Thermal analysis for the HTS stator consisting of HTS armature windings and an iron core for a 2.5 kW HTS generator

Abstract

Most present demonstrations of high-temperature superconducting (HTS) synchronous motors/generators are partially superconducting, only installing HTS coils on the rotor as excitation windings. The possible applicability of HTS armature windings is an interesting research topic because these windings can certainly increase the power density attributed to a potentially high armature loading capacity. In this study, we analysed the thermal behaviours of a developed 2.5 kW–300 rpm synchronous generator prototype that consists of an HTS stator with Bi-2223–Ag armature windings on an iron core and a permanent magnet (PM) rotor. The entire HTS stator, including the iron core, is cooled with liquid nitrogen through conduction cooling. The rated frequency is set at 10 Hz to reduce AC loss. The properties of the HTS windings and the iron core are characterized, and the temperatures in the HTS stator under different operation conditions are measured. The estimated iron loss is 11.5 W under operation in 10 Hz at liquid nitrogen temperature. Conduction cooling through the silicon iron core is sufficient to cool the iron core and to compensate for the temperature increment caused by iron loss. The stable running capacity is limited to 1.6 kW when the armature current is 12.6 A (effective values) due to the increasing temperature in the slots as a result of the AC loss in the HTS coils. The thermal contact between the HTS coils and the cooling media should be improved in the future to take away the heat generated by AC loss.

Optimization for preparing Bi1.68Pb0.32Sr1.75Ca1.85Cu2.85O10+y powders by wet ball milling

“…(Bi, Pb) 2 Sr 2 Ca 2 Cu 3 O 10+y (Bi-2223) high temperature superconductor (HTSC) has a great potential for a variety of applications such as power transmission cables [1,2], superconducting magnets [3,4], motors [5,6], generators [7,8], transformers [9,10], current limiters [11,12] and current leads [13,14]. This is because the first generation of the Bi-2223 superconducting tapes can carry a sufficiently high transport critical current density, J c , and can be mass produced with a rather low price compared with the second generation of the superconducting tapes [15].…”

Future of Electrical Aircraft Energy Power Systems: An Architecture Review

“…However, superconducting architectures still present several drawbacks and challenges. For instance, to achieve superconductive materials a cryogenic cooling system is required impacting size, weight, efficiency and specific power [37]- [39]. In addition, due to the novelty there is no clarity when it comes to the operation of such devices at high altitude.…”

No-Insulation High-Temperature Superconductor Winding Technique for Electrical Aircraft Propulsion

“…The application of HTS windings on rotor can significantly increase the magnetic field at air gap, so that the power density of the machine is increased. In synchronous machines, rotation speed of fundamental fields generated by stator windings is same with the rotation speed of rotor, thus the HTS rotor windings serve as a DC magnet during operations [29][30][31].…”