More Efficient Power Inverters using Series Connected AC Capacitors for Large DC Voltage Variation Applications

doi: 10.14456/mijet.2017.1

Abstract

Conventional power inverters such as a voltage source inverter and a current source inverter may operate only with low efficiency when converting power from large DC voltage variation sources to constant AC voltage outputs. This is because large difference in voltage levels between the DC side and AC side of the inverters can occur and reduce voltage transfer capability of the inverters. Additional circuits such as a boost or a buck converter could be used to adjust DC voltage to the suitable levels for the inverters, but they add more cost, power loss and complexity to the inverter circuit. This paper proposed an alternative technique that allows the inverters to always operate with optimum voltage levels between the DC side and AC side. The proposed technique can achieve this by connecting an AC capacitor in series with each of output AC phase line of the inverters. Simulated results shows that the proposed technique provides improved efficiency and less voltage stress on inverter circuits compared to the conventional circuits.