International Conference on Control, Automation and Systems 2010 Oct. 27-30, 2010 in KINTEX, Gyeonggi-do, Korea Zero-Power Control of Magnetic Levitation Vehicles with Permanent Magnets Chang-Hyun Kim 1 , Han-Wook Cho 2 , Jong-Min Lee 1 , Hyung-Suk Han 1 , Bong-Seup Kim 1 , and Dong-Sung Kim 1 1 Department of Magnetic Levitation and Linear Drive Korea Institute of Machinery and Materials, Deajeon, Korea (Tel : +82-42-868-7279; E-mail: chkim78@kimm.re.kr) 2 Department of Electric, Electronic & Communication Engineering Education Chungnam National University, Deajeon, Korea (Tel : +82-42-821-8581; E-mail: hwcho@cnu.ac.kr) Abstract: This paper deals with the zero-power control of magnetic levitation (maglev) vehicles that use permanent magnets as well as electromagnets for levitation. The nominal load is levitated by permanent magnet and the current consumption for stable levitation can be reduced. In order to guarantee the tracking capability, the proposed controller is based on the state feedback controller and modified to balance attraction force and total weight. The commanded voltage is used instead of the coil current in the feedback loop so that the current measurement can be avoided. A full-scale hybrid maglev tester was constructed and some experiments were carried out to show the performance of the proposed method. Keywords: Magnetic levitation, Permanent magnet, Electromagnetic suspension, Power minimization. 1. INTRODUCTION A maglev vehicle is an environment-friendly trans- portation system which reduces noise, vibration and wear induced from the friction, and makes no pollution. As for the levitation, an attractive-electromagnetic suspen- sion (EMS) is one of the most popular method and sev- eral maglev vehicles (UTM-01 and UTM-02) were al- ready developed using EMS in Korea. However, an EMS system has power consumption and heating problems be- cause a continuous current should be supplied to maintain a desired airgap. Permanent magnets (PMs) were used along with elec- tromagnets (EMs) in order to reduce power consumption [1]-[7]. Total weight is levitated by PMs, and EMs are controlled to deal with weight variation and external dis- turbance. Power is mainly consumed during the transient period, and thus the temperature increase of the coil can be minimized. Another advantage of hybrid maglev is the reduction of additional electronic components because of the use of the smaller EMs. In this paper, zero-power control of hybrid maglev ve- hicles is proposed. The proposed controller is based on the state feedback controller and modified to implement zero-power control. The measurement of the coil current is not necessary in the proposed controller. The control characteristics are compared with simulation studies. The performance of the proposed controller is verified with a full-scale hybrid maglev tester. 2. HYBRID MAGLEV TESTER AND ITS MODELING A hybrid magnetic levitation system was tentatively chosen to be used for a high speed maglev vehicle after rigorous studies. In this system, propulsion force is gen- erated by long-stator linear synchronous motor (LSM). The basic configuration of the hybrid levitation and LSM Fig. 1 The design of an hybrid maglev and propulsion system. Fig. 2 The hybrid maglev tester. propulsion is shown in Fig. 1. The hybrid levitation and propulsion devices are composed of a laminated rail/translator side core structure, high-performance PMs, and control current windings without cooling systems. The upper long stator is located along the guideway on the ground, and the lower hybrid magnets are attached to the vehicle. On the vehicle, most power is consumed by the levitation system, and the required power is much smaller that propulsion power. Linear generator windings are used to generate the necessary power on the vehicle. To examine the feasibility of hybrid maglev, a full- scale hybrid maglev tester depicted in Fig. 2 was con- structed. This tester corresponds to one third of a maglev bogie and important design specification is listed in ta- ble 1. Some design considerations of the hybrid maglev 978-89-93215-02-1 98560/10/$15 ©ICROS 732