An improved current control algorithm for single-phase grid-connected inverters

This paper proposes an improved current control algorithm for single-phase grid-connected inverters. The new algorithm has a superior performance over commonly used predictive current control methods. Conventional predictive control suffers from the inherent control delay in a digital control system. The proposed control algorithm applies an appropriate digital controller to compensate for the influence of control delay. This paper introduces the design approaches for the digital current control, including system modeling, discretization, and disturbance decoupling techniques. Design case studies of both the conventional predictive current control and improved current control are presented in this paper. These two methods were both implemented on a 10kW grid-connected inverter for comparative studies. All the analytical and experimental results given in the paper have verified the effectiveness and superiority of the proposed current control algorithm.