LETRIKA 260 User Manual
USER MANUAL
SOLAR
MICRO INVERTER 260
2
USER MANUAL
Copyright
Trademarks
Who should read this manual
Disclaimer of liability
All rights with respect to this document, including applications for patent and registration of
other industrial property rights, are reserved. Unauthorized use, in particular reproduction or
making available to third parties, is prohibited.
Letrika Sol d.o.o. is registered trademarks of the Mahle Letrika d.o.o.. All other brand or
product names mentioned in this document may be trademarks or registered trademarks of
their respective holders.
This manual is intended to be used during installation, commissioning and maintenance as a
reference for installers, system integrators and other qualified personnel with knowledge of local
standards and regulations. They should always follow local electrical safety and fire protection
guidelines. Only technically qualified personnel should install or replace Letrika Micro inverters.
This manual only describes the product and is not a warranty of performance or characteristic.
Contents of the manual has been reviewed against the hardware and software described. Any
liability can be accepted for any errors or omissions contained in the information given.
The installation, handling and use of Letrika micro inverters are beyond company control.
Letrika Sol d.o.o. does not assume any responsibility for loss, damage, injury or expense
resulting from the improper installation, handling, use or maintenance.
We reserve the right to change this document at any time without notice.
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USER MANUAL
Introduction 4
Main features 4
PV Power Plant with Letrika Solar Micro inverters 260 5
Hardware Structure of Solar Micro Inverter 260 6
Safety 8
Symbols legend used in this manual and/or equipment 8
Safety and general warnings 8
General installation safety guidelines 9
Installation procedure 10
Compatible PV modules 10
Landscape versus portrait panels placement 11
Mounting hardware compatibility 12
Al profile selection 12
Inverter fixing screws positions 12
Inverter cooling consideration 13
Connecting cables to micro inverter 14
Connecting micro inverter system to utility grid 14
Simple single phase connection with I.P.S. device 15
Single phase connection without I.P.S. interface to grid 15
Three phase connection 16
Trunk cable extension and cable end covering 17
Commissioning 18
Preliminary checks 18
Sequence of operations 18
Troubleshooting 19
List of errors in alarm list 19
Storage 22
Disposal 22
Maintenance 22
Registration and warranty 23
Contact 23
Appendix 24
Technical specification 24
Certificate 25
Identification and oredring code 25
Dimensions 26
Compatible dc connector systems 26
Compatible AC connector system 27
Trunk cable data 27
Accessories 28
Waterproof cap 28
Cable end cap 29
Cable joiner 29
1
1.1
1.2
1.3
2
2.1
2.2
2.3
3
3.1
3.1.1
3.1.2
3.1.2.1
3.1.2.2
3.1.2.3
3.2
3.3
3.3.1
3.3.2
3.3.3
3.3.4
4
4.1
4.2
5
5.1
6
7
8
9
10
Table of contents
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USER MANUAL
1 Introduction
1.1 Main features
• Nominal Apparent Power 290 VA at power factor f 0,9
• Nominal Real Power 260W
• Nominal Reactive Power 260 VAr at power factor 0.9
• Max. Reactive Power 0-260 VAr (cap., ind.)
• Max efficiency 96,1%
• Large voltage and power input range - corresponds to the majority of 60 and 72-cells PV modules
• Reactive power capability – wide range
• Dynamic power factor
• Integrated relay for safe grid disconnection
• Galvanic isolation of DC side from AC side with HF transformer
• Low ripple current
• 0.0 W standby consumption
• WMBUS standard wireless communication
• DC circuit is isolated and insulated from ground
• Quick installation
• Full power at ambient temperature 65°C
• Die cast aluminum enclosure with completely potted electronics
• IP 67 – dust tight, no ingress of dust; immersion in water up to 1 m for 30 minutes
• Integrated foil capacitors, allowing very long life-time (25 years)
• Design flexibility
• Letrika 50 years’ experience in automotive and heavy duty electronics and electro mechanics
Protection Function
• Over and under voltage protection
• Over and under frequency protection
• Anti-Island protection
• Surge protection device (SPD) integrated
• Mains Monitoring Switching Device (MSD) integrated according to VDE 4105
INTRODUCTION
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USER MANUAL
1.2 PV Power Plant with Letrika Solar Micro inverters 260
PV power plant with Letrika Solar Micro inverters 260
consists of several components. PV module directly
convert sunlight into DC electricity, micro inverters
change electrical current from DC to AC. Electricity is then
transferred via, trunk cables, junction boxes and main
distribution switch to the grid .
Each PV module is directly connected to Letrika Solar Micro
inverter 260. PV module and micro inverter is individual
power unit operating at maximum available power. The
operation of such power unit is independent and does not
affect the operation and performance of other power units.
PV modules of different characteristic can be installed in
different position and orientation without interfering with
each other.
The operation of micro inverters can be controlled via Linux
based Gateway. Gateway communicates over wireless
WMBUS with Letrika Solar micro inverter 260 and over a
Wi-Fi or Ethernet with computer, smart phone or tablet.
We can monitor and analyze individual micro-inverters or
the whole power plant using browser on computer, smart
phone or tablet.
INTRODUCTION
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USER MANUAL
Solar Micro inverter converts direct current (DC) generated from a single PV module to alternating current (AC).
Each micro inverter use Maximum Power Point Tracking (MPPT) to maximize production of single PV module.
Micro inverter has several functional units:
Input filter on DC side decouples PV panel from high
frequency transients during DCDC converter switching.
DC side power supply of the primary (DCDC) logic is active
until minimum panel voltage is reached.
Primary DSP controller (16bit , 70MIPS, high performance
DSP) calibrates analog system, then starts to sample
PV panel open circuit voltage. After PV voltage reaches
sufficient voltage for reliable start of main flyback power
supply, secondary(AC) side logic is turned on.
At this point, power supply to both power sections is
activated, secondary DSP (32bit,60Mips controller) is
started.
After successful connection with primary DSP controller,
secondary controller will execute auto calibration and
after 10 seconds activate WMBUS RF module. This delay
is necessary for WMBUS module to stabilize operating
parameters and also to avoid unnecessary power ON/OFF
INTRODUCTION
1.3 Hardware Structure of Solar Micro Inverter 260
cycling in case of low irradiation. WMBUS module converts
inverter serial data into 868Mhz data stream according to
WMBUS standard. Data from micro inverter can be received
by Letrika data gateway or by any device compatible with
WMBUS standard.
The power DCDC converter is started in constant current
mode and high voltage. Energy storage capacitor is charged
up to minimum voltage needed for reliable start. Voltage
level in energy storage capacitor changes with grid voltage,
optimizing switching losses on power section. Foiled
capacitors are use because they have lower aging compared
with electrolytic capacitors.
Concurrently DSP2 algorithms are synchronized with grid
and operating limits are checked. Once DC voltage reaches
minimum level, AC inverter power stage is enabled, grid
disconnection relay (if present) is turned on and grid current
is gradually (according to standards limits) increased.
DCDC converter switches to MPPT tracker mode and begins
to track PV panel maximum power point. A high speed
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USER MANUAL
INTRODUCTION
processor with special algorithm is used to achieve high
efficiency and best possible harvest from sun.
Differential mode filters are used for filtering 50 Hz current
from inverter carrier frequency,, .
Common mode EMC filters are used for EMC interferences
filtering. THD for
Surge and Burst protections are used for protecting inverter
from lightening phenomena’s and grid over voltages. It
is strongly recommended to install external overvoltage
protection class II on AC side, it is also condition for the
validity of Limited Warranty.
Solar Micro inverter is in standby until there is insufficient
irradiance and a specific minimum voltage is present in
the inverter. The consumption in standby is 0W. The micro
inverter starts to fully operate when the sun begins to
supply energy and the voltage in PV module reach 22Vdc.
When the voltage drops below the minimum voltage value
(15Vdc) feed-in mode ends and the inverter switches off.
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USER MANUAL
SAFETY
2 Safety
CAUTION
Generic danger - Important safety
information.
WARNING
Dangerous voltage. All precautions and protections against high voltage electric shock
should be taken.
HOT
SURFACE
Danger of burns, do not touch product.
WARNING
Letrika inverters must be installed only by
technically qualified personal.
WARNING
All electrical installations must be performed
in accordance with local and national electrical
standards and codes.
WARNING
Do not connect wet connectors. Connectors must
be dry before any attempt to connect them.
WARNING
Do not cut, bend or modify original connectors
and/or cables supplied with inverters.
WARNING
Lightning protection must be placed on each
inverters branch. Avoid wiring loops or rings.
Keep cable paths short as possible.
WARNING
Inverter and all metal components must be
grounded according to local standards.
2.1 Symbols legend used in this manual and/or equipment
2.2 Safety and general warnings
WARNING
Inverter PV side is galvanically separated from
dangerous voltages; however do not attempt
to disconnect PC cables from inverter during
operation.
WARNING
Always mount grid disconnection switch between micro inverter installation and grid.
WARNING
There are no user serviceable parts inside
Letrika micro inverter. It is strictly forbidden
any intervention on micro inverter internal
structure.
CAUTION
In case of fault on PV installation with Letrika
micro inverters, do not attempt disconnect PV
or grid cables from inverters or junction boxes
until qualified personal checks the installation.
HOT
SURFACE
Metal surface of Letrika micro inverters can reach
more than 70 degrees in operation. To reduce
risk of burns do not touch the inverter while in
operation. After switching o micro inverter wait
at least 10 minutes before touching it.
Manual shall be consulted that must be
available for future use and not damaged.
Connection to ground protection.
Note. Please read paragraph marked with
this icon carefully.
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USER MANUAL
SAFETY
CAUTION
Grounding of all metal parts of the
construction is the responsibility of
installer.
WARNING
Micro inverters generates power from more
than one source
WARNING
When micro inverter is connected to PV
module and exposed to light, dangerous
voltages may appear on output in case of
malfunction.
WARNING
Inverters with damaged enclosure or wiring
must not be repaired and must be returned
to producer
WARNING
It is forbidden to connect DC input of micro
inverter to the battery or any other DC
power supply. Solar micro inverter can be
connected only to PV module.
2.3 General installation safety guidelines
WARNING
Use only originally supplied cables. Use
original end cap from ALTW cable producer
to ensure IP67 protection on whole cable
trunk.
CAUTION
Connect circuit breaker with overcurrent
protection according to PV plant power and
local standards.
CAUTION
Always fix cables to the frame. Do not allow
PV and grid cables to float free.
CAUTION
If equipment is not used as specified in
this manual and other Letrika documents,
protection provided by the equipment may
be impaired.
The installation must be wired according to local regulations
and standards where inverters are mounted.
Follow local guidelines for grid monitoring devices and other
safety devices to be located between inverters and grid.
CAUTION
If required by local standards, AC wiring must
be additionally protected with RCDs and Earth
Fault Monitors where required.
CAUTION
Before starting inverters for first time, inspect
the wiring, measure isolation resistance between PV+,PV- and protective ground.
CAUTION
Micro inverters should be mounted on
aluminum frame holding the PV modules.
Preferably on upper side to avoid prolonged
submersion of inverters into water or snow. Do
not left inverters unfixed on the roof.
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