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 communications from a remote unit, the communications configured to cause the solar module to change from a first mode of outputting power to a second mode of being shut down from outputting power;
a controller;
a switch configured to connect the output of the photovoltaic panel for providing an operating voltage to the controller;
a first circuit path to provide power from the output of the photovoltaic panel to the controller in the first mode; and
a second circuit path to provide power from the output of the photovoltaic panel to the controller in the second mode;
wherein in the first mode, the switch is open;
wherein in the second mode, the controller causes the local management unit to shut down outputting power from the solar module, and causes the switch to close.
2. The solar module of claim 1 , wherein the communications include heartbeat signals from a central controller.
3. The solar module of claim 2 , wherein the communication module is configured to receive the heartbeat signals via a wireless communication channel.
4. The solar module of claim 2 , wherein the communication module is configured to receive the heartbeat signals via wiring connected to output terminals of the local management unit.
5. The solar module of claim 4 , wherein the local management unit includes a power converter configured to convert the input to an output on the output terminals of the local management unit.
6. The solar module of claim 2 , wherein the local management unit is configured to change from the first mode to the second mode in response to an instance of time out of the heartbeat signals.
7. The solar module of claim 1 , wherein the communications include a shutdown command from a controller remote from the solar module.
8. The solar module of claim 7 , wherein the local management unit is configured to change from the first mode to the second mode in response to the shutdown command.
9. The solar module of claim 1 , wherein the local management unit is configured to change from the first mode to the second mode after detecting a fault.
10. The solar module of claim 9 , wherein the fault is detected in power bus wiring, in a junction box, or in a head end.
11. A method implemented in a solar module, the method comprising:
generating, by a photovoltaic panel, an output;
receiving, in a local management unit connected to the photovoltaic panel, the output as input, the local management unit having a controller and a communication module to receive communications from a remote unit, the communications configured to cause the solar module to change from a first mode of outputting power to a second mode of being shut down from outputting power;
providing power using a first circuit path from the output of the photovoltaic panel to the controller in the first mode;
providing power using a second circuit path from the output of the photovoltaic panel to the controller in the second mode, wherein a switch connects the output of the photovoltaic panel to provide an operating voltage to the controller; and
causing, by the controller in the second mode, the local management unit to shut down outputting power from the solar module, and to close the switch.
12. The method of claim 11 , wherein the communications include heartbeat signals from a central controller.
13. The method of claim 12 , wherein the communication module is configured to receive the heartbeat signals via a wireless communication channel.
14. The method of claim 12 , wherein the communication module is configured to receive the heartbeat signals via wiring connected to output terminals of the local management unit.
15. The method of claim 14 , wherein the local management unit includes a power converter configured to convert the input to an output on the output terminals of the local management unit.
16. The method of claim 12 , wherein the local management unit is configured to change from the first mode to the second mode in response to an instance of time out of the heartbeat signals.
17. The method of claim 11 , wherein the communications include a shutdown command from a controller remote from the solar module.
18. A system, comprising:
a remote unit; and
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 communications from the remote unit, the communications configured to cause the solar module to change from a first mode of outputting power to a second mode of being shut down from outputting power;
a controller;
a switch configured to connect the output of the photovoltaic panel for providing an operating voltage to the controller;
a first circuit path to provide power from the output of the photovoltaic panel to the controller in the first mode; and
a second circuit path to provide power from the output of the photovoltaic panel to the controller in the second mode;
wherein in the first mode, the switch is open;
wherein in the second mode, the controller causes the local management unit to shut down outputting power from the solar module, and causes the switch to close.
19. The solar module of claim 1 , wherein the switch is a first switch, the local management unit further having:
a second switch configured to connect the output of the photovoltaic panel to string wiring for outputting power from the solar module;
wherein in the first mode, the controller causes the second switch to close.
20. The solar module of claim 1 , wherein:
the local management unit further has a diode; and
the first switch connects the diode to the output of the photovoltaic panel, and the diode is configured to provide a voltage drop for providing the operating voltage to the controller when in the second mode.