JP2017184368A - Inverter device - Google Patents

Abstract

An object of the present invention is to level the life of each of a plurality of switching elements arranged in an inverter device.
An inverter device 1 includes a plurality of switching elements 44a to 44f arranged in a predetermined arrangement, and arranged in a predetermined arrangement corresponding to each switching element 44a to 44f. A heat dissipating part 13c that dissipates heat, a cooling device 20 that cools the heat dissipating part 13c, and a control device 30 are provided. The cooling device 20 extends along the arrangement of the heat radiating portions 13c, and is a flow passage through which a refrigerant that exchanges heat with the heat radiating portions 13c circulates. A first flow passage 21 that can be switched to the second direction D2 that flows to the other side, and a switching valve 24 that switches between the first direction D1 and the second direction D2 are provided. The control device 30 includes a switching control unit (step S116) that controls switching of the switching valve 24 from each element temperature of the plurality of switching elements 44a to 44f.
[Selection] Figure 1

Description

  The present invention relates to an inverter device.

  As one type of the inverter device, one shown in Patent Document 1 is known. As shown in FIG. 1 of Patent Document 1, the inverter device of Patent Document 1 cools the power control unit 30 and the motor 32 by circulating a cooling medium (refrigerant) in one direction when the motor 32 is driven. . On the other hand, when the battery 28 is charged (when the motor 32 is not driven), the refrigerant circulates in the direction opposite to the one direction, whereby the motor 32 is bypassed and only the power control unit 30 is cooled. Thereby, overheating of the power control unit 30 during charging from an external power source can be suppressed with a relatively simple configuration.

JP 2012-228999 A

In the power control unit 30, switching elements such as IGBTs are arranged in a predetermined arrangement. When the cooling medium circulates in one direction when the motor is driven as in the inverter device of Patent Document 1 described above, the switching element disposed on the upstream side in the refrigerant flow direction is changed to the switching element disposed on the downstream side. Cooling is more efficient. Therefore, the switching element disposed on the downstream side may have a greater degree of thermal stress and thus the degree of deterioration than the switching element disposed on the upstream side. In this case, since the life of the switching element arranged on the downstream side is exhausted earlier than the life of the switching element arranged on the upstream side, the life of the inverter device becomes relatively short.
The present invention has been made to solve the above-described problems, and an object of the present invention is to level the lifetime of each of a plurality of switching elements arranged in an inverter device.

  In order to solve the above problems, an inverter device according to claim 1 is provided with a plurality of switching elements arranged in a predetermined arrangement, and arranged in a predetermined arrangement corresponding to each switching element. A plurality of heat radiation parts that respectively radiate the elements, a cooling device that cools the heat radiation parts, a temperature detection device that detects each element temperature of the plurality of switching elements, and a control device that controls at least the cooling device. The cooling device is a flow passage that extends along the arrangement of the heat radiating portions and through which the refrigerant that exchanges heat with the heat radiating portions flows, and in which the refrigerant flows in one of the flow passages A first flow path that can be switched to a second direction that flows to the other of the flow paths, and a switching valve that is provided in the first flow path and performs switching between the first direction and the second direction. Temperature detection device From each element temperature detected by, it includes a switching control unit for controlling the switching of the switching valve, the.

  According to this, among the plurality of switching elements arranged in a predetermined arrangement, the upstream switching in the first direction and the second direction in which the refrigerant flows through the first flow path extending along the arrangement of the heat radiating portions. The element is cooled more efficiently than the downstream switching element. Further, the control device controls switching of the switching valve from each element temperature detected by the temperature detection device. Therefore, it is possible to suppress a difference in thermal stress between each of the plurality of switching elements, and hence a difference in the degree of deterioration. Therefore, the lifetimes of the plurality of switching elements arranged in the inverter device can be leveled.

It is a schematic diagram showing a first embodiment of an inverter device according to the present invention. FIG. 2 is a cross-sectional view of the power module and the first flow path along the line II-II shown in FIG. 1. It is a figure which shows the inverter circuit of the power module shown in FIG. FIG. 2 is a time chart when on / off control is executed by the control device shown in FIG. 1, in which an upper stage indicates a control signal for on / off control, and a lower stage indicates an element temperature of the first switching element. It is a flowchart of the switching control which the control apparatus shown in FIG. 1 performs. It is a figure which shows the 2nd correlation and the 3rd correlation memorize | stored in the memory | storage part of the control apparatus shown in FIG. It is a flowchart of the switching control which the control apparatus which concerns on 2nd embodiment of this invention performs. It is a figure which shows the arrangement | sequence of the several switching element which concerns on the modification of each embodiment of this invention. It is a figure which shows the 1st flow path which concerns on the modification of each embodiment of this invention.

<First embodiment>
Hereinafter, a first embodiment of an inverter device according to the present invention will be described. The inverter device 1 of the first embodiment supplies power to a motor (not shown) that is a prime mover of a hybrid vehicle. The motor is a three-phase brushless motor. As shown in FIG. 1, the inverter device 1 includes a power module 10, a cooling device 20, and a control device 30.

  As shown in FIG. 2, the power module 10 includes a casing 11, a substrate 12, and a heat radiating member 13. The casing 11 is formed in a box shape whose bottom surface is opened toward the lower side of FIG. A substrate 12 is accommodated in the casing 11. A heat radiating member 13 is disposed at the bottom of the casing 11. The board | substrate 12 is formed in plate shape with insulating materials, such as a ceramic. An inverter circuit 40 is configured on the surface 12a of the substrate 12 (the upper surface in FIG. 2).

  The inverter circuit 40 converts DC power from a battery (not shown) into three-phase AC and outputs it to the motor. As shown in FIG. 3, in the inverter circuit 40, a U-phase arm 41, a V-phase arm 42, and a W-phase arm 43 are provided in parallel between a positive electrode bus PL and a negative electrode bus NL connected to a battery. The inverter circuit 40 includes a plurality (six in the first embodiment) of switching elements 44a to 44f and a plurality of freewheeling diodes 45a to 45f connected in reverse parallel to each of the plurality of switching elements 44a to 44f. Yes.

  The first and second switching elements 44 a and 44 b are connected in series to the U-phase arm 41. The third and fourth switching elements 44 c and 44 d are connected in series to the V-phase arm 42. The fifth and sixth switching elements 44 e and 44 f are connected in series to the W-phase arm 43. The switching elements 44a to 44f are IGBTs (Insulated Gate Bipolar Transistors).

  The plurality of switching elements 44a to 44f are arranged in a predetermined arrangement as shown in FIGS. The predetermined array is an array of two rows parallel to the left-right direction of FIGS.

  The first switching element 44a includes a first temperature detecting diode 44a1 (corresponding to the temperature detecting device of the present invention). Further, the inverter circuit 40 is provided with a constant current circuit (not shown) in which the current value flowing through the first temperature detection diode 44a1 is a predetermined current value.

  The forward voltage value of the first temperature detection diode 44a1 and the temperature of the first switching element 44a are such that the forward voltage value of the first temperature detection diode 44a1 increases as the temperature of the first switching element 44a increases. The first correlation is lowered. The first correlation is derived by being measured in advance through experiments or the like. The first correlation is stored in the control device 30. The forward voltage value of the first temperature detection diode 44 a 1 is input to the control device 30.

  The switching elements 44b to 44f also have temperature detection diodes 44b1 to 44f1 that are the same as those of the first switching element 44a. In addition, a constant current circuit (not shown) is provided in the inverter circuit 40 in which the current value flowing through the temperature detection diodes 44b1 to 44f1 is a predetermined current value.

  The intermediate point of each phase arm is connected to the power line of each phase of the motor. Specifically, an intermediate point 41a between the first and second switching elements 44a and 44b of the U-phase arm 41 is connected to the U-phase power line. An intermediate point 42a between the third and fourth switching elements 44c and 44d of the V-phase arm 42 is connected to the V-phase power line. An intermediate point 43a between the fifth and sixth switching elements 44e and 44f of the W-phase arm 43 is connected to the W-phase power line.

  Next, the operation of the inverter circuit 40 will be described. A direct current from the battery is supplied to each phase arm 41, 42, 43. In addition, the switching elements 44 a to 44 f are on / off controlled by a PWM (pulse width modulation) control signal output from the control device 30. As a result, the inverter circuit 40 converts the direct current into three-phase alternating current and outputs it to the motor.

  Next, the rising temperature ΔTh of each of the switching elements 44a to 44f in the operation of the inverter circuit 40 will be described with reference to FIG. Since the temperature element degree of each switching element 44a-44f rises similarly, in order to demonstrate easily, only raise temperature (DELTA) Th of the 1st switching element 44a is demonstrated. The on / off control of each switching element 44a to 44f has an energization mode and a non-energization mode. The energization mode is a mode in which the switching elements 44 a to 44 f are intermittently turned on by the PWM control signal output by the control device 30. The non-energization mode is a mode in which the switching elements 44 a to 44 f are continuously turned off when the PWM control signal is not output from the control device 30.

  When the on / off control is in the non-energization mode, since the first switching element 44a is off, no current flows through the first switching element 44a. At this time, since no heat is generated in the first switching element 44a, the temperature of the first switching element 44a does not rise. Therefore, in this case, the element temperature of the first switching element 44a is approximately the same as the refrigerant temperature Thc described later.

  On the other hand, when the on / off control is in the energization mode, a current flows through the first switching element 44a when the first switching element 44a is turned on. On the other hand, when the first switching element 44a is turned off, no current flows through the first switching element 44a. When a current flows through the first switching element 44a, heat is generated in the first switching element 44a, so that the element temperature of the first switching element 44a rises. As the time during which the first switching element 44a is turned on becomes longer, that is, as the duty ratio of the PWM control signal becomes larger, the element temperature of the first switching element 44a and thus the rising temperature ΔTh becomes larger.

  Specifically, when the first time Tm1, the second time Tm2, and the third time Tm3 in which the on / off control is in the energization mode are compared, the duty ratio is in the order of the first time Tm1, the second time Tm2, and the third time Tm3. Since the temperature increases, the rising temperature ΔTh of the first switching element 44a increases in this order.

  The heat radiating member 13 radiates heat from the plurality of switching elements 44a to 44f. The heat radiating member 13 is provided in a rectangular parallelepiped shape with a metal material such as copper. As shown in FIG. 2, the heat dissipation member 13 has a first surface 13a (upper surface in FIG. 2) and a second surface 13b (lower surface in FIG. 2) opposite to the first surface 13a. ing. The heat radiating member 13 is provided in contact with the back surface 12 b (the lower surface in FIG. 2) whose first surface 13 a is opposite to the front surface 12 a of the substrate 12. The first surface 13 a of the heat radiating member 13 is in contact with the entire back surface 12 b of the substrate 12.

  Moreover, the heat radiating member 13 has the heat radiating part 13c. The heat radiating part 13c is a part that radiates heat of each switching element in the heat radiating member 13. The heat radiating portion 13c thermally connects the first surface 13a and the second surface 13b. A plurality of heat dissipating parts 13c are arranged in a predetermined arrangement corresponding to the switching elements 44a to 44f. Specifically, the heat radiating portion 13c is disposed on the first surface 13a so as to face the switching elements 44a to 44f. That is, the arrangement of the heat dissipating portions 13c is an array of two rows parallel to the left and right directions of FIGS. The heat radiating part 13c transmits the heat of the switching elements 44a to 44f from the first surface 13a to the lower side (lower side in FIG. 2) via the substrate 12, and releases it from the second surface 13b.

  The cooling device 20 cools the heat radiating part 13c. As shown in FIG. 1, the cooling device 20 includes a first flow passage 21, a second flow passage 22, a pump 23, a switching valve 24, a strainer 25, a radiator 26, and a reservoir 27.

  The first flow passage 21 is a flow passage (tube) through which a refrigerant that exchanges heat with the heat radiating portion 13c flows. The refrigerant is, for example, an antifreeze liquid. In the first flow path 21, the power module 10 is liquid-tightly arranged so that the refrigerant flows in contact with the entire second surface 13 b of the heat radiating member 13.

  Moreover, the 1st flow path 21 is extended along the predetermined arrangement | sequence of the thermal radiation part 13c. In the first embodiment, the first flow passage 21 extends in the left-right direction in FIGS. 1 and 2 along a predetermined arrangement of the heat dissipating portions 13c. When the refrigerant flows to one of the first flow passages 21 (from the one end 21a side to the other end 21b side of the first flow passage 21), the refrigerant flows through the heat radiating member 13 (second surface 13b) in the first direction D1 (in FIGS. 1 and 2). Flowing from the left to the right).

  Further, when the refrigerant flows in the other direction of the first flow passage 21 (from the other end 21b side to the one end 21a side of the first flow passage 21) by switching the direction in which the refrigerant flows by a switching valve 24 described later, the refrigerant radiates heat. The member 13 flows in the second direction D2 (the direction from the right side to the left side in FIGS. 1 and 2). Thus, the first flow path 21 is a flow path that extends along the arrangement of the heat radiating portions 13c and through which the refrigerant that exchanges heat with the heat radiating portions 13c circulates, and in which the refrigerant flows in one of the flow paths. It is possible to switch between D1 and the second direction D2 flowing in the other of the flow paths.

The second flow passage 22 is a flow passage (tube) through which the refrigerant flows from the one end 22a side toward the other end 22b side.
The pump 23 is provided in the second flow passage 22 and circulates the refrigerant. Specifically, the pump 23 delivers the refrigerant from the one end 22a side of the second flow passage 22 toward the other end 22b side. The pump 23 is driven by a control signal from the control device 30.

  The switching valve 24 is provided in the first flow passage 21 and the second flow passage 22 and switches between the first direction D1 and the second direction D2. The switching valve 24 is a four-way valve. The switching valve 24 includes a casing (not shown) and a valve body (not shown) that switches the flow path by rotating with respect to the casing.

  The casing includes four ports 24a to 24d. One end 21a of the first flow passage 21 is connected to the first port 24a. The other end 21b of the first flow passage 21 is connected to the second port 24b. The other end 22b of the second flow passage 22 is connected to the third port 24c. One end 22a of the second flow passage 22 is connected to the fourth port 24d.

  The valve body includes a first switching channel 24e and a second switching channel 24f. The valve body has a first position and a second position. In the first position, the first switching flow path 24e connects the third port 24c and the first port 24a, and the second switching flow path 24f connects the second port 24b and the fourth port 24d. Is the position. In the second position, the first switching flow path 24e connects the first port 24a and the fourth port 24d, and the second switching flow path 24f connects the third port 24c and the second port 24b. Is the position. In FIG. 1, the first and second switching channels 24e and 24f when the valve body is located at the first position are indicated by solid lines. Moreover, the 1st, 2nd switching flow paths 24e and 24f when a valve body is located in a 2nd position are shown with the broken line.

  The strainer 25 removes foreign matters in the refrigerant. The strainer 25 is formed in a net shape and is detachably provided on the fourth port 24d. The foreign matter is, for example, chips generated when the heat radiating member 13 is cut.

The radiator 26 is provided in the second flow passage 22 between the strainer 25 and the pump 23, and cools the refrigerant. The radiator 26 releases the heat of the refrigerant to the outside air.
The reservoir 27 is provided in the second flow passage 22 between the radiator 26 and the pump 23 and stores the refrigerant.

Next, the operation of the cooling device 20 will be described.
By driving the pump 23, the refrigerant is sent out from the one end 22 a side of the second flow passage 22 toward the other end 22 b side. Thereby, when the valve body is located at the first position, the refrigerant flows from the other end 22b side of the second flow passage 22 into the first switching flow path 24e of the switching valve 24 via the third port 24c, It flows out to the one end 21a side of the first flow passage 21 through one port 24a. Subsequently, the refrigerant flows in the first direction D1 through the first flow path 21 from the one end 21a side to the other end 21b side, and performs heat exchange with the heat radiating portion 13c.

  Further, the refrigerant flows into the second switching flow path 24f of the switching valve 24 from the other end 21b side of the first flow path 21 through the second port 24b, and from the second switching flow path 24f to the fourth port 24d. And flows out to the one end 22 a side of the second flow passage 22. At this time, foreign substances are removed from the refrigerant by the strainer 25.

  The refrigerant flows through the second flow passage 22 from the one end 22a side toward the other end 22b side, and the heat of the refrigerant is released to the outside air by the radiator 26. Subsequently, the refrigerant is temporarily stored in the reservoir 27 and sucked into the pump 23.

  Thus, when the valve body is located at the first position, the refrigerant circulates through the first and second flow passages 21 and 22 so that the refrigerant flows through the heat radiating member 13 in the first direction D1, and radiates heat through the refrigerant. The heat of the member 13 is released to the outside air by the radiator 26.

  On the other hand, when the valve body is switched from the first position to the second position by switching control described later, the refrigerant flows from the other end 22b side of the second flow passage 22 through the third port 24c. It flows into the two switching flow paths 24f and flows out to the other end 21b side of the first flow passage 21 through the second port 24b. Continuously, the refrigerant flows in the second direction D2 from the first flow path 21 toward the one end 21a side from the other end 21b side, and flows into the first switching flow path 24e of the switching valve 24 through the first port 24a. .

  Further, the refrigerant flows out from the first switching flow path 24e to the one end 22a side of the second flow passage 22 through the fourth port 24d. At this time, foreign substances are removed from the refrigerant by the strainer 25. Further, when the refrigerant flows through the first flow passage 21, heat is exchanged with the heat radiating portion 13 c, and when the refrigerant flows through the second flow passage 22, the heat of the refrigerant is released by the radiator 26.

  Thus, when the valve body is located at the second position, the refrigerant circulates through the first and second flow passages 21 and 22 so as to circulate through the heat dissipation member 13 in the second direction D2, and through the refrigerant. The heat of the heat radiating member 13 is released to the outside air by the radiator 26.

  The control device 30 controls at least the cooling device 20. The control device 30 includes a CPU unit (not shown) that executes arithmetic processing and a storage unit (not shown) such as a ROM. The control device 30 controls driving of the motor by executing on / off control for outputting the above-described PWM control signal to each of the switching elements 44a to 44f.

  Next, switching control for controlling switching of the switching valve 24 executed by the control device 30 will be described with reference to the flowchart shown in FIG. The switching control is executed when controlling the driving of the motor. The case where the position of the valve body is the first position, that is, the case where the refrigerant circulates through the first and second flow passages 21 and 22 so as to circulate in the first direction D1 will be described.

  In step S102, control device 30 determines whether the energization mode has been started. When the on / off control is in the non-energization mode, the control device 30 determines “NO” in step S102, and repeatedly executes step S102. On the other hand, when the energization mode is started by outputting the PWM control signal, the control device 30 determines “YES” in step S102 and advances the program to step S104.

  In step S104, control device 30 acquires element temperatures of switching elements 44a to 44f. Specifically, the control device 30 acquires the element temperature of each of the switching elements 44a to 44f from the forward voltage value of each of the temperature detection diodes 44a1 to 44f1 based on the first correlation. The acquired element temperature is stored in the storage unit.

  Subsequently, in step S106, control device 30 determines whether or not the energization mode has ended. When the PWM control signal is output, since the energization mode is continued, the control device 30 determines “NO” in step S106, and repeatedly executes steps S104 and S106. On the other hand, when the output of the PWM control signal is stopped, since the energization mode has ended, the control device 30 determines “YES” in step S106 and advances the program to step S108.

  In step S108, control device 30 derives rising temperature ΔTh of each switching element 44a to 44f (rising temperature deriving unit). Specifically, the control device 30 derives the difference between the minimum value and the maximum value of the element temperatures of the switching elements 44a to 44f in the energization mode stored in the storage unit as the rising temperature ΔTh of each switching element. To do.

  Then, in step S110, control device 30 derives the degree of deterioration of each switching element 44a to 44f (hereinafter referred to as element deterioration degree) (deterioration degree derivation unit). Hereinafter, the degree of element deterioration will be described. The element deterioration degree is a degree of deterioration of the switching elements 44a to 44f when the temperature of the switching elements 44a to 44f is increased by the increase temperature ΔTh. The element deterioration degree has a relationship that is a reciprocal number as will be described later with the number of times of life of the switching elements 44a to 44f (hereinafter referred to as the number of times of element life).

  The number of element lifetimes is the number of times that the switching elements 44a to 44f fail when the thermal stress due to the temperature rise and fall of the switching elements 44a to 44f is repeatedly performed at the same rise temperature ΔTh. The failure of the switching elements 44a to 44f is mainly due to poor contact at the junction (not shown) between the switching elements 44a to 44f and the substrate 12. This poor contact at the joint is caused by fatigue deterioration due to repeated expansion and contraction of the joint. The expansion and contraction of the joint portion is caused by a difference in thermal expansion between the switching elements 44a to 44f and the substrate 12 when the element temperature repeatedly increases and decreases.

  Further, as the rising temperature ΔTh increases, the expansion and contraction of the joint portion increases, so that the degree of prevention deterioration increases and the number of element lifetimes decreases. That is, the rising temperature ΔTh and the number of element lifetimes have a second correlation in which the number of element lifetimes decreases as the rising temperature ΔTh increases, as shown by the broken line in FIG. Further, as shown by the solid line in FIG. 6, the temperature rise ΔTh and the element deterioration degree are the third correlation in which the element deterioration degree increases as the rise temperature ΔTh increases (corresponding to the correlation of the present invention). Have Thus, the element deterioration degree is in a relationship that is approximately the inverse of the element lifetime.

  Further, the second correlation is derived by being measured in advance through experiments or the like. Therefore, the third correlation between the rising temperature ΔTh and the element deterioration degree can also be derived in advance. The third correlation is stored in the storage unit.

  As described above, the control device 30 changes the element deterioration degree from the rising temperature ΔTh derived by the rising temperature deriving unit (step S108) based on the third correlation between the rising temperature ΔTh and the element deterioration degree to a plurality of switching points. Derived for each of the elements 44a to 44f.

Returning to FIG. 5, the description of the flowchart will be continued.
In step S112, control device 30 derives the integrated deterioration degree of each switching element 44a to 44f. The integrated deterioration degree is a value obtained by integrating the element deterioration degrees derived by the deterioration degree deriving unit (step S110) from the start of use of the vehicle to the present time for each of the plurality of switching elements 44a to 44f. The integrated deterioration degree of each switching element 44a to 44f is stored in the storage unit.

  Then, in step S114, control device 30 determines whether or not the difference between the maximum value and the minimum value of the integrated deterioration levels of switching elements 44a to 44f is greater than or equal to the deterioration determination value. When the difference between the integrated deterioration levels of the switching elements 44a to 44f is relatively small, the difference between the maximum value and the minimum value of the integrated deterioration levels of the switching elements 44a to 44f is smaller than the deterioration determination value. Determines “NO” in step S114, and returns the program to step S102. As described above, when the difference between the maximum value and the minimum value of the integrated deterioration levels of the switching elements 44a to 44f is smaller than the deterioration level determination value, the control device 30 repeatedly executes steps S102 to S114.

  On the other hand, as a result of a relatively large difference in the cumulative deterioration degree of the switching elements 44a to 44f, the difference between the maximum value and the minimum value of the cumulative deterioration degree of the switching elements 44a to 44f is equal to or greater than the deterioration degree determination value. If so, the control device 30 determines “YES” in step S114, and advances the program to step S116. The deterioration degree determination value is set by experimental measurement in advance so that the lifetime of each switching element 44a to 44f is leveled.

  In step S116, the control device 30 switches the refrigerant flow direction (switch control unit). Specifically, the control device 30 switches the position of the valve body. When the position of the valve body is the first position, the valve body is switched to the second position. Thereby, when the position of a valve body turns into a 2nd position, it circulates through the 1st, 2nd flow paths 21 and 22 so that a refrigerant | coolant may distribute | circulate the thermal radiation member 13 to the 2nd direction D2. Then, the control device 30 returns the program to step S102.

  Next, the operation of the inverter device 1 when the control device 30 executes the switching control will be described. When the on / off control is executed to control the drive of the motor, when the valve body is in the first position, that is, the first and second refrigerants 13 circulate in the first direction D1. A description will be given from when the second flow passages 21 and 22 are circulated.

  When each of the switching elements 44a to 44f is on / off controlled, when the on / off control is in the energization mode, heat is generated in each of the switching elements 44a to 44f, so that the element temperature rises as shown in FIG. . The heat generated in each of the switching elements 44a to 44f is transmitted to the heat radiating portion 13c and released to the refrigerant, whereby the switching elements 44a to 44f are cooled. Further, when the refrigerant flows through the heat dissipation member 13 in the first direction D1, the first and second switching elements 44a and 44b on the upstream side in the first direction D1 are the fifth and the fifth on the downstream side in the first direction D1. Cooling is performed more efficiently than the sixth switching elements 44e and 44f.

  The first and second switching elements 44a and 44b are more efficiently cooled than the fifth and sixth switching elements 44e and 44f, so that the first and second switching elements 44a and 44b have a fifth element degradation degree. This is suppressed compared to the element deterioration degree of the sixth switching elements 44e and 44f. As a result, when the difference between the maximum value and the minimum value of the integrated deterioration levels of the switching elements 44a to 44f is equal to or greater than the deterioration level determination value (step S114), the control device 30 sets the position of the valve body to the first position. To the second position (step S116).

  When the position of the valve body is the second position, since the refrigerant flows through the heat dissipation member 13 in the second direction D2, the fifth and sixth switching elements 44e and 44f on the upstream side in the second direction D2 are in the second direction. Cooling is performed more efficiently than the first and second switching elements 44a and 44b on the downstream side of D2. Thereby, the element deterioration degree of the fifth and sixth switching elements 44e and 44f is suppressed as compared with the element deterioration degree of the first and second switching elements 44a and 44b. Therefore, since the difference between the integrated deterioration degree of the first and second switching elements 44a and 44b and the integrated deterioration degree of the fifth and sixth switching elements 44e and 44f becomes small, the integrated deterioration degree of each of the switching elements 44a to 44f. The difference is suppressed.

  According to the first embodiment, the inverter device 1 is arranged in a predetermined arrangement corresponding to the plurality of switching elements 44a to 44f arranged in a predetermined arrangement and the switching elements 44a to 44f. , A plurality of heat dissipating parts 13c for radiating heat from each switching element 44a to 44f, a cooling device 20 for cooling the heat dissipating part 13c, and a temperature detecting diode 44a1 for detecting the element temperature of each of the plurality of switching elements 44a to 44f. -44f1 and the control apparatus 30 which controls the cooling device 20 at least. The cooling device 20 extends along the arrangement of the heat radiating portions 13c, and is a flow passage through which a refrigerant that exchanges heat with the heat radiating portions 13c flows, and the first direction D1 in which the refrigerant flows to one of the flow passages and the flow passage A first flow path 21 that can be switched to the second direction D2 that flows to the other side, and a switching valve 24 that is provided in the first flow path 21 and switches between the first direction D1 and the second direction D2 are provided. . The control device 30 includes a switching control unit (step S116) that controls switching of the switching valve 24 from each element temperature detected by the temperature detection diodes 44a1 to 44f1.

  According to this, among the plurality of switching elements 44a to 44f arranged in a predetermined arrangement, the first direction D1 and the second direction in which the refrigerant flows in the first flow path 21 extending along the arrangement of the heat radiating portion 13c. The switching element on the upstream side in the direction D2 is cooled more efficiently than the switching element on the downstream side. The control device 30 controls switching of the switching valve 24 from each element temperature detected by the temperature detection diodes 44a1 to 44f1. Therefore, the difference in thermal stress between each of the plurality of switching elements 44a to 44f, and hence the difference in the deterioration level (integrated deterioration level) can be suppressed. Therefore, the life of each of the plurality of switching elements 44a to 44f arranged in the inverter device 1 can be leveled.

  Moreover, since the flow direction of the refrigerant is switched, the foreign matter adhering to the heat radiating member 13 can be easily dropped compared to the case where the flow direction of the refrigerant is not switched. Therefore, it is possible to suppress a decrease in cooling capacity due to foreign matters adhering to the heat radiating member 13.

  Further, the control device 30 derives an elevated temperature deriving unit for deriving the elevated temperature ΔTh of the switching element in the energization mode among the plurality of switching elements 44a to 44f from the element temperatures detected by the temperature detection diodes 44a1 to 44f1. (Step S108) and the third degree correlation between the rising temperature ΔTh and the element deterioration degree, the element deterioration degree is derived for each of the plurality of switching elements 44a to 44f from the rising temperature ΔTh derived by the rising temperature deriving unit. And a deterioration degree deriving unit (step S110). The switching control unit controls switching of the switching valve 24 from each element deterioration level derived by the deterioration level deriving unit.

  According to this, since the control device 30 controls the switching of the switching valve 24 from each element deterioration level (each integrated deterioration level), the life of each of the plurality of switching elements 44a to 44f arranged in the inverter device 1 is determined. It is possible to ensure leveling.

  The inverter device 1 further includes a second flow passage 22 through which the refrigerant flows from the one end 22a toward the other end 22b, and a pump 23 provided in the second flow passage 22 and through which the refrigerant flows. The switching valve 24 is connected to the first port 24 a to which one end 21 a of the first flow passage 21 is connected, the second port 24 b to which the other end 21 b of the first flow passage 21 is connected, and the other end 22 b of the second flow passage 22. When the third port 24c, the fourth port 24d to which the one end 22a of the second flow passage 22 is connected, and when the refrigerant flows through the first flow passage 21 in the first direction D1, the third port 24c and the first port 24a are connected to each other. And when the second port 24b and the fourth port 24d are connected and the refrigerant flows through the first flow passage 21 in the second direction D2, the third port 24c and the second port 24b are connected, and The four-way valve includes a valve body that connects the first port 24a and the fourth port 24d, and a strainer 25 that removes foreign matters in the refrigerant is provided in the fourth port 24d.

  According to this, regardless of whether the refrigerant flows through the first flow path 21 in the first direction D1 or the second direction D2, the refrigerant can be led out from the fourth port 24d. Therefore, the foreign matter in the refrigerant can be reliably removed by arranging the strainer 25 in the fourth port 24d. Moreover, since the number of strainers 25 can be made one, the number of parts of the inverter apparatus 1 can be suppressed. Therefore, cost reduction of the inverter apparatus 1 can be achieved.

<Second embodiment>
Next, the second embodiment of the inverter device of the present invention will be described mainly with respect to differences from the first embodiment described above. When the control device 30 executes the switching control, the flowchart shown in FIG. 5 is executed in the first embodiment described above. Instead, the flowchart shown in FIG. 7 is executed in the second embodiment.

  In the flowchart shown in FIG. 7, steps S202 to 208 are the same as steps S102 to S108 in the flowchart shown in FIG. That is, step S208 in the flowchart of FIG. 7 corresponds to the rising temperature deriving unit of the present invention.

  In step S210, control device 30 derives an integrated temperature of each switching element 44a to 44f (integrated temperature deriving unit). The accumulated temperature is a value obtained by accumulating the rising temperature ΔTh derived by the rising temperature deriving unit (step S208) from the time when the use of the vehicle is started to the present time for each of the plurality of switching elements 44a to 44f. The integrated temperature of each switching element 44a to 44f is stored in the storage unit.

  Subsequently, in step S212, control device 30 determines whether or not the difference between the maximum value and the minimum value of the integrated temperature of each switching element 44a to 44f is equal to or greater than the integrated temperature determination value. When the difference between the integrated temperatures of the switching elements 44a to 44f is relatively small, and the difference between the maximum value and the minimum value of the integrated temperatures of the switching elements 44a to 44f is smaller than the integrated temperature determination value, the control device 30 In step S212, “NO” is determined, and the program is returned to step S202. That is, when the difference between the maximum value and the minimum value of the integrated temperature of each switching element 44a to 44f is smaller than the integrated temperature determination value, control device 30 repeatedly executes steps S202 to S212.

  On the other hand, when the difference between the integrated temperatures of the switching elements 44a to 44f is relatively large, the difference between the maximum value and the minimum value of the integrated temperatures of the switching elements 44a to 44f is equal to or greater than the integrated temperature determination value. The control device 30 determines “YES” in step S212, and advances the program to step S214. The integrated temperature determination value is set by experimental measurement in advance so that the life of each switching element 44a to 44f is leveled. In step S214, the control device 30 switches the refrigerant flow direction (switching control unit), and returns the program to step S202.

  The control device 30 of the second embodiment derives the rising temperature ΔTh of the switching element in the energization mode among the plurality of switching elements 44a to 44f from each element temperature detected by the temperature detection diodes 44a1 to 44f1. An elevated temperature deriving unit (step S208), and an accumulated temperature deriving unit (step S210) for deriving an accumulated temperature obtained by integrating the increased temperature ΔTh derived by the elevated temperature deriving unit for each of the plurality of switching elements 44a to 44f. It has more. The switching control unit (step S214) controls switching of the switching valve 24 from each integrated temperature derived by the integrated temperature deriving unit.

  According to this, since control device 30 controls switching of change-over valve 24 from each integrated temperature of a plurality of switching elements 44a-44f, the life of each of a plurality of switching elements 44a-44f arranged in inverter device 1 Can be more leveled.

  In the above-described embodiment, an example of the inverter device has been described. However, the present invention is not limited to this, and other configurations may be employed. For example, the plurality of switching elements 44a to 44f are arranged in the predetermined arrangement shown in FIG. 1, but instead of this, as shown in FIG. 9, three rows are arranged in parallel in the left-right direction of FIG. You may make it.

  Moreover, in each embodiment mentioned above, although the 1st flow path 21 is provided so that the refrigerant | coolant may flow through the heat radiating member 13 along the left-right direction of FIG. 1, it replaces with this and is shown in FIG. In addition, the refrigerant may flow through the heat dissipating member 13 in a U shape that opens the lower side of FIG.

  Moreover, in each embodiment mentioned above, although the control apparatus 30 acquires the element temperature of each switching element 44a-44f from the forward voltage value of the diode 44a1-44f1 for temperature detection based on a 1st correlation. Instead of this, the voltage values and current values of the switching elements 44a to 44f, the rotational speed of the motor, and the ambient temperature may be acquired based on the fourth correlation. The fourth correlation is a correlation between the voltage value and current value of the switching elements 44a to 44f, the rotational speed of the motor and the ambient temperature, and the element temperature, and is derived by being measured in advance through experiments or the like. In this case, voltage values and current values of the switching elements 44 a to 44 f are input to the control device 30. The inverter device further includes a rotation speed detection sensor (not shown) that is an encoder or the like that detects the rotation speed of the motor, and a temperature sensor (not shown) that detects the ambient temperature of the inverter device. Therefore, in this case, the switching elements 44a to 44f, the rotation speed detection sensor, and the temperature sensor correspond to the temperature detection device of the present invention.

  In each of the above-described embodiments, when the refrigerant flow direction is switched (step S116, step S214), the refrigerant flow is changed to the switching element having the highest element temperature, rising temperature ΔTh, element deterioration degree, integrated deterioration degree, or integrated temperature. You may make it switch the distribution | circulation direction of a refrigerant | coolant so that it may be located in the upstream of a direction. In addition, you may make it stop the drive of the pump 23, while switching the position of a valve body.

  Moreover, in each embodiment mentioned above, although the control apparatus 30 switches the distribution direction of a refrigerant | coolant from each element deterioration degree or each integrated temperature (step S116, step S214), in addition to this, a refrigerant | coolant is whenever a vehicle starts. The distribution direction may be switched.

In each embodiment mentioned above, although a refrigerant is a liquid (antifreeze), it may replace with this and may be gas (air).
Moreover, in each embodiment mentioned above, you may make it provide the several plate member (fin) aiming at increasing the surface area and improving the thermal radiation efficiency in the 2nd surface 13b of the thermal radiation member 13. FIG. In this case, the plurality of plate members constitute the heat radiating portion 13c.

  In the above-described embodiment, the inverter device 1 is applied to a hybrid vehicle. However, the inverter device 1 may be applied to a motor that drives a compressor of an air conditioner instead.

  Further, the number and arrangement of the plurality of switching elements 44a to 44f, the shape and number of the heat radiating members 13, the number and arrangement of the heat radiating portions 13c, the first and second flow passages 21, 22 are within the scope not departing from the gist of the present invention. The shape and the configuration of the inverter circuit 40 may be changed.

  DESCRIPTION OF SYMBOLS 1 ... Inverter apparatus, 10 ... Power module, 12 ... Board | substrate, 13 ... Radiation member, 13c ... Radiation part, 20 ... Cooling device, 21 ... 1st flow path, 22 ... 2nd flow path, 23 ... Pump, 24 ... Switching valve 24a ... first port 24b ... second port 24c ... third port 24d ... fourth port 24e ... first switching channel 24f ... second switching channel 25 ... strainer 26 ... radiator 30 ... Control device, 40 ... Inverter circuit, 44a to 44f ... Switching element, 44a1 to 44f1 ... Temperature detection diode (temperature detection device), D1 ... First direction, D2 ... Second direction, S108, S208 ... Rising temperature deriving unit , S110: Deterioration degree deriving unit, S116, S214: Switching control unit, S210: Integrated temperature deriving unit, ΔTh: Increased temperature

Claims (4)

A plurality of switching elements arranged in a predetermined arrangement;
A plurality of heat dissipating portions that are arranged in a predetermined arrangement corresponding to each of the switching elements, and perform heat dissipation of the switching elements, and
A cooling device for cooling the heat radiation part;
A temperature detecting device for detecting an element temperature of each of the plurality of switching elements;
A control device for controlling at least the cooling device, and an inverter device comprising:
The cooling device is
A flow passage that extends along the arrangement of the heat radiating portions and through which a refrigerant that exchanges heat with the heat radiating portions flows, wherein the refrigerant flows in one direction of the flow passage and in the other of the flow passages. A first flow path that is switchable to a second direction;
A switching valve provided in the first flow path, for switching between the first direction and the second direction,
The controller is
An inverter device comprising: a switching control unit that controls the switching of the switching valve from each element temperature detected by the temperature detection device. The controller is
From each element temperature detected by the temperature detection device, a rising temperature deriving unit for deriving a rising temperature of the switching element in the energization mode among the plurality of switching elements,
Based on the correlation between the rising temperature and the deterioration degree of the switching element, the deterioration degree derivation for deriving the deterioration degree of the switching element for each of the plurality of switching elements from the rising temperature derived by the rising temperature deriving unit. And further comprising
The inverter device according to claim 1, wherein the switching control unit controls the switching of the switching valve based on a degree of deterioration of each switching element derived by the deterioration degree deriving unit. The controller is
From each element temperature detected by the temperature detection device, a rising temperature deriving unit for deriving a rising temperature of the switching element in the energization mode among the plurality of switching elements,
An accumulated temperature deriving unit for deriving an accumulated temperature obtained by accumulating the elevated temperature derived by the elevated temperature deriving unit for each of the plurality of switching elements;
The inverter device according to claim 1, wherein the switching control unit controls the switching of the switching valve from each of the integrated temperatures derived by the integrated temperature deriving unit. A second flow path through which the refrigerant flows from one end to the other;
A pump provided in the second flow path for circulating the refrigerant;
The switching valve is
A first port to which one end of the first flow path is connected;
A second port to which the other end of the first flow path is connected;
A third port to which the other end of the second flow path is connected;
A fourth port to which the one end of the second flow passage is connected;
When circulating the refrigerant in the first direction in the first flow path, connect the third port and the first port, and connect the second port and the fourth port,
A valve body that connects the third port and the second port, and connects the first port and the fourth port when the refrigerant flows through the first flow passage in the second direction; And a four-way valve with
The inverter device according to any one of claims 1 to 3, wherein a strainer that removes foreign matters in the refrigerant is provided in the fourth port.

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