chopper transformer

1. 1
INTRODUCTION
A chopper is a static device that converts fixed dc input
voltage to a variable dc output voltage directly

2. prefrence of chopper
transformer
To increase the power available from the
present transformer without reducing its life.
B)To enable a load of different impedance to be
supplied by the same rectifier transformer
within total kilowatt limitations.
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3. Types of chopper
There are two types of choppers
AC
DC
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4. AC link chopper
In AC link chopper,first DC is converted toAC
with the help of an inverter.
After that AC is stepped- up or stepped –down.
Then converted bak to DC by a diode rectifier.
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5. Disadvantages
Expensive
Bulky
Less efficent
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6. 6

7. DC Chopper
A DC chopper is a static device that converts
fixed dc input voltage to a variable dc output
voltage.
This kind of choppers are more efficient as they
involve one stage conversion
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8. Principle of Chopper Operation
A chopper can be said as a high speed on/off
semiconductor switch.
It connects source to load and disconnects the
load from source at high-speed.
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9. 9

10. (a) Based on the output voltage
of the output
the choppers are classified as
 Step-Down Chopper
In this case the average output voltage is less than
the input voltage. It is also known as step down
converter.
 Step-Up Chopper
Here the average output voltage is more than the
input voltage. It is also known as step up converter.
 Step-Up/Down Chopper
This type of converter produces an output voltage
that is either lower or higher than the input voltage
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11. (c) Depending upon the power
loss
the choppers are classified into two categories
 Hard switched Converter
Here the power loss is high during the switching
(ON to OFF and OFF to ON) as a result of the non
zero voltage and current on the power switches.
 Soft switched or resonant converters
In this type of choppers, the power loss is low at the
time of switching as a result of zero voltage and/or
zero current on the switches.
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12. Applications of Choppers
They are used for DC motor control (battery-
supplied vehicles), solar energy conversion and
wind energy conversion.
Used in electric cars, airplanes and spaceships,
where onboard-regulated DC power supplies
are required.
As power supplies in computers, commercial
electronics, electronic instruments.
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13. Refrences
http://www.circuitstoday.com/choppers-an-
introduction
http://www.completepowerelectronics.com/c
onverters/chopper
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