Sliding mode speed control for brushless DC motor based on sliding mode torque observer

Brushless DC (BLDC) motor control system is a multi-parameter nonlinear systems, and the ultra-low inductance of it makes more stringent requirements on the performance of the control system, which make it difficult using the traditional PI control method and the intelligent control methods, such as fuzzy control method and neural network control method, to effectively control a low-inductance BLDC motor with high performance demands. Considering this, we propose a new dual-loop control strategy in which the current hysteresis control is adopted for the current loop, and the speed loop control is realized based on the exponential approach law sliding mode speed controller and sliding mode observer to construct the control system for a low-inductance BLDC motor. The simulation and experimental verification show that compared to the traditional PI control strategy, the proposed control strategy shows obvious advantages in overshoot control, response speed and adaptability to load variations.