A Study on the Loss in a Superconducting Magnet by the Control Current in a Hybrid Electro-Magnetic Suspension System

A proto-type hybrid electro-magnetic suspension system (hybrid EMS system) was developed by Yonsei university [1]. It is the first step of study on fundamental technology for advanced railroad system development. The proto-type hybrid EMS system consists of a ferromagnetic-core, a superconducting magnet (Bi-2223) for generating magneto-motive force (MMF) and a control coil for levitation control. This system has the characteristic of a control coil generating a magnetic flux to keep the levitation gap in constant value when the gap is attempted to be varied by external physical factors. In doing so, the induced current by the magnetic flux generate loss to the superconducting magnet inducing the possibility of an unstable system. Therefore, we have experimented and documented the results of evaluating the loss in the superconducting magnet generated by the control coil. This paper can be expected to suggest useful data for the design and operation of a hybrid EMS system.