BLDC Motor Sensorless Control System Based on ADSP-BF548

In this thesis , the control strategy based on sensorless BLDCM(Brushless DC Motor) has been researched.A control system for BLDCM operating on ADSP-BF548 has been given. we focus on studying the control strategy of sensorless BLDC motor based on back-EMF detection, and present a control system for BLDC motor based on ADSP-BF548 special for motor control. The calculation method of back EMF in BLDC motor was deduced and the hardware circuit of line voltage detecting was designed. A pre-position starting tactics based on back EMF detection and a tactics of phase converting by postponing back-emf-zero-crossing detecting was designed. The signal wave was filtered by postponing back-emf-zero-crossing detecting when back-emf-zero-crossing had been detected. To release the phase delay caused by hardware filtering, a phase compensation algorithm has been designed. The PID adjusting algorithm and other strategy are designed in this program. Experimental results show that the control system has good speed adjusting performance and runs stably.