The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

This paper reviews the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in electric vehicles and hybrids. Charger systems are categorized into off-board and on-board types with unidirectional or bidirectional power flow. Unidirectional charging limits hardware requirements and simplifies interconnection issues. Bidirectional charging supports battery energy injection back to the grid. Typical on-board chargers restrict power because of weight, space, and cost constraints. They can be integrated with the electric drive to avoid these problems. The availability of charging infrastructure reduces on-board energy storage requirements and costs. On-board charger systems can be conductive or inductive. An off-board charger can be designed for high charging rates and is less constrained by size and weight. Level 1 (convenience), Level 2 (primary), and Level 3 (fast) power levels are discussed. Future aspects such as roadbed charging are presented. Various power level chargers and infrastructure configurations are presented, compared, and evaluated based on amount of power, charging time and location, cost, equipment, and other factors.

/pdf/review-of-battery-charger-topologies-charging-power-levels-85yy2igx2w.pdf

Review of Battery Charger Topologies, Charging Power Levels, and Infrastructure for Plug-In Electric and Hybrid Vehicles

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30 years with the term inductive power transfer. WPT technology is developing rapidly in recent years. At kilowatts power level, the transfer distance increases from several millimeters to several hundred millimeters with a grid to load efficiency above 90%. The advances make the WPT very attractive to the electric vehicle (EV) charging applications in both stationary and dynamic charging scenarios. This paper reviewed the technologies in the WPT area applicable to EV wireless charging. By introducing WPT in EVs, the obstacles of charging time, range, and cost can be easily mitigated. Battery technology is no longer relevant in the mass market penetration of EVs. It is hoped that researchers could be encouraged by the state-of-the-art achievements, and push forward the further development of WPT as well as the expansion of EV.

Wireless Power Transfer for Electric Vehicle Applications

The fuel economy and all-electric range (AER) of hybrid electric vehicles (HEVs) are highly dependent on the onboard energy-storage system (ESS) of the vehicle. Energy-storage devices charge during low power demands and discharge during high power demands, acting as catalysts to provide energy boost. Batteries are the primary energy-storage devices in ground vehicles. Increasing the AER of vehicles by 15% almost doubles the incremental cost of the ESS. This is due to the fact that the ESS of HEVs requires higher peak power while preserving high energy density. Ultracapacitors (UCs) are the options with higher power densities in comparison with batteries. A hybrid ESS composed of batteries, UCs, and/or fuel cells (FCs) could be a more appropriate option for advanced hybrid vehicular ESSs. This paper presents state-of-the-art energy-storage topologies for HEVs and plug-in HEVs (PHEVs). Battery, UC, and FC technologies are discussed and compared in this paper. In addition, various hybrid ESSs that combine two or more storage devices are addressed.

Battery, Ultracapacitor, Fuel Cell, and Hybrid Energy Storage Systems for Electric, Hybrid Electric, Fuel Cell, and Plug-In Hybrid Electric Vehicles: State of the Art

Various noncontacting methods of plug-in electric vehicle charging are either under development or now deployed as aftermarket options in the light-duty automotive market. Wireless power transfer (WPT) is now the accepted term for wireless charging and is used synonymously for inductive power transfer and magnetic resonance coupling. WPT technology is in its infancy; standardization is lacking, especially on interoperability, center frequency selection, magnetic fringe field suppression, and the methods employed for power flow regulation. This paper proposes a new analysis concept for power flow in WPT in which the primary provides frequency selection and the tuned secondary, with its resemblance to a power transmission network having a reactive power voltage control, is analyzed as a transmission network. Analysis is supported with experimental data taken from Oak Ridge National Laboratory’s WPT apparatus. This paper also provides an experimental evidence for frequency selection, fringe field assessment, and the need for low-latency communications in the feedback path.

Primary-Side Power Flow Control of Wireless Power Transfer for Electric Vehicle Charging

Modeling, control and simulation of a PV/FC/UC based hybrid power generation system for stand-alone applications

Solar Energy Harvesting Introduction I-V Characteristics of Photovoltaic (PV) Systems PV Models and Equivalent Circuits Sun Tracking Systems MPPT Techniques Shading Effects on PV Cells Power Electronic Interfaces for PV Systems Sizing the PV Panel and Battery Pack for Stand-Alone PV Applications Modern Solar Energy Applications Wind Energy Harvesting Introduction Winds History of Wind Energy Harvesting Fundamentals of Wind Energy Harvesting Wind Turbine Systems Wind Turbines Different Electrical Machines in Wind Turbines Synchronous Generators Wind Harvesting Research and Development Tidal Energy Harvesting Introduction Categories of Tidal Power and Corresponding Generation Technology Turbine and Generator's Control Tidal Energy Conversion Systems Grid Connection Interfaces for Tidal Energy Harvesting Applications Potential Resources Environmental Impacts Ocean Wave Energy Harvesting Introduction to Ocean Wave Energy Harvesting The Power of Ocean Waves Wave Energy Harvesting Technologies Wave Energy Applications Wave Energy in Future Ocean Thermal Energy Harvesting History Classification of Ocean Thermal Energy Conversions (OTECs) Technical Obstacles of Closed-Cycle OTEC Systems Components of an OTEC System Control of an OTEC Power Plant Control of a Steam Turbine Potential Resources Multipurpose Utilization of OTEC Systems Impact on Environment Index A Summary and References appear at the end of each chapter.

Energy Harvesting: Solar, Wind, and Ocean Energy Conversion Systems

As visionary as dynamic, or in-motion, wireless charging of electric vehicles appears the concept is well over a century old as this paper will show. This is because the concept of magnetic induction dates back to the pioneering work of physicist Michael Faraday in the early 19th century. Today wireless power transfer (WPT) is being standardized for stationary and quasi-stationary charging of electric vehicles (EV). The Society of Automotive Engineers (SAE) has undertaken the standardization of stationary charging and will make this public during 2016. In addition to this the IEEE-SA (Standards Activities) initiated standards development for EV?s in their EVWPT working group in 2012. This paper introduces the many challenges facing EVWPT in not only high power transfer to a moving vehicle and energy management at a utility scale, but communications in a vehicle to infrastructure (V2I) environment and management of high data rates, ultra-low latency, and dealing with communications loss in dense urban areas. Future concepts such as guideway powering of EV?s are presented to illustrate one technical trajectory EVWPT may take.

Omer C. Onar

Papers

Primary-Side Power Flow Control of Wireless Power Transfer for Electric Vehicle Charging

Modeling, control and simulation of a PV/FC/UC based hybrid power generation system for stand-alone applications

Energy Harvesting: Solar, Wind, and Ocean Energy Conversion Systems

ORNL Experience and Challenges Facing Dynamic Wireless Power Charging of EV's

Dynamic modeling, design and simulation of a wind/fuel cell/ultra-capacitor-based hybrid power generation system