Arm Voltage Balance Control of a Modular Multilevel Matrix Converter with Inner and Outer Loop Double Adjustment Based on Circulating Current

Abstract

This paper presents a control strategy of inter-arm voltage balance for a modular multilevel matrix converter (M3C) based on injected circulating current. The proposed method is divided into two parts, balancing the inter-arm voltage through the current control loop and the voltage control loop respectively. The strategy improves the current performance of the grid on both sides by enforcing the injected power to flow only within the nine arms, which is simple to control and suitable for various working conditions including stable operation and faults. Comparative simulation results obtained using Matlab/Simulink prove that the proposed control strategy can significantly reduce the inter-arm voltage imbalance, which demonstrates the performance and effectiveness of the strategy.