Shape optimization by evolution strategy

In a magnet with pancake windings, inserting a gap between the pancake windings can increase the central magnetic field. This paper shows the optimized length of each gap is able to maximize the central magnetic field. Inserting a gap also improves field uniformity because the pancake windings are spread across a wider area. A high temperature superconducting (HTS) magnet consisting of BSCCO-2223 pancake windings was chosen for the calculation model to show the effectiveness of the proposed method. The relation was used to determine the critical current, and an evolution strategy was adopted for the optimization of gap length. The results of calculations show that the critical current and the central magnetic field increased by 86.0% and 33.7%, respectively, for a magnet consisting of ten pancake windings.

Section: Calculation Of the Critical Current And The Optimized Gapsmentioning

confidence: 99%

Properties of High Temperature Superconducting Magnet With Optimized Air Gap Between Pancake Windings

Kim

Cha

et al. 2011

“…Genetic algorithm, simulated annealing and evolution strategy are commonly used optimization technique. Among them, evolution strategy was adopted to calculate the critical currents of pancake windings because it was mathematically well defined and it provide relatively fast convergence [6]. In evolution strategy, child generation was generated from its parent generation by using random number.…”

Section: Determination Of Critical Currents Of Pancake Windingsmentioning

confidence: 99%

Design Method of a High Field HTS Magnet Consisting of Pancake Windings Having Different Current in Each Pancake Winding

Kang

Lee

Cha

et al. 2008

HTS pancake windings have been commonly used for the insert coil of high field magnets. All pancake windings have been connected in series and excited by a single power source. In that case, currents of the whole pancake windings were limited by the minimum current of the top and the bottom pancake windings where maximum perpendicular magnetic field was applied. This paper proposed the multiple power excitation of the HTS magnet which consists of pancake windings. It was able to increase the magnetic field of the magnet by conducting critical currents to all pancake windings. Results of calculation by using a model BSCCO magnet shows that proposed method was able to generate higher magnetic field comparing with the conventional single power excitation.Index Terms-HTS magnet, multiple power source, pancake winding, perpendicular magnetic field.

“…Evolution strategy is one of the non-deterministic optimization techniques [7]. Calculation procedure of winding currents was as follows.…”

Section: B Flow For the Calculation Of Critical Currentsmentioning

confidence: 99%

Current Estimation of an HTS BSCCO Magnet Having Multiple Power Sources Based on the Field Dependent $E{\hbox{–}}J$ Relation

Kang

Koo

Lee

et al. 2009

Due to the anisotropy of a tape-shaped HTS wire, the method to determine the operating current of an HTS magnet needs to be different from that of a LTS magnet. This paper presented estimation of the critical current of pancake windings excited by multiple power sources. Critical currents were determined by using field dependent -relation. A new method to define the magnetic field of the HTS wire has been proposed in this paper. Calculated critical currents of pancake windings were compared with measured ones of the HTS BSCCO magnet consisting of 10 pancake windings. Effects of multiple power excitation on the increment of the central magnetic field has been also described. Test results showed the estimated critical currents of pancake windings agreed well with that of measured ones and the central magnetic field was increased at multiple power excitation by 28.4% comparing with that of single power excitation.Index Terms--relation, HTS BSCCO magnet, multiple power excitation, pancake winding.