Control of Micro Power Inverter Based on Model Prediction

In traditional control methods for micro power inverter there were such shortcomings as complicated design and low robustness, to make micro power inverter possessing fast and accurate response it was proposed to lead model predictive control (MPC) into the inverter. According to the requirements of grid-connected and island operation of the inverter, the model predictive PQ control scheme and the U/f model predictive control scheme based on the droop characteristics were designed, and by means of the inductor and capacitor in the LC filter the differential equations were established and corresponding mathematical prediction model was derived. During the grid-connected operation the output current of the controlled inverter traced the reference current generated by power instruction; during the islanded operation the controlled inverter traced the reference voltage and frequency generated by power controller. Simulation results show that both control schemes achieve effective tracking, and the system response is fast, the overshoot is small and the control accuracy is high. The feasibility of the proposed control strategies is proved by simulation results, and the proposed control strategies make the inverter system achieving a good control effect.