Photovoltaic inverter for water pump applications TECHNICAL

Photovoltaic inverter for water pump applications TECHNICAL
Photovoltaic inverter
for water pump applications
TECHNICAL SPECIFICATION
STORE THIS DOCUMENT IN A SAFE PLACE FOR REFERENCE
During the whole life time of the equipment
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 1 di 16 + FR
CONTENTS
1
MAIN FEATURES ......................................................................................................3
2
OPERATING MODES AND APPLICATIONS .................................................................4
2.1 INVERTER ‘START’ AND ‘STOP’ SEQUENCES ......................................................................... 4
2.2 CONSTANT FLOW OPERATIONS (RESERVOIR APPLICATION) ..................................................... 5
2.2.1 "Automatic” set point regulation (MPPT) ............................................................ 5
2.2.2 "Manual” set point regulation (MAN) ................................................................. 5
2.2.3 Maximum daily pumped liquid volume limit........................................................ 6
2.2.4 Sensors used in “constant flow” operations ........................................................ 6
2.3 CONSTANT PRESSURE OPERATIONS (IRRIGATION) ................................................................. 8
2.3.1 "Automatic” set point regulation (MPPT) ............................................................ 8
2.3.2 Sensors used in “constant pressure” operations .................................................. 8
2.4 CONSTANT LEVEL OPERATIONS ....................................................................................... 10
2.4.1 Sensors used in “constant level” operations ...................................................... 10
2.5 SUMMARY LIST OF PROCESSED SIGNAL AND RELEVANT SENSORS ............................................ 12
3
USER SETTINGS ..................................................................................................... 13
4
ALARMS AND SIGNALS .......................................................................................... 14
5
INVERTER OUTPUT FILTER FOR DV/DT REDUCTION ................................................ 15
6
TECHNICAL SPECIFICATIONS TABLE ........................................................................ 16
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 2 di 16 + FR
1 MAIN FEATURES
The IdroSoleil inverter is a photovoltaic, three-phase inverter designed in combination with a
submerged or above-ground electro-pump, equipped with a three-phase asynchronous motor,
powered at 230V (phase-phase) or 400V (phase-phase), 50Hz.
It’s construction characteristics make it suitable to work in severe ambient conditions (-10°C ...
+50°C), dusty environments and outdoors.
IdroSoleil converts DC voltage input from a photovoltaic field into AC voltage to power a pump
according to an operating logic aimed to maximum power point tracking (MPPT), keeping pump
working conditions within the tolerance range.
Thanks to a scalar speed control algorithm (V/Hz), the IdroSoleil inverter is able to start the pump
at rated torque and accelerate it according to a ramp (from zero to rated speed) set by the user.
If sunlight does not permit rated pump operations, the pump can still run within a voltage and
frequency range set by the user. When conditions do not ensure operations within this range, the
pump is decelerated in ramp until fully stopped.
“Ramp” pump control prolongs expected component working life since it reduces mechanical
stress and controls peak currents on the asynchronous motor equipped with the pump.
The inverter is equipped with a “touch screen” graphic user interface used to set operating modes
(details on chapter 2) and user parameters. Main inverter electrical values are displayed (DC input
voltage and AC output voltage, real-time frequency and AC currents) and pump motor values
(rpm).
Furthermore, an RS485 communications slot is included for remote control via Modbus RTU
protocol of all main electrical measurements, status and machine alarms.
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 3 di 16 + FR
2 OPERATING MODES AND APPLICATIONS
IdroSoleil can be used in different pump applications by equipping the inverter with suitable
sensors (described below). The operating mode settings are selected through the user interface.
2.1 Inverter ‘start’ and ‘stop’ sequences
The inverter is enabled (not started!) by the following conditions being simultaneously met (‘AND
logic’) :
·
·
·
·
·
‘START’ key pressed on the user interface
EPO contact closed
‘Minimum level’ contact (‘Running dry’) closed
External ‘Start-Stop’ contact closed
DC voltage higher than the trip limit
All the above conditions, together with the conditions provided by the relevant sensors (typical of
each operating mode), enable the start sequence, during which the inverter starts to generate a
three-phase AC voltages (starting from 0V), increasing the voltage rms value, correspondingly
increasing the frequency and keeping the voltage/frequency ratio constant. This way the motor
starts to accelerate 'in torque’.
Starting from this point, inverter behaviour is determined by the previously selected and later
described operating mode.
The inverter starts the stop sequence when any one of these conditions is removed.
Once the stop sequence starts, the inverter starts to decelerate the pump in ramp until fully
stopped.
Inverter states are:
1. ‘Stand-by’ : the inverter is off. The inverter enters this state when :
· the Stop button was pressed, or
· the Start-Stop contact is open, or
· A protection tripped
2. Ready : the inverter is off but ready to start. The inverter enters this state when :
· Radiation is insufficient, or
· The ‘running dry’ contact opens, or
· Enable condition from sensors are missing (specific to each operating mode)
· The inverter ran for a certain amount of time outside the pump tolerance range (voltage
and frequency).
· An alarm triggered
3. Running : the inverter is running and powers the load. The inverter enters this state when :
· The previous state was ‘ready’, and
· The sensors (specific to each operating mode) permit to run, and
· The ‘idle’ time set by the parameter elapsed
Since numerous pump manufacturers specify a maximum number of start and stop cycles/pump
hours, a start delay can be set after which, once all the above start conditions are met, the inverter
resumes the start sequence.
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 4 di 16 + FR
If, during operations, sun radiation decreases, the inverter will control the pump in order to
decelerate it. When the frequency exits the pump tolerance range, the inverter will start the
above described stop sequence to avoid damaging the motor (usually the minimum correct
submerged pump operating frequency must be over 30Hz).
2.2 Constant flow operations (reservoir application)
In this operating mode, the inverter, reading the flow value from the sensor on the pump delivery
manifold, regulates flow in close loop to keep it as close as possible to the set point selected by the
user (in m^3/h or l/min and saved in EEPROM). Flow is controlled by the inverter by regulating
pump speed.
The typical application in this operating mode is reservoir pumping.
In this application, in addition to the tank "running dry" sensor (always included), the "Reservoir
tank full” sensor is also acquired and put in AND logic to the conditions listed in paragraph 2.1 that
start the start sequence.
If this contact opens, the inverter starts the stop sequence and signals the relevant alarm on the
display and via RS485.
After restart conditions are restored (for example, both “Running dry” and “Reservoir tank full"
contacts are closed) and after the restart delay has elapsed (set by the user and described in
paragraph 2.1), the inverter resumes the start sequence.
2.2.1 "Automatic” set point regulation (MPPT)
During operations, DC voltage will vary mainly due to :
·
·
Pump speed value (set point changes)
Available sun radiation
In “automatic” mode, the MPPT algorithm implements an operating policy aimed to guarantee
pump service continuity rather than actually maintaining the flow set point selected by the user.
For example, if the pump is in rated operating conditions to keep the set flow set point and, at a
certain time, radiation diminishes, DC voltage on the bus will tend to diminish. When DC voltage
drops under a certain threshold, the inverter can no longer guarantee rated pump operating
conditions.
At this point, the control, rather than starting the stop sequence, slows the pump (automatically
reducing the flow set point), to guarantee operations.
When the frequency and voltage range exits the tolerance limits that the inverter can deliver to
the pump, this means that there is not enough power at input from the photovoltaic field to keep
the pump operating and thus the stop sequence is started.
2.2.2 "Manual” set point regulation (MAN)
During constant flow operations the user can “manually” modify the flow set point compared to
the value set by the parameter, selecting the “MAN” mode on the user interface and using the
arrow keys on the touch screen display. When the “up” key is pressed, the flow set point is
increased. Similarly, when the “down” key is pressed, it is reduced.
If the user attempts to reduce flow under the threshold moving the pump out of the tolerance
range, the inverter does not run the command, keeping the pump running at the lower speed limit
in its operating range.
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 5 di 16 + FR
2.2.3 Maximum daily pumped liquid volume limit
The user can set a daily pumped liquid quantity limit (in litres or cubic meters) using a parameter
on the operator interface. When the control recognises that, within 24 hours, the set liquid
quantity was reached, it starts the stop sequence and does not restart until the next day.
2.2.4 Sensors used in “constant flow” operations
Sensor
Flow meter
Signal Type
Analogue
In current 4-20mA
In voltage 0-10V
Use
Retroaction for
flow regulation
Running dry sensor
Clean contact, with
hysteresis
Maximum level sensor
Clean contact, with
hysteresis
Inverter
stop/restart due to
no liquid in tank
Inverter
stop/restart due to
reservoir tank full
SP167E Rev. 01
Issue Date : 2013-07-19
Notes
The user sets the full scale
in engineering units (m^3/h
or l/min) on the operator
interface corresponding to
the sensor full scale
In the tank
In the reservoir tank
Technical Specification
Pag. 6 di 16 + FR
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 7 di 16 + FR
2.3 Constant pressure operations (irrigation)
In this operating mode, the inverter, reading the pressure value from the sensor on the pump
delivery manifold, regulates fluid pressure in close loop to keep it as close as possible to the set
point selected by the user (in bar) and saved by the inverter in EEPROM.
Pressure is controlled by the inverter by regulating pump speed.
The typical application in this operating mode is irrigation system.
The user can set a tolerance range for actual pressure around a set point (start/stop pressure
threshold). If conditions do not permit operations in this pressure tolerance range, the inverter
starts the stop sequence. The same occurs if the inverter cannot keep the pump operating in the
voltage and frequency tolerance range, for example, because input radiation is too low.
As for the previous operating mode, if the "running dry” sensor trips, the stop sequence is started.
2.3.1 "Automatic” set point regulation (MPPT)
During operations, DC voltage will vary mainly due to :
·
·
Pump speed value selected set point)
Available radiation.
In “automatic” mode, the MPPT algorithm implements an operating policy aimed to guarantee
pump service continuity rather than actually maintaining the pressure set point selected by the
user. For this reason, a pressure threshold (stop minimum) is set in addition to the pressure set
point.
For example, if the pump is in rated operating conditions to keep the selected pressure set point
and, at a certain time, sun radiation diminishes, DC voltage on the bus will tend to diminish. When
DC voltage drops under a certain threshold, the inverter can no longer guarantee rated pump
operating conditions.
At this point, the control, rather than starting the stop sequence, slows the pump (automatically
reducing the pressure set point), to guarantee operations.
When actual pressure exits the pressure range set by the user or the frequency and voltage range
that the inverter can deliver to the pump exits the tolerance limits, this means that there is not
enough power at input from the photovoltaic field to keep the pump operating and thus the stop
sequence is started.
2.3.2 Sensors used in “constant pressure” operations
Sensor
Pressure meter
Signal Type
Analogue
In current 4-20mA
In voltage 0-10V
Use
Retroaction for
pressure regulation
Running dry sensor
Clean contact, with
hysteresis
Inverter
stop/restart due to
no liquid in tank
SP167E Rev. 01
Issue Date : 2013-07-19
Notes
The user sets the full scale
in engineering units (bar) on
the operator interface
corresponding to the sensor
full scale
In the reservoir
Technical Specification
Pag. 8 di 16 + FR
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 9 di 16 + FR
2.4 Constant level operations
In this operating mode, the inverter, reading the liquid level from the sensor in the tank (or well),
regulates the level in close loop to keep it as close as possible to the set point selected by the user
(in metres) and saved by the inverter in EEPROM. Level is controlled by the inverter by regulating
pump speed.
The typical application for this operating mode is water collection well where, over time, liquid
flow values change and there are significant variations between input and output flow due to
different events (for example, during a rainy period, the well tends to fill). The addition of an
inverter able to regulate the level of liquid in the well avoids numerous start and stop pump cycles,
with benefits on its working life and avoiding “saw tooth” effects on pumped flow, typical of “onoff” operations.
The user can set a tolerance range for the level around a set point (start/stop level thresholds). If
conditions do not permit operations in this level tolerance range, the inverter starts the stop
sequence. The same occurs if the inverter cannot keep the pump operating in the voltage and
frequency tolerance range, for example, because sun radiation is too low.
2.4.1 Sensors used in “constant level” operations
Sensor
Level meter
Signal Type
Analogue
In current 4-20mA
In voltage 0-10V
Use
Retroaction for
level regulation
Running dry sensor
Clean contact, with
hysteresis
Inverter
stop/restart due to
no liquid in tank
SP167E Rev. 01
Issue Date : 2013-07-19
Notes
The user sets the full scale
in engineering units
(meters) on the user
interface corresponding to
the sensor full scale
In the tank (or well)
Technical Specification
Pag. 10 di 16 + FR
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 11 di 16 + FR
2.5 Summary list of processed signal and relevant sensors
Signal Type
Digital Input
(contact)
Use
Start (closed) – Stop
(open)
Application
All
Digital Input
(contact)
EPO (on if open)
All
Digital Input
(contact)
Digital Input
(contact)
Running dry
(on if open)
Maximum level
(on if open)
All
Analog Input
4-20mA/0-10V
Analog Input
4-20mA/0-10V
Measures flow or
level
Measures pressure
Flow control
Level control
Pressure control
SP167E Rev. 01
Issue Date : 2013-07-19
Flow control
Notes
Along with other conditions, it
enables the inverter. The
inverter actually starts if there
are sufficient radiation
conditions and if the various
contacts (see below) are
“closed”.
Cuts off, in any case and
Immediately, pump power (left
in free rotation).
The various Enable conditions
go in “AND” logic. Signals if the
tank reached max water level
Technical Specification
Pag. 12 di 16 + FR
3 USER SETTINGS
Parameter name
Operating voltage
(230/400V)
Operating Mode
All
Minimum operating
frequency (0-51Hz)
All
Operating mode
selection
-
Inverter idle time
after stop sequence
All
Flow measurement
unit selection
Flow measurement
fullscale
Flow measurement
fullscale (bar)
Level measurement
fullscale (m)
Number of restarts
after protection
triggers
Constant flow
SP167E Rev. 01
Issue Date : 2013-07-19
Parameter function
Inverter AC output rated voltage
setting. Setting this parameter
automatically sets DC stop
voltage thresholds for
insufficient radiation (see
technical specifications table)
Minimum AC output Frequency
threshold settings. If the inverter
is not able to guarantee the
minimum operating frequency,
the stop sequence is started to
protect the pump.
Constant flow
Constant pressure
Constant level
Time set before the inverter
restarts the start sequence
after a top. This parameter
depends on the number of
pump cycles/hours.
Selection between m^3/h and
l/min
Default
230V
Before entering “stand by” (that
requires manual reset), the
inverter must enter protection
mode for the number of times
set in this parameter
consecutively in 5 minutes.
3
30Hz
Constant flow
5 minutes
m^3/h
Constant flow
Constant
pressure
Constant level
All
Technical Specification
Pag. 13 di 16 + FR
4 ALARMS AND SIGNALS
The alarms and signals summarised in the following table are displayed an available on RS485
serial via Modbus protocol.
Alarm-Protection Name
Desaturation (protection)
Over current (protection)
Inverter Over temperature
(protection)
Action
Restart after a settable period
of time and within a maximum
number of attempts (settable).
After maximum number of
attempts, inverter in “stand
by”, fault led on.
as desaturation
Inverter in ‘Stand-by’ and fault
led on
Low sun radiation (fault)
Inverter in “ready”, awaiting
idle time
DC bus over voltage
(protection)
Inverter in ‘Stand-by’ and fault
led on
EEPROM communication error
(protection)
No DPS signalling
communication (protection)
“Running dry” contact
triggered (all operating modes)
(alarm)
Inverter in ‘Stand-by’ and fault
led on
Inverter in ‘Stand-by’ and fault
led on
Inverter ‘ready’.
Pumped quantity of liquid
reached (constant flow
operations)
(alarm)
"Maximum level” contact
triggered (constant flow
operations only)
(alarm)
Pressure fault (constant
pressure operations only)
(alarm)
EPO triggered
(protection)
Inverter ‘ready’.
SP167E Rev. 01
Issue Date : 2013-07-19
Inverter ‘ready’.
Inverter ‘ready’.
Inverter “disabled”
Reset
Reset from ON-OFF keyboard
(after the inverter entered
“stand by” and fault led is on).
as desaturation
Restart as soon as
temperature conditions are
restored.
Restart after idle time if DC
voltage is over minimum
threshold.
Reset from ON-OFF keyboard
(after the inverter entered
“stand by” and fault led is on).
Replace control board
Replace control board
Restart after the “running dry”
contact changes state and the
set amount of time has
elapsed.
Inverter stop and restart the
next day
Restart after the “tank full”
contact changes state and a
set amount of time has
elapsed.
Pressure regulation out of set
range. Restart after a settable
amount of time.
Restart after the “EPO”
contact changes state and
reset pressed on keyboard
(ON-OFF)
Technical Specification
Pag. 14 di 16 + FR
5 INVERTER OUTPUT FILTER FOR DV/DT REDUCTION
It is best to use shielded wires to connect the inverter and pump.
If wires are more than 35 … 40m long, a sinusoidal output filter, available separately, must be
installed on the inverter. In fact, inverter PWM voltage rising edges (around 0,5us), due to
reflections due to mismatch between typical wire impedance and motor input impedance, if not
suitably filtered, would cause grounding over voltage on motor input terminals, damaging winding.
The sinusoidal filter also helps to reduce common voltage disturbances, often cause of
interference with signals from sensors and on communications.
The filter is contained in a specific “connection box” to be connected under the inverter base.
SP167E Rev. 01
Issue Date : 2013-07-19
Technical Specification
Pag. 15 di 16 + FR
6 TECHNICAL SPECIFICATIONS TABLE
Model
10
15
20
25
30
40
50
35
40
49,7
44
50
62,1
115
66
143
83
1. DC side input – recommended module power
Minimum [kWp]
Rated [kWp]
Maximum [kWp]
Mppt voltage [V]
8
10
12,7
12
15
18,9
29
17
44
25
Max V voltage (at -10°C)
Min V voltage (at +70°C)
I max. of modules [A] Vac 230V
I max. of modules [A] Vac 400V
No. of DC inputs
17,5
22
27
20
25
30
25,1
31,3
37,5
350-700 for 230Vac inverter
540-750 for 400Vac inverter
780 @ 230V / 900 @ 400V
330 for 230Vac inverter
540 for 400Vac inverter
58
72
87
34
42
50
1
2
2. AC side output
Rated power [kW]
Connection
Phase-phase rated voltage Vn [V]
Rated current [A] 230Vac
Maximum current [A] 230Vac
Rated current [A] 400Vac
Maximum current [A] 400Vac
Operating voltage [V]
Operating frequency [Hz]
Maximum efficiency [%] Vac 230V
@ 400VDC
Maximum efficiency [%] Vac 400V
@ 600VDC
8,3
12,5
73,8
88,6
42,5
50,9
98,4 123,1
118,1 147,7
56,6 70,8
67,9 84,9
95.8
16,7
20,8
Three-phase
230 or 400
49,2
61,5
59,1
73,8
28,3
35,4
34,0
42,5
0 … Vn
0 … 50Hz
96.2
96.4
24,6
29,5
14,2
17,0
36,9
44,3
21,2
25,5
95
95,3
96.5
97.1
97.1
96.1
96.5
96.8
97.4
97.4
32
32
96.7
25
33,3
41,7
3. Other data
Ventilation system
Dissipated power without load [W]
Control
Output wave form
Operating temperature
Storage temperature
Inverter dimensions (LxWxH) mm
Inverter weight [kg]
Connection box filter dimensions
(LxWxH) mm
Connection box filter weight [Kg]
Maximum relative humidity
SP167E Rev. 01
Issue Date : 2013-07-19
32
32
Forced Air
32
32
32
Digital
PWM Sinusoidal
-5Ԩ / +45Ԩ
-20°C / +50°C
700x270x610
44
700x270x400
25
95% with no condensation
700x270x700
53
30
Technical Specification
Pag. 16 di 16 + FR
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