System and method for enhanced watch dog in solar panel installations
A system and method for automated shutdown, disconnect, or power reduction of solar panels. A system of solar panels includes one or more master management units (MMUs) and one or more local management units (LMUs). The MMUs are in communication with the LMUs with the MMUs and LMUs “handshaking” when the system is in operation. The MMUs are connected to one or more controllers which in turn are connected to emergency detection sensors. Upon a sensor detection of an emergency, the associated MMU is notified which in turn instructs associated LMUs to take appropriate action. In the event that communication with the MMUs has been cut off, the LMUs take the initiative to shut down, disconnect, or reduce the output of associated string(s) of solar panels.
1. A watchdog unit comprising:
connectors to couple the watchdog unit between a solar module and a power bus, the power bus configured to connect a plurality of solar modules to an inverter;
a local controller configured to monitor a communication sent on the power bus from a central controller remote from the solar module and determine whether the communication has been interrupted for a time period longer than a number of allowed skips; and
at least one switch configured to disconnect the solar module from the power bus in response to a determination by the location controller that the communication from the central controller has been interrupted for a time period longer than the number of allowed skips;
wherein the watchdog unit is configured to connect the solar module to the power bus when the communication is not interrupted.
2. The watchdog unit of claim 1 , further comprising a junction box housing the watchdog unit, the junction box to provide connectivity between the solar module and the power bus.
3. The watchdog unit of claim 2 , wherein the local controller is configured to control a duty cycle of the switch to control an output voltage from the junction box.
4. The watchdog unit of claim 3 , wherein the local controller is configured to operate using power from the solar module.
5. The watchdog unit of claim 1 , further comprising a bypass circuit configured to enable current in the power bus to bypass the solar module when the switch disconnects the solar module from the power bus.
6. The watchdog unit of claim 1 , wherein the watchdog unit is configured to determine irregularity in periodicity of the communication to determine whether the communication is interrupted.
7. The watchdog unit of claim 1 , wherein the communication is interrupted when a threshold of irregularity is surpassed.
8. The watchdog unit of claim 1 , wherein the communication is interrupted when the central controller fails to send the communication.
9. The watchdog unit of claim 1 , further comprising the solar module; and a junction box coupled with the solar module to provide connectivity to the power bus, wherein the watchdog unit resides in the junction box.
10. The watchdog unit of claim 1 , further configured to disconnect the solar module from the power bus when the watchdog unit receives a shutdown signal.
11. The watchdog unit of claim 1 , wherein the watchdog unit wirelessly communicates with the central controller.
12. A watchdog unit comprising: connectors to couple the watchdog unit between a solar module and a power bus, the power bus configured to connect a plurality of solar modules to an inverter, the watchdog unit configured to: verify communication with a central controller remote from the solar module; and shutdown the solar module from the power bus if communication with the central controller cannot be verified for a time period longer than a number of allowed skips.
13. The watchdog unit of claim 12 , wherein to shutdown the solar module entails disconnecting the solar module from the power bus.
14. The watchdog unit of claim 12 , wherein to verify communication: a challenge is sent to the central controller; and a response to the challenge is received.
15. The watchdog unit of claim 12 , wherein to verify communication, a communication is received within a set time from when a last communication was received.
16. The watchdog unit of claim 12 , further configured to shutdown the solar module if a shutdown signal is received.
17. The watchdog unit of claim 12 , further configured to wait for a restart signal.
18. The watchdog unit of claim 12 , further configured to draw energy from a backup energy source when a primary energy source is not available.
19. A computer-implemented method comprising: monitoring, via a computing device, a signal from a central controller remote from the computing device;
determining, via the computing device, if the signal has been lost; disconnecting, via the computing device, one or more solar modules from a power bus if the signal has been lost, the power bus configured to connect a plurality of solar modules to an inverter;
waiting, via the computing device, for a restart signal; and connecting, via the computing device, the one or more solar modules to the power bus when the restart signal is received.
20. The method of claim 19 , further comprising: enabling, via the computing device, a bypass circuit when the one or more solar modules are disconnected from the power bus, so that current continues to flow in the power bus.