Single, Two and Four Quadrant Choppers
Q. Classify choppers based on output voltage and quadrants of operation. Give applications of chopper. (at least four)
Q. Classify choppers based on output voltage and quadrants of operation. List four applications of chopper.
Q. Classify choppers based on quadrants.
- The dc choppers consist of power switches such as SCR, power transistor, power MOSFETS, IGBTS etc., and diodes connected in suitable circuit configurations.
- The circuit configurations can be simplified to a great extent if the power switches and the diodes are assumed to be ideal.
- The ideal switches and diodes are assumed to have following characteristics :
Characteristics of power devices and diodes
- The power switches have zero resistance when they are closed and infinite resistance when they are open (off).
- The switches can be closed and opened instantaneously, independent of the current through them. That means the time required to turn on or turn off a power switch or diode is zero.
- In the closed state the switches carry current in one direction only. It does not allow reverse conduction all.
- The diodes have zero resistance when forward biased and infinite resistance when reverse biased. The threshold voltage is zero.
Classification of choppers
1. Choppers
i) Single quadrant choppers
Type A chopper
Type B chopper
ii) Two quadrant choppers
Type C chopper
Type D chopper
iii) Four quadrant choppers
Type E chopper
- The operation of the ideal choppers is confined to certain quadrants of the output voltage output current characteristics.
- This is used as the basis for the classification of choppers in single quadrant, two quadrant and four quadrant configurations.