Rockwell Automation 2364P Parallel DC Bus Supply Config. - Manual (Page 16)

Publication 2364P-5.01 December 1999
1-4 Theory of Operation
Output of RGU//RGU Configurations
In an RGU//RGU configuration, each RGU (when enabled) switches
its IGBTs to maintain a constant voltage on the DC bus (which is
typically 1.52 times the input voltage).
In this process, the master RGU evaluates the bus voltage and sends a
current command (which is used to correct the bus voltage) to the
slave RGUs. Each RGU switches its IGBTs to regulate the current
(motoring or regenerative) needed to maintain the bus voltage.
Figure 1.5
RGU//RGU Bus Voltage–Motoring or Regenerating
When the RGUs are not enabled, power is supplied through the free-
wheeling diodes. The diode bridge produces a voltage of 1.35 times
the input voltage with no load, and decreases to 1.22 times the input
voltage at full load. During this operation, the RGUs do not regulate
the voltage or regenerate any current.
Figure 1.6
RGU//RGU Bus Voltage–Diode Bridge Operation (RGU Not Enabled)
% Load
DC
B
u
s V
o
lt
ag
e
10 0% 0 %
0 V D C
~ 1.5 2 x V A C
% Load
DC
B
u
s V
o
lt
ag
e
10 0% 0 %
0 V D C
1.3 5 x V A C
1.2 2 x V A C