Photovoltaic power generation systems and methods of controlling photovoltaic power generation systems

• US 7,161,082 B2
• Filed: 09/15/2003
• Issued: 01/09/2007
• Est. Priority Date: 07/10/2000
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Takabayashi, Akiharu, Mori, Masahiro, Matsushita, Masaaki, Lim, Chinchou, Mukai, Takaaki, Shiomi, Ayako
• Primary Examiner(s): Olsen; Kaj K.
• Application Number:
  US10/661,673
• Publication Number:
  US 20040056768A1
• Time in Patent Office: 1,212 Days
• Field of Search: 136/290, 136/293, 136/244, 323/906, 323/221, 363/50, 361/115, 361/94, 361/93.1, 361/88, 361/89
• US Class Current: 136/244
• CPC Class Codes: G08B 13/128 the housing being an electronic circuit unit, e.g. memory or CPU chip protecting computer components in secure or tamper resistant housings G06F21/86; protecting computer input devices, e.g. keyboards G06F21/83
• 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 31/048 Encapsulation of modules
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10S 136/29 Testing, calibrating, treating, e.g. aging

Abstract

There are provided a restricted area including an area in which solar cell modules are installed, a preventer for preventing intrusion of an intruder into the restricted area, and a detector capable of detecting the intrusion of the intruder into the restricted area, and a predetermined electric shock preventer is activated by a signal outputted from the detector upon detection of the intruder to prevent the intruder from receiving an electric shock.

Claims

1. A method of controlling a photovoltaic power generation system including a solar cell string comprised of a plurality of connected solar cell modules, a plurality of sensors provided around the solar cell string, and a switch for establishing a short circuit between output terminals of the solar cell string, based on output signals from the plurality of sensors, the method comprising:

a first step of measuring the output signals from the plurality of sensors;

a second step of normalizing values of the output signals;

a third step of comparing the normalized output signal values to a reference value S;

a fourth step of calculating a comparison calculated value D, which is defined below, when at least one of a plurality of normalized output signal values Ax is larger than the reference value S,

the comparison calculated value D=(a minimum of the plurality of normalized output signal values Ax)/(a maximum of the plurality of normalized output signal values Ax); and

a fifth step of establishing the short circuit between the output terminals by the switch when the comparison calculated value D is smaller than a comparison reference value D0.

2. The method according to claim 1, wherein an alarm is issued before the short circuit between the output terminals is established.

3. The method according to claim 2, wherein when an output period of the alarm is longer than a time T0, the short circuit between the output terminals is established by the switch.

4. The method according to claim 1, wherein the plurality of sensors is comprised of solar cells.

5. A method of controlling a photovoltaic power generation system including a plurality of solar cell strings connected in parallel, each solar cell string being comprised of a plurality of connected solar cell modules, and each solar cell string having a plurality of sensors provided around the solar cell string and a switch for establishing a short circuit between output terminals of the solar cell swing, the method comprising:

(1) carrying out for each of the plurality of solar cell strings,

a first step of measuring output signals from the plurality of sensors,

a second step of normalizing values of the output signals,

a third step of comparing the normalized output signal values to a reference value S, and

a fourth step of calculating a comparison calculated value Dy, which is defined below, when at least one of a plurality of normalized output signal values Ax is larger than the reference value S,

the comparison calculated value Dy=(a minimum of the plurality of normalized output signal values Ax)/(a maximum of the plurality of normalized output signal values Ax); and

(2) carrying out a fifth step when at least one of the comparison calculated values Dy of the plurality of solar coil strings is smaller than a comparison reference value D0,

the fifth step being a step of establishing a short circuit between output terminals of a solar cell string corresponding to the comparison calculated value Dy smaller than the comparison reference value D0, by the switch.

6. The method according to claim 5, wherein before the short circuit is established between the output terminals of the solar cell string corresponding to the comparison calculated value Dy smaller than the comparison reference value D0, an alarm is issued for the solar cell string.

7. The method according to claim 6, wherein when an output period of the alarm is longer than a time T0, the short circuit is established between the output terminals of the solar cell string corresponding to the comparison calculated value Dy smaller than the comparison reference value D0.

8. The method according to claim 5, wherein the plurality of sensors is comprised of solar veils.