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Pelotas, Brazil

Sam D.,PET
Power Electronics Technology | Year: 2011

Wind flow, or motion energy, activates wind turbines that generate electricity. In operation, wind turbines blades spin a shaft that connects to a generator and produces electricity for the utility grid. Wind turbines come in a variety of sizes and power ratings. A large turbine can have rotors longer than a football field and can produce enough electricity to power 1,400 homes. Utility-scale offshore turbines range in size from 450 kW to 3.6 MW. Gear box connects the low-speed shaft to the high-speed shaft and increases the rotational speeds from about 15 to 30 rotations per minute (rpm) to about 1000 to 1800 rpm, the rotational speed required by most generators (alternators) to produce electricity. Vertical-axis wind turbines (VAWT) have the main rotor shaft arranged vertically. Key advantages of this arrangement are that the turbine does not need to be pointed into the wind to be effective. This is an advantage on sites where the wind direction is highly variable, for example when integrated into buildings. Source


Davis S.,PET
Power Electronics Technology | Year: 2011

One of the widely used battery-based electronic systems is the hearing aid, which needs to exhibit high energy efficiency to achieve maximum battery lifetime while providing high performance features, such as programmability. High energy efficiency is a critical design criterion for the electronic hearing aid placed in or around the ear to improve the hearing of those with hearing loss. The hearing aid needs to provide the appropriate amount of sound reproduction and information processing using battery power, with little power consumption. The Series S is a digital hearing aid that can be programmed during the fitting process with multiple patient-selectable listening profiles. The digitization of sound allows more advanced signal processing, such as noise reduction, filtering, and acoustic feedback control. Source


Roger A.,PET
Power Electronics Technology | Year: 2011

Power management ICs become a key element in many portable and vehicle power circuits. Powering such batteries is calling for newer design strategies in the power management circuits that monitor, charge, and maintain battery performance. These circuits are becoming more highly integrated, more efficient and smaller. Many portable consumer electronics products provide fuel gauges that allow users to know when the batteries need charging and how much life is left in that charge. Balancing a rechargeable battery pack's cells is a critical requirement for longer battery life and greater levels of safety. Linear Technology uses passive cell balancing with its LT6802-1 cell-monitoring IC. It is simpler than the active balancing method. The technique works by shunting a resistor across each cell, in a multi-cell series stack, to dissipate imbalance currents, when the stack is fully charged. Source


Sam D.,PET
Power Electronics Technology | Year: 2011

Development in MOSFET on-resistance is reaching new levels with Picor's PI5101 that achieves sub-milliohm values. The RDS(on)FET device combines a high-performance 5V 360ωlateral N-Channel MOSFET with a thermally enhanced high density 4.1mm, 8mm, and 2mm land-grid-array (LGA) package to enable performance in the footprint area of an industry standard SO-8 package. These features enable the device to be suitable for low voltage, high-current power path management applications. The package is fully compatible with industry-standard SMT assembly processes and most off-the-shelf MOSFET controller ICs. The PI5101 is a companion product for Picor's Power Management IC controllers. It enables on-state low power dissipation for applications such as active ORing, hot swap power managers, load switches, and high current DC-DC converters when combined with a compatible Picor controller. Source


Sam D.,PET
Power Electronics Technology | Year: 2011

Automobile industry experts state that the success of electric vehicles (EV) in the future will depend on its energy source. These vehicles are intended to give power over sustained periods so they must have a high ampere-hour capacity. The price of electricity to run an EV is low as compared with the cost of liquid fuel needed to produce an equivalent amount of energy. Industry estimates note that the cost of buying and recharging a battery is lower than the cost of fossil fuels suitable for propelling a vehicle over its entire service life. Lithium-ion (Li-ion) types offer several advantages over other types of secondary batteries, including lighter weight and higher energy density among all the available battery technologies for EVs. Argonne National Laboratory is addressing the development of individual batteries through a closely integrated R&D effort that addresses the barriers to industry acceptance in an effort to meet future power needs of such vehicles. Source

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