Simultaneous control of propulsion and levitation of linear induction motor in a novel Maglev system

Abstract

Magnetically levitated transportation systems are used in various fields, for example in the clean room, because they have unique merits such as being contactless. The usual system has the levitation system, such as electrical magnets and drive system and a linear motor, respectively. In this system we should control the levitation in considering the attractive force caused by the drive system because the linear motor used as the drive system has not only the thrust force but also the attractive force changing the condition of the electrical power source. Then in this paper, we propose a novel transportation system without the electrical magnet for the levitation system. In this system, there is only the linear induction motor as the drive system and we use the attractive force of the motor for the levitation. We propose a novel method to control the levitation and the drive simultaneously. We use a new power source combined with the high frequency component and the low frequency one. At first, we show the basic characteristics of the linear induction motor used as the drive system and explain the concept of the proposed control method. Secondly we show the characteristics of the motor powered by the combined power supply. Next we explain the control scheme. Finally we show the results of the levitation controlled by the proposed method.