Tunnel-Vision on Economic Linear Propulsion?

Abstract

Serious initiatives for high speed transport of vehicles/pods/capsules through evacuated tubes were presented in recent years. Most suggest magnetic levitation and linear motors of long-stator design, assuming passive pods. This paper takes a the different approach, yielding minimal energy use per distance per passenger and lowest initial cost. An active pod (short-stator) on wheels with an on-board battery, able to build up speed and regenerate effectively using an inexpensive passive track is proposed. In the stations, power is received from active track-coils to charge the on-board battery. Permanent magnet (PM) track sections enable thrust to speed-up and slow-down. A relatively small rotating induction motor on the wheels enables efficient coasting. Speeding up and slowing down with a linear motor at constant power is effective in terms of component utilization. A mere 100 W/kg (common in present commercial full electric cars) is sufficient to travel long distance at high speed on record low energy consumption (<10 Wh/km per passenger).