# Optimal Design of High-Critical-Current SMES Magnets: From Single to Multi-Solenoid Configurations

## TL;DR

This paper introduces a new design framework for high-current superconducting magnets to improve energy storage and grid stability.

## Contribution

An integrated design framework combining magnetic field modeling, anisotropy characterization, and adaptive optimization for SMES magnets.

## Key findings

- A single solenoid achieved a 22.6% increase in critical current and 41.8% increase in energy storage.
- A 20-unit array reached 0.15 H/827 A (20 MJ) with coordinated gap adjustment.
- The framework supports efficient design and deployment of large-scale HTS magnets in smart grids.

## Abstract

Advanced energy storage solutions are required to mitigate grid destabilization caused by high-penetration renewable energy integration. Superconducting Magnetic Energy Storage (SMES) offers ultrafast response (<1 ms), high efficiency (>95%), and almost unlimited cycling life. However, its commercialization is hindered by the complex modeling of critical current with anisotropic behaviors and the computational inefficiency of high-dimensional optimization for megajoule (MJ)-class magnets. This paper proposes an integrated design framework synergizing a two-dimensional axisymmetric magnetic field model based on Conway’s current-sheet theory, a critical current anisotropy characterization model, and an adaptive genetic algorithm (AGA). A superconducting magnet optimization model incorporating co-calculation of electromagnetic parameters is established. A dual-module chromosome encoding strategy (discrete gap index + nonlinear increment) and parallel acceleration techniques were developed. This approach achieved efficient optimization of MJ-class magnets. For a single solenoid, the critical current increased by 22.6% (915 A) and energy storage capacity grew by 41.8% (1.12 MJ). A 20-unit array optimized by coordinated gap adjustment achieved a matched inductance/current of 0.15 H/827 A (20 MJ), which can enhance transient stability control capability in smart grids. The proposed method provides a computationally efficient design paradigm and user-friendly teaching software tool for high-current SMES magnets, supporting the development of large-scale High-Temperature Superconducting (HTS) magnets, promoting the deployment of large-scale HTS magnets in smart grids and high-field applications.