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SALICRU
4.3.7. Terminals for EPO.
The UPS has two terminals to install an external button of emer-
gency output shutdown (EPO).
4.3.8. Control panel.
UPS from
SLC CUBE3+
has a sophisticated control panel based on
a DSP (Digital Signal Processor) that performs as interface between
the UPS and end-user.
Each UPS is equipped with an alphanumerical LCD panel, which
automatically informs about the current status of the equipment
and electrical measurements to the end-user. It is based on a tree
menu, allowing an easy browsing through its screens.
4.3.9. Control software and communications.
AFC Control (Adaptive Feedforward Cancellation).
It consists in the use of digital resonators connected in parallel and
set to those frequencies where the consigns or perturbations to
refuse are expected.
This control technique allows doing the follow of the sinewave sig-
nals of reference of the output voltage in the inverter and input cur-
rent of the active rectifier.
It is important to highlight that the different controls of the UPS
do not operate either isolated or locally, but they interact between
them in such way that it results a global controller of coupled type.
It means operating advantages like to adapt the rectifier to the load
conditions immediately.
The digital control software works at two different levels:
4.3.9.1. Control software at low level.
•
Input three phase rectifier controller
: PFC control and bat-
tery charge loops. The structure adopted of independent control
per phase of cascade type allows managing both single phase
and three phase inputs.
The AFC control technique has been also applied, to assure a
sinewave mains currents, with a THDi < 2%, and in phase
shifting with the voltages, to balance the active power of all
the system, to accelerate its response and make it insensitive
against the load transients.
In normal conditions, the rectifier is running and charging the
batteries, controlling at any moment the charging current and
floating voltage according to the temperature of themselves.
The system is also in charge of minimising the charging current
ripple that flows through them.
When the input voltage or frequency is out of the correct op-
erating range, it is shutdown and batteries are responsible of
keeping the inverter in operation, which at the same time sup-
plies the loads connected at the output of the equipment till the
battery voltage decreases till the end of back up time.
Another important feature of the rectifier is its bidirectional ca-
pacity of operation. This allow consigning a battery discharging
current even with mains present. This quality performance will
make possible to do a battery test both in full load and no load
conditions.
•
Output three phase rectifier controller:
independent per
phase, it is easy adapted to different settings, either single
phase or three phase.
It is highlighted the use of the AFC control technique that al-
lows getting an output voltage with a THDv lower than 1,5%
with non-linear load at the output and good dynamic response
against unexpected step loads.
•
Switching algorithm of the bypass thyristors
.
•
Parallel control
: high speed communication and inverter par-
allel connection.
4.3.9.2. Managing software of the equipment.
• Managing and control of different parts.
• Visualisation software for user interface.
• Software of communication and protocol implementation.
• Managing software of parallel system.
4.3.9.3. Communications.
•
COM port to relays
: It supplies a digital signals in a dry con-
tact way, which makes possible the dialogue between the
equipment and other machines or devices.
By default the equipment is supplied with 4 signal relays with
a preset programming (see chart 2), which can be modified at
factory or by teh
S.T.S.
under request. Chart 6 shows all the
alarms that can be set to any relay. A fifth relay can be supplied
as an option and under request, which can be defined in the
purchase order.
Also there is a “shutdown” input that allows shutdown the in-
verter.
The most common use of this type of port is to supply the
needed information to the closing file software.
•
COM port RS-232 and RS-485
: By means of the same DB9
connector supplies the RS-232 and RS-485 communication
ports. They are mutually exclusive between them and they are
used to connect the UPS with any machine or device that has
this standard bus.
The
RS-232
port consists in the serial transmission of data, in
such way that it can send a lot of information through a com-
munication cable of 3 wires.
The
RS-485
, unlike other serial communication channels, it
uses 2 wires only to dialogue among the systems connected to
this network. The communication is established by sending and
receiving signals in differential mode, so it gives to the system
high immunity to the noise and long range (approx. 800m).
The used protocol is “MASTER/SLAVE” type. The computer or
IT system (“MASTER”) asks for a determined data, and the UPS
answers immediately (“SLAVE”).
4.4.
OPERATING PRINCIPLE OF AN EQUIPMENT.
UPS from
SLC CUBE3+
series is a double conversion system AC/
DC, DC/AC with sinewave output that supplies a safe protection
in extreme conditions of electrical power supply (fluctuations of
voltage, frequency, electrical noises, blackouts and mains faults,
