This paper presents a comprehensive study of a current-fed full-bridge boost dc–dc converter with zero-current switching (ZCS), based on the constant on-time control for high voltage applications. The current-fed full-bridge boost converter can achieve ZCS by utilizing the leakage inductance and parasitic capacitance as the resonant tank. In order to achieve ZCS under a wide load range and with various input voltages, the turn-on time of the boost converter is kept constant, and the output voltage is regulated via frequency modulation. The steady-state analysis and the ZCS operation conditions under various load and input voltage conditions are discussed. Finally, a laboratory prototype converter with a 22–27-V input voltage and 1-kV/1-kW output is implemented to verify the performance. The experimental results show that the converter can achieve high output voltage gains, and the highest efficiency of the converter is 92% at full-load condition with an input voltage of 27 V.
- Current fed
- High voltage
- Zero-current switching (ZCS)
Fig. 1. Conventional full-bridge ZCS PWM converter circuit.
EXPECTED SIMULATION RESULTS:
Fig. 2. Experimental waveforms of VO at a full-load condition.
Fig. 3. Experimental waveforms of Vgs1, Vgs2, VAB, and iLk at (a) full-load
condition and (b) 20%-load condition.
Fig. 4. Switching waveforms of Vgs1, Vds1, and iS1 at (a) full-load condition
and (b) 20%-load condition.
This paper has presented a study of the current-fed full bridge boost converter with ZCS, based on the constant on-time control for high-voltage dc–dc applications. The turn-on time of the full-bridge boost converter is designed as a constant in order to achieve ZCS, and the output voltage is regulated by varying the switching frequency. The parasitic components of the high-voltage transformer can also be incorporated with the resonant tank for ZCS operation. The steady-state analysis and the ZCS operation conditions are also discussed in this paper. By carefully designing the circuit parameters, the converter can be operated with ZCS at various load and input-voltage conditions. Furthermore, the presented converter can achieve high efficiency and high output voltage gain.
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