SPSM-MPC Optimization Strategy for MMC Grid-connected Inverters

In order to solve the various disturbance problems faced by the grid-connected inverter with Modular Multilevel Converter (MMC) topology, such as load mutation, an optimization strategy based on the combination of Slope-compensated Passivity-based Sliding Mode Control and Model Predictive Control (SPSM-MPC) was proposed. In this strategy, passive sliding mode control is used as the main structure of the current inner loop, and on this basis, slope control is introduced to construct a Slope-compensated Passivity-based Sliding Mode (SPSM) controller, which effectively suppresses the chattering problem and improves the output accuracy of the system. Furthermore, Model Predictive Control (MPC) is used in the nearest level approximation modulation link, which further improves the grid-connected power quality. The Simulink simulation platform was used to build the electromagnetic transient model of the MMC grid-connected inverter, and the simulation was carried out under normal operation and load mutation conditions. The results show that compared with the traditional PI and passive sliding mode control, the proposed control strategy effectively reduces the accuracy of output power and the robustness of the grid-connected inverter.