| A theoretical investigation for a flux pump of high efficiency is presented. For this purpose, the current flow pattern in an idealized flux pump consisting of one superconducting strip and of a reciprocating magnet is analyzed and clarified.;Two phenomena observed in flux pumps, viz., the dropping characteristics for the output voltage as a function of the current and parasitic oscillations in the output voltage have been clarified. The voltage drop is due to the increase of the internal inductance of the pump with the current, while the occurrence of fluctuations is due to the switching of the load current from the front to the back of the normal spot.;It is concluded that a good pump design requires a low effective inductance and the prevention of critical current regions in the sheet. The novel flux pump suggested consists of a number of superconducting strips and pole faces of circular shape.;The current distribution on the superconducting sheet is derived by a computer simulation. The outcome of these computations shows that sharp corners in the pole face of the magnet are responsible for premature switching of the load current. From the configuration of the current one can also estimate the internal inductance of the superconducting sheet. |
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