A superconducting magnetic levitation system for high speed and mass transportation is being developed in Japan. Various types of running tests have already been carried out on the Yamanashi Maglev Test Line. We developed a large capacity Pulse Width Modulation (PWM) inverter as a power conversion system to drive Linear Synchronous Motors (LSM). To reduce the capacity required for the power conversion system, we installed a neutral point bias control system in the inverter for driving the LSM at the Yamanashi Maglev Test Line. This paper describes the results.

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The ground coils to be used along the entire length of a Magnetically Levitated transportation (MAGLEV) system need to withstand long-term outdoor service and be provided in extremely large quantities. It is for these reasons that we require them to be durable and inexpensive. Dicyclopentadiene, a major component of low viscous liquid in Reaction Injection Molding (RIM), is injected into the mold. It reacts with catalyst and cures in a short time to produce a substance featuring superior quality not obtainable by the conventional injection molding. Besides, the molding process may be undertaken at normal temperature and pressure, the molding equipment is inexpensive, and the insulation scheme of the wound coils can be simplified. Thus, there are several reasons that the ground coils are suitable for mass production. In this paper we discuss the application of RIM technology through our trial manufacture of practical ground coils incorporated with several improvements. We investigated the economic effect as well.

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At the Yamanashi maglev test line, two types of ground coils are used. One is for propulsion and the other for levitation and guidance. To confirm the characteristics of electromagnetic force of the ground coil for levitation and guidance, we measured the electromagnetic force directly with a measurement coil. The measurements of electromagnetic force, magnetic spring and current corresponded with the computed values to prove that the characteristics of electromagnetic force satisfy the design requirements.

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In the second year of vehicle-running tests on the Yamanashi Maglev Test Line, tests involving two trains were performed with the addition of the second train set, by using both the northern and southern lines. Furthermore, the cars of the two train sets were rearranged to compose a five-car train set. Vehicle-running tests were performed by using this long train set, and the characteristics of vehicle dynamics were confirmed on the intermediate car that was connected on both ends to other intermediate cars (not connected to any leading cars). In these tests, a maximum speed of 552 km/h was attained in a manned vehicle run.
Reported here are mainly the characteristics of vehicle dynamics obtained from vehicle-running tests at constant speed of 500 km/h, vehicle dynamics of two trains passing each other, vehicle dynamics of the five-car train set, and new control technique applied recently for improvement of ride comfort.

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The Yamanashi Maglev system has two types of main braking systems: regenerative braking system (primary brake using electrodynamic power) and on-board mechanical braking system (backup brake). The mechanical backup braking system is installed on vehicles. It is used to safely and accurately stop the vehicle in case the electrical braking system has failed. On the Yamanashi Maglev Test Line, an aerodynamic braking system is used as an element of the mechanical backup braking system. In the aerodynamic braking system, braking force is obtained by aerodynamic drag which is generated by unfolded brake panels. The aerodynamic brake is very effective in high speed operation, because the aerodynamic drag is proportional to the square of vehicle speed. This paper reports the aerodynamic brake system and results of running tests on the Yamanashi Maglev test line.

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On the Yamanashi Maglev Test Line, on-board superconducting magnets vibrate due to harmonic magnetic fields caused by ground coils while vehicles are running. Excessive vibration gives rise to a large heat load and makes it difficult to keep the superconducting state of the magnets. Therefore, the authors tested the superconducting magnets for vibration characteristics under these harmonic magnetic fields by an electro-magnetic vibration simulator. In this paper, the results of running tests are compared with those of simulations of the electro-magnetic vibration, and the analysis of vibration modes and components are introduced.

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The superconducting Maglev system suspended by EDS intrinsically has negative magnetic damping. In order to improve the magnetic damping, we used a linear generator by controlling the power factor of the current in the linear genetator coils. We developed a PWM converter and a simulator ( using Micro Cap VI ) for this control. This paper describes how to control the PWM converter and subsequently the power factor and the result of confirmation of this control method through simulation and synthetic bench tests. We can now control the PWM converter and the power factor without affecting the output power.

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We set three microphones, each with a parabolic reflector, to measure vehicle noise on the Yamanashi Maglev Test Line. Using a personal computer, we analyze the noise from the surface of the car. In this paper, we explain the noise measuring system used for this study and data processing, focusing on the calculation of sound-levels, analysis of time-dependent signals and visualization of the noise. We started to measure the noise in April 1999 to collect the data required to reduce the noise level. There is no noise from the car windows as has been expected, since we have designed the window to be smooth and even on the outer surfaces, while high-frequency noise from around the trucks and doors is recognized at 500 km/h. The noise of gas turbine is at low levels.

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We have been studying the application of a permanent magnet synchronous motor (PMSM) for railway vehicle traction in order to reduce the weight and size of direct drive traction motors. As a part of this study, it is required to establish a current control system of PMSM suitable for railway vehicle traction. In this paper, we discuss the current control system mentioned above and suggest a method which is available under the condition of railway vehicle traction. Next we investigate how to decide the current response time constant T_d and reach a conclusion that about 10ms is appropriate under some assumed conditions. Then we check this current control system, when used for railway vehicle traction, through experiments and studies on influence of parameter changing and sudden changes in the line voltage. Finally we can conclude that the current control system has satisfactory performance for railway vehicle traction.

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The running tests at the Yamanashi Maglev Test Line verified the engineering characteristics of JR's Maglev and the necessary functions as a means of transportation. The technical evaluation committee of the Ministry of Transport reported an evaluation result to the effect that the reliability of the system for commercialization has been proved from the engineering viewpoint though there are problems to be further studied on the durability and economy toward the verification of the system.

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