Model-independent sliding mode control for grid-connected crossover switches cell inverter with reduced switching frequency

Abstract

In this study, a finite control set-sliding mode controller (FCS-SMC) is applied to a grid-connected 9-level Crossover Switches Cell (CSC9) inverter. The proposed control technique is model-independent, as it selects the control actions based on the current state variables' errors rather than the past values. The control algorithm optimizes the control inputs to fulfill the reaching requirements of two designed cost functions that were derived based on the sliding mode (SM) theory. Moreover, a small permissible capacitor voltage error (hysteresis width h) is introduced to add an extra degree of freedom to the system, which allows the reduction of the average switching frequency without compromising the design requirements. The main advantages of the proposed method lie in its simplicity, absence of gain adjustment requirements, and straightforward design process. Simulation results are presented to demonstrate the effectiveness of the proposed SMC in achieving excellent dynamic performance and robustness against disturbances while controlling the capacitor voltage and grid current.