Research On Phase Shift Full Bridge DC/DC Converter With Current-Doubler Rectifier

As the fast development of modem electrical and electronics technology and thedevice of power electronics, the development trend of modern electronic products ishigh frequency, miniaturization and light weighted, and soft-switching technology isone of the main means.A 1kW DC/DC converter is developed with phase-shift and current-doublerrectifier applied. In the primary side of the transformer, a blocking capacitor and asaturable inductor are used. In the converter, zero voltage and zero current switching(ZVZCS) in the full-bridge power switches and the soft-switching of the rectifierdiodes are achieved. The leading-leg operating in zero voltage on over wide loadrange; and zero current off without circulating current loss is achieved for thelagging-leg. In the secondary side of the transformer, current-doubler rectifier, twodiodes turned off naturally, and two output inductors connected in an interleaving way,which makes the current ripple significantly reduced, and decreases the size ofinductors. Therefore, the size and weight of the system can be decreased significantly.Current and voltage double closed-loop control strategy is applied to theconverter, in which current loop is inside and voltage loop is outside. Peak currentcontrol strategy is used in the current loop. The current loop can be considered as aproportional element, the order of whole system can be reduced as an inertial element,which makes the controller designing easier.The experimental result is given in the last part of the thesis, the converter worksin good performance, all the power switches achieved in operating in soft-switchingcondition, the turn-on and turn-off loss is reduced significantly, the EMC (Electromagnetic compatibility) is improved, a satisfying result is obtained.