High output power reluctance electric motors with bulk high-temperature superconductor elements

Abstract

We present new types of electric machines with the rotors containing bulk high-temperature superconductor (HTS)—YBCO and Bi–Ag—elements. We discuss different schematics of hysteresis, reluctance, ‘trapped field’ and composed synchronous HTS machines. The two-dimensional mathematical models describing the processes in such types of HTS machines were developed on the basis of the theoretical analysis of the electrodynamic and hysteresis processes in the single-domain and polycrystal YBCO ceramic samples and plate shape Bi–Ag elements. We give the test results of the series of hysteresis, reluctance, ‘trapped field’ and composed with permanent magnets HTS motors with an output power rating of 0.1–18 kW and current frequencies 50 Hz and 400 Hz. These results show that in the media of liquid nitrogen the specific output power per one unit weight of the HTS motor is four to seven times better than for conventional electric machines. A comparison of the theoretical and experimental characteristics of the developed HTS motors show that they are in good agreement. We discuss the test results for a liquid nitrogen cryogenic pump system with a hysteresis 500 W HTS motor. We describe several designs of new HTS motors operating in the media of liquid nitrogen with an output power 125 kW (and more) and a power factor of more than 0.8. We discuss future applications of new types of HTS motors for aerospace technology, on-land industry and transport systems.

YBaCuO and REBaCuO HTS for Applications

“…designed, built, and tested a motor with extremely high power density and dynamics. As was suggested by Kovalev et al ., 34 HTS motors based on melt‐textured bulk YBaCuO monoliths can be operated in a synchronous regime, with HTS/ferromagnet composite rotors. From the various rotor designs, the “Zebra” type, which consists of a stack of ferromagnetic iron and YBaCuO segments (Fig.…”

“…The use of HTS components in rotating electrical machines , like motors and generators, will considerably reduce their weight and volume. Whereas tapes can best be used for rotor windings, bulk HTS monoliths were used for hysteresis motors, HTS‐trapped field motors but also HTS reluctance motors 34 . On the basis of an advanced reluctance principle, Oswald et al 35 .…”

Processing and Applications of Bulk RE–Ba–Cu–O Superconductors

“…It has also been suggested that the diamagnetic property of bulk superconductors can improve the efficiency and power factor of reluctance motors 47–49 . The concept for the bulk RE–Ba–Cu–O reluctance motor is to construct the rotor with a composite of ferromagnetic and bulk RE–Ba–Cu–O layers.…”

“…It has also been suggested that the diamagnetic property of bulk superconductors can improve the efficiency and power factor of reluctance motors. [47][48][49] The concept for the bulk RE-Ba-Cu-O reluctance motor is to construct the rotor with a composite of ferromagnetic and bulk RE-Ba-Cu-O layers. The composite configuration leads to a highly anisotropic ferromagnetic structure wherein magnetic flux experiences very low reluctance in one direction and very high reluctance in a perpendicular direction.…”

Comparison Between Modeling and Experimental Results of Magnetic Flux Trapped in YBCO Bulks

“…T ARGETING practical applications of High-Temperature Superconducting (HTS) bulks [1]- [3], a great deal of effort has been carried out regarding the art of growing materials, their properties and their modelling [4]- [7]. With regards to the latter, analytical formulae, in the simplest 2D cases using the Bean's Critical State Model (BCSM), and numerical models, in the most complex geometries involving 3D modelling techniques and/or more refined critical current dependencies, have been developed to predict the magnitude of the penetration field and the feasibility of trapping large magnetic fluxes [8]- [10].…”