Energy Storage Converter Off-Grid Parallel Cooperative Control Based on CAN Bus

With the rapid development of the industrial sector, the single-inverter power device is increasingly unable to meet the industry’s high-power needs due to the power limitations of semiconductor devices; as a result, parallel connection of multiple devices has become the main means of expanding the capacity of power conversion systems. To address the issues of circulating current and power imbalance caused by discrepancies in the output voltage amplitude and phase among power conversion system (PCS) modules, this paper proposes a master–slave mode-based collaborative control method for energy storage inverters operating in parallel—the method consists of two main components: phase synchronization control and equal amplitude control. The master sends the synchronization signal and voltage amplitude to the slave inverters via the CAN bus, and each slave then adjusts its phase based on the synchronization signal and calculates the modulation ratio of the wave according to their own power supply conditions. This ensures that the output voltage amplitude, phase, and frequency of all slave inverters are fully aligned. Experimental results validate the effectiveness of the proposed parallel coordinated control method, ensuring the stable operation of the parallel system.