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This paper presents numerical analysis and design of high power contactless transformer with a large air-gap for moving on a guided linear track which is appropriate for high-speed train or MAGLEV. The system has the typical characteristics of large leakage inductance, small magnetizing inductance, and low coupling coefficients giving rise to lower power transfer efficiency, which have been compensated by the purposely-designed contactless transformer coupled with the resonant converter modulating with high switching frequency. In particular, the best model selected from the generated six design candidates has been applied for 3D Finite Element Analysis (FEA) investigating on iron loss to evaluate the overall system efficiency.

This paper presents contactless power supply systems using Valtchev model in transportation systems. The major drawback of contactless systems is that the efficiency is lower than that of contact systems. The coupling coefficient of the contactless transformer is the most influent parameter on the system efficiency. Here, a new computer model for the contactless transfer system developed in the Korea Railroad Research Institute is present. Also, simulations of the old model and the new model are compared with the prototype measurement to assure the model validity.

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-Contactless systems use electromagnetic fields to transport power from railway substation to the traction system. The proto type of inductive power transfer (IPS) system has been developed in order to use train power feeding. It is based on a contactless transformer with a fixed coreless primary and different secondary core like E shape and U shape. The primary coil is supply with 50 kHz current which produces a magnetic flux in the secondary core. Further this flux induces a current in the secondary coil. This paper presents results of experiment for developed inductive power transfer system experiments. The IPS has a large air gap, so it is required a high magnetization current and compensate the leakage flux of primary and secondary coil. The proto type IPS has an air gap with range 1 to 5 mm and core material is ferrite with maximum power of 5 kW. The power supply to IPS is designed by constant current control inverter with compensation capacitance. We measure inductance of IPS and coupling coefficient in order to calculate the compensation parameter according to variable air gap. The analysis of output for the proto type IPS is performed regarding different loads.

The high-power wireless power transfer (WPT) system in railways does not require physical contact to transfer electrical power, is electrically safe, and reduces maintenance costs from wear and tear. However, a high-power system generates a strong magnetic field that can result in problems of electromagnetic field (EMF) exposure and electromagnetic interference (EMI). In this study, EMF and EMI were measured at various positions under in-motion environment conditions for a 1-MW WPT light rail transit system. The measured maximum EMF was 2.41 μT, which is lower than the international guideline of 6.25 μT for the various locations with a potential presence of passengers. The measured EMI also satisfied international standards in the frequency range of 150 kHz–1 GHz.

This paper proposes two different types of core shape analysis for contactless transformer, which can be used for delivering high-power to traction in new railway systems. This type of railway system without catenary can save construction cost and maintenance costs. The major problem of contactless transformer is the air gap between the primary side and secondary side, which affects the power delivery. To enhance power delivery, the proposed shapes are installed and tested for with prototype. The two results are compared by the measurement of the self-inductances, mutual inductances and the coupling coefficient, with the analysis of the assembly process.I.