A dual balanced control method for power and switching loss of cascade H-bridge inverter based on redundant voltage vector degree of freedom optimization

The carrier in-phase superposition modulation strategy of cascaded H-bridge inverter has good output harmonic characteristics, but there are problems of uneven output power of cascade unit and unbalanced switching loss. To overcome these problems, a dual balanced control method for power and switching loss of cascade H-bridge inverter based on redundant voltage vector degree of freedom optimization is proposed. Firstly, the inverter modulation wave is vertically translated and the number of carriers is reduced to lower the difficulty the modulation algorithm. Secondly, the freedom of carrier is optimized by using the combination of redundant voltage vectors, and the arrangement of carriers in vertical and horizontal directions adjusted. Thus, the power balance and switching loss balance are realized in the full modulation range without affecting the output voltage power quality; the correctness and effectiveness of the proposed method are verified by simulation and experimental comparison analysis.