Introduction To power Electronics – lecture1

Introduction:

Power Electronics is defined as control and conversion of large amounts of electrical power .

Why control and conversion is required

A power electronics system consists of an electrical source , load , and a power electronic circuit .

PE circuit containing switches , energy storage elements and control functions .

Power electronic applications deal with the flow of power .

However , majority of applications in PEs are based on switching the power flow in order to improve efficiency .

consequently , one must use power semiconductor devices with an emphasis on using them as PE switches .

Few of the common power semiconductor switches are diodes , BJTs , MOSFETs , IFBTs.

Power MOSFETs and IGBTs have a large role to play in modern power control equipment’s and hence their study is emphasised.

Power electronics is a vast , complex and interdisciplinary subject that has undergone through a rapid technological evolution during the last 50 years .

Due to advancement in technology with decreased apparatus cost and improved reliability , the application of PE are expanding in industrial , commercial , aerospace , residential , military , and utility environments .

Many innovations in the field of power semiconductor devices , converter topologies , electric machine drives , control etc

The frontier of this technology has been further advanced by the versatile use of AI techniques , such as fuzzy logic and the artificial neural network .

In 1957 , the silicon-controlled rectifier (SCR) was introduced , and later other power semiconductor devices have been developed with the advancement in the semiconductor technology .

Power diodes are available up to the ratings of 3000V , 3500A and 1KHz , whereas thyristors are available up to 6000V , 3500A , 1KHz

BJTs are available in the market up to the ratings of 1200V , 400A and 10KHz .

Power MOSFETs have relatively low ranges of approximately 1000V and 50A with high frequency of 100KHz.

IGBTs are available up to ower ratings of 1200V , 400A and 20KHz.

DIODE RECTIFIERS

A diode rectifier circuit converts AC input voltage into a fixed DC voltage.

The input voltage may be single phase or three phase.

Diode rectifiers find wide use in, electric traction battery charging, power supplies, welding, and UPS systems.

Password : PowerElectronicsBala

pdf made by Dr M Balasubbareddy

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