A Novel Three-Output Port Isolated DC-DC Converter with Four Switches Providing High Gain Quadratic Non-Inverting Buck-Boost or Derived Boost Characteristics Along with Continuous Input Battery Current Operation

A novel four-switch three-port isolated Direct Current (DC)-Direct Current (DC) high gain converter derived from the modified Input Parallel Output Series (IPOS) cascaded connection of input boost and buck-boost converters and output flyback converter is portrayed in this paper. In the continuous Conduction Mode (CCM), this converter can provide a quadratic non-inverting buck-boost characteristic or a derived boost characteristic at the isolated output port using two distinct switching combinations and utilizing the turns ratio N offered by the High-Frequency Transformer (HFT). Two non-isolated output ports characterize a boost and a non-inverting buck-boost output respectively. The boost inductor at the battery-interfacing input side renders a continuous current operation from the battery, allowing increased battery life and integration possibility to Distributed Energy Resources (DER) like a Photovoltaic (PV) array. CCM analysis of the ideal converter in the steady-state is documented in detail and the voltage gains are penned down. MATLAB® SIMULINK platform is used to simulate the converter and its results validate the proposed operation. Closed-loop current controller is designed and its efficacy is validated using step changes in load.