The Research Of Control System For BLDCM Based On MLX90316

BLDCM been widely used in many areas due to its good speed performance, small size, high efficiency, easy to control. However, traditional brushless DC motor control system at low speed circumstance can't achieve precise control performance though three-phase switch Hall effect sensor is widely introduced to provide information of position feedback . Photoelectric encoder, widely used at low speed circumstance in BLDCM system nowadays may acquire to the precise control, but its cost is burden. Therefore, sensors in new type, with low cost and high-precision capability, would demonstrate great significance in enhancing performance of BLDCM system.This thesis demonstrates the principle and output characteristics of a new type of sensor MLX90316, analyzes the static and dynamic error, investigates the installation of the MLX90316 and determines communication which is appropriate to motor control system. According to the principle of BLDCM and requirements for BLDCM system, a new control scheme based on the hybrid position measurement of MLX90316 and the Hall element position sensor is proposed. The scheme provides the foundation for BLDCM system to control precisely in full speed scope.In view of complex and time-consuming communication protocols for SPI in MXL90316, the principles and features of hardware in control system is demonstrate and the double interruption mode is proposed. The mode makes communication with less program time for the speed control module to ensure keyboard's scanning and protect and the various mistake displays and disposals prompt. Some key issues, involved with PWM modulation, dual-sensor with speed measurement switch, the start-up and braking for BLDCM, are fully elaborated and analyzed. Besides, the experimental results are presented with analysis and explanation. Experimental results indicate that dual-sensor control system has a series of strong points with rapid start-up, smooth switch, higher control accuracy.