User Manual

Chapter 8 - BSPS
1QDF10134AAP-SYD-FCC Issue 03
Draft 02
8-9 of 8-16
8.5. Basic Rectifier Module
The PFC50-6 rectifier module is the heart of the Full-Redundancy 48VDC power
system. It is a plugged-in module designed specifically for modular systems. The
power factor correction (PFC) device at the input enables clean, stable, sinusoidal
current consumption from the mains. This converter produces a 382VDC output,
which is then converted to the 50V output.
A current sharing circuit is responsible for current sharing among the rectifiers. This
enables each one of the rectifiers to slightly increase its output voltage.
The rectifiers follow the highest output voltage of the rectifiers that are used.
For example:
There are 2 rectifiers in the system, one of the rectifiers has an output voltage that is
greater than that of the other rectifier. The rectifier with the higher output voltage
will become the master and dictate the output voltage of the total system. The
second rectifier raises its voltage slightly until its output current equals the output
current of the master rectifier. Hence, one rectifier in the system is the master and
the other rectifiers are slaves.
When the master rectifier fails to operate, the rectifier with the next highest initial
output automatically becomes the new master of the system.
Note: The sharing mechanism tends to raise the system’s output voltage. A limit of
approximately one-volt of correction is applied to the system.
The output current indication is indicated by the LED bar graph shown on the front
panel (see Figure 8-8). This bar graph is used to verify current sharing operation,
and to indicate the percentage of the full load.
An RFI input filter built into the input stage suppresses the generated noise
travelling to the line.