Method and device for determining loss of power module and vehicle

Abstract

The invention provides a power module loss determination method and device and a vehicle, and the method is applied to the technical field of power module loss evaluation, and the method comprises the steps: obtaining a preset conduction loss model and a preset switching loss model corresponding to a power module, and determining a target parameter type and at least one switching frequency group; on-off control is carried out on a power module in the inverter circuit based on the switching frequency in the switching frequency group, and a test data set corresponding to the switching frequency is acquired in the on-off control process; and constructing a target power loss model according to the test data set corresponding to the switching frequency group, a preset conduction loss model and a preset switching loss model, so as to determine the actual power loss of the power module based on the target power loss model in the operation process of the inverter circuit. According to the method, after the IGBT is applied to the inverter circuit, the construction of the target power loss model can be completed based on an actual application scene, so that the power loss calculation accuracy in the application process is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power module loss evaluation, and more particularly, to a power module loss determination method, a determination device and a vehicle in the field of power module loss evaluation. BACKGROUND

[0002] As the core component of the power electronic converter power assembly, the reliability of the IGBT (Insulated Gate Bipolar Transistor) is crucial to the reliability of the power electronic converter.

[0003] In the related art, the measurement of power loss is completed before the IGBT is applied to the target circuit, and then after being applied to the target circuit, the circuit control and optimization are performed according to the power loss measured in advance. However, the loss test precision of this method is low, which reduces the circuit control precision. SUMMARY

[0004] The present application provides a power module loss determination method, a determination device and a vehicle, which can complete the construction of a target power loss model based on the actual application scenario after the IGBT is applied to the inverter circuit, thereby improving the power loss calculation precision in the application process and guaranteeing the operation effect of the actual circuit.

[0005] In a first aspect, a power module loss determination method is provided, applied to an inverter circuit, which includes: obtaining a preset conduction loss model and a preset switching loss model corresponding to a power module, and determining a target parameter type and at least one switching frequency group according to the preset conduction loss model and the preset switching loss model; controlling the on-off of the power module in the inverter circuit based on the switching frequency in the switching frequency group, and obtaining a test data set corresponding to the switching frequency in the on-off control process, wherein the test data set includes at least one test data group, and the data type in the test data group corresponds to the target parameter type; constructing a target power loss model according to the test data set corresponding to the switching frequency group, the preset conduction loss model and the preset switching loss model, so as to determine the actual power loss of the power module based on the target power loss model in the operation process of the inverter circuit.

[0006] The loss determination method of the power module in the embodiment of the application comprises the following steps: after an inverter circuit is constructed by using a power module, a preset conduction loss model and a preset switching loss model corresponding to the power module are obtained; a target parameter type and at least one switching frequency group are determined according to the preset conduction loss model and the preset switching loss model; then, the power module in the inverter circuit is controlled to turn on and turn off based on the switching frequency in the switching frequency group; and during the on-off control process, a test data set corresponding to the switching frequency is obtained, wherein the test data set comprises at least one test data group, the data type in the test data group corresponds to the target parameter type, and a target power loss model is constructed according to the test data set corresponding to the switching frequency group, the preset conduction loss model and the preset switching loss model, so that the actual power loss of the power module is determined based on the target power loss model during the operation of the inverter circuit. Therefore, the method can construct a target power loss model based on an actual application scenario after the inverter circuit is constructed, thereby improving the calculation accuracy of the power loss in the application process and ensuring the operation effect of the actual circuit.

[0007] In combination with the first aspect, in some possible implementation manners, the power module comprises an IGBT and a diode connected in anti-parallel, the preset conduction loss model and the preset switching loss model corresponding to the power module are obtained by determining a first conduction loss model and a first switching loss model corresponding to the IGBT; determining a second conduction loss model and a second switching loss model corresponding to the diode; and determining the preset conduction loss model according to the first conduction loss model and the second conduction loss model; and determining the preset switching loss model according to the first switching loss model and the second switching loss model.

[0008] In combination with the first aspect and the above implementation manner, in some possible implementation manners, the switching frequency group comprises a first switching frequency and a second switching frequency, and in the same current and voltage test working condition, a first switching loss corresponding to the first switching frequency is greater than a second switching loss corresponding to the second switching frequency, and the first switching loss and the second switching loss are in a multiple relationship, and a first conduction loss corresponding to the first switching frequency is equal to a second conduction loss corresponding to the second switching frequency.

[0009] Based on the above embodiment, the IGBT power loss collected respectively by the first switching frequency and the second switching frequency in the same switching frequency group can be used to calculate the corresponding switching loss and conduction loss, which can meet the data fitting calculation requirement and ensure the model construction accuracy.

[0010] In a possible implementation manner of the first aspect, the target parameter type comprises a power loss of the power module, the test data set corresponding to the switch frequency group comprises a first test data set of a first switch frequency and a second test data set of a second switch frequency, the first test data set comprises a first power loss, the second test data set comprises a second power loss, and the constructing the target power loss model according to the test data set corresponding to the switch frequency group, the preset conduction loss model and the preset switching loss model comprises: determining a first conduction loss, a first switching loss, a second conduction loss and a second switching loss according to the first power loss and the second power loss; determining a target conduction loss model based on the first conduction loss, the first test data set, the second conduction loss, the second test data set and the preset conduction loss model; determining a target switching loss model based on the first switching loss, the first test data set, the second switching loss, the second test data set and the preset switching loss model; and constructing the target power loss model according to the target conduction loss model and the target switching loss model.

[0011] Based on the above embodiment, the further refined calculation of the switching loss and the conduction loss is completed based on the relationship between the actually collected power loss and different losses under the same switch frequency group, the model construction precision is improved, the hardware requirement for data collection is reduced, and the test cost is effectively controlled.

[0012] In a possible implementation manner of the first aspect, the first switching loss is in a two-fold relationship with the second switching loss, and the determining the first conduction loss, the first switching loss, the second conduction loss and the second switching loss according to the first power loss and the second power loss comprises: obtaining a difference between the first power loss and the second power loss to obtain the second switching loss; obtaining a product of the second switching loss and two to obtain the first switching loss; obtaining a difference between the second power loss and the second switching loss to obtain the second conduction loss; and obtaining a difference between the first power loss and the first switching loss to obtain the first conduction loss.

[0013] In some possible implementation manners, in combination with the first aspect and the foregoing implementation manners, the target parameter types include phase current, power factor, and voltage modulation ratio, the first test data set includes first phase current, first power factor, and first voltage modulation ratio, the second test data set includes second phase current, second power factor, and second voltage modulation ratio, and determining the target conduction loss model based on the first conduction loss, the first test data set, the second conduction loss, the second test data set, and the preset conduction loss model includes: substituting the first phase current, the first power factor, the first voltage modulation ratio, and the corresponding first conduction loss in the same test data group into the preset conduction loss model to obtain a plurality of first conduction loss models; substituting the second phase current, the second power factor, the second voltage modulation ratio, and the corresponding second conduction loss in the same test data group into the preset conduction loss model to obtain a plurality of second conduction loss models; and performing data fitting on the plurality of first conduction loss models and the plurality of second conduction loss models to obtain the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent resistance, and the diode forward conduction equivalent resistance in the preset conduction loss model; and substituting the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent resistance, and the diode forward conduction equivalent resistance into the preset conduction loss model to obtain the target conduction loss model.

[0014] In some possible implementation manners, in combination with the first aspect and the foregoing implementation manners, the target parameter types further include IGBT junction temperature and diode junction temperature, and after obtaining the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent circuit, and the diode forward conduction equivalent resistance in the preset conduction loss model, the method further includes: constructing a first fitting function according to the IGBT initial conduction voltage and the corresponding IGBT junction temperature; constructing a second fitting function according to the IGBT conduction equivalent resistance and the corresponding IGBT junction temperature; constructing a third fitting function according to the diode forward conduction initial voltage and the corresponding diode junction temperature; constructing a fourth fitting function according to the diode forward conduction equivalent resistance and the corresponding diode junction temperature; and determining the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent resistance, and the diode forward conduction equivalent resistance in the target power loss model based on the first fitting function, the second fitting function, the third fitting function, and the fourth fitting function during the operation of the inverter circuit, and determining the actual power loss of the power module based on the adjusted target power loss model.

[0015] Based on the foregoing technical solutions, in actual application, the conduction voltage and the equivalent resistance parameters under different junction temperatures can be obtained by using the equation relationship, the influence of the IGBT power loss and the Doide junction temperature on the parameters is considered, and the IGBT loss accuracy is improved.

[0016] In a possible implementation, the target parameter type includes phase current, DC bus voltage, and switching frequency, the first test data set includes first phase current, first DC bus voltage, and first switching frequency, the second test data set includes second phase current, second DC bus voltage, and second switching frequency, and the determining the target switching loss model based on the first switching loss, the first test data set, the second switching loss, the second test data set, and the preset switching loss model includes: substituting the first phase current, the first DC bus voltage, the first switching frequency, and the corresponding first switching loss in the same test data group into the preset switching loss model to obtain a plurality of first switching loss models; substituting the second phase current, the second DC bus voltage, the second switching frequency, and the corresponding second switching loss in the same test data group into the preset switching loss model to obtain a plurality of second switching loss models; and performing data fitting on the plurality of first switching loss models and the plurality of second switching loss models to obtain a plurality of calculation coefficients in the preset switching loss model, where the plurality of calculation coefficients include a first coefficient corresponding to the phase current, a second coefficient corresponding to the DC bus voltage, a third coefficient corresponding to the switching frequency, and a fourth coefficient corresponding to the product of the phase current and the DC bus voltage; and substituting the plurality of calculation coefficients into the preset switching loss model to obtain the target switching loss model.

[0017] In a second aspect, a loss determination apparatus of a power module is provided, and is applied to an inverter circuit. The apparatus includes: an acquisition module, configured to acquire a preset conduction loss model and a preset switching loss model corresponding to the power module, and determine a target parameter type and at least one switching frequency group according to the preset conduction loss model and the preset switching loss model; a test module, configured to control the power module in the inverter circuit to turn on and turn off based on a switching frequency in the switching frequency group, and acquire a test data set corresponding to the switching frequency during the on-off control, where the test data set includes at least one test data group, and the data type in the test data group corresponds to the target parameter type; and a loss determination module, configured to construct a target power loss model according to the test data set corresponding to the switching frequency group, the preset conduction loss model, and the preset switching loss model, and determine an actual power loss of the power module based on the target power loss model during operation of the inverter circuit.

[0018] In a third aspect, a vehicle is provided, and includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the loss determination method of the power module. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 FIG. 1 is a schematic diagram of an IGBT power loss according to an embodiment of the present application; Figure 2A circuit topology of an inverter circuit provided by an embodiment of the present application is shown in the figure; Figure 3 A flow chart of a loss determination method of a power module provided by an embodiment of the present application is shown in the figure; Figure 4 A flow chart of a loss determination method of a power module provided by an embodiment of the present application is shown in the figure; Figure 5 A connection diagram of a loss determination device of a power module provided by an embodiment of the present application is shown in the figure; Figure 6 A connection diagram of a vehicle provided by an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0020] The technical solutions in the present application will be described in detail below with reference to the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B: "and / or" in the text only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0021] Hereinafter, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more features.

[0022] IGBT has been widely used in new energy electric vehicles, such as bidirectional DC / DC (Direct Current, DC-DC) converter, on-board charger OBC (On-Board Charger, on-board charger), auxiliary drive motor controller, main drive motor controller, etc. IGBT loss, parameters and junction temperature need to be analyzed and protected. As shown in the figure Figure 1 , the IGBT power loss includes the conduction loss and switching loss of the IGBT and the conduction loss and switching loss of the anti-parallel diode. Among them, the switching loss is the energy loss generated by the voltage and current overlap in the switching transient process, including the turn-on loss and turn-off loss, which directly affects the device selection and system efficiency; the conduction loss is the loss caused by the on-state voltage drop and current when the power tube is in the conduction state.

[0023] In the related art, the switching and conduction losses of an IGBT are obtained by an IGBT single / dual pulse test method. Specifically, the single / dual pulse test is usually tested in a half-bridge form. The so-called single / dual pulse is that the upper tube remains off, and the lower tube is driven to give a single / dual pulse to test the gate charge of the IGBT. The conduction delay time, rise time, turn-off delay time, fall time, turn-on loss, turn-off loss, reverse recovery current, reverse recovery time, and reverse recovery energy are tested, so as to calculate the switching and conduction losses of the IGBT. In the loss calculation of the IGBT, IGBT-related parameters are used. These parameters are obtained by building an IGBT single / dual pulse test based on hardware design. The motor drive controller hardware and topology need to be modified. The normal motor controller topology is as follows: Figure 2 The single / dual pulse test method is affected by factors such as hardware equipment, environmental temperature, and experimental power topology structure, which brings deviation. At the same time, the single / dual pulse test is very complex and time-consuming, which increases the application cost.

[0024] To solve at least one of the above technical problems, the present application provides a power module loss determination method. The method can build a target power loss model based on an actual application scenario after the inverter circuit is built, thereby improving the power loss calculation accuracy in the application process and ensuring the operation effect of the actual circuit.

[0025] The power module loss determination method of the present application will be described in detail below with reference to the accompanying drawings.

[0026] In an embodiment of the present application, the power module loss determination method is applied to an inverter circuit.

[0027] Specifically, in the embodiment shown in Figure 2 The inverter circuit is a three-phase full-bridge inverter circuit for generating three-phase current (Iu, Iv, Iw) to drive a permanent magnet synchronous motor (PMSM) to operate. The corresponding DC bus voltage is Udc. The inverter circuit includes six power modules composed of IGBTs and anti-parallel diodes.

[0028] In combination with Figure 3 The power module loss determination method of the present application includes the following steps: S1, obtaining a preset conduction loss model and a preset switching loss model corresponding to the power module, and determining a target parameter type and at least one switching frequency group according to the preset conduction loss model and the preset switching loss model.

[0029] Specifically, the preset conduction loss model and the preset switching loss model can be determined according to a specific circuit in which the power module is located, wherein the preset conduction loss model includes IGBT conduction loss and diode conduction loss, and the preset switching loss model includes IGBT switching loss and diode switching loss. The target parameter type is determined according to the loss correlation in the preset conduction loss model and the preset switching loss model, and the switching frequency group is determined according to the parameter type that needs to be indirectly obtained by mutual cooperation in the preset conduction loss model and the preset switching loss model. There is a corresponding data relationship in the switching frequency in the switching frequency group in the loss calculation process, and the data under different switching frequencies in the switching frequency group are jointly collected to ensure the successful fitting calculation of the preset conduction loss model and the preset switching loss model.

[0030] S2, the switching frequency in the switching frequency group is used to control the on-off of the power module in the inverter circuit, and in the on-off control process, a test data set corresponding to the switching frequency is obtained, wherein the test data set includes at least one test data group, and the data type in the test data group corresponds to the target parameter type.

[0031] Specifically, in Figure 2 In the embodiment shown, the motor drive controller can be connected to the power bench, and the power analyzer can be connected to the power bench. The power analyzer can output IGBT power loss. Since the IGBT power loss is related to the DC bus voltage, the phase current and the IGBT switching frequency, the target parameter type can be set as the DC bus voltage, the phase current, the IGBT switching frequency, etc.

[0032] Then, during calibration, each phase current (the phase current change rule can be: every interval 100A to the maximum phase current, 100A, 200A, IsMax), DC bus voltage (the change rule of the DC bus voltage can be: minimum operating voltage, rated voltage and maximum operating voltage) and switching frequency (the main use switching frequency of the motor controller is 3-12kHz switching frequency, so the switching frequency can be 5kHz and 10kHz) are traversed, and the power analyzer records the IGBT power loss. Specifically, the test data set of the switching frequency 5kHz and 10kHz shown in Table 1 can be obtained.

[0033] Table 1

[0034] S3, the target power loss model is constructed according to the test data set corresponding to the switching frequency group, the preset conduction loss model and the preset switching loss model, so that the actual power loss of the power module can be determined based on the target power loss model during the operation of the inverter circuit.

[0035] Specifically, taking the switching frequency group including 5 kHz and 10 kHz as an example, the switching frequency group corresponds to a test data set including a test data set of 5 kHz and a test data set of 10 kHz.

[0036] The test data set of 5 kHz and the test data set of 10 kHz are substituted into the preset conduction loss model and the preset switching loss model, the model parameters in the preset conduction loss model and the preset switching loss model are calculated through data fitting, and then the calculated model parameters are substituted into the preset conduction loss model and the preset switching loss model to obtain a target power loss model. Then, during the operation of the inverter circuit, the corresponding parameters of the real-time acquired operating parameters such as phase current, DC bus voltage and switching frequency can be substituted into the target power loss model, so as to accurately obtain the power loss of the IGBT.

[0037] This embodiment builds a target power loss model based on an actual application scenario after the inverter circuit is constructed, improves the simplicity, speed and reliability of IGBT loss and parameter calibration, does not need to perform single-pulse and double-pulse tests on the inverter, solves the problems of complex IGBT loss calculation of the inverter in the motor drive control system and the accuracy problem caused by external factors such as temperature equipment.

[0038] In some embodiments of the present application, the power module includes an IGBT and a diode in reverse parallel connection, and the preset conduction loss model and the preset switching loss model corresponding to the power module are obtained by: determining a first conduction loss model and a first switching loss model corresponding to the IGBT; determining a second conduction loss model and a second switching loss model corresponding to the diode; determining the preset conduction loss model according to the first conduction loss model and the second conduction loss model; and determining the preset switching loss model according to the first switching loss model and the second switching loss model.

[0039] Specifically, taking the switching frequency group including 5 kHz and 10 kHz as an example, the switching frequency group corresponds to a test data set including a test data set of 5 kHz and a test data set of 10 kHz. Figure 2 The value of the conduction loss actually sampled and acquired is the sum of the IGBT conduction loss and the diode conduction loss, that is, the IGBT conduction loss model formula (the first conduction loss model) and the diode conduction loss model formula (the second conduction loss model) are added to equal the preset conduction loss model, and the formula is as follows: The conduction loss formula of the IGBT based on the electrical period, that is, the formula of the first conduction loss model, is as follows: (1) Among them, .

[0040] The calculation formula of the second conduction loss model is as follows: (2) Then, the formula of the preset conduction loss model is as follows: Conduction loss + (3) wherein, represents the IGBT conduction loss; represents the diode conduction loss; Is represents the phase current value; represents the power factor angle; cos represents the power factor, and m represents the voltage modulation ratio.

[0041] The average switching loss is the average loss in a period of time, which is proportional to the switching frequency. Therefore, the switching loss is related to the voltage, current and switching frequency. According to the known IGBT turn-on and turn-off process curve, the switching loss is linearly related to the voltage and current, and finally positively related to the total switching frequency. Assuming that the fitting switching loss model formula is as follows, and is a correlation coefficient.

[0042] wherein, the formula of the first switching loss model is as follows: (4) The formula of the second switching loss model is as follows: (5) Then, the calculation formula of the preset switching loss model is: Switching loss (6) In the above formula: represents the IGBT switching loss; represents the diode switching loss; Fswt represents the switching frequency; Is represents the phase current value; udc represents the DC bus voltage.

[0043] The embodiment respectively constructs the conduction loss model and the switching loss model of the IGBT, and the conduction loss model and the switching loss model of the diode, and then constructs the preset conduction loss model and the preset switching loss model based on the above four model formulas, thereby improving the model construction precision.

[0044] In some embodiments of the present application, the switching frequency group includes a first switching frequency and a second switching frequency. Under the same current and voltage test working conditions, the first switching loss corresponding to the first switching frequency is greater than the second switching loss corresponding to the second switching frequency, and the first switching loss and the second switching loss have a multiple relationship. The first conduction loss corresponding to the first switching frequency is equal to the second conduction loss corresponding to the second switching frequency.

[0045] For example, the switching loss (the sum of IGBT and Diode switching loss) of 10 kHz and 5 kHz switching frequency under the same voltage and current condition has the following relationship: 2*5HKZ switching loss = 10KHZ switching loss. The related parameters (Vce0, Vf0, Rce and Rf) involved in the conduction loss model formula are basically the same at 5 KHZ and 10 KHZ, that is, the conduction loss of 5 KHZ and 10 KHZ is the same, so the switching frequency group includes 5 kHz and 10 kHz switching frequency.

[0046] That is, under the same current and voltage condition, the switching loss of 10 KHZ is equal to 2 times the switching loss of 5 KHZ, and the conduction losses of the two are the same. That is, the difference between the IGBT power loss of 10 KHZ and the IGBT power loss of 5 KHZ under a certain same voltage and current is the switching loss of 5 KHZ under the voltage and current. The IGBT power loss minus the switching loss is the conduction loss. Therefore, according to the IGBT power loss collected under 10 KHZ and 5 KHZ of the switching frequency group, and by calculating the corresponding switching loss and conduction loss, the data fitting calculation requirement can be met, and the model construction accuracy is ensured.

[0047] In some embodiments of the present application, the target parameter type includes the power loss of the power module, the test data set corresponding to the switching frequency group includes a first test data set of a first switching frequency and a second test data set of a second switching frequency, the first test data set includes a first power loss, and the second test data set includes a second power loss. The target power loss model is constructed according to the test data set corresponding to the switching frequency group, the preset conduction loss model and the preset switching loss model, which includes: determining a first conduction loss, a first switching loss, a second conduction loss and a second switching loss according to the first power loss and the second power loss; determining a target conduction loss model based on the first conduction loss, the first test data set, the second conduction loss, the second test data set and the preset conduction loss model; determining a target switching loss model based on the first switching loss, the first test data set, the second switching loss, the second test data set and the preset switching loss model; and constructing the target power loss model according to the target conduction loss model and the target switching loss model.

[0048] Specifically, since they are under the same switching frequency group, the first switching loss and the second switching loss collected under the same current and voltage condition have a multiple relationship, and the first conduction loss and the second conduction loss are equal, and the power loss = switching loss + conduction loss. Therefore, based on the collected first power loss and second power loss, the first switching loss corresponding to the first switching frequency, the first conduction loss, and the second switching loss and the second conduction loss corresponding to the second switching frequency can be calculated respectively.

[0049] Then, the first conduction loss, the first test data set, the second conduction loss, the second test data set are substituted into the preset conduction loss model respectively to solve the model parameters in the preset conduction loss model, and a target conduction loss model is obtained. The first switching loss, the first test data set, the second switching loss, and the second test data set are substituted into the preset switching loss model respectively to solve the model parameters in the preset switching loss model, and a target switching loss model is obtained. The formula of the target conduction loss model and the formula of the target switching loss model are taken as the formula of the target power loss model.

[0050] This embodiment combines the relationship between the actually collected power loss and different losses under the same switching frequency group to complete further refined calculation of the switching loss and the conduction loss, improves the model construction accuracy, reduces the hardware demand for data collection, and effectively controls the test cost.

[0051] In some embodiments of the present application, the first switching loss and the second switching loss have a two-fold relationship, and the first conduction loss, the first switching loss, the second conduction loss, and the second switching loss are determined according to the first power loss and the second power loss, including: obtaining the difference between the first power loss and the second power loss to obtain the second switching loss; obtaining the product of the second switching loss and two to obtain the first switching loss; obtaining the difference between the second power loss and the second switching loss to obtain the second conduction loss; and obtaining the difference between the first power loss and the first switching loss to obtain the first conduction loss.

[0052] That is, the conduction loss and the switching loss under the first switching frequency and the second switching frequency are calculated based on the following formula, which greatly reduces the calculation cost, and the specific formula is: Second switching loss = first power loss-second power loss; Second conduction loss = second power loss-second switching loss; First switching loss = second switching loss*2; First conduction loss = first power loss-first switching loss.

[0053] In some embodiments of the present application, the target parameter type includes phase current, power factor and voltage modulation ratio, the first test data set includes first phase current, first power factor and first voltage modulation ratio, the second test data set includes second phase current, second power factor and second voltage modulation ratio, and the target conduction loss model is determined based on the first conduction loss, the first test data set, the second conduction loss, the second test data set and the preset conduction loss model, including: substituting the first phase current, the first power factor, the first voltage modulation ratio and the corresponding first conduction loss in the same test data group into the preset conduction loss model to obtain a plurality of first conduction loss models; substituting the second phase current, the second power factor, the second voltage modulation ratio and the corresponding second conduction loss in the same test data group into the preset conduction loss model to obtain a plurality of second conduction loss models; performing data fitting on the plurality of first conduction loss models and the plurality of second conduction loss models to obtain IGBT initial conduction voltage, diode forward conduction initial voltage, IGBT conduction equivalent resistance and diode forward conduction equivalent resistance in the preset conduction loss model; and substituting the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent resistance and the diode forward conduction equivalent resistance into the preset conduction loss model to obtain the target conduction loss model.

[0054] Specifically, after the motor drive system bench completes full MAP scanning of phase current, DC bus voltage and switching frequency according to Table 1, the corresponding phase current, power factor and voltage modulation ratio under the working condition are substituted into the above-mentioned preset conduction loss model formula, and the related parameters (Vce0, Vf, Rce, Rf) in the IGBT power loss are calculated by fitting and approximately solving the formula, wherein Vce0 is the initial conduction voltage of the collector-emitter of the IGBT, Vf is the initial forward conduction voltage of the anti-parallel diode, Rce is the conduction equivalent resistance of the collector-emitter of the IGBT, and Rf is the forward conduction equivalent resistance of the anti-parallel diode. Thus, the parameters in the preset conduction loss model are solved, which are brought into the preset conduction loss model to construct the target conduction loss model, thereby ensuring the construction accuracy of the target conduction loss model.

[0055] In some embodiments of the present application, the target parameter type further includes IGBT junction temperature and diode junction temperature, and after obtaining the IGBT initial conduction voltage, diode forward conduction initial voltage, IGBT conduction equivalent circuit and diode forward conduction equivalent resistance in the preset conduction loss model, the method further comprises: constructing a first fitting function according to the IGBT initial conduction voltage and the corresponding IGBT junction temperature; constructing a second fitting function according to the IGBT conduction equivalent resistance and the corresponding IGBT junction temperature; constructing a third fitting function according to the diode forward conduction initial voltage and the corresponding diode junction temperature; constructing a fourth fitting function according to the diode forward conduction equivalent resistance and the corresponding diode junction temperature; during the operation of the inverter circuit, determining the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent resistance and the diode forward conduction equivalent resistance in the target power loss model based on the first fitting function, the second fitting function, the third fitting function and the fourth fitting function, and determining the actual power loss of the power module based on the adjusted target power loss model.

[0056] That is, considering that the conduction voltage and equivalent resistance parameters (Vce0, Vf, Rce and Rf) involved in the target conduction loss model formula are related to the junction temperature of IGBT and Diode (diode in anti-parallel with IGBT), the junction temperature of IGBT and Diode is measured by using a thermal imager, and the junction temperature of each working condition is recorded. According to the recorded junction temperature and corresponding Vce0, Vf, Rce and Rf parameters under different working conditions, the conduction voltage and equivalent resistance parameters of IGBT / Doide can be related to the junction temperature in a first order equation. Thus, in actual application, the conduction voltage and equivalent resistance parameters under different junction temperatures are obtained by using the equation relationship, considering the influence of IGBT power loss and Doide junction temperature on the parameters, thereby improving the IGBT loss accuracy. Among them, the controller and IGBT junction temperature change code IGBT parameter change and loss deviation can be tested and calibrated by the thermal imager to improve the accuracy.

[0057] In some embodiments of the present application, the target parameter type includes phase current, DC bus voltage, switching frequency, the first test data set includes first phase current, first DC bus voltage and first switching frequency, the second test data set includes second phase current, second DC bus voltage and second switching frequency, and the target switching loss model is determined based on the first switching loss, the first test data set, the second switching loss, the second test data set and the preset switching loss model. The method comprises: substituting the first phase current, the first DC bus voltage, the first switching frequency and the corresponding first switching loss in the same test data group into the preset switching loss model to obtain a plurality of first switching loss models; substituting the second phase current, the second DC bus voltage, the second switching frequency and the corresponding second switching loss in the same test data group into the preset switching loss model to obtain a plurality of second switching loss models; and performing data fitting on the plurality of first switching loss models and the plurality of second switching loss models to obtain a plurality of calculation coefficients in the preset switching loss model, wherein the plurality of calculation coefficients include a first coefficient corresponding to the phase current, a second coefficient corresponding to the DC bus voltage, a third coefficient corresponding to the switching frequency, and a fourth coefficient corresponding to the product of the phase current and the DC bus voltage; and substituting the plurality of calculation coefficients into the preset switching loss model to obtain the target switching loss model.

[0058] Specifically, according to the value of the switching loss obtained on the test bench, that is, the sum of the IGBT switching loss and the diode switching loss, that is, adding the IGBT switching loss and the diode switching loss model formula, the collected phase current value, DC bus voltage and switching loss data are fitted by a Matlab script to obtain the coefficients Asw and Bsw between the switching loss and the voltage and current and the switching frequency, which are brought into the preset switching loss model to obtain the target conduction loss model, thereby ensuring the model construction accuracy.

[0059] Therefore, the technical scheme firstly obtains the MAP data of the switching loss (the sum of the IGBT and Diode switching losses) and the conduction loss (the sum of the IGBT and Diode conduction losses) under a certain current and voltage at a specific switching frequency (for example, 5KHZ and 10KHZ) on the power test bench, and brings the MAP data into the model formula of the IGBT and Diode switching loss and conduction loss to obtain the related parameters in the model formula, that is, Vce0, Vf0, Rce, Rf, A_sw and B_sw. Finally, the full MAP data obtained on the test bench and the related parameters (Vce0, Vf0, Rce, Rf, A_sw and B_sw) are written to the software system of the real vehicle, and the current, voltage and switching frequency under the current working condition are retrieved and brought into the model formula of the switching loss and conduction loss to obtain the IGBT power loss under the current working condition in the actual operation of the vehicle.

[0060] As one specific implementation of the present application Figure 4 As shown in the foregoing description, before making the loss calibration of the IGBT, the basic software in the motor controller can record the phase current, bus voltage, switching frequency, power factor and modulation ratio and other data through the communication software tool before making the loss calibration of the IGBT; the calibration method is to traverse each phase current (every interval of 100A to the maximum phase current, 100A, 200A, IsMax), bus voltage (minimum operating voltage, rated voltage and maximum operating voltage) and switching frequency (the main use switching frequency of the motor controller is 3-12 kHz switching frequency, and 5 kHz and 10 kHz are preferred), and record the related data of the controller. The thermal imager measures the junction temperature of the IGBT black module irradiating the IGBT and Diode and records the junction temperature of each working condition (the on-voltage drop and equivalent impedance parameters of the IGBT / Doide have a first-order equation relationship with the junction temperature).

[0061] Specifically, taking the test using one switching frequency group as an example, the switching frequency group includes 5 kHz and 10 kHz switching frequencies. First, environmental calibration is performed: 2000Rpm fixed speed, Is mode FOC (Field-Oriented Control, magnetic field oriented control) control operation, that is, the motor is controlled to operate at a speed of 2000 revolutions per minute, and the Is mode means that the main target of the controller is to maintain the amplitude of the motor stator total current (Is) as a constant value. Then, the control method of the bus voltage, switching frequency and phase current shown in Table 1 is used to perform operation test under different working conditions, and the corresponding data are recorded, including: inverter loss Ptotal obtained by the bench power analyzer, IGBT and Diode junction temperature; voltage modulation ratio m and phase current Is corresponding to the electric control software, and motor power factor cos Then, the on-state loss and switching loss of the output 5 kHz and 10 kHz are calculated respectively. The IGBT and the anti-parallel diode are not simultaneously turned on in the FOC operation control, and all the on-voltage and equivalent resistance are calculated according to the basic solution output. According to the parameter curve given in the IGBT module manual, the on-voltage and equivalent resistance distribution ratio of the IGBT and the anti-parallel Diode can be calculated respectively, and the switching loss fitting coefficient ratio of the IGBT and the anti-parallel Diode can also be obtained according to the turn-on and turn-off energy ratio given in the IGBT module manual. Finally, Vce0 and Vf0 voltage and Rce and Rf on-state equivalent resistance, and , , , , , , and Finally, all the parameters are substituted into the loss model of the IGBT and Diode, and the real-time power loss can be calculated.

[0062] The IGBT power loss calculation and calibration method determined by the embodiment of the application does not need to modify the motor drive controller hardware and topology, directly uses the normal motor controller to do FOC motor drive control calibration on the power bench, is simple and convenient, saves experiment environment building time and test time, and the single and double pulse test working conditions are very many and complex; the controller and IGBT junction temperature change code IGBT parameter change and loss deviation can be tested and calibrated by a thermal imager, and the precision is improved.

[0063] To sum up, the power module loss determination method of the embodiment of the application, after the inverter circuit is constructed by the power module, acquires the preset conduction loss model and the preset switching loss model corresponding to the power module, determines the target parameter type and at least one switching frequency group according to the preset conduction loss model and the preset switching loss model, then controls the on-off of the power module in the inverter circuit based on the switching frequency in the switching frequency group, and in the on-off control process, acquires the test data set corresponding to the switching frequency, wherein the test data set includes at least one test data group, the data type in the test data group corresponds to the target parameter type, and according to the test data set corresponding to the switching frequency group, the preset conduction loss model and the preset switching loss model, a target power loss model is constructed to determine the actual power loss of the power module based on the target power loss model in the operation process of the inverter circuit. Therefore, the method can construct the target power loss model based on the actual application scene after the inverter circuit is constructed, thereby improving the power loss calculation precision in the application process and guaranteeing the operation effect of the actual circuit.

[0064] Figure 5 is a structural schematic diagram of a power module loss determination device provided by the embodiment of the application.

[0065] Exemplarily, as Figure 5 shown, the power module loss determination device is applied to an inverter circuit and can include: The acquisition module 10 is configured to acquire the preset conduction loss model and the preset switching loss model corresponding to the power module, and determine the target parameter type and at least one switching frequency group according to the preset conduction loss model and the preset switching loss model. The test module 20 is configured to control the on-off of the power module in the inverter circuit based on the switching frequency in the switching frequency group, and in the on-off control process, acquire the test data set corresponding to the switching frequency, wherein the test data set includes at least one test data group, and the data type in the test data group corresponds to the target parameter type. The loss determination module 30 is configured to construct a target power loss model according to the test data set corresponding to the switch frequency group, the preset conduction loss model and the preset switching loss model, so as to determine the actual power loss of the power module based on the target power loss model during the operation of the inverter circuit.

[0066] In some embodiments of the present application, the power module includes an IGBT and a diode in anti-parallel connection, the acquisition module 10 acquires the preset conduction loss model and the preset switching loss model corresponding to the power module, and is specifically configured to: determine a first conduction loss model and a first switching loss model corresponding to the IGBT; determine a second conduction loss model and a second switching loss model corresponding to the diode; determine the preset conduction loss model according to the first conduction loss model and the second conduction loss model; and determine the preset switching loss model according to the first switching loss model and the second switching loss model.

[0067] In some embodiments of the present application, the switch frequency group includes a first switch frequency and a second switch frequency, and under the same test working condition of current and voltage, a first switching loss corresponding to the first switch frequency is greater than a second switching loss corresponding to the second switch frequency, and the first switching loss and the second switching loss have a multiple relationship, and a first conduction loss corresponding to the first switch frequency is equal to a second conduction loss corresponding to the second switch frequency.

[0068] In some embodiments of the present application, the target parameter type includes a power loss of the power module, the test data set corresponding to the switch frequency group includes a first test data set of a first switch frequency and a second test data set of a second switch frequency, the first test data set includes a first power loss, and the second test data set includes a second power loss, and the loss determination module 30 constructs the target power loss model according to the test data set corresponding to the switch frequency group, the preset conduction loss model and the preset switching loss model, and is specifically configured to: determine a first conduction loss, a first switching loss, a second conduction loss and a second switching loss according to the first power loss and the second power loss; determine a target conduction loss model based on the first conduction loss, the first test data set, the second conduction loss, the second test data set and the preset conduction loss model; determine a target switching loss model based on the first switching loss, the first test data set, the second switching loss, the second test data set and the preset switching loss model; and construct the target power loss model according to the target conduction loss model and the target switching loss model.

[0069] In some embodiments of the present application, the first switching loss is in a two-fold relationship with the second switching loss, and the loss determination module 30 determines the first conduction loss, the first switching loss, the second conduction loss and the second switching loss according to the first power loss and the second power loss, specifically for: obtaining the difference between the first power loss and the second power loss to obtain the second switching loss; obtaining the product of the second switching loss and two to obtain the first switching loss; obtaining the difference between the second power loss and the second switching loss to obtain the second conduction loss; obtaining the difference between the first power loss and the first switching loss to obtain the first conduction loss.

[0070] In some embodiments of the present application, the target parameter type includes phase current, power factor and voltage modulation ratio, the first test data set includes first phase current, first power factor and first voltage modulation ratio, the second test data set includes second phase current, second power factor and second voltage modulation ratio, and the loss determination module 30 determines the target conduction loss model based on the first conduction loss, the first test data set, the second conduction loss, the second test data set and the preset conduction loss model, specifically for: substituting the first phase current, the first power factor, the first voltage modulation ratio and the corresponding first conduction loss in the same test data group into the preset conduction loss model to obtain a plurality of first conduction loss models; substituting the second phase current, the second power factor, the second voltage modulation ratio and the corresponding second conduction loss in the same test data group into the preset conduction loss model to obtain a plurality of second conduction loss models; data fitting is performed on the plurality of first conduction loss models and the plurality of second conduction loss models to obtain the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent resistance and the diode forward conduction equivalent resistance in the preset conduction loss model; and substituting the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent resistance and the diode forward conduction equivalent resistance into the preset conduction loss model to obtain the target conduction loss model.

[0071] In some embodiments of the present application, the target parameter type further includes IGBT junction temperature and diode junction temperature, and after obtaining the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent circuit and the diode forward conduction equivalent resistance in the preset conduction loss model, the loss determination module 30 is further configured to: construct a first fitting function according to the IGBT initial conduction voltage and the corresponding IGBT junction temperature; construct a second fitting function according to the IGBT conduction equivalent resistance and the corresponding IGBT junction temperature; construct a third fitting function according to the diode forward conduction initial voltage and the corresponding diode junction temperature; construct a fourth fitting function according to the diode forward conduction equivalent resistance and the corresponding diode junction temperature; determine the IGBT initial conduction voltage, the diode forward conduction initial voltage, the IGBT conduction equivalent resistance and the diode forward conduction equivalent resistance in the target power loss model based on the first fitting function, the second fitting function, the third fitting function and the fourth fitting function during the operation of the inverter circuit, and determine the actual power loss of the power module based on the adjusted target power loss model.

[0072] In some embodiments of the present application, the target parameter type includes phase current, DC bus voltage and switching frequency, the first test data set includes first phase current, first DC bus voltage and first switching frequency, the second test data set includes second phase current, second DC bus voltage and second switching frequency, and the loss determination module 30 determines the target switching loss model based on the first switching loss, the first test data set, the second switching loss, the second test data set and the preset switching loss model, and is specifically configured to: substitute the first phase current, the first DC bus voltage, the first switching frequency and the corresponding first switching loss in the same test data group into the preset switching loss model to obtain a plurality of first switching loss models; substitute the second phase current, the second DC bus voltage, the second switching frequency and the corresponding second switching loss in the same test data group into the preset switching loss model to obtain a plurality of second switching loss models; and perform data fitting on the plurality of first switching loss models and the plurality of second switching loss models to obtain a plurality of calculation coefficients in the preset switching loss model, wherein the plurality of calculation coefficients include a first coefficient corresponding to the phase current, a second coefficient corresponding to the DC bus voltage, a third coefficient corresponding to the switching frequency and a fourth coefficient corresponding to the product of the phase current and the DC bus voltage; and substitute the plurality of calculation coefficients into the preset switching loss model to obtain the target conduction loss model.

[0073] Figure 6 A structural schematic diagram of a vehicle is provided for the embodiments of the present application. The vehicle can include: The memory 301, the processor 302 and the computer program stored in the memory 301 and executable on the processor 302.

[0074] The processor 302 implements the loss determination method of the power module provided in the above embodiments when executing a program.

[0075] Further, the vehicle further comprises: The communication interface 303 is configured to communicate between the memory 301 and the processor 302.

[0076] The memory 301 is configured to store a computer program executable in the processor 302.

[0077] The memory 301 can include a high-speed RAM (Random Access Memory) memory, and can further include a nonvolatile memory, for example, at least one disk memory.

[0078] If the memory 301, the processor 302 and the communication interface 303 are independently implemented, the communication interface 303, the memory 301 and the processor 302 can be connected through a bus and communicate with each other. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, Figure 6 In the figure, only one thick line is used to represent the bus, but it does not mean that there is only one bus or only one type of bus.

[0079] Optionally, in a specific implementation, if the memory 301, the processor 302 and the communication interface 303 are integrated on a chip, the memory 301, the processor 302 and the communication interface 303 can communicate with each other through an internal interface.

[0080] The processor 302 can be a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application.

[0081] In addition, the terms "first", "second", etc. are used only to describe the purpose and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited.

[0082] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms is not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, the person skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0083] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and cannot be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A method for determining the losses of a power module, characterized in that, Applied to inverter circuits, the method includes: Obtain the preset conduction loss model and preset switching loss model corresponding to the power module, and determine the target parameter type and at least one switching frequency group based on the preset conduction loss model and the preset switching loss model; The power module in the inverter circuit is switched on and off based on the switching frequency in the switching frequency group, and a test data set corresponding to the switching frequency is acquired during the switching control process. The test data set includes at least one test data group, and the data type in the test data group corresponds to the target parameter type. A target power loss model is constructed based on the test data set corresponding to the switching frequency group, the preset conduction loss model, and the preset switching loss model, so as to determine the actual power loss of the power module based on the target power loss model during the operation of the inverter circuit.

2. The method for determining the loss of a power module according to claim 1, characterized in that, The power module includes an IGBT and a diode connected in anti-parallel. Obtaining the preset conduction loss model and preset switching loss model corresponding to the power module includes: Determine the first conduction loss model and the first switching loss model corresponding to the IGBT; Determine the second conduction loss model and the second switching loss model corresponding to the diode; The preset conduction loss model is determined based on the first conduction loss model and the second conduction loss model; The preset switching loss model is determined based on the first switching loss model and the second switching loss model.

3. The method for determining the loss of a power module according to claim 1 or 2, characterized in that, The switching frequency group includes a first switching frequency and a second switching frequency. Under the same current and voltage test conditions, the first switching loss corresponding to the first switching frequency is greater than the second switching loss corresponding to the second switching frequency, and the first switching loss and the second switching loss are in a multiple relationship. The first conduction loss corresponding to the first switching frequency is equal to the second conduction loss corresponding to the second switching frequency.

4. The method for determining the loss of a power module according to claim 3, characterized in that, The target parameter type includes the power loss of the power module. Based on the test data set corresponding to the switching frequency group, which includes a first test data set for the first switching frequency and a second test data set for the second switching frequency, the first test data set includes a first power loss, and the second test data set includes a second power loss. A target power loss model is constructed based on the test data set corresponding to the switching frequency group, the preset conduction loss model, and the preset switching loss model, including: The first conduction loss, the first switching loss, the second conduction loss, and the second switching loss are determined based on the first power loss and the second power loss. The target conduction loss model is determined based on the first conduction loss, the first test data set, the second conduction loss, the second test data set, and the preset conduction loss model. The target switching loss model is determined based on the first switching loss, the first test data set, the second switching loss, the second test data set, and the preset switching loss model; The target power loss model is constructed based on the target conduction loss model and the target switching loss model.

5. The method for determining the loss of a power module according to claim 4, characterized in that, The first switching loss is twice the second switching loss. The first conduction loss, the first switching loss, the second conduction loss, and the second switching loss are determined based on the first power loss and the second power loss, including: The difference between the first power loss and the second power loss is obtained to obtain the second switching loss; The first switching loss is obtained by multiplying the second switching loss by two. The difference between the second power loss and the second switching loss is obtained to obtain the second conduction loss; The difference between the first power loss and the first switching loss is obtained to obtain the first conduction loss.

6. The method for determining the loss of a power module according to claim 4, characterized in that, The target parameter types include phase current, power factor, and voltage modulation ratio. The first test data set includes the first phase current, the first power factor, and the first voltage modulation ratio. The second test data set includes the second phase current, the second power factor, and the second voltage modulation ratio. A target conduction loss model is determined based on the first conduction loss, the first test data set, the second conduction loss, the second test data set, and the preset conduction loss model, including: Substitute the first phase current, first power factor, first voltage modulation ratio, and corresponding first conduction loss in the same test data group into the preset conduction loss model to obtain multiple first conduction loss models. Substitute the second phase current, second power factor, second voltage modulation ratio, and corresponding second conduction loss in the same test data group into the preset conduction loss model to obtain multiple second conduction loss models. Data fitting is performed on multiple first conduction loss models and multiple second conduction loss models to obtain the IGBT initial conduction voltage, diode forward conduction initial voltage, IGBT conduction equivalent resistance, and diode forward conduction equivalent resistance in the preset conduction loss model; Substitute the initial conduction voltage of the IGBT, the initial forward conduction voltage of the diode, the equivalent conduction resistance of the IGBT, and the equivalent forward conduction resistance of the diode into the preset conduction loss model to obtain the target conduction loss model.

7. The loss determination method according to claim 6, characterized in that, The target parameter types also include IGBT junction temperature and diode junction temperature. After obtaining the IGBT initial conduction voltage, diode forward conduction initial voltage, IGBT conduction equivalent circuit, and diode forward conduction equivalent resistance in the preset conduction loss model, it also includes: A first fitting function is constructed based on the initial on-voltage of the IGBT and the corresponding junction temperature of the IGBT. A second fitting function is constructed based on the IGBT on-equivalent resistance and the corresponding IGBT junction temperature. A third fitting function is constructed based on the initial forward voltage of the diode and the corresponding diode junction temperature. A fourth fitting function is constructed based on the diode's forward conduction equivalent resistance and the corresponding diode junction temperature; During the operation of the inverter circuit, the initial on-state voltage of the IGBT, the initial on-state voltage of the diode, the equivalent on-state resistance of the IGBT, and the equivalent on-state resistance of the diode in the target power loss model are determined based on the first fitting function, the second fitting function, the third fitting function, and the fourth fitting function. The actual power loss of the power module is then determined based on the adjusted target power loss model.

8. The method for determining the loss of a power module according to claim 4, characterized in that, The target parameter types include phase current, DC bus voltage, and switching frequency. The first test data set includes the first phase current, the first DC bus voltage, and the first switching frequency. The second test data set includes the second phase current, the second DC bus voltage, and the second switching frequency. A target switching loss model is determined based on the first switching loss, the first test data set, the second switching loss, the second test data set, and the preset switching loss model, including: Substitute the first phase current, first DC bus voltage, first switching frequency, and corresponding first switching loss in the same test data group into the preset switching loss model to obtain multiple first switching loss models. Substitute the second phase current, second DC bus voltage, second switching frequency, and corresponding second switching loss in the same test data group into the preset switching loss model to obtain multiple second switching loss models. Data fitting is performed on multiple first switching loss models and multiple second switching loss models to obtain multiple calculated coefficients in the preset switching loss model. The multiple calculated coefficients include a first coefficient corresponding to the phase current, a second coefficient corresponding to the DC bus voltage, a third coefficient corresponding to the switching frequency, and a fourth coefficient corresponding to the product of the phase current and the DC bus. Substitute the calculated coefficients into the preset switching loss model to obtain the target conduction loss model.

9. A power module loss determination device, characterized in that, The device, applied to an inverter circuit, includes: The acquisition module is used to acquire the preset conduction loss model and the preset switching loss model corresponding to the power module, and determine the target parameter type and at least one switching frequency group based on the preset conduction loss model and the preset switching loss model; The test module is used to control the power module in the inverter circuit to switch on and off based on the switching frequency in the switching frequency group, and to acquire a test data set corresponding to the switching frequency during the switching control process. The test data set includes at least one test data group, and the data type in the test data group corresponds to the target parameter type. The loss determination module is used to construct a target power loss model based on the test data set corresponding to the switching frequency group, the preset conduction loss model, and the preset switching loss model, so as to determine the actual power loss of the power module based on the target power loss model during the operation of the inverter circuit.

10. A vehicle, characterized in that, The vehicle includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the power module loss determination method as described in any one of claims 1-8.

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