The Application Of Magnetic Encoders In Induction Motor Vector Control Of Electric Vehicles

This paper aims at improving the control method of the Electric Vehicle' drive system, based on the existing schemes. After comparing the principle of IGBT, traditional PWM and drive methods, we focuse on utilizing low-resolution magnetic encoder to replace optical encoder with 512 pulses per round.The rotor flux orientation method of induction motors is based on the feedback of rotor speed and position. We summarize the features of these two kinds of encoders and several typical Rotation Speed Measurement (RSM) methods, analyze the angle error of magnetic encoder with existing RSM. and evaluate its effect on the performance of induction motors. Then we bring up a new RSM method to improve the performance of induction motors with low-resolution encoder.Based on the rotor flux orientation method and SVPWM. we carried out simulation, programming, and experimental works. We simulate one 23/60Kw induction motor under the condition of different sensors with distinct RSM: we adopt TMS320F240 assemble language to revise the original program, adding hysteresis speed control and adapt the sampling time according to the speed; we experiment on' the YS90S2 and CDD-23 induction motors, compare performance of optical encoder and magnetic encoder with improved speed feedback method, and validate that its control performance is parallel with optical encoder and it is of practical value.