Cascaded Multilevel Topology Based on Quadruple Active Bridges for Phase Power Balancing in Large-scale PV Systems

Cascaded H-bridge (CHB) converters are promising candidates for large-scale PV system integration. However, unequal power generation from different arrays can result in imbalanced three-phase grid currents. Therefore, a multilevel converter architecture based on quadruple active bridge (QAB) converters is proposed in this paper, which can actively distribute the generated power equally to three-phase H-bridge cells and ensure balanced grid currents. For the design of the converter, Zero Voltage Switching (ZVS) and the reactive current ratio of QAB converters in the whole operation range are analyzed and design recommendations are provided. Simulation and experimental results validate the effectiveness of proposed topology.