A Novel Model Predictive Control on Single Phase Inverters for Reducing THD

Inverters are commonly used in renewable energy systems as interface. Total Harmonic Distortion (THD) is a key index of judging its effectiveness. In this paper, a direct THD oriented MPC method is proposed. Firstly, a cost function which is a linear combination of DC bias, fundamental frequency deviation and THD of one cycle (20ms at 50Hz) is designed and the weight factors are obtained by offline calculation. Secondly, the iterative algorithm of cost function is derived to ensure real time control. Then, the switching states as the control law from the finite control set of the input by solving a finite horizon optimization problem is chosen. Simulation results under MATLAB/Simulink show that the proposed method has better performance than the traditional standard error oriented MPC method.