The Research on Control System of Brushless Direct Current Motor Driving

The control system used in air compressor driven by brushless direct current (BLDC) motor was designed in this paper. Based on the analysis of resistance characteristic of air compressor and direct torque control method, a simple open loop control method used to change duty ratio was provided. Simulation and experiment showed that the fluctuation of Rotational speed had been sharply reduced and the opposing torque output had almost disappeared when different duty ratio in different operational position to drive the BLDC MOTOR was adopted. In that way the air compressor can work more stably without disturbance from opposing torque, which provides the motor with high efficiency as well as sparing cost and reducing the size of system.