Current-Fed DC/DC topology based inverter

Abstract

New-age power generation systems based on renewable energy systems (RES) mainly constitute of wind generators, solar PV, fuel cells, etc. Energy harvesting from solar PV or fuel cell calls for high step-up inversion owing to its low-voltage input. Conventional voltage source inverter (VSI) can only produce an AC output smaller than its input DC voltage under normal operation. VSI also requires for dead-time compensation circuits as shoot-through of any inverter leg is detrimental for its operation. Recently developed ZSI and its derivatives overcome these problems by allowing shoot-through and providing output AC voltage with buck-boost capability. This paper proposes a Current-Fed DC/DC Topology (CFT) based inverter which shows similar gain characteristic and advantages as the ZSI. The proposed inverter requires only one LC-pair which is one less than the impedance network of ZSI. The proposed inverter is derived from CFT. Steady-state analysis and implementation of the proposed inverter are described. The PWM control strategy of the inverter is explained. An experimental prototype is built to validate the proposed inverter circuit. A 127 V (rms) AC-output is obtained from 353 V DC-link with 35.3 V DC-input and a 5.18 V (rms) AC-output is obtained from 57.6 V DC-link voltage with 28.8 V DC-input to verify boost and buck mode of operation, respectively.