Sliding Mode Control of Permanent Magnet Synchronous Motor with Improved Variable Exponential Reaching Law

Given that sliding mode control system with traditional exponential reaching law has excessive chattering and slow convergence speed, which reduces the speed regulation performance of permanent magnet synchronous motors, an improved variable exponential reaching law is proposed. First, this paper analyzes the factors that affect the system’s chattering in the traditional exponential reaching law, and modifies the reaching law structure in a targeted manner; second, to avoid the influence of the inherent switching characteristics of the sign function, the hyperbolic tangent function is used to replace, which further suppresses chattering and improves tracking accuracy; finally, the mathematical model of the sliding mode controller is established and the simulation experiment is carried out on the Matlab/Simulink platform. The simulation results show that, compared with the sliding mode control system based on the traditional exponential reaching law and PID control system, the sliding mode control system based on the improved variable exponential reaching law could effectively suppress chattering, reduce overshoot, and has better robustness against parameter variation and external disturbances.