Study On The Speed Expansion Characteristics Of Permanent Magnet Assisted Synchronous Reluctance Motor For Renewable Energy Vehicles

With the soaring prices of rare earth permanent magnet materials,permanent magnet assisted synchronous reluctance motors,with their wide weak magnetic range,high power density and excellent price advantage,have become one of the main choices for drive motors in the new energy vehicle sector and have gained unprecedented momentum.This paper examines this,the research is objective to improve the output torque of the motor at starting and solve the power limitation of the inverter when the motor is in the high-speed domain,and the main work is as follows:First of all,Derivation of the electromagnetic equations,voltage equations and equations of motion for PMASyn RM,presentation of the rotational mathematical model of the motor in Matlab/Simulink and calibration against the motor parameters to provide control objects for subsequent research.Second,the operating area of the motor is classified by speed,and for the constant torque interval,this paper deduces the MTPA control of the permanent magnet assisted synchronous reluctance motor by using the Lagrange method,solves the relative change relationship between i_d and i_q,deduces the initial parameters of the control PI,that is,K_p and K_i,and compares the MTPA control with i_d=0 control under the same condition.Then,for the constant power range,this paper analyzes the magnetic field weakening control,and directly calculates the I of magnetic field weakening control i_d and i_q variation process is deduced,the directly calculated flux weakening control is then applied to a permanent magnet assisted synchronous reluctance motor.Under the same conditions,it is compared with the flux weakening control of variable quadrature axis voltage single current regulator.Finally,the effects of the above two different control methods in different sections are optimized,and a motor full speed domain speed regulation system based on the combination of permanent magnet assisted synchronous reluctance motor MTPA control and flux weakening control is proposed.The model is built in Matlab/Simulink.In order to realize the speed zoning control of the motor,the simulation of the weak magnetic region determination by comparing the stator voltage with the limit voltage value of the inverter shows that the motor speed control system proposed in this paper requires less stator current for the same torque output and can be adjusted into a new steady state quickly when a sudden load is added.This control method provides a certain reference for the speed regulation control of Renewable Energy Vehicles.