Rockwell Automation 2364F Regenerative DC Bus Supply Unit (RGU) - Manual (Page 29)

Publication 2364F-5.01– October 2003
Overview 1-13
How does the RGU allow power to flow during motoring while
controlling the power factor?
Let’s examine the voltage vector diagram in Figure 1.11.
Symbols in the figures are defined as follows:
• V
line
is the AC line voltage at a 0° degree phase angle
• V
RGU
is the AC terminal voltage of the RGU
• XL is the line impedance
• I
q
is the active current in the AC line (which is shown in phase
with V
line
in Figure 1.10)
• I
d
is the reactive current in the AC line (which is shown lagging I
q
by 90° in Figure 1.10)
• I
line
is the vector sum of I
q
(active current) and I
d
(reactive
current). These currents are controlled by the RGU. (Shown in
Figure 1.10)
Figure 1.10
Motoring Current Vector Diagram, Lagging pf
Note: Iq determines the direction of the current flow. Id
determines the leading or lagging in the power factor.
I
d
V
line
I
q
I
line
To Neutral