Model predictive control for single-phase three-level grid-connected F-type inverters

Abstract

This paper presents a model predictive control (MPC) method for single-phase three-level grid-connected F-type inverters. The main control objective in grid-connected inverters is to regulate the grid current with low total harmonic distortion. Since the F-type inverter has emerged recently, there is no specific control method developed for this inverter topology in the literature yet. In this paper, the mathematical model of the F-type inverter and the design of model predictive control is presented. Since the dc capacitor voltage balancing is essential for F-type inverters, both current control and dc capacitor voltage controllers are combined in a multi-objective cost function. Thus, the control of the dc and ac sides of the F-type inverter is achieved successfully. The theoretical considerations were verified through simulation studies. The effectiveness of the proposed MPC method was investigated in the steady state as well as dynamic transients under variations in grid current, input dc voltage, and grid voltage. The simulation results show that the grid current and dc capacitor voltages are successfully controlled in all operating conditions.