Karam Hwang

In-wheel motor application in a 4WD electric vehicle with foldable body concept

With the growing concern on the environment and limited petroleum, the transportation field has been looking for alternative modes, vehicle segments, and improved operation strategies. On the other hand, with the growing transportation issues on urban applications in the trend of increasing numbers of mega cities and elderly populations, the personal mobility vehicle concept is being studied especially for the urban applications while maximizing the convenience of the users. This paper will introduce and review a conceptual prototype of personal mobility vehicles. The innovative design of an electric vehicle with a foldable concept will be introduced and discussed focused on the in-wheel motor assembly design and control of 4 wheel independent drive application. The required driving performance and dynamic characteristics of the vehicle are discussed and presented through the vehicle modeling considering the motor operation and control system design.

Autonomous Coil Alignment System Using Fuzzy Steering Control for Electric Vehicles with Dynamic Wireless Charging

An autonomous coil alignment system (ACAS) using fuzzy steering control is proposed for vehicles with dynamic wireless charging. The misalignment between the power receiver coil and power transmitter coil is determined based on the voltage difference between two coils installed on the front-left/front-right of the power receiver coil and is corrected through autonomous steering using fuzzy control. The fuzzy control is chosen over other control methods for implementation in ACAS due to the nonlinear characteristic between voltage difference and lateral misalignment distance, as well as the imprecise and constantly varying voltage readings from sensors. The operational validity and feasibility of the ACAS are verified through simulation, where the vehicle equipped with ACAS is able to align with the power transmitter in the road majority of the time during operation, which also implies achieving better wireless power delivery.

A Resonant Reactive Shielding for Planar Wireless Power Transfer System in Smartphone Application

Demand and interest in wireless power transfer (WPT) have been rapidly increasing lately. However, WPT systems have problems with electromagnetic field (EMF) leakage, which has stimulated interest in methods to suppress EMF leakage levels. In this paper, we propose a compact resonant reactive shielding coil topology for reducing EMF in a near-field WPT mobile device application. The proposed shielding coil employs a closed loop and matching capacitors, and is demonstrated to dramatically reduce the leakage magnetic field from a WPT system. For validation, the proposed shielding was implemented with other shielding topologies and the EMFs were measured and compared. The analytical, simulation, and measurement results were all strongly correlated.

Development of a Foldable Micro Electric Vehicle for Future Urban Driving with Intelligent Control

There have been continuous efforts from global automotive industries with the new environmental regulations in order to reduce air pollution, to mitigate the global warming and to emphasize low carbon green growth. Micro mobility can be a new mode of transport that is being develop in order to provide a potential solution to the above issues. This paper introduces the foldable micro electric vehicle and focuses on prototype design and control architecture of that. The innovative design of folding mechanism and the motor control system without position sensing is proposed. This method uses current information from Energy Management System (EMS) to estimate position of the folding motor. In-wheel drive control system for micro mobility is proposed.

Pickup Coil Counter for Detecting the Presence of Trains Operated by Wireless Power Transfer

An axle counter is a popularly used device for detecting passing trains. They detect train wheels by the change of the magnetic field, made by the train wheels, in a receiving coil. Wireless power transfer (WPT) systems are used to deliver tractive power to electric trains by magnetic resonance. They consist of a pickup coil onboard the train, a supply coil on the track, and related trackside electronic circuits. When a WPT system is proximate to an axle counter, the magnetic field of the WPT can produce significant electromagnetic interference, significantly affecting the performance of the axle counter. Since the WPT system is an emerging power supply system for future railways, an alternative device for detecting trains is considered necessary. A novel device called the pickup coil counter (PCC) is proposed for this purpose. Unlike the axle counter, which detects the train’s wheels, the PCC detects the WPT pickup coil onboard the train using a sensor coil wound around the WPT supply coil on the track and a detection circuit in trackside equipment. The operating concept of the PCC is explained. Its detection performance was evaluated by 3-D FEM simulation and experiment, and the results are presented.

Smart Mobility Strategy in Korea on Enhanced Safety and Higher Capacity Toward 2025

Surface transportation system encounters strong demand on improved safety, lesser traffic congestion and enhanced throughputs which lead to endless and continuous innovation on vehicular technologies. Integrating existing and emerging technologies, with minimized infrastructure investment, while achieving the most efficient transportation system, in view of safety, throughputs and required conveniences, has been a core activity of intelligent transportation system (ITS) planning and implementation. In Korea, a strategic planning has been performed targeted to 2025 in order to enhance safety and throughputs integrating various intelligent vehicular technologies and accommodating automated vehicle concept, of which core approaches are described in this paper. Based upon the survey on various test-bed development and implementation in Europe, US and other countries, the strategic planning on technology roadmap and test-bed application with core technology elements by identifying and prioritizing the demand are described and discussed, especially emphasized on combining communication technology with vehicle and infrastructure. In addition, cooperative and simultaneous application of vehicle and infrastructure technologies is emphasized for efficient future mobility by proposing a strategic approach under the project named as a `Smart Mobility.

Miniaturization of Implantable Micro-Robot Propulsion Using a Wireless Power Transfer System

Recently implantable micro-robots have been researched actively in the means of medical application. This micro-robot can be used for localized delivery and various forms of energy. Targeted drug delivery increases the concentration of drug in region of interest and reduce the risk of side effects in the rest of the body. In addition, the micro-robot can delivery heat energy to destroy unwanted cells and collect the images inside of the body to make an accurate diagnosis. Currently, most of research are use static magnet inside of micro-robot to generate propulsion force. This kinds of micro-robot can be implemented as nano-size, but the utilization of these are limited because of the it is not containing electrical energy source [1]. To receive the electrical energy, the micro robot using wireless power transfer system have been proposed. Unlikely conventional research which using motor actuator, generate propulsion using Lorentz force is pronounced [2].

High-Efficiency Wireless Power and Force Transfer for a Micro-Robot Using a Multiaxis AC/DC Magnetic Coil

In this paper, a high-efficiency wireless power transfer (WPT) and force transfer system for a micro-robot is proposed. Two-coil systems are employed to power the micro-robot. The two-coil parts are ac and dc, and each consists of an external source and a load coil inside the micro-robot. In the ac coil part, the external source coil generates a time-varying magnetic field that is received by the ac load coil in the micro-robot as electrical energy. In the dc coil part, the external source coil is used as an electromagnet, which is used to generate propulsion force for the micro-robot. Through the proposed system, both the efficiency of electrical energy transfer and the generation of propulsion force can be significantly improved. The feasibility of the proposed approach was verified through simulation and experimentation results.

Generating propulsion force in micro-robot using wireless power transfer system

In this paper, a micro-robot capable of receiving both electrical energy and mechanical energy is proposed. The electrical energy is transferred using wireless power transfer system, and the mechanical energy is represented as propulsion force. To generate Lorentz force which is the source of propulsion force, the phase difference between source current and load current are controlled by changing capacitance to avoid LC resonance. These proposed concepts are explained with theoretical analysis and validated by simulation results.

An Improved 100 GHz Equivalent Circuit Model of a Through Silicon Via With Substrate Current Loop

This letter presents a new wideband equivalent circuit model for through silicon via (TSV) with consideration of the effective substrate current loop in silicon substrate and proximity effect on the currents in the TSV. The proposed model can accurately predict the electrical performance of the TSV at wide frequency range. The proposed model correlates well up to 100 GHz when compared to the full-wave electromagnetic simulation.