Research On Isolated Half Bridge VRM Topology With Low Voltage High Current Output

The power eletronics system integration(PESI) has received more and more attention in the recent years,in this dissertation the isolated low voltage high current VRM topologies will be investigated.Isolated circuits Include: active clamp forward(ACF),push pull forward,half bridge(symmetrical half bridge SHB and duty cycle shifted half bridge DCSHB) etc.The main point will mainly focus on the SHB topology,especially on analysing some methods to improve the performance of SHB,such as restraining the resonance of primary side of tranformer,soft switching control schemes and gate driving of the synchronous recitifiers etc..Analysis of the small signal modeling of SHB is given ,also with the loss calculation of the circuit.Experimental comparison between ACF,push pull forward,HSHB,DSCHB is carried on and 1V/30A prototype is obtained for each proposed topology,there will be two prototypes with different synchronous driving schemes for ACF.The experimental results varify the theoretical analysis of each proposed circuts.