This paper proposes an all-in-one system for hyperloop that conducts propulsion, levitation, and guidance. Currently demand on high-speed long-distance transportation is increasing, so that hyperloop is getting attention and studied hard globally. Hyperloop is a new innovative transportation in which a levitated subsonic speed train travels through a vacuum cylindrical tube. Hyperloop needs functions of propulsion, levitation, and guidance for its service, and many devices are necessary for those functions. In the tube, a constrained space, many devices make the entire system complicated, and the size of the vehicle and tube are increased. Therefore, the costs of maintenance, manufacture, and construction are increased and control of each device becomes very difficult. But a non-symmetric double-sided linear induction motor (NSDLIM), the subject of this paper, is an all-in-one system that could conduct all functions. In this paper, the concept of NSDLIM was introduced and its possibility was suggested. Requirements of NSDLIM were investigated considering very high acceleration, velocity, and low air pressure. An NSDLIM model was designed and analyzed by using the finite-element method. Then, NSDLIM parameters that affect performance were investigated and adjusted to improve performance. The derived model performance was shown, and its possibility was considered.

This paper is a study on the application position of skew in order to reduce the cogging torque of a magnetic geared synchronous motor (MGM). The cogging torque affects the noise and vibration of the motor, so it should be reduced as much as possible. To solve this problem, a conventional permanent magnet (PM) synchronous motor is skewed to a PM. However, unlike other synchronous motors, the MGM has pole pieces (PPs), and a larger cogging torque is generated due to a larger reluctance difference. There have been few studies on the reduction of cogging torque of MGM, so it is essential to study the skew structure of MGM. Therefore, this paper has derived the optimum skew method by comparing and analyzing three models of MGM skewed to PM, PP, and PM and PP simultaneously.

In this paper, a 600-km/h-class high-speed train with wheel-rail support and a linear synchronous motor (LSM) propulsion system is being considered. Prior to the development of superconducting LSM for propulsion of 600-km/h-class high-speed trains, preperformance validation through a small-scale prototype is required. Therefore, a small-scale 7-kW-class superconducting air-core-type LSM prototype was designed, one that includes a superconducting magnet with two poles. High-temperature superconducting wire of the Gd-Ba-Cu-O series was used for the magnet. Next, the various characteristics of the designed model were estimated through a numerical approach, with the finite element method. Finally, a small-scale superconducting LSM prototype was produced and installed in a bogie on a 10-m track. A performance test of the superconducting magnet and a no-load induced voltage and thrust measurement test of the small-scale superconducting LSM were completed. The effectiveness of the proposed superconducting LSM design techniques and design model was verified.

This paper reports the design of a magnetic-geared permanent magnet synchronous motor (MG-PMSM) for a 45 kW tram traction system based on high torque density. In the case of the existing tram driving system, due to mechanical reduction gear and induction motor, it causes power transmission loss, low efficiency, and difficulty in lightweight. To solve this problem, research on the MG-PMSM, which combines a contactless magnetic gear with a high-power-density PMSM, is being actively conducted. This motor has a double rotor structure, and the inner rotor, including permanent magnet, and the outer rotor composed of pole-pieces rotate at different mechanical speeds. However, it is hard to design a tram driving system with a high torque density within limited conditions, because only one rotor in MG-PMSM is used as an output. In addition, there is no study conducted from basic design to final design, including gear ratio and topology selection in MG-PMSM for tram. Therefore, this paper presents the design process of MG-PMSM with high torque density to be applied to the 45 kW–class tram driving system. After designing the magnetic gear part that increases torque and efficiency by selecting an appropriate topologies-and-gear ratio that meets the constraints, the final finite elements method (FEM) model and electromagnetic field analysis results were derived by considering the number of poles and the number of slots. Through this, we confirmed that it is superior in output characteristics compared to the existing induction motor + mechanical gear.

In this paper, to complement the capability of the existing heating system using an electric-heating wire for melting snow and ice in railway turnouts, 250kHz-200W-class Induction Heating (IH) system was designed. The IH system consists of the resonant inverter and the IH device. In order to perform the electric circuit, the electromagnetic field, and the thermal analysis, the Multi-Physics analysis for IH system was derived. In addition, IH system was compared with the existing heating system.

Generally, the DC-DC converters used in DC fast chargers must cover a wide output voltage with a fixed input voltage, and a single module needs to supply 30-50 kW of power. When designing an LLC resonant converter to cover a wide output voltage with a narrow frequency at high power, a small magnetizing inductance is required, resulting in increased switching turn-off losses. Additionally, a large air gap in the transformer is needed, which increases AC losses in the transformer windings owing to the fringing effect, degrading efficiency. Therefore, to cover a wide output voltage with a fixed input voltage while achieving high power and efficiency, the LLC resonant converter followed by the buck converter is proposed in this paper. Because the LLC resonant converter operates at a fixed frequency, a large magnetizing inductance can be used. This results in lower switching turn-off losses and a smaller air gap in the transformer, which decreases AC losses in the transformer windings. Additionally, by optimally selecting the frequencies of each converter and output voltage of the LLC resonant converter, which functions as the input voltage of the buck converter, high efficiency can be achieved. To confirm the validity of the proposed structure of the DC-DC converter, an 820 V input and 150-1,000 V/50 kW output prototype is built and tested.