Danfoss VLT HVAC Basic Drive FC 101 - Power Factor

VVC
plus
Compared with standard voltage/frequency ratio control,
Voltage Vector Control (VVC
plus
) improves the dynamics
and stability, both when the speed reference is changed
and in relation to the load torque.
1.7 Power Factor
The power factor is the relation between I
1
and I
RMS
.
Power factor =
3 × U × I
1 × COS ϕ
3 × U × I
RMS
The power factor for 3-phase control:
=
I
1
× cos ϕ1
I
RMS
=
I
1
I
RMS
since cos ϕ1 = 1
The power factor indicates to which extent the adjustable
frequency drive imposes a load on the line power supply.
The lower the power factor, the higher the I
RMS
for the
same kW performance.
I
RMS
= I
1
2
+ I
5
2
+ I
7
2
+ . . + I
n
2
In addition, a high power factor indicates that the different
harmonic currents are low.
The adjustable frequency drive's built-in DC coils produce a
high power factor, which minimizes the imposed load on
the line power supply.
Introduction Design Guide
8 Danfoss A/S © Rev. 2014-01-14 All rights reserved. MG18C522
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