Finite Set Model Predictive Control of PWM AC/DC Converter with Virtual-Flux Estimation under Grid Imbalance

The aim of this research is to improve the quality of input current for AC/DC PWM converter, in case of grid imbalance with high dynamic transient. This can be achieved by joining compensating power with finite set model predictive control (FSMPC) based on voltage sensor-less technique. The control scheme proposed in this paper is divided into two steps. First, a double second order generalized integrator is used to estimate the virtual-flux and separate sequences of grid current and then the compensating power necessary to obtain sinusoidal input current is calculated. In the second step, the current is regulated via FSMPC, where, the switching state is determined directly. MATLAB/Simulink is selected to simulate and verify the effectiveness of the proposed control scheme; with and without virtual flux estimation. Simulation results are compared to confirm the validity of the algorithm.