what is a variable frequency drive? how does it save · pdf filewhat is a variable frequency...

What is a Variable Frequency Drive?

How does it save energy?

Jason Fahey

EnSync Inc

10-12-2016

How does a VFD Work How does a VFD Work

Fixed Voltage

Fixed Frequency

Line

Voltage

AC/DC

DC Bus

DC/PWM

Motor

Drive Block Diagram

AC AC (PWM) DC

CONVERTER INVERTER

Variable Voltage

Variable Frequency

B+

B-

The VFD first CONVERTS AC to DC This is done in the “Converter Section”

B+

B-

DC is then INVERTED to Pulse Width Modulation (PWM) This is done in the “Inverter Section”

B+

B-

Today's VFDs are PWM style drives

RECTIFIER

Positive

DC Bus

Negative

DC Bus

+

-

INVERTER

+650VDC

RECTIFIER

Positive

DC Bus

Negative

DC Bus

+

-

INVERTER

0VDC

RECTIFIER

Positive

DC Bus

Negative

DC Bus

+

-

INVERTER

-650VDC

RECTIFIER

Positive

DC Bus

Negative

DC Bus

+

-

INVERTER

0VDC

RECTIFIER

Positive

DC Bus

Negative

DC Bus

+

-

INVERTER

RECTIFIER

Positive

DC Bus

Negative

DC Bus

+

-

INVERTER

RECTIFIER

Positive

DC Bus

Negative

DC Bus

+

-

INVERTER

RECTIFIER

Positive

DC Bus

Negative

DC Bus

+

-

INVERTER

Area Under The Square-Wave Pulses

Approximates The Area Under A Sine Wave

Frequency

Vo

lta

ge

“Electric motors and the systems they drive are the single largest electrical

end‐use, consuming more than twice as much as lighting, the next largest

end‐use. It is estimated that EDMS account for between 43% and 46% of all

global electricity consumption…” Paul WaIde and Conrad U. Brunner, International Energy Agency, 2011

A centrifugal fan is a mechanical device

for moving air or gases. It has a fan

wheel composed of a number of fan

blades mounted around a hub.

A centrifugal pump is a rotodynamic

pump that uses a rotating impeller to

increase the pressure of a fluid.

100% Supplied 70% Needed

70% Supplied 70% Needed

100% Supplied 70% Needed

70% Supplied

70% Needed

Q N flow rate proportional to

rotary speed

H N2 head (pressure) proportional to

rotary speed squared

P N3 power proportional to

rotary speed cubed

Large decrease in power

requirement for relatively

small decrease in flow

The opportunity is significant

“In the United States, an estimated 60-65% of

electrical energy is used to supply motors,

75% of which are variable-torque fan, pump

and compressor loads.” ~Wikipedia

Ameren Illinois Energy Efficiency Program Incentives:

24

• Variable Frequency Drives

• Pumps and Fans up to 500hp

• $115/hp controlled

• Visit Actonenergy.com/vfd-incentives

Ameren Illinois Energy Efficiency

Program Energy Advisors

Call 1.866.800.0747

to request a consultation with an

Energy Advisor

1. Chad Whitehead Chad.Whitehead@gdsassociates.com 309.620.6333 2. Steven Smith Steven.L.Smith@leidos.com 309.212.5831 3. Rod Rhoads Rod.Rhoads@gdsassociates.com 217.649.8897 4. Mark Steinmetz Mark.Steinmetz@gdsassociates.com 217.670.9606 5. John Strode John.Strode@gdsassociates.com 309.370.0062 6. Fred Joshu Fred.M.Joshu@leidos.com 309.433.4316 7. Larry Erwin Lawrence.F.Erwin@leidos.com 309.838.2340

Questions?

26

Jason Fahey

Vice President

En-Sync Group, Inc.

jasonf@ensync1.com

www.ensyncinc.com