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
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.
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