Pwm torque control method, motor controller, and readable storage medium

Abstract

The application provides a PWM torque control method, a motor controller and a readable storage medium, and the method comprises the following steps: obtaining motor original rotating speed information under the action of a PWM torque; performing filtering processing on the motor original rotating speed information to obtain vehicle inherent frequency rotating speed fluctuation information; determining a suppression torque according to the vehicle inherent frequency rotating speed fluctuation information; and taking the superposition result of the suppression torque and a vehicle demand torque as a target input torque of a PWM torque strategy. The application can effectively reduce the fluctuation amplitude of the vehicle in the case that the PWM torque function is started to improve the efficiency of the electric drive system, and thus the driving performance of the vehicle can be effectively improved.

Description

Technical Field

[0001] This 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 Technology

[0002] When the commanded torque of the vehicle is lower than the optimal torque for the electric drive system, the commanded torque can be equivalent to a PWM torque output with a certain duty cycle through torque-time equivalent pulse width modulation. Here, a high level represents the positive optimal torque for the electric drive, and a low level represents the electric drive being off or the negative optimal 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 but discontinuous, which can easily cause the vehicle to vibrate around its natural frequency, affecting the driving experience.

[0004] Please refer to Figure 1 This is a schematic diagram illustrating the speed fluctuation under the action of PWM torque. For example... Figure 1 As shown, under the action of PWM torque, there are generally two frequencies of speed fluctuations in electric drives or wheel ends: one is the speed fluctuation caused by the PWM torque itself, with a frequency of about 20Hz to 60Hz. This fluctuation has a relatively small amplitude and a high frequency, and is basically imperceptible after being filtered by the vehicle's 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 larger, generally more than 2 to 3 times that of the speed fluctuation caused by the PWM torque itself, and the frequency is lower, generally about 6Hz to 12Hz, which is easily perceived.

[0005] 2. PWM torque frequency is relatively high, generally around 20Hz to 60Hz. Using a fixed frequency under certain operating conditions can easily cause the electric drive system to vibrate and radiate noise of the same frequency, affecting the driving experience.

[0006] It should be noted that the information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

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

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

[0009] Obtain the original motor speed information under PWM torque;

[0010] The original motor speed information is filtered to obtain the vehicle's inherent frequency speed fluctuation information;

[0011] The suppression torque is determined based on the vehicle's inherent frequency speed fluctuation information;

[0012] The sum of the suppressed torque and the required torque of the vehicle is used as the target input torque for the PWM torque strategy.

[0013] Optionally, the step of filtering the original motor speed information to obtain the vehicle's inherent frequency speed fluctuation information includes:

[0014] The original motor speed information is processed by a low-pass filter to obtain low-frequency motor speed information. The cutoff 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.

[0015] A high-pass filter is used to process the low-frequency speed information of the motor to obtain the speed fluctuation information of the vehicle's natural frequency. The cutoff frequency of the high-pass filter is less than the minimum value of the vehicle's natural frequency.

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

[0017] A phase corrector is used to correct the low-frequency speed information of the motor or the speed fluctuation information of the vehicle's natural frequency.

[0018] Optionally, determining the suppression torque based on the vehicle's inherent frequency speed fluctuation information includes:

[0019] The torque coefficient is determined based on the original motor speed information, PWM torque frequency information, and the pre-acquired mapping relationship between motor speed, PWM torque frequency, and torque coefficient.

[0020] The suppression torque is determined based on the vehicle's inherent frequency speed fluctuation information and the torque coefficient.

[0021] Optionally, determining the suppression torque based on the vehicle's inherent frequency speed fluctuation information and the torque coefficient includes:

[0022] The inherent frequency speed fluctuation information of the vehicle is inverted;

[0023] The compensation torque is determined based on the inverted vehicle's inherent frequency speed fluctuation information and the torque coefficient.

[0024] The compensation torque is limited based on a preset upper limit torque and a preset lower limit torque to obtain a suppression torque.

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

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

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

[0028] Frequency jittering is applied to the PWM torque.

[0029] Optionally, the frequency dithering of the PWM torque includes:

[0030] The frequency dithering coefficient is determined based on the current number of PWM torque cycles and the pre-obtained mapping relationship between the number of PWM torque cycles and the frequency dithering coefficient.

[0031] The frequency of the next action cycle of the PWM torque is determined based on the initial frequency of the PWM torque strategy and the frequency dithering coefficient.

[0032] Optionally, the frequency of the PWM torque after frequency dithering is greater than twice the vehicle's natural frequency.

[0033] To achieve the above objectives, the present invention also provides a motor controller, including 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 described above is implemented.

[0034] To achieve the above objectives, the present invention also provides a readable storage medium storing a computer program, which, when executed by a processor, implements the PWM torque control method described above.

[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 advantages:

[0036] The PWM torque control method provided by this invention first obtains the original motor speed information under the action of PWM torque; then filters the original motor speed information to obtain the vehicle's natural frequency speed fluctuation information; then determines the suppression torque based on the vehicle's natural frequency speed fluctuation information; finally, the superposition result of the suppression torque and the vehicle's required torque is used as the target input torque of the PWM torque strategy. Therefore, by using the PWM torque control method provided by this invention, high-frequency speed fluctuations caused by PWM torque can be filtered out, while only speed fluctuations near the vehicle's natural frequency (vehicle natural frequency speed fluctuations) are retained. By applying a suppression torque that is proportional to and opposite to the speed fluctuations near the vehicle's fixed frequency, the vehicle's fluctuation amplitude can be effectively reduced while the PWM torque function is enabled to improve the efficiency of the electric drive system, thereby effectively improving the vehicle's drivability.

[0037] Since the motor controller and readable storage medium provided by this invention belong to the same inventive concept as the PWM torque control method provided by this invention, the motor controller and readable storage medium provided by this invention have at least all the beneficial effects of the PWM torque control method provided by this invention. For details, please refer to the relevant description above. Therefore, the beneficial effects of the motor controller and readable storage medium provided by this invention will not be elaborated here. Attached Figure Description

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

[0039] Figure 2 This is a flowchart illustrating a PWM torque control method according to an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of the original motor speed signal provided in a specific example of the present invention;

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

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

[0043] Figure 6 This is a schematic diagram of PWM torque frequency jitter provided as a specific example of the present invention;

[0044] Figure 7 This is a schematic diagram of a frequency dithering sequence provided as a specific example of the present invention;

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

[0046] Figure 9 This is a block diagram of a motor controller provided in one embodiment of the present invention. Detailed Implementation

[0047] The PWM torque control method, motor controller, and readable storage medium proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clarify the purpose provided by this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to enable those skilled in the art to understand and read them, and are not intended to limit the implementation conditions of this invention. Any modifications to the structure, changes in proportions, or adjustments to the size, provided that the effects and objectives achieved by this invention are the same or similar, should still fall within the scope of the technical content disclosed in this invention.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The singular forms “a,” “an,” and “the” include plural objects. The term “or” is generally used to mean “and / or,” the term “several” is generally used to mean “at least one,” and the term “at least two” is generally used to mean “two or more.” Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0049] Furthermore, in the description of this specification, the reference to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions 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 a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[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 range of the whole vehicle when the PWM torque function is enabled 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. The motor controller provided by the present invention can be configured on electric vehicles, including but not limited to electric vehicles such as SUVs, buses, trucks, and various commercial vehicles. The motor controller can be a hardware device with various operating systems.

[0052] To achieve the above-mentioned goals, this invention provides a PWM torque control method, please refer to [reference needed]. Figure 2 This is a flowchart illustrating a PWM torque control method provided in one embodiment of the present invention. Figure 2 As shown, the PWM torque control method includes the following steps:

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

[0054] Step S200: Filter the original motor speed information to obtain the vehicle's inherent frequency speed fluctuation information.

[0055] Step S300: Determine the suppression torque based on the vehicle's inherent frequency speed fluctuation information.

[0056] Step S400: The superposition result of the suppressed torque and the vehicle demand torque is used as the target input torque of the PWM torque strategy.

[0057] Therefore, by using the PWM torque control method provided by this invention, the high-frequency speed fluctuations caused by PWM torque can be filtered out, while only the speed fluctuations near the vehicle's natural frequency (vehicle natural frequency speed fluctuations) are retained. By applying a suppressing torque that is proportional to and opposite to the speed fluctuations near the vehicle's fixed frequency, the vehicle can effectively reduce the fluctuation amplitude while the PWM torque function is enabled to improve the efficiency of the electric drive system, thereby effectively improving the vehicle's drivability.

[0058] Specifically, when PWM torque is applied, the motor controller can acquire the original motor speed signal nem (motor speed before filtering) at a sampling frequency of 100Hz or higher. It should be noted that, as those skilled in the art will understand, the target input torque of the PWM torque strategy is equal to the sum of the suppressed torque and the required torque for the entire vehicle. It should also be noted that, as those skilled in the art will understand, the acquired original motor speed information refers to the real-time motor speed information acquired by the motor controller, and the acquired original motor speed information changes in real time.

[0059] In some exemplary embodiments, step S200, filtering the original motor speed information to obtain vehicle inherent frequency speed fluctuation information, includes:

[0060] Step S210: Use a low-pass filter to perform low-pass filtering on the original motor speed information to obtain low-frequency motor speed information. The cutoff 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 vehicle's natural frequency speed fluctuation information, wherein the cutoff frequency of the high-pass filter is less than the minimum value of the vehicle's natural frequency.

[0062] For details, please refer to Figures 3 to 5 ,in, Figure 3 This is a schematic diagram of the original motor speed signal provided in a specific example of the present invention; Figure 4 A schematic diagram of a low-pass filtered motor speed signal provided as a specific example of the present invention; Figure 5 This is a schematic diagram of a high-pass filtered motor speed signal provided as a specific example of the present invention. Figure 3 and Figure 4 As shown, by using a low-pass filter with a cutoff frequency less than the minimum value of the PWM torque frequency and greater than the maximum value of the vehicle's fixed frequency to filter the original motor speed information, high-frequency speed fluctuations caused by PWM torque can be effectively filtered out. Figure 4 and Figure 5As shown, by using a high-pass filter with a cutoff frequency lower than the minimum value of the vehicle's natural frequency to perform high-pass filtering on the low-frequency information of the motor, speed fluctuations near the vehicle's natural frequency can be effectively preserved. Furthermore, since the speed fluctuations caused by PWM torque have a higher frequency and smaller amplitude compared to speed fluctuations near the vehicle's natural frequency, and because this part of the speed fluctuation (speed fluctuations caused by PWM torque) is at the same frequency as the PWM torque and cannot be suppressed by applying reverse torque, and is essentially imperceptible after filtering 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 will understand, the present invention does not limit the specific types of the low-pass filter and the high-pass filter, and the low-pass filter and the high-pass filter can be, but are not limited to, digital filters, band-pass filters, notch filters, etc.

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

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

[0066] Correspondingly, in step S220, a high-pass filter is used to perform high-pass filtering on the low-frequency speed information of the motor to obtain the vehicle's inherent frequency speed fluctuation information. Specifically:

[0067] A high-pass filter is used to process the phase-corrected low-frequency speed information of the motor to obtain the vehicle's inherent frequency speed fluctuation information.

[0068] Therefore, by using a phase corrector to correct the phase of 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 inherent frequency speed fluctuation information and effectively preventing the speed fluctuation from worsening due to errors in the direction and magnitude of the suppressed 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, please refer to relevant content in the field of signal processing that is known to those skilled in the art, and will not be elaborated here.

[0070] In some other exemplary embodiments, before performing step S300 and determining the suppression torque based on the vehicle's inherent frequency speed fluctuation information, the PWM torque control method further includes the following steps:

[0071] Step S221: Use a phase corrector to perform phase correction on the vehicle's inherent frequency speed fluctuation information.

[0072] Correspondingly, step S300, determining the suppression torque based on the vehicle's inherent frequency speed fluctuation information, specifically involves:

[0073] Based on the vehicle's natural frequency speed fluctuation information after phase correction, the suppression torque is determined.

[0074] Therefore, by using a phase corrector to correct the phase of the vehicle's natural frequency speed fluctuation information, the phase lag and lead phenomenon caused by the delay effect of the high-pass filter can be corrected. This ensures the accuracy of the suppression torque determined based on the corrected vehicle's natural frequency speed fluctuation information and effectively prevents the speed fluctuation from worsening due to errors in the direction and magnitude of the suppression torque.

[0075] In some exemplary embodiments, step S300, determining the suppression torque based on the vehicle's inherent frequency speed fluctuation information, includes:

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

[0077] Step S320: Determine the suppression torque based on the vehicle's inherent frequency speed fluctuation information and the torque coefficient.

[0078] Specifically, the mapping relationship between motor speed, PWM torque frequency, and torque coefficient can be recorded in a torque coefficient table. The torque coefficient corresponding to the original motor speed and current PWM torque frequency can be obtained by looking up the value in the table. It should be noted that, as those skilled in the art will understand, the mapping relationship between motor speed, PWM torque frequency, and torque coefficient can be obtained through actual vehicle calibration.

[0079] In some exemplary embodiments, step S320, determining the suppression torque based on the vehicle's inherent frequency speed fluctuation information and the torque coefficient, includes:

[0080] Step S321: Invert the vehicle's inherent frequency speed fluctuation information.

[0081] Step S322: Determine the compensation torque based on the inverted vehicle's inherent frequency speed fluctuation information and the torque coefficient.

[0082] Step S323: Limit 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 inverted result of the vehicle's natural frequency speed fluctuation value by the determined torque coefficient. By setting upper and lower limits on the compensation torque according to preset upper and lower torque limits, it can be ensured that the obtained suppression torque is greater than or equal to the preset lower torque limit and less than or equal to the preset upper torque limit. It should be noted that, as those skilled in the art will understand, when the calculated compensation torque is less than the preset lower torque limit, the preset lower torque limit is used as the suppression torque; when the calculated compensation torque is greater than or equal to the preset lower torque limit and less than or equal to the preset upper torque limit, the compensation torque is used as the suppression torque; when the calculated compensation torque is greater than the preset upper torque limit, the preset upper torque limit is used as the suppression torque. It should be noted that, as those skilled in the art will understand, the specific values ​​of the preset upper torque limit and the preset lower torque limit can be set according to actual conditions, and this invention does not limit the specific values ​​of the preset upper torque limit and the preset lower torque limit.

[0084] It should also be noted that, as those skilled in the art will understand, in some other embodiments, closed-loop control can also be performed based on the vehicle's inherent frequency speed fluctuation information to determine the suppression torque. Specifically, regarding how to perform closed-loop control based on the vehicle's inherent frequency speed fluctuation information to determine the suppression torque, please refer to the relevant content in the field of PID controller technology, which is well known to those skilled in the art, and 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 inherent frequency speed fluctuation value is greater than the preset speed fluctuation threshold, the PWM torque strategy is turned off, and after a preset delay, it is determined whether the PWM torque strategy needs to be turned on again.

[0087] Therefore, by disabling 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 then determining whether the PWM torque strategy needs to be enabled after a preset delay, the problem of insignificant speed fluctuation suppression effect and large vehicle vibration caused by bumpy roads or rapid acceleration and deceleration 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 those skilled in the art will understand, after a preset delay, if the absolute value of the vehicle's inherent frequency speed fluctuation is less than or equal to the preset speed fluctuation threshold, the PWM torque strategy will be restarted. It should also be noted that, as those skilled in the art will understand, this invention does not limit the specific values ​​of the preset speed fluctuation threshold and the preset delay. The specific value of the preset speed fluctuation threshold can be set according to actual conditions, and the preset delay can be obtained from actual vehicle calibration.

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

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

[0091] Since the main reason for noise generation in PWM torque is the relatively fixed and concentrated vibration frequency, frequency dithering of the PWM torque can be performed based on the current cycle number (i.e., the current cycle number) to make the PWM torque frequency less fixed (please refer to [reference]). Figure 6 (This is a schematic diagram of PWM torque frequency jitter provided in a specific example of the present invention), thereby causing the vibration frequency to be dispersed within a certain range, so that 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 PWM torque.

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

[0093] Step S610: Determine the frequency dithering coefficient based on the current number of PWM torque cycles and the pre-obtained mapping relationship between the number of PWM torque cycles and the frequency dithering coefficient.

[0094] Step S620: Determine the frequency of the next action cycle of the PWM torque based on the initial frequency of the PWM torque strategy and the frequency dithering coefficient.

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

[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] Where f is the initial frequency and facspr is the frequency dithering coefficient.

[0099] It should be noted that, as those skilled in the art will understand, the present invention does not limit the amplitude (i.e., the value of N) and waveform of the frequency dithering sequence, and the frequency dithering sequence can be, but is not limited to, a random sequence (e.g., Figure 7 (As shown), triangular wave sequence, sine wave sequence, and other sequences.

[0100] In some exemplary implementations, the frequency of the PWM torque after frequency dithering is greater than twice the vehicle's natural frequency. Therefore, by setting the adjusted (dithered) frequency of the PWM torque to be greater than twice the vehicle's natural frequency, at least two adjustments to the PWM torque are required within one speed fluctuation cycle to achieve speed fluctuation suppression. Taking the speed fluctuation as an ideal sine wave as an example, two adjustments are equivalent to superimposing a square wave of the same frequency in the opposite direction onto the sine wave, and the main component after Fourier decomposition of the square wave is the same-frequency sine wave.

[0101] The following is combined Figure 8 The overall process of the PWM torque control method provided by the present invention will be briefly described.

[0102] Please refer to Figure 8 This is a schematic diagram of the overall flow of a PWM torque control method provided in one embodiment of the present invention. Figure 8As shown, under the action of PWM torque, the motor controller acquires the original motor speed signal nem at a sampling frequency of over 100Hz. The original motor speed signal nem is low-pass filtered to obtain the low-frequency motor speed signal nem_low. The low-frequency motor speed signal nem_low is high-pass filtered to obtain the vehicle's natural frequency speed fluctuation signal nem_low_hi. The torque coefficient factq is obtained by looking up a table based on the original motor speed signal nem and the PWM torque frequency f. The vehicle's natural 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 passed through preset upper and lower torque limits to output the suppression torque. The suppression torque is superimposed on the vehicle's required torque tqdes_vcu and used as the input torque tqdes_em for the PWM torque strategy. Further, the initial frequency f of the PWM torque strategy is obtained, and then the frequency dithering coefficient facspr is obtained by looking up a table based on the number of PWM torque cycles (cycle sequence number). Multiplying the initial frequency f by (1+facspr) yields the effective frequency fpwm of the PWM torque after adding frequency dithering. fpwm should be limited to more than twice the vehicle's natural frequency. To further improve drivability, a speed fluctuation threshold nemthd is set. When nem_low_hi > nemthd, the PWM torque strategy is immediately disabled, and after a delay, a decision is made based on the existing conditions whether the PWM torque strategy needs to be re-enabled.

[0103] Based on the same inventive concept, this invention also provides a motor controller, please refer to... Figure 9 This is a block diagram of a motor controller provided in one embodiment of the present invention. Figure 9 As shown, the motor controller includes a processor 101 and a memory 103. The memory 103 stores a computer program. When the computer program is executed by the processor 101, it implements the PWM torque control method described above. Since the motor controller provided by this invention and the PWM torque control method provided by this invention belong to the same inventive concept, the motor controller provided by this invention has at least all the beneficial effects of the PWM torque control method provided by this invention. For details, please refer to the relevant descriptions above. Therefore, the beneficial effects of the motor controller provided by this invention will not be elaborated here.

[0104] like Figure 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. For ease of illustration, only one thick line is used to represent it in the figure, but this does not mean that there is only one bus or one type of bus. The communication interface 102 is used for communication between the above-mentioned motor controller and other vehicle controllers (such as the vehicle controller, motor controller, etc., not shown in the figure). The communication bus 104 connects the above-mentioned motor controller and other vehicle controllers (such as the vehicle controller, motor controller, etc., not shown in the figure) into a closed-loop system, enabling each controller to perform communication and data transmission in multiple working states (parking state, charging state, starting state, running state, vehicle forward and reverse state, regenerative braking state, mechanical braking state, general fault state, major fault state), thereby realizing the vehicle control function.

[0105] It should be noted that the processor 101 referred to in this invention can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. The processor 101 is the control center of the motor controller, connecting various parts of the entire motor controller via various interfaces and lines.

[0106] It should also be noted that the memory 103 can be used to store the computer program. 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), dual data rate synchronous random access memory (DDRSDRAM), enhanced synchronous random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), memory bus direct random access memory (RDRAM), direct memory bus dynamic random access memory (DRDRAM), and memory bus dynamic random access memory (RDRAM), etc.

[0107] This invention also provides a readable storage medium storing a computer program that, when executed by a processor, can implement the PWM torque control method described above. Since the readable storage medium and the PWM torque control method provided by this invention belong to the same inventive concept, the readable storage medium provided by this invention possesses at least all the beneficial effects of the PWM torque control method provided by this invention. For details, please refer to the relevant descriptions above; therefore, the beneficial effects of the readable storage medium provided by this invention will not be elaborated upon here.

[0108] It should be noted that the readable storage medium provided by this invention can be 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. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples (not exhaustive) of computer-readable storage media include: electrical connections having one or more wires, portable computer hard disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, apparatus, or device.

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

[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] This invention first acquires the original motor speed information under PWM torque; then filters the original motor speed information to obtain the vehicle's inherent frequency speed fluctuation information; then determines the suppression torque based on the vehicle's inherent frequency speed fluctuation information; finally, the superposition result of the suppression torque and the vehicle's required torque is used as the target input torque of the PWM torque strategy. Thus, this invention can filter out high-frequency speed fluctuations caused by PWM torque, retaining only speed fluctuations near the vehicle's inherent frequency (vehicle inherent frequency speed fluctuation). By applying a suppression torque proportional to and opposite to the speed fluctuations near the vehicle's fixed frequency, the vehicle can effectively reduce the overall fluctuation amplitude while the PWM torque function is enabled to improve the efficiency of the electric drive system, thereby effectively improving the vehicle's drivability.

[0112] Furthermore, by performing frequency dithering on the PWM torque, the frequency of the PWM torque is no longer fixed, thereby dispersing the vibration frequency within a certain range and preventing the vibration energy from concentrating. Consequently, the noise at the corresponding frequency is also dispersed and reduced, thus solving the noise problem caused by the fixed frequency of the PWM torque.

[0113] It should be noted that computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof. These programming languages ​​include object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0114] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions. In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0115] It should also be noted that the above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure are within the protection scope of the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the present invention and its equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A PWM torque control method, characterized in that, include: Obtain the original motor speed information under PWM torque; The original motor speed information is filtered to obtain the vehicle's inherent frequency speed fluctuation information; The suppression torque is determined based on the vehicle's inherent frequency speed fluctuation information; The sum of the suppressed torque and the required torque of the whole vehicle is used as the target input torque of the PWM torque strategy; The method further includes: The frequency of the PWM torque is jittered, and the frequency of the PWM torque after jittering is greater than twice the natural frequency of the vehicle. The frequency dithering process for the PWM torque includes: The frequency dithering coefficient is determined based on the current number of PWM torque cycles and the pre-obtained mapping relationship between the number of PWM torque cycles and the frequency dithering coefficient. The frequency of the next action cycle of the PWM torque is determined based on the initial frequency of the PWM torque strategy and the frequency dithering coefficient.

2. The PWM torque control method according to claim 1, characterized in that, The step of filtering the original motor speed information to obtain the vehicle's inherent frequency speed fluctuation information includes: The original motor speed information is processed by a low-pass filter to obtain low-frequency motor speed information. The cutoff 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. A high-pass filter is used to process the low-frequency speed information of the motor to obtain the speed fluctuation information of the vehicle's natural frequency. The cutoff frequency of the high-pass filter is less than the minimum value of the vehicle's natural frequency.

3. The PWM torque control method according to claim 2, characterized in that, The method further includes: A phase corrector is used to correct the low-frequency speed information of the motor or the speed fluctuation information of the vehicle's natural frequency.

4. The PWM torque control method according to claim 1, characterized in that, The step of determining the suppression torque based on the vehicle's inherent frequency speed fluctuation information includes: The torque coefficient is determined based on the original motor speed information, PWM torque frequency information, and the pre-acquired mapping relationship between motor speed, PWM torque frequency, and torque coefficient. The suppression torque is determined based on the vehicle's inherent 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 based on the vehicle's inherent frequency speed fluctuation information and the torque coefficient includes: The inherent frequency speed fluctuation information of the vehicle is inverted; The compensation torque is determined based on the inverted vehicle's inherent frequency speed fluctuation information and the torque coefficient. The compensation torque is limited based on a preset upper limit torque and a preset lower limit torque to obtain a suppression torque.

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

7. A motor controller, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, which, when executed by the processor, implements the PWM torque control method according to any one of claims 1 to 6.

8. A readable storage medium, characterized in that, The readable storage medium stores a computer program, which, when executed by a processor, implements the PWM torque control method according to any one of claims 1 to 6.

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