| Recently, brushless DC motor has been applied in many area. Besides the good performance of startup and speed control, its remarkable characteristic is that there is no commutator and brush. So the brushless DC motor has some advantages such as long life, low noise, reliable operation and easy maintenance. Its speed can be regulated in a large range smoothly because of no limitation of mechanical commutator. For the electric bicycle, the motor with brush has been replaced by the brushless one. Due to the commutation without touch, the life of motor is prolonged and the motor is easy to be controlled.A brushless DC motor control system based on PIC singlechip and PWM control is introduced in this paper. Some functions such as voltage commutation, overload protection, under voltage protection, speed up, speed control and locked rotor protection are achieved.Both hardware and software are shown in this paper. Hardware design includes power supply, Handle input, driving circuit, overload protection, under voltage protection and commutation circuit. Software design includes driving circuit, soft starting, speed up and down, speed reference detection, power supply voltage detection, locked rotor protection and brake control.Hardware diagrams and program flow charts are shown. Mathematical model of system simulation and simulation design by using MATLAB Simulink are introduced and the simulation waveforms are analyzed. Appendices include some program block writing by author, some program, some assembly macro definition segments, and published academic papers during the course of research.By system simulation, theoretical analysis and system debugging, the control system is stable and reliable. The desired functions are design indices are achieved.
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