JP7223718B2 - Power cycle test device and power cycle test method - Google Patents

Description

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

Conventionally, as described in Patent Document 1, by repeatedly applying and stopping a current to a test body such as a power semiconductor, a thermal shock is applied to the test body to test the reliability of various devices. A cycle test is known. In this power cycle test, the internal heat generation and cooling of the specimen are repeated by the cycle of applying and stopping the current, and the stress caused by the difference in the coefficient of linear expansion deteriorates the joints in the specimen. Body thermal shock resistance is evaluated.

Patent Literature 1 describes a water-cooled heat sink type power cycle test apparatus. This power cycle test equipment consists of a cooling plate on which a test power device is mounted, a chiller, a circulating water pipe that circulates water temperature-controlled by the chiller between the cooling plate, and an electric current to the test power device. A current source for applying current and a control power device for controlling application and interruption of current to the test power device are provided.

Japanese Patent No. 5731448

In Japanese Patent Laid-Open No. 2002-200011, the junction temperature of the test power device repeatedly rises and falls by repeatedly turning on and off the application of current to the test power device. However, the following situations may occur. For example, the supply of cooling water to the cooling plate even when the current application is turned on, which does not require cooling by cooling water, may slow down the increase in temperature of the junction. 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.

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

A power cycle test apparatus according to one aspect of the present invention includes a current application unit that applies a current to a test object, a cooling medium temperature control unit that regulates the temperature of a cooling medium for cooling the test object, and the cooling medium temperature a cooling unit for cooling the test specimen with the cooling medium temperature-controlled by the control unit; a circulation circuit for circulating the cooling medium between the cooling medium temperature control unit and the cooling unit; and bypassing the cooling unit. a bypass route connected to the circulation circuit so as to allow the cooling medium to flow into the bypass route; a switching unit for switching the flow state of the cooling medium into the bypass route; and a current application control unit that controls the current application unit so that the and a switching control unit that controls the switching unit.

According to this power cycle test apparatus, it is possible to execute a power cycle test by repeatedly applying and stopping a current to a test object, and to control the switching section according to a predetermined timing in the power cycle test. As a result, during the power cycle test, it is possible to appropriately switch the flow state of the cooling medium to the bypass path in accordance with 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, it becomes possible to efficiently perform the power cycle test.

In the power cycle test apparatus, the switching control unit causes the cooling medium to flow into the bypass path and the current application unit to flow into the bypass path when a current is being applied from the current application unit to the test object in the power cycle test. The switching unit may be configured to control the switching unit so that the cooling medium does not flow into the bypass path when application of current from the unit to the test object is stopped.

According to this configuration, it is possible to suppress the cooling water from hindering the junction temperature from rising when current is applied to the specimen.

The above power cycle test apparatus may further include a reception unit that receives data of the junction temperature of the test object, and the switching control unit, based on the value of the junction temperature of the test object received by the reception unit, It may be configured to control the switching unit.

According to this configuration, the junction temperature value of the test object received by the reception unit can be used as an index to appropriately switch the flow state of the cooling medium into the bypass path, so that the junction temperature can be controlled more reliably during the power cycle test. it becomes possible to

In the above power cycle test apparatus, the switching control unit determines whether the junction temperature value of the test piece is equal to the target value of the junction temperature of the test piece based on the comparison between the received value of the junction temperature of the test piece and the target value of the junction temperature of the test piece. It may be configured to control the switching unit so as to approach the target value.

According to this configuration, it is possible to appropriately switch the inflow state of the cooling medium to the bypass path based on the difference between the received value of the junction temperature of the test object and its target value. The junction temperature can be reliably controlled by the target value.

The above power cycle test apparatus may further include a reception unit that receives data of the junction temperature of the test piece, and the switching control unit switches to the bypass path at a predetermined timing in the power cycle test. The switching unit may be controlled to switch the inflow state of the cooling medium. The timing may be determined in advance based on a temporal change in junction temperature of the test piece when current is applied to the test piece.

According to this configuration, the inflow state of the cooling medium to the bypass path can be switched at an appropriate timing during the power cycle test without executing arithmetic processing or the like for comparing the measured value of the junction temperature and its target value. can be done.

In the above power cycle test apparatus, the switching unit controls the flow rate of the cooling medium flowing into the bypass path, out of the cooling medium flowing out from the cooling medium temperature control unit to the circulation circuit, and the amount of the cooling medium supplied to the cooling unit. A ratio with the flow rate of the cooling medium may be configured to be adjustable.

With this configuration, the amount of cooling medium flowing into the bypass path can be adjusted more finely, so the junction 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 inside the cooling unit.

According to this configuration, the cooling medium can be discharged from the inside of the cooling section when cooling of the specimen by the cooling medium is unnecessary, and the remaining of the cooling medium in the cooling section can be suppressed.

In the power cycle test apparatus described above, the discharge mechanism may include a gas supply source that supplies gas to the interior of the cooling section.

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

The power cycle test apparatus may further include an ejection control section that controls the ejection mechanism. The switching control section may be configured to control the switching section so that the cooling medium flows into the bypass path after the timing of ending the power cycle test. The discharge control section may be configured to operate the discharge mechanism after the switching section is switched such 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 cooling medium can be stopped from flowing into the cooling section and the cooling medium remaining in the cooling section can be discharged, thereby suppressing the cooling medium from remaining in the cooling section.

The power cycle test apparatus may further include a chamber in which the test specimen is accommodated. The discharge control unit may operate the discharge mechanism after the temperature inside the chamber reaches the temperature of the cooling medium.

According to this configuration, when a thermal cycle test in which the temperature in the chamber is periodically changed is performed in synchronization with the power cycle test, the cooling medium remaining in the cooling unit becomes a heat load, and the test specimen is subjected to the thermal cycle. Inhibition of temperature control can be suppressed.

A power cycle test method according to another aspect of the present invention is a method of executing a power cycle test by repeatedly applying and stopping a current to a test object. In this method, a cooling medium is circulated in a circulation circuit between a cooling medium temperature control unit that controls the temperature of a cooling medium for cooling the test object and a cooling unit that cools the test object, and the power cycle test is performed. A state in which the test body is thermally connected to the cooling unit so that the cooling medium flows through a bypass route connected to the circulation circuit so as to bypass the cooling unit according to a predetermined timing in is maintained, switching the inflow state of the cooling medium to the cooling unit.

According to this method, during the power cycle test, it is possible to appropriately switch the flow state of the cooling medium to the cooling section in accordance with the timing of necessity of supplying the cooling medium to the cooling section. Therefore, according to the power cycle test method of the present invention, it becomes possible to efficiently perform the power cycle test.

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.

1 is a diagram schematically showing the configuration of a power cycle test apparatus according to Embodiment 1 of the present invention; FIG. 4 is a timing chart for explaining the power cycle test method according to Embodiment 1 of the present invention; 4 is a flowchart for explaining a power cycle test method according to Embodiment 1 of the present invention; FIG. 4 is a schematic diagram showing the flow of a cooling medium during current application in the power cycle test method according to Embodiment 1 of the present invention. FIG. 7 is a block diagram for explaining the configuration of a control section in the power cycle test device according to Embodiment 2 of the present invention; FIG. 9 is a timing chart for explaining a power cycle test method according to Embodiment 2 of the present invention; FIG. It is a figure which shows typically the structure of the power-cycle test apparatus which concerns on Embodiment 4 of this invention. FIG. 11 is a timing chart for explaining a superimpose test in Embodiment 4 of the present invention; FIG. FIG. 11 is a schematic diagram for explaining flows of a cooling medium and compressed air in a power cycle test apparatus according to Embodiment 4 of the present invention; FIG. 10 is a diagram schematically showing the configuration of a power cycle test device according to another embodiment of the present invention; FIG. 10 is a diagram schematically showing the configuration of a power cycle test device according to another embodiment of the present invention; 9 is a timing chart for explaining a superimpose test in another embodiment of the invention;

A power cycle test apparatus and a power cycle test method according to embodiments of the present invention will be described in detail below with reference to the drawings.

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

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

The current applying section 60 is a power supply that applies a current I to the test piece 100 . A controller 70 controls the timing of current application from the current applying unit 60 to the test object 100 and the magnitude of the applied current.

The cooling medium temperature control unit 20 controls the temperature of the cooling medium for cooling the specimen 100 during the power cycle test, and is configured by a chiller. The cooling medium is, for example, water (cooling water), but is not limited to this. As shown in FIG. 1, the housing of the cooling medium temperature control unit 20 is provided with a cooling medium inlet 22 and a cooling medium outlet 21 . A refrigerator for cooling the cooling medium, a heater for heating the cooling medium, and a liquid feed pump for sending out the temperature-controlled cooling medium are installed in the housing. The cooling medium temperature control unit 20 in the present embodiment always operates the refrigerator at a constant output and adjusts the temperature of the cooling medium by the output of the heater, but is not limited to this.

The cooling unit 10 is a water-cooled heat sink that cools the specimen 100 with a 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 specimen 100 while the current application is stopped. The cooling part 10 is a plate made of a metal material having a high thermal conductivity, has a mounting surface 10A on which the specimen 100 is mounted, and has a channel 11 through which a cooling medium flows. The test object 100 is cooled by heat radiation from the test object 100 to the cooling medium flowing inside the cooling unit 10 . As shown in FIG. 1 , the cooling unit 10 is provided with a cooling medium inlet 12 and a cooling medium outlet 13 .

The circulation circuit 30 is for circulating the cooling medium between the cooling medium temperature control section 20 and the cooling section 10 . As shown in FIG. 1 , the circulation circuit 30 includes a supply path 31 connecting an outlet 21 of the cooling medium temperature control unit 20 and an inlet 12 of the cooling unit 10 , an inlet 22 of the cooling medium temperature control unit 20 and the cooling unit 10 . and a return path 32 connecting with the outlet 13 of the . The supply path 31 and the return path 32 are configured by pipes in which a flow path through which a 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 configured by a pipe having a flow path formed therein for the cooling medium to flow. The first switching unit 40 is a three-way valve (channel 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 includes a first supply path 31A on the upstream side of the first switching section 40 (the cooling medium temperature control section 20 side) and a downstream side of the first switching section 40 (the cooling section 10 side). side) and the second supply path 31B. The first switching unit 40 is provided with three ports (an inlet port 40A, a first outlet port 40B and a second outlet 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 section 40 and the downstream end of the second supply path 31B is connected to the inlet 12 of the cooling section 10 . Also, the upstream end of the bypass path 42 is connected to the second outlet port 40C of the first switching section 40 .

The first switching unit 40 is controlled by the controller 70 to switch between a supply state in which the inlet port 40A and the first outlet port 40B communicate and a bypass state in which the inlet port 40A and the second outlet port 40C communicate. switch between. In the supply state, the cooling medium flowing out from the outlet 21 of the cooling medium temperature control unit 20 flows from the first supply path 31A through the first switching unit 40 into the second supply path 31B. do 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 unit 20 flows from the first supply path 31A through the first switching unit 40 into the bypass path 42, but the second supply path 31B does not flow into That is, in the bypass state, the cooling medium that has flowed 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 section 41 is a three-way valve configured similarly to the first switching section 40 and is installed in the return path 32 . The return path 32 includes a first return path 32A upstream of the second switching section 41 (cooling section 10 side) and a second return path 32A downstream of the second switching section 41 (cooling medium temperature control section 20 side). and path 32B.

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

The discharge mechanism 50 is for discharging the cooling medium from the inside of the cooling unit 10 (flow path 11). As shown in FIG. 1, the discharge mechanism 50 in this embodiment includes a branch path 51 branching from the second supply path 31B, an opening/closing valve 52 for opening and closing the flow path in the branch path 51, and a first outlet of the branch path 51. 2 gas supply source 53 provided at the end connected to supply path 31B and the opposite end. 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 inside the cooling unit 10 is pushed out by the compressed air and discharged to the outside of the cooling unit 10 . In addition, the gas sent into the cooling part 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. 23.

The reservoir tank 43 is for storing the cooling medium discharged from the cooling section 10 by the discharge mechanism 50 . The reservoir tank 43 is, for example, an open tank and is installed in the recovery path 44 . Note that 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 switch between a return state in which the inlet port 41A and the first outlet port 41B communicate and a recovery state in which the inlet port 41A and the second outlet port 41C communicate. switch between. In the return state, the cooling medium flowing out of the outlet 13 of the cooling unit 10 flows from the first return path 32A through the second switching unit 41 into the second return path 32B, 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 section 10 flows from the first return path 32A through the second switching section 41 into the recovery path 44, but does not flow into the second return path 32B. do not. That is, when recovering the cooling medium to the reservoir tank 43, the second switching unit 41 switches to the recovering state.

The controller 70 is for controlling various operations of the power cycle test apparatus 1, and includes a current application control section 71, a first switching control section 72, a second switching control section 73, a discharge control section 74, and 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 each executed by the central processing unit (CPU; Central Processing Unit) of the controller 70. It is a function.

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

The first switching control section 72 controls the first switching section 40 according to predetermined timing in the power cycle test. More specifically, in the power cycle test, the first switching control section 72 allows the cooling medium to flow into the bypass path 42 when the current I is being applied from the current applying section 60 to the test object 100 and 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 60 to the test object 100 is stopped. The specific contents of this control will be described below with reference to the timing chart of FIG. 2 and the flow chart of FIG.

<Power cycle test method>
A power cycle test method according to this embodiment, which is performed by the controller 70, will be described. This power cycle test method is performed using the power cycle test apparatus 1 described above, and performs a power cycle test by repeatedly applying and stopping the current I to the specimen 100, and performing a predetermined power cycle test in the power cycle test. and switching the flow state of the cooling medium to the cooling unit 10 (the flow state of the cooling medium to the bypass path 42) in accordance with the timing. Specifically, it is as described below.

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

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

Then, the first switching control unit 72 switches the first switching unit 40 from the supply state (FIG. 1) to the bypass state (FIG. 4) while starting to apply current to the test object 100 (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 through the first supply path 31A, the bypass path 42 and the second return path 32B in order 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 object 100 is being energized, it is possible to prevent the cooling medium from hindering the increase in the junction temperature of the test object 100 .

When the junction temperature reaches or exceeds the first set temperature (time t2 in FIG. 2, YES in step S30 in FIG. 3), the current application control section 71 controls the current application section 60 to stop the current application to the specimen 100. (Step S40 in FIG. 3). Along with this, 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, the heat generation inside the specimen 100 stops, and the junction temperature drops toward the second set temperature (lower than the first set temperature and near normal temperature). At this time, since the first switching unit 40 has been switched to the supply state (FIG. 1), the cooling medium flowing out from the outlet 21 of the cooling medium temperature control unit 20 flows through the first supply path 31A and the second supply path 31B in order. flow into the flow path 11 of the cooling unit 10 . As a result, heat is radiated from the test piece 100 to the cooling medium in the cooling unit 10, and the junction temperature quickly 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 is completed, and the number of test cycles is counted to 1 by the processing in the controller 70. plus one (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 test cycle count reaches the set cycle. When the test cycle count reaches the set cycle (YES in step S80 in 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 performed by repeatedly applying and stopping the current I to the test object 100, and at a predetermined timing in the power cycle test, Accordingly, the first switching unit 40 is switched between the supply state and the bypass state. Specifically, the first switching unit 40 is switched to the bypass state (FIG. 4) when current is applied to the test object 100, and the first switching unit 40 is switched to the supply state (FIG. 4) when the current application to the test object 100 is stopped. 1). As a result, the increase in the junction temperature of the specimen 100 is prevented from being hindered by the cooling medium in the cooling section 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 flow of the cooling medium into the cooling section 10 while continuing the operation of the cooling medium temperature control section 20 even when current is applied to the specimen 100 . Therefore, the load on the cooling medium temperature control unit 20 is less than when the cooling medium temperature control unit 20 is repeatedly operated and stopped in response to ON/OFF of the current application to the test object 100 . Therefore, according to the power cycle test apparatus 1 according to this embodiment, it is possible to efficiently perform the power cycle test of the specimen 100 .

<Modification>
Modifications of the first embodiment include the following modes.

In the first embodiment, the current application to the test piece 100 is stopped when the junction temperature rises to the first set temperature or higher, and the current application to the test piece 100 is stopped when the junction temperature drops to the second set temperature or lower. Current application is resumed, but not limited to this. For example, when the first set time elapses from the start of one cycle of the power cycle test, current application to the test object 100 is stopped and the first switching unit 40 is switched from the bypass state to the supply state. good too. Then, based on the lapse of the second set time (time longer than the first set time) from the start of the power cycle test, the current application to the test object 100 is resumed, and the first switching unit 40 may be switched from the supply state to the bypass state.

(Embodiment 2)
Next, a power cycle test apparatus and a power cycle test method according to Embodiment 2 of the present invention will be described with reference to FIGS. 1, 5 and 6. FIG. The power cycle test apparatus and power cycle test method according to the second embodiment are basically the same as those of the first embodiment, except that the first switching control unit 72 switches the first The difference is that the switching unit 40 is controlled. Only points different from the first embodiment will be described below.

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

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

The receiving 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 piece 100 and the detection signal is transmitted to the reception unit 76 . The temperature detection unit 110 measures the junction temperature of the specimen 100 all the time or at predetermined time intervals.

A target value of the junction temperature of the test piece 100 is stored in the storage unit 77 . This target value periodically changes with the elapsed time (horizontal axis of the graph) during the power cycle test, as indicated by the dashed line in the upper graph of FIG.

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

FIG. 6 shows, for one current application cycle in the power cycle test, the measured value of the junction temperature (Tj temperature) and the time change of the target value (upper graph), the on/off timing of the current application to the test body 100 ( middle graph) and on/off timings of the inflow of the cooling medium into the bypass path 42 (lower graph), respectively. In the upper graph, the measured value of the junction temperature is indicated by a solid line, and the target value of the junction temperature is indicated by a dashed line. As in the first embodiment, the power cycle test is started by current application to the specimen 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, between times t1 and t2, the measured junction temperature is less than its 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 junction temperature rise gradient gradually increases. Then, the measured value of the junction temperature approaches the target value and becomes the same as the target value at time t2 in FIG.

Between times t2 and t3 in FIG. 6, the measured value of the junction temperature is higher than its 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 section 10, and the heat inside the specimen 100 is taken away by the cooling medium, so that the rising gradient of the junction temperature gradually decreases. Then, the measured value of the junction temperature approaches the target value and becomes the same as the target value at time t3 in FIG.

Between times t3 and t4 in FIG. 6, the measured value of the junction temperature is lower than the target value, similarly to between times t1 and t2. Therefore, the first switching control section 72 maintains the first switching section 40 in the bypass state based on the determination result by the determining section 78 (target value>measured value). 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 object 100 as in the first embodiment, when the current is applied to the test object 100 (Fig. 6) also switches the first switching unit 40 between the supply state and the bypass state based on the comparison between the measured value of the junction temperature and its target value.

As described above, in the second embodiment, using the measured value of the junction temperature of the test piece 100 as an index, more specifically, based on the difference between the measured value of the junction temperature and its target value, the first The switching unit 40 is controlled. As a result, the junction temperature can be brought closer to the target temperature more reliably, and the power cycle test can be performed under more appropriate conditions.

(Embodiment 3)
Next, a power cycle test apparatus and a power cycle test method according to Embodiment 3 of the present invention will be described. In the present embodiment, the first switching control section 72 controls the first switching section 40 so that the state of the cooling medium flowing 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 temporal change in the junction temperature of the test piece 100 when current is applied to the test piece 100, and the information is stored in the storage unit 77 (FIG. 5). . That is, the measured value of the junction temperature (the solid line in the upper graph in FIG. 6) and the target value of the junction temperature (the dashed line in the same graph) when current is applied to the test body 100 are compared, and both values match. Timings (times t2 and t3 in FIG. 6) are determined in advance, and the information is stored in the storage unit 77. FIG.

During the power cycle test, the first switching control section 72 controls the first switching section 40 based on the predetermined timing. 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 FIG. . The current value applied to the test object 100 during the power cycle test is the same as the current value applied to the test object 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. This makes it possible to switch the flow state of the cooling medium to the bypass path 42 at an appropriate timing without performing arithmetic processing or the like for comparing the measured value of the junction temperature and its target value.

(Embodiment 4)
Next, a power cycle test apparatus and a power cycle test method according to Embodiment 4 of the present invention will be described with reference to FIGS. 7 and 8. FIG. The power cycle test apparatus and power cycle test method according to Embodiment 4 are basically the same as those in Embodiments 1 to 3 above, but a thermal power cycle tester that periodically changes the temperature in chamber 80 in which test piece 100 is accommodated is used. The difference is that the cycle test is executed in synchronization with the power cycle test. Only points different from the first to third embodiments will be described below.

As shown in FIG. 7, the power cycle test apparatus according to the present embodiment includes a chamber 80 in which a specimen 100 is accommodated, a chamber temperature control section 82 for controlling the temperature of the air in the chamber 80, and a chamber temperature control section 82. and a controller 70B. The chamber temperature control unit 82 includes a heater 83 that heats the air in the chamber 80 and a refrigerator cooler 84 (evaporator) that cools the air. A space in the chamber 80 is partitioned by a partition plate 81 into a test chamber 80A in which the specimen 100 is accommodated and an air-conditioned chamber 80B in which a chamber temperature control section 82 and a blower section 85 are installed. Note that the cooling mechanism for cooling the air in the chamber 80 is not limited to a refrigerator.

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

The power cycle test apparatus according to this embodiment is configured to be able to perform a superimpose test that synchronizes the power cycle test and the thermal cycle test. 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 body 100 (middle graph), and the cooling medium flow to the bypass path 42 in the superimpose test. The inflow on/off timing (bottom graph) is shown. Note that the time period from t1 to t2 in the figure is, for example, 2 minutes or more and 5 minutes or less, but is not limited to this. Moreover, the power cycle test apparatus of the present invention is not limited to synchronizing the power cycle test and the thermal cycle test, and may perform the power cycle test while the temperature inside the chamber 80 is kept constant.

As shown in FIG. 8, the chamber temperature control section 79 controls the chamber temperature control section 82 so that the temperature inside the chamber 80 periodically changes 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 (time t1 in FIG. 8) when the temperature inside the chamber 80 turns upward, and at the timing when the temperature inside the chamber 80 turns downward. The current applying 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 power cycle test ends. Specifically, the first switching unit 40 is maintained in the supply state during the power cycle test (time t1 to t2 in FIG. 8), 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 power cycle test end timing and after the first switching unit 40 is switched so that the cooling medium flows into the bypass path 42 . Specifically, the discharge control unit 74 activates the discharge mechanism 50 after the temperature inside the chamber 80 has turned downward and becomes equal to or lower than the temperature of the cooling medium (time t3 in FIG. 8). (opens the on-off valve 52). At the timing of operating the discharge mechanism 50, the second switching control section 73 switches the second switching section 41 from the return state to the recovery state.

FIG. 9 shows the flow of cooling medium and compressed air in the power cycle test apparatus during times t3 to t4 in FIG. 8, respectively. In the figure, the flow of cooling medium is indicated by dashed arrows, and the flow of compressed air is indicated by solid arrows.

As shown in FIG. 9, between times t3 and t4, the cooling medium flows out from the outlet 21 of the cooling medium temperature control unit 20, and then flows through the first supply path 31A, the bypass path 42, and the second return path 32B in order. The cooling unit 10 is not supplied with the cooling unit 10 because the cooling unit 10 is not supplied. On the other hand, compressed air is sent from the gas supply source 53 into the interior of the cooling unit 10 (the flow path 11) via the branch path 51 and the second supply path 31B.

As a result, the cooling medium remaining in the cooling section 10 is pushed out to the first return path 32A by the compressed air. This cooling medium flows from the first return path 32</b>A into the recovery path 44 and is stored in the reservoir tank 43 . Then, the cooling medium collected in the reservoir tank 43 is returned into the cooling medium temperature control section 20 through the supply port 23 . It should be noted that the compressed air does not necessarily need to be constantly supplied between times t3 and t4 in FIG. good too.

As described above, in this embodiment, in the superimposed test in which the power cycle test and the thermal cycle test are synchronized, after the power cycle test is completed and when the temperature in the chamber 80 is equal to or lower than the temperature of the cooling medium, The discharge mechanism 50 is operated to discharge the cooling medium inside 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 specimen 100 in the thermal cycle test.

(Other embodiments)
Other embodiments of the invention will now 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 inside 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. In addition, the pump 44A may be installed in the first return path 32A.

In the above-described Embodiment 4, the power cycle test is started at the timing when the temperature inside the chamber turns to an upward trend in the superimpose test, and the power cycle test ends at the timing when the temperature inside the chamber turns to a downward trend, but it is limited to this. not. For example, as shown in FIG. 12, in the superimpose test, even if the power cycle test is started at the timing when the temperature inside the chamber turns to a downward trend, and the power cycle test ends at the timing when the temperature inside the chamber turns to an upward trend, good. In this case, the discharge mechanism 50 may be operated after time t2 in FIG. 12 (after the cooling medium starts to flow into the bypass path 42), or after time t3 in FIG. The discharge mechanism 50 may be operated after the temperature of the cooling medium is reached).

In the above-described fourth embodiment, a case has been described in which the first switching unit 40 is switched to the bypass state at the same time as the power cycle test is completed in the superimpose test, but the power cycle test is performed 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 when the power cycle test is completed. 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 execution of the power cycle test in the superimposed test, but the present invention is not limited to this. The switching unit 40 may be put into a bypass state. Also, during execution of the power cycle test, the first switching unit 40 may be switched between the supply state and the bypass state as appropriate in accordance with the timing of current application to the test object 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. 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 determines the flow rate of the cooling medium flowing into the bypass path 42 among the cooling medium flowing out from the cooling medium temperature control unit 20 to the circulation circuit 30 (first supply path 31A) and the flow rate of the cooling medium supplied to the cooling unit 10. The ratio with the flow rate of the cooling medium may be configured to be adjustable. Specifically, the upstream end of the bypass route 42 is connected to the supply route 31 , and the first switching unit 40 is installed on the cooling unit 10 side of the connection part of the bypass route 42 in the supply route 31 . 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. A lesser amount of cooling medium) may be supplied to the cooling unit 10 . This is the same for times t1 to t2 and times t3 to t4 in FIG. Also, a small amount of the cooling medium may flow into the bypass path 42 between times t2 and t3 in FIG. Also, a small amount of the cooling medium may flow into the bypass path 42 between times t2 and t3 in FIG.

Also, the flow rate of the cooling medium may be adjusted by the first switching unit 40 during the power cycle test in the superimposed 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 between times t1 and t2 in FIGS. 8 and 12 . Furthermore, during the power cycle test in the superimpose test, the first switching unit 40 may adjust the flow rate of the cooling medium in accordance with the timing of current application to the specimen 100 . For example, between times t1 and t2 in FIGS. 8 and 12, when the current application to the specimen 100 is turned on, a small amount of cooling medium is supplied to the cooling unit 10 and the remaining cooling medium flows into the bypass path 42. The valve opening degree of the first switching unit 40 may be adjusted so as to do so. On the other hand, when the current application to the specimen 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. may be adjusted.

In the above-described 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. The cooling medium in the cooling unit 10 may be discharged at certain times. 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 drops below (time t2 in FIG. 8). to t3), the cooling medium in the cooling unit 10 may be discharged.

The supply of compressed air from the gas supply source 53 to the cooling unit 10 via the branch path 51 and the second supply path 31B is not limited, and the branch path 51 directly communicates with the flow path 11 in the cooling unit 10. 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 single cooling medium temperature control unit 20 to the plurality of cooling units 10 .

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

1 power cycle test device 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 determination unit 80 chamber 100 specimen I current

Claims (11)

a current applying unit that applies a current to the test object;
a cooling medium temperature control unit for controlling the temperature of a cooling medium for cooling the test specimen;
a cooling unit for cooling the test body with the cooling medium temperature-controlled by the cooling medium temperature control unit;
a circulation circuit for circulating the cooling medium between the cooling medium temperature control section and the cooling section;
a bypass route connected to the circulation circuit so as to bypass the cooling unit;
a switching unit for switching an inflow state of the cooling medium to the bypass path;
a current application control unit that controls the current application unit to perform a power cycle test by repeatedly applying and stopping the current to the test object;
A power cycle test apparatus comprising: a switching control unit that controls the switching unit according to a predetermined timing in the power cycle test while maintaining the state in which the test object is thermally connected to the cooling unit. In the power cycle test, the switching control unit causes the cooling medium to flow into the bypass path and flow from the current application unit to the test object when a current is being applied from the current application unit to the test object. 2. The power cycle test apparatus according to claim 1, wherein said switching unit is controlled so that said cooling medium does not flow into said bypass path when application of current is stopped. Further comprising a reception unit for receiving data of the junction temperature of the test body,
3. The power cycle test apparatus according to claim 1, wherein said switching control section controls said switching section based on the value of the junction temperature of said test object received by said receiving section . The switching control unit causes the value of the junction temperature of the test object to approach the target value based on the comparison between the received value of the junction temperature of the test object and the target value of the junction temperature of the test object. 4. The power cycle test apparatus according to claim 3, wherein said switching unit is controlled so as to Further comprising a reception unit for receiving data of the junction temperature of the test body,
The switching control unit controls the switching unit so as to switch the inflow state of the cooling medium to the bypass path at a predetermined timing in the power cycle test,
3. The power cycle test apparatus according to claim 1, wherein said timing is determined in advance based on a temporal change in junction temperature of said test object when current is applied to said test object. The switching unit controls the flow rate of the cooling medium that flows into the bypass path and the flow rate of the cooling medium that is supplied to the cooling unit, among the cooling medium that has flowed 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 said cooling medium from inside said cooling section. 8. The power cycle test apparatus according to claim 7, wherein said exhaust mechanism includes a gas supply source that supplies gas to the interior of said cooling unit. further comprising an ejection control unit that controls the ejection mechanism,
The switching control unit controls the switching unit so that the cooling medium flows into the bypass path after the timing at which the power cycle test ends,
9. The power cycle according to claim 7, wherein the discharge control unit operates the discharge mechanism after the end timing and after the switching unit switches such that the cooling medium flows into the bypass path. test equipment. Further comprising a chamber in which the test body is accommodated,
10. The power cycle test apparatus according to claim 9, wherein the timing at which said discharge control unit operates said discharge mechanism is after the temperature in said chamber reaches the temperature of said cooling medium. A method for performing a power cycle test by repeatedly applying and stopping a current to a test object,
circulating a cooling medium in a circulation circuit between a cooling medium temperature control unit for controlling the temperature of a cooling medium for cooling a test object and a cooling unit for cooling the test object;
According to a predetermined timing in the power cycle test, the test body is thermally transferred to the cooling unit so that the cooling medium flows through a bypass route connected to the circulation circuit so as to bypass the cooling unit. A power cycle test method for switching the inflow state of the cooling medium to the cooling unit while maintaining the connected state .

Images