SolarEdge Solar Panel Optimisers
For many years, solar professionals have been searching for ways to improve energy production from partially shaded solar PV systems.
If we can improve the performance of the system, the financial savings and environmental benefits will also be better.
Understanding the problem
Traditional solar systems are made up of a group of solar panels connected in series (on the roof or ground mounts) and joined to a solar inverter on the ground level. This is known in the solar industry as a string inverter based system.
Because each panel is series connected to the one next to it, it is possible for several problems to occur in partly shaded conditions. This effect has the simple name of ‘the christmas tree light effect’, with symptoms detailed as follows:
- shaded panels may prevent current from other productive panels from passing through (older panels); leading to
- mismatch between panel currents, causing hotspots; and
- bypass diodes in shaded modern panels may activate, bypassing the shaded panel completely and dropping the voltage. In smaller systems, the voltage drop across several panels may be enough to cause the solar inverter to turn off, and therefore stop the whole system producing energy. The different performance of each panel in the group can also confuse the management processes of the solar inverter (management in this case being known as MPPT or maximum power point tracking).
