Modular cascade power amplifier switch combination rotation multi-level modulation method

The invention discloses a modular cascade power amplifier switch combination rotation multi-level modulation method which is applied to a modular cascade power amplifier, the output side of the modular cascade power amplifier is formed by cascading N DC/AC module units, each DC/AC module unit is of a full-bridge inversion unit structure and is composed of a left bridge arm branch and a right bridge arm branch, and the left bridge arm branch and the right bridge arm branch are connected in series. According to the method, multi-level modulation is divided into platform voltage modulation and pulse voltage modulation through a switch combination, on and off of each bridge arm are controlled under the constraint of a switch combination sequence, and switching frequency equalization of power devices between the bridge arms and power equalization between unit modules are realized. Meanwhile, modulation of the modular cascade power amplifiers with different level numbers can be realized by adopting a unified formul