WIRIC – Wide Range Isolated Converters

Power electronics applications are continuously growing in general and more applications require or benefit from ability to handle larger voltage variation on primary and/or secondary side. Universal input AC/DC converters are one such example where the DC link voltage may vary three times dependent on where the converter is used.



Half and Full Bridge converters are popular for power converters in the kW range due to its good transformer utilization and high performance. There also exists DC-DC converters of half- and full-bridge types can normally withstand a input voltage variation a factor two with maintained efficiency. Many applications would benefit if the input voltage variation could be relaxed. One important applications is regeneration breaking with supercapacitors as energy storage element. In contrast to battery storage the terminal voltage highly depends on the stored energy and for efficient usage the converter needs to maintain high efficiency over a larger voltage range.

In this project a concept based on a configurable transformer will be developed, manufactured and evaluated in a real application. A proof of concept have been performed by simulation in LT-spice where it have been shown that the input voltage range can be extended to four and beyond depending on the transformer and switch configuration.

  • A transformer and rectifier module will be designed where most of the converter losses will be localized.

  • Advantages integrating the primary switches into the same module will also be studied.

  • A full converter of the concept will be designed and manufactured and characterized. The converter will be evaluated as replacement for an existing converter in a real application and pros and cons will be evaluated.


The project aims at performing research in wide range DC/DC converters, investigation of different technologies and developing of at least two prototypes for such applications. The project spans from topologies, transformer design, simulations, converter design and characterization and is divided into four work packages.

The project is performed at Mid Sweden University in the research group Power Electronics in collaboration with the industrial Partners Powerbox, SAAB and Elektronikkonsult. The industrial partners are all active in power electronics ranging from design, products for power electronics and system level integration of power converters.


Research group


Project leader
Associate Professor Kent Bertilsson
+46 10 142 89 15

Mats Wårdemark,
Powerbox AB

Stefan Linders,

Vidar Wernö,

Project period

2017-05-01 – 2020-04-30


7 827 850 SEK (3 899 850 SEK from the Knowledge Foundation and 3 928 000 SEK from companies)