Evaluation of a non-isolated charger. Concept, analysis and reference design.

Sammanfattning: This report discusses the necessity of a galvanic isolation in an onboard charger for aPlug-in Hybrid Electric Vehicle. It was hypothesized that the galvanic isolation was asource of losses, and it is known that the use of galvanic isolation give rise to highercosts and it requires more space. Three different topologies without galvanic isolationwas investigated and simulated in OrCad PSpice. For these, cost, volume, weight andefficiency was analyzed and a best solution was chosen.It was found that using a bridgeless charger gave the highest efficiency, approximately98%, and it also had acceptable price and a satisfactory dimensional analysis. The bridgelesscharger did however not perform good regarding THD injected into the utility, thusfuture work with this charger is needed to investigate if it is possible to reduce the THDimpact without influencing the efficiency, size and weight to much. Synchronous rectificationwas also investigated and it was found that it was not a good solution in this case.