Robust Control of Voltage Source Converters: A Tube-Based Model Predictive Approach

Finite control set-model predictive control (FCS-MPC) operates based on the assumption that optimal control responses executed on a prediction model match closely an actual system. Thus, model uncertainties and external disturbances affect the controller's performance. To weaken the impact of uncertainties, this brief proposes a tube-based FCS-MPC to control the output voltage of a voltage source converter (VSC). The proposed controller is composed of two FCS-MPCs. The first one generates an initial control action and a prediction of the output voltage based on a system, including no uncertainties. This control action and the output voltage are then sent to the second FCS-MPC, together with the output voltage of the uncertainty-involved system, to choose the best switching states of the VSC. Simulation and experimental validations demonstrate the proposed method's effectiveness and robustness compared to a conventional FCS-MPC.