Systems and Methods to Combine Strings of Solar Panels

• US 20130026839A1
• Filed: 12/20/2011
• Published: 01/31/2013
• Est. Priority Date: 07/28/2011
• Status: Active Grant

• Current Assignee: Tigo Energy, Inc
• Original Assignee: Tigo Energy, Inc
• Inventors: Grana, Paul
• Granted Patent: US 9,142,965 B2
• Time in Patent Office: Days
• US Class Current: 307/71
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02S 40/36 characterised by special electrical interconnection means between two or more PV modules, e.g. electrical module-to-module connection
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/123 the energy generation units being or involving renewable energy sources
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge

Abstract

Described herein are apparatuses, systems and methods for configuring and managing the combination of strings of photovoltaic energy generators to improve the energy production performance of such generators. The strings of photovoltaic energy generators are connected to terminals in a combiner box having receptacles for receiving removable modular units of various types. Removable modular units with measurement capabilities are used in the combiner boxes to measure the direct current input provided by the strings; and in light of the measurements, the removable modular units can be selectively downgraded to simpler units that do not have measurement capabilities to reduce cost, and/or selectively upgraded to more sophisticated units that can adjust the output of the respective strings, such as upconverting the output voltage of the respective strings, to improve the performance of the strings.

Claims

1. A system comprising:

a housing;

a plurality of terminals secured to the housing and configured to receive a direct current input from photovoltaic devices;

a parallel direct current bus disposed inside the housing; and

a plurality of receptacles disposed inside the housing, wherein each respective receptacle of the plurality of receptacles is configured to receive a removable modular unit having a circuitry and to use the circuitry of the removable modular unit to connect a respective terminal of the plurality of terminals to the parallel direct current bus.

2. The system of claim 1, further comprising:

a controller disposed inside the housing and configured to communicate with the removable modular units received in the plurality of receptacles.

3. The system of claim 2, wherein the plurality of receptacles are configured to receive a plurality of different types of removable modular units, all types of which are capable of operably connecting the respective terminal to the parallel direct current bus when received in the respective receptacle.

4. The system of claim 3, wherein the plurality of different types of removable modular units include removable modular units configured to perform at least one of:

providing an electrical connection from the respective terminal to the parallel direct current bus;

measuring the direct current input received at the respective terminal;

disconnecting the respective terminal from the parallel direct current bus; and

converting the direct current input received from the respective terminal for the parallel direct current bus.

5. The system of claim 4, wherein at least one type of the plurality of different types of removable modular units received in the respective receptacle is configured to communicate with the controller.

6. The system of claim 5, wherein at least one type of the plurality of different types of removable modular units received in the respective receptacle is configured to communicate direct current measurement from the respective terminal to the controller.

7. The system of claim 5, wherein at least one type of the plurality of different types of removable modular units received in the respective receptacle is configured to disconnect the respective terminal from the parallel direct current bus based on communications with the controller.

8. The system of claim 5, wherein at least one type of the plurality of different types of removable modular units received in the respective receptacle is configured to convert the direct current received at the respective terminal to the parallel direct current bus based on communications with the controller.

9. The system of claim 2, wherein the removable modular units and the respective receptacles are configured to be operably coupled by inserting the removable modular unit into the respective receptacle, and are configured to be safely de-coupled by pulling away the removable modular unit from the receptacle.

10. The system of claim 9, wherein the removable modular unit includes a printed circuit board having electrical contacts configured to be electrically connected with the electrical contacts of the respective receptacle when the removable unit is inserted in the receptacle.

11. The system of claim 2, further comprising:

a plurality of strings of solar modules connected to the terminals to provide the direct current input, each solar module comprising a solar panel and a local control unit coupled between the solar panel and a respective string; and

a central control unit configured to communicate with the controller to control output to the parallel direct current bus.

12. A system comprising:

a removable modular unit comprising;

a printed circuit board having a set of connectors configured to provide electronic connections with connectors of a receptacle when the removable modular unit is inserted into the receptacle disposed inside a housing having a plurality of receptacles, the removable modular unit operable in each of the plurality of receptacles, wherein the plurality of receptacles are connected to a parallel direct current bus disposed inside the housing and configured to electrically separate the parallel direct current bus from a plurality of terminals secured to the housing in an absence of removable modular units in the plurality of receptacles, each of the plurality of terminals configured to receive a direct current input from a photovoltaic device; and

a circuitry connected to the connectors of the receptacle when the removable modular unit is inserted into the receptacle, the circuitry configured to connect a respective terminal of the plurality of terminals to the parallel direct current bus.

13. The system of claim 12, wherein the removable modular unit further comprises a second connector configured to provide electronic connection with a controller when the removable modular unit is inserted into the receptacle, the controller disposed inside the housing and configured to communicate with the removable modular units received in the plurality of receptacles.

14. The system of claim 13, wherein the removable modular unit, when inserted into the respective receptacle, is configured to perform at least one of:

providing an electrical connection from the respective terminal to the parallel direct current bus;

measuring the direct current input received at the respective terminal and communicating the measurement to the controller;

disconnecting the respective terminal from the parallel direct current bus based on communications with the controller; and

converting the direct current input received from the respective terminal for the parallel direct current bus based on communications with the controller.

15. The system of claim 13, wherein the modular unit further comprises at least one of:

a voltage measuring unit configured to measure the voltage output at the respective terminal and communicate the voltage measurement to the controller; and

a current measuring unit configured to measure the direct current input at the respective terminal and communicate the current measurement to the controller.

16. The system of claim 15, wherein the removable modular unit further comprises:

a conversion unit;

a disconnect switch;

a local processor configured to facilitate communication between the controller and at least one of;

the voltage measurement unit, the current measurement unit, the conversion unit, and the disconnect switch; and

a modular unit bus connecting the at least one of the voltage measurement unit, the current measurement unit, the conversion unit, and the disconnect switch, to the local processor.

17. The system of claim 12, further comprising:

a plurality of strings of solar modules connected to the terminals to provide the direct current input, each solar module comprising a solar panel and a local control unit coupled between the solar panel and a respective string; and

a central control unit configured to communicate with the controller to control output to the parallel direct current bus.

18. A method comprising:

connecting a plurality of strings of a photovoltaic device to a plurality of input terminals secured to a housing having receptacles capable of receiving removable modular units that when received in the respective receptacles, are connected between the respective input terminal and an output bus;

inserting into the receptacles a first set of removable modular units configured to measure direct current input at the respective input terminals;

measuring direct current at each of the plurality of input terminals using the first set of removable modular units;

analyzing the measurements made by the first set of removable modular units to identify a receptacle that is currently installed with a first removable modular unit without a direct current converter, and which receptacle, when installed with a second removable modular unit having a direct current converter, can use the direct current converter to improve energy production provided to the output bus; and

replacing, in the receptacle, the first removable modular unit with the second removable modular unit.

19. The method of claim 18, further comprising:

analyzing the measurements to identify a second slot that is currently installed with a third removable modular unit having a circuit to measure a direct current input from a corresponding input terminal; and

replacing, in the second slot, the third removable modular unit with a fourth removable modular unit that does not have a circuit to measure the direct current input from the corresponding input terminal.

20. The method of claim 19, wherein the slot with the first removable modular unit and the slot with the third removable modular unit are identified based on comparing the measurements with a target direct current range.