Control strategies for Maglev electromagnetic suspension bogies

Two electromagnetic suspensions have been successfully realised for low speed Maglev operation: the High Speed Surface Transport (HSST) Maglevs, and the GEC-Alsthom Birmingham Maglev which operated from 1984 until 1995. The two design strategies are quite different. The former, designed initially for high speed (>200 km/h), employs a magnetic primary and an air spring secondary suspension enabling higher speed operation with satisfactory ride quality and canting. The latter uses a single stage magnetic suspension which provides the necessary ride quality without moving parts but its speed is limited to about 140km/h by the allowable in airgap deflection (<5mm RMS). In this paper the vertical primary suspension of the HSST type of suspension is analysed and the potential of incorporating aspects of the Birmingham control strategy are examined