Jeong-Min Jo

Analysis on the half bridge resonant DC to DC converter for electrical multiple units train set

The half bridge series resonant converter used for low output voltage power supply applications. This system has soft switching implementation without additional device, high efficiency and compact control. These advantages make this converter promising for high power applications such as auxiliary power supply in the EMU train set. The system consists of hard switched boost chopper, soft switched high frequency inverter based on split capacitors in DC link, high frequency transformer and rectifier. This paper describes several aspects relating to the design of resonant DC/DC converter operating at high frequency and converter topologies are discussed. Simulation and Experiment are performed. These results show that the power electronics converter using resonance DC-DC converter is feasible to the power supply system for EMU train set.

Development of the linear synchronous motor propulsion testbed for super speed maglev

For the development of a super speed maglev train with 500km/h level, the high power and efficient linear synchronous motor(LSM) as a propulsion device is necessary. To control the LSM, the precise position information of maglev must be detected and transmitted to the inverter controller which provides the synchronized power to the LSM stator attached on the guideway. To minimize the power input to the stator, the whole guideway is devided into several sections and the power is supplied to the only one section which the train is running on. In this case, precise section change control is needed to mitigate the vibration and noise. In this study, to evaluate and test the control technologies for super speed maglev, the infinite loop type LSM testbed is developed.

Investigation on stray magnetic field of high speed maglev

Magnetic fields (MF) generated both on board the vehicle and along the guideway provide levitation and propulsion forces. High speed maglev trains adopt electromagnet or superconducting magnet to realize levitation and propulsion functions. However, stray fields existing in passenger compartment and regions surrounding the vehicle and guideway have effect on passengers and environment. To investigate stray magnetic field effect, model of Transrapid and MLX are studied.

Study on the effectiveness of high-speed railway communication and signaling system based on 4G LTE technology

Due to speed acceleration, higher requirements have been put forward to high speed railway communication and signaling system. The railway applications, including intra-train, train to ground and trackside networks, demand larger bandwidth, higher reliability and shorter response time from railway communication networks to ensure security operation and passenger communication. However, the current railway communication and signaling system has lagged behind the railway development, so advanced communication technologies are needed to improve the current situation. This paper presents high speed railway communication and signaling system based on 4G LTE technology, introduces its network architecture, key technology and analyzes its technical advantages compared with GSM-R system. According to analysis, LTE based high-speed railway communication network is more effective and reliable.

A Study on Trend of Technology Development for Super-Speed Maglev

In this study, to understand the technology development trend of super-speed maglev, the patents applied by major countries are analyzed. And based on the analyzed results, the domestic technology development direction are suggested. For patent analysis, the major technologies for super-speed maglev are classified into 14 parts. Then, through the quantitative analysis method such as number, increase rate and share rate, the overview of technology development and focused parts by each country are investigated. Also through the qualitative analysis method such as concentration degree, citation index and market share index, the technology level and market securing ability of each country are anticipated. Considering the analyzed results and technology development trend, the domestic technology development direction such as priority development fields and methods are proposed.

Thrust Performance Improvement through Position Signal Compensation and Estimation in Super Speed Maglev

In position detection for super speed maglev propulsion control, the influence of position signal delay and transmit cycle on propulsion power degradation is investigated analytically and validated by test bed experiments. As a solution to the problem caused by signal transmit, position signal compensation and estimation method is proposed and applied to the test bed. Through experiments, it is confirmed that by adapting the proposed method, the propulsion power is increased remarkably, which results in acceleration and velocity performance improvement. This method could be effectively applied to position detection system of Korean super speed maglev which is under development.

Analysis of the influence of magnetic stiffness on running stability in a high-speed train propelled by a superconducting linear synchronous motor

There are two major obstacles that prevent a conventional train from achieving high speed: the limitation of wheel–rail adhesion and the increase of instability in the wheel–rail running dynamics. To overcome these problems, a new hybrid train model is introduced in this study. This train utilizes a superconducting linear synchronous motor (SC-LSM), instead of a traction motor, for propulsion; therefore, this train does not have the limitation of adhesion between the wheel and the rail. Using an SC-LSM also improves the stability of the train during high-speed operations. The magnetic stiffness between the train and the guideway is additionally generated by using the SC-LSM, which is favorable for the running stability at a high speed. This study focuses on the magnetic stiffness and its effect on the running stability in the proposed hybrid train model. First, the magnetic stiffness in the SC-LSM is investigated both theoretically and experimentally. Then, a train dynamic model including the magnetic stiffness is developed and the effect of magnetic stiffness on the running stability is analyzed through various simulations.

Dynamic Analysis of Wheel-Rail High Speed Train Propelled by Superconducting Linear Synchronous Motor

This study examined the running dynamic characteristics of a hybrid type wheel-rail high speed train, in which the propulsion method of maglev is applied. A wheel-rail high speed train propelled by a superconducting linear synchronous motor (SC-LSM) is expected to be superior to a maglev train regarding economical and interoperable aspects, still having powerful thrust force as maglev. In this paper, regarding the two methods of applying the SC-LSM to an existing wheel-rail train, to investigate the influences of SC-LSM propulsion on the dynamic characteristics of wheel-rail high speed train, the dynamic model of train including interaction between the rotor and stator of SC-LSM is established. Through the simulation using the model, the influence of the interaction between the rotor and stator of SC-LSM on stability, ride comfort and the effect of guideway irregularity are investigated.

Design of DC-DC Converter to Charge and Discharge Ultra-Capacitor Modules for Wireless Trains

Electric power trains receive electric power from overhead cables via a pantograph system. Power collector system in trains increase the cross section of tunnel and require a massive coreless filter reactor in propulsion inverter because of the power disturbance by contact loss phenomenon of a train. In this paper we proposed a wireless train which can run to next station with charging energy of ultra-capacitor module block. We designed DC-DC converter to charge and discharge ultra-capacitor modules by using Next Train running test results and confirm the feasibility of the proposed system through simulation.

The Trend Analysis of Technology Development for Auxiliary Power Supply of Electric Vehicle

RD transformer can be classified into high frequency transformer, ferrite transformer and matching transformer. By analyzing R&D trend of different counties, companies and years, specific technology needed to be developed and trend of technology can be accurately grasped.