Chan-Bae Park

Development of 1-MW Inductive Power Transfer System for a High-Speed Train

Design and fabrication of a 1-MW inductive power transfer (IPT) system that supplies power to the vehicle in real time without any battery charge is proposed for a high-speed train. The IPT system consists of a 1-MW resonant inverter, a 128-m transmitter, four pickups, including rectifiers, and a wireless feedback network to maintain a constant output voltage of the pickups. The operating frequency of the system is 60 kHz to achieve efficient power transfer with a large air gap. The measured efficiency of the IPT system at the 818-kW output power of the pickups for the 5-cm air gap is 82.7%. The electromagnetic field and the induced voltage at the rail are also measured for safety evaluation. The fabricated IPT system was adapted to the high-speed train, and the train successfully accelerates to a speed of 10 km/h according to startup procedures.

A study on the Reduction of the Stator iron loss on Permanent Magnet Synchronous Motor for Light Railway Transit Propulsion System

A study on the iron-loss reduction of 110kW-class Interior Permanent Magnet Synchronous Motor (IPMSM) for Light Railway Transit (LRT) is conducted. In general, the iron loss of IPMSM depends on the characteristics of core material and non-oriented electrical steel is used as a core material of IPMSM. In order to reduce the iron-loss of IPMSM, both non-oriented electrical steel and grain oriented electrical steel are applied as core material. Iron loss of 110kW-class IPMSM can be reduced approximately 40% comparing to an existing IPMSM by applying grain oriented electrical steel to the stator teeth.

Investigation of a Thermal Analysis Method for IPMSM in Railway Vehicles

In this paper, research on the thermal analysis method is reported for the characterization of heat generation while operating an Interior Permanent Magnet Synchronous Motor (IPMSM) for railway vehicles. Efficient cooling of the heat generated in the IPMSM is important because the excessive heat generated from the winding, core and permanent magnets increases the difficulty of continuously operating an IPMSM over long time periods. Therefore, in this study, in order to analyze the heat generation characteristics of the IPMSM for advanced research in the application of IPMSMs to cooling devices, the heat transfer coefficients for each component of the IPMSM were derived and the thermal equivalent circuit was configured to perform thermal analyses. Finally, the validation of the suggested thermal analysis method was performed through comparison with the heat experimental data of an IPMSM prototype.

Development of a Small-Scale Superconducting LSM Using Gd-Ba-Cu-O High-Temperature Superconducting Wire

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.

Characteristic Analysis of Superconducting LSM for the Wheel-rail-guided Very High Speed Train according to Winding Method of the Ground 3-phase Coils

Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is based on wheel-rail method, but it enables to overcome the speed limitation by adhesion because it is operated by a non-contact method using a linear motor as a propulsion system and reduce the overall construction costs by its compatibility with the conventional railway systems. Therefore, the design and characteristic analysis of a coreless-type superconducting Linear Synchronous Motor (LSM) for 600km/h very high speed railway system are conducted in this paper. The designed coreless-type superconducting LSMs are the distributed winding model, the concentrated 1 layer winding model and the concentrated 2 layer winding model, respectively. In addition, the characteristic comparison studies on each LSM are conducted.

Core-loss Reduction on Permanent Magnet for IPMSM with Concentrated Winding

Interior Permanent Magnet Synchronous motors (IPMSM) with concentrated winding are superior to distributed winding in the power density point of view. But it causes huge amount of eddy current losses on the permanent magnet. This paper presents the optimal permanent magnet V-shape on the rotor of an interior permanent magnet synchronous motor to reduce the core losses and improve the performance. Each eddy current loss on permanent magnet has been investigated in detail by using FEM (Finite Element Method) instead of equivalent magnetic circuit network method in order to consider saturation and non-linear magnetic property. Simulation-based design of experiment is also applied to avoid large number of analyses according to each design parameter and consider expected interactions among parameters. Consequently, the optimal design to reduce the core loss on the permanent magnet while maintaining or improving motor performance is proposed by an optimization algorithm using regression equation derived and lastly, it is verified by FEM.

Analysis of Eddy Current Loss on Permanent Magnets of Interior Permanent Magnet Synchronous Motor for Railway Transit

In order to apply Interior Permanet Magnet Synchronous Motor(IPMSM) to the propulsion system of the railway transit, 110kW class IPMSMs with high-power density are designed as a concentrated winding model and a distributed winding model in this study. The concentrated winding model designed in this study is 6 poles/9 slots and the distributed winding model is 6 poles/36 slots. In general, the eddy current losses in the permanent magnets of IPMSM are caused by the slot harmonics. The thermal demagnetization of the magnet by the eddy current losses at high rotational speed often becomes one of the major problems in the IPMSM with a concentrated windings especially. A design to reduce eddy current losses in permanent magnet design is important in IPMSM for the railway vehicle propulsion system which requires high-speed operation. Therefore, a method to devide the permanent magnet is proposed to reduce the eddy current losses in permanent magnet in this study. Authors analyze the variation characteristics of the eddy current losses generated in permanent magnet of the concentrated winding model by changing the number of the division of the permanent magnets.

A Study on the Design of a 130kW-class IPMSM for Propulsion of Tram-Train

환경 문제와 더불어 도심 안에서의 교통수단뿐만 아니라, 도심과 도심을 연결하는 교통수단으로도 철도시스템이 주목받고 있 다. 특히 일반 도로에서 자동차와 함께 운행 가능하면서 건설비도 상대적으로 적은 트램 규모의 철도차량을 활용한 트램-트레 인 시스템은 향후 도심의 교통 문제를 해결해 줄 유력한 방안 중의 하나이다. 트램-트레인의 개념은 철도 차량이 두 가지 운행 모드 즉, 도심 센터를 운행하는 트램 기능과 기존의 도시 간 지역철도 네트워크를 서비스하는 통근열차로 동시에 운행하는 시 스템이다. 이러한 이중 운행방식 개념은 상당한 운영 탄력성과 철도인프라 시설과 연결지점의 효율적인 사용을 제공한다. Fig. 1은 세계의 대표적인 트램-트레인 차량을 보여준다. Fig. 1(a)는 영국의 셰필드-로더럼 구간을 2017년도부터 운행 예정인 트램트레인 차량으로써, Vossloh에서 제작하였으며, 최고 운영속도는 110km/h이다. Fig. 1(b)는 독일 Karlsruhe 시내와 교외 구간를 운영 중인 트램-트레인 차량으로써, 최고 운영속도는 100km/h이다. 트램-트레인은 도심 안에서뿐만 아니라 도시와 도시간의 연 결 교통수단으로 활용이 가능하므로 차량의 경우 100km/h 이상의 주행이 가능한 준고속열차의 성능을 보유하여야 한다. 따라 서 도심 안에서의 저속운전 및 도시간 이동 시의 고속운전이 모두 가능한 추진시스템의 개발이 필수적으로 요구된다. 기존 철도차량 견인용 전동기는 전력용 반도체 및 제어 기술의 발달에 따라 직류전동기에서 유도전동기로 획기적인 발전을 이루어 기술적 완성단계에 진입하였다. 그러나 최근 높은 에너지 밀도를 가지는 희토류계 영구자석이 개발되면서 기존의 유도 전동기보다 효율과 출력밀도가 향상된 매입형 영구자석 동기전동기(Interior Permanent Magnet Synchronous Motor, 이하 IPMSM)가 상당수 개발되었다. 이러한 IPMSM은 높은 효율과 약자속 제어를 통한 넓은 속도 가변 영역 특성을 갖는다. 이러한 Abstract This study considers the design of a 130kW-class IPMSM for propulsion of a Tram-Train. This Tram-Train has a wide range of speed variation. For this reason, this study suggested IPMSM, which has wide speed variation as a motor for propulsion of the Tram-Train, a basic model suitable for the required traction force was designed. IPMSM has different electromagnetic and structural characteristics depending on the shapes of its rotor. Therefore, the suggested model was additionally designed, and by dividing a permanent magnet was changed so as th have a shape with an added bridge. Finally, by analyzing the load characteristics with finite element analysis of the basic and suggested models and by comparing electromagnetic and structural characteristics, a model has been derived that satisfies IPMSM for the propulsion of the Tram-Train.

A new design methodology for a 300 kW, low flux density, large air-gap, on-line wireless power transfer system

A high power on-line wireless power transfer system has been investigated intensively in recent years. However, no literature has focused on the design methodology of the high power on-line wireless power transfer system with low flux density, high efficiency, and high control stability. This paper proposed a new design methodology for a 300 kW, over 96%coil-to-coil efficiency, ICNIRPs safety regulation compatible on-line wireless power transfer system. Using a finite element analysis and experimental results, the proposed design methodology has been evaluated.

Simulation based Comparative Loss Analysis and Output Characteristic for 25MW Class of High Power Multi-level Inverters

The multi-level inverters are highly efficient for high-power and medium-voltage AC driving applications, such as high-speed railway systems and renewable energy resources, because such inverters generate lower total harmonic distortion (THD) and electromagnetic interface (EMI). Lower switching stress occurs on switching devices compared with conventional two-level inverters. Depending on the multi-level inverter topology, the required components and number of switching devices are different, influencing the overall efficiency. Comparative studies of multi-level inverters based on loss analysis and output characteristic are necessary to apply multi-level inverters in high-power AC conversion systems. This paper proposes a theoretical loss analysis method based on piecewise linearization of characteristic curves of power semiconductor devices as well as loss analysis and output performance comparison of five-level neutral-point clamped, flying capacitor inverters, and high-level cascaded H-bridge multi-level inverters.