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EPS Stromversorgung GmbH
Alter Postweg 101 • 86159 Augsburg
Germany
Fon: +49 821 / 570451-0
Fax: +49 821 / 570451-25
www.eps-germany.de
PSI 9000 2U Series
3.11.4 Two quadrant operation (2QO)
3.11.4.1 Introduction
This way of operating refers to the use of a source, in this case a power supply
of this series PSI 9000 2U, and a sink, for example a series ELR 9000 electronic
load. The source and the sink function alternately in order to test a device, such
as a battery, by deliberate charging and discharging as part of a functional 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 focous on the power supply, which is intended to control the
load’s behaviour regarding voltage and current via the Share Bus connection.
Two quadrant 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.
3.11.4.2 Connecting devices to a 2QO
There are several ways 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 the most common configuration for 2QO.
The nominal values for U and I of the two devices should
match, but at least the voltage. For example, an ELR 9080-
170 and PSI 9080-120 2U would match. The system is con-
trolled by the power supply unit, 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 1
PSU 1
Master
PSU n
E-LOAD n
Master-Slave
Share-Bus
M
as
te
r-
Sl
av
e
Configuration B:
Multiple e-loads and Multiple power supplies, plus 1 test object
(E.U.T), for raising the total performance.
The combination of load units and power supply units each
create a block, a system with certain power. Here it is also
necessary to match the nominal values, but at least the volt-
age of the two systems, i.e an 80 V DC input of the loads to a
max. 80 V DC output of the power supplies. The max. number
of 16 units cannot be exceeded. Regarding the Share bus
connection, all e-load units have to be slaves, while one of
the PSUs has to be set as master.
