Electric power

About: Electric power is a research topic. Over the lifetime, 73036 publications have been published within this topic receiving 636991 citations.

Oil well casting electrical power pick-off points

Abstract: A power supply apparatus is provided for supplying power and communications within a first piping structure. An external power transfer device is positioned around the first piping structure and is magnetically coupled to an internal power transfer device. The internal power transfer device is positioned around a second piping structure disposed within the first piping structure. A main surface current flowing on the first piping structure induces a first surface current within the external power transfer device. The first surface current causes a second surface current to be induced within the internal power transfer device.

Ultracapacitor technologies and application in hybrid and electric vehicles

Abstract: This paper focuses on ultracapacitors (electrochemical capacitors) as energy storage in vehicle applications and thus evaluates the present state-of-the-art of ultracapacitor technologies and their suitability for use in electric and hybrid drivelines of various types of vehicles. A key consideration in determining the applicability of ultracapacitors for a particular vehicle application is the proper assessment of the energy storage and power requirements. For hybrid–electric vehicles, the key issues are the useable energy requirement and the maximum pulse power at high efficiency. For a Prius size vehicle, if the useable energy storage is about 125 Wh and needed efficiency is 90–95%, analysis shown in this paper indicate that vehicles can be designed using carbon ultracapacitors (both carbon/carbon and hybrid carbon) that yield high fuel economy improvements for all driving cycles and the cost of the ultracapacitors can be competitive with lithium-ion batteries for high volume production and carbon prices of less than $20 kg−1. The use of carbon/carbon devices in micro-hybrids is particularly attractive for a control strategy (sawtooth) that permits engine operation near its maximum efficiency using only a 6 kW electric motor. Vehicle projects in transit buses and passenger cars have shown that ultracapacitors have functioned as expected and significant fuel economy improvements have been achieved that are higher than would have been possible using batteries because of the higher round-trip efficiencies of the ultracapacitors. Ultracapacitors have particular advantages for use in fuel cell powered vehicles in which it is likely they can be used without interface electronics. Development of hybrid carbon devices is continuing showing energy densities of 12 Wh kg−1 and a high efficiency power density of about 1000 W kg−1. Vehicle simulations using those devices have shown that increased power capability in such devices is needed before full advantage can be taken of their increased energy density compared with carbon/carbon devices in some vehicle applications. Energy storage system considerations indicate that combinations of ultracapacitors and advanced batteries (Wh kg−1>200) are likely to prove advantageous in the future as such batteries are developed. This is likely to be the case in plug-in hybrids with high-power electric motors for which it may be difficult to limit the size and weight of the energy storage unit even using advanced batteries. Copyright © 2009 John Wiley & Sons, Ltd.

Electric power supply system and vehicle

Abstract: An electric automobile has a battery and also has a travel motor and a vehicle interior load device which operate using electric power from the battery. In response to a request for a start of electric power supply to the vehicle interior load device with the automobile being at a standstill, the electric automobile determines, based on the charged state of the battery, whether electric power from the battery can be supplied to the vehicle interior load device. When determining that the electric power from the battery cannot be supplied to the vehicle interior load device, the electric automobile makes a request to an electric power supply device to supply electric power to the vehicle interior load device. In response to the request, the electric power supply device electrically connects to the vehicle interior load device and starts supply of electric power to the vehicle interior load device.

Practical roadmap and limits to nanostructured photovoltaics.

Abstract: The significant research interest in the engineering of photovoltaic (PV) structures at the nanoscale is directed toward enabling reductions in PV module fabrication and installation costs as well as improving cell power conversion efficiency (PCE). With the emergence of a multitude of nanostructured photovoltaic (nano-PV) device architectures, the question has arisen of where both the practical and the fundamental limits of performance reside in these new systems. Here, the former is addressed a posteriori. The specific challenges associated with improving the electrical power conversion efficiency of various nano-PV technologies are discussed and several approaches to reduce their thermal losses beyond the single bandgap limit are reviewed. Critical considerations related to the module lifetime and cost that are unique to nano-PV architectures are also addressed. The analysis suggests that a practical single-junction laboratory power conversion efficiency limit of 17% and a two-cell tandem power conversion efficiency limit of 24% are possible for nano-PVs, which, when combined with operating lifetimes of 10 to 15 years, could position them as a transformational technology for solar energy markets.