Parallel Use To Increase Output Power; Parallel Use For Redundancy - Puls DIMENSION CD Series Manual

CD-Series
22.8. P U
ARALLEL
The DC/DC-converter can be paralleled to increase the output power. There are
no feature included which balances the load current between the DC/DC-
converters. Therefore some restrictions and limitations apply. The DC/DC-
converter with the higher adjusted output voltage draws current until it goes
into current limitation. This means no harm or switch-off to this DC/DC-converter
as long as the ambient temperature stays below 45°C.
The output voltages of all DC/DC-converters shall be adjusted to the same value
(±100mV) at full load. A fuse or diode on the output of each unit is only required
if more than three units are connected in parallel. This avoid that more than 2
times of the nominal output current can flow backwards into the DC/DC
converter in case the output stage of the DC/DC converter has a defect. If a fuse (or circuit breaker) is used, choose on
with approximately 150% of the rated ou
Keep an installation clearance of 15mm (left / right) between two DC/DC-converters and avoid installing the DC/DC-
converters on top of each other. Do not use DC/DC-converters in parallel in mounting orientations other than the
standard mounting orientation (input terminals on the bottom and output terminals on top of the unit).
22.9. P U
ARALLEL
The DC/DC converters can be paralleled for 1+1 redundancy
to gain higher system availability. Redundant systems require
a certain amount of extra power to support the load in case
one DC/DC converter fails. The simplest way is to connect two
DC/DC converters in parallel. This is called a 1+1 redundancy.
In case one DC/DC converter fails, the other one is
automatically able to support the load current without any
interruption. Redundant systems for a higher power demand
are usually built in an N+1 method. E.g. five DC/DC
converters, each rated for 10A are paralleled to build a 40A
redundant system.
Furthermore, 1+1 redundant systems can be built by using a
DC/DC converter powered from a battery and a power supply
with AC input.
Please note: This simple way to build a redundant system
does not cover failures such as an internal short circuit in the secondary side of the DC/DC-converter. In such a case, the
defect unit becomes a load for the other DC/DC-converters and the output voltage can not be maintained any more.
This can only be avoided by utilizing the redundancy module YR20.246, which utilized MOSFETs as decoupling devices.
Recommendations for building redundant power systems:
a) Use separate input fuses for each DC/DC-converter.
b) Monitor the "Redundancy OK" relay contact of the YR20.246. This feature reports a faulty DC/DC converter or
problems with the redundancy modules.
c) 1+1 Redundancy is allowed up to an ambient temperature of 60°C
N+1 Redundancy is allowed up to an ambient temperature of 45°C
d) It is desirable to set the output voltages of all units to the same value (± 100mV) or leave it at the factory setting.
Use the load share feature LEDs of the redundancy module to adjust the output voltages of the DC/DC coverters if
necessary.
Jul. 2017 / Rev. 1.1 DS-CD10.241-EN
after a 5 minutes run-in time unless otherwise noted.
I O
SE TO NCREASE UTPUT
tput current of one DC/DC-converter.
R
SE FOR EDUNDANCY
All parameters are typical values at 24V, 10A, 24Vdc input voltage, 25°C ambient and
www.pulspower.com Phone +49 89 9278 0
DC/DC Converter 24V/24V, 10A, 240W
P
OWER
- -
+ + + +
Output Output
24-28V 24-28V
DC-OK DC-OK
CD10.241 CD10.241
DC/DC DC/DC
Converter Converter
Input
+ - +
I I
+
-
Functional Earth
Germany
CD10.241
Unit A
+
Input
-
Output
Unit B
+
Input
-
Output
- -
- -
+ +
In1 In2
YR20.246
Redundancy Module
Load Share
OK
Redundancy
OK
Output
Input
-
+
-
24V,10A
Load
+
-
e
Failure
Monitor
Load
23/25