Optimizers or power optimizers can make a useful contribution to increasing the performance of a PV system. They can counteract losses, especially in the case of shading during the course of the day caused by trees, dormers, satellite dishes, chimneys, etc.. But optimizers can also be useful for different orientations within a string (e.g. south and southwest) and/or different inclinations (e.g. 15° and 43°).
Optimizers or power optimizers are often searched for the question: does a PV power optimizer make sense? There is no general answer to this question, which is why we would like to briefly introduce optimizers and power optimizers here and discuss the advantages and disadvantages.
Optimizers or power optimizers are connected in parallel to the module in order to influence the voltage and current via the load resistance. They adjust the output of individual or several modules to the string output.
However, there is a difference with optimizer manufacturer Solar Edge: Solar Edge specifies a fixed string voltage and adjusts the current. There are also fixed specifications for the string lengths, depending on the inverter or hybrid inverter used or planned. Solar Edge optimizers are actually only used with Solar Edge, but there is an activation device with which Solar Edge optimizers can also be used with other manufacturers.
Power optimizers are mainly used in three areas:
Now we come to the question of how useful optimizers or power optimizers are.
Increasing the performance of the system
A sensible use to increase the performance of the entire PV system (all modules unshaded) is very controversial. On the one hand, an increase in output can certainly be achieved if all modules have an optimizer or output optimizer. On the other hand, optimizers and power optimizers also require energy, as they are actually consumers and therefore reduce the additional yield through self-consumption.
If individual modules are shaded during the main part of the day, optimizers or power optimizers can be an interesting alternative. Due to the load resistance, the optimizers or power optimizers adjust the residual power of the module to the string power. This prevents the string power from being affected by the shaded module or modules. Logically, however, a small power loss must be accepted, as part of the solar module or PV system does not generate any power during the shading phase. To put it bluntly, the optimizer only tries to compensate for this loss and create a compromise. This is also how the MPP tracker of the inverter or hybrid inverter works.
Some inverter manufacturers have integrated shadow management into the device, which means that optimizers may not be required.
Different inclinations and orientations
If there are different inclinations and orientations within a string, optimizers work in a similar way to shadow management. The modules with unfavorable irradiation in the course of the sun and day are adapted to the string output of the better irradiated modules. It should be noted here that all modules in the affected string then require an optimizer. After all, only one part of the string is always in the better exposure ratio and the other part in the unfavorable one.
Optimizers or power optimizers can be useful and highly recommended under certain conditions. However, there are also constellations where it is not possible to say for sure or where they are not needed. This varies from case to case.
Do you have any questions about optimizers? We would be happy to advise you on this topic. Write to us or call us on 08726 910037.
