Variable Frequency
Drive
Donald Kaulukukui
What is a VFD?




Variable Frequency Drive (VFD)
A VFD can be used to control both the speed and
torque of a standard induction AC electric motor.
It varies both the frequency and amps of the AC
waveform being delivered to the motor saving
money in electricity.
Basic components of a VFD:

Input section, draws AC electric power from the
utility, Rectifier section, converts the AC into DC
power.

Inverter section, converts DC back into a
controllable AC waveform.
Purpose of the VFD

VFDs help to limit demand and electrical
consumption of motors by reducing the
amount of energy they consume.
 Standard
motors are constant speed and
when they are energized they run at a 100%
no matter the load.
 Soft Start
 Only use energy you need
Ohana Malia - Booster Pump Amps
20.00
New Booster Pumping System
Installed
18.00
14.00
12.00
10.00
8.00
6.00
4.00
Time
5:00 PM
5:00 PM
5:00 PM
5:00 PM
5:00 PM
5:00 PM
0.00
5:00 PM
2.00
5:00 PM
Booster Pump Amps
16.00
Potential Problems
Improper Circuit Design
 Harmonic Distortion
 Safety
 3 phase generation
 Microcontroller programming

Expectations
Learn pulse width modulation techniques
 Learn application of microcontroller
features
 Learn advanced circuit design
 Learn AC motor theory
 Learn energy conservation methods

Goals

Single phase 120V 60 Hz AC generation

Three phase 220V 60 Hz AC generation

Three phase 220V Variable Frequency AC
generation

Temperature controlled VFD
VFD
Start
Done
Circuit Design
Duration
Programming
AC - DC converter
DC - DC converter
DC - AC inverter
8/26/2007
9/15/2007
10/5/2007 10/25/2007 11/14/2007 12/4/2007 12/24/2007 1/13/2008
2/2/2008