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EPS Stromversorgung GmbH
Alter Postweg 101 • 86159 Augsburg
Germany
Fon: +49 821 / 570451-0
Fax: +49 821 / 570451-25
PSI 9000 3U Series
3.10.3 Two quadrants operation (2QO)
3.10.3.1 Introduction
This way of operating refers to the use of a source, in this case a power supply
of series PSI 9000 3U, and a sink, in this case a series ELR 9000 electronic
load. The source and the sink function alternatingly in order to test a device,
such as a battery, by deliberately charging and discharging it as part of a func
-
tional or final test.
The user can decide whether the system is operated manually or the power
supply only as the dominant unit or both devices should be controlled by PC.
We recommend to focus on the power supply, which is intended to control the
load via the Share Bus connection. The two quadrants operation is only suitable
for constant voltage operation (CV).
Clarification:
U+
U-
I+
I-
I
II
III
IV
A combination of source and sink can only map the quadrants
I + II. This means that only positive voltages are possible. The
positive current is generated by the source or application and
the negative current flows into the load..
The maximum approved limits for the application should be set
in the power supply. This can be done via the interface. The
electronic load should preferably be in operating mode CV. The
load will then, using the Share Bus, control the output voltage
of the power supply.
Typical applications:
•
Fuel cells
•
Capacitor tests
•
Motor driven applications
•
Electronic tests where a high dynamic discharge is required.
3.10.3.2 Connecting devices to a 2QO
There are a number of possibilities to connect source(s) and sink(s) to make a 2QO:
Share-Bus
E.U.T
E-LOAD
PSU
Configuration A:
1 e-load and 1 power supply, plus 1 test object (E.U.T).
This is he most common configuration for 2QO. The nomi
-
nal values for U,I and P of the two devices should match,
such as ELR 9080-170 and PSI 9080-170 3U. The system
is controlled by the power supply, which has to be set to be
“Master” in the setup menu, even though there is no master-
slave operation running.
E.U.T
E-LOAD
PSU 1
PSU n
M
ast
er
-S
lave
SB
Share-Bus
Configuration B:
1 e-load and multiple power supplies, plus 1 test object
(E.U.T).
For adapting the total power of the power supply device to
the possibly higher input power of the load, the power sup
-
plies are connected via Master-Slave and the load’s current is
shared across the power supplies when wiring the Share bus
to gain a balanced load distribution. The digital master-slave
bus can be wired if installed on the power supply units. One
PSU, preferable PSU 1, has to be set to Master for the Share
bus connection, no matter if MS operation via the digital MS
bus used or not.
