© EPS Stromversorgung in 2022, this information is subject to change without notice
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30000800_manual_psb_10000_4u_30kw_en_04
3.
Operation and application
3.1
Terms
The device is a combination of a power supply and an electronic load. It can work alternately in one of two superior operation
modes which are distinguished from each other in several parts of this document below:
•
Source / source mode:
•
the device works as a power supply, generating and providing DC voltage to an external DC load
•
in this mode, the DC terminal is considered as DC output
•
Sink / sink mode:
•
the device works as an electronic load, sinking DC energy from an external DC source
•
in this mode, the DC terminal is considered as DC input
3.2
Important notes
3.2.1
Personal safety
•
In order to guarantee safety when using the device, it’s essential that only persons operate the device
who are fully acquainted and trained in the required safety measures to be taken when working with
dangerous electrical voltages
•
For models which can generate a voltage which is dangerous by contact, or is connected to such, the
included DC terminal cover, or an equivalent, must always be used
•
Read and follow all safety warnings in section
3.2.2
General
•
When running the device in source mode, unloaded operation is not considered as a normal operation
mode and can thus lead to false measurements, for example when calibrating the device
•
The optimal working point of the device is between 50% and 100% voltage and current
•
It’s recommended to not run the device below 10% voltage and current, in order to make sure technical
values like ripple and transient times can be met
3.3
Operating modes
A power supply is internally controlled by different control or regulation circuits, which shall bring voltage, current and power
to the adjusted values and hold them constant, if possible. These circuits follow typical laws of control systems engineering,
resulting in different operating modes. Every operating mode has its own characteristics which is explained below in short
form.
3.3.1
Voltage regulation / Constant voltage
Voltage regulation is also called constant voltage operation (
CV
).
The voltage on the DC terminal of the device is held constant on the adjusted value, unless the current or the power accord-
ing to P = U
DC
* I reaches the adjusted current or power limit. In both cases the device will automatically change to constant
current or constant power operation, whatever occurs first. Then the voltage can’t be held constant anymore and will sink (in
source mode) or rise (in sink mode) to a value resulting from Ohm’s law.
CV is available for both, sink and source mode, and primarily depends on the relation between voltage set value and voltage
level on the DC terminal. The device will switch between both modes seamless when adjusting voltage. In source mode, the
output voltage in CV mode is equal to the setting while in sink mode the setting must always be lower than the input voltage
in order to have the device draw current.
While the DC power stage is switched on and constant voltage mode is active, the condition “CV mode active” will be indicat-
ed on the graphics display by the abbreviation
CV
and this message will be passed as a signal to the analog interface, as well
stored as status which can also be read as a status message via digital interface.
3.3.1.1
Voltage regulation peaks (source mode)
When working in constant voltage regulation (CV) and source mode the device’s internal voltage regulator requires a small
transient time to settle the voltage after a load step. Negative load steps, i.e. high load to lower load, will cause the output
voltage to overshoot for a short time until compensated by the voltage regulator. The time it takes to settle the voltage can
be influenced by switching the voltage regulation speed between the settings
Slow
,
Normal
and
Fast
, whereas Normal is the
default. Setting
Slow
will result in a higher transient time and higher voltage drop, but less overshooting, while
Fast
is vice
versa. Also see
“3.3.7. Dynamic characteristics and stability criteria” and “3.5.3.1. Sub menu “Settings””.
