A ZCS Isolated Full-Bridge Boost Converter with Multiple Inputs

A modular-based, zero-current-switched (ZCS), isolated full-bridge boost converter with multiple inputs is presented. By connecting a simple auxiliary circuit, between the full-bridge input and the input choke, in each module, the transformer leakage inductance and output capacitance of the switching devices are used to create a quasi-resonant path for facilitating ZCS of all full-bridge switching devices. The operation of the auxiliary circuit integrates into the FB circuit and each auxiliary circuit operates independently among the modules. Thus, the operation of the multiple-input structure will not be affected by the newly added auxiliary circuits, but, at the same time, all switches become zero-current-switched. A 290 W prototype with two input voltages of 5 V and 12 V has been tested and built. Theoretical predictions are verified with the experimental measurement results. The effectiveness of the proposed auxiliary circuit on improving the conversion efficiency is studied.