JP2021124457A - Power cycle test device and power cycle test method - Google Patents

Abstract

To provide a power cycle test device and a power cycle test method that are capable of efficiently performing a power cycle test.SOLUTION: A power cycle test device comprises: a current application unit that applies a current to a specimen; a cooling medium temperature adjusting unit that adjusts the temperature of a cooling medium for cooling the specimen; a cooling unit that cools the specimen with the cooling medium of which temperature is adjusted by the cooling medium temperature adjusting unit; a circulation circuit that circulates the cooling medium between the cooling medium temperature adjusting unit and the cooling unit; a bypass route connected to the circulation circuit so as to bypass the cooling unit; a switching part for switching a state of the cooling medium flowing into the bypass route; a current application control unit that controls the current application unit so that a power cycle test is performed in which current application to the specimen and stop of the application are repeated; and a switching control unit that controls the switching part according to a predetermined timing in the power cycle test.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power cycle test apparatus and a power cycle test method.

Conventionally, as described in Patent Document 1, a power for testing the reliability of various devices by applying a thermal shock to a test body such as a power semiconductor by repeatedly applying a current and stopping the current. Cycle tests are known. In this power cycle test, the internal heat generation and cooling of the test piece are repeated by the cycle of applying and stopping the electric current, and the joint part in the test piece is deteriorated by the stress caused by the difference in the coefficient of linear expansion. The thermal shock resistance of the body is evaluated.

Patent Document 1 describes a water-cooled heat sink type power cycle test apparatus. This power cycle test device sends an electric current to the cooling plate on which the test power device is mounted, the chiller, the circulating water pipe that circulates the water temperature controlled by the chiller between the cooling plate, and the test power device. It includes a current source to be applied and a control power device for controlling application and interruption of current to the test power device.

Japanese Patent No. 5731448

In Patent Document 1, the temperature of the junction of the device is repeatedly raised and lowered by repeatedly turning on / off the current application to the test power device, but the following situations may occur. For example, the temperature of the joint may rise slowly because the cooling water is supplied to the cooling plate even when the current application, which does not require cooling by the cooling water, is turned on. For this reason, conventionally, the test time of the power cycle test becomes long, and there is a possibility that the test cannot be performed efficiently.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power cycle test apparatus and a power cycle test method capable of efficiently performing a power cycle test.

The power cycle test apparatus according to one aspect of the present invention includes a current application unit that applies a current to the test body, a cooling medium temperature control unit that controls the temperature of the cooling medium for cooling the test body, and the cooling medium temperature. A cooling unit that cools the test piece with the cooling medium that has been temperature-controlled by the control unit, a circulation circuit that circulates the cooling medium between the cooling medium temperature control unit and the cooling unit, and a bypass of the cooling unit. A power cycle test by repeatedly applying a current to the test piece and stopping the bypass path connected to the circulation circuit, a switching unit for switching the inflow state of the cooling medium into the bypass path, and the test piece. A current application control unit that controls the current application unit and a switching control unit that controls the switching unit according to a predetermined timing in the power cycle test are provided.

According to this power cycle test apparatus, it is possible to execute a power cycle test by repeatedly applying a current to a test piece and stopping the current, and to control a switching unit according to a predetermined timing in the power cycle test. As a result, during the power cycle test, the inflow state of the cooling medium into the bypass path can be appropriately switched according to the timing of whether or not the cooling medium needs to be supplied to the cooling unit. Therefore, according to the power cycle test apparatus of the present invention, the power cycle test can be efficiently performed.

In the power cycle test apparatus, in the power cycle test, when a current is applied from the current application unit to the test body, the cooling medium flows into the bypass path and the current is applied. The switching unit may be controlled so that the cooling medium does not flow into the bypass path when the application of the current from the unit to the test piece is stopped.

According to this configuration, it is possible to suppress the increase in the joint temperature from being hindered by the cooling water when a current is applied to the test piece.

In the power cycle test apparatus, the switching control unit may be configured to control the switching unit based on a measured value of the joint temperature of the test piece.

According to this configuration, the inflow state of the cooling medium into the bypass path can be appropriately switched by using the measured value of the joint temperature of the test piece as an index, so that the joint temperature can be controlled more reliably during the power cycle test. Becomes possible.

In the power cycle test apparatus, in the switching control unit, the measured value of the joint temperature is the target value of the joint temperature based on the comparison between the measured value of the joint temperature and the target value of the joint temperature. It may be configured to control the switching unit so as to approach.

According to this configuration, the inflow state of the cooling medium into the bypass path can be appropriately switched based on the difference between the measured value of the joint temperature and the target value, so that the joint temperature is set to the target value during the power cycle test. Can be controlled more reliably.

In the power cycle test apparatus, the switching control unit is configured to control the switching unit so that the inflow state of the cooling medium into the bypass path is switched at a predetermined timing in the power cycle test. You may. The timing may be predetermined based on the time change of the joint temperature of the test piece when the current is applied to the test piece.

According to this configuration, the inflow state of the cooling medium into the bypass path is switched at an appropriate timing during the power cycle test without performing arithmetic processing for comparing the measured value of the joint temperature with the target value. be able to.

In the power cycle test apparatus, the switching unit is supplied to the cooling unit and the flow rate of the cooling medium flowing into the bypass path among the cooling media flowing out from the cooling medium temperature control unit to the circulation circuit. The ratio with the flow rate of the cooling medium may be adjustable.

According to this configuration, the amount of the cooling medium flowing into the bypass path can be finely adjusted, so that the joint temperature can be controlled with higher accuracy during the power cycle test.

The power cycle test apparatus may further include a discharge mechanism for discharging the cooling medium from the inside of the cooling unit.

According to this configuration, when it is not necessary to cool the test piece by the cooling medium, the cooling medium can be discharged from the cooling unit, and the residual cooling medium can be suppressed in the cooling unit.

In the power cycle test apparatus, the discharge mechanism may include a gas supply source that supplies gas to the inside of the cooling unit.

According to this configuration, by sending gas from the gas supply source into the cooling unit and pushing out the cooling medium, the cooling medium in the cooling unit can be discharged more reliably.

The power cycle test apparatus may further include an emission control unit that controls the emission mechanism. The switching control unit may be configured to control the switching unit so that the cooling medium flows into the bypass path after the end timing of the power cycle test. The discharge control unit may be configured to operate the discharge mechanism after the switching unit is switched so that the cooling medium flows into the bypass path after the end timing.

According to this configuration, after the power cycle test is completed, the inflow of the cooling medium into the cooling unit is stopped, the cooling medium remaining in the cooling unit is discharged, and the residual cooling medium in the cooling unit can be suppressed.

The power cycle test apparatus may further include a chamber in which the test piece is housed. The timing at which the discharge control unit operates the discharge mechanism may be configured to be after the temperature in the chamber reaches the temperature of the cooling medium.

According to this configuration, when the thermal cycle test in which the temperature in the chamber is periodically changed is carried out in synchronization with the power cycle test, the cooling medium remaining in the cooling unit becomes a heat load and the test piece is subjected to the thermal cycle. It is possible to suppress the inhibition of the temperature control of.

The power cycle test method according to another aspect of the present invention is a method of executing a power cycle test by repeatedly applying a current to a test piece and stopping the current. In this method, the inflow state of the cooling medium into the cooling unit that cools the test piece is switched according to a predetermined timing in the power cycle test.

According to this method, during the power cycle test, the inflow state of the cooling medium to the cooling unit can be appropriately switched according to the timing of whether or not the cooling medium needs to be supplied to the cooling unit. Therefore, according to the power cycle test method of the present invention, the power cycle test can be efficiently performed.

As is clear from the above description, according to the present invention, it is possible to provide a power cycle test apparatus and a power cycle test method capable of efficiently performing a power cycle test.

It is a figure which shows typically the structure of the power cycle test apparatus which concerns on Embodiment 1 of this invention. It is a timing chart for demonstrating the power cycle test method which concerns on Embodiment 1 of this invention. It is a flowchart for demonstrating the power cycle test method which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the flow of the cooling medium during the current application of the power cycle test method which concerns on Embodiment 1 of this invention. It is a block diagram for demonstrating the structure of the control part in the power cycle test apparatus which concerns on Embodiment 2 of this invention. It is a timing chart for demonstrating the power cycle test method which concerns on Embodiment 2 of this invention. It is a figure which shows typically the structure of the power cycle test apparatus which concerns on Embodiment 4 of this invention. It is a timing chart for demonstrating the superimpose test in Embodiment 4 of this invention. It is a schematic diagram for demonstrating the flow of a cooling medium and compressed air in the power cycle test apparatus which concerns on Embodiment 4 of this invention. It is a figure which shows typically the structure of the power cycle test apparatus which concerns on other embodiment of this invention. It is a figure which shows typically the structure of the power cycle test apparatus which concerns on other embodiment of this invention. It is a timing chart for demonstrating the superimpose test in other embodiment of this invention.

Hereinafter, the power cycle test apparatus and the power cycle test method according to the embodiment of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
<Power cycle test equipment>
First, the configuration of the power cycle test apparatus 1 according to the first embodiment of the present invention will be described with reference to FIG. The power cycle test device 1 is a device for testing the reliability of the test body 100 by repeatedly applying a current I to the test body 100 and stopping the current I to give a thermal shock to the test body 100. The test body 100 is, for example, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a power transistor, and the like, but is not limited thereto.

As shown in FIG. 1, the power cycle test apparatus 1 includes a current application unit 60, a cooling medium temperature control unit 20, a cooling unit 10, a circulation circuit 30, a bypass path 42, and a first switching unit 40. It mainly includes a second switching unit 41, a discharge mechanism 50, a collection path 44, a reservoir tank 43, and a controller 70. Hereinafter, each of these components will be described.

The current application unit 60 is a power source that applies a current I to the test piece 100. The timing of applying the current from the current applying unit 60 to the test piece 100 and the magnitude of the applied current are controlled by the controller 70.

The cooling medium temperature control unit 20 controls the temperature of the cooling medium for cooling the test piece 100 during the power cycle test, and is composed of a chiller. The cooling medium is, for example, water (cooling water), but is not limited thereto. As shown in FIG. 1, the housing of the cooling medium temperature control unit 20 is provided with an inlet 22 for the cooling medium and an outlet 21 for the cooling medium, respectively. Further, in the housing, a refrigerator for cooling the cooling medium, a heater for heating the cooling medium, and a liquid feeding pump for delivering the temperature-controlled cooling medium are installed, respectively. The cooling medium temperature control unit 20 in the present embodiment constantly operates the refrigerator at a constant output and adjusts the temperature of the cooling medium by the output of the heater, but the present invention is not limited to this.

The cooling unit 10 is a water-cooled heat sink that cools the test body 100 with the cooling medium temperature-controlled by the cooling medium temperature control unit 20. Specifically, the cooling unit 10 is used to quickly lower the temperature of the test piece 100 while the current application is stopped. The cooling unit 10 is a plate made of a metal material having high thermal conductivity, has a mounting surface 10A on which the test body 100 is mounted, and has a flow path 11 through which a cooling medium flows. The test body 100 is cooled by heat dissipation from the test body 100 to the cooling medium flowing inside the cooling unit 10. As shown in FIG. 1, the cooling unit 10 is provided with an inlet 12 of the cooling medium and an outlet 13 of the cooling medium, respectively.

The circulation circuit 30 is for circulating the cooling medium between the cooling medium temperature control unit 20 and the cooling unit 10. As shown in FIG. 1, the circulation circuit 30 includes a supply path 31 connecting the outlet 21 of the cooling medium temperature control unit 20 and the inlet 12 of the cooling unit 10, and the inlet 22 and the cooling unit 10 of the cooling medium temperature control unit 20. Includes a return path 32 that connects to the exit 13 of. The supply path 31 and the return path 32 are composed of pipes in which a flow path through which the cooling medium flows is formed.

The bypass path 42 is connected to the circulation circuit 30 so as to bypass the cooling unit 10, and is composed of a pipe having a flow path through which the cooling medium flows. The first switching unit 40 is a three-way valve (flow path switching valve) installed in the supply path 31, and switches the inflow state of the cooling medium from the supply path 31 to the bypass path 42.

More specifically, the supply path 31 is the first supply path 31A on the upstream side (cooling medium temperature control section 20 side) of the first switching section 40 and the downstream side (cooling section 10) of the first switching section 40. Includes the second supply path 31B on the side). The first switching unit 40 is provided with three ports (inlet port 40A, first exit port 40B, and second exit port 40C). As shown in FIG. 1, the upstream end of the first supply path 31A is connected to the outlet 21 of the cooling medium temperature control section 20, and the downstream end of the first supply path 31A is connected to the inlet port 40A of the first switching section 40. It is connected. The upstream end of the second supply path 31B is connected to the first outlet port 40B of the first switching unit 40, and the downstream end of the second supply path 31B is connected to the inlet 12 of the cooling unit 10. The upstream end of the bypass path 42 is connected to the second exit port 40C of the first switching unit 40.

The first switching unit 40 is controlled by the controller 70 to provide a supply state in which the inlet port 40A and the first outlet port 40B communicate with each other and a bypass state in which the inlet port 40A and the second exit port 40C communicate with each other. Switch between. In the supply state, the cooling medium flowing out from the outlet 21 of the cooling medium temperature control section 20 flows into the second supply path 31B from the first supply path 31A via the first switching section 40, but goes into the bypass path 42. Does not flow. On the other hand, in the bypass state, the cooling medium flowing out from the outlet 21 of the cooling medium temperature control section 20 flows into the bypass path 42 from the first supply path 31A via the first switching section 40, but the second supply path 31B. Does not flow into. That is, in the bypass state, the cooling medium flowing out from the outlet 21 of the cooling medium temperature control unit 20 returns to the inlet 22 of the cooling medium temperature control unit 20 without passing through the cooling unit 10 (bypassing the cooling unit 10). ..

The second switching unit 41 is a three-way valve configured in the same manner as the first switching unit 40, and is installed in the return path 32. The return path 32 is a first return path 32A on the upstream side (cooling section 10 side) of the second switching section 41 and a second return on the downstream side (cooling medium temperature control section 20 side) of the second switching section 41. Includes route 32B.

The second switching unit 41 is provided with three ports (inlet port 41A, first exit port 41B, and second exit port 41C). The upstream end of the first return path 32A is connected to the outlet 13 of the cooling unit 10, and the downstream end of the first return path 32A is connected to the inlet port 41A of the second switching unit 41. The upstream end of the second return path 32B is connected to the first outlet port 41B of the second switching unit 41, and the downstream end of the second return path 32B is connected to the inlet 22 of the cooling medium temperature control unit 20. The downstream end of the bypass path 42 is connected to the second return path 32B.

The discharge mechanism 50 is for discharging the cooling medium from the inside (flow path 11) of the cooling unit 10. As shown in FIG. 1, the discharge mechanism 50 in the present embodiment includes a branch path 51 that branches from the second supply path 31B, an opening / closing valve 52 that opens and closes the flow path in the branch path 51, and a branch path 51 that is the first of the branch paths 51. 2 The gas supply source 53 provided at the end opposite to the end connected to the supply path 31B is included. The gas supply source 53 is, for example, an air compressor, and supplies gas (compressed air) into the flow path 11 of the cooling unit 10 via the branch path 51 and the second supply path 31B. As a result, the cooling medium in the cooling unit 10 is pushed out by the compressed air and discharged to the outside of the cooling unit 10. The gas sent into the cooling unit 10 is not limited to air.

The recovery path 44 is a path for recovering the cooling medium discharged from the cooling unit 10. As shown in FIG. 1, the upstream end of the recovery path 44 is connected to the second outlet port 41C of the second switching section 41, and the downstream end of the recovery path 44 is a supply port provided in the cooling medium temperature control section 20. It is connected to 23.

The reservoir tank 43 is for storing the cooling medium discharged from the cooling unit 10 by the discharge mechanism 50. The reservoir tank 43 is, for example, an open type tank and is installed in the recovery path 44. The recovery path 44 and the reservoir tank 43 are not essential components in the present invention and may be omitted.

The second switching unit 41 is controlled by the controller 70 to have a return state in which the inlet port 41A and the first exit port 41B communicate with each other and a collection state in which the inlet port 41A and the second exit port 41C communicate with each other. It switches between. In the return state, the cooling medium flowing out from the outlet 13 of the cooling unit 10 flows from the first return path 32A to the second return path 32B via the second switching unit 41, but does not flow into the recovery path 44. On the other hand, in the recovery state, the cooling medium flowing out from the outlet 13 of the cooling unit 10 flows into the recovery path 44 from the first return path 32A via the second switching unit 41, but flows into the second return path 32B. do not. That is, when the cooling medium is collected in the reservoir tank 43, the second switching unit 41 switches to the collection state.

The controller 70 is for controlling various operations of the power cycle test apparatus 1, and includes a current application control unit 71, a first switching control unit 72, a second switching control unit 73, an emission control unit 74, and the like. Includes a chiller control unit 75. The current application control unit 71, the first switching control unit 72, the second switching control unit 73, the discharge control unit 74, and the chiller control unit 75 are executed by the central processing unit (CPU) of the controller 70, respectively. It is a function.

The current application control unit 71 controls the current application unit 60 so that the power cycle test is executed by repeatedly applying the current I to the test body 100 and stopping the current I. The first switching control unit 72 switches the first switching unit 40 between the supply state and the bypass state. The second switching control unit 73 switches the second switching unit 41 between the return state and the recovery state. The discharge control unit 74 controls the discharge mechanism 50, and specifically switches the opening and closing of the on-off valve 52. The chiller control unit 75 controls the operation of the cooling medium temperature control unit 20.

The first switching control unit 72 controls the first switching unit 40 according to a predetermined timing in the power cycle test. More specifically, in the power cycle test, the first switching control unit 72 causes the cooling medium to flow into the bypass path 42 and the current application unit when the current I is applied from the current application unit 60 to the test body 100. The first switching unit 40 is controlled so that the cooling medium does not flow into the bypass path 42 when the application of the current I from the 60 to the test piece 100 is stopped. Hereinafter, the specific contents of this control will be described with reference to the timing chart of FIG. 2 and the flowchart of FIG.

<Power cycle test method>
The power cycle test method according to this embodiment, which is carried out by the controller 70, will be described. This power cycle test method is carried out by using the power cycle test apparatus 1, executing a power cycle test by repeatedly applying a current I to the test body 100 and stopping the current I, and a predetermined power cycle test. This includes switching the inflow state of the cooling medium into the cooling unit 10 (the inflow state of the cooling medium into the bypass path 42) according to the timing. Specifically, it is as described below.

In FIG. 1, the flow of the cooling medium when the application of the current to the test piece 100 is stopped is indicated by the broken line arrow. On the other hand, in FIG. 4, the flow of the cooling medium when a current is applied to the test piece 100 is indicated by a broken line arrow. Further, in FIG. 2, the horizontal axis shows time, the upper graph shows the time change of the junction temperature (junction temperature, Tj temperature) of the test piece 100, and the middle graph shows the on / on / of current application to the test piece 100. The off timing is shown, and the lower graph shows the on / off timing of the inflow of the cooling medium into the bypass path 42.

First, the current application control unit 71 controls the current application unit 60 and starts applying the current to the test piece 100 (time t1 in FIG. 2 and step S10 in FIG. 3). As a result, heat is generated inside the test body 100, and the junction temperature of the test body 100 rises toward the first set temperature. During the time t1 to t2 in FIG. 2, the current I applied to the test piece 100 is constant.

Then, while starting the application of the current to the test body 100, the first switching control unit 72 switches the first switching unit 40 from the supply state (FIG. 1) to the bypass state (FIG. 4) (step S20 in FIG. 3). .. As a result, the cooling medium flowing out from the outlet 21 of the cooling medium temperature control section 20 flows in this order through the first supply path 31A, the bypass path 42, and the second return path 32B, and returns to the inlet 22 of the cooling medium temperature control section 20. As described above, since the cooling medium is not supplied to the cooling unit 10 while the test body 100 is energized, it is possible to suppress the increase in the junction temperature of the test body 100 from being hindered by the cooling medium.

When the junction temperature becomes equal to or higher than the first set temperature (time t2 in FIG. 2, YES in step S30 in FIG. 3), the current application control unit 71 controls the current application unit 60 and stops the current application to the test piece 100. (Step S40 in FIG. 3). At the same time, the first switching control unit 72 switches the first switching unit 40 from the bypass state (FIG. 4) to the supply state (FIG. 1) (step S50 in FIG. 3).

As a result, heat generation inside the test body 100 is stopped, and the junction temperature drops toward the second set temperature (a temperature lower than the first set temperature and near room temperature). At this time, since the first switching unit 40 is switched to the supply state (FIG. 1), the cooling medium flowing out from the outlet 21 of the cooling medium temperature control unit 20 goes through the first supply path 31A and the second supply path 31B in order. It flows and flows into the flow path 11 of the cooling unit 10. As a result, heat is dissipated from the test body 100 to the cooling medium in the cooling unit 10, and the junction temperature rapidly drops toward the second set temperature.

When the junction temperature drops below the second set temperature (time t3 in FIG. 2, YES in step S60 in FIG. 3), one cycle in the power cycle test ends, and the process in the controller 70 counts the number of test cycles by 1. Is added (step S70 in FIG. 3). Then, the test cycle (time t1 to t3 in FIG. 2, steps S10 to S70 in FIG. 3) is repeated until the count of the test cycle reaches the set cycle. When the test cycle count reaches the set cycle (YES in step S80 of FIG. 3), the power cycle test ends.

As described above, according to the power cycle test apparatus 1 according to the present embodiment, the power cycle test is executed by repeatedly applying the current I to the test body 100 and stopping the current I, and at a predetermined timing in the power cycle test. The first switching unit 40 is switched between the supply state and the bypass state accordingly. Specifically, when the current is applied to the test body 100, the first switching unit 40 is switched to the bypass state (FIG. 4), and when the current application to the test body 100 is stopped, the first switching unit 40 is in the supply state (FIG. 4). It can be switched to 1). As a result, the increase in the junction temperature of the test body 100 is suppressed from being hindered by the cooling medium in the cooling unit 10, and the junction temperature can be rapidly increased to the first set temperature. Moreover, by providing the bypass path 42, it is possible to stop the inflow of the cooling medium into the cooling unit 10 while continuing the operation of the cooling medium temperature control unit 20 even when the current is applied to the test body 100. Therefore, the burden on the device of the cooling medium temperature control unit 20 is smaller than that in the case where the operation and stop of the cooling medium temperature control unit 20 are repeated according to the on / off of the current application to the test body 100. Therefore, according to the power cycle test apparatus 1 according to the present embodiment, it is possible to efficiently perform the power cycle test of the test body 100.

<Modification example>
Examples of modifications of the first embodiment include the following forms.

In the first embodiment, the application of the current to the test piece 100 is stopped based on the fact that the junction temperature rises to the first set temperature or higher, and the junction temperature drops to the second set temperature or lower to the test piece 100. Resuming current application, but not limited to this. For example, based on the elapse of the first set time from the start of one cycle of the power cycle test, the current application to the test piece 100 is stopped, and the first switching unit 40 is switched from the bypass state to the supply state. May be good. Then, based on the lapse of the second set time (a time longer than the first set time) from the start of the cycle of the power cycle test, the current application to the test piece 100 is restarted, and the first switching unit 40 May be switched from the supply state to the bypass state.

(Embodiment 2)
Next, the power cycle test apparatus and the power cycle test method according to the second embodiment of the present invention will be described with reference to FIGS. 1, 5 and 6. The power cycle test apparatus and the power cycle test method according to the second embodiment are basically the same as those in the first embodiment, but the first switching control unit 72 is the first based on the measured value of the junction temperature of the test body 100. It differs in that it controls the switching unit 40. Hereinafter, only the points different from the first embodiment will be described.

FIG. 5 is a functional block diagram for explaining the configuration of the controller 70A in the second embodiment. The controller 70A in the present embodiment also includes the current application control unit 71, the second switching control unit 73, the discharge control unit 74, and the chiller control unit 75, as in the first embodiment, but these are omitted in FIG. ing.

The controller 70A includes a reception unit 76, a storage unit 77, and a determination unit 78. The reception unit 76 and the determination unit 78 are functions executed by the CPU of the controller 70A. Further, the storage unit 77 is composed of storage devices such as various memories.

The reception unit 76 receives the data of the measured value of the junction temperature of the test piece 100. The measured value of the junction temperature is detected by the temperature detection unit 110 built in the test body 100, and the detection signal is transmitted to the reception unit 76. The temperature detection unit 110 measures the junction temperature of the test piece 100 at all times or at predetermined time intervals.

The storage unit 77 stores the target value of the junction temperature of the test piece 100. As shown by the broken line in the upper graph of FIG. 6, this target value changes periodically with the elapsed time during the power cycle test (horizontal axis of the graph).

The determination unit 78 compares the measured value of the junction temperature with the target value thereof, and determines the magnitude relationship between them. Then, the first switching control unit 72 controls the first switching unit 40 so that the measured value of the junction temperature approaches the target value based on the determination result by the determination unit 78. Hereinafter, the specific contents of this control will be described with reference to the timing chart of FIG.

FIG. 6 shows the time change (upper graph) of the measured value of the junction temperature (Tj temperature) and its target value, and the on / off timing of the current application to the test piece 100 for one current application cycle in the power cycle test. The middle graph) and the on / off timing of the inflow of the cooling medium into the bypass path 42 (lower graph) are shown. In the upper graph, the measured value of the junction temperature is shown by a solid line, and the target value of the junction temperature is shown by a broken line. Similar to the first embodiment, the power cycle test is started by applying a current to the test body 100 (time t1 in FIG. 6), and at the same time, the first switching unit 40 switches from the supply state to the bypass state.

As shown in FIG. 6, during the time t1 to t2, the measured value of the junction temperature is smaller than the target value. During this time, the first switching control unit 72 maintains the first switching unit 40 in the bypass state based on the determination result (target value> measured value) by the determination unit 78. As a result, the inflow of the cooling medium into the cooling unit 10 is stopped, so that the upward gradient of the junction temperature gradually increases. Then, the measured value of the junction temperature approaches the target value, and becomes the same as the target value at the time t2 in FIG.

During the time t2 to t3 in FIG. 6, the measured value of the junction temperature is larger than the target value. During this time, the first switching control unit 72 maintains the first switching unit 40 in the supply state based on the determination result (target value <measured value) by the determination unit 78. As a result, the cooling medium flows into the cooling unit 10, and the heat inside the test piece 100 is taken away by the cooling medium, so that the rising gradient of the junction temperature gradually becomes smaller. Then, the measured value of the junction temperature approaches the target value and becomes the same as the target value at the time t3 in FIG.

During the time t3 to t4 in FIG. 6, the measured value of the junction temperature is smaller than the target value as in the time period t1 to t2. Therefore, the first switching control unit 72 maintains the first switching unit 40 in the bypass state based on the determination result (target value> measured value) by the determination unit 78. As described above, in the second embodiment, unlike the case where the first switching unit 40 is always maintained in the bypass state when the current is applied to the test body 100 as in the first embodiment, when the current is applied to the test body 100 (FIG. Also during the time t1 to t4 in 6), the first switching unit 40 is switched between the supply state and the bypass state based on the comparison between the measured value of the junction temperature and the target value thereof.

As described above, in the second embodiment, the first step is performed during the power cycle test, using the measured value of the junction temperature of the test body 100 as an index, and more specifically, based on the difference between the measured value of the junction temperature and the target value thereof. The switching unit 40 is controlled. This makes it possible to bring the junction temperature closer to the target temperature more reliably, and it becomes possible to carry out the power cycle test under more appropriate conditions.

(Embodiment 3)
Next, the power cycle test apparatus and the power cycle test method according to the third embodiment of the present invention will be described. In the present embodiment, the first switching control unit 72 controls the first switching unit 40 so that the inflow state of the cooling medium into the bypass path 42 is switched at a predetermined timing in the power cycle test. Specifically, it is as follows.

First, the timing is predetermined based on the time change of the junction temperature of the test body 100 when the current is applied to the test body 100, and the information is stored in the storage unit 77 (FIG. 5). .. That is, the measured value of the junction temperature when the current is applied to the test piece 100 (solid line in the upper graph in FIG. 6) and the target value of the junction temperature (broken line in the graph) are compared, and both values match. The timing (time t2, t3 in FIG. 6) is predetermined, and the information is stored in the storage unit 77.

Then, the first switching control unit 72 controls the first switching unit 40 based on the predetermined timing during the power cycle test. Specifically, the first switching unit 40 is switched from the bypass state to the supply state at the timing of time t2 in FIG. 6, and the first switching unit 40 is switched from the supply state to the bypass state at the timing of time t3 in the figure. .. The current value applied to the test body 100 during the power cycle test is the same as the current value applied to the test body 100 when determining the switching timing.

As described above, in the third embodiment, the state of the first switching unit 40 is switched at a predetermined timing during the power cycle test without using the measured value or the target value of the junction temperature as an index. As a result, the inflow state of the cooling medium into the bypass path 42 can be switched at an appropriate timing without performing arithmetic processing for comparing the measured value of the junction temperature with the target value thereof.

(Embodiment 4)
Next, the power cycle test apparatus and the power cycle test method according to the fourth embodiment of the present invention will be described with reference to FIGS. 7 and 8. The power cycle test apparatus and power cycle test method according to the fourth embodiment are basically the same as those of the first to third embodiments, but the thermal inside the chamber 80 in which the test body 100 is housed is periodically changed. The difference is that the cycle test is performed in synchronization with the power cycle test. Hereinafter, only the points different from the above-described first to third embodiments will be described.

As shown in FIG. 7, the power cycle test apparatus according to the present embodiment includes a chamber 80 in which the test body 100 is housed, a chamber temperature control unit 82 for controlling the temperature of air in the chamber 80, and a chamber temperature control unit 82. It is provided with a blower portion 85 such as a fan that circulates the air temperature-controlled by the chamber 80 in the chamber 80, and a controller 70B. The chamber temperature control unit 82 includes a heater 83 that heats the air in the chamber 80, and a cooler 84 (evaporator) of the refrigerator that cools the air. The space inside the chamber 80 is partitioned by a partition plate 81 into a test chamber 80A in which the test body 100 is housed and an air conditioning chamber 80B in which the chamber temperature control portion 82 and the blower portion 85 are installed. The cooling mechanism for cooling the air in the chamber 80 is not limited to the refrigerator.

In addition to the configurations described in the first and second embodiments, the controller 70B further includes a chamber temperature control unit 79 that controls the chamber temperature control unit 82. The chamber temperature control unit 79 controls the outputs of the heater 83 and the cooler 84 so that the temperature detected by the temperature sensor 86 (measured value of the temperature in the test chamber 80A) approaches the target temperature. The chamber temperature control unit 79 is a function executed by the CPU of the controller 70B.

The power cycle test apparatus according to the present embodiment is configured to be capable of performing a superimpose test in which a power cycle test and a thermal cycle test are synchronized. FIG. 8 shows the time change of the temperature in the chamber 80 (upper graph), the on / off timing of the current application to the test piece 100 (middle graph), and the cooling medium to the bypass path 42 in the superimpose test. The inflow on / off timing (lower graph) is shown. The time t1 to t2 in the figure is, for example, 2 minutes or more and 5 minutes or less, but is not limited to this. Further, the power cycle test apparatus of the present invention is not limited to the one that synchronizes the power cycle test and the thermal cycle test, and may perform the power cycle test in a state where the temperature in the chamber 80 is kept constant.

As shown in FIG. 8, the chamber temperature control unit 79 controls the chamber temperature control unit 82 so that the temperature inside the chamber 80 changes periodically between the lower limit temperature and the upper limit temperature. The current application control unit 71 (FIG. 1) starts the power cycle test at the timing when the temperature inside the chamber 80 turns upward (time t1 in FIG. 8), and at the same time when the temperature inside the chamber 80 turns downward. The current application unit 60 (FIG. 1) is controlled so that the power cycle test ends at (time t2 in FIG. 8).

The first switching control unit 72 (FIG. 1) controls the first switching unit 40 so that the cooling medium flows into the bypass path 42 after the end timing of the power cycle test. Specifically, during the power cycle test (during time t1 to t2 in FIG. 8), the first switching unit 40 is maintained in the supply state, and at the end of the power cycle test (time t2 in FIG. 8). , The first switching control unit 72 switches the first switching unit 40 from the supply state to the bypass state.

The discharge control unit 74 (FIG. 1) operates the discharge mechanism 50 after the first switching unit 40 is switched so that the cooling medium flows into the bypass path 42 after the end timing of the power cycle test. Specifically, the discharge control unit 74 operates the discharge mechanism 50 when the temperature in the chamber 80 turns downward and becomes lower than the temperature of the cooling medium (time t3 in FIG. 8). (Open the open / close valve 52). Further, at the timing of operating the discharge mechanism 50, the second switching control unit 73 switches the second switching unit 41 from the return state to the recovery state.

FIG. 9 shows the flow of the cooling medium and the compressed air in the power cycle test apparatus during the time t3 to t4 in FIG. 8, respectively. In the figure, the flow of the cooling medium is indicated by a broken line arrow, and the flow of compressed air is indicated by a solid line arrow.

As shown in FIG. 9, during the time t3 to t4, the cooling medium flows out from the outlet 21 of the cooling medium temperature control unit 20 and then flows in the first supply path 31A, the bypass path 42, and the second return path 32B in this order. Since it returns to the inlet 22, it is not supplied to the cooling unit 10. On the other hand, the compressed air is sent from the gas supply source 53 to the inside of the cooling unit 10 (flow path 11) via the branch path 51 and the second supply path 31B.

As a result, the cooling medium remaining in the cooling unit 10 is pushed out to the first return path 32A by the compressed air. This cooling medium flows into the recovery path 44 from the first return path 32A and is stored in the reservoir tank 43. Then, the cooling medium collected in the reservoir tank 43 is returned to the cooling medium temperature control unit 20 from the supply port 23. The compressed air does not necessarily have to be constantly supplied during the time t3 to t4 in FIG. 8, and the supply of the compressed air is stopped at the timing when it is considered that all the cooling water in the cooling unit 10 has been discharged. May be good.

As described above, in the present embodiment, in the superimpose test in which the power cycle test and the thermal cycle test are synchronized, when the temperature in the chamber 80 is equal to or lower than the temperature of the cooling medium after the completion of the power cycle test. The discharge mechanism 50 is operated to discharge the cooling medium in the cooling unit 10. As a result, it is possible to prevent the cooling medium remaining in the cooling unit 10 from becoming a heat load and hindering the temperature control of the test body 100 by the thermal cycle test.

(Other embodiments)
Here, other embodiments of the present invention will be described.

As shown in FIG. 10, one end of the branch path 51 may be connected to the second supply path 31B, and the other end of the branch path 51 may be open to the atmosphere. In this case, the cooling medium in the cooling unit 10 can be discharged by opening the on-off valve 52 and sending air into the cooling unit 10 by atmospheric pressure.

As shown in FIG. 11, a pump 44A that sucks the cooling medium from the inside of the cooling unit 10 may be installed in the recovery path 44. By operating the pump 44A when the discharge mechanism 50 is operated, the cooling medium in the cooling unit 10 can be discharged more reliably. The pump 44A may be installed in the first return path 32A.

In the fourth embodiment, the power cycle test is started at the timing when the temperature inside the chamber turns upward in the superimpose test, and the power cycle test is finished at the timing when the temperature inside the chamber turns downward, but the present invention is limited to this. Not done. For example, as shown in FIG. 12, in the superimpose test, even if the power cycle test is started at the timing when the chamber temperature turns downward and the power cycle test is finished at the timing when the chamber temperature turns upward. good. In this case, the discharge mechanism 50 may be operated after the time t2 in FIG. 12 (after the inflow of the cooling medium into the bypass path 42 is started), or after the time t3 in the figure (the temperature inside the chamber rises). The discharge mechanism 50 may be operated (after the temperature of the cooling medium is reached).

In the fourth embodiment, the case where the first switching unit 40 is switched to the bypass state at the same time as the end of the power cycle test in the superimpose test has been described, but the power cycle test is carried out without synchronizing with the thermal cycle test. In this case, the first switching unit 40 may be switched to the bypass state at the same time as the end of the power cycle test. This also applies to the case of FIG.

In the fourth embodiment (FIG. 8), the cooling medium is supplied to the cooling unit 10 during the execution of the power cycle test in the superimpose test, but the present invention is not limited to this, and the first method is performed during the execution of the power cycle test. The switching unit 40 may be in a bypass state. Further, during the execution of the power cycle test, the first switching unit 40 may be appropriately switched between the supply state and the bypass state in accordance with the timing of applying the current to the test body 100. This also applies to the case of FIG.

In the superimpose test of the fourth embodiment, the first switching unit 40 is maintained in the supply state (bypass OFF) during the time t2 to t3 in FIG. 8, and the first switching is performed at the discharge timing of the cooling water at the time t3. The unit 40 may be switched from the supply state to the bypass state. This also applies to the case of FIG.

The first switching unit 40 is supplied to the flow rate of the cooling medium flowing into the bypass path 42 and the cooling unit 10 among the cooling media flowing out from the cooling medium temperature control unit 20 to the circulation circuit 30 (first supply path 31A). The ratio with the flow rate of the cooling medium may be adjustable. Specifically, the upstream end of the bypass path 42 is connected to the supply path 31, and the first switching section 40 is the flow rate of the supply path 31 installed on the cooling section 10 side of the connection section of the bypass path 42. It may be composed of an adjustment valve and a flow rate adjustment valve installed in the bypass path 42.

In this case, for example, the supply of the cooling medium to the cooling unit 10 is not completely stopped during the time t1 to t2 in FIG. 2, and a small amount of the cooling medium (supplied to the cooling unit 10 during the time t2 to t3) is supplied. A cooling medium in an amount smaller than the amount) may be supplied to the cooling unit 10. This also applies between the times t1 to t2 and between the times t3 and t4 in FIG. Further, a small amount of cooling medium may flow into the bypass path 42 during the time t2 to t3 in FIG. Further, a small amount of cooling medium may flow into the bypass path 42 during the time t2 to t3 in FIG.

Further, the flow rate of the cooling medium may be adjusted by the first switching unit 40 during the power cycle test in the superimpose test of FIGS. 8 and 12. For example, a small amount of cooling medium may flow into the bypass path 42 by adjusting the valve opening degree of the first switching unit 40 during the times t1 to t2 of FIGS. 8 and 12. Further, during the power cycle test in the superimpose test, the flow rate of the cooling medium may be adjusted by the first switching unit 40 in accordance with the timing of applying the current to the test body 100. For example, during the time t1 to t2 of FIGS. 8 and 12, when the current application to the test piece 100 is turned on, a small amount of the cooling medium is supplied to the cooling unit 10 and the remaining cooling medium flows into the bypass path 42. As such, the valve opening degree of the first switching unit 40 may be adjusted. On the other hand, when the current application to the test piece 100 is turned off, the valve opening degree of the first switching unit 40 is adjusted so that a small amount of the cooling medium flows into the bypass path 42 and the remaining cooling medium is supplied to the cooling unit 10. It may be adjusted.

In the fourth embodiment, the case where the cooling medium in the cooling unit 10 is discharged when the temperature in the chamber 80 becomes equal to or lower than the temperature of the cooling medium has been described, but the temperature in the chamber 80 is equal to or higher than the temperature of the cooling medium. At some point, the cooling medium in the cooling unit 10 may be discharged. Specifically, at the end of the power cycle test (time t2 in the example of FIG. 8), after the temperature in the chamber 80 reaches the upper limit temperature, and before the temperature of the cooling medium becomes lower than the temperature of the cooling medium (time t2 in FIG. 8). The cooling medium in the cooling unit 10 may be discharged (between ~ t3).

Not limited to the case where compressed air is supplied from the gas supply source 53 into the cooling unit 10 via the branch path 51 and the second supply path 31B, the branch path 51 directly communicates with the flow path 11 in the cooling unit 10. You may.

A plurality of circulation circuits 30 may be connected to one cooling medium temperature control unit 20, and the cooling medium may be supplied from the one cooling medium temperature control unit 20 to the plurality of cooling units 10.

It should be understood that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Power cycle test equipment 10 Cooling unit 20 Cooling medium temperature control unit 30 Circulation circuit 40 First switching unit (switching unit)
42 Bypass path 50 Discharge mechanism 53 Gas supply source 60 Current application unit 71 Current application control unit 72 First switching control unit 74 Discharge control unit 77 Storage unit 78 Judgment unit 80 Chamber 100 Specimen I Current

Claims (11)

A current application part that applies a current to the test piece, and
A cooling medium temperature control section for controlling the temperature of the cooling medium for cooling the test piece, and
A cooling unit that cools the test piece with the cooling medium that has been temperature-controlled by the cooling medium temperature control unit,
A circulation circuit that circulates the cooling medium between the cooling medium temperature control section and the cooling section.
A bypass path connected to the circulation circuit so as to bypass the cooling unit,
A switching unit for switching the inflow state of the cooling medium into the bypass path, and
A current application control unit that controls the current application unit so that a power cycle test is executed by repeatedly applying and stopping the current to the test piece.
A power cycle test apparatus including a switching control unit that controls the switching unit according to a predetermined timing in the power cycle test. In the power cycle test, the switching control unit causes the cooling medium to flow into the bypass path when a current is applied from the current application unit to the test body, and the current application unit transfers the current to the test body. The power cycle test apparatus according to claim 1, wherein the switching unit is controlled so that the cooling medium does not flow into the bypass path when the application of the current is stopped. The power cycle test apparatus according to claim 1 or 2, wherein the switching control unit controls the switching unit based on a measured value of a joint temperature of the test piece. The switching control unit is based on a comparison between the measured value of the joint temperature and the target value of the joint temperature so that the measured value of the joint temperature approaches the target value of the joint temperature. The power cycle test apparatus according to claim 3, wherein the power cycle test apparatus is controlled. The switching control unit controls the switching unit so that the inflow state of the cooling medium into the bypass path is switched at a predetermined timing in the power cycle test.
The power cycle test apparatus according to claim 1 or 2, wherein the timing is predetermined based on a time change of the joint temperature of the test body when a current is applied to the test body. The switching unit has a flow rate of the cooling medium flowing into the bypass path and a flow rate of the cooling medium supplied to the cooling unit among the cooling media flowing out from the cooling medium temperature control unit to the circulation circuit. The power cycle test apparatus according to any one of claims 1 to 5, wherein the ratio is adjustable. The power cycle test apparatus according to any one of claims 1 to 6, further comprising a discharge mechanism for discharging the cooling medium from the inside of the cooling unit. The power cycle test apparatus according to claim 7, wherein the discharge mechanism includes a gas supply source that supplies gas to the inside of the cooling unit. A discharge control unit that controls the discharge mechanism is further provided.
The switching control unit controls the switching unit so that the cooling medium flows into the bypass path after the end timing of the power cycle test.
The power cycle according to claim 7 or 8, wherein the discharge control unit operates the discharge mechanism after the end timing and after the switching unit is switched so that the cooling medium flows into the bypass path. Test equipment. Further provided with a chamber in which the test piece is housed
The power cycle test apparatus according to claim 9, wherein the discharge control unit operates the discharge mechanism after the temperature in the chamber reaches the temperature of the cooling medium. It is a method of executing a power cycle test by repeatedly applying an electric current to a test piece and stopping the current.
A power cycle test method for switching the inflow state of a cooling medium into a cooling unit that cools a test body according to a predetermined timing in the power cycle test.

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