Predictive Control of DC-link Voltage in an Active-Front-End Rectifier

Model predictive control (MPC) has been successfully applied to several power converters topologies, mainly because of the finite set of inputs which are given by the available switching states of these devices. However, MPC could not directly control the DC-link voltage in active-front-end(AFE) rectifiers, because they feature a non minimum phase behavior that produces an initial inverse dynamic and mislead the optimization stage selecting a wrong switching state. To avoid this effect, the DC-link voltage is usually controlled using a linear PI controller and an inner current or power control loop. However, the linear controller is difficult to design and presents a restricted dynamic behavior. In this paper, a DC-link voltage MPC is proposed. The proposed controller calculates the required active power reference based on the output power and the energy stored in the DC-link capacitor. Simulation results shows a good dynamic response and a zero steady state error.