A newly developed screening current simulation method for REBCO pancake coils based on extension of PEEC model

Abstract

Since the screening current (SC) in rare earth-barium-copper-oxide (REBCO) coated conductor (CC) generates an undesired magnetic field, it must be accurately estimated, especially for magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR). Moreover, in recent years, it was pointed out that the screening current enhanced the stress/strain in REBCO CC, when an REBCO magnet was operated as an insert under an ultrahigh magnetic field. The previously reported SC simulation methods may be roughly categorized into finite element method (FEM) and equivalent circuit method. The FEM-based method often adopted an axisymmetric model or a thin film approximation model, while the circuit-based are the simple equivalent circuit model and the network equivalent circuit model, so-called the partial element equivalent circuit model. The latter is newly proposed in this paper. Features of those SC simulation models are briefly compared to each other in this paper. Each SC simulation models have pros & cons. We have to adequately chose an SC simulation model depending on a purpose. In addition, we propose a new developed SC simulation model, named the advanced partial element equivalent circuit (A-PEEC) model. It is extendable to an SC simulation of no-insulation REBCO pancake coils. To simulate the SC of a simple coil model and the LBC3 magnet, we investigated the screening current distribution maps, and the simulated screening current-induced fields were compared with the measurements. We have confirmed the validity of the newly proposed A-PEEC model.

Plastic Deformation Simulation of REBCO Tapes Using Particle Methods

“…2. A 3-D Partial Element Equivalent Circuit (PEEC) method is adopted for the electromagnetic simulation [15]. The PEEC method enables to simulate an accurate screening current with short computation time.…”

Investigation into accuracy of turn-to-turn contact resistance measurement in low-frequency AC method by 3D numerical simulation

“…Figure 2 shows the 3D PEEC model, which has been developed to simulate the screening current [39]. In the 3D model, the REBCO pancake coils are subdivided in not only the radial and azimuthal directions but also the tape-transverse direction.…”

Fast and accurate electromagnetic modeling of non-insulated and metal-insulated REBCO magnets

“…Although the effect of screening currents has been widely studied in insulated HTS windings, both by two-dimensional (2D) cross-sectional models [21][22][23][24][25][26][27][28][29][30][31][32] and 3D models [33][34][35][36], there are few studies for NI or MI magnets. A highly remarkable work about screening currents in HTS inserts is the 3D modelling of [37]. Although 3D modelling can potentially describe all features of this geometry, such as low-criticalcurrent section in a particular turn, 3D modelling is computationally expensive.…”