Circuits and methods for limiting open circuit voltage of photovoltaic strings

摘要

A photovoltaic string may include an open circuit voltage limiter that conducts current in one direction to provide a limiter voltage less than an open circuit voltage of the photovoltaic string, and that conducts current in the other direction. One or more open circuit voltage limiters may be connected across the photovoltaic string or across selected groups of solar cells of the photovoltaic string. The limiter voltage may be greater than a maximum power point voltage but less than the open circuit voltage of the photovoltaic string.

主权项

1. A photovoltaic string comprising:
a plurality of serially connected solar cells; a positive lead and a negative lead on opposite ends of the photovoltaic string, one end of the plurality of serially connected solar cells being connected to the positive lead and an opposite end of the plurality of serially connected solar cells being connected to the negative lead; an open circuit voltage limiter across a group of solar cells in the plurality of serially connected solar cells, the open circuit voltage limiter having a positive terminal connected to the negative lead and a negative terminal connected to a connection between adjacent solar cells in the plurality of solar cells, the open circuit voltage limiter having a limiter voltage less than an open circuit voltage of the group of solar cells for current flowing through the open circuit voltage limiter in one direction and allows current flow through the open circuit voltage limiter in another direction; and a bypass diode having a cathode connected to the positive lead and an anode connected to the negative lead.