Current-Sharing Control of Modular Parallel Inverter System Based on Current-Sharing and Synchronization Buses

In order to achieve the average power distribution in the parallel inverter system, this paper proposes a currentsharing control strategy for a modular parallel system based on current-sharing and synchronization buses. The system employs a non-fixed master-slave control approach, where in the event of a master module failure, slave modules automatically compete to take over as the master, ensuring the stability of the system. The master module sends a power frequency square wave signal through the synchronization bus. Upon receiving the synchronization signal, the slave modules synchronize their phases based on the rising edge of the signal. At the same time, the master module uploads the calculated voltage amplitude reference as a signal to the current-sharing bus. The slave modules then retrieve the signal and input it into their local control, which exhibits strong noise immunity. Through the combined operation of virtual impedance control, phase synchronization based on the synchronization bus, and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$P Q$</tex> droop control and voltage compensation modules implemented through the current-sharing bus, the parallel system achieves effective current-sharing. Finally, the effectiveness of the proposed method is validated through experiments.