Pre-synchronization Control Strategy of CHB-BESS Based on Voltage Source Control

The cascaded H-bridge battery energy storage system (CHB-BESS) is considered an up-and-coming solution for high-capacity energy storage due to its high efficiency and modularity advantages. CHB-BESS, based on voltage source control, helps improve power system stability. However, when the inverter is connected to the power grid, minor voltage deviations can cause significant impacts, which may lead to equipment protection disconnecting from the power grid or even being damaged. The current pre-synchronization technology mainly aims at two or three-level converters with capacitor filters, which cannot directly apply to CHB-BESS with multi-level output characteristics. This article proposes a pre-synchronization control strategy for CHB-BESS, which effectively avoids the problem of startup overcurrent. Finally, a simulation model was established in PLECS to verify the effectiveness of the proposed control strategy.