Linear Carrier System with Self-Sensing Magnetic Suspension Tracks

A magnetically suspended linear carrier system is developed which has tracks composed of electromagnets for suspension. The electromagnets are operated in the self-sensing mode to omit gap sensors along the tracks. Permanent magnets for power saving are built in the carrier so that the number of permanent magnets is reduced, compared to systems with permanent magnets in the stator. A new combined permanent and electromagnet is developed for the coil currents to overcome only the air-gap reluctance primarily. The magnetic and electrical circuits of the developed hybrid magnet are analyzed to show that the observer-based self-sensing suspension method can be applied. The self-sensing suspension is realized and the virtually zero power suspension is automatically accomplished.