Erimitsu Suzuki

A Study of Vibration Control Systems for Superconducting Maglev Vehicles

The superconducting magnetically levitated transport (Maglev) system is conceptualized as a next-generation high-speed transportation system. For practical use, it is important to achieve adequate ride comfort particularly in high-speed running. Maglev vehicles are composed of lightweight car bodies and relatively heavy bogies which are mounted with devices such as superconducting magnets (SCMs) and an on-board refrigerating system. In this magnetically levitated system, the passive electromagnetic damping in the primary suspension between the SCMs and ground coils is very small. Therefore, it is effective to add active electromagnetic damping to this primary suspension, and to adjust the secondary suspension between the car body and bogie. This paper examines vibration control systems of the Maglev vehicle using actuators for the secondary suspension. Moreover, the estimated electromagnetic damping, which interacts between the SCMs and the guideway, is also considered in the model to improve the ride comfort.

Study on Electromagnetic Force Characteristics Acting on Levitation/Guidance Coils of a Superconducting Maglev Vehicle System

Superconducting Maglev has been developed as a high-speed transport system. Superconducting coils (SC coils) are installed on the vehicle, and levitation/guidance coils (LG coils) are installed on the ground. A null-flux-type electrodynamic suspension system provided by electromagnetic interaction between SC coils and LG coils serves as the levitation and guidance functions of the vehicle system. Electromagnetic forces acting on SC coils are related to levitation and guidance functions of the vehicle. These forces were studied in previous research, and characteristics of levitation and guidance forces were revealed with respect to parameters of the design of the vehicle. On the other hand, electromagnetic forces acting on LG coils also exist as action–reaction pairs with the forces acting on SC coils. The forces act on LG coils in every levitated run of the vehicle, and stress is applied on the conductor and molded resin of the LG coils. In conventional studies, the vehicle design has been decided mainly by the electromagnetic forces acting on SC coils, and not by the forces acting on LG coils. The aim of the study is to establish an improved method to design the vehicle system with the objective of not only optimization of characteristics of the vehicle, but also consideration of stress on LG coils. As a preliminary study to establish the improved method, a study by computer simulation on characteristics of electromagnetic forces acting on LG coils with respect to the parameters of the vehicle is described in this paper.

Results of Vibration Control of a Maglev Vehicle Utilizing a Linear Generator

To make the superconducting magnetically levitated transport (maglev) system more attractive, it has been important to enhance the ride comfort by controlling vehicle vibration. Maglev vehicle vibrations have been reduced in previous experiments by controlling only the secondary suspension between the car bodies and bogies. However, by doing so, it has been difficult to reduce vibration for the characteristic and relatively high frequencies of the primary suspension between the bogies and guideway. Recently, control of the primary suspension is being considered. Power collecting coils of a linear generator system, which is being tested as an onboard power source, can also generate additional forces that can be used to control vibrations. Because this type of vibration control can apply damping directly to the primary suspension, it can reduce vibrations of relatively higher frequencies that are difficult to reduce by controlling only the secondary suspension. A maglev vehicle model that focuses on vertical and pitching motions is used to examine the effectiveness of reducing vibrations by using a linear generator damping force control in the primary suspension and linear quadratic (LQ) control of the actuators in the secondary suspension. Experimental results using the linear generator on a full-scale maglev vehicle on the Yamanashi Maglev Test Line are described.Copyright