PROJECT TITLE :

Non-isolated Bidirectional Soft-Switching Current-Fed LCL Resonant DC/DC Converter to Interface Energy Storage in DC Microgrid

ABSTRACT:

This paper proposes a current-fed non-isolated soft-switching bidirectional dc/dc converter for interfacing energy storage to dc microgrid. The proposed converter employs a current-fed half-bridge boost converter at front-end followed by an LCL resonant circuit to assist in soft-switching of semiconductor devices. A voltage doubler at output is chosen to boost the gain by two×. The LCL resonant circuit also adds a appropriate voltage gain. Therefore, the topology offers overall high voltage gain without transformer or massive number of multiplier circuits. For buck operation, high side voltage is initial divided by 0.5 with capacitor divider to gain higher stepdown ratio. Converter operates at high switching frequency to appreciate deserves of reduced magnetics and filters. Zero voltage flip-on is achieved for all switches and 0 current flip-on and flip-off is achieved for all diodes for both buck/boost operation. Voltage across switches and diode is clamped naturally while not any external snubber circuit. Detailed analysis and style have been proposed. A symptom-of-concept experimental prototype rated at 350 W has been designed, developed, and tested in the laboratory to demonstrate the performance and validate the claims of the converter for wide load variation.