Systems and methods to provide enhanced diode bypass paths
Systems and methods for efficiently allowing current to bypass a group of solar cells having one or more malfunctioning or shaded solar cells without overwhelming a bypass diode. This can be done using a switch (e.g., a MOSFET) connected in parallel with the bypass diode. By turning the switch on and off, a majority of the bypass current can be routed through the switch, which is configured to handle larger currents than the bypass diode is designed for, leaving only a minority of the current to pass through the bypass diode.
1. A system comprising:
a group of series-connected solar cells;
a bypass diode connected in parallel to the group of series-connected solar cells; and
a bypass switch connected in parallel to the group of solar cells and the bypass diode, and configured to allow a bypass current to bypass:
the group of solar cells;
the bypass diode; and
a controller for turning the bypass switch on, when the bypass diode, is forward biased.
2. The system of claim 1 , wherein the controller turns the bypass switch on based on the bypass current through the bypass diode.
3. The system of claim 1 , wherein the controller turns the bypass switch on based on a voltage drop across the bypass diode, wherein the voltage drop is caused by the bypass current passing through the bypass diode.
4. The system of claim 1 , wherein the controller periodically turns the bypass switch on and off.
5. The system of claim 1 , wherein the controller:
holds the bypass switch on for a period of time;
turns the bypass switch off; and
turns the bypass switch back on when the bypass current passes through the bypass diode.
6. The system of claim 1 , wherein current passes through the bypass switch more often than current passes through the bypass diode.
7. The system of claim 1 , wherein the bypass switch is a transistor.
8. The system of claim 7 , wherein the transistor is a MOSFET.
9. The system of claim 1 , further comprising a current transformer configured to generate a power supply input voltage to a power supply when the bypass current passing through the bypass diode increases.
10. The system of claim 9 , wherein the power supply input voltage charges a capacitor of the power supply.
11. The system of claim 10 , further comprising a latch circuit configured to:
discharge the power supply into a first gate terminal and a second gate terminal, when the power supply input voltage is greater than a first voltage threshold; and
prevent the power supply from discharging into the first gate terminal and the second gate terminal, when the power supply input voltage is less than a second voltage threshold.