Nine-phase Permanent Magnet motor drive system for ultra high-speed elevator

In this paper, a 9-phase permanent magnet (PM) synchronous motor drive system based on multiple 3-phase conventional drive systems has been proposed. A 9-phase motor has been developed as a traction motor for a world record ultra high speed elevator. The simplified mathematical model, which can be incorporated with 3-phase current controller, has been derived. The feasibility and the validity of the proposed drive system have been demonstrated by experimental results of the scaled version of a prototype 9-phase motor.