Abstract：A novel unregulated isolated DC-DC converter,called as DC-DC Transformer(DCX),is proposed in this paper. DCX converter reflects the characteristics of the ideal transformer regardless of the voltage transfer ratio,the output load,switching frequency and duty cycle. The DCX converter composes of asymmetric half-bridge(AHB) with a DC-blocking capacitor at transformer primary side and series dual resonant circuit at the transformer secondary side. In proposed converter,magnetizing current is provided to achieve zero-voltage-switching(ZVS) turn-on for all switches. Meanwhile,Series-resonant circuit at second side of transformer is utilized to achieve zero current switching(ZCS) turn-off for the diodes and also eliminates the diode reverse recovery losses and voltage spike stress of diodes,while the voltage stress of diodes are clamp to output voltage. Comparing to the traditional AHB converter topology,the output diode voltage stress is reduced,and also the elimination of the filter inductance of the secondary side. Finally,through establish a 72W,48V input,12V output DC-DC converter prototype to verify the validity of the theoretical analysis.
[1] Ivensky G,Abramovitz A,Gulko M,Ben-Yaakov S. A resonant DC-DC transformer[J]. IEEE Transactions on Aerospace and Electronic Systems,1993,29(3): 926-934. [2] Xianjin Zhang,Caihong Fan. Research on a novel DC-DC transformer[C]. In proceeding of IEEE Electric Information and Control Engineering,2011: 1619- 1622. [3] Gonzalez M C,Alou P,et al. DC-DC transformer multiphase converter with transformer coupling for two-stage architecture[C]. Proceeding of IEEE Applied Power Electronics Conference,2010: 781-786. [4] Abramovitz A. Smedley K. A resonant DC-DC transformer with zero current ripple[C]. Proceeding of IEEE Power Electronics Specialist Conference (APEC),2005: 1299-1305. [5] Zhilei Yao,Lan Xiao,Yangguang Yan. A family of zero voltage switching DC-DC transformers[C]. Procee- ding of IEEE Applied Power Electronics Conference (APEC),2006: 513-516. [6] Weiyi Feng,Paolo Mattavelli,Fred C Lee. Pulse- width locked loop(PWLL) for automatic resonant frequency tracking in LLC DC-DC transformer (LLC- DCX)[J]. IEEE Transactions on Power Electronics,2013,28(4): 1862-1869. [7] Yuancheng Ren,Ming Xu,Julu Sun,et al. A family of high power density unregulated bus converters[J]. IEEE Transactions on Power Electronics,2005,20(5): 1045-1054. [8] Julu Sun,Ming Xu,Reusch D,et al. . High efficiency quasi-parallel voltage regulators[C]. In Proceeding of IEEE Applied Power Electronics Conference,2008: 811-817. [9] Ming Xu,Ya Liu,Julu Sun,Lee F C. Σ/sigma DC/DC conversion for computing and telecom applications [C]. Proceeding of IEEE Power Electronics Specialist Conference,2008: 1190-1195. [10] Pengjie Lai,Julu Sun,Lee F C. Control scheme and transient performance of sigma VR[C]. In Proceeding of IEEE Applied Power Electronics Conferenc,2010: 1927-1933. [11] Ejea J B,Ferreres A,Sanchis-Kilders E,et al. Optimized topology for high efficiency battery discharge regulator [J]. IEEE Transactions on Aerospace and Electronic Systems,2008,44(4): 1511-1521. （上接第65页） [12] Ki-Bum Park,Chong-Eun Kim,Gun-Woo Moon,et al. PWM resonant single-switch isolated converter[J]. IEEE Transactions on Power Electronics,2009,24(8): 1876-1886. [13] Jong-Jae Lee,Jung-Min Kwon,Eung-Ho Kim,et al. Dual series-resonant active-clamp converter[J]. IEEE Transactions on Industrial Electronics,2008,55(2)：699-710. [14] Yi-Hsin Leu,Chern-Lin Chen,Tso-Min Chen. Analysis and design for asymmetrical half-bridge forward mode converters[C]. Proceeding of IEEE Power Electronics and Drive Systems,2001: 126-130.
2014, Vol. 29 
