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

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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

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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.

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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.

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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.

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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

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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

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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

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Notes The user sets the full scale in engineering units (bar) on the operator interface corresponding to the sensor full scale In the reservoir

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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

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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)

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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

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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

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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

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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

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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’.

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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)

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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.

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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

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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

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