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DC-DC converter (chopper)

What is Chopper?
A chopper is a static device that converts fixed dc input voltage to a variable dc output voltage directly.  A chopper is a high-speed on/off semiconductor switch. It connects source to load and disconnects the load from source at high-speed.  Also known as dc-to-dc converter.  Widely used for motor control.  Also used in regenerative braking.
Types of Chopper:
• Step-up choppers.
In step up chopper output voltage is more than input voltage.
• Step-down choppers.
In step down chopper output voltage is less than input voltage.

Basic Block Diagram of Chopper:

Figure below shows the basic block diagram of chopper.
chopper1

Basic principal behind the chopper is it converts Fix DC input voltage to Variable DC output voltage.

Low power application: GTO, IGBT, Power BJT, Power MOSFET etc.
High power application: Thyristor or SCR.

Applications of Chopper:
• They are used for DC motor control (battery-supplied vehicles), solar energy conversion and wind energy conversion.
• Choppers are used in electric cars, airplanes and spaceships, where onboard-regulated DC power supplies are required.
• In general, Chopper circuits are used as power supplies in computers, commercial electronics, and electronic instruments.
• DC Motor Speed Control
• Battery Chargers
• DC Voltage Boosting
• Battery Operated Electric Cars