Design, analysis and test results for a superconducting linear synchronous motor

A linear synchronous motor has been designed to propel a 480 km/h magnetically levitated passenger vehicle. The paper describes the motor and presents the results of tests which have been performed on essentially full-scale components of the motor using a 7.6 m-diameter test-wheel facility. Controlled starting, acceleration, cruising, deceleration and transient operation have been demonstrated. A 6-component force balance has been used to measure the three forces and three moments acting on a single stationary superconducting magnet due to its interaction with the split 3-phase windings mounted on the rim of the test wheel and energised by a variabl-efrequency current-controlled inverter power supply. Measured forces and terminal characteristics over complete cycles of force angle are in excellent agreement with analysis based on a coupled circuit model of the machine and mutual inductance computations. Moments were measured to be small underall operating conditions. Two modes of control have been demonstrated. The ¿-scheme, proposed for a full-scale system, maintains the angle between induced voltage and phase current at a value which optimises the motor characteristics, i.e. inverter MVA rating, etc. ß-control, which may be required for starting, uses vehicle position detectors to fire the inverter thyristors at appropriate times.