Systems and methods for an enhanced watchdog in solar module installations

• US 10,312,857 B2
• Filed: 12/16/2014
• Issued: 06/04/2019
• Est. Priority Date: 09/03/2009
• Status: Active Grant

• Current Assignee: Tigo Energy, Inc
• Original Assignee: Tigo Energy, Inc
• Inventors: Hadar, Ron, Arditi, Shmuel
• Primary Examiner(s): Martin, Matthew T
• Application Number:
  US14/572,458
• Publication Number:
  US 20150101651A1
• Time in Patent Office: 1,631 Days
• 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: H01L 31/052 Cooling means directly associated or integrated with the PV cell, e.g. integrated Peltier elements for active cooling or heat sinks directly associated with the PV cells cooling means in combination with the PV module H02S40/42
• CPC Class Codes: H02S 40/32 comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules
• CPC Class Codes: H02S 40/34 comprising specially adapted electrical connection means to be structurally associated with the PV module, e.g. junction boxes
• 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: H02S 50/15 using optical means, e.g. using electroluminescence
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

Systems and methods for automatically or remotely rendering a solar array safe during an emergency or maintenance. A watchdog unit is disclosed for monitoring a signal from a central controller. If the signal is lost, interrupted, or becomes irregular, or if a shutdown signal is received, then the watchdog unit can shut down one or more solar modules. Shutting down a solar module can mean disconnecting it from a power bus of the solar array or lowering the solar module voltage to a safe level.

Claims

1. A photovoltaic system, comprising:

a power bus;

a central controller;

an inverter coupled between the power bus and a power grid; and

a plurality of photovoltaic modules, each respective photovoltaic module of the photovoltaic modules having a watchdog unit coupled between the respective photovoltaic module and the power bus, the watchdog unit comprising;

a converter configured to convert power generated by the respective photovoltaic module for the power bus;

a communication connection to the central controller;

a local controller; and

at least one switch coupled between photovoltaic cells of the respective photovoltaic module and the power bus;

wherein the local controller is configured via hardware, or software, or combination of hardware and software to;

receive, over the communication connection, a communication from the central controller;

determine whether the communication connection containing a shutdown command;

control the at least one switch to disconnect the converter from the power bus, in response to the communication containing a shutdown command;

determine whether the communication from the central controller has been interrupted for a time period longer than a predetermined number of allowed skips, when the communication contains no shutdown command;

control the at least one switch to connect the converter to the power bus, in absence of a determination by the local controller that the communication from the central controller has been interrupted for a time period longer than the predetermined number of allowed skips; and

control the converter to lower an output of the converter to the power bus to below a predetermine threshold in response to a determination by the local controller that the communication from the central controller has been interrupted for a time period longer than the predetermined number of allowed skips.

2. The photovoltaic system of claim 1, wherein the communication from the central controller is via a wired connection.

3. The photovoltaic system of claim 1, wherein the communication from the central controller is via a wireless connection.

4. The photovoltaic system of claim 1, wherein the local controller controls a duty cycle of the at least one switch to control an output voltage of the respective photovoltaic module.

5. The photovoltaic system of claim 2, wherein the local controller is powered by the respective photovoltaic module.