DSP-based closed-loop control scheme oAbstract—High-boost dc-ac inverters are used in solar photovoltaic
(PV), fuel cell, wind energy, and uninterruptible power
supply systems. High step-up and step-down capabilities and
shoot-through immunity are some of the desired properties of an
inverter for a reliable, versatile, and low-distortion ac inversion.
The recently developed Z-source inverter (ZSI) possesses these
qualities. However, the realization of ZSI comes at a cost of higher
passive component count as it needs two sets of passive filters. A
switched boost inverter (SBI) has similar properties as ZSI, and
it has one L-C pair less compared to ZSI, but its gain is less than
ZSI. This paper proposes the current-fed switched inverter (CFSI)
which combines the high-gain property of ZSI and low passive
component count of SBI. The proposed inverter uses only one L-C
filter and three switches apart from the inverter structure. The
inverter topology is based on current-fed dc/dc topology. Steadystate
analysis of the inverter is presented to establish the relation
between the dc input and the ac output. A pulse width modulation
(PWM) control strategy is devised for the proposed inverter. An
experimental prototype is built to validate the proposed inverter
circuit in both buck and boostmodes of operation. A 353-V dc-link
and a 127 V (rms) ac are obtained from a 35.3-V dc input to
demonstrate the boost mode of operation. A 200-V dc-link and a
10.5-V (rms) ac are obtained from a 37.8-V dc input to verify the
buck mode of operation of CFSI.
Index Terms—Current-fed dc/dc topologyf CFSI.