Compact bidirectional DC/DC converter

Purpose and goal

The project´s goal was to design a demonstrator of compact and efficient converter operating at higher switching frequency than commercial products. The project shows that it is possible to construct a compact transformer with good efficiency. A converters have been designed and have been characterized up to 900W with the losses in the transformer is well below those in the schottky diodes. Based on measurements, simulations and calculations estimated a converter efficiency of 95% is realistic to achieve with a volume of over one liter.

Results and expected effects

A demonstrator to a very compact design of the transformer has been designed and constructed. The synchronous rectification is not working satisfactorily and with schottky diodes the secondary losses are too extensive. Further development will be done to remedy these deficiencies. The module will be further development by integrating the switching elements and EMI-reducing measures to develop a prototype that can be evaluated in a commercial application.

Approach and implementation

The relatively short period of time did not allow the possibility of revising the design but demanded that everything would work flawlessly the first attempt. A bit into the project, a decision was made to redesign the transformer with a construction that would be smaller with better efficiency and allow a greater voltage variation. This has affected the project negatively as all targets have not been met and a complete converter has not been evaluated for more than 900W. However, in the long run, it was a good decision as SEPS developed a more competitive technology.