System and method for enhanced watch dog in solar panel installations

• US 8,823,218 B2
• Filed: 04/22/2011
• Issued: 09/02/2014
• Est. Priority Date: 11/02/2007
• Status: Active Grant

• Current Assignee: Tigo Energy, Inc
• Original Assignee: Tigo Energy, Inc
• Inventors: Hadar, Ron, Arditi, Shmuel, Bickford, James
• Primary Examiner(s): Deberadinis, Robert L.
• Application Number:
  US13/092,783
• Publication Number:
  US 20110218687A1
• Time in Patent Office: 1,229 Days
• Field of Search: 307/151
• US Class Current: 307/151
• CPC Class Codes: G01R 31/00 Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere measuring superconductive properties G01R33/1238; testing or measuring semiconductors or solid state devices during manufacture H01L22/00; testing line transmission systems H04B3/46
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02S 50/00 Monitoring or testing of PV systems, e.g. load balancing or fault identification
• CPC Class Codes: H02S 50/10 Testing of PV devices, e.g. of PV modules or single PV cells testing of semiconductor devices during manufacturing H01L22/00
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

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 shutdown, disconnect, or reduce the output of associated string(s) of solar panels.

Claims

1. A system comprising:

a master management unit (MMU); and

a local management unit (LMU) in communication with the master management unit (MMU), the LMU controlling one or more solar modules;

wherein the MMU is connected to at least one sensor, the sensor configured to detect an anomaly; and

wherein upon detection of the anomaly by the sensor, the MMU sends a command to the LMU to alter the state of an associated solar module; and

wherein upon receiving a command from the MMU, the LMU alters the state of the one or more solar modules in accordance with command.

2. The system of claim 1, wherein the MMU queries the sensor for the anomaly.

3. The system of claim 1, wherein the sensor notifies the MMU of the anomaly.

4. The system of claim 1, wherein the command is selected from the group consisting of:

a command to shutdown the module;

a command to disconnect the module; and

a command to alter the output of the module.

5. The system of claim 1, wherein:

the MMU is connected to a network; and

the sensor is connected to the network.

6. The system of claim 1, further comprising:

a watchdog unit to monitor a communication in a solar array between the master management unit (MMU) and a respective local management unit (LMU);

wherein if the communication is interrupted between the MMU and the respective LMU, the watchdog unit sends polls to the MMU up to a specified number of times;

wherein if the watchdog unit receives no response after completing the polls, receives a command to modify operation of a solar module, or receives an inappropriate response, then the watchdog unit issues an instruction to the respective LMU to modify operation of the solar module.

7. The system of claim 6, wherein the respective LMU comprises the watchdog unit.

8. The system of claim 6, wherein the instruction is selected from the group consisting of an instruction to shut off the solar module, an instruction to disconnect the solar module from the solar array, and an instruction to reduce the output power of the solar module.

9. The system of claim 1, further comprising:

a watchdog unit coupled 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 having;

a local controller to monitor a communication from a central controller remote from the solar module and determine whether the communication is interrupted;

means to poll the central controller to determine if an interruption of the communication is transient;

at least one switch to disconnect the solar module from the power bus if the interruption of the communication is not transient;

wherein the watchdog unit is configured to connect the solar module to the power bus when the communication is not interrupted.

10. The system of claim 9, further comprising a junction box housing the watchdog unit, the junction box to provide connectivity between the solar module and the power bus.

11. The system of claim 10, wherein the local controller is configured to control a duty cycle of the switch to control an output voltage from the junction box;

and the local controller is configured to operate using power from the solar module.

12. The system of claim 9, 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.

13. The system of claim 9, wherein the watchdog unit is configured to determine irregularity in periodicity of the communication to determine whether the communication is interrupted.

14. The system of claim 9, 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.

15. A method comprising:

monitoring a sensor for an anomaly by a master control unit (MMU);

determining by the MMU if the sensor has detected an anomaly and, if the sensor has detected an anomaly, the MMU determining if the anomaly requires a control change; and

issuing a control change command to a local management unit if the anomaly requires a control change, wherein the control change command is selected from the group consisting of;

a command to shut down one or more solar modules;

a command to disconnect one or more solar modules;

a command to shut down one or more solar module strings;

a command to alter the output of a solar module;

a command to shutdown one or more LMUs;

a command to disconnect one or more LMUs

a command to shutdown an inverter;

a command to disconnect an inverter;

a command to do nothing; and

no command.

16. The method of claim 15, wherein the monitoring comprises one of:

the MMU querying the sensor for the anomaly, and the sensor notifying the MMU of an anomaly.

17. The method of claim 15, wherein:

the MMU is connected to a network; and

the sensor is connected to the network.

18. 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 there is a loss of signal;

polling, via the computing device, the central controller to determine if the loss of signal is transient;

disconnecting, via the computing device, one or more solar modules from a power bus if the loss of signal is not transient, 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.

19. The method of claim 18, 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.