Solar Photovoltaic Systems

• US 20120161528A1
• Filed: 09/23/2011
• Published: 06/28/2012
• Est. Priority Date: 01/18/2011
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: SolarCity Corporation (Tesla Inc.)
• Inventors: Amaratunga, Gehan Anil Joseph, Mumtaz, Asim, Engle, Paul Randal Jr., Matthew, Andrew John
• Granted Patent: US 9,276,409 B2
• Time in Patent Office: Days
• US Class Current: 307/82
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/48 Controlling the sharing of the in-phase component
• CPC Class Codes: H02M 7/44 by static converters
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

Improved techniques for photovoltaic power generation are described. Inverter failure is can be a significant problem in solar photovoltaic systems as it can lead to loss of opportunity to harvest energy. A solar photovoltaic (PV) power generation system is described comprising solar PV panels and power conditioning units. A dc power distribution bus is coupled to the solar PV panels and the power conditioning units to switchably share dc power from the solar PV panels between the power conditioning units. Power distribution controllers detect a faulty power conditioning unit and reroute power from a solar PV panel coupled to the faulty power conditioning unit to other power conditioning units via the dc distribution bus.

Claims

1. A solar photovoltaic (PV) power generation system comprising:

a plurality of solar PV panels each having a dc output for delivering dc power;

a plurality of power conditioning units each having a dc power input coupled to said dc output of said respective one of said plurality of solar PV panels and an ac mains power supply output for delivering an ac mains supply;

a dc power distribution bus coupled to said plurality of solar PV panels and said plurality of power conditioning units to share dc power from said plurality of solar PV panels between said plurality of power conditioning units; and

a plurality of power distribution controllers for controlling distribution of said dc power;

wherein each of said plurality of power conditioning units is coupled to a respective one of one of said plurality of solar PV panels;

wherein each of said plurality of power conditioning units is further coupled to a respective one of a plurality of power distribution controllers; and

wherein each of said plurality of power distribution controllers comprises a fault detector to detect a faulty one or more of said plurality of power conditioning units, and responsive to said detecting a faulty one or more of said plurality of power conditioning units to distribute said dc power from said dc output of said solar PV panel coupled to said faulty one or more of said plurality of power conditioning units to others of said plurality of power conditioning units via said dc distribution bus.

2. A solar PV power generation system as claimed in claim 1,

wherein a first of said plurality of solar PV panels is coupled to a first of said plurality of power conditioning units, and wherein said first of said power conditioning units is coupled to a first of said plurality of power distribution controllers;

wherein said first of said plurality of solar PV panels is coupled to said dc distribution bus via a first switched connection, and

wherein said first of said plurality of power distribution controllers is operable to close said first switched connection to couple said first of said plurality of solar PV panels to said dc distribution bus responsive to said fault detector in a first of said plurality of power distribution controllers detecting a faulty first of said plurality of power conditioning units.

3. A solar PV power generation system as claimed in claim 1, wherein a first of said plurality of solar PV panels is coupled to a first of said plurality of power conditioning units, and wherein said first of said power conditioning units is coupled to a first of said plurality of power distribution controllers;

and wherein a first of said plurality of solar PV panels is coupled to said dc distribution bus via a diode.

4. A solar PV power generation system as claimed in claim 2, wherein one or more others of said plurality of power conditioning units are coupled to said dc distribution bus via a respective second switched connection;

and wherein one or more others of said plurality of power distribution controllers are operable to close said respective second switched connection to couple said dc distribution bus to said respective one or more others of said plurality of power conditioning units responsive to sensing a fault in said first of said plurality of power conditioning units.

5. A solar PV power generation system as claimed in claim 4, wherein said sensing comprises detecting a signal on said dc distribution bus.

6. A solar PV power generation system as claimed in claim 5, wherein said sensing comprises sensing a dc voltage on said dc distribution bus.

7. A solar PV power generation system as claimed in claim 4, wherein said first of said plurality of power distribution controllers comprises a communications output to transmit fault data signalling a faulty first of said plurality of power conditioning units, and wherein said sensing comprises detecting said fault data.

8. A solar PV power generation system as claimed in claim 7, wherein said transmitting comprises broadcasting said fault data to said one or more others of said plurality of power distribution controllers.

9. A solar PV power generation system as claimed in claim 8, wherein said transmitting comprises first transmitting said fault data to a central controller, and transmitting said fault data to said one or more others of said plurality of power distribution controllers using said central controller.

10. A solar PV power generation system as claimed in claim 8, wherein said plurality of power distribution controllers each comprises an RF transceiver and said transmitting comprises wirelessly transmitting said fault data.

11. A solar PV power generation system as claimed in claim 2, wherein said first of said plurality of solar PV panels is coupled to said first of said plurality of power conditioning units via a third switched connection, and wherein said first of said power distribution controllers is operable to open said third switched connection to disconnect said first of said plurality of solar PV panels from said first of said plurality of power conditioning units responsive to said fault detector in said first of said plurality of power distribution controllers detecting said faulty first of said plurality of power conditioning units.

12. A solar PV power generation system as claimed in claim 11, wherein said fault detector in said first of said plurality of power conditioning units comprises a short-circuit detector.

13. A fail-safe solar PV power conversion unit for use in a solar PV power generation system, the fail-safe solar PV power conversion unit comprising:

a dc input for receiving dc power from a solar PV panel;

a power conditioning unit coupled to said dc input to receive said dc power and ac mains power supply output for delivering an ac mains supply;

a dc power distribution bus coupled to said dc input and to said power conditioning unit and to a dc power distribution port, said dc power distribution port, when coupled to others of said fail-safe solar PV power conversion units, being operable to share dc power from said dc power distribution bus; and

a power distribution controller coupled to said power conditioning unit for controlling distribution of said dc power;

wherein said power distribution controller comprises a fault detector to detect a fault in said power conditioning unit and responsive to said fault detector detecting a fault to distribute said dc power from said dc input to said dc distribution port via said dc power distribution bus.

14. A fault tolerant solar PV power generation system comprising a plurality of fail-safe solar PV power conversion units as claimed in claim 13, wherein each of said plurality of fail-safe solar PV power conversion units are coupled to others of said plurality of fail-safe solar PV power conversion units via said dc power distribution bus.

15. A fault tolerant solar PV power generation system comprising:

a first solar PV panel having a dc output for delivering power;

a first power conditioning unit (PCU) having a dc power input coupled to said dc output of said first solar PV panel and an ac mains power supply output for delivering an ac mains supply, wherein said dc power input of said first power conditioning unit is coupled to said dc output of said first solar PV panel via a first PCU switch;

a first power distribution controller (PDC) for controlling distribution of said dc power from said first solar PV panel, wherein said first PDC is coupled to said dc output of said first solar PV panel;

a second solar PV panel having a dc output for delivering power;

a second PCU having a dc power input coupled to said dc output of said second solar PV panel and an ac mains power supply output for delivering an ac mains supply, wherein said dc power input of said second power conditioning unit is coupled to said dc output of said first solar PV panel via a second PCU switch;

a second PDC for controlling distribution of said dc power from said second solar PV panel, wherein said second PDC is coupled to said dc output of said second solar PV panel;

a dc power distribution bus (PDB) coupled to said first and said second solar PV panels and said first and said second PCUs to share dc power from said first and said second solar PV panels between said first and said second PCUs, wherein said dc PDB is coupled to said first solar PV panel and said first PCU via a first PDB switch and wherein said dc PDB is coupled to said second solar PV panel and said second PCU via a second PDB switch;

wherein said first PDC comprises a fault detector to detect a fault in said first PCU, and responsive to said detecting a fault said first PDC is configured to close said first PDB switch to connect said second solar PV panel to said dc PDB; and

wherein said second PDC comprises a dc sense circuit to detect a dc voltage on said dc PDB, and responsive to said detecting a dc voltage on said dc PDB said second PDC is configured to close said second PDB switch to connect said dc PDB to said second PCU.

16. A fault tolerant solar PV power generation system as claimed in claim 15, wherein said fault detector comprises a short circuit detector to detect a short circuit in said first PCU, and responsive to said detecting a short circuit said first PDC is configured to open said first PCU switch to disconnect said dc power output of said first solar PV panel from said dc input of said first PCU.

17-18. -18. (canceled)