6
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
