Multipulse inverter can output staircase wave under low switching frequency mode with the phase shift transformer’s secondary winding turn ratio accurately design, then the high quantity sine wave can be obtained at the AC side of the inverter after AC side filter. But suffering from the fundamental switching mode the multipulse inverter’s output voltage regulation is difficult. On the other hand as the number of it’s pulse increased the structure of the phase shift transformer becomes complex and the turn ratio of transformer’s winding cannot be designed accurately. The channel number of the multipulse inverter is usually below four. This paper presents a modular 48-pulse high-power PWM inverter with only two kinds of phase shift transformer which has the structure of 8-channel three phase inverter and phase shift transformer accordingly. The proposed inverter shows great virtue of voltage regulation benefited from low switching frequency PWM modulation strategy. A 50 kilowatts 8-channel mutlipulse inverter prototype is constructed, the test data and waveform in many operating modes validated the proposed modular multipulse inverter’s advantages in output waveform, switching frequency and regulation performance etc.
