A sliding mode speed controller based on novel reaching law of permanent magnet synchronous motor system

This paper presents a new control methods based on a novel reaching law to overcome slow convergence rate and severe chattering in sliding mode control of permanent magnet synchronous motors (PMSM). The constant reaching law converges slowly during large systematic errors. Although the power reaching law converges fast during large error, it chatters severely while approaching to the sliding surface. Based on mentioned reaching laws, the state variable has been introduced. It can accelerate the rate of convergence when the system is away from the sliding surface. Furthermore, the stability can be satisfied in a way like constant reaching law when the system approaches to the sliding surface. Simulation results show that the novel reaching law improves dynamic performance and enhances systemic robustness obviously.