Rockwell Automation 2364F Regenerative DC Bus Supply Unit (RGU) - Manual (Page 28)

Publication 2364F-5.01– October 2003
1-12 Overview
How Does the RGU Control Power
Factor in Motoring and
Regenerating Modes of Operation? To understand how the RGU operates in motoring and regeneration
modes, please refer to the example system shown in Figure 1.8, and
the single-phase equivalent diagram of the RGU shown in Figure 1.9.
Figure 1.8
RGU Connected to AC Drives
Figure 1.9
Single-Phase Equivalent Circuit of RGU
To understand what happens to the power factor during RGU
operation, we will examine the following:
• How does the RGU allow power to flow during motoring while
controlling the power factor?
• How does the RGU allow power to flow from the DC bus to the
AC line (regenerating mode of operation) and control the power
factor?
In the upcoming pages, you will find that the magnitude and
phase angle of currents I
d
(reactive) and I
q
(active) will:
• control V
RGU
and V DC Bus
• determine whether the RGU is motoring or regenerating
• determine whether the power factor is leading, lagging, or unity
RGU M
DC
AC
DC
AC
V AC
Reactors +
-
DC Bus
V DC
Caps
M
AC Drives AC Motors
V
line
V
RGU
XL
I
line
+
-
V DC Bus