Photovoltaic DC/DC micro-converter

• US 8,106,537 B2
• Filed: 07/01/2009
• Issued: 01/31/2012
• Est. Priority Date: 07/01/2008
• Status: Active Grant

• Current Assignee: Perfect Galaxy International Limited
• Original Assignee: Satcon Technology Corporation
• Inventors: Casey, Leo Francis, Prestero, Mark George, Rajda, Janos
• Primary Examiner(s): PALADINI, ALBERT WILLIAM
• Application Number:
  US12/495,840
• Publication Number:
  US 20100001587A1
• Time in Patent Office: 944 Days
• Field of Search: 307/82, 136/244, 136/291, 136/252, 323/906, 363/95
• US Class Current: 307/82
• 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 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources maximum power point systems in particular G05F1/67
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02S 40/32 comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A photo-voltaic (PV) power generating system and a control system for PV array string-level control and PV modules serially-connected into strings of PV modules. The system includes plural parallel strings of serially-connected power-generating photovoltaic modules that form a PV array, DC/DC micro-converters that are coupled to a DC voltage buss and to the output of a corresponding photovoltaic module or to the output of a string of photovoltaic modules; a gating or central inverter; and a control system. The control system is structured and arranged to control and manage each string of photovoltaic modules, to ensure that power delivered by the photovoltaic power generating system is not affected by photovoltaic modules or strings of photovoltaic modules that are not operating at maximum power transfer efficiency.

Claims

1. A photovoltaic power generating system comprising:

a power-generating portion including plural parallel strings of power-generating photovoltaic modules, the power-generating photovoltaic modules being coupled in series in each of the parallel strings, the strings forming an array, each of the strings and each of the modules having an output;

a plurality of DC/DC micro-converters, each of said plurality of micro-converters being coupled to a regulated DC voltage buss and to the output of a discrete, corresponding photovoltaic module or to the output of a string of photovoltaic modules;

an inverter that is coupled to the regulated DC voltage buss and to a load; and

a control system that is structured and arranged to control each string of photovoltaic modules, to ensure that power delivered by the photovoltaic power-generating system is not affected by photovoltaic modules or serial strings of photovoltaic modules that are not operating at maximum power efficiency.

2. The system as recited in claim 1, wherein each of the plurality of DC/DC micro-converters is adapted to communicate performance data and operating parameters selected from the group consisting of terminal current level, terminal voltage level, power parameters, string ground faults, and thermal operating parameters to a controller.

3. The system as recited in claim 2, wherein the controller is adapted to provide fine-grained data on performance of discrete photovoltaic modules, strings of photovoltaic modules or any portion of the array of power-generating photovoltaic modules.

4. The system as recited in claim 2, wherein communication to the controller is via a wireless connection or a powerline carrier connection.

5. The system as recited in claim 2, wherein the controller is a control unit corresponding to the inverter or a portion of the control system.

6. The system as recited in claim 1, wherein each of the plurality of DC/DC micro-converters is disposed in a string combiner.

7. The system as recited in claim 1, wherein the inverter includes a control unit and at least one energy storage device.

8. The system as recited in claim 1, wherein the control system is adapted to adjust gating signals to each of the micro-converters to maintain a desired output voltage.

9. The system as recited in claim 1, wherein the control system is adapted to adjust gating signals to each of the micro-converters to boost output of an affected, low-output photovoltaic module or string of affected, low-output photovoltaic modules, to within a capability range of the DC/DC micro-converter or to isolate or remove an affected, low-output photovoltaic module or string of affected, low-output photovoltaic modules, to prevent degradation of the array.

10. The system as recited in claim 1, wherein the inverter includes a control unit that is adapted to:

receive data from each of the plurality of micro-controllers about each of said plurality of micro-controllers and about their corresponding photovoltaic module;

control which of the corresponding photovoltaic modules and micro-controllers provide power to the voltage buss; and

control an amount of power from specific photovoltaic modules and their micro-controllers individually.

19. The system as recited in claim 1, wherein the control system is coupled to a Web-base or a non-Web-based monitoring and management system for remotely monitoring and controlling the plurality of micro-converters.

11. A control system for a photovoltaic power generating system that includes a power-generating portion including plural serial strings of power-generating photovoltaic modules that form an array, each of the serial strings and each of the modules having an output, a plurality of DC/DC micro-converters, each of said plurality of micro-converters being coupled to a voltage buss and to the output of a discrete, corresponding photovoltaic module or to the output of a serial string of photovoltaic modules, an inverter that is coupled to the voltage buss and that is structured and arranged to provide power to a grid or to a DC load, the control system being structured and arranged to control each serial string of photovoltaic modules, to ensure that power delivered by the photovoltaic power generating system is not affected by photovoltaic modules or serial strings of photovoltaic modules that are not operating at maximum power efficiency.

12. The control system as recited in claim 11, wherein the control system is adapted to receive performance data and operating parameters selected from the group consisting of terminal current level, terminal voltage level, power parameters, and thermal operating parameters from each of the plurality of DC/DC micro-converters.

13. The control system as recited in claim 12, wherein the control system is adapted to provide fine-grained data on performance of discrete photovoltaic modules, serial strings of photovoltaic modules or any portion of the array of power-generating photovoltaic modules.

14. The control system as recited in claim 12, wherein communication between the control system and each of the plurality of DC/DC micro-converters is via a wireless connection or a powerline carrier connection.

15. The control system as recited in claim 11 further adapted to adjust gating signals to each of the micro-converters to maintain a desired output voltage.

16. The control system as recited in claim 11 further adapted to adjust gating signals to each of the micro-converters to isolate or remove an affected, low-output photovoltaic module or string of affected, low-output photovoltaic modules, to prevent degradation of the array.

17. The control system as recited in claim 11 further adapted to:

receive data from each of the plurality of micro-controllers about each of said plurality of micro-controllers'"'"' corresponding photovoltaic module; and

control which of the corresponding photovoltaic modules provide power to the voltage buss.

18. The control system as recited in claim 11, wherein the control system is coupled to a Web-base or a non-Web-based monitoring and management system for remotely monitoring and controlling the plurality of micro-converters.