User Manual

Page 76
PSI 9000 3U Series
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3.9.3 Two quadrant operation (2QO)
3.9.3.1 Introduction
This way of operating refers to the use of a source, in this case a power supply
of, for example, series PSI 9000 3U, and a sink, in this case 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nal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).
Clarication:
U+
U-
I+
I-
III
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ows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.
3.9.3.2 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
Conguration A:
1 e-load and 1 power supply, plus 1 test object (E.U.T).
Thisisthemostcommoncongurationandtheleastprob-
lematic.
The nominal values for U,I and P of the two devices should
match, such as ELR 9080-170 und PSI 9080-170 3U.
Share-
Bus
E.U.T
E-LOAD PSU 1
PSU n
Master-Slave
Conguration B:
1 e-load and multiple power supplies, plus 1 test object
(E.U.T).
For adapting the total power of the power supply on the pos-
sible higher input power of the load. The power supplies are
connected via Master-Slave and the load current is shared
across the power supplies.