Method and apparatus for use of alternating current in primary suspension magnets for electrodynamic guidance with superconducting fields

摘要

An electrodynamic suspension system levitates a platform or a transportation vehicle by an array of onboard superconducting electromagnetic coils forming a primary member overlying a secondary member on the guideway in a transverse flux orientation with respect to a plane of levitation of the moveable member above the secondary member on the guideway. The superconducting coils are energized by alternating current to produce an alternating field of magnetic flux. The frequency of the alternating current is selectable down to direct current. The frequency is selected to cause the vehicle to be levitated statically above the guideway. Once levitated the frequency is reduced as the speed of the vehicle increases along the guideway usually not in excess of 60 miles per hour. Passive electrically conductive plates form the secondary member to respond to the alternating field of magnetic flux and both guide and levitate the vehicle by inherently-stable repulsive induction action to maintain a controllable spaced relation between the guideway and the vehicle.