Power electronics...

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Power electronics is the application of solid-state electronics to the control and conversion of electric power.

The first high power electronic devices were mercury-arc valves. In modern systems the conversion is performed with semiconductorswitching devices such as diodes, thyristorsand transistors, pioneered by R. D. Middlebrook and others beginning in the 1950s. 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 a 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.
The power conversion systems can be classified according to the type of the input and output power
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Power electronics started with the development of the mercury arc rectifier. Invented by Peter Cooper Hewitt in 1902, it was used to convert alternating current (AC) into direct current (DC). From the 1920s on, research continued on applying thyratronsand grid-controlled mercury arc valves to power transmission. Uno Lamm developed a mercury valve with grading electrodes making them suitable for high voltage direct currentpower transmission. In 1933 selenium rectifiers were invented.
In 1947 the bipolar point-contact transistor was invented by Walter H. Brattain and John Bardeen under the direction of William Shockley at Bell Labs. In 1948 Shockley's invention of the bipolar junction transistor(BJT) improved the stability and performance of transistors, and reduced costs. By the 1950s, higher power semiconductor diodesbecame available and started replacing vacuum tubes. In 1956 the silicon controlled rectifier (SCR) was introduced by General Electric, greatly increasing the range of power electronics applications.

By the 1960s the improved switching speed of bipolar junction transistors had allowed for high frequency DC/DC converters. In 1976 power MOSFETs became commercially available. In 1982 the Insulated Gate Bipolar Transistor (IGBT)
The static power converters perform these function of power conversion.
  • The Power Electronic Converter can be classified into.
  • Diode Rectifier.
  • AC to DC Converter (Controlled Rectifier)
  • DC to DC Converter (DC Chopper)
  • AC to AC Converter (AC voltage regulator)
  • DC to AC Converter (Inverter)
  • Static switch
Power Electronics is the study of switching electronic circuits in order to control the flow of electrical energy. Power Electronics is the technology behind switching power supplies, power converters, power inverters, motor drives, and motor soft starters. ... This is why power electronics is being studied over 40 years.



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