PV system selection has always been a concern for everyone. As the inverter is the heart of the PV system, it is important to choose a suitable inverter.
I. "Single MPPT" OR "Multi MPPT
If the roof orientation is the same (the same orientation of the modules), you can use one way MPPT; if the roof orientation is not the same (different orientation of the modules or different number), use multiple MPPT tracking.
II. "Voltage Matching" OR "Power Matching"
Special Note: The inverter specifications of various manufacturers are not uniform (mainly in that the inverters with the same capacity may have different output voltage levels), therefore, when we choose an inverter, we should first look at which inverters meet the grid-connected voltage requirements, rather than just looking at whether the capacity is suitable.
If the grid is 220V single-phase, then the inverter needs to choose a single-phase grid-connected model.
If the grid is 380V three-phase power, you can choose a single camera hanging between a single fire wire and zero wire, or a three-phase inverter with an output voltage of 380V.
If the grid voltage is 6KV or 10KV high voltage electricity, a transformer needs to be added between the inverter and the grid connection point. Some foreign regions are 110V voltage also need to use transformer to match the grid voltage.
C. "Isolated" OR "Non-isolated" Inverter
Thin-film modules generally need negative grounding, which requires an inverter with electrical isolation to prevent the formation of loops in the PV system leading to inverter fry, or other system risks.
The way to achieve electrical isolation, generally through the "built-in high-frequency isolation transformer" or "the inverter outside the increase in frequency isolation transformer".
Four, shadow scanning function "important" OR "better than none"
If it is difficult to change the unreasonable design (house shading, small module spacing, etc.), Goodway inverter provides shadow scanning function, which can improve the power generation after opening for such shading.
Special reminder: Although the shadow scanning function of inverter can improve the power generation of PV system to a certain extent, the shadow shading will still bring a very big power generation loss to our PV system.
Five, "grid-connected electricity demand" OR "off-grid electricity demand"
General grid-connected photovoltaic system, can only meet the "grid-connected demand for electricity"; grid-connected photovoltaic system can not continue to work when the power grid outage. If the customer still needs electricity at this time, it belongs to the "off-grid demand", and then you need to choose the "off-grid inverter".
The common working modes of "off-grid inverter" are as follows.
①Default mode.
During the day, the PV power is sufficient, the load will be used first, the remaining power will be charged to the battery first, and the battery will be fully charged to supply power to the grid; at night, the battery power will be supplied to the load (the discharge time can be set), and the power will be supplemented by the grid.
② Off-grid mode.
No grid state or not connected to the grid, the load is all connected to the off-grid end of the energy storage machine (back-up), the load still works under the component or battery power supply.
③Economic mode.
According to the difference of grid price at different times, set different parts of the time to buy and sell electricity, also can use the grid valley electricity price time to charge the battery.
2, "off-grid inverter" configuration of photovoltaic system-specific connection method:
The energy storage machine can match any lead-acid battery or part of lithium battery, and the single unit is suitable for storing electricity in about 5kwh~25kwh.
