Modeling and Parameter Design of Voltage-Controlled Inverters Based on Discrete Control

Grid-connected inverters are widely used to interface renewable energy and energy storage resources into the grid. Voltage-controlled inverters have attracted more and more attention due to their grid-friendly characteristics. The mathematical models of the voltage and current loops are developed in this paper, considering especially the discrete control delay caused by calculation and modulation. In order to suppress the resonance peak in the current loop, the frequency characteristics of the current loop are analyzed in detail. The optimum design flow of the current controller and voltage controller parameters are presented based on numerical analysis, and the stability, dynamic performance and the resonance peak suppression in voltage loop are also considered. Finally, the validity of the mathematical model and the effectiveness of the controller parameters design method are verified by simulation and experimental results.