A High-Gain DC-DC Converter with a Wide Range of Output Voltage

In fuel-cell-powered electric vehicles, the output characteristics of the fuel cell are relatively soft, and the output voltage is unstable. Therefore, a DC-DC converter is required between the fuel cell and the inverter to transform the output voltage of the fuel cell into a suitable voltage for the motor drive. Existing non-isolated DC-DC converters cannot meet the requirements of high voltage gain, high efficiency and a wide range of output voltage simultaneously. To improve these performances, a high-gain DC-DC converter with a wide range of output voltage, based on a switched capacitor structure, is proposed in this paper. The converter supplies power to the load by connecting multiple capacitors with the input source in series in switch-on states, while the input source charges the capacitors through a series connection with an inductor in switch-off states. In comparison to existing converters, the proposed converter maintains high voltage gain at lower duty ratios and offers a wide range of output voltage. The operating principles, key waveforms and parameter design of the topology in Continuous Conduction Mode (CCM) are described and analyzed in detail, and the voltage gain of the proposed converter is compared with some other DC-DC converters. Finally, the results of simulations using Simulink and hardware experiments that were conducted to validate the theoretical analysis are described.

Automated summary

In fuel-cell-powered electric vehicles, a DC-DC converter is required to transform the unstable output voltage of the fuel cell into a suitable voltage for the motor drive. Existing converters cannot meet the requirements of high voltage gain, high efficiency, and a wide range of output voltage simultaneously. To address this, a high-gain DC-DC converter based on a switched capacitor structure is proposed in this paper, offering a wide range of output voltage and maintaining high voltage gain at lower duty ratios. The operating principles, key waveforms, and parameter design of the proposed converter are described and analyzed, and simulation and hardware experiments validate the theoretical analysis.