A flux pump is a device that can inject DC current into a superconducting circuit without any electrical contact — effectively serving as a wireless excitation source.
It works by using a moving magnetic field (such as a rotating or travelling-wave field) to induce and “pump” magnetic flux into a closed superconducting loop, which in turn generates a steady DC current.
In superconducting motors, the flux pump replaces traditional current leads or brush-type exciters.
As a result, the excitation current can be delivered to the superconducting rotor without metal connections between the room-temperature power supply and the cryogenic superconducting coil
Conventional power source excites HTS magnets
Main advantages:
1.High power supply stability, high output accuracy.
Relative disadvantages:
1. Large size.
2. Serious heat loss at the joint.
3. Cost disadvantage.
Flux pump excites HTS magnets
1.A noncontact excitation method.
a)No welding head is used，which can reduce heat leakage loss.
b)Flux pumps allow HTS magnets to operate in quasi-persistent mode.
2. Small size. Reduce system volume requirements.
3. Low cost. Beneficial to reduce excitation cost, such as portable MRI scanner.
Experimental Setup
Experimental setup of HTS flux pump excitation for superconducting generator – demonstrating wireless DC current injection
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