04-06-2013, 01:06 PM
Seminar Topic on CHOPER
CHOPER.ppt (Size: 1.27 MB / Downloads: 29)
Introduction
DC-DC converter (chopper) is used to convert constant DC voltage into variable DC voltage.
In DC-DC conversion circuits, thyristors are used as switching elements. Here thyristors must be turned off using forced commutation as they lack facility of natural commutation that is available in AC circuits.
Buck chopper produces output that is less than or equal to input voltage.
Boost chopper provides an output voltage that is greater than or equal to input voltage.
Typical application of DC choppers is DC motor speed control.
Principles Of Basic DC Choppers
Switch is turned on and off periodically. In this way constant voltage can be connected to and disconnected from the load.
By a periodic application of constant voltage at a particular frequency across the load, variable voltage can be achieved by controlling the on period of the switch.