Input-parallel output-series cascading possibilities of single-switch galvanically isolated quasi-Z-source DC-DC converters

Focus is on a transformer based single-switch galvanically isolated quasi-Z-source converter. Single-switch topologies suit well for low power applications due to low complexity and cost of realization. However, their performance is rather limited, since only one switch should handle all converter power. Input-parallel output-series (IPOS) cascading improves stress of semiconductor devices, reliability, input current ripple, efficiency and DC voltage gain in a wide range of the input voltage, while maintaining the duty cycle of the switches within a reasonable range. The proposed two different approaches for IPOS cascading are analyzed and compared with the reference single-switch topology. Theoretical results are supported with a simulation study using PSIM software including Thermal Module for semiconductor power losses analysis.