| 摘要 |
<p>A superconducting switch controller, or a control method, suitable for a superconducting switch 4 connected across a superconducting magnet 2, comprises: a modulated power supply connected to a heater which is controlled such that it is heated to maintain the switch temperature within a predetermined temperature range above the superconducting critical temperature when providing a resistive current path. The controller may modulate the power provided to the heater in accordance with the heat generated in the switch 4 by a change in the magnetic field of the superconducting magnet 2. This heat may be evaluated through a thermal sensor on the switch, the use of previously recorded modelled behaviours or through some other evaluation techniques, to optimize the temperature control of the switch 4. The controller may be integral with the direct current power source 1 of the heater. The heater control may be implemented by a computer with real-time or selected algorithm or PID control operation. The control arrangement may be used during the ramping of a superconducting magnet for NMR or MRI, where the switch has a weak thermal link to the cryogenic cooling system of the magnet.</p> |
