Study On Permanent Magnet Brushless Motor For Electric Vehicles

At present, the energy crisis and environmental pollution problems have become increasingly prominent, high efficiency, energy saving, environmentally friendly electric vehicles are becoming widely concerned problems. The performance of electric vehicles motor speed regulation system largely determines the performance of electric vehicles, therefore, selecting high-performance motor control system has become key issues in electric vehicle design. Permanent magnet brushless DC motor consists of permanent magnet brushless DC motors and brushless synchronous motors. They do not have mechanical reversing mechanism as traditional DC motors, with the advantages of solid structure, wide speed regulation range, low-speed performance, high power density, easy maintenance and so on, suitable for electric vehicle drive motor.In this paper, concerning the characteristics of application of permanent magnet brushless DC motor and brushless synchronous motor in driving electric vehicles, the following contents are studied:(1) connected by winding method for improving the contradiction between the characteristics of low speed high torque of permanent magnet brushless DC motor and high-speed operation to make it more suitable for electric vehicle drive. (2) the establishment of permanent magnet brushless DC motor-driven mathematical model of electric vehicle, the preparation of the corresponding simulation program for permanent magnet brushless DC motor windings for electric vehicle drive then run the application. (3) research on estimation of back EMF for without position sensor, for surface mount PMSM, in any synchronous rotating coordinate system using results of steady-state operation to estimate the back-EMF, and then the estimation of rotor position and speed, given control method of PMSM without position and speed sensor.Through theoretical analysis and simulation studies have shown that the control method is correct and superiority.