Design and Initial Testing of a High-Speed 45-kW Switched Reluctance Drive for Aerospace Application

Abstract

Abstract-This paper presents innovative research towards the development of a 45 kW high speed switched reluctance drive as an alternative starter-generator for future aero-engines. To perform such a function the machine had to be designed with a very wide constant power-speed range. During enginestart/motoring mode, a peak torque demand of 54 Nm at 8 krpm was met, whilst in generating mode, 19.2-32 krpm, the machine was designed to deliver a constant power of 45 kW. The key enabling feature of the design lies in the novel rotor structure developed so as to allow for such a wide speed range. The results presented, are those measured during the initial testing phase and validate the system design and performance in the low-speed region with the machine operated in starting-mode. The measured machine power density is at 9.8 kW/ltr, whilst the global system efficiency is at 82%.

Design, Optimization and Initial Testing of a High-Speed 5-Kw Permanent Magnet Generator for Aerospace Application

“…Similar solutions are described in the works of Ganev [20,21]. Thus, the energy density of the highpower aviation HSPM has already reached very good results [18][19][20][21]. However, at the same time, the HSPM energy density of small and medium power decreases with the power decreasing, even with a significant increase in the rotor rotational speed and in the cooling efficiency.…”

“…For example, Borg Bartolo et al describe starter-generators with these parameters [18]. Siemens describes an electrical motor for aerospace applications with a 0.15 kg/kW power density [19].…”

“…Figure 1 shows the obtained curve, which characterizes the decrease in the power density and efficiency as a power change function. The curve is based on the analysis of promising developments and industrially produced HSPM of the aviation systems [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Figure 1 shows that the minimum achieved energy density of commercial high-speed SG of the UAVs is 0.32-0.33 kg/kW at the power below 5 kW.…”

“…In conditions of difficult heat removal from the rotor, these losses can lead to overheating of permanent magnets and failure of the entire SG. In [10][11][12][13][14][15][16][17][18][19][20][21][22], to determine the losses in permanent magnets, their crushing in the axial direction is used. The preliminary calculations show that the loss reduction is approximately 150-200% by crushing the permanent magnets from the one sector length of 50 mm to the one sector axial length of 5 mm.…”

Technology, Research and Applications of Switched Reluctance Drives

“…A wide overview can be found in [134]. Especially aircraft starter-generators and fuel pumps in the range of several ten kW have already been investigated by many working groups [135]. Another focus is the automotive industry searching for magnet-free traction drive alternatives for the roll out of millions of electric cars [136].…”