DC-DC converter with a wide load range and a wide input-voltage range

This thesis investigated the possibility of increasing the efficiency of a DC-DC converter over a wide load range and a wide input-voltage range based on the Single Active Bridge (SAB) topology with two approaches. The first approach involved making changes to the topology whereas the second made use of the concept of modularity. In the first approach, two changes were made to the Single Active Bridge topology. The first approach resulted in a new topology termed as the Partial Resonant Single Active Bridge (PR-SAB), and the second approach involved adding a switchable snubber capacitor to the SAB. In the second approach with modularity, the topology changes were applied to the Input-Parallel-Output-Parallel (IPOP) converter with SAB modules. Significant efficiency improvements were achieved over a wide load range with the optimisation of the SAB module snubber capacitors. Efficiency improvement over a wide input voltage range was achieved with the Input-Series-Output-Parallel (ISOP) converter. Various module shutdown methods were investigated in this thesis which enabled this improvement.