Predictive Control of Parallel Three-Phase Grid-Tied Inverters : A Simple and Effective Solution to Mitigate Circulating Current

Abstract

High power grid-Tied inverters have attracted increasing attentions in energy conversion and electrical drives applications. Parallel configuration is a promising solution to enlarge the total power rating. However, zero-sequence loop arises in paralleled grid-Tied inverters, hence introducing zero-sequence circulating current. This leads to the deceases of the effective power volume and additional power losses. An effective solution based on predictive control framework is proposed in this work, and it successfully eliminating the circulating current. The proposed method decomposes the voltage vector into two parts, i.e., the former is used for reference current tracking, and the latter is responsible to suppress the circulating current. It is straightforward to be implemented in low-cost processors, and flexible to balance the importance of control performance and bus voltage utilization. We validate the controller on a lab-constructed test bench. The experimental results confirm the effectiveness and robustness of our proposed solution.