Method, device, equipment and storage medium for predicting junction temperature of power module in inverter

Abstract

An embodiment of the present invention provides a method, device, equipment and storage medium for predicting the junction temperature of a power module in an inverter, relating to the technical field of power module junction temperature prediction. The method includes: obtaining the working parameter information of the inverter and the working parameter information of the motor; obtaining the vector control model of the motor, and determining the switching state information of the power module according to the working parameter information of the inverter, the working parameter information of the motor and the vector control model of the motor; determining the power loss of the power module within a unit switching period according to the working parameter information of the inverter, the working parameter information of the motor and the switching state information of the power module; obtaining the thermal resistance network model of the power module, and predicting the junction temperature of the power module in the corresponding unit switching period according to the power loss of the power module within a unit switching period and the thermal resistance network model of the power module. The present invention can accurately predict the dynamic junction temperature of the power module in any switching period within any electrical cycle.

Description

Technical Field

[0001] The present invention relates to the technical field of power module junction temperature prediction, and specifically relates to a method for predicting the junction temperature of a power module in an inverter, a device for predicting the junction temperature of a power module in an inverter, a terminal device, and a computer storage medium. Background Art

[0002] The power module in an inverter is an important execution part for implementing motor control. The power module, such as an IGBT (Insulated Gate Bipolar Transistor) module, generates a large amount of heat loss during operation, causing the temperature (junction temperature) at the chip PN junction to rise and fluctuate. When the junction temperature exceeds a certain limit, it will lead to the failure of the IGBT module. Therefore, accurately predicting the operating junction temperature of the power module is beneficial to guiding the design of the inverter to ensure the stable operation of the inverter. However, currently, the temperature detection of the power module is usually achieved by using a temperature sensor. However, the sampling value of the temperature sensor cannot truly reflect the actual temperature of the power module, and the temperature difference will vary with factors such as the installation position of the sensor, the assembly process, the switching carrier, and the load operating conditions. The junction temperature value obtained by sampling the temperature sensor is not accurate. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a method, device, equipment, and storage medium for predicting the junction temperature of a power module in an inverter to solve the problem that the existing method cannot accurately predict the operating junction temperature of the power module in the inverter.

[0004] To achieve the above purpose, in the first aspect of the present invention, there is provided a method for predicting the junction temperature of a power module in an inverter, where the inverter is used to drive a motor, and the method includes:

[0005] Obtain the operating parameter information of the inverter and the operating parameter information of the motor;

[0006] Obtain the vector control model of the motor, and determine the switching state information of the power module according to the operating parameter information of the inverter, the operating parameter information of the motor, and the vector control model of the motor;

[0007] Determine the power loss of the power module within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module;

[0008] Obtain the thermal resistance network model of the power module, and predict the junction temperature of the power module in the corresponding unit switching period according to the power loss of the power module within a unit switching period and the thermal resistance network model of the power module.

[0009] Optionally, the power loss of the power module includes the on-state loss and transient loss of the power module; determining the power loss of the power module within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module includes:

[0010] Determining the on-state loss of the power module within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module;

[0011] Determining the transient loss of the power module within a unit switching period according to the operating parameter information of the inverter and the switching state information of the power module.

[0012] Optionally, determining the on-state loss of the power module within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module includes:

[0013] Determining the on-state loss of the power module at each preset moment within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module;

[0014] Taking the average value of the on-state losses of the power module at all preset moments within a unit switching period as the on-state loss of the power module within a unit switching period.

[0015] Optionally, determining the transient loss of the power module within a unit switching period according to the operating parameter information of the inverter and the switching state information of the power module includes:

[0016] Determining the transient loss of the power module at each preset moment within a unit switching period according to the operating parameter information of the inverter and the switching state information of the power module;

[0017] Taking the average value of the transient losses of the power module at all preset moments within a unit switching period as the transient loss of the power module within a unit switching period.

[0018] Optionally, the operating parameter information of the inverter includes the modulation ratio of the inverter and the switching frequency of the power module; the operating parameter information of the motor includes the electrical angular velocity of the motor; the vector control model of the motor is a space vector pulse width modulation model, and the space vector pulse width modulation model is used for vector control of the motor;

[0019] Determining the switching state information of the power module according to the operating parameter information of the inverter, the operating parameter information of the motor, and the vector control model of the motor includes:

[0020] Determine the switching state information of the power module according to the modulation ratio of the inverter, the switching frequency of the power module, the electrical angular velocity of the motor, and the space vector pulse width modulation model;

[0021] The switching state information of the power module includes the switching state of the power module and the action time of the corresponding switching state of the power module within a unit switching period.

[0022] Optionally, the operating parameter information of the inverter further includes the output voltage phase angle of the inverter; the operating parameters of the motor further include the effective value of the phase current of the motor;

[0023] Determine the conduction loss of the power module within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module, including:

[0024] Determine the output phase current of the inverter according to the effective value of the phase current of the motor and the output voltage phase angle of the inverter;

[0025] Determine the conduction current of the power module according to the output phase current of the inverter and the switching state of the power module;

[0026] Determine the conduction voltage of the power module based on the conduction current of the power module, and determine the conduction loss of the power module within a unit switching period according to the conduction voltage and the conduction current of the power module.

[0027] Optionally, the operating parameters of the inverter further include the input bus voltage of the inverter; determine the transient loss of the power module within a unit switching period according to the operating parameter information of the inverter and the switching state information of the power module, including:

[0028] Determine the transient loss of the power module within a unit switching period based on the double pulse test method according to the action time of the corresponding switching state of the power module within a unit switching period and the input bus voltage of the inverter.

[0029] In a second aspect of the present invention, there is provided a device for predicting the junction temperature of a power module in an inverter, which applies the method for predicting the junction temperature of a power module in the inverter as described above. The device includes:

[0030] A data acquisition module, configured to acquire the operating parameter information of the inverter and the operating parameter information of the motor;

[0031] A first calculation module, configured to obtain a vector control model of the motor, and determine switching state information of the power module according to working parameter information of the inverter, working parameter information of the motor, and the vector control model of the motor;

[0032] A second calculation module, configured to determine power loss of the power module within a unit switching period according to the working parameter information of the inverter, the working parameter information of the motor, and the switching state information of the power module;

[0033] A third calculation module, configured to obtain a thermal resistance network model of the power module, and predict the junction temperature of the power module in a corresponding unit switching period according to the power loss of the power module within the unit switching period and the thermal resistance network model of the power module.

[0034] In a third aspect of the present invention, a terminal device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for predicting the junction temperature of the power module in the inverter as described above are implemented.

[0035] In a fourth aspect of the present invention, a computer storage medium is provided. The computer storage medium stores a computer program, and when the computer program is processed and executed, the steps of the method for predicting the junction temperature of the power module in the inverter as described above are implemented.

[0036] Based on the working parameter information of the inverter, the working parameter information of the motor, and the vector control model of the motor, the above technical solution of the present invention determines the switching state information of the power module, and further determines the power loss of the power module within a unit switching period according to the switching state information of the power module, the working parameter information of the inverter, and the working parameter information of the motor. Furthermore, according to the thermal resistance network model of the power module, the junction temperature of the power module in the corresponding switching period is predicted. Compared with the prior art, the prediction of the junction temperature of the power module is not affected by sensors, the prediction result is more accurate, and the dynamic junction temperature of the power module in any switching period within any electrical cycle can be predicted.

[0037] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific embodiment part. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0039] Figure 1It is a flowchart of a method for predicting the junction temperature of a power module in an inverter provided by a preferred embodiment of the present invention;

[0040] Figure 2 It is a schematic diagram of the calculation process of the junction temperature of the power module provided by a preferred embodiment of the present invention;

[0041] Figure 3 It is a schematic diagram of the equivalent circuit of a three-phase voltage source inverter provided by a preferred embodiment of the present invention;

[0042] Figure 4 It is a schematic diagram of the spatial voltage base vector distribution of a three-phase voltage source inverter provided by a preferred embodiment of the present invention;

[0043] Figure 5 It is provided by a preferred embodiment of the present invention for S A Schematic diagram of the example result of the switching state analysis function of the IGBT module in the bridge arm;

[0044] Figure 6 It is provided by a preferred embodiment of the present invention for S A Schematic diagram of the example result of the on-state current analysis function of the IGBT module in the bridge arm;

[0045] Figure 7 Schematic diagram of the output characteristics of the IGBT module provided by a preferred embodiment of the present invention;

[0046] Figure 8 It is provided by a preferred embodiment of the present invention for S A Schematic diagram of the example result of the on-state loss of the IGBT module in the bridge arm;

[0047] Figure 9 It is provided by a preferred embodiment of the present invention for S A Schematic diagram of the example result of the transient switching loss analysis function of the IGBT module in the bridge arm;

[0048] Figure 10 Schematic diagram of the example result of the total loss of the IGBT module in a unit switching cycle provided by a preferred embodiment of the present invention;

[0049] Figure 11 It is provided by a preferred embodiment of the present invention for S A Schematic diagram of the predicted result of the dynamic operating junction temperature of the IGBT module in the bridge arm in a unit electrical cycle;

[0050] Figure 12 It is a schematic block diagram of a device for predicting the junction temperature of a power module in an inverter provided by a preferred embodiment of the present invention.

[0051] Description of reference numerals

[0052] 210 - Data acquisition module, 220 - First calculation module, 230 - Second calculation module, 240 - Third calculation module. Detailed implementation manners

[0053] The following further elaborates on the detailed implementation manners of the present invention with reference to the accompanying drawings. It should be understood that the detailed implementation manners described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0054] As Figure 1 and Figure 2 shown, in the first aspect of this implementation manner, a method for predicting the junction temperature of a power module in an inverter is provided. The inverter is used to drive a motor, and the method includes:

[0055] S100. Obtain the operating parameter information of the inverter and the operating parameter information of the motor;

[0056] S200. Obtain the vector control model of the motor, and determine the switching state information of the power module according to the operating parameter information of the inverter, the operating parameter information of the motor, and the vector control model of the motor;

[0057] S300. Determine the power loss of the power module within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module;

[0058] S400. Obtain the thermal resistance network model of the power module, and predict the junction temperature of the power module in the corresponding unit switching period according to the power loss of the power module within a unit switching period and the thermal resistance network model of the power module.

[0059] In this way, this implementation manner determines the switching state information of the power module based on the operating parameter information of the inverter, the operating parameter information of the motor, and the vector control model of the motor. Furthermore, according to the switching state information of the power module, the operating parameter information of the inverter, and the operating parameter information of the motor, the power loss of the power module within a unit switching period is determined. Then, based on the thermal resistance network model of the power module, the junction temperature of the power module in the corresponding switching period is predicted. Compared with the prior art, the prediction of the junction temperature of the power module is not affected by sensors, the prediction result is more accurate, and the dynamic junction temperature of the power module in any switching period can be predicted.

[0060] Specifically, an electric vehicle achieves vector control of the motor through an inverter, and the power module is an important execution part for the inverter to implement motor control. When the motor parameters of the electric vehicle are determined, accurately predicting the operating junction temperature of the power module is beneficial for engineers to accurately evaluate the performance of the power module, thereby guiding the design of the inverter to ensure the stable operation of the inverter. The IGBT module has both the characteristics of small driving power and fast switching speed of the MOSFET device, and the characteristics of low saturation voltage and large capacity of the bipolar device. Therefore, in this embodiment, the power module in the inverter adopts an IGBT module. Among them, the operating parameter information of the inverter includes the input bus voltage Vdc of the inverter, the modulation ratio M of the inverter, the switching frequency fsw of the IGBT module, and the output voltage phase angle of the inverter The operating parameter information of the motor includes the electrical angular velocity ω of the motor e and the effective value I of the phase current of the motor PHASE_RMS , where the operating parameter information of the inverter and the operating parameter information of the motor can be directly obtained in advance. In this way, when the operating parameter information of the inverter and the operating parameter information of the motor are known, based on the vector control model of the motor, such as the SVPWM model, the switching state information of the IGBT module in any electrical cycle in the steady state of the motor can be determined, where the electrical cycle can be determined according to the motor speed. The switching state information includes whether the switching state of the IGBT module is on or off, and the action time of the IGBT module in any unit switching cycle in any electrical cycle. For example, the on-action time or off-action time of the IGBT module in the unit switching cycle. After obtaining the switching state information of the IGBT module, according to the output voltage phase angle of the inverter the electrical angular velocity ω of the motor e and the effective value IPHASE_RMS of the phase current of the motor, the three-phase output current of the inverter is calculated according to the formula , so as to obtain the conduction current of the IGBT module in the unit switching cycle according to the current switching state of the IGBT module. Moreover, since the IGBT module generally operates in the saturation region, in the saturation region, the output characteristics of the IGBT module are linear. Furthermore, the conduction voltage of the IGBT module is obtained according to the output characteristics of the IGBT module, so that the power loss of the IGBT module in the unit switching cycle can be calculated according to the conduction current and conduction voltage of the IGBT module, and then the junction temperature of the IGBT module in the corresponding unit switching cycle is predicted according to the pre-constructed thermal resistance network model. Among them, the pre-constructed thermal resistance network model can be an IGBT module equivalent thermal resistance model based on the FOSTER network model.

[0061] In this embodiment, the vector control model of the motor is a space vector pulse width modulation model (SVPWM model), where the space vector pulse width modulation model is used to perform vector control on the motor; in step S200, the switching state information of the power module is determined, including:

[0062] Based on the modulation ratio M of the inverter, the switching frequency fsw of the power module, and the electrical angular velocity ω of the motor e and the space vector pulse width modulation model to determine the switching state information of the power module; where the switching state information of the power module includes the switching state of the power module and the action time of the corresponding switching state of the power module within a unit switching period.

[0063] As Figure 3 shown, in this embodiment, a three-phase voltage source inverter is taken as an example to illustrate the SVPWM model, where S A 、S B and S C respectively represent the three upper bridge arms of the three-phase voltage source inverter. Since the working states of the lower bridge arms corresponding to S A 、S B and S C are necessarily opposite to those of the upper bridge arms, therefore, the lower bridge arms are not described in this embodiment. Each bridge arm is an IGBT module, and hereinafter, '0' and '1' are used to represent the off and on states of the IGBT module respectively.

[0064] According to the switching logic of S A 、S B 、S C , 8 space vectors can be combined: the base vectors V 1 、V 2 、V 3 、V 4 、V 5 、V 6 and the zero vectors V 0 、V 7 . As Figure 4 shown, the base vectors V 1 、V 2 、V 3 、V 4 、V 5 、V 6 divide the 360-degree voltage space into 6 sectors. According to the volt-second balance principle, the integral of any space voltage vector within a unit switching period can be equivalently synthesized by two adjacent base vectors in the corresponding sector.

[0065] For example, for the required voltage vector VR Q in sector 1, the corresponding electrical angle is θ(t) = w e*t, according to the principle of vector equivalent synthesis, there is wherein, t 100 and t 110 respectively represent the action time of the base vectors within a unit switching period, and t PWM is the time of a unit switching period.

[0066] In order to reduce the switching times of the IGBT module and reduce the harmonic components of the PWM, the SVPWM model of this embodiment is constructed based on the 7-segment SVPWM modulation method. The specific process of constructing the SVPWM model is as follows:

[0067]

[0068] t PWM = t 100 + t 110 + 2 * t 0 ;

[0069] Further decomposing the above formula gives:

[0070]

[0071]

[0072] Further solving gives:

[0073]

[0074]

[0075]

[0076] wherein, t 0 represents the zero vector.

[0077] And so on. As shown in Table 1, the durations of the corresponding base vectors and zero vectors in the remaining sectors within a unit switching period can be calculated.

[0078]

[0079]

[0080] Table 1

[0081] Based on the SVPWM model, by using relevant mathematical software such as MATLAB, an analytical function model of the switching state of the IGBT module corresponding to the output three-phase current can be constructed, such as: PWM_Pattern TR (t), PWM_Pattern TS (t), PWM_PatternTT (t), where PWM_Pattern TR (t) represents the switching state analysis function of the upper-arm IGBT module corresponding to output A, and PWM_Pattern TS (t) represents the switching state analysis function of the upper-arm IGBT module corresponding to output B, and PWM_Pattern TT (t) represents the switching state analysis function of the upper-arm IGBT module corresponding to output C, and S A The example results of the switching state analysis functions of the IGBT modules of the bridge arms are as Figure 5 shown.

[0082] During the operation of the power module, the power loss of the power module mainly includes the conduction loss and transient loss of the power module; therefore, step S300 includes:[[]]

[0083] S310. Determine the conduction loss of the power module within a unit switching cycle according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module;

[0084] Among them, step S310 includes: according to the effective value I of the phase current of the motor PHASE_RMS and the output voltage phase angle of the inverter to determine the output phase current of the inverter; according to the output phase current of the inverter and the switching state of the power module to determine the conduction current of the power module; based on the conduction current of the power module to determine the conduction voltage of the power module, and according to the conduction voltage and conduction current of the power module to determine the conduction loss of the power module within a unit switching cycle.[[]]

[0085] Establish the output phase current analysis function of the inverter as follows:[[]]

[0086]

[0087]

[0088]

[0089] Among them, i PR (t) represents the A-phase current, and i PS (t) represents the B-phase current, and i PT (t) represents the C-phase current.[[]]

[0090] Define the positive direction of the three-phase current as flowing from the output end to the motor input end. For the high-side three-phase bridge arms S A 、S B 、S C, when the switching state of any bridge arm is logic '1' and the corresponding phase current is positive at the same time, it indicates that the IGBT module in this bridge arm conducts current; otherwise, it indicates that the IGBT module is in the off state or the diode freewheeling state. Then, further establish S A The analytical function of the on-state current of the IGBT module in the bridge arm is:

[0091]

[0092] S A The schematic diagram of the example result of the analytical function of the on-state current of the IGBT module in the bridge arm is as Figure 6 shown.

[0093] Similarly, the analytical function of the on-state current of the IGBT module in the S B bridge arm and the S C bridge arm can be obtained. In this embodiment, only the example of predicting the junction temperature of the IGBT module in the S A bridge arm is used for illustration.

[0094] Since the IGBT module usually operates in the saturation region, as Figure 7 shown, the output characteristics of the IGBT module are linear in the saturation region. Therefore, the analytical function of the on-state voltage and on-state current output characteristics of the IGBT module is:

[0095] V ce (i ce ) = V ce0 + R ce * i ce ;

[0096] Among them, V ce0 represents the threshold voltage of the IGBT module, R ce is the on-resistance of the IGBT module, i ce is the on-state current of the IGBT module. In this embodiment, the on-state current of the IGBT module is the on-state current of the IGBT module. Among them, V ce0 and R ce can be directly obtained according to the IGBT module model.

[0097] Then, construct the analytical function of the on-state loss of the IGBT module in the S A bridge arm as:

[0098] P conducting_loss (t) = i TTR (t) * V ce (i TTR (t));

[0099] S A The example result of the on-state loss of the IGBT module in the bridge arm is as Figure 8 shown.

[0100] S320. Determine the transient loss of the power module within a unit switching period according to the operating parameter information of the inverter and the switching state information of the power module. Specifically, step S320 includes:

[0101] Based on the action time of the switching state corresponding to the power module within a unit switching period and the input bus voltage Vdc of the inverter, determine the transient loss of the power module within a unit switching period based on the double-pulse test method.

[0102] Based on the on-state current analytical function of the IGBT module and the switching loss of the IGBT module calibrated by the double-pulse test method, S can be established A The transient switching loss analytical function of the IGBT module in the bridge arm is:

[0103]

[0104] Among them, E on_calibration represents the turn-on loss of the IGBT module calibrated by the double-pulse test method, i ref represents the reference current of the IGBT module calibrated by the double-pulse test method, E off_calibration represents the turn-off loss of the IGBT module calibrated by the double-pulse test method, Δt represents the turn-on action time or turn-off action time of the IGBT module, represents the current at the moment of transient turn-on of the IGBT module obtained through the on-state current analytical function, represents the current at the moment of transient turn-off of the IGBT module obtained through the on-state current analytical function, t represents the current moment. S A The example results of the transient switching loss analytical function of the IGBT module in the bridge arm are as Figure 9 shown.

[0105] In order to reduce the calculation amount and improve the calculation efficiency, in this embodiment, the unit switching period is divided into n time periods. For example, the unit switching period can be divided into n 1us. Then, step S310 further includes:

[0106] According to the constructed on-state loss analytical function, determine the on-state loss of the power module at each preset moment within a unit switching period, calculate the on-state losses of the IGBT module when t is 1us, t is 2us,..., t is nus respectively, construct an on-state loss averaging analytical function based on the on-state loss analytical function, and use the average value of the on-state losses of the IGBT module at all preset moments within a unit switching period as the on-state loss of the power module within a unit switching period; the on-state loss averaging analytical function is:

[0107]

[0108] Among them, ΔT represents the duration of each time period. In this embodiment, ΔT = 1 us, and t N_PWM represents the Nth switching cycle corresponding to the t moment.

[0109] Similarly, step S320 further includes:

[0110] Determine the transient loss of the IGBT module at each preset moment within a unit switching cycle according to the transient switching loss analysis function; construct an average transient loss analysis function based on the transient switching loss analysis function. Through the transient switching loss analysis function, take the average value of the transient losses of the power module at all preset moments within a unit switching cycle as the transient loss of the power module within a unit switching cycle. The average transient loss analysis function is:

[0111]

[0112] Then, the total loss P total-loss (Δt) of the IGBT module is the sum of the average conduction loss of the IGBT module within a unit switching cycle and the average transient loss of the IGBT module within a unit switching cycle. The total loss P total-loss (Δt) of the IGBT module is as shown in Figure 10 shown.

[0113] Within each unit switching cycle, there are slight differences in the conduction loss and transient loss at each preset moment. In order to reduce the calculation amount and improve the calculation efficiency, use the obtained average value as the conduction loss and transient loss of each unit switching cycle. In this way, when calculating the conduction loss and transient loss of the IGBT module at any unit switching cycle within any unit electrical cycle, it can effectively reduce the calculation amount while ensuring the accuracy of the calculation result, and then accurately calculate the power loss of the IGBT module at any unit switching cycle within any unit electrical cycle.

[0114] In step S400, the thermal resistance network model of this embodiment is obtained by constructing an equivalent thermal resistance model of the IGBT module based on the FOSTER network model. The time-domain function expression of the thermal resistance network model is:

[0115] Then, the junction temperature prediction model of the IGBT module is constructed as:

[0116] ΔT j =(P conducting_loss_IGBT_AVE (t)+P switching_loss_IGBT_AVE (t))*

[0117] Z th_IGBT(t), taking the average value of the on-state loss of the obtained IGBT module and the average value of the transient loss of the IGBT module as inputs, and obtaining the junction temperature of the IGBT module through the junction temperature prediction model of the IGBT module, with S A Taking the IGBT module of the bridge arm as an example, the predicted result of its dynamic operating junction temperature within a unit electrical cycle is as Figure 11 shown.

[0118] As Figure 12 shown, in the second aspect of the present invention, there is provided a device for predicting the junction temperature of a power module in an inverter, applying the above-mentioned method for predicting the junction temperature of a power module in an inverter. The device includes:

[0119] A data acquisition module, configured to acquire the operating parameter information of the inverter and the operating parameter information of the motor;

[0120] A first calculation module, configured to obtain the vector control model of the motor, and determine the switching state information of the power module according to the operating parameter information of the inverter, the operating parameter information of the motor, and the vector control model of the motor;

[0121] A second calculation module, configured to determine the power loss of the power module within a unit switching cycle according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module;

[0122] A third calculation module, configured to obtain the thermal resistance network model of the power module, and predict the junction temperature of the power module corresponding to the unit switching cycle according to the power loss of the power module within the unit switching cycle and the thermal resistance network model of the power module.

[0123] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the above-mentioned division of each functional module is used as an example for illustration. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working process of the modules in the above device can refer to the corresponding process in the foregoing method embodiments and will not be repeated here.

[0124] In a third aspect of the present invention, there is provided a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the power module junction temperature prediction method in the above-mentioned inverter are implemented.

[0125] In a fourth aspect of the present invention, there is provided a computer storage medium storing a computer program, and when the computer program is processed and executed, the steps of the power module junction temperature prediction method in the above-mentioned inverter are implemented.

[0126] In summary, based on the obtained working parameter information of the inverter and the working parameter information of the motor, this embodiment can effectively predict the dynamic junction temperature of the IGBT module in any switching cycle within any electrical cycle during the steady operation of the motor through the constructed switching state analysis function, on-state current analysis function, on-state loss analysis function, transient loss analysis function, and thermal resistance network model of the power module. Compared with the prior art, the prediction result is more accurate and has a wider application range, thus being beneficial to guiding the design of the inverter and shortening the design process of the inverter.

[0127] The optional embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept scope of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0128] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without conflict. To avoid unnecessary repetition, the embodiments of the present invention do not separately describe various possible combination methods.

[0129] In addition, any combination can be made among various different embodiments of the present invention as long as it does not violate the idea of the embodiments of the present invention, and it should also be regarded as the content disclosed by the embodiments of the present invention.

Claims

1. A method for predicting the junction temperature of a power module in an inverter, where the inverter is used to drive a motor, Characterized in that, The method includes: Obtain the working parameter information of the inverter and the working parameter information of the motor; Obtain the vector control model of the motor, and determine the switching state information of the power module according to the working parameter information of the inverter, the working parameter information of the motor, and the vector control model of the motor; Determine the power loss of the power module in a unit switching period according to the working parameter information of the inverter, the working parameter information of the motor, and the switching state information of the power module; Obtain the thermal resistance network model of the power module, and predict the junction temperature of the power module in the corresponding unit switching period according to the power loss of the power module in a unit switching period and the thermal resistance network model of the power module.

2. The method for predicting the junction temperature of a power module in an inverter according to claim 1, Characterized in that, The power loss of the power module includes the on-state loss and the transient loss of the power module; determining the power loss of the power module in a unit switching period according to the working parameter information of the inverter, the working parameter information of the motor, and the switching state information of the power module includes: Determine the on-state loss of the power module in a unit switching period according to the working parameter information of the inverter, the working parameter information of the motor, and the switching state information of the power module; Determine the transient loss of the power module in a unit switching period according to the working parameter information of the inverter and the switching state information of the power module.

3. The method for predicting the junction temperature of a power module in an inverter according to claim 2, Characterized in that, Determining the on-state loss of the power module in a unit switching period according to the working parameter information of the inverter, the working parameter information of the motor, and the switching state information of the power module includes: Determine the on-state loss of the power module at each preset moment in a unit switching period according to the working parameter information of the inverter, the working parameter information of the motor, and the switching state information of the power module; Take the average value of the on-state losses of the power module at all preset moments in a unit switching period as the on-state loss of the power module in a unit switching period.

4. The method for predicting the junction temperature of a power module in an inverter according to claim 2, Characterized in that, Determining the transient loss of the power module in a unit switching period according to the working parameter information of the inverter and the switching state information of the power module includes: Determine the transient loss of the power module at each preset moment in a unit switching period according to the working parameter information of the inverter and the switching state information of the power module; Take the average value of the transient losses of the power module at all preset moments in a unit switching period as the transient loss of the power module in a unit switching period.

5. The method for predicting the junction temperature of a power module in an inverter according to claim 2, Characterized in that, The operating parameter information of the inverter includes the modulation ratio of the inverter and the switching frequency of the power module; the operating parameter information of the motor includes the electrical angular velocity of the motor; the vector control model of the motor is a space vector pulse width modulation model, and the space vector pulse width modulation model is used to perform vector control on the motor; Determining the switching state information of the power module according to the operating parameter information of the inverter, the operating parameter information of the motor, and the vector control model of the motor, includes: Determining the switching state information of the power module according to the modulation ratio of the inverter, the switching frequency of the power module, the electrical angular velocity of the motor, and the space vector pulse width modulation model; The switching state information of the power module includes the switching state of the power module and the action time of the corresponding switching state of the power module within a unit switching period.

6. The method for predicting the junction temperature of a power module in an inverter according to claim 5, wherein, The operating parameter information of the inverter further includes the output voltage phase angle of the inverter; the operating parameter information of the motor further includes the effective value of the phase current of the motor; Determining the conduction loss of the power module within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module, includes: Determining the output phase current of the inverter according to the effective value of the phase current of the motor and the output voltage phase angle of the inverter; Determining the conduction current of the power module according to the output phase current of the inverter and the switching state of the power module; Determining the conduction voltage of the power module based on the conduction current of the power module, and determining the conduction loss of the power module within a unit switching period according to the conduction voltage and the conduction current of the power module.

7. The method for predicting the junction temperature of a power module in an inverter according to claim 5, wherein, The operating parameters of the inverter further include the input bus voltage of the inverter; Determining the transient loss of the power module within a unit switching period according to the operating parameter information of the inverter and the switching state information of the power module, includes: Determining the transient loss of the power module within a unit switching period based on the double pulse test method according to the action time of the corresponding switching state of the power module within a unit switching period and the input bus voltage of the inverter.

8. An apparatus for predicting the junction temperature of a power module in an inverter, applying the method for predicting the junction temperature of a power module in an inverter according to any one of claims 1-7, wherein, The apparatus includes: A data acquisition module, configured to acquire the operating parameter information of the inverter and the operating parameter information of the motor; A first calculation module, configured to acquire the vector control model of the motor, and determine the switching state information of the power module according to the operating parameter information of the inverter, the operating parameter information of the motor, and the vector control model of the motor; A second calculation module, configured to determine the power loss of the power module within a unit switching period according to the operating parameter information of the inverter, the operating parameter information of the motor, and the switching state information of the power module; A third calculation module, configured to obtain the thermal resistance network model of the power module, and predict the junction temperature of the power module corresponding to the unit switching period according to the power loss of the power module within the unit switching period and the thermal resistance network model of the power module.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein, when the processor executes the computer program, the steps of the method for predicting the junction temperature of the power module in the inverter according to any one of claims 1 to 7 are implemented.

10. A computer storage medium storing a computer program, wherein, when the computer program is executed, the steps of the method for predicting the junction temperature of the power module in the inverter according to any one of claims 1 to 7 are implemented.

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