Model Prediction-Direct Torque Control Method for Permanent Magnet Synchronous Motor

Abstract

A permanent magnet synchronous motor model prediction-direct torque control method belongs to the field of control technology. The purpose of the present invention is to utilize the dimension reduction observer to complete the accurate estimation of torque and flux linkage in the system, and then adopt the model predictive control algorithm to design the permanent magnet synchronous motor model prediction-direct torque control method of the hub motor drive system controller . The steps of the invention are: selecting motor torque and flux linkage as state quantities, selecting an objective function that minimizes the error between predicted value and expected value of torque and flux linkage, and obtaining three-phase voltage for controlling the motor to complete the control of PMSM. The model predictive control algorithm applied in the present invention can effectively deal with multi-input multi-output and multi-constraint optimization control problems, replaces the hysteresis comparator and switch selection module in the traditional direct torque control, and avoids the upper and lower limits of the hysteresis. Unnecessary switching loss effectively suppresses the torque ripple of the drive motor.

Description

technical field [0001] The invention belongs to the technical field of control. Background technique [0002] With the improvement of people's quality of life and the rapid development of the automobile industry, the number of automobiles in my country has continued to increase in recent years, and the global non-renewable energy reserves have been continuously consumed, which has seriously threatened energy security, especially the use of a large number of traditional fuel vehicles. deterioration of the environment. Electric vehicles have the advantages of high energy efficiency, zero emissions, and low pollution, and have become the development trend of future automobiles. [0003] The electric vehicle driven by the in-wheel motor is a research hotspot in recent years. The biggest feature of this electric vehicle is that the motor is installed on the wheel of the electric vehicle. The driving torque generated by the motor acts directly on the wheel, which saves the complic...

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Problems solved by technology

[0006] 1. The mathematical model of the hub motor is complex, and there are problems such as current coupling and large dependence on motor parameters. The transformation of the current in different coordinate systems increases the amount of calculation of the control system, slows down the dynamic response, and affects the drive of the hub motor. The control effect of the system, especially in the case of sudden traffic changes, if the drive system cannot respond in time, it is easy to cause traffic accidents

[0007] 2. There is a problem of inaccurate estimation of flux linkage. When the control system needs to directly track and control torque and flux linkage, it cannot directly obtain the actual torque and flux linkage values ​​at the current moment through measurement, while torque and flux linkage The estimated deviation of will directly affect the control effect of the in-wheel motor drive system

[0008] 3. The effective control of the three-phase inverter plays a key role in improving the control performance of the motor drive system. Due to the dead time in the actual inverter, it will cause torque and flux linkage errors and increase losses. It may even cause the system to oscillate

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