Power Imbalance Compensation of Droop-Based Distributed Control With Wireless Communication in Multi-Cell AC-DC Converters

This paper proposes an enhanced distributed control scheme with power imbalance compensation for an Input-ParallelOutput-Parallel (IPOP) AC-DC converter featuring a power imbalance compensator that incorporates non-instantaneous values. Power-sharing imbalances are a common issue in parallelconnected cell converters due to wiring resistance between the load and individual cells under conventional droop control. The proposed compensator, placed in the outer loop of the voltage and current feedback loops, effectively mitigates these imbalances. By leveraging non-instantaneous values, the control scheme accepts low-bandwidth communication, enabling the use of low-speed wireless modules and reducing the required signal lines, thus enhancing system flexibility. The experimental validation is conducted using a 7.2-kW prototype comprising six cells with integrated wireless communication modules. The results demonstrate that the proposed method reduces output current imbalance by up to 94% compared to conventional approaches.