Design of digital controller for sensorless brushless DC motor speed regulation

Based on the analysis of brushless DC motor back-EMF detection method,the hardware detection circuit and the microcontroller-based digital speed controller of brushless DC motor are designed.The detection and control units of the digital speed controller are introduced respectively,and details of EMF detection methods and the realization of single-chip generating PWM signals to control the driving bridges in this control scheme are introduced.The design also adds the supporting PC software..The result proves that the controller can realize the motor speed regulation,power supply voltage undervoltage protection,overcurrent protection,speed display,PC control and so on.