Highly efficient and compact single phase PV inverter with GaN transistors at 250 kHz switching frequency
The application of Gallium Nitride (GaN) power transistors in a single phase inverter for photovoltaic (PV) systems is presented inverter. The power of the system is 2 kW. For both stages (DC boost stage and inverter stage), a very high switching frequency of 250 kHz is used. By this, a highly compact design for the inverter (200 x 150 x 80 mm3 / 2.4 l) was reached. The power to weight ratio corresponds to 1.2 kW/kg and the power to volume ratio to 0.85 kW/l. Despite the high switching frequency, a maximum efficiency of 98% is reached. Compared to state of the art PV inverters, the size of the developed inverter was reduced by a factor of 5 while still maintaining a similar or even higher efficiency by means of an about 10 times higher switching frequency which is made possible with the use of GaN transistors.