Single phase VSI with reduced-size DC-link capacitor

This paper presents a voltage source inverter in a single phase system for photovoltaic applications. The singlephase H-Bridge is augmented by an additional leg from which greater degree of freedom has been achieved in terms of modulation strategy. This new topology demonstrates the feasibility to avoid the double line frequency ripple, which commonly exists in single phase systems. Hence, the DC link capacitor can be sized based on the switching frequency rather than the lower double-line-frequency. Thus, the size of the dc link capacitor can be significantly reduced. Furthermore, it the reduced capacitor size allows for replacement of the electrolytic capacitors with much more reliable film capacitors.