This paper proposes a current-fed isolated bidirectional DC-DC converter (CF-IBDC) which has the advantages of wide input voltage range, low input current ripple, low conduction losses, and soft switching over the full operating range. Compared with conventional CF-IBDCs, the voltage spikes of the low-voltage (LV) side switches in the proposed converter can be eliminated without additional clamp circuits. The converter adopts the pulse width modulation (PWM) plus hybrid phase-shift control scheme such that the bus voltage can match the output voltage by means of the transformer. Thus, the current stresses and conduction losses of the converter become lower. In addition, the practical ZVS of the secondary-side switches can be realized by adjusting the phase-shift angle within the secondary side when in light load or no load condition. The operating principles and characteristics including the power transfer, Root-Mean-Square (RMS) current, and soft switching are investigated in detail. Then the design guidelines of inductors are also given. Finally an experimental prototype with 30-60V input and 400V/2.5A output is built to verify the correctness of theoretical analyses.
- Current-fed bidirectional isolated dc–dc converter
- Pulse width modulation (PWM) plus hybrid phase-shift control
- Practical ZVS
- Wide input voltage range