Synthesis of Sliding Mode Control Strategy for T-Type Grid Inverter in Presence Grid Voltage Disturbance

The paper proposes a new hybrid sliding mode control algorithm based on saturated-type reaching law for current regulation of a grid-following inverter in a microgrid connected to the power grid, ensuring system stability under severe main grid voltage disturbances. The system contains the control system, T-type inverter, LCL filter, and DC source. First, a mathematical model of the above-described microgrid structure is proposed. The designs of well-known SMC algorithms used to control the power grid current are presented. This work introduces a new hybrid SMC method based on saturated-type reaching law, which is later used in the control system for a specific test scenario including voltage grid disturbance. For this case, an additional and extended stability analysis is conducted to obtain the controller parameters that shall provide the system with greater robustness and a faster convergence to the desired state after prior displacement. The primary objective of this study is to enhance the quality of transmitted energy in a power electronic system by means of a novel sliding mode control approach with a hybrid reaching law, while reducing the system’s sensitivity to selected external disturbances.