Session: 01-12 Electrified Propulsion and Novel Cycles II

Paper Number: 154127

High Voltage Turboelectric Testbed Design, Integration, and Performance 

This paper presents the experimental results of a representative turbo-electric aircraft operating at a system voltage of 550-V. Hybrid turbo-electric power systems operating at high voltages increase overall system effectiveness through increased power to weight ratios by virtue of their decreased $I^2 R$ losses. This affords such aircraft design flexibility as more overall weight and space can be allocated to energy sources. The test rig into which this electrical system was outfitted has been used to analyze system performance in previous work. However, the previous electrical configuration operated at a voltage undesirable for use with an engine capable of outputting 180-kW. The system discussed in this paper was constructed to achieve two objectives: demonstrate the transient and steady state loads induced on a turbine engine through electric loading, and to highlight the considerations necessary to create a high voltage system. These objectives were accomplished through the fabrication of a turbo-electric ground vehicle comprised of a modified Cessna-172 aircraft, a modified PBS-TP100 turboprop, a variable-resistance load, and a purpose-built powertrain. The electrical system is supplied exclusively from a generator coupled to the turboprop through a pulley system, devoid of any supplementation in the form of batteries or capacitance. A test matrix was devised in which the turboprop was incrementally stepped through fixed throttle positions at which the system was placed under varying electric loads. Engine operation data was acquired including output shaft torque, speed of the free and gas turbines, and combustion gas temperature, while voltage, current, and power data was recorded at different locations within the electrical systems. Observations from this study highlight the importance of capacitance to hybrid powertrains, the forces induced on turbine engines by electric load, and functional safety considerations in the design and operation of hybrid systems.

Presenting Author: Joshua Drake Oklahoma State University

Presenting Author Biography: Joshua Drake is an electrical engineer working for Oklahoma Aerospace Institute for Research and Education and finishing a master's degree in electrical engineering. He has spent three years working in industry writing embedded software and developing electrified vehicles for the underground construction industry while contributing to turbo-electric research with Oklahoma State University.

Authors:

Joshua Drake Oklahoma State University
Joshua Johnsen Oklahoma State University
Joshua Melvin Oklahoma State University
Ryan Paul Oklahoma State University
Kurt Rouser Oklahoma State University
Nathan Wisniewski Oklahoma State University