Multistage three-phase controlled stepped-wave inverter system

This paper presents a multistage pulse-width modulated system for generating three-phase controlled stepped voltage waveforms. A four stage system is discussed. Voltage control is achieved by pulse-width modulation. Harmonics are eliminated by suitable transformer connections. In the four-stage system the eleventh and thirteenth harmonics predominate in its three-phase output voltage waveforms. The advantages of the proposed system ore discussed. The results are experimentally verified and compared with the conventional systems.