Combined magnetic levitation and propulsion: The mag-transit concept

Mag-Transit is a unique combination of magnetic levitation and propulsion for people mover applications. Linear induction motors are used for levitation, propulsion, braking, and guidance. Since there are a minimum of moving parts there is a potential for a substantial increase in system reliability and availability as compared to conventional systems. Modern solid-state technology provides the capability to condition sufficient quantities of electrical energy to control motor excitation, and thereby levitation, within a closed-loop servo system. Real time measurements of air gaps and vehicle accelerations are used to compute the desired levitation force. In addition, the solid-state electronics provides the ability to control independently the speed of the vehicle by a continuously variable excitation frequency to the motors. An overview is provided of the Mag-Transit concept from a control system standpoint. Results from a dynamic simulation of a test vehicle configuration are presented.