Four Quadrants Operation Control of High-voltage Transformerless BESS System

When the high-voltage transformerless battery energy storage system system operates at a high proportion of reactive power compensation, the structure of the battery cluster connected to the single-phase H-bridge converter results in that the battery current will reverse in a cycle of twice the fundamental frequency. The battery is charged and discharged with high frequency, which will have a great impact on battery life and battery status monitoring. To solve this problem, this paper proposes a high-proportion reactive power compensation control based on inner-phase active power transferring and the charged and discharged current with twice the fundamental frequency is removed.