Solar power generation apparatus and control method therefor

• US 20010023703A1
• Filed: 02/26/2001
• Published: 09/27/2001
• Est. Priority Date: 02/29/2000
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Kondo, Hiroshi, Takehara, Nobuyoshi, Manabe, Naoki
• Granted Patent: US 6,593,520 B2
• Time in Patent Office: Days
• US Class Current: 136/244
• 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: 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: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10S 136/291 Applications
• CPC Class Codes: Y10S 136/293 Circuits
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

When a ground fault occurs in some solar battery string, this solar battery string may be disconnected and operation of a solar power generation system may be continued. If the open-circuit voltage of the solar battery string is high, a safety problem arises. If the open-circuit voltage is decreased, the conversion efficiency decreases. Therefore, an intermediate switch is provided midway along the solar battery string. When a ground fault occurs, this solar battery string where the ground fault has occurred is divided into substrings.

Claims

1. A solar power generation apparatus comprising:

a solar battery string formed by a plurality of series-connected solar panels;

a detector for outputting an abnormality detection signal upon detection of a ground fault in the solar battery string; and

at least one switch provided midway along the solar battery string and shifted to an open state by the abnormality detection signal.

2. The apparatus according to

claim 1

, wherein when plural switches are provided midway along the solar battery string, the plural switches can be opened/closed simultaneously.

3. The apparatus according to

claim 1

, wherein the detector and the at least one switch are housed in a collector box separate from the solar battery string.

4. The apparatus according to

claim 1

, further comprising an alarm for producing an alarm when the detector outputs an abnormality detection signal.

5. A solar power generation apparatus comprising:

a plurality of solar battery strings each formed by a plurality of series-connected solar panels, wherein the plurality of solar battery strings are parallel connected;

a plurality of detectors for detecting a ground fault in units of the plurality of solar battery strings, wherein the detectors output an abnormality detection signal upon detection of a ground fault; and

at least one first switch provided midway along each solar battery string, wherein the first switch is shifted to an open state by the abnormality detection signal.

6. The apparatus according to

claim 5

, further comprising a second switch for disconnecting one of the solar battery strings from remaining ones, wherein the second switch is shifted to an open state by the abnormality detection signal.

7. The apparatus according to

claim 6

, further comprising a delay unit for delaying the abnormality detection signal by a predetermined period of time, wherein the abnormality detection signal is supplied to the second switch directly and to the first switches through the delay unit.

8. The apparatus according to

claim 5

, wherein the plurality of detectors and the first switch are housed in a collector box separate from the solar battery strings.

9. The apparatus according to

claim 5

, wherein when plural first switches are provided midway along the each solar battery string, the first switches can be opened/closed simultaneously.

10. The apparatus according to

claim 5

, further comprising an alarm for producing an alarm when the detectors output an abnormality detection signal.

11. A control method of a solar power generation apparatus having a solar battery string formed by a plurality of series-connected solar panels, and at least one switch provided midway along the solar battery string and shifted to an open state by an abnormality detection signal, comprising the step of shifting the at least one switch provided midway along the solar battery string where the ground fault has occurred to an open state when a ground fault in the solar battery string is detected.

12. A control method of a solar power generation apparatus which has a plurality of solar battery strings each formed by a plurality of series-connected solar panels, wherein the plurality of solar battery strings are parallel connected, and at least one first switch provided midway along each solar battery string, comprising the steps of:

detecting a ground fault in a unit of the plurality of solar battery strings; and

shifting the first switch, which is provided the solar battery string detected the ground fault, to an open state.

13. The method according to

claim 12

, further comprising the step of, upon detection of the ground fault of the solar battery strings, shifting a second switch, serving to disconnect that one of the solar battery strings where the ground fault has occurred from remaining ones, to an open state.

14. The method according to

claim 13

, where upon detection of the ground fault in one the solar battery strings, the second switch is shifted to an open state immediately, and the first switches are shifted to an open state with a lapse of a predetermined period of time.