PWM torque control method, motor controller and readable storage medium

Abstract

The invention provides a PWM (Pulse Width Modulation) torque control method, a motor controller and a readable storage medium. The method comprises the following steps: acquiring original rotating speed information of a motor under the action of PWM torque; filtering the original rotating speed information of the motor to obtain inherent frequency rotating speed fluctuation information of the whole vehicle; inhibition torque is determined according to the inherent frequency rotating speed fluctuation information of the whole vehicle; and taking a superposition result of the inhibition torque and the whole vehicle demand torque as a target input torque of a PWM torque strategy. According to the method, the fluctuation range of the whole vehicle can be effectively reduced under the condition that the PWM torque function of the whole vehicle is started to improve the efficiency of the electric drive system, and then the drivability of the whole vehicle can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to a PWM torque control method, a motor controller and a readable storage medium. Background Art

[0002] When the vehicle command torque is lower than the optimal torque for the electric drive system, the command torque can be equivalent to a PWM torque (pulse width modulation torque) with a certain duty cycle output through a torque-time equivalent pulse width modulation method, where the high level is the positive optimal efficiency torque for the electric drive, and the low level is the electric drive off state or the negative optimal efficiency torque state. This PWM torque output method can effectively improve the efficiency of the electric drive system, thereby saving costs, but it will bring the following two problems to the vehicle's drivability:

[0003] 1. PWM torque response is fast and discontinuous, which can easily cause the vehicle to vibrate near the natural frequency and affect the driving feel.

[0004] Please refer to Figure 1 , which is a schematic diagram of speed fluctuation under the action of PWM torque. Figure 1 As shown in the figure, under the action of PWM torque, there are generally two frequencies of speed fluctuations in the electric drive or wheel end: one is the speed fluctuation with a frequency of about 20Hz to 60Hz caused by the PWM torque itself. The amplitude of this fluctuation is relatively small and the frequency is high. It is basically not felt after being filtered by the vehicle transmission system; the other is the speed fluctuation caused by the inherent vibration of the vehicle structure or transmission system. This speed fluctuation is easily excited after the action of PWM torque. The amplitude of this speed fluctuation is large, generally 2 to 3 times more than the speed fluctuation caused by PWM torque itself, and the frequency is low, generally around 6Hz to 12Hz, and is easy to be felt.

[0005] 2. The PWM torque frequency is relatively high, generally around 20Hz to 60Hz. When a fixed frequency is used under certain working conditions, the electric drive system is prone to vibration and then radiate noise of the same frequency, affecting the driving feel.

[0006] It should be noted that the information disclosed in the background technology section of the invention is only intended to deepen the understanding of the general background technology of the invention, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0007] The purpose of the present invention is to provide a PWM torque control method, a motor controller and a readable storage medium, which can effectively reduce the fluctuation amplitude of the whole vehicle when the PWM torque function of the whole vehicle is turned on to improve the efficiency of the electric drive system, thereby effectively improving the drivability of the whole vehicle.

[0008] To achieve the above object, the present invention provides a PWM torque control method, comprising:

[0009] Get the original speed information of the motor under the action of PWM torque;

[0010] Filtering the original speed information of the motor to obtain the natural frequency speed fluctuation information of the whole vehicle;

[0011] Determining the suppression torque according to the natural frequency speed fluctuation information of the whole vehicle;

[0012] The superposition result of the suppression torque and the vehicle demand torque is used as the target input torque of the PWM torque strategy.

[0013] Optionally, filtering the original speed information of the motor to obtain the natural frequency speed fluctuation information of the whole vehicle includes:

[0014] A low-pass filter is used to perform low-pass filtering on the original speed information of the motor to obtain low-frequency speed information of the motor, wherein the cut-off frequency of the low-pass filter is less than the minimum value of the PWM torque frequency and greater than the maximum value of the natural frequency of the whole vehicle;

[0015] A high-pass filter is used to perform high-pass filtering on the low-frequency speed information of the motor to obtain the speed fluctuation information of the natural frequency of the whole vehicle, wherein the cut-off frequency of the high-pass filter is less than the minimum value of the natural frequency of the whole vehicle.

[0016] Optionally, the PWM torque control method further includes:

[0017] A phase corrector is used to perform phase correction on the low-frequency speed information of the motor or the natural frequency speed fluctuation information of the whole vehicle.

[0018] Optionally, determining the suppression torque according to the natural frequency speed fluctuation information of the whole vehicle includes:

[0019] Determine the torque coefficient according to the original motor speed information, the PWM torque frequency information, and the mapping relationship between the motor speed, the PWM torque frequency, and the torque coefficient acquired in advance;

[0020] The suppression torque is determined according to the vehicle natural frequency speed fluctuation information and the torque coefficient.

[0021] Optionally, determining the suppression torque according to the vehicle natural frequency speed fluctuation information and the torque coefficient includes:

[0022] Inverting the natural frequency speed fluctuation information of the whole vehicle;

[0023] Determining the compensation torque according to the inverted natural frequency speed fluctuation information of the whole vehicle and the torque coefficient;

[0024] The compensation torque is limited according to a preset upper limit torque and a preset lower limit torque to obtain a restraining torque.

[0025] Optionally, the PWM torque control method further includes:

[0026] When the absolute value of the vehicle's natural frequency speed fluctuation value is greater than the preset speed fluctuation threshold, the PWM torque strategy is turned off, and after a preset delay time, it is determined whether the PWM torque strategy needs to be turned on.

[0027] Optionally, the PWM torque control method further includes:

[0028] Perform frequency jitter processing on the frequency of PWM torque.

[0029] Optionally, the frequency jittering process on the frequency of the PWM torque includes:

[0030] Determine the frequency jitter coefficient according to the current number of action cycles of the PWM torque and the mapping relationship between the number of action cycles of the PWM torque acquired in advance and the frequency jitter coefficient;

[0031] The frequency of the next action cycle of the PWM torque is determined according to the initial frequency of the PWM torque strategy and the frequency jitter coefficient.

[0032] Optionally, the frequency of the PWM torque after frequency jittering processing is greater than twice the natural frequency of the vehicle.

[0033] To achieve the above object, the present invention further provides a motor controller, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the PWM torque control method described above is implemented.

[0034] To achieve the above object, the present invention further provides a readable storage medium, wherein the readable storage medium stores a computer program, and when the computer program is executed by a processor, the PWM torque control method described above is implemented.

[0035] Compared with the prior art, the PWM torque control method, motor controller and readable storage medium provided by the present invention have the following beneficial effects:

[0036] The PWM torque control method provided by the present invention first obtains the original speed information of the motor under the action of PWM torque; then filters the original speed information of the motor to obtain the speed fluctuation information of the natural frequency of the whole vehicle; then determines the suppression torque according to the speed fluctuation information of the natural frequency of the whole vehicle; finally, the superposition result of the suppression torque and the required torque of the whole vehicle is used as the target input torque of the PWM torque strategy. It can be seen that by adopting the PWM torque control method provided by the present invention, the high-frequency speed fluctuation caused by the PWM torque can be filtered out, and only the speed fluctuation near the natural frequency of the whole vehicle (the speed fluctuation of the natural frequency of the whole vehicle) is retained. By applying a suppression torque that is proportional to and opposite to the speed fluctuation near the fixed frequency of the whole vehicle for control, the whole vehicle can effectively reduce the fluctuation amplitude of the whole vehicle when the PWM torque function is turned on to improve the efficiency of the electric drive system, thereby effectively improving the drivability of the whole vehicle.

[0037] Since the motor controller and the readable storage medium provided by the present invention belong to the same inventive concept as the PWM torque control method provided by the present invention, the motor controller and the readable storage medium provided by the present invention at least have all the beneficial effects of the PWM torque control method provided by the present invention. For details, please refer to the relevant description above, so the beneficial effects of the motor controller and the readable storage medium provided by the present invention will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of speed fluctuation under the action of PWM torque;

[0039] Figure 2 A schematic flow chart of a PWM torque control method provided in one embodiment of the present invention;

[0040] Figure 3 A schematic diagram of an original motor speed signal provided for a specific example of the present invention;

[0041] Figure 4 A schematic diagram of a motor speed signal after low-pass filtering provided in a specific example of the present invention;

[0042] Figure 5 A schematic diagram of a motor speed signal after high-pass filtering provided in a specific example of the present invention;

[0043] Figure 6 A schematic diagram of PWM torque frequency jittering provided for a specific example of the present invention;

[0044] Figure 7 A schematic diagram of a frequency jitter sequence provided for a specific example of the present invention;

[0045] Figure 8A schematic diagram of the overall process of a PWM torque control method provided by one embodiment of the present invention;

[0046] Fig. 9 A schematic block diagram of a motor controller provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The PWM torque control method, motor controller and readable storage medium proposed in the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose provided by the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Any modification of the structure, change in the proportional relationship or adjustment of the size, under the condition that the effects and purposes that can be achieved by the present invention are the same or similar, should still fall within the scope of the technical content disclosed by the present invention.

[0048] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements. The singular forms "a", "an" and "the" include plural objects, the term "or" is generally used in a sense including "and / or", the term "several" is generally used in a sense including "at least one", and the term "at least two" is generally used in a sense including "two or more". In addition, the terms "first", "second" and "third" are used for descriptive purposes only and are not to be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features.

[0049] In addition, 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 invention. 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 more 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.

[0050] Based on this, the core idea of ​​the present invention is to provide a PWM torque control method, a motor controller and a readable storage medium, which can effectively reduce the fluctuation amplitude of the whole vehicle when the PWM torque function is turned on to improve the efficiency of the electric drive system, thereby effectively improving the drivability of the whole vehicle.

[0051] It should be noted that the PWM torque control method provided by the present invention can be applied to the motor controller provided by the present invention, and the motor controller provided by the present invention can be configured on electric vehicles, including but not limited to electric vehicles such as sport utility vehicles (SUVs), buses, trucks, and passenger vehicles including various commercial vehicles, wherein the motor controller can be a hardware device with various operating systems.

[0052] To realize the above idea, the present invention provides a PWM torque control method, please refer to Figure 2 , which is a flow chart of a PWM torque control method provided by an embodiment of the present invention. Figure 2 As shown, the PWM torque control method includes the following steps:

[0053] Step S100: obtaining original motor speed information under the action of PWM torque.

[0054] Step S200: filtering the original speed information of the motor to obtain the natural frequency speed fluctuation information of the whole vehicle.

[0055] Step S300: determining the suppression torque according to the natural frequency speed fluctuation information of the whole vehicle.

[0056] Step S400: taking the superposition result of the suppression torque and the vehicle demand torque as the target input torque of the PWM torque strategy.

[0057] It can be seen that by adopting the PWM torque control method provided by the present invention, the high-frequency speed fluctuations caused by the PWM torque can be filtered out, and only the speed fluctuations near the natural frequency of the whole vehicle (the speed fluctuations at the natural frequency of the whole vehicle) are retained. By applying a suppression torque that is proportional to and opposite to the speed fluctuations near the fixed frequency of the whole vehicle for control, the whole vehicle can effectively reduce the fluctuation amplitude of the whole vehicle when the PWM torque function is turned on to improve the efficiency of the electric drive system, thereby effectively improving the drivability of the whole vehicle.

[0058] Specifically, when the PWM torque acts, the motor controller can collect the original speed signal nem (motor speed before filtering) of the motor at a sampling frequency of more than 100 Hz. It should be noted that, as those skilled in the art can understand, the target input torque of the PWM torque strategy is equal to the sum of the suppression torque and the required torque of the vehicle. It should also be noted that, as those skilled in the art can understand, the obtained original motor speed information refers to the real-time motor speed information collected by the motor controller, and the obtained original motor speed information changes in real time.

[0059] In some exemplary implementations, the step S200 of filtering the original motor speed information to obtain the natural frequency speed fluctuation information of the whole vehicle includes:

[0060] Step S210: low-pass filter the original motor speed information to obtain low-frequency motor speed information, wherein the cut-off frequency of the low-pass filter is less than the minimum value of the PWM torque frequency and greater than the maximum value of the vehicle's natural frequency.

[0061] Step S220: Use a high-pass filter to perform high-pass filtering on the low-frequency speed information of the motor to obtain the speed fluctuation information of the natural frequency of the whole vehicle, wherein the cut-off frequency of the high-pass filter is less than the minimum value of the natural frequency of the whole vehicle.

[0062] Specifically, please refer to Figures 3 to 5 ,in, Figure 3 A schematic diagram of an original motor speed signal provided for a specific example of the present invention; Figure 4 A schematic diagram of a motor speed signal after low-pass filtering provided in a specific example of the present invention; Figure 5 A schematic diagram of a motor speed signal after high-pass filtering is provided for a specific example of the present invention. Figure 3 and Figure 4 As shown, by using a low-pass filter with a cut-off frequency less than the minimum value of the PWM torque frequency and greater than the maximum value of the vehicle fixed frequency to filter the original motor speed information, the high-frequency speed fluctuation caused by the PWM torque can be effectively filtered out. Figure 4 and Figure 5As shown, by using a high-pass filter with a cutoff frequency less than the minimum value of the vehicle's natural frequency to perform high-pass filtering on the motor's low-frequency information, the speed fluctuation near the vehicle's natural frequency can be effectively retained. In addition, since the speed fluctuation frequency caused by PWM torque is relatively high, the amplitude is relatively small relative to the speed fluctuation near the vehicle's natural frequency. Since this part of the speed fluctuation (speed fluctuation caused by PWM torque) is at the same frequency as the PWM torque and cannot be suppressed by applying reverse torque, and is basically not felt after being filtered by the vehicle system, it can be filtered out by a low-pass filter to prevent interference with subsequent filtering.

[0063] It should be noted that, as those skilled in the art can understand, the present invention does not limit the specific types of the low-pass filter and the high-pass filter. The low-pass filter and the high-pass filter can be but are not limited to digital filters, bandpass filters, notch filters and other filters.

[0064] In some exemplary embodiments, before executing step S220 and using a high-pass filter to perform high-pass filtering on the low-frequency speed information of the motor, the PWM torque control method further includes the following steps:

[0065] Step S211: using a phase corrector to perform phase correction on the low-frequency speed information of the motor.

[0066] Correspondingly, the step S220 uses a high-pass filter to perform high-pass filtering on the low-frequency speed information of the motor to obtain the natural frequency speed fluctuation information of the whole vehicle, specifically:

[0067] A high-pass filter is used to perform high-pass filtering on the low-frequency speed information of the motor after phase correction to obtain the natural frequency speed fluctuation information of the whole vehicle.

[0068] Therefore, by using a phase corrector to perform phase correction on the low-frequency speed information of the motor, the phase lag and lead phenomenon caused by the delay effect of the low-pass filter can be corrected, thereby ensuring the accuracy of the acquired vehicle's natural frequency speed fluctuation information and effectively preventing the speed fluctuation from being aggravated by errors in suppressing the direction and magnitude of the torque.

[0069] It should be noted that for more information on how to use a phase corrector to perform phase correction on the low-frequency speed information of the motor, reference can be made to relevant content in the field of signal processing known to those skilled in the art, and will not be elaborated here.

[0070] In some other exemplary embodiments, before executing step S300 and determining the suppression torque according to the natural frequency speed fluctuation information of the whole vehicle, the PWM torque control method further includes the following steps:

[0071] Step S221: Use a phase corrector to perform phase correction on the natural frequency speed fluctuation information of the whole vehicle.

[0072] Correspondingly, the step S300, determining the restraining torque according to the natural frequency speed fluctuation information of the whole vehicle, is specifically:

[0073] The suppression torque is determined according to the phase-corrected natural frequency speed fluctuation information of the whole vehicle.

[0074] Therefore, by using a phase corrector to perform phase correction on the vehicle's natural frequency speed fluctuation information, the phase lag and advance phenomenon caused by the delay effect of the high-pass filter can be corrected, thereby ensuring the accuracy of the suppression torque determined based on the corrected vehicle's natural frequency speed fluctuation information, and effectively preventing the speed fluctuation from being worsened due to errors in the direction and size of the suppression torque.

[0075] In some exemplary implementations, the step S300 of determining the restraining torque according to the natural frequency speed fluctuation information of the whole vehicle includes:

[0076] Step S310: determine the torque coefficient according to the original motor speed information, the PWM torque frequency information, and the pre-acquired mapping relationship between the motor speed, the PWM torque frequency, and the torque coefficient.

[0077] Step S320: determining the suppression torque according to the vehicle natural frequency speed fluctuation information and the torque coefficient.

[0078] Specifically, the mapping relationship between the motor speed, PWM torque frequency and torque coefficient can be recorded in a torque coefficient table, and the torque coefficient table can be queried according to the original motor speed and the current PWM torque frequency to obtain the torque coefficient corresponding to the original motor speed and the current PWM torque frequency. It should be noted that, as can be understood by those skilled in the art, the mapping relationship between the motor speed, PWM torque frequency and torque coefficient can be obtained by actual vehicle calibration.

[0079] In some exemplary implementations, the step S320, determining the restraining torque according to the vehicle natural frequency speed fluctuation information and the torque coefficient, includes:

[0080] Step S321, invert the vehicle's natural frequency speed fluctuation information.

[0081] Step S322: Determine the compensation torque according to the inverted vehicle natural frequency speed fluctuation information and the torque coefficient.

[0082] Step S323: limiting the compensation torque according to the preset upper limit torque and the preset lower limit torque to obtain the suppression torque.

[0083] Specifically, the compensation torque can be obtained by multiplying the inverse result of the vehicle's natural frequency speed fluctuation value with the determined torque coefficient; by setting the upper and lower limits of the compensation torque according to the preset upper limit torque and the preset lower limit torque, it can be ensured that the obtained suppression torque is greater than or equal to the preset lower limit torque and less than or equal to the preset upper limit torque. It should be noted that, as those skilled in the art can understand, when the calculated compensation torque is less than the preset lower limit torque, the preset lower limit torque is used as the suppression torque; when the calculated compensation torque is greater than or equal to the preset lower limit torque and less than or equal to the preset upper limit torque, the compensation torque is used as the suppression torque; when the calculated compensation torque is greater than the preset upper limit torque, the preset upper limit torque is used as the suppression torque. It should be noted that, as those skilled in the art can understand, the specific values ​​of the preset upper limit torque and the preset lower limit torque can be set according to actual conditions, and the present invention does not limit the specific values ​​of the preset upper limit torque and the preset lower limit torque.

[0084] It should also be noted that, as can be understood by those skilled in the art, in some other embodiments, closed-loop control can also be performed based on the natural frequency speed fluctuation information of the whole vehicle to determine the suppressed torque. Specifically, as to how to perform closed-loop control based on the natural frequency speed fluctuation information of the whole vehicle to determine the specific content of the suppressed torque, reference can be made to the relevant content in the field of PID controller technology known to those skilled in the art, which will not be elaborated here.

[0085] In some exemplary embodiments, the PWM torque control method further includes the following steps:

[0086] Step S500: when the absolute value of the vehicle's natural frequency speed fluctuation value is greater than a preset speed fluctuation threshold, the PWM torque strategy is turned off, and after a preset delay time, it is determined whether the PWM torque strategy needs to be turned on.

[0087] Therefore, by turning off the PWM torque strategy when the absolute value of the frequency speed fluctuation value of the whole vehicle is greater than the preset speed fluctuation threshold, and judging whether the PWM torque strategy needs to be turned on after a preset delay, the problem of unclear speed fluctuation suppression effect and large vehicle shaking caused by bumpy roads or sudden acceleration or deceleration conditions can be effectively avoided, thereby improving the robustness of the PWM torque control method provided by the present invention.

[0088] It should be noted that, as can be understood by those skilled in the art, after the preset delay time, if the absolute value of the vehicle's natural frequency speed fluctuation value at this time is less than or equal to the preset speed fluctuation threshold, the PWM torque strategy is restarted. It should also be noted that, as can be understood by those skilled in the art, the present invention does not limit the specific values ​​of the preset speed fluctuation threshold and the preset time, the specific value of the preset speed fluctuation threshold can be set according to actual conditions, and the preset time can be obtained according to actual vehicle calibration.

[0089] In some exemplary embodiments, the PWM torque control method further includes the following steps:

[0090] Step S600: performing frequency jitter processing on the frequency of the PWM torque.

[0091] Since the main reason for the noise generated by PWM torque is that the vibration frequency is relatively fixed and concentrated, the frequency of PWM torque can be made no longer fixed by performing frequency jitter processing on the frequency of PWM torque according to the current action cycle number of PWM torque (i.e. the current action cycle sequence number of PWM torque) (please continue to refer to Figure 6 , which is a schematic diagram of PWM torque frequency jittering provided by a specific example of the present invention), so that the vibration frequency is dispersed within a certain range, the vibration energy is no longer concentrated, and the noise of the corresponding frequency is also dispersed and weakened, thereby solving the noise problem caused by the fixed frequency of the PWM torque.

[0092] In some exemplary implementations, the step S600 of performing frequency jitter processing on the frequency of the PWM torque includes:

[0093] Step S610, determining the frequency jittering coefficient according to the current number of action cycles of the PWM torque and the mapping relationship between the number of action cycles of the PWM torque and the frequency jittering coefficient acquired in advance;

[0094] Step S620: Determine the frequency of the next action cycle of the PWM torque according to the initial frequency of the PWM torque strategy and the frequency jittering coefficient.

[0095] Specifically, a frequency jittering sequence with a value range of -N to N (N>0) can be designed (the frequency jittering sequence is used to characterize the mapping relationship between the number of PWM torque action cycles and the frequency jittering coefficient), and the frequency jittering coefficient corresponding to the number of PWM torque action cycles (action cycle sequence number) is found in the random frequency jittering sequence according to the number of PWM torque action cycles (action cycle sequence number).

[0096] Furthermore, the frequency fpwm of the next action cycle of the PWM torque can be determined according to the following formula:

[0097] fpwm=f*(1+facspr)

[0098] Among them, f is the initial frequency and facspr is the frequency jitter coefficient.

[0099] It should be noted that, as can be understood by those skilled in the art, the present invention does not limit the amplitude (ie, the value of N) and waveform of the frequency jittering sequence, and the frequency jittering sequence may be, but is not limited to, a random sequence (eg Figure 7 As shown), triangle wave sequence, sine wave sequence and other sequences.

[0100] In some exemplary embodiments, the frequency of the PWM torque after the frequency jittering process is greater than 2 times the natural frequency of the vehicle. Therefore, by setting the adjusted (after the frequency jittering process) frequency of the PWM torque to be greater than 2 times the natural frequency of the vehicle, the PWM torque can be adjusted at least twice within a speed fluctuation cycle to achieve the speed fluctuation suppression effect. Taking the speed fluctuation as an ideal sine wave as an example, adjusting twice is equivalent to superimposing a square wave with the same frequency in the opposite direction on the sine wave, and the main component of the square wave after Fourier decomposition is the sine wave with the same frequency.

[0101] Combine the following Figure 8 , the overall process of the PWM torque control method provided by the present invention is briefly described.

[0102] Please refer to Figure 8 , which is a schematic diagram of the overall flow of the PWM torque control method provided by one embodiment of the present invention. Figure 8As shown, under the action of PWM torque, the motor controller collects the original speed signal nem of the motor at a sampling frequency of more than 100Hz. The low-frequency speed signal nem_low of the motor is obtained by low-pass filtering the original speed signal nem of the motor. The vehicle-specific frequency speed fluctuation signal nem_low_hi of the motor is obtained by high-pass filtering the low-frequency speed signal nem_low of the motor. The torque coefficient factq is obtained by looking up the table according to the original speed signal nem of the motor and the PWM torque frequency f. The vehicle-specific frequency speed fluctuation signal nem_low_hi is inverted and multiplied by the torque coefficient factq to obtain the compensation torque tq. The compensation torque tq is output after passing through the preset upper limit torque and the preset lower limit torque limit, and the suppression torque is superimposed on the vehicle demand torque tqdes_vcu as the input torque tqdes_em of the PWM torque strategy. Further, the initial frequency f of the PWM torque strategy is obtained, and then the frequency jitter coefficient facspr is obtained by looking up the table according to the number of action cycles of the PWM torque (action cycle sequence number). Multiply the initial frequency f by (1+facspr) to get the PWM torque action frequency fpwm after adding frequency jitter. fpwm should be limited to more than 2 times the natural frequency of the vehicle. To further improve drivability, set the speed fluctuation threshold nemthd. When nem_low_hi>nemthd, immediately turn off the PWM torque strategy, and after a delay, determine whether to reopen the PWM torque strategy based on the existing conditions.

[0103] Based on the same inventive concept, the present invention also provides a motor controller, please refer to Fig. 9 , which is a schematic diagram of the block structure of a motor controller provided by one embodiment of the present invention. Fig. 9 As shown, the motor controller includes a processor 101 and a memory 103, and a computer program is stored in the memory 103. When the computer program is executed by the processor 101, the PWM torque control method described above is implemented. Since the motor controller provided by the present invention and the PWM torque control method provided by the present invention belong to the same inventive concept, the motor controller provided by the present invention at least has all the beneficial effects of the PWM torque control method provided by the present invention. For details, please refer to the relevant descriptions above, so the beneficial effects of the motor controller provided by the present invention will not be repeated here.

[0104] like Fig. 9As shown, the motor controller also includes a communication interface 102 and a communication bus 104, wherein the processor 101, the communication interface 102, and the memory 103 communicate with each other through the communication bus 104. The communication bus 104 includes but is not limited to a CAN bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus. The communication interface 102 is used for communication between the motor controller and other vehicle controllers (such as a vehicle controller, a motor controller, etc., not shown in the figure). The communication bus 104 connects the above-mentioned motor controller and other vehicle controllers (such as a vehicle controller, a motor controller, etc., not shown in the figure) and other dispersed nodes into a closed-loop system, so that each controller can perform multiple working states (parking state, charging state, starting state, running state, vehicle forward and backward state, feedback braking state, mechanical braking state, general fault state, major fault state) Communication and data transmission, thereby realizing the control function of the vehicle.

[0105] It should be noted that the processor 101 referred to in the present invention may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor 101 is the control center of the motor controller, and various interfaces and lines are used to connect various parts of the entire motor controller.

[0106] It should also be noted that the memory 103 can be used to store the computer program, and the processor 101 implements various functions of the motor controller by running or executing the computer program stored in the memory 103 and calling the data stored in the memory 103. The memory 103 may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable memory (PROM), electrically programmable memory (EPROM), electrically erasable programmable memory (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, random access memory is available in a variety of forms, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous random access memory (SDRAM), double data rate synchronous random access memory (DDRSDRAM), enhanced synchronous random access memory (ESDRAM), synchronous link (Synchlink) dynamic random access memory (SLDRAM), memory bus (Rambus) direct random access memory (RDRAM), direct memory bus dynamic random access memory (DRDRAM), and memory bus dynamic random access memory (RDRAM), etc.

[0107] The present invention also provides a readable storage medium, wherein a computer program is stored in the readable storage medium, and when the computer program is executed by a processor, the PWM torque control method described above can be implemented. Since the readable storage medium provided by the present invention and the PWM torque control method provided by the present invention belong to the same inventive concept, the readable storage medium provided by the present invention at least has all the beneficial effects of the PWM torque control method provided by the present invention, and the specifics can be referred to the relevant descriptions above, so the beneficial effects of the readable storage medium provided by the present invention will not be described one by one here.

[0108] It should be noted that the readable storage medium provided by the present invention can adopt any combination of one or more computer-readable media. The readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, a system, device or component of electricity, magnetism, light, electromagnetic, infrared or semiconductor, or any combination of the above. More specific examples (non-exhaustive enumeration) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer hard disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this article, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, a device or a device or used in combination with it.

[0109] It should also be noted that a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0110] In summary, compared with the prior art, the PWM torque control method, motor controller and readable storage medium provided by the present invention have the following beneficial effects:

[0111] The present invention first obtains the original speed information of the motor under the action of PWM torque; then filters the original speed information of the motor to obtain the speed fluctuation information of the natural frequency of the whole vehicle; then determines the suppression torque according to the speed fluctuation information of the natural frequency of the whole vehicle; finally, the superposition result of the suppression torque and the required torque of the whole vehicle is used as the target input torque of the PWM torque strategy. It can be seen that the present invention can filter out the high-frequency speed fluctuation caused by PWM torque, and only retain the speed fluctuation near the natural frequency of the whole vehicle (the speed fluctuation of the natural frequency of the whole vehicle). By applying a suppression torque that is proportional to and opposite to the speed fluctuation near the fixed frequency of the whole vehicle for control, the whole vehicle can effectively reduce the fluctuation amplitude of the whole vehicle when the PWM torque function is turned on to improve the efficiency of the electric drive system, thereby effectively improving the drivability of the whole vehicle.

[0112] In addition, the present invention can make the frequency of the PWM torque no longer fixed by performing frequency jitter processing on the frequency of the PWM torque, so that the vibration frequency is dispersed within a certain range, the vibration energy is no longer concentrated, and the noise of the corresponding frequency can also be dispersed and weakened, thereby solving the noise problem caused by the fixed frequency of the PWM torque.

[0113] It should be noted that the computer program code for performing the operation of the present invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages-such as Java, Smalltalk, C++, and also conventional procedural programming languages-such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network-including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0114] It should be noted that the devices and methods disclosed in the embodiments of this article can also be implemented in other ways. The device implementation described above is only schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of this article. In this regard, each box in the flowchart or block diagram can represent a part of a module, program or code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical function, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented by a dedicated hardware-based system for performing a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions. In addition, the functional modules in the various embodiments of this document may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0115] It should also be noted that the above description is only a description of the preferred embodiment of the present invention, and is not any limitation on the scope of the present invention. Any changes and modifications made by a person skilled in the art in the field of the present invention based on the above disclosure are within the scope of protection of the present invention. Obviously, a person skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations fall within the scope of the present invention and its equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A PWM torque control method, characterized in that: include: Get the original speed information of the motor under the action of PWM torque; Filtering the original speed information of the motor to obtain the natural frequency speed fluctuation information of the whole vehicle; Determining the suppression torque according to the natural frequency speed fluctuation information of the whole vehicle; The superposition result of the suppression torque and the vehicle demand torque is used as the target input torque of the PWM torque strategy.

2. The PWM torque control method according to claim 1, characterized in that: The filtering process of the original motor speed information to obtain the natural frequency speed fluctuation information of the whole vehicle includes: A low-pass filter is used to perform low-pass filtering on the original speed information of the motor to obtain low-frequency speed information of the motor, wherein the cut-off frequency of the low-pass filter is less than the minimum value of the PWM torque frequency and greater than the maximum value of the natural frequency of the whole vehicle; A high-pass filter is used to perform high-pass filtering on the low-frequency speed information of the motor to obtain the speed fluctuation information of the natural frequency of the whole vehicle, wherein the cut-off frequency of the high-pass filter is less than the minimum value of the natural frequency of the whole vehicle.

3. The PWM torque control method according to claim 2, characterized in that: The method further comprises: A phase corrector is used to perform phase correction on the low-frequency speed information of the motor or the natural frequency speed fluctuation information of the whole vehicle.

4. The PWM torque control method according to claim 1, characterized in that: The step of determining the suppression torque according to the natural frequency speed fluctuation information of the whole vehicle includes: Determine the torque coefficient according to the original motor speed information, the PWM torque frequency information, and the mapping relationship between the motor speed, the PWM torque frequency, and the torque coefficient acquired in advance; The suppression torque is determined according to the vehicle natural frequency speed fluctuation information and the torque coefficient.

5. The PWM torque control method according to claim 4, characterized in that: The step of determining the suppression torque according to the vehicle natural frequency speed fluctuation information and the torque coefficient includes: Inverting the natural frequency speed fluctuation information of the whole vehicle; Determining the compensation torque according to the inverted natural frequency speed fluctuation information of the whole vehicle and the torque coefficient; The compensation torque is limited according to a preset upper limit torque and a preset lower limit torque to obtain a restraining torque.

6. The PWM torque control method according to claim 1, characterized in that: The method further comprises: When the absolute value of the vehicle's natural frequency speed fluctuation value is greater than the preset speed fluctuation threshold, the PWM torque strategy is turned off, and after a preset delay time, it is determined whether the PWM torque strategy needs to be turned on.

7. The PWM torque control method according to claim 1, characterized in that: The method further comprises: Perform frequency jitter processing on the frequency of PWM torque.

8. The PWM torque control method according to claim 7, characterized in that: The frequency jittering process of the PWM torque frequency includes: Determine the frequency jitter coefficient according to the current number of action cycles of the PWM torque and the mapping relationship between the number of action cycles of the PWM torque acquired in advance and the frequency jitter coefficient; The frequency of the next action cycle of the PWM torque is determined according to the initial frequency of the PWM torque strategy and the frequency jitter coefficient.

9. The PWM torque control method according to claim 1, characterized in that: The frequency of the PWM torque after frequency jittering is greater than twice the natural frequency of the vehicle.

10. A motor controller, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the PWM torque control method according to any one of claims 1 to 9 is implemented.

11. A readable storage medium, characterized in that: The readable storage medium stores a computer program, and when the computer program is executed by a processor, the PWM torque control method according to any one of claims 1 to 9 is implemented.

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