PHOTOVOLTAIC POWER GENERATING DEVICE, AND CONTROLLING METHOD

• US 20120048325A1
• Filed: 08/24/2010
• Published: 03/01/2012
• Est. Priority Date: 08/24/2010
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: MATSUO, Takahisa, NISHIKAWA, Shuhei, SEKINE, Tsuyoshi
• Granted Patent: US 8,461,716 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: H02H 3/305 involving current comparison
• CPC Class Codes: H02H 7/20 for electronic equipment for converters H02H7/10; for electric measuring instruments G01R1/36; for dc voltage or current semiconductor regulators G05F1/569; for amplifiers H03F1/52; for electronic switching circuits H03K17/08
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A photovoltaic power generating device comprising a current collecting box side detector for detecting a ground fault in each of the photovoltaic strings, a switch disposed in correspondence to each of the photovoltaic strings and interposed between the photovoltaic string and a connecting cable, a current collecting box including a control unit providing an on/off control of the switch according to the detection result from the detector, a detector for detecting a ground fault in a connecting cable between the current collecting box and the power conditioner, a switch interposed between the connecting cable and the inverter, and a power conditioner having a control unit providing an on/off control of the switch according to the detection result from the detector.

Claims

1. A photovoltaic power generating device, comprising:

a plurality of photovoltaic strings;

a current collecting box serving to collect electric power from the plural photovoltaic strings; and

a power conditioner supplied with the electric power from the plural current collecting boxes, and having an inverter for converting the electric power into the alternating current power,

wherein the current collecting box includes;

a current collecting box side detector for detecting a ground fault in each of the photovoltaic strings;

a current collecting box side switch provided in correspondence to each of the photovoltaic strings and interposed between the photovoltaic string and a connecting cable; and

a current collecting box side control unit applying an on/off control to the switch according to a detection result supplied from the detector, and

wherein the power conditioner includes;

an inverter side detector for detecting a ground fault in a connecting cable between the current collecting box and the power conditioner;

an inverter side switch interposed between the connecting cable and the inverter; and

a power conditioner side control unit applying an on/off control to the inverter side switch according to a detection result supplied from the inverter side detector.

2. The photovoltaic power generating device according to claim 1, wherein the line from the current collecting box to the power conditioner is longer than the line from the photovoltaic string to the current collecting box.

3. The photovoltaic power generating device according to claim 1, wherein the current collecting box side detector has different detection sensitivity from the inverter side detector.

4. The photovoltaic power generating device according to claim 1, wherein the detection sensitivity of the current collecting box side detector is higher than that of the inverter side detector.

5. The photovoltaic power generating device according to claim 1, wherein the number of the photovoltaic strings is the largest and the number decreases in the descending order of the current collecting box and the power conditioner.

6. The photovoltaic power generating device according to claim 1, wherein a main control unit of the photovoltaic power generating device is connected with the current collecting box and the power conditioner via a communication path, and information concerning the occurrence of a ground fault is sent to the main control unit.

7. A controlling method for a photovoltaic power generating device that comprises:

a plurality of photovoltaic strings;

a current collecting box serving to collect electric power from the plural photovoltaic strings; and

a power conditioner supplied with the electric power from the plural current collecting boxes, and having an inverter for converting the electric power into the alternating current power, wherein the current collecting box includes;

a current collecting box side detector for detecting a ground fault in each of the photovoltaic strings;

a switch provided in correspondence to each of the photovoltaic strings and interposed between the photovoltaic string and a connecting cable; and

a current collecting box side control unit applying an on/off control to the switch according to a detection result supplied from the detector, and the power conditioner includes;

an inverter side detector for detecting a ground fault in a connecting cable between the current collecting box and the power conditioner;

an inverter side switch interposed between the connecting cable and the inverter; and

a power conditioner side control unit applying an on/off control to the inverter side switch according to a detection result supplied from the inverter side detector, the method comprising;

upon detection of a ground fault by the current collecting box side detector, switching off the switch of the corresponding photovoltaic string so as to cut off an output from the corresponding photovoltaic string, and

upon detection of a ground fault by the inverter side detector, switching off the inverter side switch so as to break connection between the connecting cable and the inverter.

8. The controlling method for a photovoltaic power generating device according to claim 7, wherein the device further comprises a communication path for connecting the main control unit of the photovoltaic power generating device with the current collecting box and the power conditioner,

the method further comprising upon detection of a ground fault by the current collecting box side detector or the inverter side detector, sending information concerning the occurrence of a ground fault to the main control unit.