Research On Flux-weakening Expansion Technology Of Vehicle Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)has the advantages of high efficiency,high power density,high torque-inertia ratio.These advantages have contributed to the rapid development of electric vehicles(EV).However,the permanent magnet has the characteristic of constant magnetic flux,The application of permanent magnet synchronous motor in high speed demand electric vehicle is seriously restricted.Generally,there are two different ways to increase the speed range: increasing the drive input voltage and flux weakening(FW).However,at present,the input voltage of a conventional motor drive is limited by the volume and weight of an electric vehicle,Under the premise that the battery capacity is certain,the weak magnetic control has become the most commonly used method of expansion.This paper starts with the mathematical principle of PMSM,building a mathematical model of dq axis coordinate system.Studying on the principle of the current and voltage limit circle of PMSM,it is found that the air gap flux can be weakened by increasing the straight shaft current.So as to realize wide speed regulation range,by comparing the maximum torque to current ratio(MTPA)control,the maximum output power control,and the stator current optimal control strategy,The advanced angle weakening control system is designed.By analyzing the application of coordinate transformation,space vector pulse width modulation(SVPWM)and PID closed loop in vector control system,the PMSM flux weakening vector control system is constructed.Using Matlab/Simulink to build a simulation model of the advanced angle weakening flux control system,simulation and analysis of SVPWM module and flux weakening control system.The effectiveness of the advanced angle weakening flux control design is verified.T M S 3 2 0 F 2 8 3 3 5 as the control core of the hardware circuit is designed,the software of the main control unit is programmed based on the C C S 3.3 development platform and a host computer platform with monitoring and debugging functions is designed by using Labview to achieve on-line linkage;setting up experimental platform of magnetic flux weakening control to complete the initial position test,SVPWM,weak magnetic control test,by mining PMSM experimental data,the feasibility of flux weakening control is verified.