Comparison of Si and GaN power devices used in PV module integrated converters

Using the newly developed enhancement-mode Galium-Nitride-on-Silicon (eGaN) devices with high conductivity and very fast switching speed a breakthrough in switching performance can be achieved. Multi-megahertz switching frequency capability will significantly reduce the size of passive components, adding the cost benefits and increasing the integration level and power density. As to date, the use of GaN devices in power converters is still in its infancy, but its widespread application is a near reality. PV converter industry is one of the areas which would greatly benefit from the new GaN technology. The most important requirements for a PV converter, efficiency and cost effectiveness, can both be addressed with improved switching devices. This paper presents a performance comparison of a PV module integrated DC-DC converter based on commercially available GaN and Si power devices. The presented results show that the first generation of GaN devices outperforms the best in class Si devices. Since GaN is immature technology, further improvements will be seen in the years to come.