
Compact 3 kW on-board charger uses GaN transistors
Greater ranges and a denser network of powerful charging stations are urgently needed to increase the attractiveness of electric vehicles. Until then, on-board chargers will give electric cars the necessary independence, because practically every power socket can become a charging station. Due to the increasing storage size of the accumulators and the limited space available in the vehicles, however, conventional devices with silicon transistors are reaching their limits. Finepower has therefore developed an on-board charger (OBC) based on gallium nitride (GaN) which, at a power density of 3 kW/litre, exceeds the density of conventional chargers by 300%.
As a result, this water-cooled OBC measuring 210 x 50 x 60 mm (without housing) is extremely compact. It can convert input voltages from 85 to 264 VAC with a maximum power of 3,600 W to DC voltages from 200 to 450 VDC. The maximum output current is 10 ADC. Thanks to the innovative single-stage IBI-LLC topology, this happens at 230 VAC with an efficiency of 97%. With 115 VAC input voltage, the efficiency is still reaching 93%. Thanks to the excellent power factor of over 0.98, the nominal power of the supply can be skimmed off almost completely as active power.
Due to its DSP-based control technology, the OBC can be individually adapted to the respective operating conditions. Communication takes place via the standardized CAN bus. Up to three GaN chargers can be coupled together for three-phase supply, for example via three-phase sockets.
More information: https://www.finepower.com/en/
