DC/DC Converter for Bipolar LVdc System With Integrated Voltage Balance Capability

Abstract

Bipolar LVdc distribution is a promising solution for better integration of renewables and enhancement of system efficiency and reliability, but it also faces the challenge of pole voltage imbalance. By simple modifications of the bidirectional CLLC dc/dc converter, this article presents a dc/dc converter with integrated pole voltage balance capability. The converter presents less number of semiconductors, smaller overall footprint, and lower power loss compared to the employment of additional pole voltage balancers. Operating principle of this dc/dc converter and its inherent pole voltage balancing capability are explained, while further control scheme is also developed to compensate the small pole voltage difference caused by the dead time effect. Simulation results with 150\xa0kW/±375 V bipolar output demonstrate the effectiveness of the converter, and the experimental results from a 500\xa0W/±50 V downscaled prototype further prove the proposed concept.