A method and system for testing a power module
By controlling the on and off states of all power devices in the power module, and combining this with discharge measurements of the energy storage module and load module, the accuracy problem of stray inductance testing in the power module was solved, achieving higher testing precision and inductance determination.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YOFC ADVANCED SEMICONDUCTOR (WUHAN) CO LTD
- Filing Date
- 2026-03-18
- Publication Date
- 2026-06-12
AI Technical Summary
The accuracy of stray inductance testing for existing power modules is low, mainly due to unstable voltage plateau and unstable current change rate caused by fast switching speed.
By controlling all power devices in the power module under test to be turned on and off, and utilizing the coordinated discharge of the energy storage module and the load module, the voltage and current change rates of the power devices are measured to determine the first and second stray inductances. These are then combined with the Kelvin terminal voltage to calculate the target stray inductance of each power device, ultimately determining the stray inductance of the power module under test.
It improves the testing accuracy of stray inductance in power modules, avoids the introduction of excessive stray inductance, ensures a clear voltage plateau and a significant current change rate, and enhances the accuracy of the test.
Smart Images
Figure CN122193710A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power device testing technology, and in particular to a testing method and system for power modules. Background Technology
[0002] A power module is an electronic product composed of power semiconductor devices combined and packaged according to their circuit functions. The core function of a power module is power conversion and control. These power semiconductor devices can include insulated-gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs), with MOSFETs being silicon carbide (SiC) MOSFETs, among others.
[0003] To ensure better application of power modules, testing is necessary, such as testing their stray inductance. Current testing methods involve connecting an auxiliary switch in series with the power module. A dual-pulse control signal is output to the auxiliary switch to control its on / off state. When the auxiliary switch is turned on for the first time, the power module conducts, and its current rises. When the auxiliary switch is turned on for the second time, the power module is turned off, and its current drops rapidly, resulting in a voltage plateau. The ratio of the voltage plateau value to the rate of change of current during the rapid current drop is used as the stray inductance of the power module.
[0004] However, due to the fast switching speed of the power module, the voltage platform is unstable, which affects the voltage judgment. Furthermore, the rate of change of the current when it drops rapidly is unstable, resulting in low accuracy of the determined stray inductance of the power module. Summary of the Invention
[0005] This invention provides a testing method and system for power modules to improve the accuracy of stray inductance testing of power modules.
[0006] According to one aspect of the present invention, a testing method for a power module is provided, implemented by a power module testing system. The power module testing system includes an energy storage module, a load module, and a power module under test. A first terminal of the energy storage module is connected to a first terminal of an external power supply, and a second terminal of the energy storage module is connected to a second terminal of the external power supply. The load module and the power module under test are connected in series between the first terminal and the second terminal of the energy storage module. The power module under test includes at least one power conversion circuit, and the power conversion circuit includes at least one power device. The method includes: All power devices in the power module under test are turned on. The first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device; wherein the first terminal and the second terminal of the power device are connected to a device other than the power device. The second stray inductance is determined based on the second voltage between the first Kelvin terminal and the second Kelvin terminal of the power device and the second current change rate of the power device; wherein the first Kelvin terminal of the power device is connected to the first terminal of the power device, and the second Kelvin terminal of the power device is connected to the second terminal of the power device. The first target stray inductance of the power device is determined based on the first stray inductance and the second stray inductance; The second target stray inductance of the power module under test is determined based on the first target stray inductance of all power devices in the power module under test.
[0007] Optionally, controlling all power devices in the power module under test to be turned on includes: The first turn-on of all power devices in the power module under test is controlled. All power devices in the power module under test are turned off. Control all power devices in the power module under test to conduct for the second time.
[0008] Optionally, determining the first stray inductance based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device includes: The ratio of the difference between the third voltage and the first voltage between the first terminal and the second terminal of the energy storage module to the first current change rate is used as the first stray inductance. The second stray inductance is determined based on the second voltage between the first Kelvin terminal and the second Kelvin terminal of the power device and the second current change rate of the power device, including: The ratio of the difference between the fourth voltage and the second voltage between the first terminal and the second terminal of the energy storage module to the second current change rate is used as the second stray inductance.
[0009] Optionally, determining the first target stray inductance of the power device based on the first stray inductance and the second stray inductance includes: The difference between the second stray inductance and the first stray inductance is used as the first target stray inductance of the power device.
[0010] Optionally, before determining the first stray inductance based on the first voltage between the first power terminal and the second power terminal of the power device and the first current change rate of the power device, the method further includes: Determine the first initial current change rate at each sampling point when the power device is turned on for the second time; The maximum value among all the first initial current change rates is taken as the first current change rate.
[0011] Optionally, the power module under test includes a substrate, the power conversion circuit is located on the substrate, the power conversion circuit includes two power devices, the two power devices include a first power device and a second power device, the first terminal of the first power device is connected to the load module, the second terminal of the first power device and the first terminal of the second power device are connected to a first connection point, and the second terminal of the second power device is connected to a second end of the energy storage module; wherein, the first connection point is located on the substrate; For the first power device, determining the first stray inductance based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device includes: The first stray inductance of the first power device is determined based on the first voltage between the first terminal of the first power device and the first connection point and the first current change rate of the first power device. For the second power device, the first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device, including: The first stray inductance of the second power device is determined based on the first voltage between the second terminal of the second power device and the first connection point and the first current change rate of the second power device.
[0012] Optionally, the power conversion circuit includes a power device; the first terminal of the power device is connected to the load module, and the second terminal of the power device is connected to the second terminal of the energy storage module; The first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device, including: The first stray inductance of the power device is determined based on the first voltage between the first power terminal and the second power terminal of the power device and the first current change rate of the power device.
[0013] Optionally, determining the second target stray inductance of the power module under test based on the first target stray inductance of all power devices in the power module under test includes: The sum of the first target stray inductances of all power devices in the power module under test is taken as the second target stray inductance.
[0014] According to another aspect of the present invention, a test system for a power module is provided, comprising an energy storage module, a load module, a power module under test, and a control module. The first end of the energy storage module is connected to the first end of the external power supply, and the second end of the energy storage module is connected to the second end of the external power supply; the load module and the power under test module are connected in series between the first end and the second end of the energy storage module; the power under test module includes at least one power conversion circuit, and the power conversion circuit includes at least one power device. The control module is connected to the control terminal of the power device and the second Kelvin terminal of the power device. The control module is used to execute the test method of the power module according to any embodiment of the present invention.
[0015] Optionally, the test system for the power module further includes a freewheeling module; The continuous current module is connected in parallel with the load module.
[0016] The technical solution of this invention involves controlling all power devices in the power module under test to be turned on. When all power devices are turned on, a first stray inductance is determined based on a first voltage between the first and second terminals of the power devices and a first current change rate of the power devices. A second stray inductance is determined based on a second voltage between the first and second Kelvin terminals of the power devices and a second current change rate of the power devices. A first target stray inductance of the power devices is determined based on the first and second stray inductances. A second target stray inductance of the power module under test is determined based on the first target stray inductances of all power devices in the power module under test. By controlling the turn-on or turn-off of the power module under test to detect the second target stray inductance, when the power module under test is turned on, both the energy storage module and the load module can discharge through the power module under test, resulting in a larger current flowing through the power module under test, a more obvious voltage plateau when the voltage of the power module under test is stable, and a more obvious current change rate of the power module under test, thereby improving the accuracy of determining the stray inductance of the power module under test. Furthermore, by determining the sum of the stray inductance between the first Kelvin terminal and the first terminal of the power device and the stray inductance between the second Kelvin terminal and the second terminal of the power device as the first target stray inductance of the power device, excessive stray inductance of the power device can be avoided. For example, stray inductance between the power device and subsequent circuits can be avoided, thus achieving the effect of accurately determining the first target stray inductance of each power device and further improving the accuracy of stray inductance determination of the power module under test.
[0017] 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
[0018] 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.
[0019] Figure 1 This is a schematic diagram of the structure of a test circuit for a power module in related technologies; Figure 2 This is a schematic diagram of the circuit structure of a power module testing system provided in an embodiment of the present invention; Figure 3 This is a flowchart of a power module testing method provided in an embodiment of the present invention; Figure 4 This is a flowchart of another power module testing method provided in an embodiment of the present invention; Figure 5 This is a flowchart of another power module testing method provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the circuit structure of another power module test system provided in an embodiment of the present invention; Figure 7 This is a circuit structure diagram of another power module testing system provided in an embodiment of the present invention. Detailed Implementation
[0020] 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.
[0021] 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 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.
[0022] Figure 1 This is a schematic diagram of the structure of a test circuit for a power module in related technologies, such as... Figure 1As shown, the test circuit for the power module includes a voltage source U0, a capacitor C0, an auxiliary switch T03, a power module DUT, and a load inductor L0. The power module DUT includes a first power transistor T01 and a second power transistor T02. The auxiliary switch T03 is connected in series with the power module DUT. By outputting a dual-pulse control signal P0 to the auxiliary switch T03, the on / off state of the auxiliary switch T03 is controlled. When the auxiliary switch T03 is turned on for the first time, the power module DUT is turned on, and the current of the power module DUT increases. During the interval between the two on / off states, the auxiliary switch T03 is turned off, and the power module DUT and the load inductor L0 continue to flow. When the auxiliary switch T03 is turned on for the second time, the power module DUT is turned off, and the current of the power module DUT drops rapidly. After the voltage of the power module DUT stabilizes, a voltage plateau appears. The ratio of the voltage value corresponding to the voltage plateau to the rate of change of the current during the rapid current drop is taken as the stray inductance of the power module DUT.
[0023] However, due to the high switching speed of the power module DUT, the voltage plateau is unstable, affecting voltage judgment. Furthermore, the rate of change of current during rapid drops is unstable, leading to low accuracy in determining the stray inductance of the power module DUT. Additionally, when a voltage plateau occurs, the current decreases, resulting in a smaller voltage value corresponding to the plateau, making it difficult to accurately measure the voltage and current change rates, thus further reducing the accuracy of determining the stray inductance of the power module.
[0024] To address the aforementioned technical problems, embodiments of the present invention provide a testing method for a power module, implemented by a power module testing system. Figure 2 This is a circuit structure diagram of a power module testing system provided in an embodiment of the present invention, for reference. Figure 2The power module test system includes an energy storage module 101, a load module 102, and a power module under test 103. The first terminal of the energy storage module 101 is connected to the first terminal of an external power supply 200, and the second terminal of the energy storage module 101 is also connected to the second terminal of the external power supply 200. The load module 102 and the power module under test 103 are connected in series between the first and second terminals of the energy storage module 101. The power module under test 103 includes at least one power conversion circuit 131, which includes at least one power device T1. The external power supply 200 can charge the energy storage module 101, allowing it to discharge through the power module under test 103. The energy storage module 101 may include at least one capacitor, or for example, multiple capacitors connected in parallel. The power module under test 103 includes at least one power conversion circuit 131, which can form a half-bridge circuit. Alternatively, the power module under test 103 may include two parallel power conversion circuits 131, forming a single-phase H-bridge circuit. Alternatively, the power module under test 103 may include three power conversion circuits 131, forming a three-phase full-bridge circuit. Each power conversion circuit 131 includes at least one power device T1, which may be an IGBT or a MOSFET, and the MOSFET may be a silicon carbide (SiC) MOSFET. When the power conversion circuit 131 includes at least two power devices T1, the power devices T1 in the power conversion circuit 131 may be connected in series.
[0025] The load module 102 may include capacitors, inductors or resistors, etc., and is not limited thereto.
[0026] Figure 3 This is a flowchart of a power module testing method provided in an embodiment of the present invention, see reference. Figure 3 The testing methods for power modules include: S110: Ensure all power devices in the power module under test are turned on.
[0027] Specifically, a turn-on control signal can be sent to each power device T1, causing all power devices T1 in the power module under test 103 to be turned on simultaneously. Then, for each power device T1, steps S120 to S140 are executed to determine the first target stray inductance of each power device T1.
[0028] By controlling the on or off of all power devices in the power module under test 103, the power module under test 103 can charge the load module 102 when it is turned on for the first time. When the power module under test 103 is turned on for the second time, both the energy storage module 101 and the load module 102 discharge. This makes the voltage plateau of the power module under test 103 when the voltage is stable more obvious, and the current change rate of the power module under test 103 more obvious, which can improve the accuracy of determining the stray inductance of the power module under test 103.
[0029] S120. Determine the first stray inductance based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device; wherein the first terminal and the second terminal of the power device are connected to devices other than the power device.
[0030] The power module under test may include a substrate, on which power devices are located. The first terminal P1 and the second terminal P2 of the power device are terminals for connecting the power device to other devices. When the power conversion circuit 131 includes a power device T1, the first terminal P1 of the power device T1 is the terminal connected to the load module 102, and the second terminal P2 of the power device T1 is the terminal connected to the second terminal of the energy storage module 101. In this case, both the first terminal P1 and the second terminal P2 of the power device T1 are power terminals, which can be connected using copper busbars. Figure 2 As shown, when the power conversion circuit 131 includes two power devices T1, the two power devices T1 include a first power device T11 and a second power device T12. The first terminal P11 of the first power device T11 is connected to the load module 102, the second terminal P12 of the first power device T11 is connected to the first terminal of the second power device T12, and the second terminal P22 of the second power device T12 is connected to the second end of the energy storage module 101. At this time, the first terminal P11 of the first power device T11 and the second terminal P22 of the second power device T12 are power terminals, and the second terminal P12 of the first power device T11 and the first terminal P21 of the second power device T12 are connection points on the substrate.
[0031] Specifically, based on the first voltage between the first terminal P1 and the second terminal P2 of power device T1, the voltages other than those between the first and second terminals P1 and P2 of power device T1 can be determined. Based on these voltages and the first rate of change of current, the stray inductances other than those between the first and second terminals P1 and P2 of power device T1 can be determined; this is the first stray inductance corresponding to power device T1. Here, the first rate of change of current can be the maximum rate of change of current of power device T1 during its current conduction phase. The first voltage is the voltage between the first and second terminals P1 and P2 of power device T1 at the moment corresponding to the first rate of change of current, and it is also the voltage after the voltages between the first and second terminals P1 and P2 of power device T1 have stabilized; that is, the first voltage is the voltage corresponding to the voltage plateau of the first and second terminals P1 and P2 of power device T1.
[0032] When the power module under test 103 is turned on, and both the energy storage module 101 and the load module 102 discharge through the power module under test 103, the first current change rate is more obvious and the first voltage is larger, which makes it easier to accurately measure the first voltage and the first current change rate, thereby improving the accuracy of determining the first stray inductance, and further improving the accuracy of determining the stray inductance of the power module under test 103.
[0033] S130. Determine the second stray inductance based on the second voltage between the first Kelvin terminal and the second Kelvin terminal of the power device and the second current change rate of the power device; wherein the first Kelvin terminal of the power device is connected to the first terminal of the power device, and the second Kelvin terminal of the power device is connected to the second terminal of the power device.
[0034] In this design, the Kelvin terminal (first or second Kelvin terminal) of the power device serves to establish a channel between the Kelvin terminal and the power terminal through packaging technology. This separates the drive circuit and the power circuit, reducing the interference of parasitic inductance on the gate voltage of the power device and thus optimizing the device's switching performance. The core principle of the Kelvin terminal lies in decoupling the drive and power circuits. For example, ... Figure 2As shown, the power conversion circuit 131 includes two power devices T1, namely a first power device T11 and a second power device T12. The first Kelvin terminal P13 of the first power device T11 is connected to the first terminal P11 of the first power device T11, and the second Kelvin terminal P14 of the first power device T11 is connected to the second terminal P12 of the first power device T11. The first Kelvin terminal P23 of the second power device T12 is connected to the first terminal P21 of the second power device T12, and the second Kelvin terminal P24 of the second power device T12 is connected to the second terminal P22 of the second power device T12.
[0035] Specifically, based on the second voltage between the first Kelvin terminal and the second Kelvin terminal of the power device, the voltages outside the first Kelvin terminal and the second Kelvin terminal of the power device can be determined. Based on these voltages and the second current change rate, the stray inductances outside the first Kelvin terminal and the second Kelvin terminal of the power device can be determined; this is the second stray inductance corresponding to power device T1. For example, for the first power device T11, based on the voltage between the first Kelvin terminal P13 and the second Kelvin terminal P14 of the first power device T11 and the first current change rate, the second stray inductances outside the first Kelvin terminal P13 and the second Kelvin terminal P14 of the first power device T11 can be determined. Similarly, the second stray inductances outside the first Kelvin terminal P23 and the second Kelvin terminal P24 of the second power device T12 can be determined.
[0036] If the first voltage and the second voltage are obtained during the same conduction phase of the power device, the first current change rate and the second current change rate are the same. If the first voltage and the second voltage are obtained during different conduction phases, the first current change rate and the second current change rate may be different, but this is not limited here.
[0037] S140. Determine the first target stray inductance of the power device based on the first stray inductance and the second stray inductance.
[0038] Specifically, for each power device, based on the first and second stray inductances of the same power device, the sum of the stray inductance between the first Kelvin terminal and the first terminal of the power device and the stray inductance between the second Kelvin terminal and the second terminal of the power device can be obtained. This sum yields the stray inductance of the power device in the power circuit, which is the first target stray inductance of the power device. Thus, the first target stray inductance of each power device can be determined.
[0039] By determining the sum of the stray inductance between the first Kelvin terminal and the first terminal of the power device T1 and the stray inductance between the second Kelvin terminal and the second terminal of the power device T1 as the first target stray inductance, excessive stray inductance of the power device can be avoided. For example, stray inductance from the connection between the power device and other circuits or loads can be avoided, further improving the accuracy of stray inductance determination of the power module under test.
[0040] S150. Determine the second target stray inductance of the power module under test based on the first target stray inductance of all power devices in the power module under test.
[0041] Specifically, after determining the first target stray inductance of each power device T1, the second target stray inductance of the power module under test 103 can be determined based on the first target stray inductance of all power devices T1 in the power module under test 103, thereby realizing the detection of the stray inductance of the power module.
[0042] The technical solution of this embodiment controls all power devices in the power module under test to be turned on. When all power devices are turned on, a first stray inductance is determined based on the first voltage between the first and second terminals of the power devices and the first current change rate of the power devices. A second stray inductance is determined based on the second voltage between the first and second Kelvin terminals of the power devices and the second current change rate of the power devices. A first target stray inductance of the power devices is determined based on the first and second stray inductances. A second target stray inductance of the power module under test is determined based on the first target stray inductances of all power devices in the power module under test. By controlling the turn-on or turn-off of the power module under test to detect the second target stray inductance of the power module under test, when the power module under test is turned on, both the energy storage module and the load module can discharge through the power module under test, resulting in a larger current flowing through the power module under test, a more obvious voltage plateau when the voltage of the power module under test is stable, and a more obvious current change rate of the power module under test, which can improve the accuracy of determining the stray inductance of the power module under test. Furthermore, by determining the sum of the stray inductance between the first Kelvin terminal and the first terminal of the power device and the stray inductance between the second Kelvin terminal and the second terminal of the power device as the first target stray inductance of the power device, excessive stray inductance of the power device can be avoided. For example, stray inductance between the power device and subsequent circuits can be avoided, thus achieving the effect of accurately determining the first target stray inductance of each power device and further improving the accuracy of stray inductance determination of the power module under test.
[0043] Based on the above technical solution, optionally, all power devices in the power module under test are controlled to be turned on, including: Step a1: Control all power devices in the power module under test to conduct for the first time.
[0044] Specifically, when all power devices T1 in the power module under test 103 are turned on for the first time, the energy storage module 101 discharges through the power module under test 130 and the load module 102 to charge the load module 102, so that electrical energy is stored in the load module 102.
[0045] Step a2: Turn off all power devices in the power module under test.
[0046] Specifically, the load module 102 can be connected to a freewheeling module, which may include diodes or MOSFET transistors, etc., without limitation. When all power devices T1 in the power module under test 103 are turned off, that is, during the intermittent phase, the load module 102 can continue current through the freewheeling module, thereby maintaining the current of the load module 102.
[0047] Step a3: Control all power devices in the power module under test to conduct for the second time.
[0048] Specifically, when all power devices T1 in the power module under test 103 are turned on for the second time, both the energy storage module 101 and the load module 120 discharge through the power module under test 103, resulting in a larger current through the power module under test 103. This makes the first current change rate and the second current change rate more obvious, thereby making the first voltage and the second voltage larger. This makes the voltage plateau when the voltage is stable more obvious, and it is easier to measure the first voltage, the first current change rate, the second voltage and the second current change rate. This improves the accuracy of determining the first stray inductance and the second stray inductance, and improves the accuracy of determining the second target stray inductance of the power module under test 103.
[0049] Based on the above technical solutions, Figure 4 This is a flowchart of another power module testing method provided in an embodiment of the present invention. Optionally, refer to... Figure 4 The testing methods for power modules include: S210, control all power devices in the power module under test to conduct for the first time.
[0050] S220: Turn off all power devices in the power module under test.
[0051] S230, control all power devices in the power module under test to conduct for the second time.
[0052] S240. The ratio of the difference between the third voltage and the first voltage between the first terminal and the second terminal of the energy storage module to the first current change rate is used as the first stray inductance.
[0053] Specifically, the third voltage is the voltage between the first terminal and the second terminal of the energy storage module 101 at the time corresponding to the first current change rate. Subtracting the first voltage from the third voltage yields the difference between the third voltage and the first voltage, which is the voltage outside the first terminal and the second terminal of the power device T1. Dividing the voltage outside the first terminal and the second terminal of the power device T1 by the first current change rate yields the ratio, which is the stray inductance outside the first terminal and the second terminal of the power device T1, i.e., the first stray inductance.
[0054] S250. The ratio of the difference between the fourth voltage and the second voltage between the first terminal and the second terminal of the energy storage module to the second current change rate is used as the second stray inductance.
[0055] Specifically, the fourth voltage is the voltage between the first terminal and the second terminal of the energy storage module 101 at the time corresponding to the second current change rate. Subtracting the second voltage from the fourth voltage yields the difference between the fourth and second voltages, which is the voltage outside the first Kelvin terminal and the second Kelvin terminal of the power device T1. Dividing the voltage outside the first Kelvin terminal and the second Kelvin terminal of the power device T1 by the second current change rate yields the stray inductance outside the first Kelvin terminal and the second Kelvin terminal of the power device T1, which is the second stray inductance.
[0056] S260. Determine the first target stray inductance of the power device based on the first stray inductance and the second stray inductance.
[0057] S270. Determine the second target stray inductance of the power module under test based on the first target stray inductance of all power devices in the power module under test.
[0058] Based on the above technical solution, optionally, the first target stray inductance of the power device is determined according to the first stray inductance and the second stray inductance, including: The difference between the second stray inductance and the first stray inductance is used as the first target stray inductance of the power device.
[0059] Specifically, for each power device T1, the stray inductance of the power device T1 is obtained by subtracting the corresponding first stray inductance from the second stray inductance. This yields the sum of the stray inductance between the first Kelvin terminal and the first terminal of the power device T1 and the stray inductance between the second Kelvin terminal and the second terminal of the power device T1. This sum is the stray inductance of the power device T1, which is the first target stray inductance.
[0060] Based on the above technical solutions, optionally, before determining the first stray inductance according to the first voltage between the first power terminal and the second power terminal of the power device and the first current change rate of the power device, the method further includes: Step b1: Determine the first initial current change rate at each sampling point when the power device is turned on for the second time.
[0061] Specifically, when the power device is turned on for the second time, the current of the power device is acquired at each sampling point, and the current change curve of the power device can be determined, thereby determining the first initial current change rate of the power device at each sampling point.
[0062] Step b2: Take the maximum value among all the first initial current change rates as the first current change rate.
[0063] Specifically, the maximum value among all the first initial current change rates in the current conduction phase (e.g., the second conduction phase) is taken as the first current change rate. Based on the first voltage and the third voltage at the time corresponding to the first current change rate, the first stray inductance corresponding to the power device can be determined.
[0064] The method for determining the second current change rate is the same as that for determining the first current change rate, and will not be repeated here.
[0065] The following describes the specific method for determining the first stray inductance based on the number of power devices that the power conversion circuit may include, but this is not intended to limit the scope of this application.
[0066] In one embodiment, the power module under test includes a substrate, and the power conversion circuit is located on the substrate, such as... Figure 2 As shown, the power conversion circuit 131 includes two power devices T1, namely a first power device T11 and a second power device T12. The first terminal P11 of the first power device T11 is connected to the load module 102. The second terminal P12 of the first power device T11 and the first terminal P21 of the second power device T12 are connected to a first connection point. The second terminal P22 of the second power device T12 is connected to the second terminal of the energy storage module 101. The first connection point is located on the substrate. The first connection point is the node where the power conversion circuit 131 outputs or inputs AC voltage. That is, the first connection point can be connected to other circuits or loads via a copper busbar.
[0067] For the first power device, the first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device, including: The first stray inductance of the first power device is determined based on the first voltage between the first terminal of the first power device and the first connection point and the first current change rate of the first power device.
[0068] Specifically, the first terminal P11 of the first power device T11 is connected to the load module 102, and the first terminal P11 of the first power device T11 is a power terminal. The difference between the third voltage between the first terminal and the second terminal of the energy storage module 101 and the first voltage of the first power device T11 is divided by the first current change rate of the first power device T11. The resulting ratio is the stray inductance other than the first terminal and the second terminal (first connection point) of the first power device T11, which is the first stray inductance of the first power device T11. In this way, stray inductance between the first connection point and the copper busbar connected to the first connection point (the second power terminal of the first power device T11) can be avoided, that is, stray inductance between the power device and other circuits or loads can be avoided, improving the accuracy of the determination of the first stray inductance, and facilitating the improvement of the accuracy of the determination of the second target stray inductance of the power module under test.
[0069] For the second power device, the first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device, including: The first stray inductance of the second power device is determined based on the first voltage between the second terminal of the second power device and the first connection point and the first current change rate of the second power device.
[0070] Specifically, the second terminal P2 of the second power device T12 is connected to the second terminal of the energy storage module 101, and the second terminal P2 of the second power device T12 is a power terminal. The difference between the third voltage between the first terminal and the second terminal of the energy storage module 101 and the first voltage of the second power device T12 is divided by the first current change rate of the second power device T12. The resulting ratio is the stray inductance between the first terminal (first connection point) of the second power device T12 and the second terminal of the second power device T12, which is the first stray inductance of the second power device T12. In this way, stray inductance between the first connection point and the copper busbar connected to the first connection point (the first power terminal of the second power device T12) can be avoided, that is, stray inductance from the connection of the power device with other circuits or loads can be avoided, improving the accuracy of the determination of the first stray inductance and facilitating the improvement of the accuracy of the determination of the stray inductance of the power module under test.
[0071] In another embodiment, the power conversion circuit 131 includes a power device T1; a first terminal of the power device T1 is connected to the load module 102, and a second terminal of the power device is connected to the second terminal of the energy storage module 101. The power conversion circuit 131 includes a power device T1, the first terminal of the power device T1 is a first power terminal of the power device T1, and the second terminal of the power device T1 is a second power terminal of the power device T1.
[0072] The first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device, including: The first stray inductance of the power device is determined based on the first voltage between the first power terminal and the second power terminal of the power device and the first current change rate of the power device.
[0073] Specifically, the difference between the third voltage and the first voltage between the first terminal and the second terminal of the energy storage module 101 is divided by the first current change rate, and the resulting ratio is the stray inductance outside the first terminal and the second terminal of the power device T1, which is the first stray inductance.
[0074] Based on the above technical solutions, Figure 5 This is a flowchart of another power module testing method provided in an embodiment of the present invention. Optionally, refer to... Figure 5 The testing methods for power modules include: S310: Controls all power devices in the power module under test to conduct for the first time.
[0075] S320: Control all power devices in the power module under test to turn off.
[0076] S330 controls all power devices in the power module under test to conduct for the second time.
[0077] S340. The ratio of the difference between the third voltage and the first voltage between the first terminal and the second terminal of the energy storage module to the first current change rate is used as the first stray inductance.
[0078] S350. The ratio of the difference between the fourth voltage and the second voltage between the first terminal and the second terminal of the energy storage module to the second current change rate is used as the second stray inductance.
[0079] S360. Determine the first target stray inductance of the power device based on the first stray inductance and the second stray inductance.
[0080] S370, the sum of the first target stray inductances of all power devices in the power module under test is taken as the second target stray inductance.
[0081] Specifically, after determining the first target stray inductance of each power device T1, the first target stray inductances of all power devices T1 in the power module under test 103 are added together to obtain the second target stray inductance of the power module under test 103.
[0082] This invention also provides a testing system for power modules. Figure 6 This is a circuit structure diagram of another power module test system provided in an embodiment of the present invention, for reference. Figure 6 The power module test system includes: energy storage module 101, load module 102, power module under test 103 and control module 104; The first end of the energy storage module 101 is connected to the first end of the external power supply 200, and the second end of the energy storage module 101 is connected to the second end of the external power supply 200; the load module 102 and the power under test module 103 are connected in series between the first end and the second end of the energy storage module 101; the power under test module 103 includes at least one power conversion circuit 131, and the power conversion circuit 131 includes at least one power device T1; The control module 104 is connected to the control terminal and the second Kelvin terminal of the power device T1. The control module 104 is used to execute the test method of the power module provided in any embodiment of the present invention.
[0083] Wherein, the first terminal of the external power supply 200 is a positive power supply voltage terminal, and the second terminal of the external power supply 200 is a negative power supply voltage terminal; or, the first terminal of the external power supply 200 is a negative power supply voltage terminal, and the second terminal of the external power supply 200 is a positive power supply voltage terminal, which is not limited here.
[0084] The control terminal of power device T1 is the gate of power device T1, the first Kelvin terminal of power device T1 is the drain of power device T1, and the second Kelvin terminal of power device T1 is the source of power device T1; or, the first Kelvin terminal of power device T1 is the source of power device T1, and the second Kelvin terminal of power device T1 is the drain of power device T1, which is not limited here.
[0085] The control module 104 is connected to the control terminal and the second Kelvin terminal of the power device T1, thereby controlling the voltage difference between the control terminal and the second Kelvin terminal of the power device T1, and thus controlling the power device T1 to be turned on or off.
[0086] The control module 104 may include a microcontroller, a digital signal processor (DSP), or a field programmable gate array (FPGA), etc., and is not limited to these components.
[0087] The control module 104 in the power module test system of this embodiment is used to execute the power module test method provided in any embodiment of the present invention. Therefore, the power module test system of this embodiment has the same beneficial effects as the power module test method provided in any embodiment of the present invention, and will not be described again here.
[0088] Figure 7 This is a circuit structure diagram of another power module testing system provided in an embodiment of the present invention. Optionally, refer to... Figure 7 The power module test system also includes a freewheeling module 105; The continuous current module 105 is connected in parallel with the load module 102.
[0089] The freewheeling module 105 may include a diode or a MOSFET transistor; no limitation is made herein. Figure 7 As shown, the freewheeling module 105 includes a freewheeling transistor T2, which can be a MOSFET transistor. The first terminal of the freewheeling transistor T2 is connected to the first terminal of the energy storage module 101, and the second terminal of the freewheeling transistor T2 is connected to the power module under test 103. The gate of the freewheeling transistor T2 is connected to the second terminal of the freewheeling transistor T2. The first terminal of the freewheeling transistor T2 is the drain, and the second terminal of the freewheeling transistor T2 is the source; or, the first terminal of the freewheeling transistor T2 is the source, and the second terminal of the freewheeling transistor T2 is the drain, which is not limited here.
[0090] Specifically, by setting up the freewheeling module 105, the load module 102 can continue current through the freewheeling module 105 when the power module under test 103 is turned off. For example... Figure 7 As shown, for example, load module 102 includes an inductor L1, and energy storage module 101 includes multiple first capacitors C1 connected in parallel.
[0091] 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.
[0092] 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 test method for a power module, characterized in that, The test is implemented by a power module testing system, which includes an energy storage module, a load module, and a power module under test. A first terminal of the energy storage module is connected to a first terminal of an external power supply, and a second terminal of the energy storage module is connected to a second terminal of the external power supply. The load module is connected in series with the power module under test between the first and second terminals of the energy storage module. The power module under test includes at least one power conversion circuit, and the power conversion circuit includes at least one power device. The method includes: All power devices in the power module under test are turned on. The first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device; wherein the first terminal and the second terminal of the power device are connected to a device other than the power device. The second stray inductance is determined based on the second voltage between the first Kelvin terminal and the second Kelvin terminal of the power device and the second current change rate of the power device; wherein the first Kelvin terminal of the power device is connected to the first terminal of the power device, and the second Kelvin terminal of the power device is connected to the second terminal of the power device. The first target stray inductance of the power device is determined based on the first stray inductance and the second stray inductance; The second target stray inductance of the power module under test is determined based on the first target stray inductance of all power devices in the power module under test.
2. The method according to claim 1, characterized in that, The control of all power devices in the power module under test to be turned on includes: The first turn-on of all power devices in the power module under test is controlled. All power devices in the power module under test are turned off. Control all power devices in the power module under test to conduct for the second time.
3. The method according to claim 1, characterized in that, The step of determining the first stray inductance based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device includes: The ratio of the difference between the third voltage and the first voltage between the first terminal and the second terminal of the energy storage module to the first current change rate is used as the first stray inductance. The second stray inductance is determined based on the second voltage between the first Kelvin terminal and the second Kelvin terminal of the power device and the second current change rate of the power device, including: The ratio of the difference between the fourth voltage and the second voltage between the first terminal and the second terminal of the energy storage module to the second current change rate is used as the second stray inductance.
4. The method according to claim 3, characterized in that, Determining the first target stray inductance of the power device based on the first stray inductance and the second stray inductance includes: The difference between the second stray inductance and the first stray inductance is used as the first target stray inductance of the power device.
5. The method according to claim 2, characterized in that, Before determining the first stray inductance based on the first voltage between the first power terminal and the second power terminal of the power device and the first current change rate of the power device, the method further includes: Determine the first initial current change rate at each sampling point when the power device is turned on for the second time; The maximum value among all the first initial current change rates is taken as the first current change rate.
6. The method according to any one of claims 1-5, characterized in that, The power module under test includes a substrate, and the power conversion circuit is located on the substrate. The power conversion circuit includes two power devices, namely a first power device and a second power device. The first terminal of the first power device is connected to the load module, and the second terminal of the first power device and the first terminal of the second power device are connected to a first connection point. The second terminal of the second power device is connected to the second end of the energy storage module. The first connection point is located on the substrate. For the first power device, determining the first stray inductance based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device includes: The first stray inductance of the first power device is determined based on the first voltage between the first terminal of the first power device and the first connection point and the first current change rate of the first power device. For the second power device, the first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device, including: The first stray inductance of the second power device is determined based on the first voltage between the second terminal of the second power device and the first connection point and the first current change rate of the second power device.
7. The method according to any one of claims 1-5, characterized in that, The power conversion circuit includes a power device; the first terminal of the power device is connected to the load module, and the second terminal of the power device is connected to the second terminal of the energy storage module. The first stray inductance is determined based on the first voltage between the first terminal and the second terminal of the power device and the first current change rate of the power device, including: The first stray inductance of the power device is determined based on the first voltage between the first power terminal and the second power terminal of the power device and the first current change rate of the power device.
8. The method according to any one of claims 1-5, characterized in that, Determining the second target stray inductance of the power module under test based on the first target stray inductance of all power devices in the power module under test includes: The sum of the first target stray inductances of all power devices in the power module under test is taken as the second target stray inductance.
9. A test system for a power module, characterized in that, include: Energy storage module, load module, power under test module, and control module; The first end of the energy storage module is connected to the first end of the external power supply, and the second end of the energy storage module is connected to the second end of the external power supply; the load module and the power under test module are connected in series between the first end and the second end of the energy storage module; the power under test module includes at least one power conversion circuit, and the power conversion circuit includes at least one power device. The control module is connected to the control terminal of the power device and the second Kelvin terminal of the power device, and the control module is used to execute the test method of the power module according to any one of claims 1-8.
10. The test system for the power module according to claim 9, characterized in that, The power module testing system also includes a freewheeling module; The continuous current module is connected in parallel with the load module.