The hybrid cascaded H-bridge seven-level inverter with a voltage ratio of 1:2 has a DC-side current sinking problem in the hybrid modulation. The mixed-frequency modulation can effectively solve this problem

but can lead to decrease in the output power quality. The LS-PWM frequency doubling modulation can improve the equivalent output switching frequency of the high voltage unit and improve the output voltage waveform quality

however

the high voltage unit will still operate in a high frequency state in some sections

increasing the switch losses. To solve the above problems

a hybrid cascaded H-bridge thirteen-level inverter topology with a voltage ratio of 1:1:2:2 and a hybrid modulation method in combination with stepped wave modulation and carrier-stack modulation are proposed. Thereby

not only the current backflow problem is solved

but also the high voltage unit is ensured to be in operation in the fundamental frequency state. And the method of cyclically exchanging the driving signal of switching tube by using 1/4 output voltage cycle can be adopted to solve the power balance problem between the same voltage level units. The simulation analysis and experimental results prove the correctness and feasibility of the theoretical analysis.