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ELR 9000 Series
3.10.3 Two quadrants operation (2QO)
3.10.3.1 Introduction
This kind of operation refers to the use of a source, in this case a power sup-
ply from a compatible series (see section
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 test, or a motor by clipping
excess energy with the sink.
The user can decide either to operate the system manually or only the power
supply device as the driving unit or to control both devices by PC. It is recom-
mended to focus on the power supply, which is intended to control the load
via the Share Bus connection. The 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 set values for current and power of the load need to be set
to match the application’s requirements. This can be done manu-
ally or via any interface. The power supply has to be operating
in mode CV. Only then it will control the input voltage of the load
using the Share Bus.
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:
1x e-load and 1x power supply, plus 1x test object (E.U.T).
This is the most common configuration for 2QO. The nominal
values for U,I and P of the two devices should match, such
as ELR 9080-170 und PSI 9080-170 3U. The characteristics
of the 2QO system is determined by the power supply, which
has to be set to “Master” in the setup menu, even if 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:
1x e-load and multiple power supplies (or vice versa), plus
1x test object (E.U.T).
For adapting the total power of the source to the possibly higher
input power of the load, the power supplies 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 addition-
ally. 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.