A Novel Six-Switch Isolated DC-DC Converter with an Isolated Port Providing DC Transformer Gain and Two Non-Isolated Ports Serving Reciprocal Non-Inverting Buck-Boost Voltage Gain for EV Applications

This paper proposes a novel isolated DC-DC converter with six switches comprising one isolated port subscribing to pure DC transformer action and two non-isolated ports with reciprocal non-inverting buck-boost operation. The Continuous Conduction Mode (CCM) voltage gain at the isolated output port is reliant only on the secondary-to-primary turns ratio <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$N$</tex> of the High-Frequency Transformer (HFT) and not on the per unit duty cycle of the converter, hence providing a pure DC transformer action. The two non-isolated output ports are complimentary to each other and provide buck-boost characteristics with CCM voltage gain at the ports as mathematically inverse in magnitude to each other. Detailed steady-state CCM analyses are portrayed and MATLAB® SIMULINK simulation waveforms are presented. Closed-loop current controller is designed and its efficacy is tested using step changes in load.