Speed Control of Permanent Magnet Synchronous Motor using Vector Control for Electric Vehicle

Abstract

This thesis focused on the control of PMSM using vector control(FOC) method with field weakening Techniques for Three Wheel electric vehicle (EV) application .A PMSM mo tor model has been Studied and analyzed to control the motor both in the constant-torque (constant flux) and in the constant power (flux weakening) regions.The objective of the field weakening technique is then to control id and iq current in such way that the motor can develop constant power and achieved wide speed range operation.Surface mounted PMSM have been used in this thesis that is Lq = Ld so that reluctance torque due to in ductance considered as zero.The analysis of Vector controled flux weakening techniques PMSM drive system shows that the armature current is controlled to have a field com ponent that weakens the air gap field, and therefore opposes the back emf. However, the armature current vector must satisfy the voltage and current constraints. Due to the upper limit set on the available dc link voltage and current ratings of a given inverter are limited.The voltage and current limit affect both the maximum speed and rated torque operation.So that inorder to achieved those constraint flux weakening have been applied in constan power operation region.The simulation result have been showed that the speed range improved from 3900RPM(base speed) to 5000Rpm(Maximum speed).Therefor the result showed that using flux weakining method we could increased the speed range with in desired power rating of the motor.