WO2013020250A1

WO2013020250A1 - Solar inverter

Info

Publication number: WO2013020250A1
Application number: PCT/CN2011/001330
Authority: WO
Inventors: John S. HARRISON; Zhenyi ZHENG
Original assignee: General Electric Company
Priority date: 2011-08-11
Filing date: 2011-08-11
Publication date: 2013-02-14

Abstract

The present application provides a solar inverter. The solar inverter may include an enclosure and an electrical component positioned within the enclosure. The enclosure may include a blast shield and a vent system positioned about the electrical component.

Description

SOLAR INVERTER

TECHNICAL FIELD

The present application and the resultant patent relate generally to solar power generation and conversion equipment and more particularly relate to a solar inverter with an enclosure having a blast shield and a vent system for blast containment and direction.

BACKGROUND OF THE INVENTION

A direct current power source such as a photovoltaic cell typically produces a low voltage at a high current. The power produced by such direct current power sources may be inconsistent and may vary with local operating and ambient conditions. Because many power applications require a relatively stable source of alternating current power, power conversion systems have been adapted to modify the power being supplied from a direct current power source such as a photovoltaic cell to alternating current for use with a utility grid and the like.

Existing power conversion equipment typically may be installed within an enclosure. The enclosure provides protection from dust particles and the like and also may provide thermal management. An enclosure for a utility grade solar inverter will have both a direct current connection point from the photovoltaic cells and an alternating current connection point leading to the utility grid. These connection points may be vulnerable to a fault event given that the connection points are generally positioned before current protection devices such as fuses or breakers. In the unlikely event that a short or the like is created at one of these connection points, a tremendous amount of energy could be released. Typical shielding provided by a known enclosure may not be sufficient to contain such forces.

There is therefore a desire for an improved enclosure for a solar inverter and similar types of power conversion equipment. Preferably such an enclosure can withstand and dissipate energies released by a fault event such as short, an arc fault, and the like so as to reduce the risk of harm to persons and other equipment positioned thereabout. SUMMARY OF THE INVENTION

The present application and the resultant patent thus provide a solar inverter. The solar inverter may include an enclosure and an electrical component positioned within the enclosure. The enclosure may include a blast shield and a vent system positioned about the electrical component.

The present application and the resultant patent further may provide a power conversion system. The power conversion system may include one or more solar array sections and a solar inverter in communication with the solar array sections. The solar inverter may include a DC to AC inverter positioned about a blast shield and a fan system.

The present application and the resultant patent may further provide a solar inverter. The solar inverter may include a blast zone, a DC to AC inverter positioned within the blast zone, a blast shield positioned about the DC to AC inverter, and a pressure relief vent in communication with an air plenum positioned about the DC to AC inverter.

These and other features and improvements of the present application and the resultant patent will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic view of a power conversion system for converting direct current power to alternating current power.

Fig. 2 is a side cross-sectional view of a solar inverter as may be described herein. DETAILED DESCRIPTION

Referring now to the drawings, in which like numerals reflect like elements throughout several views, Fig. 1 shows a conventional power conversion system 10 for converting direct current (DC) power to alternating current (AC) power. The DC to AC power conversion system 10 may include one or more solar array sections 15 as the source of the DC power. Any number of these solar array sections 15 may be used herein. The solar array sections 15 may be a linked collection of photovoltaic cells 20. The photovoltaic cells 20 convert solar energy into DC power via a photovoltaic effect. Any type of photovoltaic cells 20 may be used herein. Because the power produced by any individual photovoltaic cell 20 may be relatively low, a number of the photovoltaic cells 20 may be linked together in series and/or parallel to form the array sections 15 such that the power from the individual photovoltaic cells 20 may be combined. Any number of solar array sections 15 and photovoltaic cells 20 may be used herein in any configuration.

As described above, the DC power output from the photovoltaic cells 20 may be influenced by local conditions such as temperature and the condition of the cells 20. The power output of the photovoltaic cells 20 thus may be variable. Moreover, utility grids generally require AC -type power. The DC power output of the photovoltaic cells 20 thus must be converted to AC power. The photovoltaic cells 20 of the solar array sections 15 thus may be electrically coupled to a power converter 25. The power converter 25 converts the DC power from the solar array sections 15 to a reliable and stable source of AC power. The power converter 25 may include a DC to DC converter 30. The DC to DC converter 30 may be coupled to the solar array sections 15 so as to condition the DC power and make it more stable. The DC to DC converter 30 may include a switching type regulator so as to regulate the DC voltage using a form of pulse width modulation control and other types of devices. The DC to DC converter 30 also may include a power converter, or a step up converter, that may be operable to boost the DC power from a first voltage to a second voltage and the like. Other configurations may be used herein.

The power converter 25 further may include a DC to AC inverter 35. The DC to AC inverter 35 may convert the relatively stable DC power produced by the DC to DC converter 30 into AC power. For example, the DC to AC inverter 35 may provide AC power in the form of a 60 Hertz sinusoidal wave and the like. Other types of outputs and configurations may be used herein. The power converter 25 and the components thereof may be housed in an enclosure 40. The enclosure 40 may be largely air tight so as to eliminate ambient airflow and reduce associated filtering efforts. Interfacing the power converter 25 with a utility grid 45 also may involve an isolation transformer 50. The isolation transformer 50 largely isolates the solar array sections 15. Other components and other configurations may be used herein.

Fig. 2 shows an example of solar inverter 100 as may be described herein. The solar inverter 100 may be part of a power conversion system 105 as described above. The solar inverter 100 includes at least a DC to AC inverter 1 10 positioned within an enclosure 120. The DC to AC inverter 1 10 may be similar to that described above. Other types of components, such as the DC to DC converter 30 and the like, also may be positioned within the enclosure 120. The DC to DC converter 30 also may be positioned elsewhere such as in a closer relationship to the solar array sections 15.

The DC to AC inverter 1 10 may be positioned within a blast zone 130 of the enclosure 120. The enclosure 120 may have any number of inverters 1 10 and any number of blast zones 130. The blast zone 130 may be a blast resistant area enclosed by a blast shield 140. The blast shield 140 may be removable so as to provide access to the inverter 110 and other components. The blast shield 140 may be held in place by a number of fasteners 150 such as bolts or other types of fastening means. The blast shield 140 may be made from zinc hot dip steel, other types of high strength metals and alloys, and similar types of materials. The blast shield 140 may withstand a high loading force and a high pressure load (force/area). The blast shield 140 also may have a number of ribs 160 positioned thereon for reinforcement. The blast shield 140 may have any desired size, shape, or configuration. More than one blast shield 140 may be used about the blast zone 130.

A determination of whether the blast shield 140 can withstand the pressure developed by a fault event and the like may be determined by the follows formula:

P = 1 1.58(Iarc)/D^{0 9}

In this formula, the pressure P is determined in pounds per square foot, the arcing current Iarc is found in kilo-amps, and the distance D from the arc is found in feet. (See Ralph H. Lee, "Pressure Developed by Arcs," IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, Vol. 1A-23, July/August 1987). The overall size of the enclosure 120 and the blast zone 130 thus may be determined in context of the blast shield 140 and the given DC to AC inverter 110. Other types of parameters also may be considered herein.

The enclosure 120 may have a vent system 170 positioned about and in communication with the blast zone 130. The vent system 170 may include a one-way pressure relief vent 180 such as a pivotable metal plate 1850 or other type of vent structure. The pivotable metal plate 180 may be spring loaded or otherwise returnable. A significant amount of force may be required to cause the pressure relief vent 180 or other type of vent structure to open and/or to remain open. The pressure relief vent 180 or other type of vent structure also may be made from high strength metals, alloys, and the like. Other components and other configurations may be used herein.

The vent system 170 of the enclosure 120 may have air plenum 190 in communication with the pressure relief vent 180 or other vent structure of the blast zone 130. The air plenum 190 may lead to an exhaust exit 210 about a roof 220 of the enclosure 120 or otherwise. The air plenum 190 may have any desired size shape or configuration. A number of baffles also may be used herein. The exhaust exit 210 may be enclosed and/or positioned in a direction away for persons and other types of equipment.

In use, the enclosure 120 of the solar inverter 100 may accommodate a blast force 220 caused by the energies released from a fault event such as a short, arc event, and the like about the inverter 1 10. Although the blast shield 140 in and of itself may not be sufficient to accommodate such blast forces 220 without failure, the combination of the blast shield 140 and the vent system 170 can accommodate significantly higher forces. Specifically, the blast forces 220 may be contained by the blast shield 140, expand outwardly through the pressure relief vent 180 or other vent structure, the air plenum 190, and the exhaust exit 200 of the vent system 170, and may be dissipated in the atmosphere outside of the enclosure 120. The exhaust exit 200 may be on the roof 210 of the enclosure 120 or otherwise positioned. The exhaust exit 200 preferably may be positioned away from persons and/or other types of equipment. The vent system 170 thus directs the blast forces 220 away from the blast zone 130 and provides a safe path to the atmosphere. The use of the vent system 170 also may allow the blast shield 140 to be reduced in size or strength.

Although the enclosure 120 has been described in the context of a fault event caused by the inverter 110, the blast shield 140 and the vent system 170 of the enclosure 120 may accommodate the blast forces 220 from any type of electrical component 230. Multiple electrical components 230 also may be used herein.

It should be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.

Claims

WHAT IS CLAIMED IS:

1. A solar inverter, comprising: an enclosure; and an electrical component positioned within the enclosure; the enclosure comprising a blast shield and a vent system positioned about the electrical component.

2. The solar inverter of claim 1, wherein the enclosure comprises a blast zone and wherein the electrical component is positioned within the blast zone.

3. The solar inverter of claim 2, wherein the blast shield encloses the blast zone.

4. The solar inverter of claim 2, wherein the enclosure comprises a plurality of blast zones.

5. The solar inverter of claim 1, wherein the enclosure comprises a plurality of fasteners to secure the blast shield.

6. The solar inverter of claim 1 , wherein the blast shield comprises one or more ribs thereon.

7. The solar inverter of claim 1, wherein the vent system comprises a pressure relief vent.

8. The solar inverter of claim 7, wherein the pressure relief vent comprises a pivotable plate.

9. The solar inverter of claim 1, wherein the vent system comprises an air plenum.

10. The solar inverter of claim 1, wherein the vent system comprises an exhaust exit.

1 1. The solar inverter of claim 1 , wherein the electrical component comprises a DC to AC inverter.

12. The solar inverter of claim 1 1, further comprising one or more solar array sections in communication with the DC to AC inverter.

13. The solar inverter of claim 12, wherein the one or more solar array sections comprise a plurality of photovoltaic cells.

14. The solar inverter of claim 1 1, further comprising a utility grid in communication with the DC to AC inverter.

15. The solar inverter of claim 1, wherein the electrical component comprises a DC to DC converter.

16. A power conversion system, comprising: one or more solar array sections; and a solar inverter in communication with the one or more solar array sections; the solar inverter comprising a DC to AC inverter positioned about a blast shield and a fan system.

17. The power conversion system of claim 16, wherein the solar inverter comprises a blast zone and wherein the DC to AC inverter is positioned within the blast zone.

18. The power conversion system of claim 16, wherein the fan system comprises a pressure relief vent and an air plenum.

19. The power conversion system of claim 16, further comprising a utility grid in communication with the solar inverter.

20. A solar inverter, comprising: a blast zone; a DC to AC inverter positioned within the blast zone; a blast shield positioned about the DC to AC inverter; and a pressure relief vent in communication with an air plenum positioned about the DC to AC inverter.