Active Power in 1~AC mainsApparent / Reactive / Active Power

~ L

W0P

~ C

cosIUPW0P

~ R

pure resistor R : phase shift = 0°

active power

1

pure reactance L : phase shift = 90°

no active power

pure capacitance C : phase shift = 90°

no active power

Apparent / Reactive / Active Power

applicable for distorted voltage and current (harmonics)

wave-form must not be continuous

Power Factor

distorted voltage contains harmonics

By means of

Fourier transformation

a distorted wave form can be synthesized by a infinite number of sine-waves of ascending order

Power Factor

Current Power Factor 0,53

distorted AC current caused by rectifier

Power Factor 1~AC mains current without PFC

mains current harmonics / Fourier transformation

current harmonics in mains supply

Inetz [mA]

0

100

200

300

400

500

600

700

50 150 250 350 450 550 650 750 850 950

w/o PFC

Power Factor current harmonics 1~AC fan without PFC

Limits acc. DIN EN61000-3-2

harmonic number permitted maximum valuen A rms

3 2,305 1,147 0,779 0,4011 0,3313 0,21

15<=n<=39 0,15 x 15/n

2 1,084 0,436 0,30

8<=n<=40 0,23 x 8/n

odd harmonics

even harmonics

Limits for class A-devices Power factor (PF)

Power FactorDIN EN61000-3-2

DC-linkcapacitorUac

rectifier

Power Factor Correction PFC1~AC mains input – circuit without PFC

Choke

DC-Link capacitorUac

rectifier

Power Factor Correction PFC 1~AC mains input – circuit with 1~choke (passive PFC)

choke boost-diode

DC-linkcapacitor

shunt

MOS-FET

capacitorUac

rectifier

Power Factor Correction1~AC-mains input – circuit with active PFC

reduced harmonics by PFC

w/o PFCPower Factor = 0,53

current IRMS = 958 mA

with active PFCPower Factor = 0,99

current IRMS = 628 mA

Power Factor Correction

Current harmonics with and without aktive PFC compared in the same duty point

@ 230V50Hz

Imains [mA]

0

100

200

300

400

500

600

700

1 3 5 7 9 11 13 15 17 19

without PFC

with PFC

Power Factor1~AC with active PFC / without

distorted AC current caused by rectifier

cables, switches and fuses are dimensioned according to current !

EC-fan connected to 1~AC mains

EC-M

L

N

277 V / 60 Hz

IRMS w/o PFC passive PFC aktive PFC 150% 144% 100%

EC fan without PFC shows plus 50% more current draw !

Harmonic No w/o PFC passive PFC active PFC

1 100% 100% 100%

3 86% 82% 5%

5 61% 54% 4%

7 35% 28% 1%

9 13% 11% 3%

11 4% 4% 1%

13 8% 1% 1%

15 7% 2% 1%

17 3% 3% 0%

19 1% 2% 1%

Harmonic Current

typical values ! referenced to 1st harmonic !

cables, switches and fuses are dimensioned according to current !

EC-fan connected to 1~AC mains

w/o PFC

IRMS =150%

passive PFC

IRMS =144%

active PFC

IRMS =100%

„passive“ PFC is not really effective for 1~AC mains!

Many 1~AC fans connected to 3~AC mains supply

EC-M

L3

N

EC-M

L2

EC-M

L1

cables, switches and fuses are dimensioned according to current !

w/o PFC passive PFC active PFC

IRMS 150% 144% 100%

INeutral 318% 285% 27%

EC fans without PFC show 12-times as much current draw in Neutral !

Many 1~AC fans connected to 3~AC mains supply

cables, switches and fuses are dimensioned according to current !

IRMS 150%

w/o PFC

INeutral 318%

IRMS 144%

passive PFC

INeutral 285%

IRMS 100%

active PFC

INeutral 27%

w/o PFC passive PFC active PFC

IRMS 150% 144% 100%

INeutral 318% 285% 27%

EC fan w/o PFC shows

1,5- times as much phase current and 12- times as much current in Neutral compared to active PFC!

Many 1~AC fans connected to 3~AC mains supply Current in Phase and Neutral wire

No PFC Passive PFC Active PFC

150% 144% 100%

112% 103% 7.4%

THFactor 0.75 0.72 0.073

PF 0.67 0.70 0.997

RMS-current, THD, THF, & Power Factor

40

1

2

nnIIRMSRel =

1

40

2

2

I

In

nTHDi =

ebm-papst Power Factor Controllereffective current with / without PFC

Current harmonics

Inetz [mA]

0

100

200

300

400

500

600

700

800

900

1000

1 3 5 7 9 11 13 15 17 RMS

w /o PFC

w PFC

Power Factor with / without passive PFC / 1~AC mains

mains current w/o PFC is 50% higher as with active PFC

w/o PFCIRMS = 0,96A

with PFCIRMS = 0,64A

Power Factorwith / without passive PFC / 1~AC mains

Inetz [mA]

Power Factorwith / without passive PFC / 3~AC mains

frequency inverter, mains (3~AC)100% set-rate without PFC Power Factor 0,54 P1 : 2,2 kW PS : 4,0 kVA IN : 6,0 A

EC-SYSTEMS, mains (3~AC)100% set-rate with passive PFC Power Factor 0,93 P1 : 1,75 kW PS : 1,85 kVA IN : 2,8 A

definition / formula

Effektive Current

40

1

2

nnIIRMS =

definition / formula

THD Total Harmonic Distortioncurrent

1

40

2

2

I

In

nTHDi =

definition / formula

THF Total Harmonic Factorcurrent

RMS

nn

I

I

40

2

2

THFi =

40

1

2

40

2

2

nn

nn

I

I

=

PF = effective power / apparent power

Power FactorDefinition / formula

=RMSI

I1

40

1

2

1

nnI

I=PF =

low Power Factor meanshigh currenthigh installation cost

Effective current and Power Factor

=PF

I1RMSI