Dual Phase Shift Modulated 2-HB-LLC Resonant Converter With Hybrid Rectifier for Ultra Wide Output Voltage Range Applications

Deep depletion electric vehicle battery packs have a very large voltage range. The ultra wide voltage range makes the optimal design of LLC converter extremely difficult. In this paper, an improved dual-phase-shifted 2-HB-LLC staggered resonant topology is proposed, which uses a pair of back-to-back active switches on the secondary side to meet the ultra-wide voltage range of electric vehicle battery packs. The switching frequency of the proposed converter is identical to the resonant frequency. Moreover, the special secondary structure with dual phase shift control strategy achieves high boost ratio, effectively reducing the number of turns and size of the transformer. Therefore, the converter has excellent voltage regulation characteristics while maintaining high efficiency. A 3kW converter prototype is designed to generate an ultra-wide output voltage of 5-500 V from a 380V DC input voltage. The peak efficiency of the prototype is 97.4%, and the voltage is well regulated. The experimental results are in agreement with the theoretical analysis.