IGBT overcurrent protection method and device, motor control system and vehicle

Abstract

The invention relates to the technical field of vehicles, in particular to an IGBT overcurrent protection method and device, a motor control system and a vehicle, and the method comprises the steps: obtaining an inverter, and a first state parameter and a second state parameter of an IGBT in the inverter in a current operation state; calculating a reduction factor of the IGBT based on the first state parameter and / or the second state parameter, and calculating an overcurrent threshold value of the IGBT based on the reduction factor; and generating a PWM signal based on the overcurrent threshold, and controlling the IGBT based on the PWM signal to realize overcurrent protection of the IGBT. Therefore, the problems of poor IGBT overcurrent protection flexibility, incapability of dynamic adjustment and the like in the prior art are solved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to an IGBT overcurrent protection method, device, motor control system and vehicle. Background Art

[0002] IGBT (Insulated Gate Bipolar Transistor) is a commonly used power electronic device, widely used in inverters, motor drives and other fields. Due to its high voltage and high current characteristics, IGBT may encounter various abnormal situations during operation, among which overcurrent is an important problem. Overcurrent protection is crucial to ensure the safe operation of IGBT.

[0003] At present, related technologies mostly use fixed values ​​for setting the hardware overcurrent threshold, which is not convenient for dynamically adjusting the overcurrent protection of the IGBT according to actual usage and has poor flexibility. Summary of the invention

[0004] The present application provides an IGBT overcurrent protection method, device, motor control system and vehicle to solve the problem that the IGBT overcurrent protection in the prior art has poor flexibility and cannot be dynamically adjusted.

[0005] The first aspect of the present application provides an IGBT overcurrent protection method, comprising the following steps: obtaining a first state parameter and a second state parameter of an inverter and an IGBT in the inverter under a current operating state; calculating a reduction factor of the IGBT based on the first state parameter and / or the second state parameter, and calculating an overcurrent threshold of the IGBT based on the reduction factor; generating a PWM signal based on the overcurrent threshold, and controlling the IGBT based on the PWM signal to achieve overcurrent protection for the IGBT.

[0006] Optionally, in one embodiment of the present application, the reduction factor includes first to third reduction factors, the first state parameter includes limiting power and bus voltage, and the second state parameter includes junction temperature.

[0007] Optionally, in one embodiment of the present application, calculating the reduction factor of the IGBT based on the first state parameter and / or the second state parameter also includes: querying a first corresponding relationship based on the current junction temperature to determine a first allowable maximum current, the first corresponding relationship stores the correspondence between the junction temperature and the first allowable maximum current; querying a second corresponding relationship based on the current limiting power to determine the second allowable maximum current, wherein the second corresponding relationship stores the correspondence between the limiting power and the second allowable maximum current; querying a third corresponding relationship based on the current bus voltage to determine the third allowable maximum current, wherein the third corresponding relationship stores the correspondence between the bus voltage and the third allowable maximum current; and calculating the first to third reduction factors based on the first allowable maximum current, the second allowable maximum current and the third allowable maximum current, respectively.

[0008] Optionally, in one embodiment of the present application, the calculation formula of the first reduction factor is:

[0009]

[0010] Among them, a1 is the first reduction factor, I max is the maximum current allowed by the inverter, I limit1 is the first maximum allowable current;

[0011] The calculation formula of the second reduction factor is:

[0012]

[0013] Among them, a2 is the second reduction factor, I max is the maximum current allowed by the inverter, U is the bus voltage, P limit To limit power;

[0014] The calculation formula of the third reduction factor is:

[0015]

[0016] Among them, a3 and the third reduction factor, I max is the maximum current allowed by the inverter, I limit3 The third maximum allowed current.

[0017] Optionally, in one embodiment of the present application, calculating the overcurrent threshold of the IGBT based on the reduction factor includes: selecting the maximum value of the first to third reduction factors; and calculating the overcurrent threshold based on the maximum value and the maximum current allowed by the inverter.

[0018] Optionally, in one embodiment of the present application, generating a PWM signal based on an overcurrent threshold includes: calculating an overcurrent voltage reference value based on the overcurrent threshold; and generating a PWM signal based on the overcurrent voltage reference value.

[0019] The second aspect of the present application provides an IGBT overcurrent protection device, including: an acquisition module, used to obtain a first state parameter and a second state parameter of an inverter and an IGBT in the inverter under a current operating state; a calculation module, used to calculate a reduction factor of the IGBT based on the first state parameter and / or the second state parameter, and calculate an overcurrent threshold of the IGBT based on the reduction factor; a control module, used to generate a PWM signal based on the overcurrent threshold, and control the IGBT based on the PWM signal to achieve overcurrent protection for the IGBT.

[0020] Optionally, in one embodiment of the present application, the reduction factor includes first to third reduction factors, the first state parameter includes limiting power and bus voltage, and the second state parameter includes junction temperature.

[0021] Optionally, in one embodiment of the present application, the calculation module is further used to: determine a first allowable maximum current by querying a first corresponding relationship based on the current junction temperature, the first corresponding relationship storing the corresponding relationship between the junction temperature and the first allowable maximum current; determine a second allowable maximum current by querying a second corresponding relationship based on the current limiting power, wherein the second corresponding relationship stores the corresponding relationship between the limiting power and the second allowable maximum current; determine a third allowable maximum current by querying a third corresponding relationship based on the current bus voltage, wherein the third corresponding relationship stores the corresponding relationship between the bus voltage and the third allowable maximum current; and respectively calculate the first to third reduction factors based on the first allowable maximum current, the second allowable maximum current and the third allowable maximum current.

[0022] Optionally, in one embodiment of the present application, the calculation formula of the first reduction factor is:

[0023]

[0024] Among them, a1 is the first reduction factor, I max is the maximum current allowed by the inverter, I limit1 is the first maximum allowable current;

[0025] The calculation formula of the second reduction factor is:

[0026]

[0027] Among them, a2 is the second reduction factor, I max is the maximum current allowed by the inverter, U is the bus voltage, P limit To limit power;

[0028] The calculation formula of the third reduction factor is:

[0029]

[0030] Among them, a3 and the third reduction factor, I max is the maximum current allowed by the inverter, I limit3 The third maximum allowed current.

[0031] Optionally, in one embodiment of the present application, the calculation module is further used to: select a maximum value among the first to third reduction factors; and calculate an overcurrent threshold based on the maximum value and a maximum current allowed by the inverter.

[0032] Optionally, in one embodiment of the present application, the control module is further used to: generate a PWM signal based on an overcurrent threshold, including: calculating an overcurrent voltage reference value based on the overcurrent threshold; and generating a PWM signal based on the overcurrent voltage reference value.

[0033] The third aspect of the present application provides a motor control system, including: a control unit, used to execute the IGBT overcurrent protection method as described in the above embodiment to adjust the overcurrent threshold of the IGBT; a data acquisition unit connected to the control unit, used to collect first state parameters and second state parameters of the inverter and the IGBT in the inverter under the current operating state, and transmit the first state parameters and the second state parameters to the control unit.

[0034] A fourth aspect of the present application provides a vehicle, comprising a motor control system according to the above embodiment.

[0035] The fifth aspect of the present application provides a computer-readable storage medium on which a computer program or instruction is stored. The computer program or instruction is executed by a processor to implement the IGBT overcurrent protection method as described in the above embodiment.

[0036] Therefore, this application has at least the following beneficial effects:

[0037] The embodiment of the present application can calculate the reduction factor of the IGBT according to the operating parameters of the inverter and the IGBT in the current operating state, and calculate the overcurrent threshold according to the reduction factor, generate a PWM signal according to the overcurrent threshold, and then control the IGBT based on the PWM signal to dynamically adjust the overcurrent threshold based on the current situation, with high flexibility, ensuring that the IGBT can be effectively protected under various working conditions, and better protecting the IGBT. Therefore, the technical problems of poor flexibility and inability to dynamically adjust the IGBT overcurrent protection in the prior art are solved.

[0038] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0040] Figure 1 A flow chart of an IGBT overcurrent protection method provided according to an embodiment of the present application;

[0041] Figure 2 A schematic diagram of a reduction factor decision according to an embodiment of the present application;

[0042] Figure 3 A complete flow chart of an IGBT overcurrent protection method provided according to an embodiment of the present application;

[0043] Figure 4 A double pulse experiment diagram provided according to an embodiment of the present application;

[0044] Figure 5 This is an example diagram of an IGBT overcurrent protection device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0046] The following describes the IGBT overcurrent protection method, device, motor control system and vehicle of the embodiment of the present application with reference to the accompanying drawings. In view of the problem that the current related technologies mentioned in the above background technology mostly use fixed values ​​for the setting of the hardware overcurrent threshold, which is not convenient for the IGBT overcurrent protection to be dynamically adjusted according to the actual usage, and has poor flexibility, the present application provides an IGBT overcurrent protection method, in which the reduction factor of the IGBT can be calculated according to the operating parameters of the inverter and the IGBT in the current operating state, and the overcurrent threshold is calculated according to the reduction factor, and a PWM signal is generated according to the overcurrent threshold, and then the IGBT is controlled based on the PWM signal to achieve dynamic adjustment of the overcurrent threshold based on the current situation, so as to ensure that the IGBT can be effectively protected under various working conditions, and better protect the IGBT. As a result, the problems of poor flexibility and inability to dynamically adjust the IGBT overcurrent protection in the prior art are solved.

[0047] Specifically, Figure 1 A schematic flow chart of an IGBT overcurrent protection method provided in an embodiment of the present application.

[0048] like Figure 1 As shown, the IGBT overcurrent protection method includes the following steps:

[0049] In step S101, a first state parameter and a second state parameter of an inverter and an IGBT in the inverter in a current operating state are obtained.

[0050] Among them, IGBT (insulated gate bipolar transistor) is a commonly used power electronic device, widely used in frequency converters, motor drives and other fields; the first state parameter includes the inverter's limiting power and bus voltage, and the second state parameter includes the IGBT's junction temperature.

[0051] It is understandable that the implementation of the present application can obtain the first state parameters and the second state parameters of the inverter and the IGBT in the inverter under the current operating state, such as the state parameters under different junction temperatures, so as to subsequently perform overcurrent protection on the IGBT.

[0052] In step S102 , a reduction factor of the IGBT is calculated based on the first state parameter and / or the second state parameter, and an overcurrent threshold of the IGBT is calculated based on the reduction factor.

[0053] The reduction factors include first to third reduction factors.

[0054] It can be understood that the embodiment of the present application can calculate the reduction consistency of the IGBT based on the first state parameter and the second state parameter, and calculate the overcurrent threshold of the IGBT based on the reduction factor.

[0055] In an embodiment of the present application, the reduction factor of the IGBT is calculated based on the first state parameter and / or the second state parameter, and also includes: querying a first corresponding relationship based on the current junction temperature to determine the first allowable maximum current, the first corresponding relationship stores the correspondence between the junction temperature and the first allowable maximum current; querying a second corresponding relationship based on the current limiting power to determine the second allowable maximum current, wherein the second corresponding relationship stores the correspondence between the limiting power and the second allowable maximum current; querying a third corresponding relationship based on the current bus voltage to determine the third allowable maximum current, wherein the third corresponding relationship stores the correspondence between the bus voltage and the third allowable maximum current; and calculating the first to third reduction factors based on the first allowable maximum current, the second allowable maximum current and the third allowable maximum current, respectively.

[0056] It can be understood that the embodiments of the present application can pre-construct a correspondence relationship to determine the maximum allowable current, the first correspondence relationship stores the correspondence between the junction temperature and the first maximum allowable current, the second correspondence relationship stores the correspondence between the limited power and the second maximum allowable current, and the third correspondence relationship stores the correspondence between the bus voltage and the third maximum allowable current, that is, the correspondence relationship is queried according to the first state parameter and the second state parameter in the current operating state to determine the maximum allowable current.

[0057] Specifically, a first corresponding relationship is queried according to the current junction temperature to determine the first maximum allowable current; a second corresponding relationship is queried according to the current limited power to determine the second maximum allowable current; and a third corresponding relationship is queried according to the current bus voltage to determine the third maximum allowable current.

[0058] In the embodiment of the present application, the calculation formula of the first reduction factor is:

[0059]

[0060] Among them, a1 is the first reduction factor, I max is the maximum current allowed by the inverter, I limit1 is the first maximum allowable current;

[0061] The calculation formula of the second reduction factor is:

[0062]

[0063] Among them, a2 is the second reduction factor, I max is the maximum current allowed by the inverter, U is the bus voltage, P limit To limit power;

[0064] The calculation formula of the third reduction factor is:

[0065]

[0066] Among them, a3 and the third reduction factor, I max is the maximum current allowed by the inverter, I limit3 The third maximum allowed current.

[0067] It should be noted that the principles for setting the first to third reduction factors are as follows.

[0068] The reduction factor a1 is set based on the estimated junction temperature of the IGBT. The heat dissipation capacity of the controller determines the difference in the maximum current at different junction temperatures. Real-time monitoring of the junction temperature and timely hardware overcurrent protection can not only bring out the maximum capacity of the controller, but also ensure that the controller will not be damaged by overheating, and the safety of the whole vehicle is higher. This factor changes from 0 to 1 at the high stage of the junction temperature, and the calculation formula is as follows:

[0069]

[0070] Among them, I limit1 is the maximum current allowed at different junction temperatures, I max It is the maximum current value allowed by the inverter.

[0071] Set the reduction factor a2 according to the inverter power limit. The inverter power limit changes with the fault level, speed, battery properties, etc., so the inverter hardware overcurrent threshold also changes. The reduction factor a2 is calculated as follows:

[0072]

[0073] Where U is the bus voltage, P limit is the limited power.

[0074] The reduction factor a3 is set according to the bus voltage. Due to the existence of stray inductance distributed inside the line and device, the IGBT collector current drops rapidly to zero during the shutdown transient. The reverse recovery diode connected in parallel will generate a higher switching surge voltage during reverse recovery, which is superimposed on the bus voltage. If the voltage spike is too large and exceeds the breakdown voltage Uces, overvoltage breakdown will occur. The voltage spike is related to the current drop rate di / dt, so the bus voltage affects the current maximum value threshold. Different overcurrent thresholds are set according to the bus voltage. The reduction factor a3 is calculated as follows:

[0075]

[0076] Among them, I limit3 It is a data set of maximum allowable current obtained through double pulse test calibration under different bus voltages.

[0077] In an embodiment of the present application, the overcurrent threshold of the IGBT is calculated based on the reduction factor, including: selecting the maximum value of the first to third reduction factors; and calculating the overcurrent threshold based on the maximum value and the maximum current allowed by the inverter.

[0078] It is understandable that the embodiment of the present application can select the maximum value of the reduction factor, and the reduction factor decision is as follows: Figure 2 As shown, Figure 2 The junction temperature current threshold reduction factor in is equivalent to the first reduction factor, the power current threshold reduction factor is the second reduction factor, and the bus voltage current threshold reduction factor is the third reduction factor. The overcurrent threshold is calculated based on the maximum value and the maximum current allowed by the inverter. The specific calculation formula is:

[0079] I th =(1-max(a1,a2,a3))*I max ;

[0080] Among them, I th is the overcurrent threshold.

[0081] In step S103, a PWM signal is generated based on the overcurrent threshold, and the IGBT is controlled based on the PWM signal to achieve overcurrent protection for the IGBT.

[0082] It can be understood that the embodiments of the present application can generate a PWM signal based on an overcurrent threshold, and control the IGBT based on the PWM signal to achieve overcurrent protection for the IGBT.

[0083] In an embodiment of the present application, generating a PWM signal based on an overcurrent threshold includes: calculating an overcurrent voltage reference value based on the overcurrent threshold; and generating a PWM signal based on the overcurrent voltage reference value.

[0084] It can be understood that the embodiments of the present application can calculate the overcurrent voltage reference value based on the overcurrent threshold, and generate a PWM signal based on the overcurrent voltage reference value, that is, convert the overcurrent threshold into a corresponding voltage value, and use the PWM duty cycle output and filtering method to generate the reference analog voltage required for the overcurrent comparison of the hardware circuit.

[0085] The overcurrent voltage reference value required for the specific calculation of the hardware circuit is:

[0086] U thUp =b*I th ;

[0087] U thDown =b1*I th ;

[0088] Among them, U thUp The maximum positive current (I th ) corresponding voltage threshold; U thDown The maximum negative current (-I th ) corresponds to the voltage threshold. b and b1 are scaling coefficients obtained from the hardware circuit parameters.

[0089] The IGBT overcurrent protection method of the present application is described below by a specific embodiment. Figure 3 As shown, including:

[0090] Step 1: Calculate the current reduction factor a1 for junction temperature. The power loss generated by the IGBT during operation causes the junction temperature of the device to rise and fluctuate, resulting in uneven temperature distribution of the internal chip. For example, the maximum operating junction temperature of the Infineon IGBT module in the switching state is generally 150 degrees. In the case of short-term overload, the maximum operating junction temperature of the IGBT can reach 175 degrees. When the junction temperature is closer to the maximum value, the less room is left for power margin. Under the premise of effectively protecting the IGBT, the maximum current for high junction temperature will be limited to ensure timely operation of the protection circuit. Considering the error of junction temperature estimation and the action time of the protection circuit, according to the RC thermal network model, as well as the conduction and switching losses, the maximum protection current for the junction temperature can be experimentally estimated and a table can be formed. As the junction temperature increases, the maximum protection current decreases.

[0091] Ilimit1 =f(T j );

[0092]

[0093] Step 2: Calculate the current reduction factor a2 for power limitation. Since the inverter control program takes into account the protection of the inverter and other devices, such as motors and batteries, various abnormal operating conditions will occur, such as stalling, stator overtemperature, overspeed, etc. The protection measures taken generally include power reduction methods. Based on the power reduction, in order to better and more timely protect components, the overcurrent threshold should be dynamically modulated. The current formula for calculating the overcurrent is as follows:

[0094]

[0095] Where U is the bus voltage, P limit is the limited power.

[0096] The current reduction factor for power limiting is calculated as follows:

[0097]

[0098] Step 3: Calculate the current reduction factor a3 with respect to the bus voltage. During the turn-off transient, the IGBT collector current drops rapidly to zero, resulting in a spike voltage between the collector and emitter of an IGBT due to stray inductance, such as Figure 4 As shown in the figure. When the bus voltage remains unchanged, the peak value increases as the collector current increases. Through the double pulse experiment, the maximum allowable current data set under different bus voltages can be measured to ensure that the IGBT will not have voltage breakdown.

[0099] Calculation method of reduction factor a3:

[0100]

[0101] Among them, i limit3 It is the maximum allowable current data set obtained through double pulse test calibration under different bus voltages; I max It is the maximum current value allowed by the inverter.

[0102] Step 4: Calculate the final overcurrent threshold and the overcurrent voltage reference value required by the corresponding hardware circuit. Take the largest of the three reduction factors as the final reduction factor to calculate the current to be reduced and obtain the overcurrent threshold. The calculation method is as follows:

[0103] I th =(1-max(a1,a2,a3))*I max ;

[0104] Calculate the overcurrent voltage reference value required by the hardware circuit:

[0105] U thUp =b*I th ;

[0106] U thDown =b1*I th ;

[0107] Among them: U thUp The maximum positive current (I th ) corresponding voltage threshold; U thDown The maximum negative current (-I th ) corresponds to the voltage threshold. b and b1 are scaling coefficients obtained from the hardware circuit parameters.

[0108] Step 5: According to the overcurrent voltage reference value required by the hardware circuit, use the timing module of the chip to set two PWMs and output voltage using the duty cycle method. The duty cycle is calculated as follows:

[0109]

[0110] Among them, U ref The reference voltage for the chip is 5V.

[0111] According to the IGBT overcurrent protection method proposed in the embodiment of the present application, the reduction factor of the IGBT can be calculated according to the operating parameters of the inverter and the IGBT in the current operating state, and the overcurrent threshold can be calculated according to the reduction factor. A PWM signal is generated according to the overcurrent threshold, and then the IGBT is controlled based on the PWM signal to achieve dynamic adjustment of the overcurrent threshold based on the current situation. It has high flexibility and ensures that the IGBT can be effectively protected under various working conditions, thereby better protecting the IGBT.

[0112] Next, the IGBT overcurrent protection device proposed according to the embodiment of the present application is described with reference to the accompanying drawings.

[0113] Figure 5 It is a block diagram of an IGBT overcurrent protection device according to an embodiment of the present application.

[0114] like Figure 5 As shown, the IGBT overcurrent protection device 10 includes: an acquisition module 100 , a calculation module 200 and a control module 300 .

[0115] Among them, the acquisition module 100 is used to obtain the first state parameter and the second state parameter of the inverter and the IGBT in the inverter under the current operating state; the calculation module 200 is used to calculate the reduction factor of the IGBT based on the first state parameter and / or the second state parameter, and calculate the overcurrent threshold of the IGBT based on the reduction factor; the control module 300 is used to generate a PWM signal based on the overcurrent threshold, and control the IGBT based on the PWM signal to achieve overcurrent protection for the IGBT.

[0116] In the embodiment of the present application, the reduction factor includes first to third reduction factors, the first state parameter includes limited power and bus voltage, and the second state parameter includes junction temperature.

[0117] In an embodiment of the present application, the calculation module 20 is further used to: query a first corresponding relationship based on the current junction temperature to determine a first allowable maximum current, the first corresponding relationship stores the corresponding relationship between the junction temperature and the first allowable maximum current; query a second corresponding relationship based on the current limiting power to determine the second allowable maximum current, wherein the second corresponding relationship stores the corresponding relationship between the limiting power and the second allowable maximum current; query a third corresponding relationship based on the current bus voltage to determine the third allowable maximum current, wherein the third corresponding relationship stores the corresponding relationship between the bus voltage and the third allowable maximum current; and calculate the first to third reduction factors based on the first allowable maximum current, the second allowable maximum current and the third allowable maximum current, respectively.

[0118] In the embodiment of the present application, the calculation formula of the first reduction factor is:

[0119]

[0120] Among them, a1 is the first reduction factor, I max is the maximum current allowed by the inverter, I limit1 is the first maximum allowable current;

[0121] The calculation formula of the second reduction factor is:

[0122]

[0123] Among them, a2 is the second reduction factor, I max is the maximum current allowed by the inverter, U is the bus voltage, P limit To limit power;

[0124] The calculation formula of the third reduction factor is:

[0125]

[0126] Among them, a3 and the third reduction factor, I maxis the maximum current allowed by the inverter, I limit3 The third maximum allowed current.

[0127] In the embodiment of the present application, the calculation module 200 is further used to: select the maximum value among the first to third reduction factors; and calculate the overcurrent threshold based on the maximum value and the maximum current allowed by the inverter.

[0128] In the embodiment of the present application, the control module 300 is further used to: generate a PWM signal based on an overcurrent threshold, including: calculating an overcurrent voltage reference value based on the overcurrent threshold; and generating a PWM signal based on the overcurrent voltage reference value.

[0129] It should be noted that the aforementioned explanation of the IGBT overcurrent protection method embodiment is also applicable to the IGBT overcurrent protection device of this embodiment, and will not be repeated here.

[0130] According to the IGBT overcurrent protection device proposed in the embodiment of the present application, the reduction factor of the IGBT can be calculated according to the operating parameters of the inverter and the IGBT in the current operating state, and the overcurrent threshold can be calculated according to the reduction factor. A PWM signal is generated according to the overcurrent threshold, and then the IGBT is controlled based on the PWM signal to achieve dynamic adjustment of the overcurrent threshold based on the current situation. It has high flexibility and ensures that the IGBT can be effectively protected under various working conditions, thereby better protecting the IGBT.

[0131] An embodiment of the present application also provides a motor control system, including: a control unit and a data acquisition unit.

[0132] Among them, the control unit is used to execute the above-mentioned IGBT overcurrent protection method to adjust the overcurrent threshold of the IGBT; the data acquisition unit connected to the control unit is used to collect the first state parameters and the second state parameters of the inverter and the IGBT in the inverter under the current operating state, and transmit the first state parameters and the second state parameters to the control unit.

[0133] It can be understood that the data acquisition unit in the motor control system of the embodiment of the present application is used to collect parameters, and the control unit is used to execute the above IGBT overcurrent protection method to achieve protection of the IGBT.

[0134] An embodiment of the present application also provides a vehicle, comprising the motor control system as described above.

[0135] An embodiment of the present application also provides a computer-readable storage medium on which a computer program or instruction is stored. When the computer program or instruction is executed by a processor, the above-mentioned IGBT overcurrent protection method is implemented.

[0136] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0137] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0138] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0139] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one or a combination of multiple of the following technologies known in the art: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0140] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

Claims

1. An IGBT overcurrent protection method, characterized in that: The following steps are involved: Acquire a first state parameter and a second state parameter of an inverter and an IGBT in the inverter in a current operating state; Calculating a reduction factor of the IGBT based on the first state parameter and / or the second state parameter, and calculating an overcurrent threshold of the IGBT based on the reduction factor; A PWM signal is generated based on the over-current threshold, and the IGBT is controlled based on the PWM signal to achieve over-current protection for the IGBT.

2. The IGBT overcurrent protection method according to claim 1, characterized in that: The reduction factors include first to third reduction factors, the first state parameter includes limited power and bus voltage, and the second state parameter includes junction temperature.

3. The IGBT overcurrent protection method according to claim 2, characterized in that: The calculating of the reduction factor of the IGBT based on the first state parameter and / or the second state parameter further includes: querying a first corresponding relationship based on the current junction temperature to determine a first maximum allowable current, wherein the first corresponding relationship stores a corresponding relationship between the junction temperature and the first maximum allowable current; Based on the current limited power, query a second corresponding relationship to determine a second maximum allowable current, wherein the second corresponding relationship stores a corresponding relationship between the limited power and the second maximum allowable current; Based on the current bus voltage, query a third corresponding relationship to determine a third maximum allowable current, wherein the third corresponding relationship stores a corresponding relationship between the bus voltage and the third maximum allowable current; The first to third clipping factors are calculated based on the first allowed maximum current, the second allowed maximum current, and the third allowed maximum current, respectively.

4. The IGBT overcurrent protection method according to claim 3, characterized in that: The calculation formula of the first reduction factor is: Among them, a1 is the first reduction factor, I max is the maximum current allowed by the inverter, I limit1 is the first maximum allowable current; The calculation formula of the second reduction factor is: Among them, a2 is the second reduction factor, I max is the maximum current allowed by the inverter, U is the bus voltage, P limit To limit power; The calculation formula of the third reduction factor is: Among them, a3 and the third reduction factor, I max is the maximum current allowed by the inverter, I limit3 The third maximum allowed current.

5. The IGBT overcurrent protection method according to claim 2, characterized in that: The calculating the overcurrent threshold of the IGBT based on the reduction factor comprises: Selecting the maximum value among the first to third reduction factors; The overcurrent threshold is calculated based on the maximum value and a maximum current allowed by the inverter.

6. The IGBT overcurrent protection method according to claim 1, characterized in that: The generating a PWM signal based on the over-current threshold comprises: Calculating an overcurrent voltage reference value based on the overcurrent threshold; The PWM signal is generated based on the overcurrent voltage reference value.

7. An IGBT overcurrent protection device, characterized in that: include: An acquisition module, used for acquiring a first state parameter and a second state parameter of an inverter and an IGBT in the inverter in a current operating state; a calculation module, configured to calculate a reduction factor of the IGBT based on the first state parameter and / or the second state parameter, and calculate an overcurrent threshold of the IGBT based on the reduction factor; A control module is used to generate a PWM signal based on the over-current threshold, and control the IGBT based on the PWM signal to achieve over-current protection for the IGBT.

8. A motor control system, characterized in that: include: A control unit, configured to execute the IGBT overcurrent protection method according to any one of claims 1 to 6, so as to adjust the overcurrent threshold of the IGBT; The data acquisition unit connected to the control unit is used to collect the first state parameter and the second state parameter of the inverter and the IGBT in the inverter under the current operating state, and transmit the first state parameter and the second state parameter to the control unit.

9. A vehicle, characterized in that: Comprising the motor control system as claimed in claim 8.

10. A computer-readable storage medium having a computer program or instruction stored thereon, characterized in that: The computer program or instruction is executed by a processor to implement the IGBT overcurrent protection method according to any one of claims 1 to 6.

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