Research and Design of New Permanent Magnetic Energy-Efficient Maglev Vehicle

This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/ACCESS.2019.2939879, IEEE Access

Research and Design of New Permanent Magnetic Energy-efficient Maglev Vehicle

Tao Gao 1, Jie Yang 1, Yongfang Deng1 ,Weihua Zhang 2, Zhenli Zhang 1 1School of Electrical Engineering and Automation, Jiangxi University of Science and Technology, Jiangxi Ganzhou 341000, China 2Southwest Jiaotong University National Laboratory for Rail Transit, Sichuan 610000, China *Correspondence: Tao Gao ([email protected]; Tel.: +86-797-8312585).

ABSTRACT In view of the current traffic criticism faced by urban construction and the quality development and personalized trend of future rail transit system, a new type of maglev rail transit system is proposed in this paper. The principles of the modules of train suspension guidance, linear drive and on-board communication are also introduced and analyzed in this paper. And the feasibility of train suspension structure is studied based on Ansoft Maxwell finite element simulation ,which includes: under three-dimensional magnetic field, the static magnetic force of Halbach permanent magnet array is changed, and the safety and reliability of the permanent magnet suspension array are verified by comparing with the actual test vehicle sampling data; The critical stability characteristics of suspension structure under static magnetic field are proved by physical modeling. Therefore, the electromagnetic damping structure is introduced into the vehicle suspension frame to constitute the hybrid suspension control system of permanent magnet electromagnetic, and the hybrid suspension model is established, which proves that the hybrid suspension system has controllable observability. Finally, the linearized state feedback control strategy is designed for the single-point electromagnetic levitation ball system to simulate the compensation and regulation of the static magnetic field by the electromagnetic damping system. The excellent performance of the electromagnetic levitation ball also proves the feasibility and rationality of the electromagnetic control strategy. Compared with the traditional electromagnetic hybrid suspension system, this system realizes "zero" power suspension, and the energy consumption of train suspension is only consumed in the instant that the electromagnetic damping system is regulated.

INDEX TERMS medium and low speed maglev train; Halbach permanent magnet array; suspended magnetic suspension system; urban rail transit system

I. INTRODUCTION this reduces the efficiency and liveability of the The problem of traffic congestion has been city. At the same time, with the development of criticized during the development of domestic small and medium-sized cities, traffic congestion cities. With Beijing, Shanghai and Guangzhou as has become more and more obvious. Following the typical large cities, the continuous growing the publication of the National New Urbanization scale of the cities leads to the increasingly Plan (2014-2020), the Central Urban Work significant contradiction between the Conference and the outline of the 13th Five-Year transportation demand of urban area and the Plan put forward a specific discussion on the transit capacity of the traditional ground construction of livable cities. After that, livable /underground transportation system, especially city construction becomes the important goal of the traffic congestion problem. To a large extent, our country's urban construction, and it is

This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/ACCESS.2019.2939879, IEEE Access

particularly urgent to upgrade and perfect the technology have also promoted the rapid urban public transportation system. development of sky train. A variety of suspended Urban rail transportation is considered to be rail transit systems have been put forward at home a green mode of transportation because of its large and abroad, such as the new energy suspension carrying capacity, safety, speed, energy and monorail train of CRRC Corporation Limited [1] resource saving character. Research shows that and the BYD straddle-type Sky Rail [2,3] in China, the energy consumption of rail transit is only 1/9 and the Israeli Sky Tran [4-6] and the Russian Sky of that of a car and 1/2 of a bus under the same Way rail cable car[7,8], Germany's Dortmund Air capacity. Therefore, it is a common understanding Rail [9], Japan’s Chiba Monorail [10], and so on. of the world to give priority to the development of Among these types of sky train, most of them still public transport system with rail transit as its use wheel-rail suspension and rotating motor backbone and use it as an important way to solve drive mode, while train is devoted to the urban traffic problems. At present, there are seven development of Personal Rapid Transit（PRT）, main types of urban rail transit systems at home introducing the advanced maglev technology, but and abroad, such as subway, light rail, monorail, the structure of it is complex. The processing of tram, maglev, etc.. The functional orientation and the support system is very difficult, so it is hard to technical advantages and disadvantages of these be applied widely. On the other hand, the systems are different, as shown in Table 1. The proposing of "zero" power control strategy [11,12] rail transit system like subway is mainly used to promotes the development and application of the solve the problem of large volume transportation electromagnetic permanent magnetic suspension and commuting, which has been developed hybrid structure and the electric permanent rapidly since the 12th Five-Year Plan. With the magnet hybrid suspension structure. At present, publication of "Opinions of the General Office of the Maglev Research Center of Shanghai Tongji the State Council on further strengthening University and National University of Defense management of urban rail transit planning and Technology has used permanent magnet array to construction", the blind construction on urban rail build electromagnetic permanent magnetic hybrid transit has been standardized. At the same time, suspension structure (such as Tongji with the rapid changes in the economic situation University-Jiading maglev experimental line), and since July, there is an urgent need for the has successfully carried out the experiment. infrastructure construction, especially like railway, Under this background, in 2014, Jiangxi to exert its pull effect on the national economy. University of Science and Technology proposed a Therefore, the small and medium-sized rail transit new type of high-efficiency intelligent permanent with the goal of promoting tourism and achieving magnet maglev rail transit system-- "Rainbow", as rural revitalization has been given a special shown in Figure 1 below. The system has the mission of the times. advantages of energy saving, environmental Suspension monorail train (also called sky protection and small space occupation. It not only train) is very popular among the cities because of expands the form of urban public transportation, the advantages of low cost, short time of but also has important reference and practical construction and flexibility. It has great market application value to alleviate urban traffic potential for the development of small and congestion and enhance travel experience. Also, medium-sized cities in the future, especially the active research on the new rail transit system is a urban areas built around the mountains, those positive attempt to promote the transformation connecting the end of the subway and residential and the upgrading of rail transit technology, to areas, etc.. Progresses in scientific and industrial innovate the rail transit mode, to optimize the

urban spatial structure, and to protect the theoretically and practically environment, which has important significance

FIGURE 1. “Rainbow” rail transit system TABLE I COMPARISON ON THE CHARACTERISTICS OF URBAN RAIL TRANSIT SYSTEM

Price（hundred Type Character Technical character Most suitable area million/kilometre）

Large capacity, low energy loud noise, high cost and Subway Large and medium-sized city 3-6 consumption and mature technology long construction period

Low energy consumption and mature Small and medium-sized cities, light rail loud vibration noise 2-4.5 technology tourist areas

Dust pollution is Small and medium-sized cities, monorail Low noise, strong climbing ability 0.5-4.5 slightly higher dedicated lines

loud noise, greatly related Between rail transit and public Small and medium-sized cities, tramcar to traffic volume and road 0.5-1.5 transport,Flexible wiring and low cost dedicated lines right

Low vibration and noise, Vehicle energy Small and medium-sized cities, maglev strong climbing ability, consumption is slightly 3-4 mountain cities,tourist area Small turning radius, little pollution higher

Low energy consumption rapid railway loud brake noise Long distance suburb 2-4 and mature technology

Connecting airports, stations Small vibration and noise, strong maglev low noise, and other scenic spots to climbing ability, small turning radius, under 0.5 skytrain Easy to build develop the new PRT traffic low cost and little pollution system

II. A NEW PERMANENT MAGNET RAIL TRANSIT SYSTEM In this paper, a new intelligent permanent magnet to the urban aerial landscape construction. The maglev rail transit system named "Rainbow" is system uses the magnetic force of rare earth proposed, which means that the system will be a permanent magnetic material to realize a smart colorful cloud over the city and contributes suspension, non-contact operation of a new air

rail transit system, and it is a suspension maglev the stable control on both left and right side, and rail transit system which incorporates permanent the upper and lower end of the electromagnetic magnet maglev, DC motor, intelligent guide structure are respectively installed with transportation. The system has the advantages of mechanical limit pulley to form the two-stage lower building cost and lower maintenance cost, guide protection structure of the guide system. In and can save more energy, protect the addition, Secondary rubber wheels are installed environment, and has less space occupation, high on the outside of permanent magnetic levitation safety coefficient and less magnetic pollution. structure to prevent vehicle from colliding with The permanent magnetic group which is made of permanent magnet array under unsteady rare earth permanent magnetic material is conditions such as turning and tilting. installed in the sky beam. The magnetic materials In the train drive system, the long stator on the motor interact with bogies to form a permanent magnet synchronous linear motor is repulsive force, so that the bogie and the attached adopted. The long stator of the motor is arranged car can be suspended, and driven by the long alternately by three phase AC windings, fixed on stator linear induction motor. It achieves an the upper wall of the inner side of the suspension operation state with safety, stability, not easy to beam, and the corresponding electric motor derail, reliability, and low operating noise. It has mover is composed of permanent magnets and the advantages of environment friendly, strong placed at the top of the suspension frame. The adaptability, all-day operation, short construction traveling wave magnetic field generated by the time, small impact on traffic, light structure, and armature winding and the static magnetic field small area occupation. It is suitable for the low produced by the permanent magnet form the and middle volume traffic of the one-way peak electromagnetic traction force and drag the section within 10,000 person / h, especially for suspension frame and the carriage to move small and medium-sized cities, tourist spots, lines forward. In the actual driving control strategy, the around rivers and lakes, and related connection conventional linear motor multi-modal control lines and so on, which is shown in Figures 2. method is adopted. According to the vehicle state, For the system function, the "Rainbow" different driving strategies is switched to adapt system can be divided into six modules, which the situation, including slip frequency control, are electromagnetic permanent magnet hybrid vector control, direct thrust control and so on. suspension control system, electromagnetic In order to improve the safety degree of guidance control system, intelligent vehicle operation and the intelligence of train communication system, permanent magnet linear service, the "Rainbow" system has applied the drive system, track and vehicle operation control technology of Internet of Things and artificial system, ground power supply system. intelligence in the on-board system. The former In the suspension guide structure, the system collects and preprocesses all kinds of field data realizes the vertical suspension of the vehicle (including levitation height, magnetic field center through Halbach permanent magnet array, and deviation, car body position, etc.) for the realizes the real-time dynamic suspension intelligent front-end system. The wireless adjustment of train safety by combining with communication equipment connects the car to the electromagnetic stability control. There are two cloud control terminal to realize the exchange of sets of preset suspension limit wheels at the top data information. The latter realizes the of the suspension frame to prevent vertical intelligent unmanned driverless and human-car suspension collision. In the horizontal direction, friendly interactive system of running, organizing, the electromagnetic steering structure completes managing and serving. The mobile terminal can

be implemented through APP, WeChat public applied, compared with the traditional number and other ways to implement the electromagnetic hybrid levitation technology, operation and personalized services, which its obvious advantages are: fully utilize the mainly include: man and machine interface adaptive characteristics of Halbach interaction, traffic data display, multimedia permanent magnet array to achieve vehicle conversion and so on, to ensure that passengers suspension; The electromagnetic force acts have good and comfortable experience. as a suspension damper to adjust the In addition, the "Rainbow" system is unstable disturbance under the static equipped with the safety facilities of the magnetic field in real time to suppress the conventional rail transit system, such as vehicle oscillation. At present, both Shanghai emergency brake button, escape ladder, smoke Maglev Train and Changsha Maglev Special alarm and so on, to ensure the overall safety and Line, which realize commercial operation in reliability of the system. China, still have great energy consumption To sum up, the "Rainbow" system is a new problems, especially Shanghai Maglev Train. type of medium and low speed rail transit system While, Changsha Maglev Train has some with the functions of stable suspension, safety improvement compared with the former in guidance, rapid driving and accurate terms of levitation power consumption. But communication. It has strong climbing ability, its suspension Energy consumption still small turning radius and flexible driving, accounts for about 40% of the total energy intelligent service and other advantages, which is consumption of trains; in addition, the high suitable for small volume and scattered mode energy consumption of trains often leads to transportation, and it has a good application the high cost of train operation and prospect for the development of small and maintenance, which makes it difficult to medium-sized cities in the future. promote further marketization. On the contrary, the "Rainbow" system uses static magnetic field to realize the suspension control of the whole structure of the vehicle. The suspension energy consumption is only generated by the electromagnetic damper, and the suspension energy consumption of the integrated train is close to zero. Moreover, electromagnetic dampers often only need to provide transient adjustment of Fig 2. Sample car schematic magnetic force, so it does not need to consider electromagnetic winding heating III. PERMANENT MAGNETIC LEVITATION and other problems. It also improve the CONTROL SYSTEM service life of circuit components, and can A. Suspension structure effectively reduce the train operation and maintenance costs. It is easy to be accepted In the "Rainbow" suspension system, by the general public and achieve the the ideal permanent magnet electromagnetic commercialization of the “Rainbow” system. hybrid suspension control technology is According to the actual demand and the Halbach permanent magnet array, which simulation analysis, the engineers designed were laid in the suspension beam track plate three groups of permanent magnets to form and suspension frame respectively, fixed by

conventional weak magnetic stainless steel of the vehicle are realized by connecting the (such as 304 stainless steel, Cr16Ni14 rotating bearings to the suspension frame. non-magnetic stainless steel), which is The suspension guide module is composed shown in Figure 3. Limited to the progress of of four groups of single point suspension engineering research, two sets of suspension structure and eight groups of rubber guide guide structures are set up on the wheels, as shown in Figure 4. Besides, The suspension frame of the actual test vehicle, specific parameters of the suspension and the suspension and guidance functions structure are shown in Table 2.

Magnetization direction

FIGURE 3. Halbach suspension permanent magnet array FIGURE 4. vehicle suspension and steering physical diagram

TABLE II PARAMETERS OF “RAINBOW” SYSTEM SUSPENSION STRUCTURE

parameter value unit

Monorail cross section area 4200 mm2

Double track mass per meter 61 kg

Double track magnet mass per meter 58.5 kg

Vehicle permanent magnet total length 1248 mm

Vehicle permanent magnet pole number 8 pole

Permanent magnet brand N45H

Permanent magnet type simplified Halbach

Permanent magnet height 30 mm

Design suspension height about 10（self-adjust） mm

The mass of suspension frame and car about 1.5 Ton

permanent magnets is greatly affected by the B. Static Magnetic Field Analysis of permanent Magnet Array vertical gap and horizontal offset of permanent magnet array, therefore, in the magnetic Combined with the basic structure of vehicle simulation analysis, we set the horizontal offset suspension frame, the static levitation force between permanent magnets as in [0-5]; In the generated by permanent magnet array is vertical direction, the gap interval is [0-40], and simulated by Finite Element Method[13,14] with six groups of sample data are used to explain it, the help of Ansoft Maxwell software. At the same as shown in Figure 5 below. Combined with time, combining with the actual test data, we actual project construction, in the simulation carry out comparative verification and analysis. analysis of this paper, the size of the permanent Because the magnetic force between Halbach

magnet block is taken as 150*30*30 magnet which are described above are of (corresponding to the length, width and height of millimeter magnitude (mm). The simulation data the permanent magnet in figure 3 respectively). in this paper mainly focus on the analysis of the The permanent magnet adopts the sintered single point suspension structure without NdFeB N45 model. The vertical gap, the considering the coupling relationship between horizontal offset and the size of the permanent adjacent levitation points.

XY Plot 1 Maxwell3DDesign2 3.50 Curve Info Force_z Setup1 : LastAdaptive level='0mm' 3.00 Force_z Setup1 : LastAdaptive level='1mm' Force_z 2.50 Setup1 : LastAdaptive level='2mm' Force_z Setup1 : LastAdaptive level='3mm' 2.00 Force_z Setup1 : LastAdaptive level='4mm'

Force_z[kNewton] Force_z 1.50 Setup1 : LastAdaptive level='5mm'

1.00

0.50 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 hight [mm] FIGURE 5. Finite Element magnetic simulation curve According to the above figure, the static the levitation height is at 10mm, the levitation levitation force of Halbach array and the gap and force is still 2.01kN and the maximum load is horizontal offset of permanent magnet decreases 0.12 Ton. Considering from the actual nonlinearly, and the attenuation rate of magnetic engineering implementation, the maximum load force decreases gradually with the increase of can be maintained at about 0.5 Ton when the height. The levitation height of medium and low horizontal deviation of the train reaches 5 mm speed maglev trains in China generally are and the suspension height is 5mm. Under the around 10 mm, while the control range of vehicle influence of nonlinear factors, when the operation is stable within the controllable range horizontal deviation is large, the attenuation of of 3mm. Referring to the basic data of the vertical levitation force is largely decreasing, medium and low speed maglev train, the static which can easily cause the unstable oscillation of levitation force of the "Rainbow" suspension the system. system can reach 3.33kN when the horizontal The effects of different horizontal deviations deviation is 0 mm and the suspension gap is 0 on the suspension force are shown in Table 3 mm. The maximum load of the permanent below. maglev structure can reach about 1.2 Ton. When

TABLE III. SUSPENSION ATTENUATION RATES AT DIFFERENT HORIZONTAL OFFSETS

Parameter category Simple data

vertical interval（mm） 0 10 20 30 40

Levitation Force of horizontal offset as 0 mm 3.33 3.3 2.01 2.0 1.25 1.245 0.795 0.791 0.513 0.513 and 2 mm（kN） attenuation rate 0.9% 0.5% 0.4% 0.5% 0.06%

Levitation Force of horizontal offset as 3mm 3.26 3.15 1.98 1.93 1.24 1.21 0.79 0.77 0.51 0.506 and 5mm（kN） attenuation rate 3.4% 2.5% 2.4% 2.5% 0.8% From the two groups of attenuation rate data, offset should be taken into account in the actual under two horizontal offsets condition, we can load design and redundant suspension design see that the vertical suspension attenuation rate should be added. Combined with the simulation shows a decreasing trend. Combined with Figure curve of static magnetic field levitation force, the 5, the attenuation of vertical suspension force is influence of horizontal offset and suspension gap affected by the horizontal offset obviously, such on 3D direction is studied and analyzed in this as the 10mm suspension height moment, the paper. In the figure, the levitation height range is attenuation rate of the first group was two [0-20] and the step length is 5mm. The horizontal percentage points higher than that of the second offset ranges from 0 to 40, with a step length of 1 group. This means that the effect of horizontal mm, as shown in Figure 6. XY Plot 4 Maxwell3DDesign3 XY Plot 6 Maxwell3DDesign3 4.00 3.50 Curve Info Curve Info Force_y Force_z Setup1 : LastAdapti... Setup1 : LastAdaptive 3.00 hight='5mm' hight='5mm' 3.00 Force_y Force_z Setup1 : LastAdapti... Setup1 : LastAdaptive 2.50 hight='10mm' hight='10mm' 2.00 Force_y Force_z Setup1 : LastAdapti... Setup1 : LastAdaptive 2.00 hight='15mm' hight='15mm' Force_z 1.00 Setup1 : LastAdaptive 1.50 hight='20mm'

1.00 Force_z[kNewton] 0.00 Force_y[kNewton]

0.50

-1.00 0.00

-2.00 -0.50 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 level [mm] level [mm] （a）（b）

XY Plot 8 Maxwell3DDesign3 1.50 Curve Info Force_x Setup1 : LastAdaptive 1.00 hight='15mm' Force_x

0.50

0.00

Force_x[newton] -0.50

-1.00

-1.50 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 level [mm]

（c）（d） FIGURE 6. Static Magnetic Field Force Curve Under Finite Element Simulation Interface The figure shows:(a) The trend of static different positions, the vertical magnetic force vertical force changes under different levitation decreases nonlinearly with the increase of gap conditions, (b) the horizontal magnetic force horizontal deviation. When the horizontal offset with several horizontal displacements under the is 25mm, the levitation magnetic force is almost levitation gap, (c) the longitudinal magnetic force equal, which is about 0.5 kN, and the magnetic along the orbital direction under different force between magnets is repulsive. When the levitation gaps (d) 3D magnetic force trend with offset is about 30mm, the perpendicular magnetic different suspension gap and horizontal offset. force of the permanent magnet array is close to In (a), when the suspension gap is in zero, and then increases gradually, and the

magnetic direction reverses (from the original lateral force, especially when the suspension gap repulsive force to the attractive force), and the is small, which requires the guidance control rate of change is different before and after the system to have strong anti-disturbance and magnetic direction flipping. That is, the magnetic correction ability, as well as the necessity of suction attenuation rate is slightly smaller than introducing the secondary steering structure. In the magnetic force attenuation rate. In (b), the (c), the amplitude of magnetic force generated by horizontal magnetic force increases nonlinearly the permanent magnet array in the direction of with the increase of horizontal offset, and then travel along the orbit is basically zero, and will decreases gradually. The smaller the gap, the not change with the horizontal offset, but the faster the magnetic growth and the larger the direction is basically irregular. The influence of amplitude. The maximum horizontal magnetic magnetic force along the track direction wasn’t force is obtained when the offset reaches about taken into account in the actual engineering 25mm (when the suspension gap is 0 mm, the design. In (d), the horizontal offset and levitation maximum magnetic force is 3.03 kN; when the clearance of the upper and lower permanent suspension gap is 25mm, the horizontal magnetic magnetic arrays are taken as the variable axis, force is up to 1.04 kN). It can be seen that under and the three-dimensional integrated magnetic the ideal condition, which means the horizontal force (scalar) between the permanent magnetic deviation is 0 mm, the horizontal steering force arrays is drawn by finite element simulation. The can realize "zero" power operation. When the magnetic force relationship between the gap and horizontal offset is larger than 5mm, the the offset is more intuitively reflected permanent magnet array has strong horizontal For the distribution of magnetic field intensity, as shown in Figure 7 below:

（a） rail cross section （b） suspension group magnetic field cross sections

（c） permanent magnet suspension group magnetic field side

（d）Internal Distribution Map of permanent magnet suspension combined Magnetic Field

FIGURE 7. Magnetic field intensity distribution in several states It can be seen from the diagram that the It can also be seen that the magnetic field magnetic field intensity on the track line is intensity of the double layer Halbach array does basically concentrated on the contact surface not conform to the principle of magnetic field between the Halbach permanent magnets with the superposition. maximum intensity of 1.048 kT, which is In combination with the location of the A ,B, nonlinear attenuated with the increase of the C, D sample in Figure 3, we have carried out the distance. The magnetic field intensity between field data acquisition, and the magnetic induction the suspension points is obviously increased. The intensity data sample of the permanent magnet magnetic field energy is mostly concentrated on array along the track is shown in the following the surface of the central magnet, and the Table 4. maximum internal intensity can reach 1.8346kT.

TABLE IV SAMPLE DATA SHEET OF MAGNETIC INDUCTION INTENSITY DISTRIBUTION

Distance To The Permanent Sample Point（T） Magnet Surface（mm）

vertical interval A B C D Level Interval

0 856 993 984 853 432

5 355 538 627 330 246

10 190 401 395 180 156

15 115 247 355 110 93

20 71 210 347 66 61

It can be seen from the sample data that the variation span of the magnetic field intensity is distribution of the actual magnetic field intensity large. On the other hand, Figure 7 and Table 4 is in good agreement with the finite element further illustrate that the magnetic energy of simulation curve. The energy of the magnetic Halbach permanent magnetic arrays is basically field is distributed in the position of B and C, within the centimeter level of space, The distance whose trend is high in the middle and low on the between the car position and the suspension sides, and the width of the isopotential line on module of the "Rainbow" system is more than both sides is relatively narrow, that is, the one meter and the design height of the column is

about 7.9 meters. Structurally, the magnetic track of the "Rainbow" system, residents, they energy of the suspension module is basically will not be affected by the magnetic field shielded from the beam. Therefore, for intensity of the permanent magnet. passengers in the car and pedestrians along the

C. Simulation Discuss and Structural Optimization In order to verify the simulation results, the of the corresponding suspension gap by actual test sample data are compared with the increasing the load on the vehicle suspension finite element simulation data, as shown in frame. Table5. The actual data obtained the mean value

TABLE V SIMULATION OF SUSPENDED VERTICAL MAGNETIC FORCE AND PRACTICAL MEASUREMENT DATA SHEET

force capacity with no capacity with no suspension gap real single-point theoretical deviation theoretical real capacity(kg) carrying capacity （mm） capacity(KN) （KN） deviation(kg) deviation rate

18 1.375374 1.3475 1100 1100 2.03%

19 1.310526 1.21275 1000 990 7.46%

23 1.039977 0.94875 832 750 8.77%

26 0.9499551 0.77175 760 630 18.76%

34 0.6648323 0.57075 532 450 14.15%

39 0.5615267 0.47775 449 390 14.92% In the above table, the actual single point simulation data in Figure 5 are drawn into line bearing capacity has a certain attenuation diagram verification analysis, as shown in Figure compared with the theoretical one, but the overall 8. attenuation rate is relatively low, which basically meets the magnetic requirements of the actual vehicle operation. The deviation rate of magnetic force at the 26mm moment of suspension gap is about 19%. Combined with chapter C, the bearing capacity of suspension frame is not only related to suspension clearance, but also affected by horizontal deviation. Some of the sample points in Table 5 are affected by the detection position, resulting in a large magnetic deviation FIGURE 8. Finite element Simulation and actual rate, which likely the error caused by the Measurement Curve (Vertical Force) horizontal offset. Several sets of sample data and

It can be seen from the above diagram that such as permanent magnet magnetization state, the actual vertical levitation magnetic force is magnetic conductors and magnetic flux leakage. basically consistent with the attenuation trend of In addition, in the design of the "Rainbow" the simulation curve, and the actual bearing suspension guidance system, there is a certain capacity is above 80% of the theoretical bearing offset redundancy and the nonlinear variation of capacity. The actual vehicle bearing capacity is the horizontal and vertical force in the steering affected not only by suspension clearance and mechanical structure, which often leads to the horizontal offset, but also by external factors instability of the actual suspension position. As a

result, part of the position was mismeasured is requirements of vehicles. Therefore, the also possible. Combined with the whole sample combination of Halbach permanent magnet array data, the finite element simulation capacity is is simulated in this paper. basically consistent with the actual suspension From the simulation results of levitation force bearing capacity, which provides a certain and horizontal force, it can be seen that the static scientific research value for the subsequent magnetic field force between permanent magnets suspension stability control. is large, which is very difficult for engineering In the mixed suspension structure, the assembly and can easily cause bumps between static suspension mainly depends on the permanent magnets. For this purpose, permanent magnet, which needs a large number non-magnetic materials (such as epoxy resin) of permanent magnets laid along both sides of the were filled in the Halbach permanent magnet track in the engineering construction. However, array combination gap. In this way, not only the the precious rare earth resources lead to the high difficulty of permanent magnet assembly can be price of the high-performance permanent magnet effectively reduced, but also the demand for in the market. This will also affect the application permanent magnets in practical construction can of the "Rainbow" system. As far as construction be reduced to a certain extent. It can be seen from cost is concerned, compared with the traditional the simulation that the thickness of the laminated rail transit system, the system has the advantage plate has a certain influence on the levitation of lower cost, but in engineering and design, it magnetic force, and the influence degree of the should save materials and reduce engineering thickness is shown in Figure 9. cost as much as possible while ensuring the basic XY Plot 2 Maxwell3DDesign1 3.43 Curve Info Force_z 3.00 Setup1 : LastAdaptive x1='-4mm' Force_z 2.50 Setup1 : LastAdaptive x1='-3mm' Force_z Setup1 : LastAdaptive 2.00 x1='-2mm' Force_z Setup1 : LastAdaptive x1='-1mm' 1.50 Force_z[kNewton]

1.00

0.50

0.00 -200.00 -100.00 0.00 100.00 200.00 300.00 387.46 x [mm] （a）（b）

FIGURE 9 .Halbach permanent magnet array gridding and the effect of laminated plate thickness on vertical magnetic force Figure (a), we pay attention to the skin influence on the maximum vertical levitation effect between permanent magnets, the magnetic force. The five groups of data all have a simulation surface depth is set to 2 mm; In figure certain degree of magnetic attenuation, and the (b), x1 denotes the thickness of the adding layer, attenuation rate of the adjacent thickness curve is x denotes the displacement of the short rail along about 0.5%. Because the magnetic field the direction of the track, and the starting point of distribution is relatively uniform and the the short rail is set to (150+ X) mm, the magnetic force is large, the effect of laminated thickness of adding layer is set to (5+X) mm; the plate on the stability of the whole suspension starting point of the long rail is set to 0 mm, the force is relatively small, so the curve is basically thickness of the adding layer is [0,5] and the kept smooth. To sum up, the thickness of the sampling step is 1 mm. laminated plate should be considered It can be seen from the above figure that the synthetically in the actual engineering design, thickness of the laminated plate has obvious such as the actual load requirement and the cost

estimate and so on. levitation magnetic force. According to Newton's second law and D. Stability Analysis of suspension system equation of suspension (1), the equation of state In the electromaglev system composed of of levitation system in vertical magnetic field can Halbach permanent magnet array, due to the lack be obtained, without considering the influence of of damping term in the equation of state of the horizontal deviation. system, the system presents a critical stable state ℎ̇ = 푣 { (3) [15]; At the same time, the static suspension 푣̇ = 퐹(ℎ)/푚 − 푔 system also presents a certain volatility in the In the formula, v denotes the displacement actual suspension magnetic force detection, so velocity of the vehicle in the vertical direction this paper will combine the magnetic force and m represents the mass of the whole analysis of the suspension system to judge the suspension structure. stability of the static suspension system. For this kind of time-varying suspension Since the 1970s, researchers have put systems, researchers often study the stability of forward many strategies for the study of the controlled system by analyzing the stability magnetic field of Halbach permanent magnetic of the system at the equilibrium point. In arrays, which can be divided into: finite element reference [ 22 ], it is shown that there is a simulation [16], sinusoidal approximation [17], nonlinear exponential function relationship electronic circulation analysis [ 18 ], magnetic between the magnetic field of single layer charge method [19]. However, in many research Halbach and the suspension gap. In the actual methods, magnetic field analysis is often carried suspension control, the adjustable control range out for the modes of rotating motor [20] and of the general electromagnetic maglev train is electric suspension structure [21], but there are kept within the 3mm, while the "Rainbow" few references for static magnetic force analysis suspension system is designed to develop the between double-layer Halbach permanent "personal rapid rail transit system", that is, the magnetic arrays. Therefore, in this paper, the carrying capacity of the car can contain 4-6 finite element magnetic simulation curve is people. Combined with the simulation curve of obtained by MATLAB fitting tool between suspension force, the height of suspension vertical levitation force and suspension clearance. control is basically kept within the adjustable According to the fitting function, the steady state range of 5 mm, in addition, on the suspension analysis of the static suspension system is carried frame mechanical protective wheels with out. horizontal and vertical direction are set to avoid The fitting function is as follows: the large suspension fluctuation of suspension confidence interval is 95%. structure. Therefore, by obtaining the equilibrium 퐹(ℎ) = 푎 ∗ 푒(푏∗ℎ) + 푐 (1) point, the stability of the equation of state of the The magnetic force function of the levitation system is analyzed by using the Taylor formula in height h is the F(h), and the fitting parameter is: the local linearization expansion at the 푎 = 3426，푏 = −58.26, 푐 = 202.2 equilibrium point. Functional fitness: At the equilibrium point, the equation of suspended state is : 푆푆퐸 = 0.0116 { 푅 − 푠푞푢푎푟푒 = 0.9996 > 0.9 (2) ℎ̇ = 푣 = 0 푅푀푆퐸 = 0.01747 { 푎∗푒(푏∗ℎ)+푐 (4) 푣̇ = − 푔 = 0 According to formula (2), the fitting 푚 function is in excellent agreement with the actual By formula (4), we can get:

푣0 = 0 response of the system will be close to the { 1 푚푔−푐 (5) ℎ = ∗ 푙푛( ) 0 푏 푎 equal-amplitude oscillation when there is a slight In the formula (5), the parameters can be external disturbance. Moreover, it is not calculated or measured in practice, that is, when controllable by itself. the mass of the vehicle is known, the suspension height under the static magnetic field will be

stabilized at ℎ0 and the vertical displacement velocity will be zero. When formula (3) is expanded by Taylor formula, the linearized equation of state is obtained as follows: ℎ̇ = 푣 { (6) 푣̇ = k(ℎ − ℎ0)

푏(푚푔−푐) Among them,k = , assume that x = 푚 FIGURE 10. Response Waveform of Vertical displacement

ℎ − ℎ0,y = 푣. The equation of state space of the and Velocity system can be obtained : E. Design and Analysis of Electromagnetic ẋ 0 1 x [ ] = [ ] [ ] (7) Constrained Damping System ẏ k 0 y From the formula (7), the characteristic In the analysis of the above section, the train equation of the suspension system is obtained as suspension system cannot meet the requirements follows: λ2 + 푘 = 0 of train safety and stability only by static From (1) we know that 푏 < 0, 푚푔 ≫ 푐 . magnetic force. Combined with the development Therefore, the state matrix equation of the system of modern electromagnetic permanent magnet is the second order system, and its eigenvalue has hybrid magnetic levitation technology, a pair of imaginary real roots with the real part as electromagnetic constrained damping system is zero, that is, the system is in the state of zero introduced into the "Rainbow" suspension system, damping[23](pp. 51–63),λ1,2=±j√푘 . In other and the static magnetic field force is words, the equilibrium point of the suspension supplemented and slowed down by using the system under the static magnetic field is critical controllability of electromagnetic force. The stable after linearization. hybrid suspension structure can be divided into Combined with the above deduction, the permanent magnet array and electromagnetic coil, formula (7) is solved numerically at a certain and its structure is three views, as shown in equilibrium point by using MATLAB simulation Figure 11. （1） platform. Taking 푚 = 750푘푔，푔 = 10푚/푠2 ,

initial value (ℎ0, 푣0) = (28, −1), 23mm is the

height of suspension in response to the （2）

equilibrium point, and the dynamic trend of （1）Coil winding （2）Secondary guard wheel suspension frame under the action of static （3）Halback permanent （3） magnet array magnetic field can be obtained, as shown in Figure 10. From the velocity curve and FIGURE 11.. Three views of hybrid suspension structure displacement curve, it can be seen that a single F. physical models static permanent magnet structure can realize the relative stability of the suspension system, but the First, it is assumed that there is no magnetic field coupling between the electromagnetic winding

and the Halbach permanent magnet array, and the expansion (neglecting the higher-order term) for electromagnet is in the state of non-magnetic the magnetic force of (8): saturation and so on. In ideal conditions, the 퐹 = 퐹(𝑖, ℎ) = 퐹 (𝑖 , ℎ ) + 퐹 (ℎ ) 0 1 0 0 2 0 suspension is subjected only to magnetic field ’ ’ +퐹1(𝑖0, ℎ0) + 퐹2(ℎ0) ’ ′ force and vehicle gravity, in the vertical direction 퐹1(𝑖0, ℎ0) = 푓𝑖 (𝑖0, ℎ0)(𝑖 − 𝑖0) (12) ′( )( ) of the dynamic equation: +푓ℎ 𝑖0, ℎ0 ℎ − ℎ0 ’ ′ {퐹2(ℎ0) = 푓ℎ(ℎ0)(ℎ − ℎ0) 푑2ℎ(푡) m 2 = 퐹0 + 푚푔 { 푑푡 (8) F𝑖(𝑖0, ℎ0), Fℎ(𝑖0, ℎ0) is derived from the 퐹 = 퐹 (𝑖, ℎ) + 퐹 (ℎ) 0 1 2 differential partial derivative formula:

In the formula: 푭 -- magnetic field 휕푓 (𝑖,ℎ) ퟎ 푓 (𝑖 , ℎ ) = ( 1 |𝑖 = 𝑖 , ℎ = ℎ ) 𝑖 0 0 휕𝑖 0 0 force,푭ퟏ(풊, 풉)-- Electromagnetic force,푭ퟐ(풉)-- 𝑖0 = 2퐾 2 magnetic field force of permanent magnet, ℎ0 휕푓 (𝑖,ℎ) 품 --gravity acceleration, The equation of 푓 (𝑖 , ℎ ) = ( 1 |𝑖 = 𝑖 , ℎ = ℎ ) ℎ 0 0 휕ℎ 0 0 (13) 2 electromagnetic force for single point 𝑖0 = −2퐾 3 electromagnetic system [24]: ℎ0 ’ 휕푓2(ℎ) 2 퐹 (ℎ ) = ( |𝑖 = 𝑖 , ℎ = ℎ ) 𝑖 2 0 휕ℎ 0 0 퐹1(𝑖, ℎ) = 퐾 ( ) 푏ℎ { ℎ (9) { = 푎푏푒 0 푢 푆푁2 퐾 = − 0 4 To simplify the expression, it is assumed

The relationship between voltage and that 푘1ℎ, 푘1𝑖, 푘2 represents the first partial current in the electromagnet winding can be derivative of the electromagnetic force to the gap expressed as follows: and current at the equilibrium point, and the first

푑𝑖(푡) partial derivative of the static magnetic field 푈(푡) = 푅𝑖(푡) + 푙 (10) 1 푑푡 force to the gap, respectively. Available from the In the formula: R-- electromagnet formula (12) and (13):

winding resistance, 풍ퟏ -- equivalent 퐹(𝑖, ℎ) = (퐹1(𝑖0, ℎ0) + 퐹2(ℎ0)) + (14) inductance of electromagnet winding. (푘1𝑖(𝑖 − 𝑖0) + 푘1ℎ(ℎ − ℎ0) + 푘2(ℎ − ℎ0)) When the suspension system is in the The system model equation after equilibrium position, the suspension system linearization can be obtained by substituting the under the static magnetic field realizes the critical formula (11) with the formula (14)：

stable state, and the electromagnetic constrained 푑2ℎ(푡) m = 푘 (𝑖 − 𝑖 ) + (푘 + 푘 )(ℎ − ℎ )(15) damping system achieves the effect of fine tuning 푑푡2 1𝑖 0 1ℎ 2 0 the suspension state, then the real-time control of Laplace transformation for linearized model the hybrid system belongs to a kind of bounded equation：

regulation. From the expressions (1) and (9), we ℎ(푠) 푘1𝑖 = 2 (16) can see that the magnetic force of the suspension 퐼(푠) 푚푠 −(푘1ℎ+푘2) system has a complex nonlinear relationship. The controlled output relationship between Therefore, in this paper, the nonlinear system is gap and current is described in formula (16), and linearized by Taylor series at the suspension the controlled relation between voltage and gap equilibrium. can be transformed by formula (10).

Suppose that (𝑖0, ℎ0) is an equilibrium In addition, the characteristic equations of point of a hybrid suspension system, which is electromagnetic permanent magnet hybrid open obtained by (8): loop suspension system can be obtained by (16). 2 0 = 퐹1(𝑖0, ℎ0) + 퐹2(ℎ0) + 푚푔 (11) 푚푠 − (푘1ℎ + 푘2) + 푘1𝑖 = 0 (17) It is easy to obtain the Taylor formula Due to k < 0, the open-loop poles of

levitation system are easily obtained: H. Experimental verification and discussions

1 𝑖2 𝑖 푏ℎ0 0 0 At present, the project is still in the basic 푠1,2 = ±√ [(푎푏푒 − 2퐾 3) − 2퐾 2] (18) 푚 ℎ0 ℎ0 research stage, and the electromagnetic There is an open loop pole in the right half constrained damping system is still in the plane on the complex plane of the system. theoretical stage, but its structure and principle According to the Routh Criterion, the hybrid are basically the same as the electromagnetic suspension structure composed of permanent suspension ball system. In this paper, the control magnet array and electromagnetic constrained strategy of electromagnetic constrained damping damping system belongs to an unstable structure in a single point suspension ball system is of its own, but the system is still observable and studied. controllable. The suspension control model can The state space model of the suspension be adjusted by external control strategy to make system based on the parameters of the real single the whole suspension system stable. point suspension ball system is as follows: 푥̇ 0 1 푥1 0 G. Electromaglev control strategy [ 1] = [ ] [ ] + [ ] 푈 푥̇ 980 0 푥2 2499 { 2 (22) Because the oscillation amplitude of the 푥1 푦 = [1 0] [푥 ] hybrid suspension control system is relatively 2 In the formula, x1 and x2 represent the small under the stable state, the suspension force displacement and velocity of the suspension ball under the static magnetic field can be respectively, and the matrix rank discriminant approximately considered as a constant value, 푤푐>0,푀푐>0 ,respectively. while the electromagnetic constrained damping For linearized systems, the state feedback system can suppress and adjust the momentum of control of linear time-invariant systems can be the suspension oscillation. used for pole assignment of formula (22). Combined with the formulas (8) and (11), it According to the expected performance of actual is obtained that: control, this paper selects the dynamic control 푑2ℎ(푡) 𝑖 2 m = 퐹 (ℎ ) + 푚푔 + 퐾 ( ) (19) performance index: the overshoot quantityδ1 ≤ 푑푡2 2 0 ℎ 5% ,and the adjustment time is less than 3 s. The state space equation of the Combined with the reference [25](p.111), the electromaglev control system is obtained by performance index of the controlled object is expanding at the equilibrium point： deduced, and the damping ratio ξ ≥ 0.69 and 0 1 푥 0 푥1̇ 1 the natural frequency ω푛 ≥ 1.65 are obtained [ ] = [푘1ℎ ] [ ] + [푘1𝑖] 퐼 푥̇ 0 푥 2 푚 2 푚 (20) under the preset state. 푥1 푦 = [1 0] [ ] The corresponding expected closed-loop { 푥2 dominant poles (critical points) are: In the formula, x 1 and x 2 represent 2 suspension displacement and suspension 푠1,2 = −ξω푛 ± ω푛√ξ − 1 displacement velocity, respectively. Clearly, in = −1.138 ± 픧1.194 (23) the matrix rank discriminant of the equation of The characteristic polynomials of the state state: feedback system are as follows: 푘 0 1𝑖 푚 | λI − (A − bK)| = (푠 + 1.138 − 픧1.194)(푠 푤푐 = [퐵 퐴퐵] = [푘 ] ≠ 0 1𝑖 0 푚 (21) + 1.138 + 픧1.194) 2 푇 1 0 = 푠 + 2.276푠 + 2.721 (24) { 푀푐 = [퐶 퐶퐴] = [ ] ≠ 0 0 1 If the corresponding coefficient is equal, the The system has complete controllability feedback matrix is obtained: and observability.

K̅ = [ 1516.279 −2.276] coil), and the adjusting time is about 2 s, as 0 1 2499 0 shown in Figure 12 below. 푃1 = [퐵 퐴퐵] [ ] = [ ] { 1 0 0 2499 (25) 1516.279 −2.276 퐾 = K̅푃−1 = [ ] 1 2499 2499 The linearized state space equation after the state feedback pole assignment method is as follows: 푥̇ 푥 [ 1] = [퐴 + 퐵퐾] [ 1] + B푈 = 푥2̇ 푥2

0 1 푥1 0 [ ] [ ] + [ ] 푈 (26) 2496.279 −2.726 푥2 2499 The state feedback control strategy is tested on a single point suspension ball system, as shown in figure 12-14. According to the above theoretical derivation, the system model with linearized pole Figure 12. Output Curve of suspension system under Linear assignment is simulated in MATLAB/Simulink. State Control Among them, the output voltage is set to 5.8 V, the suspension ball position is basically stable at 5.1mm (distance to the bottom of the winding

device, digital-to-analog converter, etc.) will also I. Experimental result affect the quality of the system response output. A single point suspension ball system Therefore, there are a few burr pulses in the belongs to a voltage input electromagnetic voltage response of the system, which can be adsorption suspension structure. In the actual regarded as the signal output within a reasonable control system, the voltage input signal of the range. suspension system is analyzed. In Figure 13 and 14, the initial voltage signal is set to 5.8 V and the system responds to the voltage curve within 5 S. From the system response, it can be seen that the signal input is basically stable at 5.8V, and remains within the fluctuation range of [5.5,6.5]. Among them, there is obvious "instantaneous burr pulse" phenomenon in the unit time voltage output. From the point of view of control algorithm, linear state feedback control belongs to a real-time dynamic adjustment strategy. The voltage output of the floating system is adjusted in real time by the change of the position of the suspension ball. In terms of the hardware structure of the suspension system, the type of circuit components used in Figure 13. Output response of suspension ball system the system (including capacitance, resistive In the suspension structure of the "Rainbow"

system, the stable oscillation of permanent and reasonable. magnet static magnetic field maintains in 5 mm, the ultimate purpose of electromagnetic structure design is to use electromagnetic restraint damper to suppress vibration impulse in real time, to slow down vehicle oscillation, and to ensure the safety and comfort of train operation. For a single point suspension ball system, the linearized state feedback control has a good control effect. The suspension ball is basically Figure 14. Actual suspension ball position control curve stable within the 2 mm range, that is, the vibration range is 4 to 6 mm, and it has a strong ability to adjust the disturbance. Therefore, the linear state feedback control strategy is feasible

system. Each part realizes stable operation IV. Conclusions and Future Work through intelligent coordination of central For small and medium-sized cities, the control unit. The system has the advantages of increasing demand for urban transportation, the intelligence, ecology, economy and so on. It is serious lag in the construction of subway and suitable for the development of public other rail transit, and the acceleration of the pace transportation and urban landscape construction of urban life, the demand for the construction of in modern and future small and medium-sized a new type of urban rail transit system is cities. Finally, the feasibility of the suspension increasingly urgent. On the other hand, with the control system is simulated and analyzed by development of maglev technology and the Finite Element Method using Maxwell software. gradual completion of commercialization The stability of the suspension structure of the process of maglev train, The advantages of train is demonstrated by the electromagnetic energy-saving and environmental protection and suspension control system. The results show that strong adaptability of medium and low speed the electromagnetic permanent magnet hybrid maglev trains have become increasingly suspension structure is reasonable and security. prominent and the potential commercialization The proposing of the "Rainbow" system is advantages have gradually emerged, which is aimed at the development of a new traffic system one of the research hotspots for the next with small-sized maglev trains at medium and generation development of urban rail transit low speed in the future, it is one of the effective technology. Therefore, For the diversification of ways to realize the zero emission of urban public urban rail transit system, the quality of public facilities and alleviate the criticism of urban facilities in the future and the trend of public transport system. It is also an important individualized development, in this paper, a new reference for the development of new PRT intelligent permanent magnet maglev rail transit traffic system in the future, and opens a new way system is proposed. The system consists of for the development and application of maglev Halbach permanent magnet array suspension technology. Combined with the latest control system, permanent magnet linear developments of maglev trains in China, a rail synchronous motor drive system, intelligent transit network system with 'high speed maglev communication system and operation control

train connecting node cities, medium and low suspension guides, including simple turnout、 speed maglev as urban artery and small magnetic double slip switches etc., to achieve a more levitation as terminal access' may be formed in concise and efficient switch system is one of the the future, And with roads, railways, airplanes, key technologies to be solved in the shipping and pipeline transportation, they will development of maglev technology in the future. form an integrated modern transportation (5) Application and promotion: in view of the system. strong climbing ability, small turning radius and At present, the "Rainbow" system is still in light weight of the system, instead of occupying the stage of theoretical research and land, the "Rainbow" system will actively seek to infrastructure experiment, and there is still the promote and apply the complex environment, need for the optimization and improvement of such as bay, valley, channel, cross-river and so the structure and operation control system. The on, as well as the special town, campus and so next work will be carried out in the following on, to provide a reference and reference for aspects: (1) extension of the test line: the first modern intelligent traffic. phase of the engineering test line is only 60 meters, supported by the station room and four Acknowledgments: Since the establishment of columns, used for basic theoretical research and the project in 2015, the research, development, feasibility verification. Next, the test line will be and construction of the system have been extended to 336 meters, by which time the strongly supported by the Ministry of Industry extended line will cover all experimental and Information Technology. It has also obtained operating environments such as straight lines, the help from Southwest Jiaotong University, bends, steep slopes, track switches, as well as Beijing Jiaotong University, National University vehicle marshalling operations. (2) structural of Defense Technology, Tongji University, and optimization, cost reduction: in static suspension Institute of Electrical Engineering of Chinese structures, horizontal steering force is subjected Academy of Sciences, China CRRC, Ganzhou to horizontal deviation. How to optimize the Fortune, Shandong Laigang Construction, permanent magnet structure to reduce the Dongguan Hongcan, Changzhou Pacific and difficulty of steering system control will be one other units for their support and assistance. Here, of the next research directions. (3) the author expressed sincere gratitude to the Electromagnetically constrained damper and above units. At the same time, I am very grateful electromagnetic guiding structure: in the to all the teachers and students of our school's suspension and guiding system, the "Rainbow" rail transit system research group for electromagnetic winding module is introduced, their long-term support and guidance. the electromagnetic winding is used to increase the damping, and the vertical vibration of the Funding: National Natural Science Foundation system is suppressed; The mechanical guide of China （ No.61763016 and 61603306 ） ; wheel is replaced by electromagnetic guide to National key research and development plan achieve the non-contact guidance of system and advanced rail transit special the non-contact operation. (4) track switch: the （No.2017YFB1201105-12）; Jiangxi Provincial existing maglev technology is still weak in the Natural Science Foundation switch control system. Its efficiency and （No.20171BAB202030）; Jiangxi Provincial reliability need to be improved. The research Department of Education Science and team further explored new types of track Technology Research Key Project （ No. switches of electromagnetic structures and GJJ170514 and GJJ150620）.

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