A variable frequency drive (VFD) controls the speed and torque of AC motors by varying the motor input frequency and voltage. It provides benefits like energy savings, better process control, adjustable speed, power factor correction, and overload protection. A VFD converts AC power to DC, stores it in capacitors, and uses pulse width modulation to invert the DC back to a variable frequency AC output to the motor. VFDs feature line reactors to reduce harmonics and are used widely in applications like fans, pumps, textile machinery and water supply to provide significant energy savings over fixed speed drives.

1. Title-
Variable Frequency Drive(VFD)
Presented By- Borse Rishikesh Sanjay

2. Introduction to Variable Frequency
Drive
A variable-frequency drive (VFD) (also
termed adjustable-frequency drive,
variable speed drive, AC drive, micro drive
or inverter drive) is a type of adjustable-
speed drive used in electro-mechanical
drive systems to control AC motor speed
and torque by varying motor input
frequency and voltage.

3. The Purpose Of VFD
1. Energy savings on most pump and fan applications.
2. Better process control and regulation.
3. Speeding up or slowing down a machine or
process.
4. Inherent power-factor correction
5. Emergency bypass capability
6. Protection from overload currents
7. Safe Acceleration

4. Block Diagram

5. VFD Description
 First, the Converter (usually a diode rectifier) converts three-phase AC power
to DC power.
 Next, the DC Bus stores and filters the DC power in a large bank of
capacitors.
 Last, the Inverter (usually a set of six IGBTs) switches or inverts the DC power
in a Pulse Width Modulated (PWM) AC waveform to the motor.

6. Internals Of VFD

7. Line Reactors
• Installed ahead of the drive
• Protect the drive from sudden disturbances
• Reduces the harmonics content introduced by VFD

8. High peaks
without reactor
Reduction Up
to 35% after
reactor

9. VFD Features:
 High-performance optimized voltage space vector V/F algorithm and high efficiency VFD,
low noise and low electromagnetic interference.
 Motor speed monitor function allows smooth start for various loads such as centrifuges
and dewatering machines anytime.
 Built-in software special for constant pressure water supply system enables one VFD to
control two pumps simultaneously without adding extra expansion unit.
 English LED control panel with friendly human-computer interface.
 Real time clock timing control (easily set the variable frequency drive running time)

10. VFD applications
 Widely used in
1. textile
2. Cable
3. Printing& dying
4. Washing
5. Fans & pumps
6. Package
7. Plastic extruding machines,
8. Machinery
9. Constant pressure water supply
10. Constant temperature control

11. Manufactures of VFD
 Siemens
 ABB
 Danfoss
 Larsen and Turbo
 Mitsubishi
 Electrotech

12. • Significant Energy Savings can be
obtained by using VFD
• It requires less Space
• It has a Better design
• It has an Competitive edge
• Retrofits
Conclusion