Power Electronics

Power electronics is used to change the voltage and current magnitude and/or frequency characteristics of electrical power to suit a particular application. Unlike normal electronics which use current and voltage to carry information, power electronics carry power. This is why the main task of power electronics is to control and convert electrical power from one form to another. The four main forms of conversion are AC to DC (Rectifier), DC to AC (Inverter), AC to AC (Cycloconverter and Cycloinverter) and DC to DC (Chopper or switch-mode power supply) conversions. This is accomplished through the extensive use of inductors, capacitors and diodes which can be operated at high frequencies [1].

Since the power that comes from transmission and distribution lines is at a set frequency of 60 Hz in the U.S. and 50 Hz in most other parts of the world, it must be conditioned in order to fit many applications. For example, incandescent bulbs used in a movie theater are supplied with an ac voltage controller that allows the gradual dimming of the lights. It is currently estimated that at least half of the electric power generated in the U.S. flows through power electronic converters with an expected increase to 100% over the next few decades [2].

Power Electronics Specific Topics:

Notable People

  • Julius Edgar Linienfeld was born on April 18, 1882 in Lemberg Austria-Hungary. On October 22, 1925 he filed a patent in Canada describing a device similar to a MESFET. The patent was then accepted in the US gaining the patent number US 1745175 entitled “Method and apparatus for controlling electric current.” In March 28, 1928 he filed for another patent in the US. It was accepted and given a patent number US 1900018 entitled “Device for controlling electric current.” Linienfeld continued to apply for patents in the same field of study for the next 10 years. In that time Lilienfeld became an American citizen in 1934. In August 28, 1963 Julius Edgar Lilienfeld passed away leaving the path for many more advancements in the Power Electronics field [3].
  • Walter Houser Brattain (February 10, 1902 – October 13, 1987) was an American physicist at Bell Labs who, along with John Bardeen and William Shockley, invented the transistor. They shared the 1956 Nobel Prize in Physics for their invention. He devoted much of his life to research on surface states. On December 16, 1947 Brattain and John Bardeen first demonstrated a point contact transistor for the first time.
  • Along with inventing the transistor John Bardeen (May 23, 1908 – January 30, 1991) an American physicist and electrical engineer won the Nobel prize a second time due to his work with Leon Neil Cooper and John Robert Schrieffer for a fundamental theory of conventional superconductivity known as the BCS theory in 1972. With these advancements America entered into the informational era [4].
  • William Bradford Shockley Jr. (February 13, 1910 – August 12, 1989) was an American physicist and inventor. After his work with Walther Brattain and John Bardeen, Shockley moved to California and worded on commercializing the new transistor design in the 1950’s and 1960’s which lead to the California “Silicon Valley’s” becoming a national hotspot for innovations in electronics [5].
  • Gordon Kidd Teal (January 10, 1907 – January 7, 2003) invented a method to improve transistors by applying the Czochralski method to produce extremely puregermanium single crystals. Together with Morgan Sparks they invented a process to produce a Bipolar Junction Transistor (BJT) by modifying the fabrication process of the transistor. This made it more possible to use the transistors in everyday life [6].

References:

  1. http://services.eng.uts.edu.au/~venkat/pe_html/ch01/ch01_p1.htm Retrieved March 2012.
  2. Andrezej M. Trzynadolwski (January 2010). “Introduction to Modern Power Electronics” http://books.google.com/books?id=o0IgIidEk8AC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false. Retrieved March 2012.
  3. Mary Bellis. "Dr. Julius Edgar Lilienfeld", about.com Inventors. N.p., n.d. . Retrieved March 20th, 2012.
  4. "Walter H. Brattain - Biography". http://www.nobelprize.org/nobel_prizes/physics/laureates/1956/brattain-bio.html. Retrieved March 21st, 2012.
  5. "John Bardeen - Biography". http://www.nobelprize.org/nobel_prizes/physics/laureates/1956/bardeen.html. Retrieved March 21st, 2012.
  6. "William B. Shockley - Biography". http://www.nobelprize.org/nobel_prizes/physics/laureates/1956/shockley-bio.html. Retrieved March 21st, 2012.

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