Cree MOSFETs claim solar power record
The most efficient electrical inverters yet for linking photovoltaic systems to the power grid have been made by the Fraunhofer Institute for Solar Energy Systems, using Cree SiC technology.
The MOSFET-based inverters operate at a maximum efficiency of 98.5 percent and dissipate 30 to 50 percent less waste energy than rival silicon transistors, which operate at less than 98 percent efficiency.
The effectiveness of the prototype Cree devices is even more impressive as Fraunhofer ISE says that this is the first time SiC transistors have ever been tested for this application "“ although combinations of SiC diodes and thyristors have been used before (see related story).
The inverters convert the solar cell s direct current output into alternating current that is hooked up to public electricity grids. A good inverter needs to retain high efficiency over a wide range of power levels, and again Cree's SiC components set a new precedent in this regard.
The significance of this performance level is enhanced by German feed-in tariffs for solar power, which pay â‚¬0.45 ($0.66) for each kWh generated.
“This is approximately five times higher than the electricity costs for the industry,” explained Bruno Berger, project leader of the testing program.
“If we increase the efficiency of a 5 kW inverter by 1 percent, each year we feed an extra 50 kWh into the grid and gain â‚¬22.”