A Research Of Dynamic Maximum Torque Per Ampere Control Method Of Permanent Magnet Synchronous Motor For Electric Vehicle

With the development of electric vehicles,Permanent Magnet Synchronous Motor(PMSM)is widely used in the electric vehicle industry because of its high power density,high efficiency,and high torque.The PMSM requires large torque and high speed,so Interior Permanent Magnet Synchronous motor(IPMSM)meets the requirements.Because of the characteristics of rotor magnetic circuit asymmetry and the reluctance torque exists,the Maximum Torque per Ampere(MTPA)can be used to make full use of the reluctance torque and maximum the output torque and improve the system efficiency as much as possible.In order to control the electric vehicle PMSM to run stably in the full speed range,this paper studies the MTPA control strategy and designs a dynamic MTPA control strategy.The main contents of this paper are as follows:1.The mathematical model of PMSM,the principle of coordinate transformation and the principle of vector control are studied.The essential principle of PMSM MTPA control is studied.Combined with d-q model of PMSM,the expected function of MTPA control is derived by solving voltage equation and torque equation.2.The common MTPA control methods are studied.The principles and characteristics of each method are analyzed.In terms of the MTPA control of PMSM in electric vehicle,this paper designs a MTPA control algorithm based on linear interpolation look-up table method.3.In order to control electric vehicle PMSM stably run in whole speed range,this paper designs a control algorithm combining linear interpolation look-up method MTPA control and modulation hysteresis loop flux weakening control.The two algorithms are connected by modulation,so the purpose of stable and dynamic switching of the control algorithm is achieved when the motor speed and the torque changed at any time during the operation.Finally,the bench test is conducted to verify that the algorithm proposed and designed in this paper can make the electric vehicle PMSM stable work in the full speed range.Finally,the driving experiment on the electric vehicle shows that the algorithm can run steadily and achieve the desired goal.