Design and implementation of double closed-loop system of brushless DC motor based on sliding mode control

In this paper, sliding mode control (SMC) is used in double closed-loop system of brushless dc motor(BLDCM), which improves speed tracking performance of BLDCM. Kinetic equation of motor is established according to mathematical modeling of motor, then design sliding mode controller by using kinetic equation. Sliding mode controller regulates speed in speed loop, and SMC strategy makes speed control of BLDCM have many advantages of quick response, strong robustness, small overshoot and so on. Current loop regulated by proportional-integral-differential(PID) control lets BLDCM limit maximum current to automatically protect system when BLDCM is in a state of overload. Through simulation with Matlab, it is obvious to see that system designed by this proposed scheme has better control effect than double closed-loop system all using PID control. Experimental platform is set up by K60 microcontroller, and it verifies feasibility of controller in actual control.