Online double pulse test method and system based on electric control platform

Abstract

The application relates to the field of power electronics, and discloses an online double-pulse test method and system based on an electric control platform, which comprises the following steps: determining any power switch tube in a three-phase full-bridge power module as a measured switch tube; determining at least one accompanying switch tube and at least one auxiliary switch tube from the remaining power switch tubes according to the position of the measured switch tube in the three-phase full-bridge power module, and generating a corresponding on-off control strategy; controlling the on-off state of each power switch tube according to the on-off control strategy, using the equivalent inductance formed by the series connection of at least two phase windings in the motor stator winding as an inductive load, using a bus capacitor to provide a test voltage, and constructing a double-pulse test loop; applying a double-pulse signal to the control end of the measured switch tube, collecting voltage and / or current response signals in the double-pulse test loop, and extracting dynamic characteristic parameters of the measured switch tube according to the collected voltage and / or current response signals. The production line sampling test efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to an online double-pulse testing method and system based on an electronic control platform. Background Technology

[0002] Double-pulse testing is a core method for evaluating the switching characteristics, drive parameter matching, and stray inductance of power switching devices (such as IGBTs and MOSFETs). The test results are directly related to the reliability design and factory quality control of motor controllers (hereinafter referred to as EDCs).

[0003] Currently, the conventional procedure for double-pulse testing of three-phase full-bridge power modules in electronic control systems is as follows: the power module is removed from the electronic control unit, installed on a dedicated test bench, and equipped with low stray inductance busbars, bus capacitors, isolation gate drivers, and temperature control devices. A high-power air-core inductor or magnetic inductor is connected externally as an inductive load. The test is then completed using a double-pulse generator and an oscilloscope, after which the module is reinstalled into the entire unit. In addition, some testing solutions attempt to perform online testing directly at the system level. This involves short-circuiting the AC ports using external contactors and constructing a circuit using the converter's own filter inductor. Another solution proposes using a motor from the actual system as a load for on-site testing.

[0004] However, the existing methods described above still have the following objective drawbacks: 1. Disassembly and reassembly testing significantly impacts the reliability of modules and the entire system. Disassembly and reassembly of power modules involve multiple steps, including terminal fastening, heat sink bonding, thermal dielectric coating, and mechanical fixation. Repeated disassembly and reassembly can easily cause mechanical damage to the module, loose terminals, or poor heat dissipation contact, and in severe cases, even device failure. For encapsulated or integrated busbar-based electronic control structures, the disassembly process is even more difficult and can even be destructive.

[0005] 2. Low testing efficiency and long cycle time. In scenarios such as R&D debugging, production line sampling, incoming material inspection, and after-sales fault analysis, repeated disassembly and assembly and test bench setup consume a lot of labor and time costs, making it difficult to meet the needs of rapid evaluation. Even with online testing solutions, external shorting devices or external loads are still required, and the system complexity is not substantially reduced.

[0006] 3. While some existing solutions propose using a motor as a load, they fail to explain how to overcome the impact of nonlinear inductance caused by motor winding core saturation on test accuracy, nor do they provide systematic switching control logic for full-coverage testing of all six power switches in a three-phase full-bridge circuit. Furthermore, because the motor windings are simultaneously affected by rotor position and magnetic circuit saturation during actual operation, their equivalent inductance is not constant. Effective technical means to ensure the repeatability and consistency of double-pulse test parameters under these non-ideal conditions remain lacking.

[0007] 4. Differences exist between test conditions and real-world application environments. The busbar layout, stray inductance distribution, and bus capacitor configuration of the dedicated test bench do not entirely match the actual layout of the entire electronic control unit. Dynamic parameters such as switching voltage overshoot and switching losses of power switches are extremely sensitive to busbar stray inductance and drive circuits. Data measured on the test bench often cannot accurately reflect the module's true performance within the entire electronic control unit. Even with online testing, if the load circuit fails to accurately reproduce the actual operating current path, the measured dynamic parameters may still deviate from actual operating conditions, reducing the validity of the test results.

[0008] In view of this, in order to achieve comprehensive testing of the dynamic characteristics of each power switch in the three-phase full-bridge power module without disassembling the power module and without relying on an external dedicated load inductor, an implementation scheme that can utilize existing components of the power control system to construct a test circuit is required. Summary of the Invention

[0009] The technical problem that this invention aims to solve is: how to achieve comprehensive testing of the dynamic characteristics of each power switch in a three-phase full-bridge power module without disassembling the power module or relying on an external dedicated load inductor, while the motor controller is in its entirety.

[0010] In a first aspect, to solve the above-mentioned technical problems, an online dual-pulse testing method based on an electronic control platform is provided. The electronic control platform includes a three-phase full-bridge power module, a bus capacitor, and a motor stator winding. The method includes: Identify any one of the power switches in the three-phase full-bridge power module as the switch under test; Based on the position of the tested switch in the three-phase full-bridge power module, at least one companion switch and at least one auxiliary switch are determined from the remaining power switches, and a corresponding on / off control strategy is generated. The on / off state of each power switch is controlled according to the on / off control strategy. The equivalent inductance formed by at least two phases of the motor stator winding connected in series is used as an inductive load. The test voltage is provided by the bus capacitor to construct a double-pulse test circuit corresponding to the switch under test. A double-pulse signal is applied to the control terminal of the switch under test, and the voltage response signal and / or current response signal in the double-pulse test circuit are acquired. Based on the acquired voltage response signal and / or current response signal, the dynamic characteristic parameters of the switch under test are extracted.

[0011] Further, determining at least one companion switch and at least one auxiliary switch from the remaining power switches based on the position of the switch under test in the three-phase full-bridge power module includes: When the switch under test is the upper bridge arm switch, the lower bridge arm switch of the same phase is determined to be the accompanying switch, and at least one switch in other phases on a different side of the half-bridge arm where the switch under test is located is determined to be the auxiliary switch. When the switch under test is a lower bridge arm switch, the upper bridge arm switch of that phase is determined to be a companion switch, and at least one switch in other phases on a different side of the half-bridge arm where the switch under test is located is determined to be an auxiliary switch.

[0012] Further, controlling the on / off state of each power switch according to the on / off control strategy includes: The test switch is kept continuously turned on; The auxiliary switch tube used to connect the corresponding phase winding to the dual-pulse test circuit is kept on continuously; All other switching transistors except the one under test are kept off.

[0013] Furthermore, constructing the dual-pulse test circuit corresponding to the switch under test includes: The first current path, when the switch under test is turned on, the current flows sequentially through the bus capacitor, the switch under test, the equivalent inductance, and the auxiliary switch under test, forming an energy storage stage loop; The second current path, when the tested switch is turned off, the current freewheels through the equivalent inductance, the accompanying switch and its anti-parallel diode, forming a freewheeling stage loop; When the tested switch is turned on again, the anti-parallel diode of the accompanying switch undergoes a reverse recovery process.

[0014] Furthermore, the dynamic characteristic parameters include: At least one of the following: turn-on loss, turn-off loss, voltage overshoot, peak reverse recovery current, and reverse recovery loss; The switch under test has at least one of the following: turn-on delay, rise time, turn-off delay, and fall time.

[0015] Furthermore, the dual-pulse signal includes a first pulse, an interval period, and a second pulse, wherein: The first pulse is used to raise the current in the equivalent inductance to a preset test current value; The time interval is used to maintain the current in the equivalent inductance through the freewheeling path; The second pulse is used to test the turn-off characteristics of the switch under test and the reverse recovery characteristics of the corresponding anti-parallel diode.

[0016] Furthermore, the width of the first pulse is determined based on a preset test current value, bus voltage, and equivalent inductance value:

[0017] In the formula, The width of the first pulse; The preset test current value; The equivalent inductance value of the series connection of the two-phase windings connected to the dual-pulse test circuit; This is the bus voltage.

[0018] Furthermore, the method also includes sequentially performing the test method on multiple power switches in the three-phase full-bridge power module to perform a comprehensive test on each power switch in the three-phase full-bridge power module.

[0019] Furthermore, the power switching transistors in the three-phase full-bridge power module are IGBTs or MOSFETs; each of the power switching transistors is connected in anti-parallel with a freewheeling diode.

[0020] A second aspect of the present invention provides an online dual-pulse testing system based on an electronic control platform, the electronic control platform comprising a three-phase full-bridge power module, a bus capacitor, and a motor stator winding, the system comprising a control unit and a signal acquisition unit, wherein: The control unit executes the online double-pulse test method based on the electronic control platform, controls the on / off state of each power switch to construct a double-pulse test circuit, and applies a double-pulse signal to the switch under test; The signal acquisition unit acquires the voltage response signal and / or current response signal in the dual-pulse test circuit.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: This invention utilizes existing components of the electrical control platform to construct a dual-pulse test circuit in its entirety state (i.e., replacing the external dedicated load inductor with the two-phase series equivalent inductance in the motor stator winding, providing test energy with the bus capacitor, and achieving flexible reconfiguration of the test circuit through a preset switching combination strategy). Thus, dual-pulse testing can be completed online without disassembling the power module, eliminating the adverse effects of disassembly and assembly on the reliability of the module and the entire machine, and improving testing efficiency in scenarios such as production line sampling, incoming material inspection, and after-sales fault diagnosis.

[0022] Meanwhile, since the test circuit completely replicates the actual busbar layout, stray inductance distribution, bus capacitor configuration and drive circuit conditions of the entire electronic control unit, the measured dynamic characteristic parameters such as switching loss and voltage overshoot can truly reflect the performance of the power module under actual working conditions, effectively overcoming the inherent defects of traditional dedicated test benches that cause test data distortion due to differences in circuit conditions.

[0023] Furthermore, by controlling the on / off combinations of different switching transistors in the three-phase full-bridge, the dynamic characteristics of all six power switching transistors and their freewheeling diodes can be evaluated one by one, achieving comprehensive online testing of the power module performance of the entire power control unit without increasing external hardware costs. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a schematic diagram showing the on / off state configuration of each power switch and the corresponding current path when performing a double-pulse test on the lower bridge arm switch of the U phase, as disclosed in this invention.

[0026] Figure 2 This is a schematic diagram showing the on / off state configuration of each power switch and the corresponding current path when performing a double-pulse test on the lower bridge arm switch of phase V, as disclosed in this invention.

[0027] Figure 3 This is a schematic diagram showing the on / off state configuration of each power switch and the corresponding current path when performing a double-pulse test on the lower bridge arm switch of phase W, as disclosed in this invention.

[0028] Figure 4 The overall flowchart of the online dual-pulse testing method based on an electronic control platform provided by the present invention is shown below. Detailed Implementation

[0029] 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 are within the scope of protection of the present invention.

[0030] This invention aims to provide an online dual-pulse testing method based on an electronic control platform, with the test object being a three-phase full-bridge power module in a motor controller (i.e., electronic control unit). This three-phase full-bridge power module is commonly used in electric vehicle drive systems, industrial servo drive systems, or other motor control systems.

[0031] Those skilled in the art will understand that this three-phase full-bridge power module includes six power switching transistors, forming three bridge arms: U-phase, V-phase, and W-phase. Each bridge arm includes an upper bridge arm switch and a lower bridge arm switch, which are connected in series between the positive and negative terminals of the DC bus. One end of the upper bridge arm switch is connected to the positive terminal of the DC bus, and the other end is connected to the output terminal of that phase; one end of the lower bridge arm switch is connected to the output terminal of that phase, and the other end is connected to the negative terminal of the DC bus. The output terminal of each phase is connected to the corresponding phase winding of the motor.

[0032] For ease of description, the upper bridge arm switch of phase U is labeled Q1, the lower bridge arm switch of phase U is labeled Q2, the upper bridge arm switch of phase V is labeled Q3, the lower bridge arm switch of phase V is labeled Q4, the upper bridge arm switch of phase W is labeled Q5, and the lower bridge arm switch of phase W is labeled Q6. The stator winding of phase U is labeled L1, the stator winding of phase V is labeled L2, and the stator winding of phase W is labeled L3. The positive terminal of the bus capacitor is connected to the positive terminal of the DC bus, and the negative terminal of the bus capacitor is connected to the negative terminal of the DC bus. This is used to filter the DC bus voltage and provide the energy required for testing.

[0033] Each power switch is connected in reverse parallel with a freewheeling diode. This freewheeling diode can be the body diode of the power switch or a separate diode. When the corresponding power switch is turned off, this freewheeling diode provides a freewheeling path for the current in the inductive load.

[0034] The motor controller also includes a gate drive circuit, which drives each power switch to turn on or off according to the control signal output by the control unit. This gate drive circuit provides the necessary driving conditions for the implementation of the method of this application and requires no additional configuration.

[0035] See Figure 4 The online double-pulse testing method based on an electronic control platform provided in this application includes the following steps: S1: Identify the switch being tested.

[0036] Select one of the six power switches from the three-phase full-bridge power module as the switch under test according to the test requirements. The switch under test can be any one of the six power switches, such as the upper bridge arm switch Q1 of phase U, the lower bridge arm switch Q2 of phase U, the upper bridge arm switch Q3 of phase V, the lower bridge arm switch Q4 of phase V, the upper bridge arm switch Q5 of phase W, or the lower bridge arm switch Q6 of phase W.

[0037] In practical applications, the six power switches are usually tested in a preset order to achieve a comprehensive evaluation of each power switch in the three-phase full-bridge power module.

[0038] S2: Determine the test switch and auxiliary switch, and generate the corresponding on / off control strategy.

[0039] Based on the specific location of the tested switch in the three-phase full-bridge power module (i.e., which phase it belongs to and whether it belongs to the upper or lower bridge arm), at least one companion switch and at least one auxiliary switch are determined from the remaining power switches. The companion switch provides a current freewheeling path when the tested switch is turned off, and the auxiliary switch connects the corresponding phase winding to the dual-pulse test circuit. The on / off control strategy specifies whether each power switch should be in the on or off state throughout the test.

[0040] S3: The on / off control strategy controls the on / off state of each power switch to construct a dual-pulse test circuit.

[0041] This step utilizes the equivalent inductance formed by connecting at least two phases of the motor stator winding in series as an inductive load, and the test voltage is provided by the original bus capacitor in the electronic control platform. Thus, a double-pulse test circuit corresponding to the switch under test is constructed without the need for an external load inductor or the need to disassemble the power module.

[0042] S4: Apply a double-pulse signal to the control terminal of the switch under test and acquire the voltage and / or current signals in the double-pulse test circuit.

[0043] The dual-pulse signal consists of two pulses. The first pulse is used to raise the current in the equivalent inductance to a preset test current value, and the second pulse is used to test the turn-off characteristics of the switch under test and the reverse recovery characteristics of the corresponding freewheeling diode.

[0044] S5: Extract the dynamic characteristic parameters of the switch under test based on the collected voltage and / or current signals.

[0045] These dynamic characteristic parameters include, but are not limited to, turn-on loss, turn-off loss, voltage overshoot, peak reverse recovery current, reverse recovery loss, turn-on delay, rise time, turn-off delay, and fall time.

[0046] Figures 1 to 3 The diagram illustrates the on / off state configuration and corresponding current paths of each power switch during a double-pulse test of the lower bridge arm switches in phases U, V, and W. The following detailed explanation of each step in the above process is provided with reference to specific embodiments.

[0047] Example 1 1. Determining the switch to be tested like Figure 1As shown, the U-phase lower bridge arm switch Q2 is selected as the switch under test. In this embodiment, the switch under test Q2 is the power switch of the U-phase lower bridge arm, with one end connected to the U-phase output terminal (i.e., one end of the U-phase stator winding L1) and the other end connected to the negative terminal of the DC bus. After selecting the switch under test, it is necessary to determine the accompanying switch and auxiliary switch based on the position of the switch under test in the three-phase full-bridge power module, and generate the corresponding on / off control strategy.

[0048] exist Figure 1 In the illustrated embodiment, the U-phase lower bridge arm switch Q2 is the switch under test, the U-phase upper bridge arm switch Q1 is designated as the auxiliary switch under test, and the W-phase lower bridge arm switch Q6 is designated as the auxiliary switch. The on / off control strategy is as follows: the U-phase upper bridge arm switch Q1, the V-phase upper bridge arm switch Q3, the V-phase lower bridge arm switch Q4, and the W-phase upper bridge arm switch Q5 are controlled to be in the off state; the W-phase lower bridge arm switch Q6 is controlled to be continuously on; the U-phase lower bridge arm switch Q2 is controlled to receive the double-pulse signal as the switch under test; and the U-phase upper bridge arm switch Q1 is controlled to remain on as the auxiliary switch under test.

[0049] For ease of understanding, the states of each switch are summarized as follows: Q1 acts as the auxiliary switch under test, continuously conducting; Q2 acts as the switch under test, receiving the double-pulse signal; Q3 and Q5 are off; Q4 is off; and Q6 acts as the auxiliary switch, continuously conducting. The U-phase stator winding L1 and the V-phase stator winding L2 are connected in series, serving as the inductive load for the double-pulse test. It should be noted that the W-phase lower bridge arm switch Q6 is chosen as the auxiliary switch, ensuring that the current path, after connecting the U-phase winding L1 and the V-phase winding L2 in series, returns to the negative terminal of the bus capacitor via Q6, thus connecting the equivalent series inductance of L1 and L2 into the test circuit.

[0050] 2. Construction of the dual-pulse test circuit In this embodiment, after controlling the power switching transistors to turn on or off according to the above-described on / off control strategy, a double-pulse test circuit corresponding to the tested switching transistor Q2 can be constructed on the electronic control platform. This double-pulse test circuit specifically includes the following main paths: The first current path is the energy storage stage loop. When the tested switch Q2 is turned on, the current starts from the positive terminal of the bus capacitor, flows sequentially through the tested switch Q2, the U-phase stator winding L1, the V-phase stator winding L2, and the auxiliary switch Q6, and finally returns to the negative terminal of the bus capacitor. In this path, the bus capacitor releases electrical energy, and the current flows through the series equivalent inductance of the U-phase stator winding L1 and the V-phase stator winding L2. The current in the inductor rises linearly, and the electrical energy is stored in the motor windings in the form of magnetic field energy.

[0051] The second current path is the freewheeling phase loop. When the tested switch Q2 is turned off, since the inductor current cannot change abruptly, the current in the series equivalent inductance of the U-phase stator winding L1 and the V-phase stator winding L2 needs to be maintained through the freewheeling path. At this time, the current starts from the series equivalent inductance of the U-phase stator winding L1 and the V-phase stator winding L2, freewheels through the anti-parallel diode of the tested switch Q1, and forms a closed freewheeling loop. During the freewheeling process, the current in the inductor gradually decays, but the decay rate is slow, thus maintaining a basically constant current before the arrival of the second pulse.

[0052] When the tested switch Q2 turns on again, the anti-parallel diode of the auxiliary switch Q1 undergoes a reverse recovery process. At this time, the current flows from the positive terminal of the bus capacitor through the series equivalent inductance of the tested switch Q2, the U-phase stator winding L1 and the V-phase stator winding L2, and the auxiliary switch Q6 back to the negative terminal of the bus capacitor. Simultaneously, the anti-parallel diode of the auxiliary switch Q1 switches from the on state to the off state, generating a reverse recovery current.

[0053] 3. Apply double pulse signal and acquire response signal In this embodiment, after the dual-pulse test circuit is constructed, a dual-pulse signal is applied to the control terminal of the switch Q2 under test. This dual-pulse signal consists of three parts: a first pulse, an interval period, and a second pulse. Specifically: The first pulse has a first width. When the rising edge of the first pulse arrives, the tested switch Q2 turns on, and current flows from the bus capacitor through the tested switch Q2 into the series equivalent inductance of the U-phase stator winding L1 and the V-phase stator winding L2. The inductor current rises linearly from zero. The width of the first pulse is determined according to a preset test current value. When the inductor current rises to the preset test current value, the falling edge of the first pulse arrives, and the tested switch Q2 turns off. Specifically, the width of the first pulse needs to be determined according to the preset test current value. In the formula, The width of the first pulse; The preset test current value; The equivalent inductance value of the series connection of the two-phase windings connected to the dual-pulse test circuit; This is the bus voltage.

[0054] The interval is located between the first and second pulses. During the interval, the tested switch Q2 is in the off state, and the inductor current freewheels through the anti-parallel diode of the accompanying switch Q1. Due to the small resistance loss in the freewheeling circuit, the inductor current remains essentially constant during the interval. The length of the interval should be short enough that the inductor current does not decay excessively before the arrival of the second pulse.

[0055] The second pulse has a second width. This second width is typically smaller than the first width. The rising edge of the second pulse is used to trigger the observation of the reverse recovery process, and the falling edge is used to observe the turn-off characteristics of the switch under test. Specifically, the second pulse width only needs to ensure that a complete reverse recovery current waveform can be observed during the turn-on period of the switch under test; it is not necessary to cause a further significant increase in the inductor current. In practical applications, the second pulse width is generally set between several microseconds and tens of microseconds, with the specific value determined based on the type of power switch under test and its operating conditions.

[0056] During the application of the dual-pulse signal, the collector-emitter voltage and gate-emitter voltage signals of the transistor Q2 under test are acquired through a voltage probe, and the collector current signal of the transistor Q2 under test is acquired through a current probe. These voltage and current signals are input into an oscilloscope or data acquisition card for recording and storage.

[0057] 4. Extract dynamic characteristic parameters In this embodiment, based on these extracted dynamic characteristic parameters, the switching performance of the tested switch Q2 can be evaluated, the suitability of the drive parameters (such as the value of the gate resistor) can be determined, and it can be determined whether measures such as adding a snubber circuit are needed to suppress voltage overshoot.

[0058] Example 2 like Figure 2 As shown, the V-phase lower bridge arm switch Q4 is selected as the switch under test. In this embodiment, the switch under test Q4 is the power switch of the V-phase lower bridge arm, with one end connected to the V-phase output terminal (i.e., one end of the V-phase stator winding L2) and the other end connected to the negative terminal of the DC bus.

[0059] After selecting the switch to be tested, it is necessary to determine the accompanying switch and auxiliary switch based on the position of the switch to be tested in the three-phase full-bridge power module, and generate the corresponding on / off control strategy.

[0060] exist Figure 2 In the illustrated embodiment, the V-phase lower bridge arm switch Q4 is the switch under test, the V-phase upper bridge arm switch Q3 is designated as the auxiliary switch under test, and the U-phase upper bridge arm switch Q1 is designated as the auxiliary switch. The on / off control strategy is as follows: the V-phase upper bridge arm switch Q3, the U-phase upper bridge arm switch Q1, the W-phase upper bridge arm switch Q5, and the W-phase lower bridge arm switch Q6 are controlled to be in the off state; the U-phase lower bridge arm switch Q2 is controlled to be in the off state; the V-phase lower bridge arm switch Q4 is controlled to receive the double-pulse signal as the switch under test; and the V-phase upper bridge arm switch Q3 is controlled to remain in the on state as the auxiliary switch under test.

[0061] For ease of understanding, the states of each switch are summarized as follows: Q3 serves as the auxiliary switch under test and is continuously on; Q4 serves as the switch under test, receiving the double-pulse signal; Q1 is on and acts as an auxiliary switch; Q2 is off; Q5 is off; and Q6 is off. The V-phase stator winding L2 and the W-phase stator winding L3 are connected in series and together serve as the inductive load for the double-pulse test.

[0062] After controlling each power switch to be turned on or off according to the above on / off control strategy, a double-pulse test circuit corresponding to the switch Q4 under test can be constructed on the electronic control platform.

[0063] The dual-pulse test circuit specifically includes the following main paths: The first current path is the energy storage stage loop. When the tested switch Q4 is turned on, the current starts from the positive terminal of the bus capacitor, passes through the auxiliary switch Q1, the V-phase stator winding L2, the W-phase stator winding L3, the tested switch Q4, and finally returns to the negative terminal of the bus capacitor. In this path, the bus capacitor releases electrical energy, and the current flows through the series equivalent inductance of the V-phase stator winding L2 and the W-phase stator winding L3, with the current in the inductor increasing linearly.

[0064] The second current path is the freewheeling stage loop. When the tested switch Q4 is turned off, the current starts from the series equivalent inductance of the V-phase stator winding L2 and the W-phase stator winding L3, and freewheels through the anti-parallel diode of the tested switch Q3, forming a closed freewheeling loop.

[0065] When the tested switch Q4 turns on again, the anti-parallel diode of the accompanying switch Q3 undergoes a reverse recovery process. At the rising edge of the second pulse, the tested switch Q4 turns on, and the anti-parallel diode of the accompanying switch Q3 transitions from the on state to the off state, generating a reverse recovery current. By acquiring the waveform of this reverse recovery current, the performance of the anti-parallel diode of the accompanying switch Q3 can be evaluated.

[0066] Similar to the U-phase lower bridge arm test, during the application of a dual-pulse signal, the collector-emitter voltage and gate-emitter voltage signals of the tested switch Q4 are acquired using a voltage probe, and the collector current signal of the tested switch Q4 is acquired using a current probe. Based on the acquired voltage and current signals, the following dynamic characteristic parameters of the tested switch Q4 are extracted: turn-on loss, turn-off loss, voltage overshoot, peak reverse recovery current, reverse recovery loss, turn-on delay, rise time, turn-off delay, and fall time.

[0067] Example 3 like Figure 3As shown, the lower bridge arm switch Q6 of phase W is selected as the switch under test. In this embodiment, the switch under test Q6 is the power switch of the lower bridge arm of phase W, with one end connected to the output terminal of phase W (i.e., one end of the stator winding L3 of phase W) and the other end connected to the negative terminal of the DC bus.

[0068] After selecting the switch to be tested, it is necessary to determine the accompanying switch and auxiliary switch based on the position of the switch to be tested in the three-phase full-bridge power module, and generate the corresponding on / off control strategy.

[0069] exist Figure 3 In the illustrated embodiment, the lower bridge arm switch Q6 of phase W is the switch under test, the upper bridge arm switch Q5 of phase W is designated as the auxiliary switch under test, and the lower bridge arm switch Q4 of phase V is designated as the auxiliary switch. The on / off control strategy is as follows: the upper bridge arm switch Q5 of phase W, the upper bridge arm switch Q1 of phase U, the lower bridge arm switch Q2 of phase U, and the upper bridge arm switch Q3 of phase V are controlled to be in the off state; the lower bridge arm switch Q4 of phase V is controlled to be continuously on; the lower bridge arm switch Q6 of phase W is controlled to receive the double pulse signal as the switch under test; and the upper bridge arm switch Q5 of phase W is controlled to remain on as the auxiliary switch under test.

[0070] For ease of understanding, the states of each switch are summarized as follows: Q5 acts as the auxiliary switch under test and is continuously on; Q6 acts as the switch under test and receives the double-pulse signal; Q4 acts as the auxiliary switch and is continuously on; Q1 is off; Q2 is off; and Q3 is off. The U-phase stator winding L1 and the V-phase stator winding L2 are connected in series and together serve as the inductive load for the double-pulse test.

[0071] It should be noted that in this embodiment, the two-phase windings connected to the test circuit are the U-phase stator winding L1 and the V-phase stator winding L2. The current path starts from the positive terminal of the bus capacitor, passes through the auxiliary switch Q4, the U-phase stator winding L1, the V-phase stator winding L2, and the switch under test Q6, and returns to the negative terminal of the bus capacitor. The auxiliary switch Q5, connected in parallel with the switch under test, provides a freewheeling path during the freewheeling phase.

[0072] After controlling the power switches to turn on or off according to the above on / off control strategy, a double-pulse test circuit corresponding to the switch Q6 under test can be constructed on the electronic control platform. The energy storage stage path and freewheeling stage path of this double-pulse test circuit are similar to those of the U-phase and V-phase embodiments described above, and will not be repeated here.

[0073] The three embodiments described above illustrate specific implementation methods using the lower bridge arm switches of phases U, V, and W as the switches under test. Testing the upper bridge arm switches can be performed using the same principle, by adjusting the on / off states of each power switch accordingly.

[0074] Taking the upper bridge arm switch Q1 of phase U as the switch under test, the control strategy is as follows: The lower bridge arm switch Q2 of phase U is designated as the companion switch, and the upper bridge arm switch Q3 of phase V or the upper bridge arm switch Q5 of phase W is designated as the auxiliary switch. The companion switch Q2 is kept continuously on, the auxiliary switch (such as Q3) is kept continuously on, and all other switches except the switch under test Q1 are kept continuously off. In this way, the series equivalent inductance of the stator winding L1 of phase U and the stator winding L2 of phase V can be used as an inductive load, with the bus capacitor providing the test voltage, thus constructing a double-pulse test circuit corresponding to the switch under test Q1.

[0075] When the upper bridge arm switch Q3 of phase V is the switch under test, the lower bridge arm switch Q4 of phase V is determined as the accompanying switch, and the upper bridge arm switch Q5 of phase W or the upper bridge arm switch Q1 of phase U is determined as the auxiliary switch. The double pulse test circuit is constructed according to the same principle.

[0076] When the upper bridge arm switch Q5 of phase W is the switch under test, the lower bridge arm switch Q6 of phase W is determined as the accompanying switch, and the upper bridge arm switch Q1 of phase U or the upper bridge arm switch Q3 of phase V is determined as the auxiliary switch. The double pulse test circuit is constructed according to the same principle.

[0077] Therefore, the test method provided in this application can cover all six power switching transistors in a three-phase full-bridge power module, realizing comprehensive online testing of all power switching transistors in the entire power control unit without disassembling the power module or relying on an external dedicated load inductor.

[0078] In practical applications, it is usually necessary to test multiple power switches in a three-phase full-bridge power module individually to comprehensively evaluate the dynamic characteristics of the power module. The test method provided in this application supports sequential, comprehensive testing of six power switches.

[0079] Specifically, the first test transistor is determined from the six power switching transistors according to the preset test sequence. The test sequence can be U-phase upper arm → U-phase lower arm → V-phase upper arm → V-phase lower arm → W-phase upper arm → W-phase lower arm, or any other arbitrary sequence, such as testing the upper arm first and then the lower arm in the order of U-phase → V-phase → W-phase.

[0080] Then, a complete double-pulse test is performed on the current switch under test, including identifying the companion switch and auxiliary switch, generating the on / off control strategy, controlling each power switch according to the on / off control strategy, constructing the double-pulse test circuit, applying the double-pulse signal, acquiring voltage and current signals, and extracting dynamic characteristic parameters.

[0081] After the current switch under test is tested, the test data is stored, and then the process is repeated for the next switch under test until all six power switches have been tested.

[0082] When switching between different power switches under test, the on / off states of each power switch need to be reconfigured to construct a dual-pulse test circuit corresponding to the new power switch under test. This reconfiguration process does not require changes to the physical connections; it can be achieved simply by updating the control signals of each power switch through the control unit. Therefore, the switching speed is fast and the operation is simple.

[0083] In practical applications, in order to verify the reliability of the power module, the above-mentioned comprehensive test can be repeated under different bus voltages, different test currents, and different temperatures to obtain the dynamic characteristic parameter variation law of the power switch under different operating conditions.

[0084] Furthermore, this invention also provides an online dual-pulse test system based on an electronic control platform. The electronic control platform includes a three-phase full-bridge power module, bus capacitors, and motor stator windings. The system includes a control unit and a signal acquisition unit. The control unit executes the aforementioned online dual-pulse test method based on the electronic control platform, controlling the on / off states of each power switch to construct a dual-pulse test circuit and applying a dual-pulse signal to the switch under test. The signal acquisition unit acquires the voltage response signal and / or current response signal in the dual-pulse test circuit.

[0085] As can be seen, the method provided by this invention utilizes the three-phase full-bridge power module, bus capacitor, and motor stator winding of the electronic control platform to construct a dual-pulse test circuit. It eliminates the need to disassemble the power module, connect an external load inductor, or use an external short-circuit device; dual-pulse testing is achieved simply by controlling the on / off state of each power switch. This method offers advantages such as high testing efficiency, low cost, and test results that closely reflect real-world application conditions.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for online dual-pulse testing based on an electronic control platform, wherein the electronic control platform includes a three-phase full-bridge power module, a bus capacitor, and a motor stator winding, characterized in that, The method includes: Identify any one of the power switches in the three-phase full-bridge power module as the switch under test; Based on the position of the tested switch in the three-phase full-bridge power module, at least one companion switch and at least one auxiliary switch are determined from the remaining power switches, and a corresponding on / off control strategy is generated. The on / off state of each power switch is controlled according to the on / off control strategy. The equivalent inductance formed by at least two phases of the motor stator winding connected in series is used as an inductive load. The test voltage is provided by the bus capacitor to construct a double-pulse test circuit corresponding to the switch under test. A double-pulse signal is applied to the control terminal of the switch under test, and the voltage response signal and / or current response signal in the double-pulse test circuit are acquired. Based on the acquired voltage response signal and / or current response signal, the dynamic characteristic parameters of the switch under test are extracted.

2. The online double-pulse testing method based on an electronic control platform according to claim 1, characterized in that, The step of determining at least one companion switch and at least one auxiliary switch from the remaining power switches based on the position of the switch under test in the three-phase full-bridge power module includes: When the switch under test is the upper bridge arm switch, the lower bridge arm switch of the same phase is determined to be the accompanying switch, and at least one switch in other phases on a different side of the half-bridge arm where the switch under test is located is determined to be the auxiliary switch. When the switch under test is a lower bridge arm switch, the upper bridge arm switch of that phase is determined to be a companion switch, and at least one switch in other phases on a different side of the half-bridge arm where the switch under test is located is determined to be an auxiliary switch.

3. The online double-pulse testing method based on an electronic control platform according to claim 1, characterized in that, The control of the on / off state of each power switch according to the on / off control strategy includes: The test switch is kept continuously turned on; The auxiliary switch tube used to connect the corresponding phase winding to the dual-pulse test circuit is kept on continuously; All other switching transistors except the one under test are kept off.

4. The online double-pulse testing method based on an electronic control platform according to claim 1, characterized in that, The construction of the dual-pulse test circuit corresponding to the switch under test includes: The first current path, when the switch under test is turned on, the current flows sequentially through the bus capacitor, the switch under test, the equivalent inductance, and the auxiliary switch under test, forming an energy storage stage loop; The second current path, when the tested switch is turned off, the current freewheels through the equivalent inductance, the accompanying switch and its anti-parallel diode, forming a freewheeling stage loop; When the tested switch is turned on again, the anti-parallel diode of the accompanying switch undergoes a reverse recovery process.

5. The online double-pulse testing method based on an electronic control platform according to claim 1, characterized in that, The dynamic characteristic parameters include: At least one of the following: turn-on loss, turn-off loss, voltage overshoot, peak reverse recovery current, and reverse recovery loss; The switch under test has at least one of the following: turn-on delay, rise time, turn-off delay, and fall time.

6. The online double-pulse testing method based on an electronic control platform according to claim 1, characterized in that, The dual-pulse signal includes a first pulse, an interval period, and a second pulse, wherein: The first pulse is used to raise the current in the equivalent inductance to a preset test current value; The time interval is used to maintain the current in the equivalent inductance through the freewheeling path; The second pulse is used to test the turn-off characteristics of the switch under test and the reverse recovery characteristics of the corresponding anti-parallel diode.

7. The online double-pulse testing method based on an electronic control platform according to claim 6, characterized in that, The width of the first pulse is determined based on the preset test current value, bus voltage, and equivalent inductance value: In the formula, The width of the first pulse; The preset test current value; The equivalent inductance value of the series connection of the two-phase windings connected to the dual-pulse test circuit; This is the bus voltage.

8. The online double-pulse testing method based on an electronic control platform according to claim 1, characterized in that, It also includes sequentially performing the test method on multiple power switches in the three-phase full-bridge power module to perform a comprehensive test on each power switch in the three-phase full-bridge power module.

9. The online double-pulse testing method based on an electronic control platform according to claim 1, characterized in that, The power switching transistors in the three-phase full-bridge power module are IGBTs or MOSFETs; each of the power switching transistors is connected in anti-parallel with a freewheeling diode.

10. An online dual-pulse testing system based on an electronic control platform, wherein the electronic control platform includes a three-phase full-bridge power module, a bus capacitor, and a motor stator winding, characterized in that, The system includes a control unit and a signal acquisition unit, wherein: The control unit executes the online double-pulse test method based on the electronic control platform as described in any one of claims 1 to 9, controls the on / off state of each of the power switching transistors to construct a double-pulse test circuit, and applies a double-pulse signal to the switching transistor under test; The signal acquisition unit acquires the voltage response signal and / or current response signal in the dual-pulse test circuit.

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