Fault-Tolerant Multiport DC–DC Converter With Reduced Current Ripple and Step-Up/Down Voltage Gain Charging Capability

This paper develops a novel fault-tolerant multiport bidirectional dc-dc converter (FTMBDC) with reduced current ripple. This converter has the capability of charging the battery with step-up/down voltage gain with reduced charging current ripple. The bidirectional behaviour of the converter enables the charging and discharging operation of the battery with the source and load, respectively. The interleaving at both side ports of the converter improves the performance, reliability, and efficiency. The proposed converter provides fault-tolerant capability against each semiconductor switch failure. The analytical analysis of the proposed converter is developed with the consideration of circuit parasitic. A small-signal model (SSM) and corresponding nominal transfer functions are derived using a switched linear system model. The stable regions of controllers are developed using the stability boundary locus method. It provides robust performance region for closed-loop operation of the converter for circuit uncertainties. The behaviour of the current ripple with respect to duty variation is presented. The switched-boost action topology uses time multiplexing of boost and buck switches to produce regulated voltage at both the output ports. The closed-loop control is designed for the regulated voltage and current with battery charging/discharging application. A laboratory prototype is developed for the verification of analytical results.