Dual-working-modes-based negative output wide voltage gain range DC-DC converter with low input current ripple for fuel cells

A dual-working-modes-based negative output wide voltage-gain range DC-DC converter with low input current ripple is proposed in this paper. On the input voltage side, two Boost structures are connected in parallel, and the input current is split through two inductors, thereby reducing the volume of the inductors and improving the efficiency of the converter. When charging inductor, construct a higher charging voltage to increase the voltage gain of the converter. On the output voltage side, capacitors are discharged in series to further increase the voltage gain of the converter and reduce the voltage stress of the power semiconductors. The converter operates in synchronous mode when the duty cycle is less than or equal to 0.5, and in complementary mode when the duty cycle is greater than 0.5. The voltage gain in both modes can achieve smooth switching when the duty cycle is 0.5. By switching between different working modes, the voltage gain of the converter can be further improved and the input current ripple can be significantly reduced. The operating principle, characteristics, parameters design and comparison with other converters are analyzed. A 550W prototype is developed to verify the correctness of theoretical analysis.