Multimode Variable Structure DC-DC Converter for Wide Input Voltage Range Applications

In this paper, the multimode variable structure isolated bridge converter for wide input voltage range applications has been presented, analyzed and tested. The primary side of proposed topology contains three pairs of bridge legs and two transformer windings. Meanwhile, the bridge rectifier and LC filter can be found in the secondary side of the converter. The proposed converter has the same advantages of the bridge converter such as high magnetic core utilization, low stray magnetic field, double basic switching frequency and low output ripple. Moreover, due to the particularity of multimode variable structure, the proposed converter can operate in three different modes to avoid extreme duty cycle and achieve high efficiency in the whole input voltage range. A 50V-300V input, 36V output and lkW prototype operating at 100kHz are implemented to verify expected performance. The experimental results show that the converter achieves high efficiencies in all input voltage range and excellent dynamic characteristic in all three operation modes.