation in the heat sink is eliminated to ensure optimum cooling for each power module.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power module cooling device for controlling a motor, and more particularly, to a power module cooling technique suitable for a hybrid drive device using both an engine and a motor as a power source.

[0002]

2. Description of the Related Art Devices using a plurality of electric motors (the term "motor" in this specification includes a motor and a generator used as a motor) as a power source, particularly, an engine and an electric motor are used in combination. A hybrid drive device requires a drive circuit (a power module mainly composed of a switch element when the motor is an AC induction type) for controlling a motor and a generator, and generates heat from the motor itself, the motor, the engine, and the like. In order to prevent overheating due to heat and to guarantee the circuit operation, it is essential to provide a cooling device.

[0003] As a cooling technique for a power module for controlling a motor in such a hybrid drive device, a conventional technology is
There is a technique disclosed in JP-A-11-69510. In this prior art, a power module for a generator (the drive circuit 191 in the above-mentioned publication) and a power module for a motor (the same drive circuit 192) are respectively attached to a common heat sink (the same heat sink 256). One flow path for cooling both power modules with water is formed inside the heat sink.

[0004]

Generally, the maximum temperature of the heat sink is set to be lower than the guaranteed temperature of the heating element attached to the heat sink. However, in the above-described conventional cooling technology of a hybrid drive device, in a steady state, that is, in a state where power is consumed for driving the motor by an amount of power generated by the generator driven by the engine, the power module for the generator and the motor for the motor are used. Although the control current value of the power module is the same and the heat generation amount is the same, the maximum current value of the switching operation is mainly between the motor used for generating the driving force and the generator used for power generation. Differently, since the size of the power module varies accordingly, the contact area of the power module with the heat sink also naturally varies, resulting in a difference in heat generation per unit area. With regard to this heat generation per area, the above-mentioned conventional technology does not take special consideration, so that a part of the heat is cooled more than necessary, so that the temperature of the heat sink becomes uneven.

As described above, the power module for a generator is frequently used in a steady state with a small variation in current value, whereas the power module for a motor is used for starting and accelerating a vehicle. When a motor is to output a high torque, it controls a much larger current than in a steady state, even for a relatively short period of time. The difference in how the two power modules are used has also caused the above-mentioned unevenness in the heat sink temperature.

Therefore, the present invention provides a motor control power module cooling device that efficiently cools each power module by eliminating a partial temperature deviation of a heat sink to which a plurality of motor power modules are attached. The purpose is to:

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an electric motor control comprising a plurality of power modules for controlling a plurality of electric motors, respectively, and a cooling heat sink provided with each of the power modules. In the power module cooling device for use, the heat sink has a flow path having a larger flow path total surface area as a heat generation per unit area at a position corresponding to each power module is larger.

[0008] In the above structure, a refrigerant circulation path for circulating a single refrigerant through the flow path of the heat sink is provided, and the plurality of power modules include first and second power modules.
If the first power module generates a larger amount of heat per unit area than the second power module, the total flow channel surface area at the position corresponding to the first power module is It is effective to adopt a configuration that is larger than the total flow path surface area at the position corresponding to the second power module.

In the above structure, the cross-sectional area of the flow path at a position corresponding to the first power module and the cross-sectional area of the flow path at a position corresponding to the second power module are different from each other. It is more effective to adopt a configuration in which the flow rates of the refrigerant are set to be equal.

Next, the present invention provides first and second power modules for controlling the first and second electric motors, respectively.
A cooling heat sink provided with the first and second power modules; and a refrigerant circulation path for circulating a single refrigerant through the flow path of the heat sink, wherein the first power module is a second power module. In the electric power module cooling device for controlling a motor, wherein the heat generation amount per unit area is larger,
And a flow path at a position corresponding to the second power module downstream of the flow path at the position corresponding to the second power module.

[0011] More specifically, the first power module is a generator power module for controlling a generator, and the second power module is a motor power module for controlling a motor.

Further, the present invention provides a generator power module for controlling a generator, a motor power module for controlling a motor, a cooling heat sink provided with the generator power module and the motor power module, and the heat sink. And a refrigerant circulation path for circulating a single refrigerant through the flow path of the motor, wherein the heat sink corresponds to the motor power module downstream of the flow path at a position corresponding to the generator power module. And the total surface area of the flow path at the position corresponding to the power module for the motor is made larger than the total surface area of the flow path at the position corresponding to the power module for the generator.

In the above configuration, the cross-sectional area of the flow path at the position corresponding to the power module for generator and the cross-sectional area of the flow path at the position corresponding to the power module for motor are determined by the flow rate of the refrigerant in each flow path. It is also effective to adopt a configuration that is set to be equal.

Further, in the above configuration, the depth of the flow path at the position corresponding to the power module for the generator may be set to be deeper than the depth of the flow path at the position corresponding to the power module for the motor. It is valid.

In the above configuration, it is also effective that the flow path of the heat sink is formed along the longitudinal direction of the corresponding power module.

[0016]

In the configuration according to the first aspect of the present invention, heat exchange with the refrigerant is performed on the total surface area of the flow passage in accordance with the calorific value of each power module, so that the heat sink temperature is partially reduced. Since it is possible to eliminate such a bias, optimal cooling performance can be ensured for each power module.

Next, according to the second aspect of the present invention, the area of the heat sink in contact with the refrigerant can be increased on the side of the first power module which requires more cooling. Cooling that does not exceed the operation guarantee temperature is possible. In addition, in some places,
The temperature of the heat sink can be made uniform without excessive cooling of the power module side. Moreover, by making the heat sink temperature uniform in this way, it is possible to reduce energy consumption such as electric power of a pump driving motor for circulating the refrigerant, thereby improving the heat exchange efficiency including the entire refrigerant circulation system. be able to.

Further, according to the configuration of the third aspect, the heat transfer of each part can be made uniform, and the temperature of the heat sink can be made more uniform.

Next, in the configuration according to the fourth aspect, the refrigerant after the first power module is cooled first can still be a sufficient refrigerant for the second power module. By adjusting the order, both the first and second power modules can be efficiently cooled. Further, the temperature of the heat sink can be made uniform without excessive cooling of a part, that is, the second power module side. Moreover, by making the heat sink temperature uniform in this way, it is possible to reduce energy consumption such as electric power of a pump driving motor for circulating the refrigerant, thereby improving the heat exchange efficiency including the entire refrigerant circulation system. be able to.

Further, according to the configuration of the fifth aspect, the power module for the motor and the power module for the generator of the hybrid drive device including the motor and the generator can be appropriately cooled in accordance with their heat generation state.

Next, in the configuration according to the sixth aspect, the flow path corresponding to the motor power module is located downstream of the flow path corresponding to the generator power module, and the heat exchange with the power module causes the flow path to become more downstream. In accordance with the rise of the refrigerant temperature, the total surface area of the flow path corresponding to the power module for the motor is made larger than the total surface area of the flow path corresponding to the power module for the generator. It is possible to secure an optimal flow path total surface area in consideration of the rise.

In the structure according to the seventh aspect, in a positional relationship where the flow path corresponding to the motor power module is located downstream of the flow path corresponding to the generator power module, the heat transfer of each part is made uniform. Thus, the temperature of the heat sink can be made more uniform.

Further, in the configuration according to the eighth aspect, the thickness of the heat sink from the contact portion between the motor power module and the heat sink to the flow path is increased, so that the motor power module which is often used transiently is provided. Since a large amount of heat mass can be taken, even if the cooling due to heat release to the refrigerant is transiently insufficient, the temperature rise can be buffered by the accumulation of heat in the heat mass,
It is possible to protect a motor power module that is more likely to generate heat rapidly and for a short time.

Further, in the structure according to the ninth aspect, since the folded portion of the flow path can be reduced with respect to the total length of the flow path at the position corresponding to each heat sink, the flow path resistance in the heat sink can be reduced as a whole. Can be made smaller.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 conceptually shows a power module cooling device for motor control to which the present invention is applied. This device includes first and second power modules 1 and 2 for controlling a generator (not shown) as a first electric motor and a motor (not shown) as a second electric motor, respectively.
And a heat sink 3 for cooling provided with the first and second power modules, and a refrigerant circulation path 4 for circulating a single refrigerant through the flow path of the heat sink 3. In this case, the first power module 1 generates a larger amount of heat per unit area than the second power module 2.

In the cooling device having such a configuration,
According to the present invention, as shown in FIG. 2 showing the bottom shape and FIG. 3 showing the cross-sectional shape, the heat sink 3 has a heat generation per unit area at a position corresponding to each of the power modules 1 and 2 shown by a broken line in FIG. The larger the channel, the larger the total surface area of the channel (the sum of the area of the bottom surface and both side surfaces of the groove constituting the channel when the channel is a groove having a rectangular cross section as shown in the figure).
Has zero. Further, the heat sink 3 is provided downstream of the flow path 31 at a position corresponding to the first power module 1, at a position corresponding to the second power module 2.
2

Returning to FIG. 1, the cooling device in this embodiment is attached to an upper portion of a drive device case 5 in a hybrid drive device, which incorporates a motor, a generator, a differential device, a counter gear mechanism, and the like (not shown). And a water pump 41 for circulating cooling water as a single coolant through the heat sink 3, a radiator 42 as a heat exchanger, and flow paths 40a, 40b, 40c connecting them.
It is composed of It should be noted that auxiliary equipment such as a drive motor of the water pump 41 is not shown.

A discharge side flow path 40a of the water pump 41 as a starting point of the refrigerant circulation path is connected to an inlet port 30a of the heat sink 3, and an outlet port 30b of the heat sink 3 is connected to an inlet 42a side of the radiator 42. The outlet 42 b of the radiator 42 is connected to the suction-side channel 40 c of the water pump 41. Therefore, in this refrigerant circuit, the cooling water as the refrigerant is
After being sent out from the water pump 41, it is heated by absorbing heat from both power modules 1 and 2 in the heat sink 3, sent to the radiator 42, cooled by radiating heat to the air, and returned to the water pump 41. The cycle that ends one cycle is repeated.

As shown in FIG. 2, the flow paths of the heat sink 3 correspond to the first power module 1 and the second power module 2, respectively.
Are formed along the longitudinal direction of the power module 2, and the bottom side is an open groove. Specifically, the flow path 31 corresponding to the first power module 1 attached to the heat sink 3 with the direction transverse to the longitudinal direction as the longitudinal direction.
Extends in a direction transverse to the longitudinal direction of the heat sink 3,
A meandering flow path that is folded in the vicinity of the end, and a flow path 32 corresponding to the second power module 2 attached to the heat sink 3 with the longitudinal direction being the longitudinal direction.
Is a meandering channel that extends in the longitudinal direction of the heat sink 3 and turns near the end. With this configuration, the flow path folded portion 31b,
Since 32b can be reduced, the flow path resistance in the heat sink can be reduced. The above two flow paths basically constitute one flow path connected in an upstream / downstream relationship, but in this embodiment, a sufficient contact area between the refrigerant and the heat sink 3 is secured. For this purpose, intermediate heat transfer walls 31a and 32a acting as heat transfer fins in the flow passage are provided along the groove, one at the deep groove side of the flow passage 31 and nine at the shallow groove side of the flow passage 32. .

Further, as shown in FIG. 3, the depth of the groove of the flow path 31 at the position corresponding to the first power module 1 is the same as the depth of the groove of the flow path 32 at the position corresponding to the second power module 2. It is set deeper than the depth. With this configuration, the motor power module 2 and the heat sink 3
By providing the heat sink from the contact portion to the flow path 32 with a thickness, a large amount of heat mass can be obtained on the side of the motor power module 2 that is often used transiently, so that cooling by heat radiation to the cooling water can be performed. Even in the case of transient shortage, since the temperature rise can be buffered by the accumulation of heat in the heat mass, it is possible to protect the motor power module 2 which is more likely to generate heat rapidly and in a short time.

As shown in FIGS. 2 and 3, the cross-sectional area of the flow path at the position corresponding to the first power module 1 of the heat sink 3 and the cross-sectional area of the flow path at the position corresponding to the second power module 2 Are set so that the flow rates of the refrigerant in the respective flow paths become equal. Therefore, from the relationship with the heat mass, the flow path in contact with the first power module 1 is configured by a groove having a small width and a large depth, and the flow path in contact with the second power module 2 is:
The groove is wide and shallow. The connecting portion 31c of the two flow paths 31 and 32 gradually reduces the depth from the flow path 31 side to the flow path 32 side so as to smoothly connect the two flow paths and not to cause a throttle effect. The connection groove is widened.

The reason why the present embodiment employs such a structure that the flow velocity of the refrigerant is equal will be described with reference to the characteristic diagram of FIG. This figure shows the thermal resistance between water as the refrigerant and aluminum as the heat sink material with high thermal conductivity as a function of the flow rate of the refrigerant. Here, the thermal resistance indicates how heat is transmitted, and the larger the value, the more difficult it is for heat to be transmitted, indicating that the cooling performance is inferior. In the figure, the reason why the characteristic greatly changes near the flow velocity A is because the flow of the refrigerant changes from laminar flow to turbulent flow in this vicinity. What can be said from this characteristic is that the rate of reduction in thermal resistance decreases as the flow velocity is increased. In other words, the relationship between the flow velocity and the heat transfer efficiency includes the energy required to drive the water pump 41 to increase the flow velocity, the energy loss due to the increase in the flow path resistance accompanying the increase in the flow velocity, and the cooling due to the increase in the flow velocity. This means that there is a specific optimum value that takes into account the balance with improved effects. Therefore, in order to increase the cooling efficiency of the heat sink 3, it is effective to set the flow velocity to a certain optimum value. By the way, from this knowledge, in the present embodiment, the flow velocity is set to a constant value for each part.
And a flow path cross-sectional area where the flow velocity is maintained is adopted.

The positions of the inlet 30a and the outlet 30b with respect to the heat sink, and the shape of the flow path for introduction and discharge from the heat sink to the flow path 31 and the flow path 32 are restricted by the mounting positions of the power modules 1 and 2. It is not something to be done. Although not shown, the bottom side of the heat sink 3 is
The drive device case 5 is covered by being brought into contact with an appropriate member such as an outer wall or a cover on the upper portion of the drive device case 5 and attached in a leak-proof state.

In the cooling device having such a configuration, the cooling water sent from the inlet 30a to the heat sink 3 is divided into two streams by the intermediate heat transfer wall 31a. The groove wall and the intermediate heat transfer wall 31a while flowing at the predetermined flow rate in the longitudinal direction
Of the flow path 31 and the flow path 32 through the 180-degree folded portions 31b at five points on the way.
Reaches 0c. From this position, the cooling water changes direction,
The intermediate heat transfer wall 32a divides the flow into 10 streams, and the flow path 32
The groove wall and the intermediate heat transfer wall 32a also flow at a predetermined flow rate in the longitudinal direction of the motor power module 2 along the groove.
And reaches the outlet 30b via two 180-degree folded portions 32b on the way. In addition, entrance 3
The flow of the cooling water outside the heat sink 3 following 0a and the outlet 30b is as described above.

Although the present invention has been described in detail based on one embodiment in which the present invention is applied to a power module of a hybrid drive device, the present invention is not limited to this, and various applications using power modules with similar thermal conditions are applicable. It can be applied to the devices. Also, the refrigerant used for cooling is not limited to water, and various refrigerants can be used.

[Brief description of the drawings]

FIG. 1 is an overall conceptual diagram of a motor control power module cooling device according to an embodiment of the present invention.

FIG. 2 is a bottom view of a heat sink of the cooling device.

FIG. 3 is a side view showing a heat sink of the cooling device in a cross section only of a flow path forming portion.

FIG. 4 is a characteristic diagram showing a relationship between a flow velocity of a refrigerant and a thermal resistance.

[Explanation of symbols]

Reference Signs List 1 power module for generator (first power module) 2 power module for motor (second power module) 3 heat sink 31, 32 flow path 4 refrigerant circulation path

Claims (9)

[Claims] 1. A motor control power module cooling device comprising: a plurality of power modules for controlling a plurality of electric motors; and a cooling heat sink provided with each of the power modules, wherein the heat sink corresponds to each of the power modules. A power module cooling device for controlling an electric motor, characterized by having a flow path having a larger flow path total surface area as the amount of heat generated per unit area at a position where the heat is generated is larger. 2. A refrigerant circuit for circulating a single refrigerant through a flow path of the heat sink, wherein the plurality of power modules comprises first and second two power modules, and wherein the first power module is , The calorific value per unit area is larger than that of the second power module, and the total flow surface area at the position corresponding to the first power module is larger than the total flow surface area at the position corresponding to the second power module. The power module cooling device for controlling an electric motor according to claim 1, which is enlarged. 3. The cross-sectional area of the flow path at the position corresponding to the first power module and the cross-sectional area of the flow path at the position corresponding to the second power module are equal in the flow velocity of the refrigerant in each flow path. Was set in a relationship
The power module cooling device for controlling a motor according to claim 2. 4. A first and second power module for controlling the first and second electric motors respectively, a cooling heat sink provided with the first and second power modules, and a flow path of the heat sink. A refrigerant circuit for circulating a single refrigerant, wherein the first power module comprises:
In the electric power module cooling device for motor control, wherein the heat generation amount per unit area is larger than that of the second power module, the heat sink is provided with a second power downstream of a flow path at a position corresponding to the first power module. A power module cooling device for controlling a motor, comprising a flow path at a position corresponding to a module. 5. The power module according to claim 2, wherein the first power module is a power module for a generator that controls a generator, and the second power module is a power module for a motor that controls a motor. Power module cooling device for motor control. 6. A power module for a generator for controlling a generator, a power module for a motor for controlling a motor, a heat sink for cooling provided with the power module for the generator and the power module for the motor, and a flow path of the heat sink. And a refrigerant circulation path for circulating a single refrigerant, wherein the heat sink has a flow path at a position corresponding to the motor power module downstream of a flow path at a position corresponding to the generator power module. A power module cooling device for controlling a motor, wherein the cooling device has a passage and a total surface area of the passage at a position corresponding to the power module for the motor is made larger than a total surface area of the passage at a position corresponding to the power module for the generator. . 7. A relationship in which the cross-sectional area of the flow path at a position corresponding to the power module for generator and the cross-sectional area of the flow path at a position corresponding to the power module for motor are such that the flow rates of the refrigerant in the respective flow paths are equal. The power module cooling device for controlling a motor according to claim 6, wherein the cooling device is set to: 8. The flow channel according to claim 5, wherein the depth of the flow channel at a position corresponding to the generator power module is set to be deeper than the depth of the flow channel at a position corresponding to the motor power module. Power module cooling device for motor control. 9. The electric motor control power module cooling device according to claim 2, wherein the flow path of the heat sink is formed along a longitudinal direction of the corresponding power module.