Design of Multiphase Single-Switch Impedance-Source Converters

Focus is on the design of a multiphase galvanically isolated quasi-z-source dc-dc converter based on the single-switch topology. A novel control approach uses phase shedding for input-parallel-output-series architecture to achieve a wide input voltage regulation range. Current ripples are analyzed to implement the quasi-Z-source network with discrete and coupled inductors. Proposed approach provides for modeling of the latter taking into account leakage inductances of the coupled inductors and interactions between cells and the wiring inductance. An experimental prototype rated for 300 W, capable of delivering the rated power within the input voltage range of 10 V to 60 V was used. Experimental results demonstrate the performance of the developed concept implemented with resonant currents in the isolating transformer. Influence of the voltage-dependent resonant capacitance on the converter operation was analyzed.