University of Stuttgart: Hybrid Propulsion System for the e-Genius plane

The electric plane “e-Genius” developed and built by the University of Stuttgart will be equipped with a highly efficient hybrid drive as part of a new research project. This makes it possible to integrate the new, low-resistance shape of the specially developed electric plane with features such as fast fueling and a long flight range, which are achieved by means of an additional combustion engine and a generator. The aim of the research project is to develop a particularly efficient plane with a fuel consumption of less than 3.0 liters per 100 km at a traveling speed of 170 km/h.

The relatively complex propulsion system consisting of an electric motor, batteries, a generator, and a combustion engine, must not put more stress on the pilot than existing systems. Therefore, the team is developing a “one-lever” control: The pilot specifies the desired propulsion for the propeller and a dSPACE MicroAutoBox autonomously decides whether to use battery energy or start the combustion engine. The battery system acts not only as an energy storage system but also as a buffer for the difference between the power demand of the propulsion motor and the power generated by the combustion engine. This makes it possible to operate the hybrid electric plane in different ways.

Current research at the University of Stuttgart focuses on optimized operation modes to lower fuel consumption and prolong battery life. The developed algorithms can be tested early by means of simulation in MATLAB®/Simulink® and then be transferred directly to dSPACE MicroAutoBox. The MicroAutoBox installed in e-Genius can be used to test the algorithms in the real plane. In addition, it can be used to test functions ensuring that the new plane is suitable for everyday use. For example, a “look-ahead” function will be implemented that lets the pilot specify the state of charge the battery should have when the plane lands. This way, it is possible to land the plane with a certain state of charge. This can be necessary to perform a purely battery-driven start and lift-off right after landing. The dSPACE MicroAutoBox fully automatically ensures that the desired state of charge is achieved.

Ingmar Geiss, Deputy Project Manager e-Genius, University of Stuttgart, Germany