JP2001238466A - System interconnection inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a system interconnection inverter device that prevents a switching element for composing an inverter part from being damaged thermally, when abnormality in temperature occurs inside a device, quickly detects failure, such as improper operation and breakdown caused by abnormality in temperature in other heat generation parts for composing the inverter part, and provides higher safety. SOLUTION: This system interconnection inverter device is equipped with an inverter part 3, that converts DC power that is supplied from a solar cell or the like to AC power, a switching means that opens and closes the connection between the output of the inverter part 3 and a system power supply, a first temperature-sensing part that senses the temperature of a switching element for constituting the inverter part 3, and a second temperature-sensing part that senses the temperature of other heat generation parts for composing the inverter part 3, and secures safety and reliability of the device according to information on the temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device for connecting DC power from a solar cell, a fuel cell or the like to a system power supply and supplying it as AC power.

[0002]

2. Description of the Related Art An example of a conventionally used system interconnection inverter device will be described with reference to FIG. A grid interconnection inverter device 11 for converting a DC power supplied from a solar cell 12 into an AC power and injecting the AC power into a system power supply 13; a control circuit unit 15 for controlling the operation of the inverter unit 14; And a temperature detecting section 16 for detecting the temperature of the switching element constituting the inverter section 14. The DC voltage supplied from the solar cell 12 is changed by the operation of the inverter unit 14 to the system power supply 1.
3 and controls the output current to be a sine wave by turning on / off a full-bridge switching element built in the inverter unit 14, and injecting this AC power into the system power supply 13. are doing.

[0003]

When a temperature abnormality occurs in the grid-connected inverter device 11 having the above configuration, the temperature is detected by a temperature detecting section 16 provided near the switching element in order to prevent the switching element from being destroyed. Detect
Generally, a function of stopping the oscillation of the switching element and restoring the operation if the temperature becomes lower than the abnormal temperature after a lapse of a predetermined time (about 30 minutes) is generally provided.

However, stopping the output of the inverter device due to abnormal temperature gives the user a disadvantage due to no power generation during that time. In addition, the components constituting the inverter device include choke coils other than switching elements. However, there is a problem that the conventional configuration cannot cope with a defect such as quality deterioration due to the heat generation.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional configuration. When an abnormal temperature occurs in the inverter device, the temperature of the switching element constituting the inverter section is reduced. And a second temperature detecting unit for detecting the temperature of the other heat-generating components constituting the inverter unit are provided in the system interconnection inverter device.

Accordingly, when a temperature abnormality occurs in the device, the output of the inverter unit is controlled to prevent thermal destruction of the switching element constituting the inverter unit, and the temperature of other heat generating components constituting the inverter unit is also reduced. An object of the present invention is to provide a system interconnection inverter device that detects a defect such as quality deterioration caused by an abnormality quickly and has higher safety and reliability.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is an inverter for converting DC power supplied from a solar cell or the like into AC power, a relay for opening and closing the connection between the output of the inverter and a system power supply, and the like. Opening / closing means, a control circuit section for controlling the operation of the inverter section, a first temperature detection section for detecting the temperature of a switching element constituting the inverter section, and other heating components constituting the inverter section. A second temperature detecting unit for detecting a temperature is provided in the system interconnection inverter device, and the output of the inverter unit is controlled based on the temperature information.

According to a second aspect of the present invention, when one of the first temperature detecting section and the second temperature detecting section continuously detects a temperature equal to or higher than the temperature reduction detection level for a predetermined time or longer, This is configured to limit the output of the unit.

According to a third aspect of the present invention, when both the first temperature detecting section and the second temperature detecting section continuously detect a temperature lower than the temperature reduction release level for a certain period of time, the inverter section detects the temperature. The output is restored.

According to a fourth aspect of the present invention, when one of the first temperature detecting unit and the second temperature detecting unit continuously detects a temperature equal to or higher than the temperature abnormality detection level for a predetermined time or more, the inverter is activated. The output of the section is stopped and the opening / closing means is operated in the open state.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a circuit block diagram showing a configuration of the first invention. Grid-connected inverter device 1
Is an inverter unit 3 for converting DC power supplied from the solar cell 2 into AC power, and switching means 5 such as a relay for opening and closing the connection between the output of the inverter unit 3 and the system power supply 4.
And a control circuit unit 6 for controlling the operation of the inverter unit 3.
A first temperature detecting unit 7 for detecting the temperature of the switching element constituting the inverter unit 3 and a second temperature detecting unit 8 for detecting the temperature of other heat generating components constituting the inverter unit 3. The temperature control section controls the output of the inverter section based on the temperature information. By this action, the temperature rise inside the device can be reliably detected by the two temperature detecting sections and the temperature rise can be suppressed, so that it is possible to provide a more reliable and safer grid-connected inverter device.

(Embodiment 2) In the second invention, the first temperature detecting section 7 and the second temperature detecting section 8 shown in FIG. Having a temperature reduction detection level of this device when any one of them first reaches or exceeds the temperature point,
The output of the inverter unit 3 is limited. That is, at the elapsed time t1, the temperature of the second temperature detection unit has not reached the temperature reduction detection level (A2), but the temperature of the first temperature detection unit has reached the temperature reduction detection level (A1). Therefore, control is performed to limit the output of the inverter unit to a predetermined level (see FIG. 2).

By this action, the temperature rise in the device is immediately detected, and the output is limited from a maximum level to a predetermined level at which the temperature rise can be suppressed as much as possible. Since it is possible to protect against quality deterioration due to the rise, it is possible to provide a more reliable system interconnection inverter device without giving a disadvantage to a user. Here, it is determined that the detection level has been reached only when the temperature equal to or higher than the temperature reduction detection level is continuously detected for a predetermined time or more, in order to prevent erroneous detection due to noise or the like.

(Embodiment 3) In the third aspect of the present invention, the first temperature detecting section 7 and the second temperature detecting section 8 shown in FIG. When both of the temperatures fall below that temperature point, the temperature reduction release level of the device is determined, and the output of the inverter unit 3 is returned to the original maximum output. That is, at the time point of the elapsed time t2, the temperature of the first temperature detection unit has reached the temperature reduction release level (B1), but the temperature of the second temperature detection unit has still reached the temperature reduction release level (B2). Therefore, the control is performed so that the output of the inverter unit is returned to the original maximum level after waiting until the elapsed time t3 when both of the two temperature detection units reach the temperature reduction release level or lower (see FIG. 3).

With this function, it is possible to more reliably detect that the internal temperature of the device has returned to normal, so that thermal stress on the inverter components can be reduced and a more reliable grid-connected inverter device can be provided. It is. Here, the reason that the normal recovery is determined only when the temperature equal to or lower than the temperature reduction release level is continuously detected for a predetermined time or more is as follows.
This is to prevent erroneous detection due to noise or the like.

(Embodiment 4) In the fourth aspect of the present invention, the first temperature detecting section 7 and the second temperature detecting section 8 shown in FIG. Having a temperature abnormality detection level of this device when any one of them first becomes equal to or higher than the temperature point,
The output of the inverter unit is stopped, and the opening / closing means is operated in the open state. That is, the elapsed time t4
In, the temperature of the second temperature detection unit has not reached the temperature abnormality detection level (C2), but the output of the inverter unit is stopped because the temperature of the first temperature detection unit has reached the temperature abnormality detection level (C1). And the opening / closing means is controlled to be in the open state (see FIG. 4).

By this function, an abnormal temperature rise in the device is detected to protect the inverter components from destruction due to thermal runaway, etc., and a more secure system interconnection inverter device can be provided. Here, the reason why the abnormality is determined only when the temperature equal to or higher than the temperature abnormality detection level is continuously detected for a certain period of time or more is to prevent erroneous detection due to noise or the like.

Here, A used in the description of Examples 2 to 4,
The setting values of B and C are C>A> B in descending order, and
It is desirable to provide a temperature difference of about 10 degrees each.

In the second embodiment, the set value of the level at which the output of the inverter section is limited differs depending on the specific configuration of the system interconnection inverter device.
Needless to say, it also includes zero output (inverter stopped).

[0021]

As described above, according to the first aspect of the present invention, since the temperature rise inside the device can be reliably detected by the two temperature detecting units, the grid-connected inverter having higher reliability and safety can be obtained. An apparatus can be provided.

According to the second aspect of the present invention, it is possible to protect the inverter components from quality deterioration due to the temperature rise while quickly detecting the temperature rise in the device and obtaining an appropriate output. It is possible to provide a more reliable system interconnection inverter device without giving a disadvantage to a user.

Further, according to the third aspect of the present invention, it is possible to more reliably detect that the temperature in the device has returned to normal, so that thermal stress on the inverter components can be reduced, and a more reliable system can be obtained. An interconnection inverter device can be provided.

According to the fourth aspect of the present invention, an abnormally high temperature in the apparatus is detected to protect inverter components from destruction due to thermal runaway, etc., and a more secure grid-connected inverter apparatus is provided. You can do it.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram illustrating a system interconnection inverter device according to a first embodiment;

FIG. 2 is a temperature curve diagram illustrating an operation of a temperature detection unit according to a second embodiment, and an operation explanatory diagram of an inverter unit;

FIG. 3 is a temperature curve diagram illustrating an operation of a temperature detection unit according to a third embodiment, and an explanatory diagram of an operation of an inverter unit;

FIG. 4 is a temperature curve diagram illustrating an operation of a temperature detecting unit according to a fourth embodiment, an operation explanatory diagram of an inverter unit, and an operational explanatory diagram of an opening / closing unit.

FIG. 5 is a circuit block diagram showing a conventional example.

[Explanation of symbols]

 Reference Signs List 3 Inverter section 5 Opening / closing means 6 Control circuit section 7 First temperature detecting section 8 Second temperature detecting section

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor ▲ Taka ▼ Masayuki Kuwa 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-house F term (reference) 5G053 AA14 BA06 CA02 CA07 EB01 EB09 5G066 HB06 HB07 5H007 AA05 AA06 AA17 BB07 CC03 DB05 DC08 FA13 FA18 5H420 BB17 CC03 DD03 EB39 FF14 FF23 LL07 LL09

Claims (4)

[Claims] 1. An inverter unit for converting DC power supplied from a solar cell or the like into AC power, switching means such as a relay for opening and closing a connection between an output of the inverter unit and a system power supply, and an operation of the inverter unit. A control circuit unit for controlling
A first temperature detection unit that detects the temperature of the switching element that forms the inverter unit, and a second temperature detection unit that detects the temperature of other heating components that form the inverter unit. A grid-connected inverter device that controls the output of an inverter unit based on information. 2. The output of the inverter unit is limited when one of the first temperature detecting unit and the second temperature detecting unit continuously detects a temperature equal to or higher than the temperature reduction detection level for a predetermined time or more. The system interconnection inverter device according to claim 1. 3. The output of the inverter unit when both the first temperature detection unit and the second temperature detection unit continuously detect a temperature lower than the temperature reduction release level for a certain period of time or more. 2. The system interconnection inverter device according to 1. 4. The output of the inverter unit is stopped when one of the first temperature detecting unit and the second temperature detecting unit continuously detects a temperature equal to or higher than the temperature abnormality detection level for a predetermined time or more. 2. The system interconnection inverter device according to claim 1, wherein the switching means is operated in an open state.