Sensor-less brushless DC motor control system design for electric vehicle

This paper, based on the performance characteristics of electric vehicles, provides a rather integrated set of control strategies of sensor-less brushless DC motor for electric vehicles. It probes into the key technical issues of sensor-less brushless DC motor control — the rotor position detection, starting and braking control strategies, accelerating demagnetization method and the speed-current double-loop speed control. Also, it improves the control methods on the basis of some traditional ones to make it more suitable for electric vehicles which require high-speed, steadiness and power-saving, meanwhile introduces the improved hysteresis current control to perfect the motor performance characteristics. The emulation results show that this control algorithm can meet the work requirements of electric vehicles while the motor working under expected state.