Derivation of Average Output Voltage
From the waveforms , we can see that the load voltage flows only during the turn ON period(Ton) of the chopper .The average output voltage is given by ,
When switch is closed, diode is reverse biased and supply voltage will charge the inductor.
Vdc = Average value of output or load voltage.
I dc = Average value of output or load current.
ton =Time interval for which SCR conducts.
toff =Time interval for which SCR is OFF.
T =ton + toff = Period of switching or chopping period.
f = (1/T) = Frequency of chopper switching or chopping frequency.
Average output voltage
VL(avg) = (1/T) T∫0 VL dt
= (1/T) [ Ton∫0 Vdc dt + Toff∫0 0 dt]
= (Vdc /T) Ton∫0 1. dt
= (Vdc / T) . Ton
VL (avg) = Vdc .δ
Average output current
I dc = Vdc/R
I dc= (V/R)(ton/T)
I dc = (V/R). δ
Step Down Chopper
In power electronics, a chopper refers to a type of electronic switch that is used to control the flow of electrical power. It functions as a high-speed ON/OFF semiconductor switch that modulates the voltage or current in a circuit. A chopper is a static device that transforms a fixed DC input voltage into a variable DC output voltage. It acts as the DC counterpart(equivalent) of an AC transformer due to its similar behavior. These are also used in trolley cars, marine hoists, forklift trucks, and mine haulers. Future electric automobiles are likely to use choppers for their speed control and braking. The chopper system offers smooth control, high efficiency, fast response, and regeneration.
Table of Content
- What is Chopper?
- Classification of Chopper
- Construction and Components of Step-Down Chopper
- Step-Down Chopper with Low Pass Filter
- Advantages of Step Down Chopper
- Disadvantages of Step Down Chopper
- Applications of Step Down Chopper
Contact Us