A power device testing method and apparatus

Abstract

The application discloses a kind of power device test method and device.Power device test method is realized by power device testing device, and testing device includes bridge circuit and inductive load, bridge circuit includes multiple switches, and the power device to be measured is as a switch in bridge circuit;Test method includes: control bridge circuit to inductive load charges and discharges, and adjust the discharge duration or charge duration of inductive load in each charge and discharge cycle, to make the turn-on current of the power device to be measured gradually reach preset current, and maintain turn-on current as preset current;According to the turn-on current of the power device to be measured in each charge and discharge cycle and the turn-on voltage of the power device to be measured, determine the resistance of the power device to be measured in each charge and discharge cycle, to test the dynamic resistance of the power device to be measured.The technical scheme of the application is convenient for accurately adjusting the turn-on current of the power device to be measured, and is conducive to improving the accuracy of dynamic test of the power device to be measured.

Description

Technical Field

[0001] This invention relates to the field of power device testing technology, and in particular to a power device testing method and apparatus. Background Technology

[0002] Gallium nitride power devices, with their low on-resistance, low parasitic capacitance, and zero reverse recovery charge, have become one of the best candidates for next-generation high-frequency, high-efficiency, and high-power-density converters.

[0003] Gallium nitride (GaN) power devices are prone to dynamic resistance degradation during use. Therefore, dynamic resistance testing and aging testing are required for GaN power devices to ensure better application of GaN power devices.

[0004] However, in existing gallium nitride power device test circuits, changing the input voltage causes a change in the turn-on current of the device under test, making it inconvenient to adjust the input voltage and turn-on current, and also resulting in high power consumption. Summary of the Invention

[0005] This invention provides a power device testing method and apparatus to solve the problems of inconvenient adjustment of input voltage and turn-on current and high power consumption when testing power devices.

[0006] According to one aspect of the present invention, a power device testing method is provided, the testing method being implemented by a power device testing device, the testing device including a bridge circuit and an inductive load, the bridge circuit including a plurality of switches, the power device under test being one of the switches in the bridge circuit;

[0007] The testing method includes:

[0008] The bridge circuit is controlled to charge and discharge the inductive load, and the discharge duration or charging duration of the inductive load in each charge and discharge cycle is adjusted so that the turn-on current of the power device under test gradually reaches the preset current and the turn-on current is maintained at the preset current.

[0009] Based on the turn-on current and turn-on voltage of the power device under test in each charge-discharge cycle, the resistance value of the power device under test in each charge-discharge cycle is determined to test the dynamic resistance of the power device under test.

[0010] Optionally, controlling the bridge circuit to charge and discharge the inductive load, and adjusting the discharge duration of the inductive load in each charge and discharge cycle, so that the turn-on current of the power device under test gradually reaches the preset current, and maintaining the turn-on current at the preset current, includes:

[0011] The bridge circuit is controlled to charge the inductive load for a first preset duration.

[0012] The discharge duration of the inductive load in each charge-discharge cycle is adjusted, and the bridge circuit is controlled to discharge the inductive load according to the adjusted discharge duration; wherein, the discharge duration of the inductive load is not exactly the same as the charging duration of the inductive load; the discharge duration of the inductive load is not exactly the same in different charge-discharge cycles.

[0013] Optionally, the bridge circuit includes a first bridge arm circuit, a second bridge arm circuit, a third bridge arm circuit, and a fourth bridge arm circuit. The first bridge arm circuit is electrically connected to the second bridge arm circuit, and the third bridge arm circuit is electrically connected to the fourth bridge arm circuit. Each bridge arm circuit includes one of the switches. The power device under test is located in the second bridge arm circuit or the fourth bridge arm circuit.

[0014] The control of the bridge circuit to charge the inductive load for a first preset duration includes:

[0015] The first bridge arm circuit and the fourth bridge arm circuit are controlled to conduct for the first preset duration so as to charge the inductive load according to the first preset duration;

[0016] And / or, adjusting the discharge duration of the inductive load in each charge-discharge cycle, and controlling the bridge circuit to discharge the inductive load according to the adjusted discharge duration, including:

[0017] Control the second bridge arm circuit and the third bridge arm circuit to conduct;

[0018] The first bridge arm circuit and the third bridge arm circuit are controlled to be turned on, and the on-time of the first bridge arm circuit is adjusted to adjust the freewheeling start time so that the discharge time of the inductive load is the adjusted discharge time; wherein, when the first bridge arm circuit is turned on, the second bridge arm circuit is turned off; when the first bridge arm circuit is turned off, the second bridge arm circuit is turned on.

[0019] Optionally, the bridge circuit includes a first bridge arm circuit, a second bridge arm circuit, a third bridge arm circuit, and a fourth bridge arm circuit. The first bridge arm circuit is electrically connected to the second bridge arm circuit, and the third bridge arm circuit is electrically connected to the fourth bridge arm circuit. Each bridge arm circuit includes one of the switches. The power device under test is located in the second bridge arm circuit or the fourth bridge arm circuit.

[0020] The step of controlling the bridge circuit to charge and discharge the inductive load, and adjusting the discharge duration or charging duration of the inductive load in each charge-discharge cycle, so that the turn-on current of the power device under test gradually reaches the preset current, and maintaining the turn-on current at the preset current, includes:

[0021] The first bridge arm circuit and the fourth bridge arm circuit are controlled to be turned on, and the on-time of the first bridge arm circuit is adjusted to adjust the on-time of the second bridge arm circuit; so that the charging time of the inductive load is either the adjusted charging time or the unadjusted charging time; wherein, in different charge and discharge cycles, the start time of the first bridge arm circuit and the fourth bridge arm circuit being turned on is the same, but the end time is not exactly the same; when the first bridge arm circuit is turned on, the second bridge arm circuit is turned off; when the first bridge arm circuit is turned off, the second bridge arm circuit is turned on.

[0022] The second bridge arm circuit and the third bridge arm circuit are controlled to be turned on so that the discharge duration of the inductive load is either the adjusted discharge duration or the unadjusted discharge duration.

[0023] Optionally, adjusting the conduction duration of the first bridge arm circuit to adjust the freewheeling start time includes:

[0024] Increase the conduction time of the first bridge arm circuit so that the adjusted discharge time is less than the charging time of the inductive load.

[0025] Optionally, before controlling the bridge circuit to discharge the inductive load according to the adjusted discharge duration, the method further includes:

[0026] The second bridge arm circuit and the fourth bridge arm circuit are turned on, or the first bridge arm circuit and the third bridge arm circuit are turned on, or the first bridge arm circuit, the second bridge arm circuit, the third bridge arm circuit and the fourth bridge arm circuit are turned off, so as to provide freewheeling current for the inductive load.

[0027] Optionally, adjusting the discharge duration or charging duration of the inductive load in each charge-discharge cycle includes:

[0028] The discharge duration or charging duration of the inductive load in each charge-discharge cycle is adjusted according to the closed-loop control strategy and the preset current; wherein, the closed-loop control strategy includes a proportional-integral-derivative control strategy or a proportional-integral control strategy.

[0029] According to another aspect of the present invention, a power device testing apparatus is provided, comprising a bridge circuit, an inductive load, and a control module; the control module is used to execute the power device testing method according to any embodiment of the present invention; the bridge circuit is connected to the inductive load;

[0030] The control module is connected to the bridge circuit. The control module is used to control the bridge circuit to charge and discharge the inductive load, and to adjust the discharge duration or charging duration of the inductive load in each charge and discharge cycle, so that the turn-on current of the power device under test gradually reaches the preset current and maintains the turn-on current at the preset current. Based on the turn-on current and turn-on voltage of the power device under test in each charge and discharge cycle, the control module determines the resistance value of the power device under test in each charge and discharge cycle, so as to test the dynamic resistance of the power device under test.

[0031] Optionally, the bridge circuit includes:

[0032] The circuit comprises a first bridge arm circuit, a second bridge arm circuit, a third bridge arm circuit, and a fourth bridge arm circuit, each bridge arm circuit including one of the aforementioned switches; the power device under test is located in the second bridge arm circuit or the fourth bridge arm circuit.

[0033] The first end of the first bridge arm circuit is connected to the first power supply; the first end of the second bridge arm circuit is electrically connected to the second end of the first bridge arm circuit, and the second end of the second bridge arm circuit is connected to the second power supply.

[0034] The first end of the third bridge arm circuit is connected to the first power supply; the first end of the fourth bridge arm circuit is electrically connected to the second end of the third bridge arm circuit, and the second end of the fourth bridge arm circuit is connected to the second power supply.

[0035] The inductive load is connected between the second end of the first bridge arm circuit and the second end of the third bridge arm circuit.

[0036] Optionally, the testing apparatus further includes a test resistor;

[0037] The test resistor is connected between the second terminal of the second bridge arm circuit and the second terminal of the fourth bridge arm circuit.

[0038] The control module is connected to the test resistor, and the control module is also used to obtain the turn-on current of the power device under test through the test resistor.

[0039] The technical solution of this invention adjusts the current of the inductive load at the end of each charge / discharge cycle by regulating the discharge or charging duration of the inductive load. This allows for the regulation of the inductive load current, enabling it to gradually reach and stabilize at a preset current. Consequently, it regulates the turn-on current of the power device under test (DUT), maintaining it at the preset current. Therefore, by simply setting a preset current, the test method of this embodiment can achieve a turn-on current close to or equal to the preset current, facilitating accurate adjustment of the DUT's turn-on current. Furthermore, even when the input voltage changes, since the preset current remains unchanged, the test method of this embodiment still adjusts the DUT's turn-on current with the preset current as the target. Therefore, changes in input voltage do not affect changes in the turn-on current, allowing for convenient and accurate adjustment of both the input voltage and the turn-on current, facilitating accurate testing of the dynamic characteristics of the DUT. Moreover, by setting up a bridge circuit, when the inductive load is discharged, the energy of the inductive load can be fed back to the input power supply through the bridge circuit, so that there is basically no loss during the entire test process, thereby effectively reducing power consumption.

[0040] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a test circuit diagram for a gallium nitride power device in the prior art;

[0043] Figure 2 This is another test circuit diagram for gallium nitride power devices in the prior art;

[0044] Figure 3 This is another test circuit diagram for gallium nitride power devices in the prior art;

[0045] Figure 4 This is another test circuit diagram for gallium nitride power devices in the prior art;

[0046] Figure 5 This is another test circuit diagram for gallium nitride power devices in the prior art;

[0047] Figure 6 This is a flowchart of a power device testing method provided in an embodiment of the present invention;

[0048] Figure 7 This is a flowchart of another power device testing method provided in an embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram of a bridge circuit provided in an embodiment of the present invention;

[0050] Figure 9 This is a driving timing diagram provided in an embodiment of the present invention;

[0051] Figure 10 This is a flowchart of another power device testing method provided in an embodiment of the present invention;

[0052] Figure 11 This is a current curve diagram of an inductive load provided in an embodiment of the present invention;

[0053] Figure 12 This is yet another driving timing diagram provided in the embodiments of the present invention;

[0054] Figure 13 This is a flowchart of another power device testing method provided in an embodiment of the present invention;

[0055] Figure 14 This is a schematic diagram of the structure of a power device testing device provided in an embodiment of the present invention;

[0056] Figure 15 This is a schematic diagram of another power device testing device provided in an embodiment of the present invention. Detailed Implementation

[0057] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0058] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0059] Power devices include, for example, gallium nitride (GaN) power devices. To better utilize GaN power devices, it is necessary to detect their dynamic characteristics during use. Figure 1 This is a test circuit diagram for a gallium nitride power device in the prior art, such as... Figure 1 As shown, the aging test of the device under test (DUT) is achieved by charging and discharging the first load resistor R01 and the first load capacitor C01. At the moment the DUT is turned on, the input voltage charges the first load capacitor C01 through the DUT. The turn-on current of the DUT is adjusted by changing the capacitance of the first load capacitor C01 or the switching speed, thereby simulating different operating environments of the DUT and testing it. However, when adjusting the input voltage Vdd, the change in input voltage leads to a change in the turn-on current, so the capacitance of the first load capacitor C01 also needs to be changed, making voltage and current adjustment inconvenient.

[0060] Figure 2 This is another test circuit diagram for gallium nitride power devices in the prior art, such as... Figure 2 As shown, the device under test (DUT) is turned on by a driver board. At the instant the DUT is turned on, current is commutated from the first load inductor L01 to the DUT. The turn-on current is adjusted by changing the inductance of the first load inductor L01 and the resistance of the second load resistor R02. Changing the input voltage will cause the turn-on current to change, so the inductance of the first load inductor L01 must be changed simultaneously, making voltage and current adjustment inconvenient.

[0061] Figure 3 This is another test circuit diagram for gallium nitride power devices in the prior art, such as... Figure 3 As shown, the first input voltage Vdd1 controls the turn-on and turn-off of the device under test (DUT), while the second input voltage Vdd2 provides current to the DUT. The magnitude and rise rate of the turn-on current of the DUT are determined by the third load resistor R03, and the presence of the third load resistor R03 results in relatively high power consumption of the entire device.

[0062] Figure 4 This is another test circuit diagram for gallium nitride power devices in the prior art, such as... Figure 4 As shown, when a high-level voltage is input to the gate of the device under test (DUT), the DUT is turned on. At the instant the DUT is turned on, the current slowly rises from zero to charge the second load inductor L02. The magnitude and rate of rise of the current are determined by the inductance value of the second load inductor L02. After the DUT is turned off, the second load inductor L02 freewheels through diode D1. The energy stored in the second load inductor L02 needs to be released during the device's turn-off period. Changes in the input voltage Vdd will cause changes in the turn-on current, so the inductance value of the second load inductor L02 needs to be changed simultaneously, leading to inconvenience in voltage and current regulation.

[0063] Figure 5 This is another test circuit diagram for gallium nitride power devices in the prior art, such as... Figure 5 As shown, an aging test is performed on the device under test (DUT) based on a Boost circuit. The turn-on current of the DUT is determined by the resistance value of the fourth load resistor R04. Changes in the input voltage Vdd will cause changes in the turn-on current, so the resistance value of the fourth load resistor R04 needs to be changed simultaneously, leading to inconvenience in voltage and current adjustment.

[0064] In summary, existing gallium nitride power device test circuits cause changes in the turn-on current of the device under test when the input voltage is changed, resulting in inconvenience in adjusting the input voltage and turn-on current, as well as significant power consumption.

[0065] To address the aforementioned technical problems, this embodiment provides a power device testing method. The testing method is implemented using a power device testing device, which includes a bridge circuit and an inductive load. The bridge circuit includes multiple switches, with the power device under test serving as one of the switches in the bridge circuit. The power device under test can be a gallium nitride (GaN) power device or other types of power devices. The bridge circuit can include a half-bridge circuit, a full-bridge circuit, or a three-phase bridge circuit, etc. The inductive load is a load with inductive parameters and can include inductors, etc. The power device under test, acting as a switch in the bridge circuit, allows the inductive load to be charged and discharged, thereby recreating the usage conditions of the power device under test and testing its characteristics (e.g., dynamic resistance) during long-term use.

[0066] Figure 6 This is a flowchart of a power device testing method provided in an embodiment of the present invention, such as... Figure 6 As shown, the method includes:

[0067] S110: Control the bridge circuit to charge and discharge the inductive load, and adjust the discharge duration or charging duration of the inductive load in each charge and discharge cycle so that the turn-on current of the power device under test gradually reaches the preset current and maintains the turn-on current at the preset current.

[0068] The bridge circuit is connected to the power supply voltage. By controlling the conduction state of the bridge circuit, the power supply voltage can charge and discharge the inductive load through the bridge circuit. In order to test the dynamic characteristics of the power device under test during long-term use, the inductive load needs to be charged and discharged multiple times. For example, each complete charge and discharge cycle is one charge and discharge cycle.

[0069] Specifically, by adjusting the discharge or charging duration of the inductive load in each charge-discharge cycle, the current of the inductive load at the end of each charge-discharge cycle can be adjusted. For example, if the charging duration remains constant, and the discharge duration is equal to the charging duration, the current of the inductive load is completely released at the end of this charge-discharge cycle, making the current of the inductive load consistent with the current before the start of this charge-discharge cycle. When the discharge duration is longer than the charging duration, the current of the inductive load at the end of this charge-discharge cycle is less than the current before the start of this charge-discharge cycle. When the discharge duration is shorter than the charging duration, the current of the inductive load at the end of this charge-discharge cycle is greater than the current before the start of this charge-discharge cycle. In this way, the current of the inductive load can be adjusted, thereby adjusting the turn-on current of the power device under test, so that the turn-on current of the power device under test is maintained at a preset current. Similarly, when the discharge duration remains constant, by reducing the charging duration, the discharge duration can be made longer than the charging duration, and the current of the inductive load at the end of this charge-discharge cycle is less than the current before the start of this charge-discharge cycle. By increasing the charging time, the discharging time can be made shorter than the charging time. At the end of this charge / discharge cycle, the current in the inductive load is greater than the current before the start of the cycle. Therefore, by setting different preset currents, different turn-on currents of the power device under test can be simulated, thereby testing the dynamic characteristics of the power device under test under different operating conditions.

[0070] For example, before charging and discharging the inductive load, the current of the inductive load is zero. By adjusting the discharge duration in each charge-discharge cycle, for example, by continuously decreasing the discharge duration in each charge-discharge cycle, the current of the inductive load is continuously increased until the current of the inductive load reaches a preset current, thereby gradually bringing the turn-on current of the power device under test to the preset current. Once the current of the inductive load reaches the preset current, the discharge duration of each charge-discharge cycle can be adjusted according to the actual current of the inductive load. Thus, by adjusting the current of the inductive load after the end of the charge-discharge cycle, the turn-on current of the power device under test can be adjusted. By simply setting a preset current, the test method of this embodiment can achieve a turn-on current close to or equal to the preset current, facilitating accurate adjustment of the turn-on current of the power device under test.

[0071] Furthermore, even when the input voltage changes, since the preset current remains unchanged, the test method in this embodiment will still adjust the turn-on current of the device under test based on the preset current. Therefore, changes in the input voltage will not affect changes in the turn-on current, allowing for convenient and accurate adjustment of both the input voltage and the turn-on current.

[0072] S120. Based on the turn-on current and turn-on voltage of the power device under test in each charge and discharge cycle, determine the resistance value of the power device under test in each charge and discharge cycle, so as to test the dynamic resistance of the power device under test.

[0073] Specifically, the resistance of the power device under test (DUT) can be calculated by measuring its turn-on current and turn-on voltage. Through multiple charge-discharge cycles, the resistance during operation is tested, enabling dynamic resistance testing. Furthermore, the dynamic resistance of the DUT can be tested under different operating conditions by changing the preset current or input voltage. This provides a more comprehensive understanding of the dynamic characteristics of the DUT, facilitating its better application based on these characteristics.

[0074] Furthermore, the technical solution of this embodiment uses a bridge circuit. When the bridge circuit discharges the inductive load, the energy of the inductive load can be fed back to the input power supply through the bridge circuit, so that there is basically no loss during the entire test process, thereby effectively reducing power consumption.

[0075] In summary, the technical solution of this embodiment, by adjusting the discharge or charging duration of the inductive load in each charge-discharge cycle, can regulate the current of the inductive load after each charge-discharge cycle. This allows the current of the inductive load to gradually reach and stabilize at a preset current, thereby regulating the turn-on current of the power device under test (DUT) and maintaining it at the preset current. Therefore, by simply setting a preset current, the test method of this embodiment can achieve a turn-on current close to or equal to the preset current, facilitating accurate adjustment of the turn-on current of the DUT. Furthermore, even when the input voltage changes, since the preset current remains unchanged, the test method of this embodiment will still adjust the turn-on current of the DUT based on the preset current. Therefore, changes in input voltage do not affect changes in the turn-on current, allowing for convenient and accurate adjustment of both input voltage and turn-on current, facilitating accurate testing of the dynamic characteristics of the DUT. Moreover, by setting up a bridge circuit, when the inductive load is discharged, the energy of the inductive load can be fed back to the input power supply through the bridge circuit, so that there is basically no loss during the entire test process, thereby effectively reducing power consumption.

[0076] It should be noted that in some other implementations, both the charging time and the discharging time can be adjusted, for example, by increasing the charging time and decreasing the discharging time, or by decreasing the charging time and increasing the discharging time, thereby adjusting the turn-on current of the power device under test.

[0077] Based on the above technical solution, the following further explains the process of controlling the bridge circuit to charge and discharge inductive loads and the adjustment of the discharge duration, but this is not intended to limit this application.

[0078] Figure 7 This is a flowchart of another power device testing method provided in an embodiment of the present invention. Optionally, refer to... Figure 7 Power device testing methods include:

[0079] S210, Control the bridge circuit to charge the inductive load for a first preset duration.

[0080] Specifically, the first preset duration can be determined based on the preset current. For example, if the preset current is large, the first preset duration can be set to be large. The first preset duration can also be preset in advance. By controlling the bridge circuit to charge the inductive load according to the first preset duration, it is convenient to restore the operating condition of the power device under test when in use, and to perform dynamic testing on the power device under test.

[0081] S220: Adjust the discharge duration of the inductive load in each charge-discharge cycle, and control the bridge circuit to discharge the inductive load according to the adjusted discharge duration.

[0082] The discharge duration of an inductive load is not exactly the same as its charging duration; the discharge duration of an inductive load is not exactly the same in different charge / discharge cycles. In other words, the discharge duration of an inductive load may be the same or different in different charge / discharge cycles. Within each charge / discharge cycle, the charging duration and discharge duration of the inductive load may be the same or different.

[0083] For example, if the actual current of the inductive load is close to or equal to the preset current before the start of the current charge / discharge cycle, the discharge duration of the current charge / discharge cycle can be controlled to be equal to the charging duration; if the actual current of the inductive load is less than the preset current before the start of the current charge / discharge cycle, the discharge duration of the current charge / discharge cycle can be controlled to be greater than the charging duration; if the actual current of the inductive load is greater than the preset current before the start of the current charge / discharge cycle, the discharge duration of the current charge / discharge cycle can be controlled to be less than the charging duration. Thus, the current of the inductive load after the end of the charge / discharge cycle is adjusted so that the actual current of the inductive load is close to or equal to the preset current, i.e., the on-state current is maintained at the preset current.

[0084] S230. Based on the turn-on current and turn-on voltage of the power device under test in each charge and discharge cycle, determine the resistance value of the power device under test in each charge and discharge cycle, so as to test the dynamic resistance of the power device under test.

[0085] Based on the above technical solutions, the following further explains the charging and discharging process of inductive loads and the adjustment of discharge time in conjunction with the possible structures of bridge circuits, but this is not intended to limit this application.

[0086] Figure 8 This is a schematic diagram of a bridge circuit provided in an embodiment of the present invention. Optionally, refer to... Figure 8 The bridge circuit 10 includes a first bridge arm circuit 101, a second bridge arm circuit 102, a third bridge arm circuit 103, and a fourth bridge arm circuit 104. The first bridge arm circuit 101 is electrically connected to the second bridge arm circuit 102, and the third bridge arm circuit 103 is electrically connected to the fourth bridge arm circuit 104. Each bridge arm circuit includes a switch. The power device under test is located in either the second bridge arm circuit 102 or the fourth bridge arm circuit 104. Specifically, the first bridge arm circuit 101 and the third bridge arm circuit 103 are upper bridge arm circuits, and the second bridge arm circuit 102 and the fourth bridge arm circuit 104 are lower bridge arm circuits; or, the first bridge arm circuit 101 and the third bridge arm circuit 103 are lower bridge arm circuits, and the second bridge arm circuit 102 and the fourth bridge arm circuit 104 are upper bridge arm circuits. Figure 8 The diagram illustrates a scenario where the first bridge arm circuit 101 and the third bridge arm circuit 103 are upper bridge arm circuits, and the second bridge arm circuit 102 and the fourth bridge arm circuit 104 are lower bridge arm circuits, but this is not a limitation. For example... Figure 8As shown, the first bridge arm circuit 101 and the third bridge arm circuit 103 are connected to the first power supply V1, while the second bridge arm circuit 102 and the fourth bridge arm circuit 104 are grounded. The voltage provided by the first power supply is, for example, a positive voltage. Figure 8 As shown, the bridge circuit 10 may also include a first capacitor C1 and a second capacitor C2. The first capacitor C1 and the second capacitor C2 can perform filtering to reduce noise and ensure voltage stability.

[0087] In some implementations... Figure 9 This is a driving timing diagram provided in an embodiment of the present invention. Figure 10 This is a flowchart of another power device testing method provided in an embodiment of the present invention. Optionally, refer to... Figure 8 , Figure 9 and Figure 10 Power device testing methods include:

[0088] S310, control the first bridge arm circuit and the fourth bridge arm circuit to conduct for a first preset time, so as to charge the inductive load according to the first preset time.

[0089] Specifically, when the first bridge arm circuit 101 and the fourth bridge arm circuit 104 are turned on, the first power supply V1, the first bridge arm circuit 101, the inductive load 20, the fourth bridge arm circuit 104 and the ground wire form a charging circuit to charge the inductive load 20.

[0090] For example, such as Figure 9 As shown, the first bridge arm circuit 101, the second bridge arm circuit 102, the third bridge arm circuit 103, and the fourth bridge arm circuit 104 are driven, for example, by pulse width modulation (PWM) signals. PWM1 is the drive signal for the first bridge arm circuit 101, PWM2 is the drive signal for the second bridge arm circuit 102, PWM3 is the drive signal for the third bridge arm circuit 103, and PWM4 is the drive signal for the fourth bridge arm circuit 104. The current waveform of the inductive load 20 is I1. Figure 9 As shown, in stage t1, the first bridge arm circuit 101 and the fourth bridge arm circuit 104 are turned on to charge the inductive load 20, and the current of the inductive load 20 gradually increases.

[0091] S320 controls the second and third bridge arm circuits to conduct.

[0092] Specifically, when the second bridge arm circuit 102 and the third bridge arm circuit 103 are turned on, the first power supply V1, the second bridge arm circuit 102, the inductive load 20, the third bridge arm circuit 103, and the ground wire form a discharge circuit, and the inductive load 20 discharges. Furthermore, the energy of the inductive load can be fed back to the input power supply, resulting in virtually no energy loss during the entire test process, thus effectively reducing power consumption.

[0093] S330: Control the first bridge arm circuit and the third bridge arm circuit to be turned on, and adjust the conduction duration of the first bridge arm circuit to adjust the freewheeling start time so that the discharge duration of the inductive load is the adjusted discharge duration; wherein, when the first bridge arm circuit is turned on, the second bridge arm circuit is turned off; when the first bridge arm circuit is turned off, the second bridge arm circuit is turned on.

[0094] Specifically, by adjusting the conduction duration of the first bridge arm circuit 101, since the charging duration remains constant (the charging duration of each charge-discharge cycle is the same), that is, the time when the conduction of the first bridge arm circuit 101 coincides with the conduction of the fourth bridge arm circuit 104 remains constant, the conduction end time of the first bridge arm circuit 101 will not change when the conduction duration of the first bridge arm circuit 101 is adjusted. This changes the conduction start time of the first bridge arm circuit 101, i.e., changes the freewheeling start time. By advancing the freewheeling start time, the freewheeling phase can be entered earlier, preventing further discharge and thus reducing the discharge duration, increasing the current of the inductive load after the charge-discharge cycle ends. By delaying the freewheeling start time, the freewheeling phase can be entered later, thus increasing the discharge duration and reducing the current of the inductive load after the charge-discharge cycle ends. The advancement or delay of the freewheeling start time can be achieved by adjusting the conduction duration of the first bridge arm circuit 101 to be the same as the conduction duration of the fourth bridge arm circuit 104. That is, the discharge time is adjusted while the discharge time is equal to the charging time.

[0095] For example, such as Figure 9 As shown, in some embodiments, when the conduction duration of the first bridge arm circuit 101 is adjusted to be the same as the conduction duration of the fourth bridge arm circuit 104, the discharge duration is equal to the charging duration. In stage t21, the second bridge arm circuit 102 and the third bridge arm circuit 103 are turned on, the inductive load 20 discharges, and the current of the inductive load 20 decreases to zero (equal to the current at the beginning of this charge / discharge cycle). The current of the inductive load 20 changes according to the trajectory of the first current curve I01. In stage t31, the first bridge arm circuit 101 and the third bridge arm circuit 103 are turned on for freewheeling, and the current of the inductive load 20 remains unchanged.

[0096] In some implementations, when the conduction duration of the first bridge arm circuit 101 is increased, the conduction duration of the second bridge arm circuit 102 is decreased, and the discharge duration is less than the charging duration. In stage t22, the second bridge arm circuit 102 and the third bridge arm circuit 103 are turned on, the inductive load 20 discharges, and the current of the inductive load 20 decreases, but does not reach zero; the current of the inductive load 20 changes according to the trajectory of the second current curve I02. In stage t32, the first bridge arm circuit 101 and the third bridge arm circuit 103 are turned on for freewheeling, and the current of the inductive load 20 remains unchanged.

[0097] In some implementations, when the conduction duration of the second bridge arm circuit 101 decreases, the conduction duration of the second bridge arm circuit 102 increases, and the discharge duration exceeds the charging duration. In stage t23, the second bridge arm circuit 102 and the third bridge arm circuit 103 are turned on, the inductive load 20 discharges, and the current of the inductive load 20 decreases, eventually becoming less than zero. The current of the inductive load 20 changes according to the trajectory of the third current curve I03. In stage t33, the first bridge arm circuit 101 and the third bridge arm circuit 103 are turned on for freewheeling, and the current of the inductive load 20 remains unchanged.

[0098] The technical solution of this embodiment, by setting a freewheeling phase, prevents voltage backflow at the end of the discharge cycle and the beginning of the next charging cycle, which is beneficial to the protection of circuits and devices.

[0099] Furthermore, by turning on the first bridge arm circuit 101 and the third bridge arm circuit 103 after the second bridge arm circuit 102 is turned off, the voltage of the second bridge arm circuit 102 can be released. Thus, when the power device under test is located in the fourth bridge arm circuit 104, a hard-switching mode can be achieved; when the power device under test is located in the second bridge arm circuit 102, a soft-switching module can be achieved. This allows for testing of different switching modes of the power device under test, which helps improve the comprehensiveness and accuracy of the test.

[0100] Furthermore, when the first bridge arm circuit 101 is turned on, the second bridge arm circuit 102 is turned off; when the first bridge arm circuit 101 is turned off, the second bridge arm circuit 102 is turned on. The on-time of the second bridge arm circuit 102 can be reduced by increasing the on-time of the first bridge arm circuit 101, thereby reducing the discharge time. This also prevents two bridge arm circuits located on the same side (connected) from being turned on simultaneously, avoiding the risk of a short circuit.

[0101] S340. Based on the turn-on current and turn-on voltage of the power device under test in each charge and discharge cycle, determine the resistance value of the power device under test in each charge and discharge cycle, so as to test the dynamic resistance of the power device under test.

[0102] Optionally, adjusting the conduction duration of the first bridge arm circuit includes adjusting the pulse width of the drive signal of the first bridge arm circuit. Thus, by adjusting the pulse width (duty cycle) of the drive signal (pulse width modulation signal) corresponding to the first bridge arm circuit 101, the conduction duration of the first bridge arm circuit 101 can be adjusted.

[0103] Based on the above technical solutions, Figure 11 This is a current curve diagram of an inductive load provided in an embodiment of the present invention, such as... Figure 11 As shown, Figure 11The diagram illustrates the changes in the current of the inductive load during multiple charge-discharge cycles. By continuously increasing the conduction time of the first bridge arm circuit 101, the current of the inductive load 20 increases after each charge-discharge cycle, meaning the current of the inductive load 20 gradually increases until it reaches a preset current.

[0104] In some other implementations, Figure 12 This is yet another driving timing diagram provided in the embodiments of the present invention. Figure 13 This is a flowchart of another power device testing method provided in an embodiment of the present invention. Optionally, refer to... Figure 12 and Figure 13 Power device testing methods include:

[0105] S410. Control the first and fourth bridge arm circuits to conduct, and adjust the conduction duration of the first bridge arm circuit to adjust the conduction duration of the second bridge arm circuit; so that the charging duration of the inductive load is either the adjusted charging duration or the unadjusted charging duration; wherein, in different charge and discharge cycles, the start time of the first and fourth bridge arm circuits is the same, but the end time is not exactly the same; when the first bridge arm circuit is on, the second bridge arm circuit is off; when the first bridge arm circuit is off, the second bridge arm circuit is on. The unadjusted charging duration refers to the charging duration when the charging duration is equal to the discharging duration.

[0106] For example, such as Figure 12 As shown, in stage t1', the first bridge arm circuit 101 and the fourth bridge arm circuit 104 are turned on to charge the inductive load 20, and the current of the inductive load 20 gradually increases.

[0107] Specifically, the conduction duration of the first bridge arm circuit 102 can be adjusted by regulating the conduction duration of the first bridge arm circuit 101. This is because the start times of the first bridge arm circuit 101 and the fourth bridge arm circuit 104 are the same. When the conduction duration of the first bridge arm circuit 101 is increased, the end time of the first bridge arm circuit 101 is delayed, resulting in a shorter discharge time. Consequently, the current after the inductive load 20 discharges is greater than the current of the inductive load 20 at the beginning of the current charge / discharge cycle. Similarly, when the conduction duration of the first bridge arm circuit 101 is decreased, the end time of the first bridge arm circuit 101 is advanced, resulting in a shorter charging time. Consequently, the current after the inductive load 20 discharges is less than the current of the inductive load 20 at the beginning of the current charge / discharge cycle.

[0108] S420 controls the second and third bridge arm circuits to conduct so that the discharge duration of the inductive load is either the adjusted discharge duration or the unadjusted discharge duration.

[0109] The discharge duration without adjustment refers to the discharge duration when the charging duration is equal to the discharge duration.

[0110] Specifically, by adjusting the conduction duration of the first bridge arm circuit 101, when the conduction duration of the first bridge arm circuit 101 increases, the discharge start time can be adjusted, thereby adjusting the discharge duration of the inductive load 20. When the conduction duration of the first bridge arm circuit 101 decreases, the charging end time can be adjusted, thereby adjusting the charging duration of the inductive load 20. At this time, the discharge duration is the same as the unadjusted discharge duration.

[0111] For example, such as Figure 12 As shown, in some embodiments, when the on-time of the first bridge arm circuit 101 is the same as the on-time of the fourth bridge arm circuit 104, the discharge duration is equal to the charging duration. In stage t21', the first bridge arm circuit 101 is turned off, and the second bridge arm circuit 102 and the third bridge arm circuit 103 are turned on, causing the inductive load 20 to discharge. The current of the inductive load 20 decreases to zero (equal to the current at the beginning of this charge / discharge cycle). The current of the inductive load 20 changes according to the trajectory of the fourth current curve I11.

[0112] like Figure 12 As shown, in some embodiments, when the conduction duration of the first bridge arm circuit 101 is increased, the conduction duration of the second bridge arm circuit 102 is decreased, and the discharge duration is less than the charging duration. During stage t22', the second bridge arm circuit 102 and the third bridge arm circuit 103 are turned on, the inductive load 20 discharges, and the current of the inductive load 20 decreases, but does not decrease to zero. The current of the inductive load 20 changes according to the trajectory of the fifth current curve I12. In this way, the current of the inductive load 20 is increased, thereby increasing the turn-on current of the power device under test.

[0113] like Figure 12 As shown, in some other embodiments, by reducing the conduction time of the first bridge arm circuit 101, the conduction time of the second bridge arm circuit 102 can be increased, thereby increasing the discharge time and reducing the current of the inductive load 20 after the charging and discharging process. In stage t12', the first bridge arm circuit 101 and the fourth bridge arm circuit 104 are controlled to conduct, charging the inductive load 20. The current of the inductive load 20 gradually increases, but the change is reduced (relative to the change during the charging process when the charging time equals the discharging time). When the conduction time of the first bridge arm circuit 101 decreases, although the conduction time of the second bridge arm circuit 102 increases, since the conduction time of the third bridge arm circuit 102 remains unchanged, the discharge time is the same as the unadjusted discharge time, and the discharge stage remains stage t21', thereby reducing the current of the inductive load 20 after the charging and discharging process. The current of the inductive load 20 changes according to the trajectory of the sixth current curve I13. In this way, the current of the inductive load 20 is reduced, thereby reducing the turn-on current of the power device under test.

[0114] S430. Based on the turn-on current and turn-on voltage of the power device under test in each charge and discharge cycle, determine the resistance value of the power device under test in each charge and discharge cycle, so as to test the dynamic resistance of the power device under test.

[0115] The following explanation of the relationship between the discharge duration and the conduction duration of the first bridge arm circuit is not intended to limit this application.

[0116] Based on the above technical solutions, optionally, the conduction duration of the first bridge arm circuit can be adjusted to adjust the freewheeling start time, including:

[0117] Increase the conduction time of the first bridge arm circuit so that the adjusted discharge time is less than the charging time of the inductive load.

[0118] For example, in some embodiments, when it is necessary to increase the current of the inductive load at the end of the current charge-discharge cycle, the conduction time of the first bridge arm circuit 101 is increased, so that the conduction start time of the first bridge arm circuit 101 is advanced. That is, before the conduction time of the second bridge arm circuit 102 and the third bridge arm circuit 103 reaches the first preset time, the first bridge arm circuit 101 is turned on (while the second bridge arm circuit 102 is turned off), and it enters the freewheeling stage earlier, unable to continue discharging, thereby reducing the discharge time. Similarly, when it is necessary to reduce the current of the inductive load at the end of the current charge-discharge cycle, the conduction time of the first bridge arm circuit 101 is decreased, so that the conduction start time of the first bridge arm circuit 101 is delayed. That is, after the conduction time of the second bridge arm circuit 102 and the third bridge arm circuit 103 reaches the first preset time for a period of time, the first bridge arm circuit 101 is turned on, thereby increasing the discharge time. In this way, the discharge time of the inductive load can be adjusted by adjusting the conduction time of the first bridge arm circuit 101.

[0119] In other embodiments, when it is necessary to increase the current of the inductive load at the end of the current charge-discharge cycle, the conduction time of the first bridge arm circuit 101 is increased (i.e., the pulse width of the PWM signal corresponding to the first bridge arm circuit 101 is increased), which reduces the conduction time of the second bridge arm circuit 102, delaying the time to enter the discharge stage, thereby reducing the discharge duration. Similarly, when it is necessary to reduce the current of the inductive load at the end of the current charge-discharge cycle, the conduction time of the first bridge arm circuit 101 is decreased (i.e., the pulse width of the PWM signal corresponding to the first bridge arm circuit 101 is decreased), which increases the conduction time of the second bridge arm circuit 102, reducing the charging duration, thereby reducing the current of the inductive load at the end of the current charge-discharge cycle.

[0120] As a further implementation of this embodiment, based on the above technical solutions, in order to prevent voltage backflow, a freewheeling stage can be added between the charging and discharging stages of the inductive load. The following is a detailed explanation... Figure 8 , Figure 9 and Figure 12 The driving process of the freewheeling phase between the charging and discharging phases is described, but this is not intended to limit the scope of this application.

[0121] In some implementations, alternatively, reference is made to Figure 8 and Figure 9 Before the bridge circuit discharges the inductive load according to the adjusted discharge duration, the following steps are also included:

[0122] The second and fourth bridge arm circuits are controlled to conduct in order to provide freewheeling current for the inductive load.

[0123] Specifically, by controlling the second bridge arm circuit 102 and the fourth bridge arm circuit 104 to conduct between the charging and discharging phases in a charge-discharge cycle, the current circulates between the second bridge arm circuit 102, the inductive load 20, and the fourth bridge arm circuit 104, providing freewheeling current for the inductive load 20. This avoids voltage backflow caused by the inductive load 20 discharging immediately after charging, which is beneficial for circuit protection.

[0124] In some other implementations, alternatively, refer to Figure 8 and Figure 12 Before the bridge circuit discharges the inductive load according to the adjusted discharge duration, the following steps are also included:

[0125] The first, second, third, and fourth bridge arm circuits are turned off to allow current to flow to the inductive load.

[0126] Specifically, when the conduction duration of the first bridge arm circuit 101 is equal to that of the second bridge arm circuit 102, that is, when the conduction duration of all bridge arm circuits is equal, the first bridge arm circuit 101, the second bridge arm circuit 102, the third bridge arm circuit 103 and the fourth bridge arm circuit 104 are turned off between the charging and discharging phases, so that the inductive load 20 cannot be charged and discharged, thereby maintaining the current and achieving the effect of freewheeling.

[0127] Furthermore, by controlling the turn-off of the first bridge arm circuit 101, the second bridge arm circuit 102, the third bridge arm circuit 103, and the fourth bridge arm circuit 104, a portion of the voltage of the power device under test can be released, achieving a semi-soft switching mode. Thus, the switching mode can be controlled by adjusting the turn-on timing, which is beneficial for testing the dynamic characteristics of the power device under test under different switching modules.

[0128] In some other implementations, alternatively, refer to Figure 8 and Figure 12Before the bridge circuit discharges the inductive load according to the adjusted discharge duration, the method further includes: controlling the first bridge arm circuit and the third bridge arm circuit to conduct in order to provide freewheeling current for the inductive load.

[0129] When the fourth bridge arm circuit 104 is turned on, the third bridge arm circuit 103 is turned off; when the fourth bridge arm circuit 104 is turned off, the third bridge arm circuit 103 is turned on.

[0130] Specifically, when the conduction end time of the first bridge arm circuit 101 is later than the conduction end time of the fourth bridge arm circuit 104, after charging is completed, the fourth bridge arm circuit 104 is turned off and the third bridge arm circuit 103 is turned on, thereby enabling the first bridge arm circuit 101 and the third bridge arm circuit 103 to conduct. The current circulates between the first bridge arm circuit 101, the inductive load 20 and the third bridge arm circuit 103, avoiding the situation where the inductive load 20 discharges immediately after charging and causes voltage backflow, which is beneficial to the protection circuit.

[0131] Based on the above technical solutions, optionally, the discharge duration or charging duration of the inductive load in each charge-discharge cycle can be adjusted, including:

[0132] The discharge or charging duration of the inductive load in each charge-discharge cycle is adjusted according to the closed-loop control strategy and the preset current; wherein, the closed-loop control strategy includes proportional-integral-derivative control strategy or proportional-integral control strategy.

[0133] Specifically, by employing a closed-loop control strategy, the closed-loop control adjusts the discharge or charging duration of each charge-discharge cycle with a preset current as the target. This ensures that at the end of each charge-discharge cycle, the current in the inductive load is close to or equal to the preset current, thereby guaranteeing a constant turn-on current for the power device under test (DDT), which is beneficial for testing the DDT. Furthermore, when adjusting the input voltage of the bridge circuit, the closed-loop control strategy still adjusts the discharge or charging duration of each charge-discharge cycle with the preset current as the target. Therefore, changes in the input voltage do not affect changes in the turn-on current of the DDT, facilitating accurate setting of the DDT's current and improving the accuracy of the DDT testing.

[0134] This embodiment also provides a power device testing apparatus. Figure 14 This is a schematic diagram of the structure of a power device testing device provided in an embodiment of the present invention, as shown below. Figure 14As shown, the device includes: a bridge circuit 10, an inductive load 20, and a control module 30; the control module 30 is used to execute the power device testing method provided in any of the above embodiments; the bridge circuit 10 is connected to the inductive load 20; the control module 30 is connected to the bridge circuit 10, and the control module 30 is used to control the bridge circuit 10 to charge and discharge the inductive load 20, and adjust the discharge duration or charging duration of the inductive load 20 in each charge and discharge cycle, so that the turn-on current of the power device under test gradually reaches the preset current and maintains the turn-on current at the preset current; and based on the turn-on current and turn-on voltage of the power device under test in each charge and discharge cycle, the resistance value of the power device under test in each charge and discharge cycle is determined to test the dynamic resistance of the power device under test.

[0135] Specifically, the control module 30 can control the conduction sequence of the bridge circuit 10, thereby controlling the charging and discharging processes of the inductive load 20, and further controlling the discharge or charging duration of the inductive load 20. This adjusts the current value of the inductive load 20 after each charge / discharge cycle, thereby adjusting the turn-on current of the power device under test (DUT) and maintaining it at a preset current. Thus, adjusting the preset current in the control module 30 is sufficient to regulate the turn-on current of the DUT. Adjusting the input voltage does not affect the turn-on current, allowing for independent adjustment of both the input voltage and the turn-on current. This is beneficial for testing the dynamic resistance of the DUT under different operating conditions.

[0136] Based on the above technical solutions, Figure 15 This is a schematic diagram of another power device testing device provided in an embodiment of the present invention. Optionally, refer to... Figure 15 The bridge circuit 10 includes: a first bridge arm circuit 101, a second bridge arm circuit 102, a third bridge arm circuit 103, and a fourth bridge arm circuit 104. Each bridge arm circuit includes a switch. The power device under test is located in the second bridge arm circuit 102 or the fourth bridge arm circuit 104. The first end of the first bridge arm circuit 101 is connected to a first power supply V1. The first end of the second bridge arm circuit 102 is electrically connected to the second end of the first bridge arm circuit 101, and the second end of the second bridge arm circuit 102 is connected to a second power supply. The first end of the third bridge arm circuit 103 is connected to the first power supply. The first end of the fourth bridge arm circuit 104 is electrically connected to the second end of the third bridge arm circuit 103, and the second end of the fourth bridge arm circuit 104 is connected to the second power supply. An inductive load 20 is connected between the second end of the first bridge arm circuit 101 and the second end of the third bridge arm circuit 103.

[0137] Optionally, the power device under test is located in the fourth bridge arm circuit 104. Thus, when the first bridge arm circuit 101 and the fourth bridge arm circuit 104 are turned on, the current in the fourth bridge arm circuit 104 is the same as the current in the inductive load 20, the voltage in the fourth bridge arm circuit 104 is the same as the voltage in the inductive load 20, and the turn-on trajectory of the power device under test is the same as the turn-on trajectory of the inductive load 20.

[0138] The voltage provided by the first power source is, for example, a positive voltage, and the voltage provided by the second power source is, for example, zero or a negative voltage. When the voltage provided by the second power source is zero, the second power source is grounded. Figure 15 The example shows the case where the second power source is grounded, but it is not limited to that case.

[0139] Optionally, such as Figure 15 As shown, the first bridge arm circuit 101 includes a first switch Q1, the second bridge arm circuit 102 includes a second switch Q2, the third bridge arm circuit 103 includes a third switch Q3, and the fourth bridge arm circuit 14 includes a fourth switch Q4 (the power device under test).

[0140] Optionally, refer to Figure 15 The testing device also includes a test resistor R; the test resistor R is connected between the second end of the second bridge arm circuit 102 and the second end of the fourth bridge arm circuit 104; the control module 30 is connected to the test resistor R, and the control module 30 is also used to obtain the turn-on current of the power device under test through the test resistor R.

[0141] Specifically, the current in the bridge circuit can be collected by testing the resistor R, thereby obtaining the turn-on current of the power device under test. When the first bridge arm circuit 101 and the fourth bridge arm circuit 104 are conducting, the current in the test resistor R is the same as the current in the inductive load 20. When the second bridge arm circuit 102 and the fourth bridge arm circuit 104 are conducting, the current in the test resistor R is the same as the current in the inductive load 20. Thus, the current in the inductive load 20 and the fourth bridge arm circuit 104 (the power device under test) can be obtained by testing the resistor R.

[0142] Optionally, refer to Figure 15The testing device also includes a first drive module 40 and a second drive module 50. The first drive module 40 is connected between the control module 30 and the control terminal of the first bridge arm circuit 101, and between the control module 30 and the control terminal of the second bridge arm circuit 102. The second drive module 50 is connected between the control module 30 and the control terminal of the third bridge arm circuit 103, and between the control module 30 and the control terminal of the fourth bridge arm circuit 104. Because when the first bridge arm circuit 101 is on, the second bridge arm circuit 102 is off; when the third bridge arm circuit 103 is on, the fourth bridge arm circuit 104 is off, so at the same time, the level signals of the control terminals of the first bridge arm circuit 101 and the second bridge arm circuit 102 are opposite, and the level signals of the control terminals of the third bridge arm circuit 103 and the fourth bridge arm circuit 104 are opposite. The first drive module 40 and the second drive module 50 include drive circuits that can drive the corresponding bridge arm circuits (switches) to turn on and off according to the pulse width modulation signal (PWM signal) output by the control module 30. In this way, the conduction frequency of each bridge arm circuit (switch) and the duty cycle of the control signal are not limited by the input voltage, the inductance of the inductive load and the turn-on current of the power device under test, and the conduction frequency of each bridge arm circuit (switch) and the duty cycle of the control signal can be easily modified.

[0143] It should be noted that the technical solution in this embodiment only illustrates the situation where each bridge arm circuit is turned on when the level is high and turned off when the level is low, but it does not limit the scope of the solution.

[0144] Optionally, such as Figure 15 As shown, the control module 30 includes a host computer 31 and a digital signal processor 32. The host computer 31 is connected to the digital signal processor 32, and the digital signal processor 32 is connected to the first drive module 40 and the second drive module 50, respectively. The host computer 31 can modify the preset current and send the preset current to the digital signal processor 32. The digital signal processor 32 generates control signals (PWM signals) for each bridge arm circuit (switch) according to the preset current, so that the first drive module 40 and the second drive module 50 drive the corresponding bridge arm circuit (switch) to conduct according to the PWM signal, so that the current of the inductive load 20 is maintained at the preset current, that is, the current of the measured power device is maintained at the preset current.

[0145] Optionally, such as Figure 15As shown, the control module 30 also includes an operational amplifier 33, which is electrically connected to the test resistor R and the digital signal processor 32. The operational amplifier 33 can acquire the current of the test resistor R, amplify it, and transmit it to the digital signal processor 32. Based on the current of the test circuit R, the digital signal processor 32 can determine the actual current of the inductive load 20, and then adjust the current of the inductive load 20 according to the actual current of the inductive load 20 and the preset current based on the closed-loop control strategy, so that the current of the inductive load 20 is maintained at the preset current, that is, the current of the power device under test is maintained at the preset current.

[0146] Optionally, such as Figure 15 As shown, the control module 30 also includes a power supply unit 34, which is connected to the digital signal processor 32, the first drive module 40, and the second drive module 50. The power supply unit 34 provides power to the digital signal processor 32, the first drive module 40, and the second drive module 50, facilitating their normal operation. The power supply unit 34 may include a voltage conversion circuit, such as a DC-DC conversion circuit, but this embodiment does not limit its application.

[0147] The control module in the power device testing apparatus provided in the embodiments of the present invention can execute the power device testing method provided in any embodiment of the present invention. Therefore, the power device testing apparatus has the same beneficial effects as the power device testing method provided in any embodiment of the present invention, which will not be elaborated here.

[0148] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0149] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for testing power devices, characterized in that, The test method is implemented by a power device test device, which includes a bridge circuit and an inductive load. The bridge circuit includes multiple switches, and the power device under test is one of the switches in the bridge circuit. The testing method includes: The bridge circuit is controlled to charge and discharge the inductive load, and the discharge duration or charging duration of the inductive load in each charge and discharge cycle is adjusted so that the turn-on current of the power device under test gradually reaches the preset current and the turn-on current is maintained at the preset current. Based on the turn-on current and turn-on voltage of the power device under test in each charge-discharge cycle, the resistance value of the power device under test in each charge-discharge cycle is determined to test the dynamic resistance of the power device under test.

2. The method according to claim 1, characterized in that, Controlling the bridge circuit to charge and discharge the inductive load, and adjusting the discharge duration of the inductive load in each charge and discharge cycle, so that the turn-on current of the power device under test gradually reaches the preset current, and maintaining the turn-on current at the preset current, includes: The bridge circuit is controlled to charge the inductive load for a first preset duration. The discharge duration of the inductive load in each charge-discharge cycle is adjusted, and the bridge circuit is controlled to discharge the inductive load according to the adjusted discharge duration; wherein, the discharge duration of the inductive load is not exactly the same as the charging duration of the inductive load; the discharge duration of the inductive load is not exactly the same in different charge-discharge cycles.

3. The method according to claim 2, characterized in that, The bridge circuit includes a first bridge arm circuit, a second bridge arm circuit, a third bridge arm circuit, and a fourth bridge arm circuit. The first bridge arm circuit is electrically connected to the second bridge arm circuit, and the third bridge arm circuit is electrically connected to the fourth bridge arm circuit. Each bridge arm circuit includes a switch. The power device under test is located in the second bridge arm circuit or the fourth bridge arm circuit. The control of the bridge circuit to charge the inductive load for a first preset duration includes: The first bridge arm circuit and the fourth bridge arm circuit are controlled to conduct for the first preset duration so as to charge the inductive load according to the first preset duration; And / or, adjusting the discharge duration of the inductive load in each charge-discharge cycle, and controlling the bridge circuit to discharge the inductive load according to the adjusted discharge duration, including: Control the second bridge arm circuit and the third bridge arm circuit to conduct; The first bridge arm circuit and the third bridge arm circuit are controlled to be turned on, and the on-time of the first bridge arm circuit is adjusted to adjust the freewheeling start time so that the discharge time of the inductive load is the adjusted discharge time; wherein, when the first bridge arm circuit is turned on, the second bridge arm circuit is turned off; when the first bridge arm circuit is turned off, the second bridge arm circuit is turned on.

4. The method according to claim 1, characterized in that, The bridge circuit includes a first bridge arm circuit, a second bridge arm circuit, a third bridge arm circuit, and a fourth bridge arm circuit. The first bridge arm circuit is electrically connected to the second bridge arm circuit, and the third bridge arm circuit is electrically connected to the fourth bridge arm circuit. Each bridge arm circuit includes a switch. The power device under test is located in the second bridge arm circuit or the fourth bridge arm circuit. The step of controlling the bridge circuit to charge and discharge the inductive load, and adjusting the discharge duration or charging duration of the inductive load in each charge-discharge cycle, so that the turn-on current of the power device under test gradually reaches the preset current, and maintaining the turn-on current at the preset current, includes: The first bridge arm circuit and the fourth bridge arm circuit are controlled to be turned on, and the on-time of the first bridge arm circuit is adjusted to adjust the on-time of the second bridge arm circuit; so that the charging time of the inductive load is either the adjusted charging time or the unadjusted charging time; wherein, in different charge and discharge cycles, the start time of the first bridge arm circuit and the fourth bridge arm circuit being turned on is the same, but the end time is not exactly the same; when the first bridge arm circuit is turned on, the second bridge arm circuit is turned off; when the first bridge arm circuit is turned off, the second bridge arm circuit is turned on. The second bridge arm circuit and the third bridge arm circuit are controlled to be turned on so that the discharge duration of the inductive load is either the adjusted discharge duration or the unadjusted discharge duration.

5. The method according to claim 3 or 4, characterized in that, Adjusting the conduction duration of the first bridge arm circuit includes: Increase the conduction time of the first bridge arm circuit so that the adjusted discharge time is less than the charging time of the inductive load.

6. The method according to claim 3 or 4, characterized in that, Before controlling the bridge circuit to discharge the inductive load according to the adjusted discharge duration, the method further includes: The second bridge arm circuit and the fourth bridge arm circuit are turned on, or the first bridge arm circuit and the third bridge arm circuit are turned on, or the first bridge arm circuit, the second bridge arm circuit, the third bridge arm circuit and the fourth bridge arm circuit are turned off, so as to provide freewheeling current for the inductive load.

7. The method according to claim 1, characterized in that, The adjustment of the discharge duration or charging duration of the inductive load in each charge-discharge cycle includes: The discharge duration or charging duration of the inductive load in each charge-discharge cycle is adjusted according to the closed-loop control strategy and the preset current; wherein, the closed-loop control strategy includes a proportional-integral-derivative control strategy or a proportional-integral control strategy.

8. A power device testing apparatus, characterized in that, It includes a bridge circuit, an inductive load, and a control module; the control module is used to execute the power device testing method according to any one of claims 1-7; the bridge circuit is connected to the inductive load; The control module is connected to the bridge circuit. The control module is used to control the bridge circuit to charge and discharge the inductive load, and to adjust the discharge duration or charging duration of the inductive load in each charge and discharge cycle, so that the turn-on current of the power device under test gradually reaches the preset current, and maintains the turn-on current at the preset current. Based on the turn-on current and turn-on voltage of the power device under test in each charge-discharge cycle, the resistance value of the power device under test in each charge-discharge cycle is determined to test the dynamic resistance of the power device under test.

9. The power device testing apparatus according to claim 8, characterized in that, The bridge circuit includes: The circuit comprises a first bridge arm circuit, a second bridge arm circuit, a third bridge arm circuit, and a fourth bridge arm circuit, each bridge arm circuit including one of the aforementioned switches; the power device under test is located in the second bridge arm circuit or the fourth bridge arm circuit. The first end of the first bridge arm circuit is connected to the first power supply; the first end of the second bridge arm circuit is electrically connected to the second end of the first bridge arm circuit, and the second end of the second bridge arm circuit is connected to the second power supply. The first end of the third bridge arm circuit is connected to the first power supply; the first end of the fourth bridge arm circuit is electrically connected to the second end of the third bridge arm circuit, and the second end of the fourth bridge arm circuit is connected to the second power supply. The inductive load is connected between the second end of the first bridge arm circuit and the second end of the third bridge arm circuit.

10. The power device testing apparatus according to claim 9, characterized in that, The testing device also includes a test resistor; The test resistor is connected between the second terminal of the second bridge arm circuit and the second terminal of the fourth bridge arm circuit. The control module is connected to the test resistor, and the control module is also used to obtain the turn-on current of the power device under test through the test resistor.

Images