An adaptive method for stabilization and prevention of dynamic voltage saturation based on MTPA / MTPV lookup table

Abstract

This invention discloses a method for stabilization and dynamic voltage saturation prevention based on MTPA / MTPV lookup table, comprising the following steps: Step 1: Filtering out loop disturbances using a conventional low-pass filter, determining the speed fluctuation period based on the actual vehicle vibration, and simultaneously determining the cutoff frequency of the low-pass filter; Step 2: Calculating the system delay time t using the cutoff frequency of the filter in Step 1, and calculating the system acceleration; Step 3: Obtaining the delay compensation speed Vc of the system to be compensated using the delay time t and acceleration a from Step 2; Step 4: Adding the delay compensation speed Vc from Step 3 to the speed Vf output by the low-pass filter to obtain the final lookup table speed V; This invention stabilizes the lookup table and compensates for the delay caused by the filter in dynamic operating conditions, avoiding voltage saturation.

Description

Technical Field

[0001] This invention relates to the field of motor equipment technology, and specifically to a method for stabilization based on MTPA / MTPV lookup table and for preventing dynamic voltage saturation adaptively. Background Technology

[0002] In passenger vehicle applications, vehicle vibrations can occur during operation due to road bumps or mechanical resonance, leading to fluctuations in the drive motor speed. Since the control command signal is determined by both torque request and actual speed, speed fluctuations trigger control command fluctuations, resulting in continuous reciprocating vibrations. Many solutions exist to address this vibration, including active damping and related signal filtering. However, each solution has its advantages and disadvantages, and presents its own challenges. For example, current technology uses a low-pass filter to remove the periodic vibration component from the actual speed. The filtered speed is then used for MTPA / MTPV software lookup. The drawback of this existing technology is that filtering external signals causes phase delays in dynamic operating conditions, resulting in the filtered speed used for lookup changing slower than the actual speed. Furthermore, the command current operating point obtained from the lookup does not match the actual motor operating state, posing a risk of dynamic voltage saturation.

[0003] Therefore, providing a method for MTPA / MTPV lookup table stabilization and dynamic voltage saturation adaptation that calculates the delayed rotational speed based on the calculated filter delay time and real-time acceleration, and compensates for the lookup table rotational speed, is a problem worthy of research. Summary of the Invention

[0004] The purpose of this invention is to provide a method for stabilizing and preventing dynamic voltage saturation of the MTPA / MTPV lookup table based on the calculated filter delay time and the real-time acceleration, thereby calculating the delayed rotational speed and compensating for the lookup table rotational speed.

[0005] The objective of this invention is achieved as follows:

[0006] A method for stabilization and dynamic voltage saturation prevention based on MTPA / MTPV lookup table includes the following steps:

[0007] Step 1: Filter out loop disturbances using a conventional low-pass filter. Based on the actual vehicle vibration, the speed fluctuation period can be determined using the speed information received from the host computer. Combining calibration experience with the actual filtering effect on site, the cutoff frequency f of the low-pass filter can be determined. The purpose of this step is to filter out the speed vibration signal using a suitable low-pass filter, and then use the filtered speed for subsequent MTPA / MTPV lookup table to eliminate or reduce the fluctuation of the lookup results caused by speed vibration.

[0008] Step 2: Using the cutoff frequency f of the filter in Step 1 and the characteristics of the first-order low-pass filter, calculate the system delay time t = 4 / (2*π*f). At the same time, calculate the system acceleration a based on the velocity derivative after filtering, as the basis for implementing Step 3.

[0009] Step 3: Using the delay time t and acceleration a from Step 2, obtain the delay compensation speed Vc of the system that needs compensation, as the basis for implementing Step 4;

[0010] Step 4: Add the delay-compensated speed Vc from Step 3 to the speed Vf output by the low-pass filter to obtain the final lookup speed V; that is, obtain the lookup speed that both filters out loop noise and compensates for loop delay.

[0011] In step 2, the acceleration a = dVf / dt is calculated using the velocity Vf output by the low-pass filter.

[0012] In step 3, the formula for calculating the delay compensation speed Vc is as follows: Vc = a * t.

[0013] In step 4, the final lookup speed V = Vf + Vc is obtained, which is used for MTPA / MTPV lookup.

[0014] Positive and beneficial effects: This invention filters out periodic fluctuations in rotational speed using a low-pass filter, stabilizing the lookup table effect; and by calculating the filter delay time and real-time acceleration, the delayed rotational speed can be calculated and compensated for. This compensates for the delay caused by the filter in dynamic operating conditions and avoids voltage saturation. Attached Figure Description

[0015] Figure 1 This is a flowchart of the present invention. Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] A method for stabilization and dynamic voltage saturation prevention based on MTPA / MTPV lookup table includes the following steps: Figure 1 As shown, Figure 1 The part in the dashed line represents the algorithm process of this invention;

[0018] Step 1: Filter out loop disturbances using a conventional low-pass filter. Based on the actual vehicle vibration, the speed fluctuation period can be determined using the speed information received from the host computer. Combining calibration experience with the actual filtering effect on site, the cutoff frequency f of the low-pass filter can be determined. The purpose of this step is to filter out the speed fluctuation signal using a suitable low-pass filter, and then use the filtered speed for subsequent MTPA / MTPV lookup table to eliminate or reduce the fluctuation of the lookup results caused by speed fluctuation.

[0019] Step 2: Using the cutoff frequency f of the filter in Step 1 and the characteristics of the first-order low-pass filter, calculate the system delay time t = 4 / (2*π*f). At the same time, calculate the system acceleration a based on the differential of the filtered velocity, as the basis for implementing Step 3. Calculate the acceleration a = dVf / dt using the velocity Vf output by the low-pass filter.

[0020] Step 3: Using the delay time t and acceleration a from Step 2, obtain the delay compensation speed Vc of the system that needs compensation, as the basis for implementing Step 4; the calculation formula for delay compensation speed Vc is as follows: Vc=a*t; the final lookup speed V =Vf + Vc is obtained, which is used for MTPA / MTPV lookup.

[0021] Step 4: Add the delay-compensated speed Vc from Step 3 to the speed Vf output by the low-pass filter to obtain the final lookup speed V; that is, the lookup speed that both filters out loop noise and compensates for loop delay is obtained; this compensates for the delay in dynamic operating conditions caused by the filter and avoids voltage saturation.

[0022] This invention uses a low-pass filter to remove periodic fluctuations in rotational speed, stabilizing the lookup table effect. Furthermore, by calculating the filter delay time and using real-time acceleration, the delayed rotational speed can be calculated and compensated for. This compensates for the delay introduced by the filter in dynamic operating conditions, preventing voltage saturation.

Claims

1. A method for stabilization and dynamic voltage saturation prevention based on MTPA / MTPV lookup table, characterized in that: The process includes the following steps: Step 1: Filter out loop disturbances using a conventional low-pass filter. Based on the actual vehicle vibration, the speed fluctuation period can be determined using the speed information received from the host computer. Combining calibration experience and the actual filtering effect on-site, the cutoff frequency f of the low-pass filter can be determined. The purpose of this step is to filter out the speed fluctuation signal using a suitable low-pass filter and use the filtered speed for subsequent MTPA / MTPV lookup table calculations to eliminate or reduce the fluctuations in the lookup results caused by speed fluctuations. Step 2: Using the cutoff frequency f of the filter in Step 1 and the characteristics of a first-order low-pass filter, calculate the system delay time t = 4 / (2*π*f). Simultaneously, calculate the system acceleration a based on the differential of the filtered speed, as the basis for Step 3. Step 3: Using the delay time t and acceleration a from Step 2, obtain the system delay compensation speed Vc, as the basis for Step 4. Step 4: Add the delay-compensated speed Vc from Step 3 to the speed Vf output by the low-pass filter to obtain the final lookup speed V; that is, obtain the lookup speed that both filters out loop noise and compensates for loop delay. In step 2, the acceleration a = dVf / dt is calculated using the velocity Vf output by the low-pass filter. In step 3, the formula for calculating the delay compensation speed Vc is as follows: Vc = a * t; In step 4, the final lookup speed V = Vf + Vc is obtained, which is used for MTPA / MTPV lookup.

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