The Fraunhofer Institute for Solar Energy Systems ISE in Germany has set a new world record of 99.03 % efficiency for inverters used in solar energy systems.
Inverters convert the DC current generated by a solar power system into AC current, suitable for use in a home and for feeding directly into the mains electricity grid.
By using new components and improving the circuit technology, the researchers have further reduced losses from their own previous best result by a further third.
The higher the inverter efficiency, the higher the system yield. For a 30 kW system, an efficiency value which is 1 % higher results in an additional yield over ten years of 3000 kWh.
Much of the improvement is credited to junction field-effect transistors (JFETs) made of silicon carbide (SiC). In addition, the researchers optimised the gate units and many other details of the circuit.
The higher efficiency also means lower thermal losses, allowing for smaller cooling devices and a more compact construction, offsetting some of the cost of utilising the more expensive technology.
Prof. Bruno Burger, leader of the Power Electronics Group at Fraunhofer ISE, sees enormous potential for the new silicon carbide transistors as they are constantly becoming more refined and increasingly economical.
SiC transistors are superior to the conventional IGBTs of silicon (Si) used commonly today, particularly for higher reverse voltages. The main reasons are the breakdown field strength, which is ten times higher for SiC than Si, and the band gap, which is three times larger for SiC than Si.
Related: Learn more about inverters
