A flexible fast digital controller for a brushless DC motor

The authors describe a completely microprocessor based speed controller with efficient hardware and software structure for a brushless DC motor. The system is designed to accommodate higher processing speeds and other enhancements. A Motorola 68000 16-bit processor handles the system including high speed data acquisition and a PWM current control scheme which uses a novel approach based on the voltage vector method. The feedback speed control scheme, features a proportional+integral (P+I) controller with adaptive magnitude limitation to avoid current saturation and provides good performance with small overhead of processor time. In addition, the incorporation of torque ripple minimisation enhances low speed controllability