Abstract：A novel fixed switching frequency active-clamp forward dual resonant converter with regulation capacity of output voltage is proposed in this paper. Different from the traditional active-clamp technique, single active-clamp circuit in the converter demagnetizes two transformers to simplify the circuit structure, and also serves as another resonant tank for energy transmission. Meanwhile, The series-input structure distributes the input voltage, hence the switch voltage stress is reduced significantly. The interleaved PWM control strategy adopted in the proposed converter can reduce the input current ripple, and the implementation problems in the traditional frequency modulation, such as synchronous rectifier driving logic or magnetic components optimization can be avoided. Additionally, with the resonance principle, soft-switching can be achieved for the primary switches and the diodes. Thus, there is no reverse recovery loss in the diodes, which improves the efficiency. The operating principles is discussed in detail in this paper. Finally, a prototype sample with 43~53V input and 24V/1.8A output is implemented and the experimental results verify the correction of the theoretical analysis.
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2018, Vol. 33 
