U.S. Patent Number 8,289,183, titled "System and method for solar panel array analysis," covers a system and method for monitoring performance of one or more solar panels in a photovoltaic array, using a number of sensors configured to measure an output of individual solar panels.
In the patented invention, a telemetry gateway collects data from the sensors and transmits the collected data to a monitoring system. The monitoring system includes an event signature recognizer, a trend analyzer and a symmetry analyzer.
The system detects events, trends and solar panel array asymmetry. It can also display realtime graphs, proposed corrective actions and alerts via a user interface.
Solar panels use a large number of individual photovoltaic cells to convert sunlight into electrical energy. The majority of solar panels use wafer-based crystalline silicon cells or a thin-film cell based on cadmium telluride or silicon.
The PV cells are first coupled in series within a group on the panel, and a number of the groups are then coupled together in parallel. Similarly, a PV array, also referred to as solar array, is made of solar panels arranged in series and in parallel.
In a conventional solar array, all of the individual panels in the array must receive full sunlight for the array to work properly, according to the patent description. If a portion of the array is shaded or otherwise impaired, the entire array power output -- even from those sections still exposed to sunlight -- is lowered.
The electrical power generated by each solar panel is determined by the panel's voltage and current. In a solar array electrical connections are made in series to achieve a desired output string voltage or in parallel to provide a desired amount of string current source capability.
"Inevitably, efficiency reducing variations among panels exist in many solar arrays," the patent description says. "A significant amount of energy is left unrealized when these variations go undetected and uncorrected."
Inventor Andrew Foss of San Jose, Calif. filed the application for the patent on April 24, 2009.