Abstract: The traditional hybrid cascaded three-unit fifteen-level inverter requires a large number of switching tubes and there is a problem of unbalanced output power under the traditional modulation strategy. Aiming at the above problems, this paper proposes a seven-switch fifteen-level inverter topology and power balance method. The idea of the inverter structure is as follows: firstly, the DC source, switching tube and diode are combined to from a basic cell to output positive level, and then the level is changed to positive and negative levels by an H-bridge to achieve the function of outputting multilevel, which greatly reduces the number of switching tubes. This paper adopts a modulation strategy of combining the step wave synthesis and specific harmonic elimination. Simulation and experimental results show that power balance of three different-voltage-grade units of the inverter can be achieved within a half cycle, and the low-order harmonic content of the output voltage can be reduced.