Pulsed Charging Circuit for Lightweight Superconducting Magnet Excitation

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Solution Overview

Problem

Existing superconducting magnet excitation power supplies are bulky, heavy, and suffer from significant heat leakage through current leads, limiting their efficiency and portability.

Innovation Solution

A charging and field supplement circuit utilizing a capacitor charging and discharging circuit, superconducting magnetic energy storage, and a superconducting persistent-current switch, which employs a pulsed current to minimize the size and heat leakage of the power supply, using a low-current, high-voltage power source and high-resistance current leads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional excitation power supplies are used for superconducting magnets, then the magnets can be charged and maintained, but the power supplies are heavy and bulky with serious heat leakage through current leads

Engineering Contradiction:
Improveheat leakageVSAvoidpower supply weight
Core Design Contradiction:
Loss of energyVSWeight of moving object

Solution Approach 1:

The patent employs periodic pulsed current charging instead of continuous current supply. The capacitor charges during off-periods and discharges pulsed current during on-periods to charge the superconducting magnet. This periodic action allows the use of high-resistance current leads that would otherwise overheat under continuous current, thereby reducing heat leakage while enabling a lighter power supply design.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the electrical parameters by using high-resistance current leads combined with pulsed current operation. The high resistance would normally cause excessive heat, but the pulsed nature of the current reduces the average power dissipation (P=I²Rt), allowing the use of simpler, lighter current leads with higher resistance that still achieve the required charging function with reduced heat leakage.

Inventive Principle:
Principle #35Parameter changes

2Power

If traditional excitation power supplies are used for superconducting magnets, then the magnets can be charged and maintained, but the power supplies are heavy and bulky

Engineering Contradiction:
Improvecharging capabilityVSAvoidpower supply weight
Core Design Contradiction:
PowerVSWeight of stationary object

Solution Approach 1:

The patent uses periodic pulsed current charging where the capacitor accumulates energy and then releases it in pulses to charge the superconducting magnet. This allows the power supply to deliver high peak power during pulses while maintaining a lightweight design, as the average power requirement is much lower than continuous supply systems.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The capacitor performs preliminary energy storage before the actual charging pulse is delivered to the superconducting magnet. This preliminary action allows the use of a smaller, lighter power supply that charges the capacitor gradually, then uses the stored energy for the high-power charging pulse, eliminating the need for heavy continuous power supply equipment.

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If high-resistance current leads are used to reduce heat leakage, then energy loss is reduced, but the power supply size and weight are reduced further

Engineering Contradiction:
Improveheat leakageVSAvoidpower supply volume
Core Design Contradiction:
Loss of energyVSVolume of stationary object

Solution Approach 1:

The periodic pulsed current operation enables the use of high-resistance current leads by reducing the duty cycle. The leads only carry high current during brief pulses rather than continuously, allowing the use of thinner, smaller leads with higher resistance that still keep heat leakage acceptable while reducing the overall power supply volume.

Inventive Principle:
Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The circuit significantly reduces the volume and weight of the power supply while minimizing heat leakage, enabling a lightweight and portable excitation power supply for superconducting magnets.

Implementation Method 1

an energy-storage capacitor; a capacitor charging circuit; a capacitor discharging circuit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the energy-storage capacitor and the capacitor discharging circuit are used to charge the superconducting magnet in a pulsed current manner

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a superconducting persistent-current switch; a superconducting magnetic energy storage circuit

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentEP4191818B1Charging and field supplement circuit for superconducting magnets based on pulsed current
Publication Date: 2025.10.15 SHANGHAI JIAOTONG UNIV
  • EP4191818B1 patent drawingFigure 1
  • EP4191818B1 patent drawing

AI summary

A charging and field supplement circuit for superconducting magnets based on a pulsed current includes a capacitor charging circuit, an energy-storage capacitor, a capacitor discharging circuit, a superconducting magnetic energy storage circuit, and a superconducting persistent-current switch. Two output ends of the capacitor charging circuit are respectively connected to two ends of the energy-storage capacitor. Two input ends of the capacitor discharging circuit are respectively connected to the two ends of the energy-storage capacitor. Two output ends of the capacitor discharging circuit are respectively connected to two input ends of the superconducting magnetic energy storage circuit. Two output ends of the superconducting magnetic energy storage circuit are respectively connected to two input ends of the superconducting persistent-current switch. Two output ends of the superconducting persistent-current switch are configured to charge and magnetize a target superconducting magnet.