Three-Phase Four-Wire AC-DC-AC Converter with Shared Legs

This work proposes a seven-leg three-phase fourwire AC-DC-AC converter. The converter has three legs shared between grid and load sides. This topology presents double voltage amplitude generation capability at grid side compared to load side. In this way, the converter develops its best performance when the amplitude of grid voltage is twice of the amplitude of load voltage, because this operation allows to reduce semiconductor losses, and harmonic distortion of the converter voltages and to use all voltage generation capability at both sides simultaneously. Converter model, control stategy and PWM technique are explained. Analysis are performed considering DC-link voltage and synchronization, harmonic distortion, semiconductor losses and average switching frequency. Finally, simulation and experimental results are shown to validate the analysis.