Concept design of a high power superconducting generator for future hybrid-electric aircraft

Abstract

The reduction of emission is a key goals for the aviation industry. One enabling technology to achieve this goal, could be the transition from conventional gas turbines to hybrid-electric drive trains. However, the requirements concerning weight and efficiency that come from applications like short range aircraft are significantly higher than what state-of-the-art technology can offer. A key technology that potentially allows to achieve the necessary power and volume densities for rotating electric machines is superconductivity. In this paper we present the concept of a high power density generator that matches the speed of typical airborne turbines in its power class. The design is based on studies that cover topology selection and further electromagnetic, HTS, thermal, structural and cryogenics aspects. All domains were analyzed by means of analytical sizing and 2D/3D FEA modeling. With the help of our digital twin that is a synthesis of these models, we can demonstrate for the first time that under realistic assumptions on material properties gravimetric power densities beyond 20 kW kg−1 can be achieved.

Perspectives and Development of Electrical Systems in More Electric Aircraft

“…With the discovery of high-temperature superconductors in 1986 [163,164], the work in the field of electric propulsion gained speed. Many HTS engine designs and tests have been performed [165][166][167][168][169][170]. The advantages of HTS motors are low weight, compact size, very high power densities, and negligible DC loss; however, AC loss of HTS winding must be minimised [168].…”

“…Contrary, the open-loop system is lighter and needs only cryogenic liquid, so it can be applied also to small aircraft [169]. In [170], hydrogen at 20 K is proposed as the cooling liquid for HTS generator with effective power 10 MW, power density 20 kW kg −1 , line voltage 3 kV, and coils' current density 300 A mm −2 .…”

4-MW Class High-Power-Density Generator for Future Hybrid-Electric Aircraft

“…In terms of high power electrical machines, one of the largest developments is reported in [11], where some preliminary results of a Mark#1 2.5 MW permanent magnet generator are promising. There is a series of publications recently presented that investigate various topologies - [12], [13], and concepts - [14], [15] of electrical machines that could be considered as candidates for propulsion system of future hybrid-electric aircraft. Taking into account the technology readiness and high requirements for efficiency, power density and reliability, electrical machines with permanent magnets (PM) are a promising topology to fit the criteria for hybrid-electric propulsion systems [16], [17].…”

Review on the Use of Superconducting Bulks for Magnetic Screening in Electrical Machines for Aircraft Applications

“…Several topologies of HTS synchronous machines are considered promising such as rotor-wound machines [15,16]; superconducting "permanent magnet" machines, made from HTS bulks [17] or HTS stacks of tapes [18]; and flux modulation machines [19][20][21][22][23]. The last topology, as illustrated in Figure 1 in its axial flux version, is composed by a static solenoid coil made of superconducting tapes which produce a DC magnetic field.…”