Position Sensorless Hybrid Sliding Mode Control Of Brushless DC Motor

Brushless DC motors (BLDCM) are widely used in every walk of life in view of its excellent qualities such as high operating efficiency, no spark during commutating, and good mechanical properties. Generally, traditional control strategy can be achieved by getting the exact commutation signal with the mechanical position sensors. However, the mechanical position sensors may restrict BLDCM’s application in some areas, such as aerospace, automobile. These may hinder the development of BLDCM. Sliding Mode Control (SMC), which is strongly robust to system parameters variations and external disturbances, has a desirable perspective in BLDCM control field. But the traditional SMC has the chattering phenomena. To solve the above problems, a new method for sensorless control of BLDCM is designed on the basis of the characteristics of hybrid nonsingular fast terminal high order sliding mode control.To solve the detection of rotor position and speed of BLDCM position sensorless problems, combination nonsingular fast terminal sliding mode and high order sliding mode, an improved estimation method of rotor position and speed based on sliding mode observer is proposed. The simulation illustrates that the hybrid sliding mode observer can accurately estimate the rotor speed and the rotor position.Then, using the observed speed and rotor position as feedback input and considering the effect of electrical parameter perturbations on the drive performance, the nonsingular fast terminal high order sliding mode speed controller and position controller are constructed. To achieve speed/position robust control of Brushless DC motor. The simulation illustrates, comparing with the PI controller and sliding mode controller, the hybrid nonsingular fast terminal high order sliding mode controller can make the BLDCM control system without overshoot, quick velocity response, and good robustness.