A variable frequency drive (VFD) controls the speed and torque of an AC electric motor by varying the frequency and voltage of the power supplied to the motor. It does this by drawing AC power from the utility, converting it to DC, and then converting the DC back to a variable AC waveform. VFDs help conserve energy by only providing the power needed based on the motor's load, rather than running the motor at full speed all the time. The document outlines the basic components and operation of a VFD, as well as goals and timelines for designing and building a VFD circuit.

1. Variable Frequency
Drive
Donald Kaulukukui

2. 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.

3. 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

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6. Potential Problems
 Improper Circuit Design
 Harmonic Distortion
 Safety
 3 phase generation
 Microcontroller programming

7. Expectations
 Learn pulse width modulation techniques
 Learn application of microcontroller
features
 Learn advanced circuit design
 Learn AC motor theory
 Learn energy conservation methods

8. 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

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VFD
Circuit Design
Programming
AC - DC converter
DC - DC converter
DC - AC inverter
Start
Done
Duration

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VFD
Circuit Design
Programming
AC - DC converter
DC - DC converter
DC - AC inverter
Start
Done
Duration