Differentiate constant frequency control technique, PWM and variable frequency control technique principle

Define chopper. Differentiate constant frequency control technique, PWM and variable frequency control technique principle.

Sr No.	Parameter	PWM control (Constant f control)	Variable frequency control	Current limit control
1.	Variable parameter	TON is variable, (f or T is constant) to vary average output voltage.	TON is constant, f is varied to vary average output voltage.	Both TON and T i.e f are variable their values depend on the upper and lower current levels and current ripple.
2.	Design of output filter for continuous current operation	East due to constant frequency operation.	Difficult due to variable frequency operation.	Difficult due to variable frequency operation.
3.	Filter cost	Lowest	Highest	Filter is normally not required.
4.	Application	DC motor speed control	Not used much	DC motor control and SMPS
5.	Output voltage waveforms	Refer figure (a)	Refer figure (b)	Refer figure (c)

figure (a)

figure (b)

figure (c)

1. Pulse Width Modulation (PWM) techniques for chopper

2. Constant Pulse Width Variable Frequency of Chopper (Frequency Modulation)

3. Current Limit Control of Chopper (CLC)