Control of Starter Generator in a UAV with a Micro Jet Engine

A control method of a starter generator, which are for a jet engine for an unmanned aerial vehicle (UAV) system is proposed in this paper. Both the jet engine and the propellers that are powered by the jet engine via a starter generator generates the thrust power. Using the jet engine for obtaining the thrust, it is possible to extend a flight range since the energy density of the jet engine of the developed system is higher than the energy density of the battery in the conventional system. The miniaturization is also achieved by connecting the starter generator to the jet engine because high-frequency operation makes the starter generator compact. The proposed control strategy achieves the starting, powering, and cooling operations using the starter generator. Each operation is demonstrated with a 3-kW prototype. As the results, the maximum conversion efficiency of 92.7% is observed. Moreover, the minimum total harmonic distortion of the generator current is 16.5% at the rated operation speed (70000 r/min). Further, the exhaust nozzle temperature is stabilized within the maximum deviation of 2% of the command in a steady state.