POWER SEMICONDUCTOR DEVICES
Power electronics is a combination of two engineering fields power engineering and electronics engineering. In power engineering the equipments and apparatus are rated at high level and high efficiency. In electronics engineering, all the apparatus are rated at signal level without much consideration of efficiency. Power engineering covers the transmission generation distribution and utilization of electrical energy. Transmission and reception of data distortionless production signals of very low power level comes in electronics engineering. Hence the apparatus of power electronics are rated at power level but works on the principle of electronics.
The electronics power conversion circuit use power semiconductor devices and these circuits convert and control electronics power. These devices operate in the switching mode. Which causes the losses to be reduced and therefore the conversion efficiency its to be improved. The disadvantages of switching mode operation are the generation of harmonics. Now a days the technology is advancing and apparatus cost is decreasing along with the improvement of reliability. Therefore the applicant of power electronics devices are expanding in industrial commercial residential military aerospace and utility environments. The progress in power electronics is due to advance in power semiconductor devices.
In 1957 bell laboratories were the first to fabricate a silicon based semiconductor device called thyristor and it was introduced by GEC. This company did a great deal of pioneering work about the utility of thyristors in industrial application. Later on many other semiconductor devices having characteristics identical to that of a thyristor ere developed and these are traic. Dirac power diode power BJT, power MOSEFT SILICON CONTROLED switch programmable injunction transistor ( PUT) IGBT, S?IT ,SITH, GTO, MTC, RCT, etc. This whole family of semiconductor devices used for power control in de and ac systems. Silition controlled rectifier is one oldest member of this thyristor family and is the most widely used device. At present the use of SCR is so vast that over the years the world thyristor has become synonymous with SCR. It appears that the term thyristor is now becoming more common than the actual term SE CR, in this book the term SCR and thyristor will be used at random for the same device SCR.
This chapter deals the terminal V-1 characteristics and switching characteristics of power diode power transistor thyristor diac traic GTO Power MOSEFT. In the last of this chapter two transistor model of thyristor has been discussed.