A Simplified Modulated Model Predictive Control for a Grid-Tied Three-Level T-Type Inverter

Abstract

The implementation of finite-control-set model predictive control (FCS-MPC) in grid-tied inverters can make the system to suffer from poor harmonics performance, which may complicate the AC filter design for compliance with strict harmonic standards. To overcome this shortcoming, a simplified modulated model predictive control strategy is proposed in this paper. This control strategy not only improves current waveform total harmonic distortion (THD) without introducing additional weight factor in the cost function but can also shorten running/computational time without compromising the performance of fast current dynamic response. Herein, the detailed implementation of this control strategy is given, while considering its application to the current feedback control loop of a three-phase three-level T-type inverter modulated at constant switching frequency. Finally, PLECS circuit simulations are used to verify the feasibility and effectiveness of the proposed control strategy and to benchmark its performance to the classical FCS-MPC strategy and the application of a PI-controller.