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Power electronics is the technology associated with the efficient conversion, control and conditioning of electric power by static means from its available input form into the desired electrical output form. By the mid 20th century humans had achieved a mastery of technology sufficient to leave the surface of the Earth for the first time and explore space. ...
Introduction
Power electronic converters can be found wherever there is a need to modify the electrical energy form (i.e modify its voltage, current or frequency). Therefore, their power range from some milliwatts (as in a mobile phone) to hundreds of megawatts (e.g in a HVDC transmission system). With "classical" electronics, electrical currents and voltage are used to carry information, whereas with power electronics, they carry power. Therefore the main metric of power electronics becomes the efficiency. HVDC or high-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power. ...
The first very high power electronic devices were mercury arc valves. In modern systems the conversion is performed with semiconductor switching devices such as diodes, thyristors and transistors. In contrast to electronic systems concerned with transmission and processing of signals and data, in power electronics substantial amounts of electrical energy are processed. An AC/DC converter (rectifier) is the most typical power electronics device found in many consumer electronic devices, e.g., television sets, personal computers, battery chargers, etc. The power range is typically from tens of watts to several hundred watts. In industry the most common application is the variable speed drive (VSD) that is used to control an induction motor. The power range of VSDs start from a few hundred watts and end at tens of megawatts. A mercury arc valve (mercury vapor rectifier) is a type of electrical rectifier which converts alternating current into direct current. ...
A semiconductor is a solid whose electrical conductivity can be controlled over a wide range, either permanently or dynamically. ...
Types of diodes A diode functions as the electronic version of a one-way valve. ...
The thyristor is a solid-state semiconductor device similar to a diode, with an extra terminal which is used to turn it on. ...
Photo of transistor types (tape measure marked in centimeters) Transistor in the SMD form factor The transistor is a solid state semiconductor device used for amplification and switching. ...
This article is about the band. ...
AC, half-wave and full wave rectified signals A rectifier is an electrical device, comprising one or more semiconductive devices (such as diodes) or vacuum tubes arranged for converting alternating current to direct current. ...
A BlueGene supercomputer cabinet. ...
Battery charger A battery charger is a device used to put energy into a cell or battery by forcing an electric current through that cell or battery. ...
The watt (symbol: W) is the SI derived unit of power, equal to one joule per second. ...
Adjustable speed drive (ASD) is one of the most general terms applied to equipment used to control the speed of machinery. ...
Electric motors of various sizes. ...
The megawatt (symbol: MW) is a unit for measuring power corresponding to one million (106) watts. ...
The power conversion systems can be classified according to the type of the input and output power
City lights viewed in a motion blurred exposure. ...
Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ...
AC, half-wave and full wave rectified signals A rectifier is an electrical device, comprising one or more semiconductive devices (such as diodes) or vacuum tubes arranged for converting alternating current to direct current. ...
Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ...
City lights viewed in a motion blurred exposure. ...
An inverter is an electronic circuit for converting direct current (DC) to alternating current (AC). ...
Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ...
Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ...
In electronics engineering, a DC to DC converter is a circuit which converts a source of Direct Current from one voltage to another. ...
Principle As efficiency is at a premium in a power electronic converter, the losses that a power electronic device generates should be as low as possible. The instantaneous dissipated power of a device is equal to the product of the voltage across the device and the current through it (). From this, one can see that the losses of a power device are at a minimum when the voltage across it is zero (the device is in the On-State) or when no current flows through it (Off-State). Therefore, a power electronic converter is built around one (or more) device operating in switching mode (either On or Off). With such a structure, the energy is transferred from the input of the converter to its output by bursts.
Applications Power electronic systems are virtually in every electronic device. For example, around us: - DC/DC converters are used in most mobile devices (mobile phone, pda...) to maintain the voltage at a fixed value whatever the charge level of the battery is. These converters are also used for electronic isolation and power factor correction.
- AC/DC converters are used every time an electronic device is connected to the mains (computer, television,...)
- AC/AC converters are used to change either the voltage level or the frequency (international power adapters, light dimmer). In power distribution networks AC/AC converters may be used to exchange power between utility frequency 50 Hz and 60 Hz power grids.
The utility frequency is the frequency at which alternating current is transmitted from a power plant to the end user. ...
See also Power semiconductor devices are semiconductor devices used as switches or rectifiers in power electronic circuits (switch mode power supplies for example). ...
References Issa Batarseh, "Power Electronic Circuits" by John Wiley, 2003. |
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