30kW, 200V/900V LCL IGBT DC/DC converter prototype design and testing

This paper details design, development and testing a 30kW, 200V/900V inductor-capacitor-inductor (LCL) DC/DC converter prototype. The converter topology benefits from fault tolerance capability from either side which is of extreme importance for developing future DC grids and DC micro grids. The converter comprises two active full bridges based on insulated gate bipolar transistors (IGBTs) and can achieve high stepping ratios with no internal ac transformer. An internal LCL circuit is used to provide voltage stepping and fault tolerance property. A specific pulse with modulation (PWM) technique is presented which facilitates implementation of gate signals generation on a TI microcontroller (MCU). Simulation and experimental results are presented to demonstrate the converter performance in step up and down modes at full power, feeding to a passive resistive load and DC fault isolation from either side.