Voltage Control of Microgrid Inverter System Based on Improved Sliding Mode Control and Composite Nonlinear Feedback Control

ABSTRACT To enhance the robustness of the microgrid inverter system in islanded operation mode and speed up the response of the system, a novel voltage control strategy based on improved sliding mode control (SMC) and composite nonlinear feedback control (CNFC) is proposed. This strategy is specifically designed for the microgrid disconnected from the public grid. To achieve a fast system response, an attenuation function is designed to adjust the strength between linear and nonlinear feedback terms in CNFC under different conditions. To improve the anti‐interference ability of the system and suppress the chattering phenomenon, an adaptive reaching law (ARL) is designed by constructing a variable power term and introducing a hyperbolic tangent function, and the convergence of the ARL is proved by the Lyapunov stability analysis method. Furthermore, a collaborative sliding surface is designed to combine the improved SMC and CNFC for regulating the voltage output of the microgrid inverter system. The simulation experiment results show that the ARL has a smaller control error than that of the commonly used sliding mode reaching law, introducing CNFC into SMC can significantly improve the convergence speed of the system, and the steady state performance of SM‐CNFC is also superior to SMC, CNFC, and super twisting SMC methods. Therefore, the novel voltage control strategy can effectively suppress voltage fluctuations caused by load variation and parameter perturbations in the microgrid inverter system and improve the power quality of the microgrid.