Maximum Torque Per Ampere Control Of Permanent Magnet Synchronous Motor Under Position Sensorless Mode

Permanent magnet synchronous motors are widely used in elevators,aerospace and electric vehicles due to their high efficiency,high power density and wide speed range.In the permanent magnet synchronous motor vector control system,position sensorless control can eliminate the mechanical position sensor and improve the motor running reliability.Maximum torque per ampere control can minimize the copper loss of the motor and improve the operating efficiency of the motor.The existing high frequency signal injection method can only achieve the problem of maximum torque per ampere control or position sensorless control.This paper carries out a strategy study to achieve both position sensorless control and maximum torque per ampere control.Based on the principle of high frequency signal injection method,this paper studies the form of injection high frequency signal,injection mode,rotor position signal and maximum per ampere control point extraction method.A special high frequency signal is designed,which contains two kinds of high frequency components – high frequency pulse signal and high frequency rotation signal.The high frequency pulse signal is used to achieve the maximum torque per ampere control point extraction.The rotating high frequency signal is used to estimate the rotor position information.The high frequency signal injection method based on motor current response and the method of extracting the maximum torque per ampere control point and position information are studied.The center frequency and damping coefficient of the bandpass filter used for signal extraction are analyzed,and the parameter design method of the filter is obtained.A maximum torque per ampere control strategy of permanent magnet synchronous motor under position sensorless mode is formed.In this paper,a 20 k W permanent magnet synchronous motor experimental system is built,and the proposed control strategy is studied experimentally.The results show that the proposed control strategy can accurately obtain the maximum torque per ampere control point information,effectively estimate the rotor position of the motor,and achieve good dynamic and steady-state operation of the motor system.