Key Research Areas

HSHT – High-Speed-Hybrid-Turbo

Power generation from exhaust gas to electrify the turbocharging as well as to electrically support the power train is an innovative approach to meeting stricter CO₂ regulations through electric hybridisation. For this purpose, a generator-turbine and an engine-compressor system for highest speeds have been developed. A generator is used to produce electricity from the exhaust gas of the combustion engine. An electric motor drives a supercharger compressor for autonomous charging of the combustion engine. The generator, driven by exhaust gas turbines, can generate more electricity from the exhaust gas than the electric motor needs to drive the supercharger. In electrohybrid combustion engines, this surplus electricity can be fed into the battery to support the power train and drive auxiliary electrical units (e.g. water pump, air conditioning compressor).

Other applications of the developed electric high-speed compressor are highly efficient charging compressors for fuel cell vehicles or compressed air generation.

The converter developed by Fraunhofer IZM uses GaN semiconductors to enable the highest motor and generator speeds of 180,000 rpm with up to 15 kW power on a 400 V battery system. The bidirectional inverter is controlled via CAN bus or USB. The control supports the use of a speed control or a power setting according to the electrical load conditions.