Sliding mode control of permanent magnet generator system based on improved exponential rate reaching law

This study focuses on the improvement in the transient performance of DC-link voltage for a permanent magnet generator (PMG) system. Based on the vector control theory and double closed-loop control, the sliding mode control (SMC) method with the improved exponential rate reaching law (IERRL) is proposed in the voltage loop of the PMG system. The switching surface is designed with an integral term of state variable to suppress chattering and increase response speed. In addition, the IERRL that combines the concept of constant-proportional rate reaching law and exponential reaching law is proposed to further suppress chattering and eliminate steady-state tracking error of DC-link voltage. A detailed analysis of control law, system stability, reaching time, and chattering on switching surfaces are presented as well. The SMC method with IERRL improves the transient performance under sudden load changing occasion and eliminates the steady-state tracking error of DC-link voltage. Simulation and experimental results verify the effectiveness of the proposed method.