Research On Field-weakening Control Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor has been widely used because of its advantages such as high efficiency,high power density,wide speed range,etc.Especially in recent years,more and more attention has been paid to the development of permanent magnetic materials.The introduction of the field-weakening control to the control strategy of the PMSM can significantly increase its speed range and broaden its application field.This paper outlines the structural features and advantages of PMSM,and then sums up the common control methods of PMSM and the development status of flux-weakening control at home and abroad.The coordinate transformation,space vector pulse width modulation(SVPWM)technology and vector control strategy commonly used in PMSM control are analyzed and introduced comprehensively,which provides the necessary theoretical basis for the study of field-weakening control of PMSM.For the study of field-weakening control of PMSM,the necessity of field weakening control is firstly analyzed.The basic principle,implementation process and control range of field-weakening control are introduced by means of curve analysis method of current limit circle and voltage limit circle;Based on the control method,the vector control strategy of PMSM with field-weakening control was analyzed and deduced;in order to improve the output capability of the inverter.the over-modulation principle and method of the inverter were studied and applied to the field-weakening control strategy of the permanent magnet synchronous motor.In the MATLAB/SINMULINK environment,a special simulation study was performed on the realization of SVPWM technology and over-modulation technology.Finally,the SIMULINK simulation model of the field-weakening control strategy is built for the hidden-pole and salient-pole PMSM,and the effectiveness of the field-weakening control system is verified by simulation.