A Power Balancing Method for Cascaded Inverters Based on Carrier Vertical Adjustment

This study addresses the power imbalance issue among cascaded units in cascaded H-bridge (CHB) inverters employing traditional phase disposition (PD) modulation. A novel modulation strategy based on vertical carrier adjustment is proposed. Taking a four-unit CHB inverter as an example, the strategy first optimizes traditional PD modulation by reducing the required number of triangular carriers. Subsequently, by vertically redistributing carriers across cascaded units, detailed analytical expressions for the duty cycles and average output power of each unit are derived over the full modulation index range, proving that the method achieves power balancing within one output cycle. Finally, simulations and experiments validate the effectiveness and feasibility of the proposed approach.