Analytical calculation of the flux density distribution in a superconducting reluctance machine with HTS bulks rotor

Abstract

This paper deals with the analytical computation of the magnetic field distribution in a wholly superconducting reluctance motor. The rotor is made with high temperature superconductor bulks which nearly present a diamagnetic behavior under zero-field cooling. The stator consists of superconducting armature windings fed by AC currents of high amplitude. The superconducting stator winding can generate a high rotating magnetic field without the need of ferromagnetic material in the rotor. The electromagnetic torque is obtained by the interaction between the rotating magnetic field created by the superconducting stator windings and the variable reluctance due to the superconducting bulks. The proposed analytical method is based on the resolution of Laplace's equation (by the separation of variables method) for each sub-domain, i.e. rotor shaft, holes between superconducting bulks and air-gap. The global solution is obtained using boundary and continuity conditions. Magnetic field distribution and electromagnetic torque obtained by the analytical method are compared with those obtained from finite element analyses.

Analytical Model for the Magnetic Field Distribution in a Flux Modulation Superconducting Machine

“…(0, ) is finite Hz (28) From (27) and 28, the boundary conditions can be rewritten in terms of the magnetic scalar potential in order to find the eigenvalue of the problem in the r-direction.…”

“…This is not a problem for the studied machine because the reluctance torque is very low due to its large air-gap. However, this should be considered in a machine with a thinner air-gap [28].…”

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

“…Following a sensitivity analysis, it was noted that the magnitude of the trapped magnetic flux density upon increasing the n-values was decreasing until no significant changes could be observed. Indeed, according to (2) and neglecting the numerical terms and the normal-state resistivity ρ nsc , as the n-value gets larger and larger, the electrical conductivity becomes independent of n, and…”

Analysis of a Surface-Mounted Permanent-Magnet Machine with Overhang Structure by Using a Novel Equivalent Magnetic Circuit Model

“…It can calculate parameters and performances of electric machines with high accuracy [1-5, 8, 13, 15, 19-21, 27, 28, 30]. Also, this method can be used for analyzing practical electrical machines with the geometric complexity, such as synchronous reluctance motors [15], switched reluctance machines (SRM) [27], SPM machines [2,4,5,30], slotless motors [19,20], and PM actuator [13,21]. The second method is an equivalent magnetic circuit model (EMCM).…”