Research on Position Detecting Method for High

2014 년도 한국철도학회 춘계학술대회 논문집
KSR2014S190
Research on Position Detecting Method for High-Speed Train with Coreless
Linear Synchronous Motor
손연*†, 이창영*, 한영재*
Yan Sun*†, Chang Young Lee*, Young Jae Han*
Abstract One successful application of coreless LSM (Linear Synchronous Motor) is Japanese Maglev
system at the Yamanashi Test Line. Position detection of Yamanashi Test Line was realized by inductive
radio system which consists of onboard receiving antenna and cross inductive cable. By analyzing amplitude
and phase variation of inductive electromotive force from receiving antenna, position and speed information
could be determined. However, coreless LSM is proposed for wheel-on-rail system in this paper not for
suspension system. We are going to introduce a novel SM (Superconducting Magnet) coreless LSM, which
will provide propulsion force for wheel-on-rail high speed train. Inductive cross-loop cable could also be
applied for this proposed system, but considerations should be taken due to effects of tracks and complicated
electromagnetic field.
Keywords : Coreless LSM, Position detecting method, high speed train
1. Introduction
Construction and maintenance cost is a big issue for high speed maglev train. So some researchers are
showing interests to develop a hybrid system combining advantages of both conventional wheel-on-rail
system and Maglev propulsion system. This hybrid type system is based on wheel-rail method, but it
enables to overcome the speed limitation by adhesion because it is operated by a non-contact method
using a linear motor as a propulsion system and reduce the overall construction costs by its compatibility
with the conventional railway systems. A novel SM (Superconducting Magnet) coreless LSM (Linear
Synchronous Motor) system, which will provide propulsion force for wheel-on-rail high speed train is
proposed. Design models of coreless-typed LSM with various distributed and concentrated windings for
600 km/h very high speed train were discussed [1]. As an indispensable subsystem, position detection
system is very important for operation control of this hybrid system, because traction system of high
speed train needs precise location and speed information to carry out the operation tasks with safety and
reliability. This paper will focus on position detecting method for high speed train with coreless LSM.
The rest of this paper is organized as follows, section 2 will introduce positioning method for transrapid
and our proposed hybrid system, in section 3, considerations of positioning method for hybrid system are
discussed, and conclusions are made in the final part.
†교신저자: 과학기술연합대학원대학교 철도시스템공학([email protected])
* 한국철도기술연구원, 초고속자기부상철도연구단
2. Positioning method for transrapid and hybrid system
Many researches have been done to study positioning method for Germany suspension systemTransrapid. To get precise position data, absolute positioning and relative positioning are required.
Relative positioning is used to get high-accuracy position data and absolute positioning is used to
eliminate cumulated errors from relative position signals. Both absolute positioning and relative
positioning are needed for coreless LSM propelled hybrid rail-on-wheel system, however hybrid system
need different positioning method from tranrapid due to different configurations.
2.1 Positioing method for transrapid
2.1.1 Absolute positioning: location reference flag reading [2]
(a) Location reference flags on guideway
(b) Location reference flag with binary code “1011”
Fig. 1 Location reference flag of Transrapid
(a) Hardware structure of the reference flag-reader
(b) Layout of the transmitting/receiving coils
Fig.2 Location reference flag-reader
2.1.2 Relative positioning: long stator tooth-slot reading [3]
Fig.3 Transrapid configuration
(a) Sensor configuration and coil arrangement
(b) Signal processing principle
Fig.4 Long stator tooth-slot reader
2.2 Positioning method for hybrid system
ERTMS/ECTS (European Rail Traffic Management System/European Train Control System) is the
standard for rail traffic control. Eurobalises implemented on the track acting as positioning markers, and
odometer estimates the train position. Each Eurobalise shall transit information securely between the track
and on-board system. Eurobalise only communicates with train when the train passes over it, and it is also
used for resetting odometer [4]. Eurobalises realized absolute positioning and odometer realized relative
positioning according to the standard.
Fig.5 Position system based on inductive loop cable [5]
Considering compatibility with conventional rail-on-wheel train, Eurobalise is also applicable for
hybrid system. Relative positioning can refer to Japanese Maglev train positioning system, which consists
of inductive cross loop cable and onboard antenna. Inductive loop cable with fixed shape is laid along the
rails and receiving antenna is installed at the bottom of the train. High frequency alternating current is
injected into cross cable as excitation, and magnetic field with opposite direction is produced by adjacent
rings. According to Faraday’s law of electromagnetic induction, an inductive electromotive force is
produced between both ends of the coils. When the train operates along the rail, speed and position
information can be determined by amplitude and phase change of inductive electromotive force [5].
3. Considerations of positioning method for hybrid system
Compared with Japanese maglev system, proposed hybrid system has different configurations.
Propulsion coils of Japan system are installed on both sides of the U shaped track and inductive loop
cable is laid on the track surface, while LSM coil used for propulsion is installed on the track. So, we
need to consider complicated magnetic field around track. Metal sleepers and metal bogie would affect
magnetic field so as to affect electromotive force used to derive position information. Simulation is done
to verify magnetic flux density changes due to existence of metal materials.
Fig.6 Hybrid system configuration [1]
For any kind of material, both magnetization and eddy current effects exist. Compared with the vacuum
magnetic field distribution, the first major impact is an enhancement of the spatial magnetic field, while
the second is to weaken it. In addition, the eddy current effect is related with the frequency of the
magnetic field [5]. Aluminum, stainless steel and iron bulks are taken as metal sleepers to make
simulation under the same conditions.
Table 1 Property of metal materials
Metal Materials
Relative Permeability
Conductivity (s/m)
Aluminum
1.000021
3.8x107
Stainless Steel
1
1.1 x106
Iron
4000
1.03 x107
Equivalent model of inductive loop coil is shown in Fig.7 (a), and 3D simulation model is made to
according to equivalent loop coil.
(a) Equivalent model of inductive loop coil [5]
(b) Simulation model with coil and metal bulk
Fig.7 Simulation model
Magnetic flux density along coil extension line affected by different metal material is shown in Fig.8.
Due to high permeability, iron bulk enhanced magnetic field distribution, while eddy current effect of
aluminum and stainless steel bulk weaken the magnetic field distribution. So we need to design a
receiving coil that can get less effect because of metal bulks. Future study will discuss coil design.
XY Plot 1
0.0025
Maxwell3DDesign4
XY Plot 1
ANSOFT
0.0030
Curve Info
Maxwell3DDesign3
ANSOFT
Curve Inf o
Mag_B
Setup1 : LastAdaptive
Freq='2MHz' Phase='0deg'
Mag_B
Setup1 : LastAdaptive
Freq='2MHz' Phase='0deg'
0.0025
0.0020
0.0020
Mag_B
Mag_B
0.0015
0.0015
0.0010
0.0010
0.0005
0.0005
0.0000
0.00
0.25
0.50
0.75
Distance [meter]
1.00
1.25
1.50
0.0000
0.00
0.25
0.50
(a) No metal bulk
1.00
1.25
1.50
(b) Iron bulk
XY Plot 1
0.0030
0.75
Distance [m eter]
Maxwell3DDesign3
ANSOFT
XY Plot 1
0.0030
Maxwell3DDesign3
ANSOFT
Curve Info
Curve Info
Mag_B
Setup1 : LastAdaptive
Freq='2MHz' Phase='0deg'
Mag_B
Setup1 : LastAdaptive
Freq='2MHz' Phase='0deg'
0.0025
0.0025
0.0020
Mag_B
Mag_B
0.0020
0.0015
0.0015
0.0010
0.0010
0.0005
0.0005
0.0000
0.00
0.25
0.50
0.75
Distance [meter]
1.00
1.25
1.50
0.0000
0.00
(c) Aluminum bulk
0.25
0.50
0.75
Dis tance [meter]
1.00
1.25
1.50
(d) Stainless steel bulk
Fig.8 Magnetic field affected by different metal materials
4. Conclusions
Position detection method is discussed for hybrid coreless LSM system in this paper. According to system
analysis and comparison with high speed maglev of transrapid and Japanese maglev system, eurobalise is a
good candidate for absolute detection and inductive loop cable is applicable for relative detection. Due to
complicated magnetic field, metal bulks around positioning system would affect magnetic field distribution
so as to affect electromotive force used to derive position information. Simulation verified considerations of
metal bulks and future study will design receiving coil that get less effect by metal bulks.
References
[1] C.B. Park, J.H. Lee, B.S. Lee, J.H. Kim, S.K. Lee, S.M. Jung and H.W. Lee (2013) A Study on the
Structure of Linear Synchronous Motor for 600km/h Very High Speed Train, Proceedings-International
Symposium on Linear Drives for Industry Applications.
[2] Cunyuan Qian, Zhengzhi Han and Weida Xie (2007) Research on Absolute positioning system for
high-speed maglev train, Proceedings of the 2007 IEEE International Conference on Mechatronics and
Automation, pp.922-926
[3] Song Xue *, Zhiqiang Long, Ning He and Wensen Chang (2012) A high precision position sensor
design and its signal processing algorithm for maglev train, Sensors, pp.5225-5245
[4] Dhahbi, S, Abbas-Turki, A. ; Hayat, S. ; El Moudni, A. (2011) Study of the high-speed trains
positioning system: European signaling system ERTMS/ETCS, 2011 4th International Conference on
Logistics (LOGISTIQUA), pp. 468-473
[5] Dai C1, Dou F, Song X, Long Z.(2012) Analysis and design of a speed and position system for maglev
vehicles, Sensors, pp.8526-8543

Download Report