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Miller, John M

Publications and source records attributed to Miller, John M.

8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Graphene-coated coupling coil for AC resistance reduction

At least one graphene layer is formed to laterally surround a tube so that the basal plane of each graphene layer is tangential to the local surface of the tube on which the graphene layer is formed. An electrically conductive path is provided around the tube for providing high conductivity electrical path provided by the basal plane of each graphene layer. The high conductivity path can be employed for high frequency applications such as coupling coils for wireless power transmission to overcome skin depth effects and proximity effects prevalent in high frequency alternating current paths.

42 ENGINEERING↗
DOE OSTI2014

Dynamic Wireless Charging of Electric Vehicle Demonstrated at Oak Ridge National Laboratory: Benefit of Electrochemical Capacitor Smoothing

Abstract Wireless charging of an electric vehicle while in motion presents challenges in terms of low latency communications for roadway coil excitation sequencing, and maintenance of lateral alignment, plus the need for power flow smoothing. This paper summarizes the experimental results on power smoothing of in-motion wireless EV charging performed at Oak Ridge National Laboratory using various combinations of electrochemical capacitors at the grid-side and in-vehicle. Electrochemical capacitors of the symmetric carbon-carbon type from Maxwell Technologies comprised the in-vehicle smoothing of wireless charging current to the EV battery pack. Electro Standards Laboratories fabricated the passive and active parallel lithium-capacitor unit used to smooth grid-side power. Power pulsation reduction was 81% on grid by LiC, and 84% on vehicle for both lithium-capacitor and the carbon ultracapacitors.

Miller, John M↗
DOE OSTI2013

Oak Ridge National Laboratory Wireless Power Transfer Development for Sustainable Campus Initiative

Wireless power transfer (WPT) is a convenient, safe, and autonomous means for electric and plug-in hybrid electric vehicle charging that has seen rapid growth in recent years for stationary applications. WPT does not require bulky contacts, plugs, and wires, is not affected by dirt or weather conditions, and is as efficient as conventional charging systems. This study summarizes some of the recent Sustainable Campus Initiative activities of Oak Ridge National Laboratory (ORNL) in WPT charging of an on-campus vehicle (a Toyota Prius plug-in hybrid electric vehicle). Laboratory development of the WPT coils, high-frequency power inverter, and overall systems integration are discussed. Results cover the coil performance testing at different operating frequencies, airgaps, and misalignments. Some of the experimental results of insertion loss due to roadway surfacing materials in the air-gap are presented. Experimental lessons learned are also covered in this study.

EV↗
DOE OSTI2013

Single-Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance. To understand the power flow through the system this paper presents a novel approach to the system model and the impact of different control parameters on the load power. The implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation is also discussed.

PEV charging↗
DOE OSTI2013

A Compact Wireless Charging System for Electric Vehicles

In this paper, a compact high efficiency wireless power transfer system has been designed and developed. The detailed gate drive design, cooling system design, power stage development, and system assembling are presented. The successful tests verified the feasibility of wireless power transfer system to achieve over-all 90% efficiency.

inverter design↗
DOE OSTI2013

A Compact Wireless Charging System for Electric Vehicles

In this paper, a compact high efficiency wireless power transfer system has been designed and developed. The detailed gate drive design, cooling system design, power stage development, and system assembling are presented. The successful tests verified the feasibility of wireless power transfer system to achieve over-all 90% efficiency.

Ning, Puqi↗
DOE OSTI2013

Fabrication and Evaluation of a High Performance SiC Inverter for Wireless Power Transfer Applications

In this study, a high power density SiC high efficiency wireless power transfer converter system via inductive coupling has been designed and developed. The detailed power module design, cooling system design and power stage development are presented. The successful operation of rated power converter system demonstrates the feasible wireless charging plan. One of the most important part of this study is the wind bandgap devices packaged at the Oak Ridge National Laboratory (ORNL) using the in-house packaging technologies by employing the bare SiC dies acquired from CREE, which are rated at 50 A / 1200 V each. These packaged devices are also inhouse tested and characterized using ORNL s Device Characterization Facility. The successful operation of the proposed inverter is experimentally verified and the efficiency and operational characteristics of the inverter are also revealed.

Onar, Omer C↗