Systems and methods for remote or local shut-off of a photovoltaic system
Systems and methods for shut-down of a photovoltaic system. In one embodiment, a method implemented in a computer system includes: communicating, via a central controller, with a plurality of local management units (LMUs), each of the LMUs coupled to control a respective solar module; receiving, via the central controller, a shut-down signal from a user device (e.g., a hand-held device, a computer, or a wireless switch unit); and in response to receiving the shut-down signal, shutting down operation of the respective solar module for each of the LMUs.
1. A solar module, comprising:
a photovoltaic panel having an output;
a local management unit connected to the photovoltaic panel to receive the output as input, the local management unit having:
a communication module to receive a shut-down signal;
a controller powered by the photovoltaic panel;
a circuit path connected to the output of the photovoltaic panel, the circuit path comprising
a switch controlled by the controller and
a diode connected in series with the switch;
wherein before the shut-down signal is received in the communication module, the switch is in an open state to prevent the output of the photovoltaic panel from going through the circuit path; and
wherein after the shut-down signal is received in the communication module, the controller places the switch in a closed state; and
wherein when the switch is in the closed state:
the output of the photovoltaic panel goes through the circuit path including the diode, and
the controller is powered by a voltage provided by the diode.
2. The solar module of claim 1 , wherein the local management unit further comprises a second switch controlled by the controller and coupled between the output of the photovoltaic panel and an output of the local management unit; before the shut-down signal is received the second switch is in a closed state to provide a second circuit path for power generated by the photovoltaic panel to go from the output of the photovoltaic panel to the output of the local management unit; and after the shut-down signal is received in the communication module, the controller places the second switch in an open state to disconnect the second circuit path.
3. The solar module of claim 2 , wherein the local management unit further comprises a third switch controlled by the controller and coupled between output terminals of the local management unit; after the shut-down signal is received in the communication module, the controller places the third switch in a closed state to provide a third circuit path that short circuits the output terminals; and before the shut-down signal is received the third switch is in an open state to disconnect the third circuit path.
4. The solar module of claim 1 , wherein the local management unit further comprises a third switch controlled by the controller and coupled between output terminals of the local management unit; after the shut-down signal is received in the communication module, the controller places the third switch in a closed state to provide a third circuit path that short circuits the output terminals; and before the shut-down signal is received the third switch is in an open state to disconnect the third circuit path.
5. The solar module of claim 1 , wherein the controller is configured to receive heartbeat signals from a central controller.
6. The solar module of claim 5 , wherein the shut-down signal corresponds to time out of the heartbeat signals.
7. The solar module of claim 5 , wherein the shut-down signal corresponds to a wireless signal transmitted from the central controller.
8. The solar module of claim 7 , wherein the central controller includes a push-button which when pressed, causes the central controller to transmit the wireless signal.
9. The solar module of claim 7 , wherein the central controller is controlled by a remote user device via a network connection to transmit the wireless signal.
10. A solar module, comprising:
a photovoltaic panel having an output;
a local management unit connected to the photovoltaic panel to receive the output as input, the local management unit having:
a communication module to receive a shut-down signal;
a controller;
a first circuit path to provide power from the output of the photovoltaic panel to the controller before the shut-down signal is received in the communication module; and
a second circuit path to provide power from the output of the photovoltaic panel to the controller after the shut-down signal is received in the communication module, wherein:
the second circuit path includes a switch and a diode connected in series;
the switch is controlled by the controller according to the shut-down signal to close the first circuit path; and
when the switch is closed, a voltage across the diode powered by the output of the photovoltaic panel provides power to the controller.
11. The solar module of claim 10 , wherein before the shut-down signal, the second circuit path is open; and after the shut-down signal, the second circuit path is closed.
12. The solar module of claim 10 , wherein the first circuit path is coupled from the output of the photovoltaic panel to an output of the local management unit.
13. The solar module of claim 12 , wherein the first circuit path includes a second switch controlled by the controller according to the shut-down signal to open the first circuit path.
14. A method implemented in a solar module, comprising:
receiving, as input in a local management unit connected to the photovoltaic panel, an
output from the photovoltaic panel, the local management unit having:
a communication module;
a controller;
a first circuit path; and
a second circuit path having a switch and a diode connected in series;
providing, via the first circuit path, power from the output of the photovoltaic panel to the controller before a shut-down signal is received in the communication module;
receiving, in the communication module, the shut-down signal; and
providing, via the second circuit path, power from the output of the photovoltaic panel to the controller after the shut-down signal is received in the communication module, by controlling, by the controller, according to the shut-down signal to close the switch, wherein when the switch is closed, a voltage across the diode powered by the output of the photovoltaic panel provides power to the controller.
15. The method of claim 14 , further comprising:
opening the switch before the shut-down signal is received in the communication module.
16. The method of claim 14 , wherein the first circuit path is coupled from the output of the photovoltaic panel to an output of the local management unit.
17. The method of claim 16 , further comprising:
controlling, by the controller, according to the shut-down signal to open the first path.