Power optimizer technology maximizes the solar generation of a PV system. It is achieved by regulating the performance of the modules through maximum power point tracking and modulating the output to match the performance of the string inverter.
Power optimizers are very useful in partially shaded conditions and when arrays of solar panels are laid in multiple orientations and locations and when there is a module mismatch.
Power optimizers are deployed in solar installations to isolate individual panels for maximizing overall solar performance. And though microinverters are a distinct technology, they also work in the same way of isolating the panels to improve output. When a power optimizer is integrated with a solar panel, it becomes a smart module.
A power optimizer collects the DC power from the panel and adjusts its voltage and current to match the central inverter. And then sends it to the central inverter for DC to AC conversion. Whereas the microinverter is like a power optimizer and a small inverter integrated into one component that is attached to each panel and the conversion of DC to AC power occurs at an individual panel level.
Maximum power point tracking
As the solar panels receive solar photons (sunlight) and convert them into electrons (electricity), the speeds of conversion, the operating temperatures, the current and voltage vary in the various panels. This affects the total amount of energy generated by the panels. To check this, and optimize solar production, solar strings use a technique called maximum power point tracking to surveil the output of the array and regulate the load to maintain the system’s peak output efficiency.
Solar panels generate very low voltages of around 30V which is too low to be converted into AC electricity. To increase the voltage, panels are linked together (forming a string) to match the inverter which usually works with 600V.
When shade occurs on a panel within a string of panels, it impacts the performance of the entire string because of increased resistance.
Power discrepancy between panels within a string often leads to severe power losses too. In these cases of shading and panel power mismatch, the maximum power point tracking system alters the operating point and moves the panels away from their best performance. This is a limitation that the MPPT system has due to the reason that it can work only in panels linked together in a series.
This is where power optimizers come into play. Power optimizers distribute the maximum power point tracking system to individual panels. And the DC to AC conversion happens at the central inverter level.
At the power optimizer level, DC-to-DC conversion takes place. This means that they collect the DC electricity from the panels at varying voltages and currents through their MPPT system and convert them into current and voltage that is more appropriate for the string inverter.
Installing power optimizers and a central inverter from the same manufacturer is highly advisable as this will facilitate communication between the inverter and the optimizers to make sure that the total voltage received from the panel strings matches the inverter.
So, when shade falls on a single panel in a string, its voltage would fall leading to a drop in the entire string’s voltage. The central inverter at this time would smartly adjust the other optimizers to slightly increase their voltage so that the total voltage received by the inverter remains consistent.
SolarEdge inverters are an excellent way to enhance the output of your system where shading is an issue and panels need to be mounted in a complex array design.
SolarEdge inverter systems consist of a central string inverter and power optimizers to go on the back of each panel to allow panel-level monitoring. It provides enhanced solar generation that leads to bigger financial savings and greater returns on your solar investment. The more power your system generates, the quicker your solar payback period is. SolarEdge inverters are an excellent solution to the issues of achieving maximum power from complicated solar installations and shaded panels.
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