A method, apparatus, device, and storage medium for stall protection of an electric drive system.

Abstract

This invention discloses a stall protection method, device, equipment, and storage medium for an electric drive system. The scheme may include: acquiring the initial temperature of the IGBT module in the motor controller and the starting torque of the motor when the motor enters the starting state; defining a number of time nodes sequentially, with the moment when the motor enters the starting state as the zero point; for the number of time nodes, provided that the empirical temperature rise value of the IGBT module is less than the temperature rise margin, if it is detected that there is no time node in the number of time nodes where the actual speed of the motor exceeds the speed threshold of the motor in the running state, then if the torque of the motor is not zero, the starting state of the motor is maintained; if the torque of the motor becomes zero, the shutdown mode is entered; when it is detected that the empirical temperature rise value of the IGBT module corresponding to a second time node in the number of time nodes is greater than or equal to the temperature rise margin for the first time, the stall condition of the motor is reported, and the motor is shut down.

Description

Technical Field

[0001] This invention relates to the field of electric motor control technology for new energy vehicles, and more specifically, to a method, device, equipment, and storage medium for stall protection of an electric drive system. Background Technology

[0002] Currently, the power system of new energy vehicles is mainly driven by a motor controller, which is a software-controlled power electronic system. During the startup process of a new energy vehicle's motor, the temperature of the motor controller rises. If a stall condition occurs at this time, i.e., the motor rotor speed is zero or very low, the motor current will increase sharply. Furthermore, due to the very low motor speed, the heat dissipation conditions are very poor, and the internal heat of the motor cannot be transferred to the surrounding cooling medium in time, which may lead to motor burnout. Therefore, stall conditions should be avoided as much as possible during the startup process of new energy vehicle motors. At the same time, the ultimate goal of the startup process of new energy vehicle motors is to achieve safe motor startup. Therefore, it is necessary to provide a refined method that can both avoid motor burnout due to stall conditions and potentially increase the probability of motor startup. Summary of the Invention

[0003] The present invention provides a stall protection method, apparatus, device and storage medium for an electric drive system, to overcome at least one technical problem existing in the prior art.

[0004] According to a first aspect of the present invention, a stall protection method for an electric drive system is provided, the electric drive system being provided with a motor controller, comprising:

[0005] Obtain the initial temperature of the IGBT module in the motor controller when the motor enters the starting state;

[0006] Obtain the temperature threshold that the IGBT module can withstand, and set the difference between the temperature threshold and the starting temperature as the temperature rise margin of the IGBT module;

[0007] Taking the moment when the motor enters the starting state as the zero point, several time nodes are sequentially defined, and the time difference between two adjacent time nodes is a constant value. For any one of the several time nodes, the sum of the accumulated temperature rise empirical value of the previous time node corresponding to that time node and the temperature rise empirical value of the IGBT module within the time difference between that time node and the previous time node is determined as the accumulated temperature rise empirical value of the IGBT module at that time node. Specifically, the calculation method of the temperature rise empirical value within the time interval includes: querying a pre-drawn torque temperature rise curve, determining the empirical temperature rise rate under the starting torque corresponding to the previous time node, and determining the product of the empirical temperature rise rate under the starting torque corresponding to the previous time node and the constant value as the temperature rise empirical value within the time interval. The pre-drawn torque temperature rise curve is used to describe the empirical temperature rise rate of the IGBT module corresponding to different starting torques.

[0008] For the aforementioned time points, if,

[0009] If, under the premise that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that the actual speed of the motor exceeds the speed threshold of the motor in the operating state for the first time at a certain time point among the several time points, then the motor at the first certain time point is marked as entering the normal operation mode.

[0010] Provided that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that there is no time point in the several time points in which the actual speed of the motor exceeds the speed threshold of the motor in the running state, then if the current torque of the motor is not zero, the motor is kept in the starting state; if the current torque of the motor becomes zero, the motor is put into the shutdown mode.

[0011] When the accumulated empirical value of the temperature rise of the IGBT module corresponding to a second time node among the several time nodes is detected to be greater than or equal to the temperature rise margin for the first time, the motor is reported as stalled and the motor is stopped.

[0012] Preferably, the method for obtaining the torque temperature rise curve includes: placing the electric drive system under the heat dissipation conditions required by the technical protocol, using different torques as inputs, and obtaining the empirical temperature rise rate of the IGBT module under each of the different torques; wherein, the heat dissipation conditions required by the technical protocol are used to simulate the heat dissipation conditions of the electric drive system under a real working environment;

[0013] In a Cartesian coordinate system, the relationship between each torque and the corresponding empirical temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

[0014] Preferably, the method for obtaining the torque temperature rise curve includes: conducting a temperature rise simulation test on the IGBT module to obtain the temperature rise rate of the IGBT module under different torque inputs;

[0015] The temperature rise rate corresponding to each of the different torques is increased by a predetermined temperature rise rate margin to obtain the corrected empirical temperature rise rate.

[0016] In a Cartesian coordinate system, the correspondence between each torque and the corresponding corrected empirical temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

[0017] Preferably, if the current torque of the motor is not zero, then maintaining the starting state of the motor specifically includes:

[0018] Calculate the accumulated temperature rise empirical value of the IGBT module at the current moment, and add the accumulated temperature rise empirical value of the IGBT module at the current moment to the initial temperature of the IGBT module to obtain the temperature empirical value of the IGBT module at the current moment.

[0019] Query the IGBT stall temperature limit coefficient curve to obtain the motor torque limit coefficient; multiply the motor torque limit coefficient by the current motor torque to obtain the limited torque;

[0020] Using the restricted torque as the input torque, the motor startup process continues. If the actual speed of the motor exceeds the speed threshold of the motor in the above-running state during the startup process, the motor is calibrated to enter the normal operation mode. If the temperature rise empirical value of the IGBT module is greater than or equal to the temperature rise margin, the motor is reported as stalled and the motor is stopped.

[0021] Preferably, the constant value is between 5 ms and 15 ms.

[0022] According to a second aspect of the present invention, a stall protection device for an electric drive system is provided, comprising:

[0023] The initial temperature acquisition module is used to acquire the initial temperature of the IGBT module in the motor controller when the motor enters the starting state;

[0024] The temperature rise margin calculation module is used to obtain the temperature threshold that the IGBT module can withstand, and set the difference between the temperature threshold and the starting temperature as the temperature rise margin of the IGBT module.

[0025] The temperature rise accumulation experience value calculation module is used to define a number of time nodes sequentially, with the moment when the motor enters the starting state as the time zero point. The time difference between two adjacent time nodes is a constant value. For any one of the time nodes, the sum of the temperature rise accumulation experience value of the previous time node and the temperature rise experience value of the IGBT module within the time difference between the previous time node and the previous time node is determined as the temperature rise accumulation experience value of the IGBT module at that time node. Specifically, the calculation method of the temperature rise experience value within the time interval includes: querying a pre-drawn torque temperature rise curve, determining the experience temperature rise rate under the starting torque corresponding to the previous time node, and determining the product of the experience temperature rise rate under the starting torque corresponding to the previous time node and the constant value as the temperature rise experience value within the time interval. The pre-drawn torque temperature rise curve is used to describe the experience temperature rise rate of the IGBT module corresponding to different starting torques.

[0026] The status monitoring module is used to, for the aforementioned several time points, if...

[0027] If, under the premise that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that the actual speed of the motor exceeds the speed threshold of the motor in the operating state for the first time at a certain time point among the several time points, then the motor at the first certain time point is marked as entering the normal operation mode.

[0028] Provided that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that there is no time point in the several time points in which the actual speed of the motor exceeds the speed threshold of the motor in the running state, then if the current torque of the motor is not zero, the motor is kept in the starting state; if the current torque of the motor becomes zero, the motor is put into the shutdown mode.

[0029] When the accumulated empirical value of the temperature rise of the IGBT module corresponding to a second time node among the several time nodes is detected to be greater than or equal to the temperature rise margin for the first time, the motor is reported as stalled and the motor is stopped.

[0030] Preferably, the device further includes a torque temperature rise curve acquisition module, used to place the electric drive system under the heat dissipation conditions required by the technical protocol, and use different torques as inputs to acquire the temperature rise rate of the IGBT module under each of the different torques; wherein, the heat dissipation conditions required by the technical protocol are used to simulate the heat dissipation conditions of the electric drive system under real working environment;

[0031] In a Cartesian coordinate system, the relationship between each torque and the corresponding temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

[0032] According to a third aspect of the present invention, a computing device is provided, including a storage device and a processor, wherein the storage device is used to store a computer program, and the processor runs the computer program to cause the computing device to perform the steps of a stall protection method for an electric drive system.

[0033] According to a fourth aspect of the present invention, a storage medium is provided, characterized in that it stores a computer program, which, when executed by a processor, implements the steps of a stall protection method for an electric drive system.

[0034] One embodiment of this specification can achieve at least the following beneficial effects: The technical solution of this embodiment uses a torque temperature rise curve to obtain the temperature rise rate of the motor controller under the torque value corresponding to the starting torque. Therefore, compared with the use of a temperature sensor, a more accurate temperature of the IGBT module can be calculated in real time. Then, the motor is started under the premise that the temperature rise of the IGBT module does not exceed the temperature rise margin, avoiding the phenomenon that the IGBT module may burn out due to the delay factor when the temperature of the IGBT module measured by the temperature sensor is used in the prior art. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart illustrating a stall protection method for an electric drive system provided in the embodiments of this specification;

[0037] Figure 2 This is a schematic diagram of the structure of a stall protection device for an electric drive system provided in the embodiments of this specification;

[0038] Figure 3 This is a schematic diagram of the structure of a stall protection device for an electric drive system provided in the embodiments of this specification. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of one or more embodiments of this specification clearer, the technical solutions of one or more embodiments of this specification will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of them. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of one or more embodiments of this specification.

[0040] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another.

[0041] As explained earlier, the power system of current new energy vehicles is mainly driven by a motor controller, which is a software-controlled power electronic system. During the startup process of a new energy vehicle's motor, the temperature of the motor controller rises. If a stall condition occurs at this time, i.e., the motor rotor speed is zero or very low, the motor current will increase sharply. Furthermore, due to the very low motor speed, the heat dissipation conditions are very poor, and the internal heat of the motor cannot be transferred to the surrounding cooling medium in time, which may lead to motor burnout. Therefore, stall conditions should be avoided as much as possible during the startup process of new energy vehicle motors. At the same time, the ultimate goal of the startup process of new energy vehicle motors is to achieve safe motor startup. Therefore, it is necessary to provide a refined method that can both avoid motor burnout due to stall conditions and potentially increase the probability of motor startup.

[0042] In the prior art, there are several methods for stall protection of electric drive systems. For example, patent document CN201110238218.7 discloses "a stall protection and torque limiting method for an electric drive system". In this scheme, the stall torque is linearly limited based on the motor temperature and the feedback temperature of the IGBT of the motor controller. However, this scheme has the following drawbacks: In actual scenarios, the IGBT module of the controller should have the fastest temperature rise when the motor is stalled. Moreover, the current during stall is DC, which is different from the AC current during motor operation. One phase may have a higher current than the other two phases for a long time, and its temperature rises rapidly. The temperature fed back by the temperature sensor that measures the real-time temperature of the IGBT module is very different from the actual temperature of the IGBT. Therefore, when the motor is stalled, it is very likely that the temperature of the motor system, especially the power device (IGBT module) in the motor controller, will rise instantaneously before the detected feedback temperature reaches the preset temperature. Its actual temperature has exceeded the preset temperature, resulting in the controller's protection not being timely and the phenomenon of damage to the control IGBT module.

[0043] Another patent application, CN201811555191.2, discloses "a stall protection method for an electric drive system, a motor controller, and an electric vehicle." In this approach, heat generation is calculated based on the integral of the square of the motor controller's output current over time. If the heat exceeds a preset threshold, stall protection is applied to the motor's output torque. However, this approach has the following drawbacks: using the integral of the square of the current over time to calculate heat generation, and comparing it with a preset value, is inconvenient and unintuitive because heat generation is calculated by multiplying the square of the current by the resistance and then by time, neglecting the influence of resistance. Furthermore, this preset value is also related to the controller's own heat dissipation conditions; for different motor controllers and under different heat dissipation conditions, the preset value needs to be recalculated.

[0044] Another patent application, CN201110180484.9, discloses a "method for motor stall protection in an electric drive system of an electric vehicle." In this scheme, the maximum allowable preset stall value T is obtained based on the stall torque of the motor. If the stall time t is greater than the preset value T, the torque response stops. Each torque can be set with a maximum stall time T. However, if the stall torque of the controller is not constant, false triggering will occur. For example, stalling at the maximum torque allows for 2 seconds of stalling, and stalling at the rated torque allows for 10 seconds of stalling. If stalling at the rated torque for 1.8 seconds and then increasing the stall torque to the peak torque, the stalling time will only be 0.2 seconds because the maximum allowable stall time T has changed. However, the heat generated during the actual 1.8 seconds of stalling at the rated torque is far less than the heat generated during the 1.8 seconds of stalling at the peak torque. Therefore, this scheme will lead to a decrease in the stall capability of the electric drive system.

[0045] To overcome the shortcomings of existing motor stall protection methods, including those described above, this specification provides a stall protection method for an electric drive system. This method estimates the temperature rise based on the remaining temperature margin and the temperature rise condition of the controller at any given time. When the estimated temperature rise exceeds the initially calculated remaining margin, the controller is shut down for protection, thereby starting the motor with the highest possible torque. This increases the probability of successful motor start-up and limits the starting torque of the motor in advance when the IGBT module temperature is high, thus avoiding controller damage that may occur due to insufficient time to take protective measures under high torque starting conditions.

[0046] Next, a stall protection method for an electric drive system provided in the embodiments of the specification will be described in detail with reference to the accompanying drawings.

[0047] Figure 1 This is a flowchart illustrating a stall protection method for an electric drive system provided in an embodiment of this specification. From a programming perspective, the entity executing the process can be an application program integrated into the motor control system.

[0048] like Figure 1 As shown, the process may include the following steps.

[0049] Step 102: Obtain the initial temperature of the IGBT module in the motor controller when the motor enters the start-up state.

[0050] In the embodiments of this specification, the IGBT (Insulated Gate Bipolar Transistor) module represents an insulated gate bipolar transistor, which is a composite fully controllable voltage-driven power semiconductor device composed of a bipolar transistor and an insulated gate field-effect transistor. The initial temperature is used to indicate the initial temperature of the IGBT module when the motor enters the starting state. The starting state indicates that the motor has begun to start. In practical scenarios, one possible way to determine if the motor has entered the starting state is when the current in the motor suddenly changes from zero to flowing; at this point, the motor can be considered to have entered the starting state.

[0051] Step 104: Obtain the temperature threshold that the IGBT module can withstand, and set the difference between the temperature threshold and the starting temperature as the temperature rise margin of the IGBT module.

[0052] In the embodiments of this specification, the temperature threshold is used to represent the highest temperature that the IGBT module can withstand when it can operate normally. In other words, if the temperature continues to rise, the IGBT module may burn out and fail to operate normally. In this step, the difference between the temperature threshold and the starting temperature in step 102 is set as the temperature rise margin of the IGBT module. That is, during subsequent startup, how much higher the temperature of the IGBT module can rise without being damaged by overheating. If the temperature rise exceeds this temperature rise margin, the IGBT module may burn out.

[0053] Step 106: Taking the moment when the motor enters the starting state as the zero point, several time nodes are sequentially defined, and the time difference between two adjacent time nodes is a constant value. For any one of the several time nodes, the sum of the accumulated temperature rise empirical value of the previous time node corresponding to that time node and the temperature rise empirical value of the IGBT module within the time difference between that time node and the previous time node is determined as the accumulated temperature rise empirical value of the IGBT module at that time node. Specifically, the calculation method of the temperature rise empirical value within the time interval includes: querying a pre-drawn torque temperature rise curve, determining the empirical temperature rise rate under the starting torque corresponding to the previous time node, and determining the product of the empirical temperature rise rate under the starting torque corresponding to the previous time node and the constant value as the temperature rise empirical value within the time interval. The pre-drawn torque temperature rise curve is used to describe the empirical temperature rise rate of the IGBT module corresponding to different starting torques.

[0054] In the embodiments of this specification, the time point when the motor enters the starting state is designated as time zero, and several time nodes are defined. For ease of calculation, this embodiment specifies that the time difference between all two adjacent time nodes is a constant value. The magnitude of this constant value can be set according to the actual scenario of the motor starting process. This embodiment does not impose specific restrictions. Of course, in actual scenarios, the time difference between two adjacent time nodes may not be a constant value.

[0055] In this embodiment, the accumulated temperature rise experience value at a certain time point can refer to the estimated value of the temperature rise of the IGBT module at that certain time point compared to the initial temperature of the IGBT module obtained in step 102, that is, how much the temperature of the IGBT module has increased. It should be noted that, based on the defects existing in the technical solution of the patent document with patent number CN201110238218.7 described above, the technical solution of this application does not use the temperature measurement value of the temperature sensor as the temperature value of the IGBT module. Instead, it calculates the accumulated temperature rise value of the IGBT module under different starting torques during the motor start-up process based on the method of querying the torque temperature rise curve introduced below. The temperature rise experience value over a time interval can refer to the temperature rise value of the IGBT module in the time period between two adjacent time points, that is, how much higher the temperature of the IGBT module is at the later time point than the temperature at the previous time point. The calculation of this value also needs to be based on the torque temperature rise curve introduced below.

[0056] The torque-temperature rise curve described above is used to describe the empirical temperature rise rate of the IGBT module corresponding to different starting torques. That is, for a specific torque value, by consulting this curve, we can obtain the temperature rise rate of the IGBT module after that specific torque value is input to the motor, i.e., how much the temperature rises per unit time. For example, the term "interval temperature rise empirical value" was introduced earlier. Assuming there are two time nodes, t1 and t2, the interval temperature rise empirical value ΔT of the IGBT module between these two time nodes can be calculated by the formula dTemp*(t2-t1), i.e., ΔT=dTemp*(t2-t1), where the symbol dTemp represents the temperature rise rate of the IGBT module at time node t1. The magnitude of this value can be obtained by consulting the torque-temperature rise curve based on the starting torque at time node t1.

[0057] In this embodiment, the torque-temperature rise curve is used to query the temperature rise rate of the IGBT module after a given starting torque, instead of using a temperature sensor to measure the temperature of the IGBT module in real time as described in the prior art. This allows for a more accurate calculation of the actual temperature of the IGBT module.

[0058] Step 108: For the aforementioned time points, if,

[0059] If, under the premise that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that the actual speed of the motor exceeds the speed threshold of the motor in the operating state for the first time at a certain time point among the several time points, then the motor at the first certain time point is marked as entering the normal operation mode.

[0060] Provided that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that there is no time point in the several time points in which the actual speed of the motor exceeds the speed threshold of the motor in the running state, then if the current torque of the motor is not zero, the motor is kept in the starting state; if the current torque of the motor becomes zero, the motor is put into the shutdown mode.

[0061] When the accumulated empirical value of the temperature rise of the IGBT module corresponding to a second time node among the several time nodes is detected to be greater than or equal to the temperature rise margin for the first time, the motor is reported as stalled and the motor is stopped.

[0062] In the embodiments of this specification, the specific value of the motor speed threshold during operation can be set by technicians according to actual conditions. This embodiment of the invention does not impose such a limitation. If the motor speed exceeds this threshold, the motor is considered to have successfully started and can be marked as entering normal operating mode. If the motor speed is less than this threshold, the motor is considered not to have started successfully. Provided that the temperature rise experience value of the IGBT module is less than the temperature rise margin, the motor can continue to be started based on the torque value set by the operator. Furthermore, in this embodiment, if the motor continues to be started when the temperature rise experience value of the IGBT module is greater than or equal to the temperature rise margin, it will burn out due to excessive temperature. In this case, a stall condition report should be submitted, and the motor should be stopped to protect its safety.

[0063] It should be understood that in the methods described in one or more embodiments of this specification, the order of some steps may be adjusted according to actual needs, or some steps may be omitted.

[0064] The technical solution in this specification uses a torque-temperature rise curve to obtain the temperature rise rate of the motor controller under the torque value corresponding to the starting torque. Therefore, compared with using a temperature sensor, it can calculate the temperature of the IGBT module more accurately in real time. Then, the motor is started under the premise that the temperature rise of the IGBT module does not exceed the temperature rise margin, thus avoiding the phenomenon of IGBT module burnout that may be caused by the delay factor when the temperature of the IGBT module measured by the temperature sensor is used in the prior art.

[0065] based on Figure 2 In addition to the method described herein, this specification also provides some specific implementation schemes of the method, which will be described below.

[0066] This specification provides several methods for obtaining torque temperature rise curves, which are described below.

[0067] In an optional embodiment, the method for obtaining the torque temperature rise curve includes: placing the electric drive system under the heat dissipation conditions required by the technical protocol, using different torques as input, and obtaining the temperature rise rate of the IGBT module under each of the different torques; wherein, the heat dissipation conditions required by the technical protocol are used to simulate the heat dissipation conditions of the electric drive system under a real working environment;

[0068] In a Cartesian coordinate system, the relationship between each torque and the corresponding empirical temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

[0069] It should be noted that in real-world scenarios, the starting torque value of a motor is a dynamically changing process during startup. Therefore, it is necessary to obtain the empirical temperature rise rate of the IGBT module under different starting torque values.

[0070] In an optional embodiment, the method for obtaining the torque temperature rise curve includes: performing a temperature rise simulation test on the IGBT module to obtain the temperature rise rate of the IGBT module under different torque inputs;

[0071] The temperature rise rate corresponding to each of the different torques is increased by a predetermined temperature rise rate margin to obtain the corrected empirical temperature rise rate.

[0072] In a Cartesian coordinate system, the correspondence between each torque and the corresponding corrected empirical temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

[0073] In this embodiment, compared to the method of obtaining the torque temperature rise curve in the previous embodiment, in addition to using a different method to obtain the torque temperature rise curve, a predetermined temperature rise rate margin is added to the temperature rise rate corresponding to each torque, resulting in a corrected empirical temperature rise rate. This allows the scheme to have a certain margin when calculating the accumulated temperature rise empirical value of the IGBT module, compared to the accumulated temperature rise value of the IGBT module. In other words, it can more safely protect the motor from stall during startup. It should be noted that the specific size of this predetermined temperature rise rate margin should be controlled within a reasonable range and should not be too large. Otherwise, the corrected empirical temperature rise rate of the IGBT module will have a large error compared to the actual temperature rise rate.

[0074] In an optional embodiment, maintaining the starting state of the motor if the current torque of the motor is not zero specifically includes:

[0075] Calculate the empirical temperature rise value of the IGBT module at the current moment, and add the empirical temperature rise value of the IGBT module at the current moment to the initial temperature of the IGBT module to obtain the empirical temperature value of the IGBT module at the current moment.

[0076] Query the IGBT stall temperature limit coefficient curve to obtain the motor torque limit coefficient; multiply the motor torque limit coefficient by the current motor torque to obtain the limited torque;

[0077] Using the restricted torque as the input torque, the motor startup process continues. If the actual speed of the motor exceeds the speed threshold of the motor in the above-running state during the startup process, the motor is calibrated to enter the normal operation mode. If the temperature rise empirical value of the IGBT module is greater than or equal to the temperature rise margin, the motor is reported as stalled and the motor is stopped.

[0078] In an optional embodiment, the time difference between two adjacent time points described above, which is a constant value, is between 5ms and 15ms.

[0079] Based on the same idea, embodiments of this specification also provide apparatus corresponding to the above methods. Figure 3 The embodiments provided in this specification correspond to Figure 1 A schematic diagram of a stall protection device for an electric drive system. Figure 3 As shown, the device may include:

[0080] The starting temperature acquisition module 202 is used to acquire the starting temperature of the IGBT module in the motor controller when the motor enters the starting state.

[0081] Temperature rise margin calculation module 204 is used to obtain the temperature threshold that the IGBT module can withstand, and set the difference between the temperature threshold and the starting temperature as the temperature rise margin of the IGBT module.

[0082] The temperature rise accumulation experience value calculation module 206 is used to define a number of time nodes sequentially, with the moment when the motor enters the starting state as the time zero point. The time difference between two adjacent time nodes is a constant value. For any one of the time nodes, the sum of the temperature rise accumulation experience value of the previous time node corresponding to the given time node and the temperature rise experience value of the IGBT module within the time difference between the given time node and the previous time node is determined as the temperature rise accumulation experience value of the IGBT module at the given time node. Specifically, the calculation method of the temperature rise experience value within the time interval includes: querying a pre-drawn torque temperature rise curve, determining the experience temperature rise rate under the starting torque corresponding to the previous time node, and determining the product of the experience temperature rise rate under the starting torque corresponding to the previous time node and the constant value as the temperature rise experience value within the time interval. The pre-drawn torque temperature rise curve is used to describe the experience temperature rise rate of the IGBT module corresponding to different starting torques.

[0083] The status monitoring module 208 is used to, for the aforementioned several time points, if...

[0084] If, under the premise that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that the actual speed of the motor exceeds the speed threshold of the motor in the operating state for the first time at a certain time point among the several time points, then the motor at the first certain time point is marked as entering the normal operation mode.

[0085] Provided that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that there is no time point in the several time points in which the actual speed of the motor exceeds the speed threshold of the motor in the running state, then if the current torque of the motor is not zero, the motor is kept in the starting state; if the current torque of the motor becomes zero, the motor is put into the shutdown mode.

[0086] When the accumulated empirical value of the temperature rise of the IGBT module corresponding to a second time node among the several time nodes is detected to be greater than or equal to the temperature rise margin for the first time, the motor is reported as stalled and the motor is stopped.

[0087] It is understood that the modules mentioned above refer to computer programs or program segments used to perform one or more specific functions. Furthermore, the distinction between these modules does not imply that the actual program code must also be separate.

[0088] In an optional embodiment, the device may further include a torque temperature rise curve acquisition module, which is used to place the electric drive system under the heat dissipation conditions required by the technical protocol, and use different torques as inputs to acquire the temperature rise rate of the IGBT module under each of the different torques; wherein, the heat dissipation conditions required by the technical protocol are used to simulate the heat dissipation conditions of the electric drive system under real working environment.

[0089] In a Cartesian coordinate system, the relationship between each torque and the corresponding temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

[0090] Figure 3 This is a schematic diagram of the structure of a stall protection device for an electric drive system provided in the embodiments of this specification. Figure 3 As shown, this hardware device may include:

[0091] At least one processor 310; and,

[0092] Memory 330 communicatively connected to the at least one processor; wherein,

[0093] The memory 330 stores instructions 320 that can be executed by the at least one processor 310 to enable the hardware device to perform the stall protection method for the electric drive system described above.

[0094] Meanwhile, the present invention also provides a computing device, including a storage device and a processor, wherein the storage device is used to store a computer program, and the processor runs the computer program to enable the computing device to perform the steps in the stall protection method for the electric drive system described above.

[0095] In addition, the present invention also provides a storage medium storing a computer program used in the computing device described above, which, when executed by a processor, implements the steps of the stall protection method for the electric drive system described above.

[0096] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0097] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0098] Based on the same idea, this specification also provides devices corresponding to the above methods in its embodiments.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of stall protection for an electric drive system in which a motor controller is provided, characterised in that, The method includes: Obtain the initial temperature of the IGBT module in the motor controller when the motor enters the starting state; Obtain the temperature threshold that the IGBT module can withstand, and set the difference between the temperature threshold and the starting temperature as the temperature rise margin of the IGBT module; Taking the moment when the motor enters the starting state as the zero point, several time nodes are sequentially defined, with the time difference between any two adjacent time nodes being a constant value. For any given time node, the sum of the accumulated temperature rise empirical value of the previous time node and the temperature rise empirical value of the IGBT module within the time difference between the given time node and the previous time node is determined as the accumulated temperature rise empirical value of the IGBT module at that given time node. Specifically, the calculation method for the temperature rise empirical value within the time interval includes: querying a pre-drawn torque temperature rise curve to determine the empirical temperature rise rate under the starting torque corresponding to the previous time node; and multiplying the empirical temperature rise rate under the starting torque corresponding to the previous time node with the constant value to determine the temperature rise empirical value within the time interval. The pre-drawn torque temperature rise curve is used to describe the empirical temperature rise rate of the IGBT module corresponding to different starting torques. For the aforementioned time points, if, If, under the premise that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that the actual speed of the motor exceeds the speed threshold of the motor in the operating state for the first time at a certain time point among the several time points, then the motor at the first certain time point is marked as entering the normal operation mode. Provided that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that there is no time point in the several time points in which the actual speed of the motor exceeds the speed threshold of the motor in the running state, then if the current torque of the motor is not zero, the motor is kept in the starting state; if the current torque of the motor becomes zero, the motor is put into the shutdown mode. When the accumulated empirical value of the temperature rise of the IGBT module corresponding to a second time node among the several time nodes is detected to be greater than or equal to the temperature rise margin for the first time, the motor is reported as stalled and the motor is stopped.

2. The method of claim 1, wherein, The method for obtaining the torque temperature rise curve includes: placing the electric drive system under the heat dissipation conditions required by the technical protocol, using different torques as inputs, and obtaining the empirical temperature rise rate of the IGBT module under each of the different torques; wherein, the heat dissipation conditions required by the technical protocol are used to simulate the heat dissipation conditions of the electric drive system under a real working environment; In a Cartesian coordinate system, the relationship between each torque and the corresponding empirical temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

3. The method of claim 1, wherein, The method for obtaining the torque temperature rise curve includes: conducting a temperature rise simulation test on the IGBT module to obtain the temperature rise rate of the IGBT module under different torque inputs; The temperature rise rate corresponding to each of the different torques is increased by a predetermined temperature rise rate margin to obtain the corrected empirical temperature rise rate. In a Cartesian coordinate system, the correspondence between each torque and the corresponding corrected empirical temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

4. The method of claim 1, wherein, If the current torque of the motor is not zero, then maintaining the starting state of the motor specifically includes: Calculate the accumulated temperature rise empirical value of the IGBT module at the current moment, and add the accumulated temperature rise empirical value of the IGBT module at the current moment to the initial temperature of the IGBT module to obtain the temperature empirical value of the IGBT module at the current moment. Query the IGBT stall temperature limit coefficient curve to obtain the motor torque limit coefficient; multiply the motor torque limit coefficient by the current motor torque to obtain the limited torque; Using the restricted torque as the input torque, the motor startup process continues. If the actual speed of the motor exceeds the speed threshold of the motor in the above-running state during the startup process, the motor is calibrated to enter the normal operation mode. If the temperature rise empirical value of the IGBT module is greater than or equal to the temperature rise margin, the motor is reported as stalled and the motor is stopped.

5. The method according to claim 1, characterized in that, The constant value ranges from 5ms to 15ms.

6. A stall protection device for an electric drive system, characterized in that, include: The initial temperature acquisition module is used to acquire the initial temperature of the IGBT module in the motor controller when the motor enters the starting state; The temperature rise margin calculation module is used to obtain the temperature threshold that the IGBT module can withstand, and set the difference between the temperature threshold and the starting temperature as the temperature rise margin of the IGBT module. The temperature rise accumulation experience value calculation module is used to define a number of time nodes sequentially, with the moment when the motor enters the starting state as the time zero point. The time difference between two adjacent time nodes is a constant value. For any one of the time nodes, the sum of the temperature rise accumulation experience value of the previous time node and the temperature rise experience value of the IGBT module within the time interval between the previous time node and the previous time node is determined as the temperature rise accumulation experience value of the IGBT module at that time node. Specifically, the calculation method of the temperature rise experience value within the time interval includes: querying a pre-drawn torque temperature rise curve, determining the experience temperature rise rate under the starting torque corresponding to the previous time node, and determining the product of the experience temperature rise rate under the starting torque corresponding to the previous time node and the constant value as the temperature rise experience value within the time interval. The pre-drawn torque temperature rise curve is used to describe the experience temperature rise rate of the IGBT module corresponding to different starting torques. The status monitoring module is used to, for the aforementioned several time points, if... If, under the premise that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that the actual speed of the motor exceeds the speed threshold of the motor in the operating state for the first time at a certain time point among the several time points, then the motor at the first certain time point is marked as entering the normal operation mode. Provided that the accumulated temperature rise of the IGBT module is less than the temperature rise margin, if it is detected that there is no time point in the several time points in which the actual speed of the motor exceeds the speed threshold of the motor in the running state, then if the current torque of the motor is not zero, the motor is kept in the starting state; if the current torque of the motor becomes zero, the motor is put into the shutdown mode. When the accumulated empirical value of the temperature rise of the IGBT module corresponding to a second time node among the several time nodes is detected to be greater than or equal to the temperature rise margin for the first time, the motor is reported as stalled and the motor is stopped.

7. The apparatus as claimed in claim 6, characterized in that, The device further includes a torque temperature rise curve acquisition module, which is used to place the electric drive system under the heat dissipation conditions required by the technical protocol, and use different torques as inputs to obtain the temperature rise rate of the IGBT module under each of the different torques; wherein, the heat dissipation conditions required by the technical protocol are used to simulate the heat dissipation conditions of the electric drive system under real working environment. In a Cartesian coordinate system, the relationship between each torque and the corresponding temperature rise rate is plotted to obtain several scattered points. Curve fitting is then performed on these scattered points to obtain the torque temperature rise curve.

8. A computing device, characterized in that, The device includes a storage device and a processor, the storage device being used to store a computer program, and the processor running the computer program to cause the computing device to perform the steps of the method according to any one of claims 1-5.

9. A storage medium, characterized in that, It stores a computer program used in the computing device of claim 8, which, when executed by a processor, implements the steps of the method of any one of claims 1-5.

Images