Method and system for simulating electrical stress of a port of an electric drive system of a power module under test

Abstract

The application discloses a power module test-oriented electrical stress simulation method and system for an electric drive system port, comprising: constructing a reference simulation model, outputting a target port current reference signal, a target port voltage reference signal and reference loss data of a power module to be tested; configuring an equivalent common DC bus, a host converter, a slave converter and a filter network to form a pair of drag test circuits; inputting the reference signal into the host converter and the slave converter, and combining the filter network matched with stator parameters to form an equivalent test port; setting the power module to be tested in a power main circuit of a power stage of the host converter, and sequentially calling the reference signal to carry out working condition simulation test; extracting on-off states and collecting port electrical parameters to input into a power module loss model, calculating actual loss data for each on-off period, comparing the actual loss data with the reference loss data to obtain loss evaluation results, so as to effectively overcome the defects of simulation and actual measurement misplacement, insufficient port equivalent accuracy and lack of quantitative evaluation closed loop.

Description

Technical Field

[0001] This invention relates to the field of testing technology for power modules under test in electric drive systems, and more specifically, to a method and system for simulating port electrical stress of electric drive systems for power modules under test. Background Technology

[0002] In the electric drive system of new energy vehicles, the reliability of power semiconductor modules directly determines the system lifespan. During actual vehicle operation, the electric drive system frequently experiences heavy-load starts, constant-speed cruising, deceleration braking, and energy recovery, leading to continuous changes in inverter port voltage, phase current, DC bus voltage, and switching states. This, in turn, causes conduction losses, switching losses, and junction temperature fluctuations in the power module under test. Alternating thermal stress driven by electrical stress is a major cause of solder layer fatigue, bond wire degradation, and package failure in the power module under test. Therefore, accurately reproducing the port electrical stress acting on the power module under test under the target electric drive system's operating conditions in a laboratory environment is a prerequisite for conducting loss consistency analysis, thermal stress assessment, and reliability verification.

[0003] However, existing electric drive system operating condition simulation schemes still have the following shortcomings: Firstly, most studies focus on motor simulation, power cycling, or control function verification, without directly linking the port voltage, port current, DC bus voltage, and their time-domain variation patterns under the target electric drive system's task conditions with the consistency of the power module losses under test. Secondly, the AC side filter network is mostly configured according to conventional filtering requirements, and no parameter correspondence is established with the equivalent inductance and stator resistance of the target motor stator. This causes a deviation between the voltage equation of the host converter port and the voltage equation of the target electric drive system port, weakening the equivalent accuracy of the port electrical boundary. Third, it is impossible to quantitatively assess the accuracy of the towing platform in reproducing the target working conditions, and it is also difficult to feed the evaluation results back to reliability testing and thermal design verification.

[0004] Based on this, this application proposes a method and system for simulating port electrical stress of electric drive systems for power modules under test. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing electric drive system operating condition simulation schemes, which often focus on motor simulation, power cycling, or control function verification. These schemes fail to directly correlate the simulated port voltage, simulated port current, DC bus voltage, and their time-domain variation patterns under the target electric drive system's task operating conditions with the consistency of the power module losses under test, resulting in misalignment of the target. Furthermore, the AC side filter networks are often configured according to conventional filtering requirements, without establishing a parameter correspondence with the equivalent inductance and stator resistance of the target motor stator. This leads to deviations in the simulated port voltage equations between the host converter and the target electric drive system, resulting in insufficient equivalent accuracy of the port electrical boundaries. Additionally, the invention fails to quantitatively assess the accuracy of the towing platform in reproducing the target operating conditions and makes it difficult to feed the evaluation results back to reliability testing and thermal design verification, lacking a quantitative evaluation closed loop.

[0006] To achieve the above objectives, the present invention provides a method and system for simulating port electrical stress of an electric drive system for a power module under test.

[0007] According to a first aspect of the present invention, a method for simulating port electrical stress of an electric drive system for a power module under test is provided, the electric drive system including an inverter having a power module, and a DC bus connected to its DC side and a motor connected to its AC side; Methods for simulating electrical stress at the ports of electric drive systems include: Based on the preset target electric drive system's motor parameters, inverter parameters, DC bus voltage, and task operating condition information, a benchmark simulation model is constructed and the target port current reference signal, target port voltage reference signal, and the benchmark loss data of the power module under test are output. A common DC bus with voltage equivalent to the DC bus voltage is configured, and a main converter and a slave converter with DC sides connected to the common DC bus, and a filter network connected between the AC sides of the main converter and the slave converter are combined to form a drag test circuit. The target port current reference signal and the target port voltage reference signal are input to the master converter and the slave converter respectively, so as to output the actual port current and the target port voltage boundary. Combined with the pre-established filter network including the correspondence between the filter inductor and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the master converter. The power module under test is set in the main power circuit of the host converter, and the test port is defined as the electrical stress reproduction port. By calling the target port current reference signal and the target port voltage reference signal in sequence on the drag test circuit, the port electrical stress corresponding to the target electric drive system is reproduced on the power module under test and the operating condition simulation test is performed. The real-time on / off status of the power module under test is continuously extracted, and the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port are collected simultaneously. A predefined power module loss model is input, and the actual loss data of the power module under test corresponding to all on / off cycles is calculated and output for each on / off cycle. The actual loss data of the power module under test is compared with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

[0008] Optionally, the step of constructing a benchmark simulation model based on the preset target electric drive system's motor parameters, inverter parameters, DC bus voltage, and task operating condition information, and outputting the target port current reference signal, target port voltage reference signal, and benchmark loss data of the power module under test, specifically includes: Based on the inherent hardware parameters of the target electric drive system and the actual vehicle operation conditions, the motor parameters, inverter parameters, DC bus voltage, and task condition information of the target electric drive system are preset. Among them, the DC bus voltage represents the operating voltage of the inverter on the DC side; the task condition information includes several task condition stages and corresponding timing, speed status data, and load torque. The motor model and inverter model are called to build a benchmark simulation model on the simulation platform. The motor parameters, inverter parameters, DC bus voltage and task operating condition information are input to perform simulation calculations. Combined with the thermoelectric joint loss simulation model and the thermal network model, the target port current reference signal, the target port voltage reference signal and the benchmark loss data of the power module under test are output.

[0009] Optionally, the process involves calling the motor model and inverter model, building a benchmark simulation model on the simulation platform, and inputting motor parameters, inverter parameters, DC bus voltage, and task operating condition information to perform simulation calculations. This is done in conjunction with the thermoelectric combined loss simulation model and the thermal network model to output the target port current reference signal, the target port voltage reference signal, and the benchmark loss data of the power module under test. Specifically, this includes: A benchmark simulation model is built on the Simulink or PLECS simulation platform based on the motor model, the inverter modulation model and the DC bus voltage constraint. Input preset motor parameters, inverter parameters, DC bus voltage and task operating condition information into the reference simulation model and perform simulation calculations to output stator three-phase current waveform and back EMF waveform based on the motor model side, and output inverter switching state, simulation port voltage and simulation port current based on the inverter modulation model side. The stator three-phase current waveform is extracted and defined as the target port current reference signal, and the back electromotive force waveform is extracted and defined as the target port voltage reference signal; The simulated port voltage, simulated port current, and inverter switching state are input into the thermoelectric joint loss simulation model to calculate the conduction loss and switching loss of several power devices in the power module under test based on the pre-acquired conduction characteristic parameters and switching characteristic parameters of the power devices. The conduction loss and switching loss are input into the thermal network model to perform feedback correction, so as to output the reference loss data of the power module under test.

[0010] Optionally, the configuration includes a common DC bus equivalent to the DC bus voltage, combined with a master converter and a slave converter whose DC sides are both connected to the common DC bus, and a filter network connected between the AC sides of the master converter and the slave converter to form a reverse-drive test circuit, specifically including: Configure a common DC bus and set the voltage of the common DC bus to be equal to the DC bus voltage of the target electric drive system; Configure a master converter and a slave converter, and connect the DC side of both the master converter and the slave converter to a common DC bus; An LCL filter is connected between the AC sides of the master converter and the slave converter to form a reverse-drive test circuit.

[0011] Optionally, the target port current reference signal and target port voltage reference signal are input to the master converter and slave converter respectively to output the actual port current and target port voltage boundaries. Combined with a pre-established filter network including the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the master converter. Specifically, this includes: Input the target port current reference signal into the main converter to output the actual port current; Input the target port voltage reference signal into the slave converter to output the target port voltage boundary; An LCL filter, which includes the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, is invoked. The actual port current and the target port voltage boundary are applied to both ends of the LCL filter to form a test port on the AC side of the main converter that is equivalent to the port electrical constraints of the reference simulation model.

[0012] Optionally, the step of setting the power module under test in the main power circuit of the host converter and defining the test port as the electrical stress reproduction port, and reproducing the port electrical stress corresponding to the target electric drive system on the power module under test and performing operating condition simulation test by sequentially calling the target port current reference signal and the target port voltage reference signal on the drive test circuit, specifically includes: The power module under test is set in the main power circuit of the main converter, and the test port is defined as the electrical stress reproduction port. The test circuit is called sequentially according to the simulation time axis of the target port current reference signal, and the actual output current of the AC side of the main converter is collected. Closed-loop regulation is performed based on the difference between the target port current reference signal and the actual output current to output the actual port current in real time. The test circuit is called sequentially according to the simulation time axis of the target port voltage reference signal, and the three-phase actual voltage of the filter capacitor port of the LCL filter and the three-phase current of the AC side of the slave converter are collected. Based on the target port voltage reference signal, the three-phase actual voltage and three-phase current are adjusted in a closed loop to output the target port voltage boundary in real time. The actual port current and target port voltage boundary are applied to both ends of the LCL filter in real time to reproduce the port electrical stress corresponding to the target electric drive system on the power module under test and perform operating condition simulation test.

[0013] Optionally, the test circuit performs a time-sequential call to the target port current reference signal based on the simulation time axis, and collects the actual output current on the AC side of the main converter. It then performs closed-loop regulation based on the difference between the target port current reference signal and the actual output current to output the actual port current in real time. Specifically, this includes: The test circuit is called sequentially according to the simulation time axis of the target port current reference signal; Collect the actual output current on the AC side of the main converter; The phase angle of the target electric drive system is obtained using a PLL, and Clarke and Park transformations are sequentially performed on the actual output current to convert it into... Rotating coordinate system The actual current components of the shaft and Actual current component of the shaft; The target port current reference signal of the time-sequential call is converted to To obtain in a rotated coordinate system Shaft current reference components and Shaft current reference component; calculate The actual current component of the shaft and Axis current reference component, and The actual current component of the shaft and The difference between the shaft current reference components is obtained. Shaft current error and Shaft current error; Will Shaft current error and The shaft current error is input to the corresponding PI controller to obtain... The main converter in the rotating coordinate system Shaft reference voltage signal and Shaft reference voltage signal; right Shaft reference voltage signal and The shaft reference voltage signal is sequentially subjected to inverse Park transform and inverse Clarke transform, and then input into the PWM modulation module to generate a drive signal, which controls the on / off state of the power module under test in the main power circuit of the host converter to output the actual port current.

[0014] Optionally, the test circuit performs time-sequential calls based on the simulation time axis of the target port voltage reference signal, and acquires the three-phase actual voltage at the filter capacitor port of the LCL filter and the three-phase current on the AC side of the slave converter. Based on the target port voltage reference signal, it performs closed-loop regulation on the three-phase actual voltage and three-phase current to output the target port voltage boundary in real time, specifically including: The test circuit is called sequentially according to the simulation time axis of the target port voltage reference signal; The actual three-phase voltage at the filter capacitor port of the LCL filter and the three-phase current on the AC side of the slave converter are collected. Based on the phase angle, Clarke and Park transformations are sequentially performed on the actual three-phase voltages and currents, and then converted to... Rotating coordinate system Actual voltage components of the shaft and The actual voltage component of the shaft, and Axis current components and Axis current components; The target port voltage reference signal called sequentially is converted to To obtain in a rotated coordinate system Shaft voltage reference components and Shaft voltage reference component, and corresponding calculation. Actual voltage components of the shaft and The difference between the actual voltage components of the shaft is obtained. Shaft voltage error and Shaft voltage error; Will Shaft voltage error and The PI controller corresponding to the shaft voltage error input outputs... Shaft current reference components and The shaft current reference component is calculated accordingly. Axis current components and The difference between the shaft current components is obtained. Shaft current error and Shaft current error; Will Shaft current error and The shaft current error is input to the corresponding PI controller to obtain... Slave converter in rotating coordinate system Shaft reference voltage signal and Shaft reference voltage signal; right Shaft reference voltage signal and The shaft reference voltage signal undergoes inverse Park transform and inverse Clarke transform sequentially, and is input into the PWM modulation module to generate drive signals, controlling the on / off switching of the power module in the slave converter to output the target port voltage boundary.

[0015] Optionally, the real-time on / off state of the power module under test is continuously extracted, and the current port voltage, current port current, and current DC bus voltage of the electrical stress reproduction port are simultaneously collected. A predefined power module loss model is input, and the actual loss data of the power module under test corresponding to all on / off cycles is calculated and output. The actual loss data of the power module under test is compared with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test, specifically including: Based on the preset sampling frequency, the real-time on / off status of the power module under test is continuously extracted, and the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port are collected simultaneously. The current port voltage, current port current and current DC bus voltage are low-pass filtered, and the predefined power module loss model is input in combination with the real-time on / off state of the power module under test. Based on the sampling timing of each on / off cycle, the conduction loss and switching loss of each power device in the power module under test are calculated and accumulated for each on / off cycle to obtain the total device loss corresponding to each on / off cycle. The on / off cycle is the time period for each power device to perform one on / off switching. Match the total device loss corresponding to each on / off cycle with each task condition stage in the task condition information to obtain the actual loss data of the power module under test. The actual loss data of the power module under test is compared with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

[0016] According to a second aspect of the present invention, an electric drive system port electrical stress simulation system for a power under test module is also provided, for implementing the electric drive system port electrical stress simulation method for a power under test module as described in any of the preceding claims, the electric drive system port electrical stress simulation system comprising: The benchmark data acquisition module is used to construct a benchmark simulation model and output the target port current reference signal, the target port voltage reference signal and the benchmark loss data of the power module under test based on the preset target electric drive system's motor parameters, inverter parameters, DC bus voltage and task operating condition information. A test circuit module is formed by configuring a common DC bus equivalent to the DC bus voltage, and combining a master converter and a slave converter whose DC sides are both connected to the common DC bus, and a filter network connected between the AC sides of the master converter and the slave converter to form a test circuit. The test port forming module can input the target port current reference signal and the target port voltage reference signal into the master converter and the slave converter respectively, so as to output the actual port current and target port voltage boundary. Combined with the pre-established filter network including the correspondence between the filter inductor and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the master converter. The simulation execution module can set the power module under test in the power main circuit of the host converter and define the test port as the electrical stress reproduction port. By calling the target port current reference signal and the target port voltage reference signal in sequence on the drag test circuit, the electrical stress of the port corresponding to the target electric drive system can be reproduced on the power module under test and the operating condition simulation test can be performed. The evaluation result acquisition module is used to continuously extract the real-time on / off status of the power module under test, and simultaneously collect the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port. It inputs a predefined power module loss model, calculates and outputs the actual loss data of the power module under test for each on / off cycle, and compares the actual loss data of the power module under test with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention proposes a method for simulating the electrical stress at the ports of an electric drive system for power modules under test. It constructs a benchmark simulation model by pre-setting the motor parameters, inverter parameters, DC bus voltage, and task operating conditions of the target electric drive system. The model outputs a target port current reference signal, a target port voltage reference signal, and benchmark loss data for the power module under test, thus directly correlating the time-domain variation patterns of the simulated port voltage, simulated port current, and DC bus voltage with the benchmark loss data of the power module under test. Furthermore, it constructs a test circuit by configuring a common DC bus, a master converter, a slave converter, and a filter network that includes the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and stator resistance. This ensures that the parameters of the filter network correspond to the parameters of the motor's stator equivalent inductance and stator resistance, eliminating the deviation between the master converter and the simulated port voltage constraints of the target electric drive system. Finally, it uses the target port current reference signal and the target port voltage reference signal... The input signals are respectively input to the host converter and the slave converter to form a test port that is equivalent to the electrical constraints of the reference simulation model port, thereby improving the equivalent accuracy of the electrical boundary of the test port. Furthermore, by setting the power module under test in the power main circuit of the host converter and defining the test port as the electrical stress reproduction port, the operating condition simulation test is carried out by sequentially calling the target port current reference signal and the target port voltage reference signal of the drag test circuit. Simultaneously, the electrical parameters of the electrical stress reproduction port are collected, the real-time on / off state of the power module under test is extracted and input into the predefined power module loss model, the actual loss data of the power module under test is calculated, and the loss evaluation result is obtained by comparing it with the reference loss data of the power module under test. This realizes the quantitative evaluation of the task operating condition reproduction accuracy of the drag test circuit, completes the quantitative evaluation closed loop that can be used for reliability testing and thermal design verification, and effectively overcomes the defects of simulation and actual reproduction misalignment, insufficient port equivalent accuracy, and lack of quantitative evaluation closed loop.

[0018] The electrical stress simulation system for the electric drive system port of the power under test module proposed in this invention belongs to the same general inventive concept as the electrical stress simulation method for the electric drive system port of the power under test module of this invention. It should at least have the same technical effect as the electrical stress simulation method for the electric drive system port of the power under test module of this invention. Therefore, this invention will not elaborate further here.

[0019] As can be seen from the above, the technical solution of this invention can effectively solve the problems of existing electric drive system operating condition simulation schemes, which mostly focus on motor simulation, power cycle, or control function verification, and fail to directly correlate the simulation port voltage, simulation port current, DC bus voltage and their time-domain variation law under the target electric drive system's task operating condition with the consistency of the power module loss under test, resulting in misalignment of the target reproduction; AC side filter networks are mostly configured according to conventional filter requirements, and no parameter correspondence is established with the equivalent inductance and stator resistance of the target motor stator, resulting in deviations between the simulation port voltage equations of the host converter and the target electric drive system, and insufficient equivalent accuracy of the port electrical boundary; it is impossible to quantitatively evaluate the reproduction accuracy of the towing platform for the target operating condition, and it is also difficult to feed the evaluation results back to reliability testing and thermal design verification, lacking a quantitative evaluation closed loop.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the method for simulating port electrical stress of an electric drive system for a power module under test, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the topology of the drag test circuit according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a port electrical stress simulation system for an electric drive system of a power module under test, according to an embodiment of the present invention.

[0022] Figure label: 100 - Common DC bus; 200 - Main converter; 300 - Slave converter; 400 - LCL filter. Detailed Implementation

[0023] To enable those skilled in the art to more fully understand the technical solutions of the present invention, exemplary embodiments of the present invention will be described more comprehensively and in detail below with reference to the accompanying drawings. Obviously, the one or more embodiments of the present invention described below are merely one or more specific ways to implement the technical solutions of the present invention, and are not exhaustive. It should be understood that other ways belonging to a general inventive concept can be used to implement the technical solutions of the present invention, and should not be limited to the embodiments described exemplary. Based on one or more 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.

[0024] Reference Figure 1-2The embodiments of the present invention provide a method for simulating the port electrical stress of an electric drive system for a power module under test. The electric drive system includes an inverter with a power module, a DC bus connected to its DC side, and a motor connected to its AC side. Methods for simulating electrical stress at the ports of electric drive systems include: Step S1: Based on the preset motor parameters, inverter parameters, DC bus voltage and task operating condition information of the target electric drive system, construct a benchmark simulation model and output the target port current reference signal, the target port voltage reference signal and the benchmark loss data of the power module under test; Step S2: Configure a common DC bus 100 equivalent to the DC bus voltage, and combine the main converter 200 and slave converter 300 with the DC side connected to the common DC bus 100, and the filter network connected between the AC side of the main converter 200 and slave converter 300 to form a drag test circuit. Step S3: Input the target port current reference signal and the target port voltage reference signal into the host converter 200 and the slave converter 300 respectively, so as to output the actual port current and target port voltage boundary. Combined with the pre-established filter network including the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the host converter 200. Step S4: Set the power module under test in the main power circuit of the host converter, and define the test port as the electrical stress reproduction port. By calling the target port current reference signal and the target port voltage reference signal in sequence on the test circuit, the electrical stress of the port corresponding to the target electric drive system is reproduced on the power module under test and the operating condition simulation test is performed. Step S5: Continuously extract the real-time on / off status of the power module under test, and simultaneously collect the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port. Input the predefined power module loss model, calculate and output the actual loss data of the power module under test corresponding to all on / off cycles, and compare the actual loss data of the power module under test with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

[0025] The proposed method for simulating the electrical stress at the ports of an electric drive system for a power module under test (PDT) constructs a benchmark simulation model by pre-setting the motor parameters, inverter parameters, DC bus voltage, and task operating conditions of the target electric drive system. It outputs a target port current reference signal, a target port voltage reference signal, and benchmark loss data of the PDT power module, thus directly correlating the time-domain variation patterns of the simulated port voltage, simulated port current, and DC bus voltage with the benchmark loss data of the PDT power module. Furthermore, a test circuit is constructed by configuring a common DC bus 100, a master converter 200, a slave converter 300, and a filter network that includes the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and stator resistance. This ensures that the parameters of the filter network correspond to the parameters of the motor stator equivalent inductance and stator resistance, eliminating the deviation between the master converter 200 and the simulated port voltage constraints of the target electric drive system. Finally, the method further utilizes the target port current reference signal and the target port voltage reference signal... Reference signals are input to the host converter 200 and the slave converter 300 respectively to form test ports that are equivalent to the electrical constraints of the reference simulation model port, thereby improving the equivalent accuracy of the electrical boundary of the test port. Furthermore, by setting the power module under test in the power main circuit of the host converter and defining the test port as the electrical stress reproduction port, the operating condition simulation test is carried out by sequentially calling the target port current reference signal and the target port voltage reference signal of the drag test circuit. Simultaneously, the electrical parameters of the electrical stress reproduction port are collected, and the real-time on / off state of the power module under test is extracted and input into the predefined power module loss model to calculate the actual loss data of the power module under test. The loss evaluation result is obtained by comparing it with the reference loss data of the power module under test. This achieves a quantitative assessment of the task operating condition reproduction accuracy of the drag test circuit, and completes a quantitative evaluation closed loop that can be used for reliability testing and thermal design verification. This effectively overcomes the defects of misalignment between simulation and actual measurement reproduction, insufficient port equivalent accuracy, and lack of quantitative evaluation closed loop.

[0026] In one embodiment, in step S1, a benchmark simulation model is constructed and the target port current reference signal, target port voltage reference signal, and reference loss data of the power module under test are output based on the preset target electric drive system's motor parameters, inverter parameters, DC bus voltage, and task operating condition information. Specifically, this includes: Step S11: Based on the inherent hardware parameters of the target electric drive system and the actual vehicle operation conditions, preset the motor parameters, inverter parameters, DC bus voltage, and task condition information of the target electric drive system. The DC bus voltage is represented by the operating voltage of the inverter's DC side. The task condition information includes several task condition stages and the corresponding timing, speed status data, and load torque. Step S12: Call the motor model and inverter model, build a benchmark simulation model on the simulation platform, and input the motor parameters, inverter parameters, DC bus voltage and task operating condition information to perform simulation calculations. Combine the thermoelectric joint loss simulation model and the thermal network model to output the target port current reference signal, the target port voltage reference signal and the benchmark loss data of the power module under test.

[0027] Specifically, motor parameters include, but are not limited to, stator resistance, stator shaft inductance, and stator... Shaft inductance, permanent magnet flux linkage, number of pole pairs, moment of inertia, and damping coefficient; inverter parameters include, but are not limited to, switching frequency, DC bus voltage range, and modulation strategy.

[0028] The task operation phase includes, but is not limited to, at least one of the following: heavy-load start-up phase, constant-speed cruise, deceleration braking, and energy recovery. In the embodiments of the present invention, the preset task operation information of the target electric drive system includes a 0-1.0s heavy-load start-up phase executed sequentially, with corresponding speed data increasing from 0 to 2000 RPM. The load torque is 24 During the 1.0-2.0s constant speed cruising phase, the corresponding engine speed data is maintained at 2000 RPM. Load torque 18 During the deceleration and braking phase of 2.0-2.4 seconds, the corresponding engine speed data is as follows: from 2000... Reduced to 0, load torque 18 .

[0029] In one specific embodiment, in step S12, the motor model and inverter model are invoked to build a benchmark simulation model on the simulation platform. Motor parameters, inverter parameters, DC bus voltage, and task operating condition information are input to perform simulation calculations. This combines the thermoelectric combined loss simulation model and the thermal network model to output the target port current reference signal, the target port voltage reference signal, and the benchmark loss data of the power module under test. Specifically, this includes: Step S121: Based on the motor model, inverter modulation model and DC bus voltage constraint conditions, build a benchmark simulation model on the Simulink or PLECS simulation platform. Step S122: Input the preset motor parameters, inverter parameters, DC bus voltage and task operating condition information into the reference simulation model and perform simulation calculations to output the stator three-phase current waveform and back EMF waveform based on the motor model side, and output the inverter switching state, simulation port voltage and simulation port current based on the inverter modulation model side. Step S123: Extract the stator three-phase current waveform as the target port current reference signal, and extract the back electromotive force waveform as the target port voltage reference signal; Step S124: Input the simulation port voltage, simulation port current and inverter switching state into the thermoelectric joint loss simulation model, so as to calculate the conduction loss and switching loss of several power devices in the power module under test based on the pre-acquired conduction characteristic parameters and switching characteristic parameters of the power devices. Step S125: Input the conduction loss and switching loss into the thermal network model to perform feedback correction, so as to output the reference loss data of the power module under test.

[0030] Specifically, the motor model in the embodiments of the present invention may be a permanent magnet synchronous motor model, an induction motor model, or a surface-mounted permanent magnet synchronous motor. It consists of a shaft mathematical model combined with rotor motion equations.

[0031] The specific working principles of the above-mentioned motor model, inverter modulation model, thermoelectric combined loss simulation model, and thermal network model are all existing technologies, and will not be elaborated further in this invention.

[0032] The conduction and switching characteristics of the power devices are pre-obtained from the device datasheets. In this embodiment, the power devices are IGBTs and anti-parallel diodes (FWDs), which together undertake power conversion and generate corresponding conduction and switching losses. A thermal network model can be used to introduce junction temperature for feedback correction, eliminating the deviation caused by temperature in loss calculations, thereby obtaining reference loss data for the power module under test.

[0033] It is worth noting that the conduction loss of IGBTs for: In the formula: Represented as the temperature-related characteristic parameters recorded in the device datasheet; This represents the collector current of the IGBT; Indicated as junction temperature; Expressed as duty cycle; IGBT switching losses for: In the formula: This is expressed as the switching frequency of the power device; and These are represented as the IGBT turn-on energy and turn-off energy given in the device datasheet. It is expressed as DC bus voltage.

[0034] FWD conduction loss for: In the formula: Represented as the temperature-related characteristic parameters recorded in the device datasheet; This indicates the current flowing from the anode to the cathode when the FWD is forward-biased; It should be understood that the present invention is not limited thereto, and the specific calculation of conduction loss and / or switching loss should be based on the specific structure of the power module under test in the actual electric drive system.

[0035] Figure 2 This is a schematic diagram of the topology of the drag test circuit according to an embodiment of the present invention.

[0036] like Figure 2 As shown, in one embodiment, in step S2, a common DC bus 100 equivalent to the DC bus voltage is configured. A main converter 200 and a slave converter 300, both with their DC sides connected to the common DC bus 100, and a filter network connected between the AC sides of the main converter 200 and the slave converter 300, are combined to form a reverse-drive test circuit. Specifically, this includes: Step S21: Configure the common DC bus 100 and set the voltage of the common DC bus 100 to be equal to the DC bus voltage of the target electric drive system; Step S22: Configure the master converter 200 and the slave converter 300, and connect the DC side of both the master converter 200 and the slave converter 300 to the common DC bus 100. Step S23: Connect an LCL (inductor-capacitor-inductor) filter 400 between the AC side of the master converter 200 and the slave converter 300 to form a reverse test circuit.

[0037] Specifically, the common DC bus 100, which is equivalent to the DC bus voltage, can ensure that the DC side electrical conditions of the test circuit are consistent with the target electric drive system, thus eliminating test errors caused by DC bus voltage differences.

[0038] By connecting the DC sides of both the master converter 200 and the slave converter 300 to the common DC bus 100, a dual-converter common DC bus 100 test circuit architecture can be realized, enabling internal energy circulation between the master converter 200 and the slave converter 300 without the need for an external real motor.

[0039] Furthermore, the use of a symmetrical structure between the master converter 200 and the slave converter 300 can reduce differences in hardware selection, reduce asymmetric compensation logic in the control algorithm, simplify the hardware setup of the test circuit and the difficulty of debugging control parameters, and improve the consistency of test results.

[0040] In the embodiments of the present invention, the common DC bus 100 is constructed using a DC power supply and a DC bus capacitor; the master converter 200 and the slave converter 300 are both three-phase voltage source inverters.

[0041] In one embodiment, after connecting an LCL filter 400 between the AC sides of the master converter 200 and the slave converter 300 in step S23 to form a reverse-drive test circuit, the method further includes: Extract the stator equivalent phase inductance and stator resistance of the motor in the target electric drive system, establish the correspondence between the filter inductance and the stator equivalent phase inductance of the LCL filter 400, as well as the correspondence between its equivalent resistance and the stator resistance, to obtain an LCL filter including the correspondence between the filter inductance and the motor stator equivalent phase inductance, and the equivalent resistance and the stator resistance.

[0042] Specifically, by establishing a matching relationship between the filter inductance and equivalent resistance of the LCL filter 400 and the equivalent phase inductance and stator resistance of the motor stator, the hardware impedance value of the LCL filter 400 itself is made close to the stator impedance of the motor. This provides the necessary hardware foundation for the subsequent formation of a test port on the main converter 200 that is equivalent to the port electrical constraints of the reference simulation model, thus eliminating the inherent test deviation caused by hardware parameter mismatch.

[0043] In one embodiment, in step S3, the target port current reference signal and the target port voltage reference signal are input to the master converter 200 and the slave converter 300, respectively, to output the actual port current and target port voltage boundaries. Combined with a pre-established filter network including the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the master converter 200. Specifically, this includes: Step S31: Input the target port current reference signal into the host converter 200 to output the actual port current; Step S32: Input the target port voltage reference signal into the slave converter 300 to output the target port voltage boundary; Step S33: Invoke the LCL filter 400, which includes the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance. Apply the actual port current and the target port voltage boundary to both ends of the LCL filter 400 to form a test port on the AC side of the main converter 200 that is equivalent to the port electrical constraints of the reference simulation model.

[0044] Specifically, when the actual port current and the target port voltage boundary are simultaneously applied to both ends of the LCL filter 400, the interaction between voltage and current in the hardware circuit is established, so that the actual electrical constraint relationship on the AC side of the main converter 200 approximates the port electrical constraint obtained by the benchmark simulation model, thereby constructing a test port on the AC side of the main converter 200.

[0045] Since the port voltage of the master converter 200 is jointly determined by the voltage drop of the LCL filter 400 and the target port voltage boundary established by the slave converter 300, after the LCL filter 400 is matched with the stator impedance of the motor, the impedance and dynamic terms of the port electrical constraints of the AC side of the master converter 200 correspond to the port electrical constraints of the target electric drive system. This replicates the real electrical relationship of the target electric drive system from a mechanistic perspective, ensuring that the voltage and current dynamic electrical stress applied to the power module under test by the test port of the master converter 200 are accurately reproduced. This provides a reliable hardware foundation for improving the credibility of the test results of the power module under test loss.

[0046] In one embodiment, in step S4, the power module under test is placed in the main power circuit of the host converter, and the test port is defined as the electrical stress reproduction port. By sequentially calling the target port current reference signal and the target port voltage reference signal on the test circuit, the port electrical stress corresponding to the target electric drive system is reproduced on the power module under test, and the operating condition simulation test is performed. Specifically, this includes: Step S41: Set the power module under test in the main power circuit of the main converter and define the test port as the electrical stress reproduction port; Step S42: The test circuit is called sequentially according to the simulation time axis of the target port current reference signal, and the actual output current of the AC side of the main converter 200 is collected. Closed-loop regulation is performed based on the difference between the target port current reference signal and the actual output current to output the actual port current in real time. Step S43: The test circuit is called sequentially according to the simulation time axis of the target port voltage reference signal, and the three-phase actual voltage of the filter capacitor port of LCL filter 400 and the three-phase current of the AC side of slave converter 300 are collected. Closed-loop regulation is performed on the three-phase actual voltage and three-phase current based on the target port voltage reference signal to output the target port voltage boundary in real time. Step S44: Apply the real-time output of the actual port current and the target port voltage boundary to both ends of the LCL filter 400 to reproduce the port electrical stress corresponding to the target electric drive system on the power module under test and perform operating condition simulation test.

[0047] In one specific embodiment, in step S42, the test circuit is called sequentially according to the simulation time axis of the target port current reference signal, and the actual output current of the AC side of the host converter 200 is collected. Closed-loop regulation is performed based on the difference between the target port current reference signal and the actual output current to output the actual port current in real time. Specifically, this includes: Step S421: Perform a time-by-time call on the test circuit based on the simulation time axis of the target port current reference signal; Step S422: Collect the actual output current on the AC side of the main inverter 200; Step S423: Utilize a phase-locked loop (PLL) A Locked Loop (PLL) is used to obtain the phase angle of the target electric drive system, and then the Clarke and Park transformations are performed sequentially on the actual output current to convert it into... Rotating coordinate system The actual current components of the shaft and Actual current component of the shaft; Step S424: Convert the target port current reference signal called sequentially to... To obtain in a rotated coordinate system Shaft current reference components and Shaft current reference component; Step S425: Calculation The actual current component of the shaft and Axis current reference component, and The actual current component of the shaft and The difference between the shaft current reference components is obtained. Shaft current error and Shaft current error; Step S426: ... Shaft current error and The ratio corresponding to the shaft current error input Integral controller (Proportional) Integral Controller (PI) to obtain The main converter 200 in the rotating coordinate system Shaft reference voltage signal and Shaft reference voltage signal; Step S427: For Shaft reference voltage signal and The shaft reference voltage signal is sequentially subjected to inverse Park transformation and inverse Clarke transformation, and then input into the pulse-width modulation (PWM) module to generate a drive signal, which controls the on / off switching of the power module under test in the power main circuit of the host converter 200 to output the actual port current.

[0048] Specifically, this embodiment can realize the mapping of the simulation operating condition timing to the hardware control by calling the target port current reference signal in a time sequence, ensuring that the control timing of the AC side of the host converter 200 is synchronized with the simulation operating condition timing, and reproducing the dynamic change characteristics of the operating condition over time.

[0049] The actual output current on the AC side of the main converter 200 can be acquired through a Hall current sensor or a coaxial shunt, thus providing feedback for closed-loop regulation. By combining the phase angle obtained from the PLL with sequential Clarke and Park transformations of the actual output current, the actual output current can be transformed from its three-phase stationary coordinate system to a two-phase stationary coordinate system. The coordinate system current, then transformed using the phase angle as a reference, is converted to... In a rotated coordinate system, to obtain The actual current components of the shaft and The actual current component of the shaft is obtained, which facilitates the subsequent PI controller to achieve zero steady-state error closed-loop regulation.

[0050] Shaft current error and Obtaining the shaft current error quantifies the deviation of the actual output current from the target reference current corresponding to the target port current reference signal at the current moment. After being input to the PI controller, the PI controller is used to eliminate the steady-state current error and output the correct current. Shaft reference voltage signal and The shaft reference voltage signal enables closed-loop correction of the actual output current.

[0051] Furthermore, through the analysis of Shaft reference voltage signal and The shaft reference voltage signal is restored, and the on / off control of the power module under test is performed so that the actual port current of the main converter 200 tracks the target port current reference signal, and the current stress of the stator phase current amplitude, frequency and timing changes of the target electric drive system is reproduced, thereby significantly improving the accuracy of port electrical stress simulation.

[0052] The specific principles of PLL, Clarke transform, Park transform, PI controller and PWM modulation module are all existing technologies, and will not be elaborated further in this invention.

[0053] In one specific embodiment, in step S43, the test circuit is called sequentially according to the simulation time axis of the target port voltage reference signal, and the three-phase actual voltage of the filter capacitor port of the LCL filter 400 and the three-phase current on the AC side of the slave converter 300 are collected. Closed-loop regulation is performed on the three-phase actual voltage and three-phase current based on the target port voltage reference signal to output the target port voltage boundary in real time. Specifically, this includes: Step S431: Perform a time-by-time call on the test circuit based on the simulation time axis of the target port voltage reference signal; Step S432: Collect the actual three-phase voltage at the filter capacitor port of the LCL filter 400 and the three-phase current on the AC side of the slave converter 300. Step S433: Based on the phase angle, perform Clarke transform and Park transform on both the actual three-phase voltage and the three-phase current sequentially, and convert them into... Rotating coordinate system Actual voltage components of the shaft and The actual voltage component of the shaft, and Axis current components and Axis current components; Step S434: Convert the target port voltage reference signal called sequentially to... To obtain in a rotated coordinate system Shaft voltage reference components and Shaft voltage reference component, and corresponding calculation. Actual voltage components of the shaft and The difference between the actual voltage components of the shaft is obtained. Shaft voltage error and Shaft voltage error; Step S435: ... Shaft voltage error and The PI controller corresponding to the shaft voltage error input outputs... Shaft current reference components and The shaft current reference component is calculated accordingly. Axis current components and The difference between the shaft current components is obtained. Shaft current error and Shaft current error; Step S436: ... Shaft current error and The shaft current error is input to the corresponding PI controller to obtain... Slave converter 300 in rotating coordinate system Shaft reference voltage signal and Shaft reference voltage signal; Step S437: For Shaft reference voltage signal and The shaft reference voltage signal undergoes inverse Park transformation and inverse Clarke transformation in sequence, and is input into the PWM modulation module to generate a drive signal, which controls the on / off switching of the power module in the slave converter 300 to output the target port voltage boundary.

[0054] Specifically, this embodiment can realize the mapping of the simulation operating condition timing to hardware control by calling the target port voltage reference signal in a time sequence, ensuring that the control timing of the slave converter 300 is synchronized with the master converter 200, and reproducing the dynamic timing changes of the back electromotive force of the target electric drive system.

[0055] The actual three-phase voltage is acquired through a high-voltage differential probe or a resistor divider network, while the actual three-phase current is acquired through a Hall current sensor or a coaxial shunt to obtain the true feedback from the hardware loop. The actual three-phase voltage is acquired from the filter capacitor port to directly locate the target voltage point to be controlled. The true feedback value of the target voltage point can be obtained directly without additional conversion. The three-phase current is used for inner loop current limiting and rapid correction, providing feedback basis for closed-loop regulation.

[0056] Convert the actual three-phase voltage and three-phase current to In a rotating coordinate system, the PI controller can easily achieve zero steady-state error closed-loop regulation, ensuring the regulation accuracy of the voltage outer loop and the current inner loop.

[0057] Shaft voltage error and Obtaining the shaft voltage error enables steady-state tracking of the port voltage at the target voltage point and provides a rapid correction basis for the inner current loop regulation. Shaft current error and By acquiring the shaft current error, a dual closed-loop control architecture for voltage and current is realized, which can effectively balance voltage steady-state accuracy and current dynamic protection response.

[0058] Furthermore, through Shaft reference voltage signal and The output and restoration of the shaft reference voltage signal enable the on / off control of the power module configured in the slave converter 300. In conjunction with the LCL filter 400, the voltage boundary corresponding to the simulation is established. Together with the output current of the master converter 200, the target port voltage boundary of the target electric drive system port is reproduced, effectively improving the dynamic response speed and anti-disturbance capability of the target port voltage boundary.

[0059] Therefore, it can be seen that by cooperating with the current closed-loop control of the master converter 200 and the voltage-current dual closed-loop control of the slave converter 300, the master converter 200 accurately tracks the target port current, and the slave converter 300 establishes the target port voltage boundary that matches the simulation timing. This voltage boundary is then transmitted to the test port of the master converter 200 via the LCL filter 400, so that the test port is simultaneously subject to both current and voltage constraints. This allows the electrical stress corresponding to the target electric drive system to be reproduced at the test port, achieving synchronous simulation of port voltage and port current. Therefore, defining the test port as the electrical stress reproduction port can ensure the accuracy of the operating condition simulation test of the power module under test.

[0060] In one embodiment, in step S5, the real-time on / off state of the power module under test is continuously extracted, and the current port voltage, current port current, and current DC bus voltage of the electrical stress reproduction port are simultaneously collected. A predefined power module loss model is input, and the actual loss data of the power module under test corresponding to all on / off cycles is calculated and output. The actual loss data of the power module under test is compared with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test, specifically including: Step S51: Based on the preset sampling frequency, continuously extract the real-time on / off state of the power module under test, and simultaneously collect the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port; Step S52: Perform low-pass filtering on the current port voltage, current port current and current DC bus voltage, and input them into the power module loss model in combination with the real-time on / off state of the power module under test; Step S53: Based on the sampling timing of each on / off cycle, calculate and accumulate the conduction loss and switching loss of each power device in the power module under test cycle to obtain the total device loss corresponding to each on / off cycle. The on / off cycle represents the time period for each power device to perform one on / off switching. Step S54: Match the total device loss corresponding to each on / off cycle with each task condition stage in the task condition information to obtain the actual loss data of the power module under test. Step S55: Compare the actual loss data of the power module under test with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

[0061] Specifically, the acquisition of the current port voltage, current port current, and current DC bus voltage is based on the same principle as the voltage and current acquisition in the above embodiment. The calculation of the conduction loss and switching loss of each power device is also based on the same principle as the loss calculation of IGBT and FWD. This embodiment will not elaborate further here.

[0062] In addition, the preset sampling frequency is no less than 5 times the switching frequency, which can ensure that there are enough sampling points in a complete switching cycle, fully capture the switching ripple caused by the operation of power devices, avoid the loss of transient electrical information due to insufficient sampling frequency, and provide reliable raw sampling data for accurate calculation of total device losses.

[0063] The real-time on / off state of each power device can be extracted by directly reading the drive signal output by the PWM modulation module to obtain the theoretical switching timing, or by comparing the voltage across the power device to detect the actual on / off time of the power device.

[0064] Therefore, by synchronously acquiring the electrical signals of the electrical stress reproduction port and the real-time on / off status of the power devices, loss calculation is carried out in units of on / off cycles. Combined with the task operating condition information, loss segmentation statistics are completed, and then compared with the reference loss data of the power module under test for evaluation. This can fully capture the on / off ripple of the power devices, ensure that the loss calculation is aligned with the actual working process of the power devices, achieve high-precision quantification of the actual loss of the power module under test, objectively evaluate the reproduction accuracy of the port electrical stress and loss characteristics of the target electric drive system under task operating conditions of the test circuit, and thus ensure the reliability of the loss evaluation results of the power module under test.

[0065] It is worth noting that the evaluation results of the power module under test may include the relative error of the average loss in each task operation phase, the root mean square error of the loss waveform, and the peak loss error. This invention is not limited to these, and the specific evaluation results are determined by the user's implementation requirements.

[0066] In an embodiment of the present invention, the power module under test is a single-phase bridge arm power module, and the obtained reference loss data of the power module under test includes: the average loss of the upper IGBT is 47.75W; the average loss of the upper FWD is 26.28W; the average loss of the lower IGBT is 49.66W; the average loss of the lower FWD is 20.54W; the total average loss during the heavy load start-up phase is 144.23W; the total average loss during the constant speed cruise phase is 66.02W; and the total average loss during the deceleration and braking phase is 40.22W.

[0067] The actual loss data of the power module under test include: the total average loss during the heavy load start-up phase is 142.76W, with a relative error of 1.02%; the total average loss during the constant speed cruise phase is 64.49W, with a relative error of 2.32%; and the total average loss during the deceleration and braking phase is 40.30W, with a relative error of 0.20%.

[0068] Therefore, it can be seen that the relative error of the total average loss of the power module under test reproduced by the electric drive system port electrical stress simulation method of the present invention is controlled within 3%, indicating that the present invention can reproduce the loss characteristics of the power module of the electric drive system under the task conditions with high precision, and has good port electrical stress reproduction capability and loss consistency.

[0069] Accordingly, refer to Figure 3 Embodiments of the present invention also provide an electric drive system port electrical stress simulation system for a power under test module, used to implement the electric drive system port electrical stress simulation method for a power under test module as described in any of the above embodiments. The electric drive system port electrical stress simulation system includes: The benchmark data acquisition module is used to construct a benchmark simulation model and output the target port current reference signal, the target port voltage reference signal and the benchmark loss data of the power module under test based on the preset target electric drive system's motor parameters, inverter parameters, DC bus voltage and task operating condition information. A test circuit forming module is used to configure a common DC bus 100 equivalent to the DC bus voltage, and to combine a master converter 200 and a slave converter 300 whose DC sides are both connected to the common DC bus 100, and a filter network connected between the AC sides of the master converter 200 and the slave converter 300 to form a test circuit. The test port forming module can input the target port current reference signal and the target port voltage reference signal into the host converter 200 and the slave converter 300 respectively, so as to output the actual port current and the target port voltage boundary. Combined with the pre-established filter network including the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the host converter 200. The simulation execution module can set the power module under test in the power main circuit of the host converter and define the test port as the electrical stress reproduction port. By calling the target port current reference signal and the target port voltage reference signal in sequence on the drag test circuit, the electrical stress of the port corresponding to the target electric drive system can be reproduced on the power module under test and the operating condition simulation test can be performed. The evaluation result acquisition module is used to continuously extract the real-time on / off status of the power module under test, and simultaneously collect the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port. It inputs a predefined power module loss model, calculates and outputs the actual loss data of the power module under test for each on / off cycle, and compares the actual loss data of the power module under test with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

[0070] Specifically, the predefined power module loss model is based on the above formulas for conduction loss and / or switching loss.

[0071] The electrical stress simulation system for the electric drive system port of the power under test module proposed in this invention belongs to the same general inventive concept as the electrical stress simulation method for the electric drive system port of the power under test module of this invention. It should at least have the same technical effect as the electrical stress simulation method for the electric drive system port of the power under test module of this invention. Therefore, this invention will not elaborate further here.

[0072] While one or more embodiments of the present invention have been described above, those skilled in the art will recognize that the present invention can be implemented in any other form without departing from its spirit and scope. Therefore, the embodiments described above are illustrative and not restrictive, and many modifications and substitutions will be apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for simulating port electrical stress of an electric drive system for a power module under test, characterized in that, The electric drive system includes an inverter with power modules, a DC bus connected to its DC side, and a motor connected to its AC side. Methods for simulating electrical stress at the ports of electric drive systems include: Based on the preset target electric drive system's motor parameters, inverter parameters, DC bus voltage, and task operating condition information, a benchmark simulation model is constructed and the target port current reference signal, target port voltage reference signal, and the benchmark loss data of the power module under test are output. A common DC bus with voltage equivalent to the DC bus voltage is configured, and a main converter and a slave converter with DC sides connected to the common DC bus, and a filter network connected between the AC sides of the main converter and the slave converter are combined to form a drag test circuit. The target port current reference signal and the target port voltage reference signal are input to the master converter and the slave converter respectively, so as to output the actual port current and the target port voltage boundary. Combined with the pre-established filter network including the correspondence between the filter inductor and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the master converter. The power module under test is set in the main power circuit of the host converter, and the test port is defined as the electrical stress reproduction port. By calling the target port current reference signal and the target port voltage reference signal in sequence on the drag test circuit, the port electrical stress corresponding to the target electric drive system is reproduced on the power module under test and the operating condition simulation test is performed. The real-time on / off status of the power module under test is continuously extracted, and the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port are collected simultaneously. A predefined power module loss model is input, and the actual loss data of the power module under test corresponding to all on / off cycles is calculated and output for each on / off cycle. The actual loss data of the power module under test is compared with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

2. The method for simulating port electrical stress of an electric drive system for a power module under test according to claim 1, characterized in that, The process involves constructing a benchmark simulation model based on preset target electric drive system motor parameters, inverter parameters, DC bus voltage, and task operating condition information, and outputting target port current reference signal, target port voltage reference signal, and benchmark loss data of the power module under test. Specifically, this includes: Based on the inherent hardware parameters of the target electric drive system and the actual vehicle operation conditions, the motor parameters, inverter parameters, DC bus voltage, and task condition information of the target electric drive system are preset. Among them, the DC bus voltage represents the operating voltage of the inverter on the DC side; the task condition information includes several task condition stages and corresponding timing, speed status data, and load torque. The motor model and inverter model are called to build a benchmark simulation model on the simulation platform. The motor parameters, inverter parameters, DC bus voltage and task operating condition information are input to perform simulation calculations. Combined with the thermoelectric joint loss simulation model and the thermal network model, the target port current reference signal, the target port voltage reference signal and the benchmark loss data of the power module under test are output.

3. The method for simulating port electrical stress of an electric drive system for a power module under test according to claim 2, characterized in that, The process involves calling the motor model and inverter model, building a benchmark simulation model on the simulation platform, and inputting motor parameters, inverter parameters, DC bus voltage, and task operating condition information to perform simulation calculations. This is combined with the thermoelectric combined loss simulation model and the thermal network model to output the target port current reference signal, the target port voltage reference signal, and the benchmark loss data of the power module under test. Specifically, this includes: A benchmark simulation model is built on the Simulink or PLECS simulation platform based on the motor model, the inverter modulation model and the DC bus voltage constraint. Input preset motor parameters, inverter parameters, DC bus voltage and task operating condition information into the reference simulation model and perform simulation calculations to output stator three-phase current waveform and back EMF waveform based on the motor model side, and output inverter switching state, simulation port voltage and simulation port current based on the inverter modulation model side. The stator three-phase current waveform is extracted and defined as the target port current reference signal, and the back electromotive force waveform is extracted and defined as the target port voltage reference signal; The simulated port voltage, simulated port current, and inverter switching state are input into the thermoelectric joint loss simulation model to calculate the conduction loss and switching loss of several power devices in the power module under test based on the pre-acquired conduction characteristic parameters and switching characteristic parameters of the power devices. The conduction loss and switching loss are input into the thermal network model to perform feedback correction, so as to output the reference loss data of the power module under test.

4. The method for simulating port electrical stress of an electric drive system for a power module under test according to claim 3, characterized in that, The configuration includes a common DC bus equivalent to the DC bus voltage. This, combined with a master converter and a slave converter whose DC sides are both connected to the common DC bus, and a filter network connecting the AC sides of the master converter and the slave converter, forms a reverse-drive test circuit. Specifically, it includes: Configure a common DC bus and set the voltage of the common DC bus to be equal to the DC bus voltage of the target electric drive system; Configure a master converter and a slave converter, and connect the DC side of both the master converter and the slave converter to a common DC bus; An LCL filter is connected between the AC sides of the master converter and the slave converter to form a reverse-drive test circuit.

5. The method for simulating port electrical stress of an electric drive system for a power module under test according to claim 4, characterized in that, The target port current reference signal and target port voltage reference signal are respectively input to the master converter and slave converter to output the actual port current and target port voltage boundaries. Combined with a pre-established filter network including the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the master converter. Specifically, this includes: Input the target port current reference signal into the main converter to output the actual port current; Input the target port voltage reference signal into the slave converter to output the target port voltage boundary; An LCL filter, which includes the correspondence between the filter inductance and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, is invoked. The actual port current and the target port voltage boundary are applied to both ends of the LCL filter to form a test port on the AC side of the main converter that is equivalent to the port electrical constraints of the reference simulation model.

6. The method for simulating port electrical stress of an electric drive system for a power module under test according to claim 5, characterized in that, The process involves placing the power module under test in the main power circuit of the main inverter and defining the test port as an electrical stress reproduction port. By sequentially calling the target port current reference signal and the target port voltage reference signal through the drag test circuit, the electrical stress corresponding to the target electric drive system at the port of the power module under test is reproduced, and a working condition simulation test is performed. Specifically, this includes: The power module under test is set in the main power circuit of the main converter, and the test port is defined as the electrical stress reproduction port. The test circuit is called sequentially according to the simulation time axis of the target port current reference signal, and the actual output current of the AC side of the main converter is collected. Closed-loop regulation is performed based on the difference between the target port current reference signal and the actual output current to output the actual port current in real time. The test circuit is called sequentially according to the simulation time axis of the target port voltage reference signal, and the three-phase actual voltage of the filter capacitor port of the LCL filter and the three-phase current of the AC side of the slave converter are collected. Based on the target port voltage reference signal, the three-phase actual voltage and three-phase current are adjusted in a closed loop to output the target port voltage boundary in real time. The actual port current and target port voltage boundary are applied to both ends of the LCL filter in real time to reproduce the port electrical stress corresponding to the target electric drive system on the power module under test and perform operating condition simulation test.

7. The method for simulating port electrical stress of an electric drive system for a power module under test according to claim 6, characterized in that, The test circuit performs a time-sequential call to the target port current reference signal based on the simulation time axis, and collects the actual output current on the AC side of the main converter. It then performs closed-loop regulation based on the difference between the target port current reference signal and the actual output current to output the actual port current in real time. Specifically, this includes: The test circuit is called sequentially according to the simulation time axis of the target port current reference signal; Collect the actual output current on the AC side of the main converter; The phase angle of the target electric drive system is obtained using a PLL, and Clarke and Park transformations are sequentially performed on the actual output current to convert it into... Rotating coordinate system The actual current components of the shaft and Actual current component of the shaft; The target port current reference signal of the time-sequential call is converted to To obtain in a rotated coordinate system Shaft current reference components and Shaft current reference component; calculate The actual current component of the shaft and Axis current reference component, and The actual current component of the shaft and The difference between the shaft current reference components is obtained. Shaft current error and Shaft current error; Will Shaft current error and The shaft current error is input to the corresponding PI controller to obtain... The main converter in the rotating coordinate system Shaft reference voltage signal and Shaft reference voltage signal; right Shaft reference voltage signal and The shaft reference voltage signal is sequentially subjected to inverse Park transform and inverse Clarke transform, and then input into the PWM modulation module to generate a drive signal, which controls the on / off state of the power module under test in the main power circuit of the host converter to output the actual port current.

8. The method for simulating port electrical stress of an electric drive system for a power module under test according to claim 7, characterized in that, The test circuit performs time-sequential calls based on the simulation time axis of the target port voltage reference signal, and acquires the three-phase actual voltage at the filter capacitor port of the LCL filter and the three-phase current on the AC side of the slave converter. Based on the target port voltage reference signal, it performs closed-loop regulation on the three-phase actual voltage and three-phase current to output the target port voltage boundary in real time, specifically including: The test circuit is called sequentially according to the simulation time axis of the target port voltage reference signal; The actual three-phase voltage at the filter capacitor port of the LCL filter and the three-phase current on the AC side of the slave converter are collected. Based on the phase angle, Clarke and Park transformations are sequentially performed on the actual three-phase voltages and currents, and then converted to... Rotating coordinate system Actual voltage components of the shaft and The actual voltage component of the shaft, and Axis current components and Axis current components; The target port voltage reference signal called sequentially is converted to To obtain in a rotated coordinate system Shaft voltage reference components and Shaft voltage reference component, and corresponding calculation. Actual voltage components of the shaft and The difference between the actual voltage components of the shaft is obtained. Shaft voltage error and Shaft voltage error; Will Shaft voltage error and The PI controller corresponding to the shaft voltage error input outputs... Shaft current reference components and The shaft current reference component is calculated accordingly. Axis current components and The difference between the shaft current components is obtained. Shaft current error and Shaft current error; Will Shaft current error and The shaft current error is input to the corresponding PI controller to obtain... Slave converter in rotating coordinate system Shaft reference voltage signal and Shaft reference voltage signal; right Shaft reference voltage signal and The shaft reference voltage signal undergoes inverse Park transform and inverse Clarke transform sequentially, and is input into the PWM modulation module to generate drive signals, controlling the on / off switching of the power module in the slave converter to output the target port voltage boundary.

9. The method for simulating port electrical stress of an electric drive system for a power module under test according to claim 8, characterized in that, The system continuously extracts the real-time on / off state of the power module under test and simultaneously collects the current port voltage, current port current, and current DC bus voltage of the electrical stress reproduction port. A predefined power module loss model is input, and the actual loss data of the power module under test for each on / off cycle is calculated and output. The actual loss data of the power module under test is compared with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test, specifically including: Based on the preset sampling frequency, the real-time on / off status of the power module under test is continuously extracted, and the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port are collected simultaneously. The current port voltage, current port current and current DC bus voltage are low-pass filtered, and the predefined power module loss model is input in combination with the real-time on / off state of the power module under test. Based on the sampling timing of each on / off cycle, the conduction loss and switching loss of each power device in the power module under test are calculated and accumulated for each on / off cycle to obtain the total device loss corresponding to each on / off cycle. The on / off cycle is the time period for each power device to perform one on / off switching. Match the total device loss corresponding to each on / off cycle with each task condition stage in the task condition information to obtain the actual loss data of the power module under test. The actual loss data of the power module under test is compared with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

10. A simulation system for port electrical stress of an electric drive system for a power module under test, characterized in that, For implementing the electric drive system port electrical stress simulation method for a power module under test as described in any one of claims 1-9, the electric drive system port electrical stress simulation system comprises: The benchmark data acquisition module is used to construct a benchmark simulation model and output the target port current reference signal, the target port voltage reference signal and the benchmark loss data of the power module under test based on the preset target electric drive system's motor parameters, inverter parameters, DC bus voltage and task operating condition information. A test circuit module is formed by configuring a common DC bus equivalent to the DC bus voltage, and combining a master converter and a slave converter whose DC sides are both connected to the common DC bus, and a filter network connected between the AC sides of the master converter and the slave converter to form a test circuit. The test port forming module can input the target port current reference signal and the target port voltage reference signal into the master converter and the slave converter respectively, so as to output the actual port current and target port voltage boundary. Combined with the pre-established filter network including the correspondence between the filter inductor and the equivalent phase inductance of the motor stator, and the equivalent resistance and the stator resistance, a test port equivalent to the port electrical constraints of the reference simulation model is formed on the master converter. The simulation execution module can set the power module under test in the power main circuit of the host converter and define the test port as the electrical stress reproduction port. By calling the target port current reference signal and the target port voltage reference signal in sequence on the drag test circuit, the electrical stress of the port corresponding to the target electric drive system can be reproduced on the power module under test and the operating condition simulation test can be performed. The evaluation result acquisition module is used to continuously extract the real-time on / off status of the power module under test, and simultaneously collect the current port voltage, current port current and current DC bus voltage of the electrical stress reproduction port. It inputs a predefined power module loss model, calculates and outputs the actual loss data of the power module under test for each on / off cycle, and compares the actual loss data of the power module under test with the reference loss data of the power module under test to obtain the loss evaluation result of the power module under test.

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