A new two-stage voltage source inverter with modulated DC-link voltage and reduced switching losses

This paper proposes a new DC/AC power converter topology that is obtained by merging a buck type DC/DC converter and a DC/AC three-phase PWM Voltage Source Inverter (VSI) without the need of the passive components (smoothing inductor and capacitance) between the two stages. The novel topology is characterized by less hard switchings needed to synthesize the desired output voltage states, mostly because the average voltage seen by the VSI is modulated in such a way that enables the elimination of its zero voltage state and allows for some zero voltage switchings, reducing the switching losses, that makes this topology more suitable for higher frequency operation, which would ultimately reduce the size of the converter in applications where a load side output filter needs to be fitted