Silicon has been used as a semiconductor material in power devices for many decades. The material properties of Silicon have reached its maximum theoretical limit. For power devices, wide band gap materials such as Silicon carbide (SiC) and Gallium Nitride (GaN) are promising due to their superior material properties, such as higher switching speed and lower switching Figure of Merit (FOM). The lower device loss in GaN devices reduces the heat sink requirement, thus makes the converter more compact in size, which potentially makes them cheap.
The objectives of this research project include:
- analytical and optimal application of GaN devices in dc-dc a converter
- designing of high efficiency magnetics (transformer and inductor)
- power loss modelling of dc-dc converter
- development of a compact high power bi-directional GaN converter
Figure 1. Hardware prototype of a 1.7 kW bidirectional GaN converter
(a)
(b)
Figure 2. Measured efficiency curve of the bidirectional dc-dc converter (a). boost mode, (b). buck mode
Publications:
1. R. Ramachandran, M. Nymand, N. H. Petersen, “Design of a compact, ultra -high efficient isolated DC-DC converter utilizing GaN devices,” 40th Annual Conference of the IEEE Industrial Electronics Society, IECON 2014, Nov 2014
2. R. Ramachandran, M. Nymand, “Design and Analysis of an Ultra-High Efficiency Phase Shifted Full Bridge GaN Converter,” Applied Power Electronics Conference and Exposition, 30th Annual APEC Conference Proceedings 2015, Mar 2015
3. R. Ramachandran, M. Nymand, “Analysis of Capacitive Losses in GaN Devices for an Isolated Full Bridge DC-DC Converter,” International Conf. on Power Electronics and Drive Systems, PEDS, June 2015
4. R. Ramachandran, M. Nymand, “Switching losses in a 1.7 kW GaN based full-bridge DC-DC converter with synchronous rectification,” 2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe), Sept 2015
5. R. Ramachandran, M. Nymand, “A 98.8% Efficient Bidirectional Full-Bridge Isolated DC-DC GaN Converter,” Applied Power Electronics Conference and Exposition, 31th Annual APEC Conference Proceedings 2016, Mar 2016
Contact Person
Morten Nymand
Associate Professor
University of Southern Denmark
Email: mny@mmmi.sdu.dk