Research on Modulation Strategy and Power Balancing Method Optimization of Cascaded H-Bridge Inverter

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Compared to symmetric cascaded H-bridge inverters (CHB), hybrid cascaded inverter technology can generate more voltage levels with fewer inverter units. In traditional inverter modulation strategies, hybrid cascaded inverters produce high-quality voltage output. However, due to power imbalance among cascaded units, the uneven power distribution accelerates unit degradation, thereby affecting the overall lifespan of the inverter. To address these issues, this paper proposes a novel modulation strategy. The low-voltage units undergo carrier reconstruction, while the high-voltage units employ modulation wave reconstruction, achieving power balancing across all units. The low-voltage units exhibit improved power-balancing response speed compared to traditional methods. Simulation results validate the effectiveness of the proposed approach.