CN202267705U - Grid-connected inverter and island detection circuit thereof - Google Patents
Grid-connected inverter and island detection circuit thereof Download PDFInfo
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- CN202267705U CN202267705U CN2011203845834U CN201120384583U CN202267705U CN 202267705 U CN202267705 U CN 202267705U CN 2011203845834 U CN2011203845834 U CN 2011203845834U CN 201120384583 U CN201120384583 U CN 201120384583U CN 202267705 U CN202267705 U CN 202267705U
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Abstract
The utility model discloses a grid-connected inverter and an island detection circuit thereof. The island detection circuit comprises a sampling circuit and comparers, wherein the sampling circuit is used for acquiring grid voltages, and the two comparers are used for analyzing the acquired voltages. After signal processing, the fluctuation simulation of a grid can be effectively monitored by monitoring electric level changes of two output ends OUT1 and OUT2. If the grid runs normally, the output end OUT1 has high output, and the output end OUT2 has low output; when the grid is powered down to cause that voltage jump of the grid is high, the output end OUT1 has low output, and the output end OUT2 keeps the low electric level unchanged; and if the grid voltage drops suddenly, the output end OUT2 has high output, and the output end OUT1 keeps high output unchanged. In the process of monitoring OUT1and OUT2 by an MCU (Microprogrammed Control Unit) of the system, a certain algorithm is also added so as to prevent false detection caused by some disturbances on the grid. The island detection circuit disclosed by the utility model is capable of effectively monitoring the grid voltages, thereby preventing an island phenomenon from happening.
Description
Technical field
The utility model relates to power domain, in particular a kind of combining inverter and island detection circuit thereof.
Background technology
Island effect is meant combining inverter to mains supply the time, and because of reason interruption of power supply such as electric fault, maloperation or spontaneous combustion factors, but at this moment combining inverter still can continue to carry a certain proportion of electric energy to electrical network, thereby the isolated island phenomenon occurs.Island effect can bring serious hidden danger to equipment and personnel's safety.Behind the electrical network interruption of power supply, when the maintainer overhauls the power circuit of electrical network and power equipment, if combining inverter continues the accident that power supply can cause casualties; If combining inverter continues power supply, in case the power system restoration power supply, possibly there are bigger difference in the output voltage of electrical network and combining inverter and phase place, can produce very big dash current in a flash, and damage equipment.So behind grid power blackout, must stop the power supply of grid-connected photovoltaic system at once to electrical network.
Combining inverter generally can adopt passive dual mode with active to protect to be directed against this effect.Passive type protection generally is meant: when the electrical network interruption of power supply, can on amplitude, frequency and the phase parameter of line voltage, produce skip signal, judge whether dead electricity of electrical network through detecting skip signal.Active protection generally is meant: electrical network parameter is sent little undesired signal; Judge whether dead electricity of electrical network through detecting feedback signal, after combining inverter detects the electrical network interruption of power supply, can quit work immediately; The anti-isolated island of parallel network reverse is technological at present, and each company all captures.
The photovoltaic combining inverter standard of the current international practice has all been done requirement to combining inverter island detection function, and wherein IEEE Std2000-929 regulation is when the frequency of common point is outside 59.3-60.5Hz, and combining inverter should be stopped power supply in 6 cycles.Common combining inverter is because capacity is little; Characteristics such as cost height; Generally can not communicate by letter with communication system of power grids control system; Its island detection and resist technology mainly are based on self-examination (Local detection) but not the telecommunication technique (Remote detection) of inverter, and island detection research at present is devoted to the island detection function is integrated in the inverter control system.
Therefore, prior art awaits to improve and development.
The utility model content
The purpose of the utility model is to provide a kind of combining inverter and island detection circuit thereof, is intended to solve and detects combining inverter accurately when mains supply, the island effect that the outage back occurs.
The technical scheme of the utility model is following:
A kind of island detection circuit of combining inverter; It comprises signal processing circuit and microprocessor that sample circuit, comparer are formed; Said sample circuit, signal processing circuit and microprocessor are connected successively; Said signal processing circuit comprises first resistance, second resistance, second amplifier, the 3rd amplifier, a RC circuit, the 2nd RC circuit, the 3rd RC circuit and the 4th RC circuit; First resistance and second resistance are to the voltage dividing potential drop of sample circuit output terminal, and the voltage of sample circuit output terminal is linked into the positive input terminal of second amplifier and the negative input end of the 3rd amplifier through a RC circuit and the 2nd RC circuit correspondence respectively; Be linked into the negative input end of second amplifier and the positive input terminal of the 3rd amplifier through the 3rd RC circuit and the 4th RC circuit correspondence respectively through voltage after partial, the output terminal of second amplifier and the 3rd amplifier all is connected on the microprocessor.
The island detection circuit of described combining inverter, wherein, said sample circuit comprises first collection terminal and second collection terminal, and is connected on second pin and the 3rd pin of first amplifier, is in series with a plurality of resistance between first collection terminal and second pin; Also be in series with a plurality of resistance between second collection terminal and the 3rd pin; The 3rd pin also connects 2.5V voltage through resistance; First pin of first amplifier is signal output, and said first pin also feeds back on second pin through resistance.
The island detection circuit of described combining inverter, wherein, sample circuit is attenuated input signal the alternating voltage of peak-to-peak value less than 2.5V, and through external 2.5V power supply this AC signal is raised 2.5V.
The island detection circuit of described combining inverter, wherein, first resistance and second resistance carry out dividing potential drop to the output signal, the low 0.1V of the voltage after the dividing potential drop before the voltage ratio dividing potential drop.
A kind of combining inverter is characterized in that, is provided with above-mentioned island detection circuit in the said combining inverter.
The beneficial effect of the utility model: the utility model is gathered then line voltage through sample circuit and comparer and with two comparers the voltage that collects is carried out analyzing and processing.Through after the signal Processing, change the fluctuation situation that can effectively monitor electrical network through the level of monitoring two output terminal OUT1, OUT2.If during the electrical network normal operation, output terminal OUT1 is output as height, output terminal OUT2 is output as low; Suddenly change when high when electric network power-fail causes line voltage, output terminal OUT1 output is low, and output terminal OUT2 keeps low level constant; If line voltage bust, output terminal OUT2 are exported high, output terminal OUT1 keeps inconvenience output high.The MCU of system also adds certain algorithm to the observation process of OUT1, OUT2 and prevents that some interference on the electrical network from causing erroneous detection.This signal deteching circuit can effectively be monitored line voltage, thereby prevents the generation of isolated island phenomenon.
Description of drawings
Fig. 1 is the circuit theory diagrams of the line voltage sample circuit that provides of the utility model.
Fig. 2 is the input voltage waveform of sample circuit.
Fig. 3 is the sample circuit output voltage waveforms.
Fig. 4 is the circuit theory diagrams of the comparator signal treatment circuit that provides of the utility model.
Fig. 5 is the suddenly change voltage data oscillogram of comparer when high of line voltage.
Fig. 6 is the oscillogram of each point signal in the line voltage bust moment comparer.
Embodiment
For the purpose, technical scheme and the advantage that make the utility model is clearer, clear and definite, below develop simultaneously embodiment to the utility model further explain with reference to accompanying drawing.
The island effect major part causes the major network power down to form for reasons such as maloperation or spontaneous combustion factors.To the origin cause of formation we propose a kind of through the time real monitoring voltage ripple of power network method prevent the generation of island effect.The major network power down will inevitably cause the fluctuation of line voltage, and the inverter output voltage that is connected in parallel on the electrical network also can be affected thereupon, moment or uprise or step-down.Designing a monitor catches and grabs this saltus step process and survey electrical network.
The monitor principle analysis: testing circuit comprises signal processing circuit and the microprocessor that sample circuit, comparer are formed.Sample circuit is as shown in Figure 1.The input voltage of gathering from electrical network is the alternating current of 220V/50HZ, and input voltage waveform is as shown in Figure 2.Sample circuit is attenuated input signal the alternating voltage of peak-to-peak value less than 2.5V, and this AC signal is raised 2.5V.The waveform that output signal A is ordered is as shown in Figure 3.Send into microprocessor after the signal processing circuit analyzing and processing of the signal of output through the comparer composition, said microprocessor detects the variation of input signal, and makes corresponding response according to different variation control systems.
Continuation is referring to Fig. 1; Said sample circuit comprises two collection terminals; The first collection terminal 220AC-L and the second collection terminal 220AC-N, and be connected on second pin 2 and the 3rd pin 3 of the first amplifier UA, be in series with a plurality of resistance R between the first collection terminal 220AC-L and second pin 2; Also be in series with a plurality of resistance R between the second collection terminal 220AC-N and the 3rd pin 3.The 3rd pin also connects 2.5V voltage through resistance; First pin 1 of the first amplifier UA is signal output A point, and said first pin 1 also feeds back on second pin through resistance.
After collecting a little online voltage signal, the utility model adopts two comparers that the A point voltage that collects is carried out analyzing and processing.Like Fig. 4 is the comparator signal treatment circuit, comprises first resistance R 1, second resistance R 2, the second amplifier A, the 3rd amplifier B, a RC circuit, the 2nd RC circuit, the 3rd RC circuit and the 4th RC circuit.The one RC circuit is made up of R3 and C1 and R5 and C2; The 3rd RC circuit is made up of R4 and C3 and R6 and C4; The 4th RC circuit is made up of R7 and C5 and R9 and C6; The 2nd RC circuit is made up of R8 and C7 and R10 and C8.The one RC circuit is identical with the 4th RC circuit, and the 2nd RC circuit is identical with the 3rd RC circuit, and the 2nd RC circuit is different with a RC circuit.Electric capacity all is the same in the present embodiment, and the resistance in resistance ratio the 2nd RC circuit in the RC circuit is big.
First resistance R 1 and 2 pairs of A points of second resistance R signal carry out dividing potential drop, and the A point voltage is than the high 0.1V of voltage of dividing point B point after the dividing potential drop.The voltage of sample circuit output terminal (being the A point) is linked into the positive input terminal C of the second amplifier A and the negative input end F of the 3rd amplifier B through a RC circuit and the 2nd RC circuit correspondence respectively; Be linked into the negative input end D of the second amplifier A and the positive input terminal E of the 3rd amplifier B through the 3rd RC circuit and the 4th RC circuit correspondence respectively through voltage after partial (i.e. B point among the figure), the output terminal of the output terminal of second amplifier and the 3rd amplifier is connected to microprocessor.
The circuit monitoring line voltage just is that two different amplifier input ends that cause of RC circuit parameter are different to the response time of voltage fluctuation, and the response time is T=R*C.The response time that the response time that C, E are ordered among the figure orders than D, F is slow.Line voltage is in stable operating state during the electrical network operate as normal, and the A point voltage is higher than B point voltage 0.1V, and in like manner the C point voltage is higher than D point voltage 0.1V, and the F point voltage is higher than E point voltage 0.1V.The second amplifier A exports high level, the 3rd amplifier B output low level.
When electric network power-fail; If the voltage instantaneous on the electrical network uprises, the voltage that A point and B are ordered uprises suddenly, and for the second amplifier A: the response time that the response time of A being ordered owing to the C point orders to B than the D point is slow; So the voltage that moment D is ordered raises; And the voltage that C is ordered is constant, has just caused the D point voltage higher than C point voltage, causes second amplifier A upset by high step-down.In like manner, the response time that the response ratio F point that the E point is ordered to B among the 3rd amplifier B is ordered to A is slow, and the voltage that moment F is ordered raises, and the E point voltage is constant, and the F point voltage is still high than E point voltage, and the 3rd amplifier B still keeps output low level.
In like manner, when electric network power-fail, if the voltage instantaneous step-down on the electrical network; The voltage die that A point and B are ordered; For the 3rd amplifier B: since the low-response that the response ratio F point that E point is ordered to B is ordered to A, the voltage reduction that moment F is ordered, and the voltage that E is ordered remains unchanged; Just cause the F point voltage to be lower than the E point voltage, the amplifier output switching activity is uprised by low.The output voltage of in like manner analyzing the second amplifier A remains unchanged and exports height.
So through after the signal Processing, the level of the output terminal OUT1 through monitoring the second amplifier A, the output terminal OUT2 of the 3rd amplifier B changes the fluctuation situation that can effectively monitor electrical network.If during the electrical network normal operation, the output terminal OUT1 of the second amplifier A is output as height, the output terminal OUT2 of the 3rd amplifier B is output as low.Suddenly change when high when electric network power-fail causes line voltage, second amplifier A upset output terminal OUT1 output is low, and the output terminal OUT2 of the 3rd amplifier B keeps low level constant.
If the line voltage bust, the output terminal OUT2 upset of the 3rd amplifier B, output is high; The output terminal OUT1 of the second amplifier A remains unchanged, and output is high.The microprocessor MCU of system also should add certain algorithm to the observation process of the output terminal OUT2 of the output terminal OUT1 of the second amplifier A, the 3rd amplifier B and prevent that some interference on the electrical network from causing erroneous detection.
Fig. 5,6 is for simulated experiment result's data waveform figure.Analysis of experimental data: be the high voltage data oscillogram of line voltage sudden change like Fig. 5.Sinusoidal waveform is the voltage that A is ordered among Fig. 5, and corresponding C, D, OUT1 point voltage oscillogram.The voltage power down causes the line voltage sudden change high; Sudden change causes that D point voltage response is very fast, T1 to T2 in the time voltage be higher than the C point, cause amplifier to be overturn; The output terminal OUT1 of the second amplifier A produces a negative pulse in the meantime, and the output terminal OUT2 of this process the 3rd amplifier B keeps output end level.System catches and catches response is done in this saltus step with regard to reporting system processing.
Fig. 6 causes the line voltage bust voltage data oscillogram of moment for electric network power-fail.Sinusoidal waveform is the voltage that A is ordered among the figure, and corresponding constantly E, F, the oscillogram of OUT2 each point signal with the A point.Power down moment; The first positive input terminal E of the 3rd amplifier B and the first negative input end F cause T1 to be higher than the E point voltage to F point voltage between T2 to the reaction time difference of voltage jump; Cause the 3rd amplifier B upset; The output terminal OUT2 of the 3rd amplifier B exports a high impulse during this period of time, the output terminal OUT1 of this process second amplifier A keeps high level.System detects this saltus step and judges electric network power-fail, and reporting system is done the processing of response.
Experimental result shows that this signal deteching circuit can effectively monitor line voltage, thereby prevents the generation of isolated island phenomenon.
Should be understood that; The application of the utility model is not limited to above-mentioned giving an example; Concerning those of ordinary skills, can improve or conversion according to above-mentioned explanation, all these improvement and conversion all should belong to the protection domain of the utility model accompanying claims.
Claims (3)
1. the island detection circuit of a combining inverter; It is characterized in that; Comprise signal processing circuit and microprocessor that sample circuit, comparer are formed; Said sample circuit, signal processing circuit and microprocessor are connected successively; Said signal processing circuit comprises first resistance, second resistance, second amplifier, the 3rd amplifier, a RC circuit, the 2nd RC circuit, the 3rd RC circuit and the 4th RC circuit, and first resistance and second resistance are to the voltage dividing potential drop of sample circuit output terminal, and the voltage of sample circuit output terminal is linked into the positive input terminal of second amplifier and the negative input end of the 3rd amplifier through a RC circuit and the 2nd RC circuit correspondence respectively; Be linked into the negative input end of second amplifier and the positive input terminal of the 3rd amplifier through the 3rd RC circuit and the 4th RC circuit correspondence respectively through voltage after partial, the output terminal of second amplifier and the 3rd amplifier all is connected on the microprocessor.
2. the island detection circuit of combining inverter according to claim 1; It is characterized in that; Said sample circuit comprises first collection terminal and second collection terminal, and is connected on second pin and the 3rd pin of first amplifier, is in series with a plurality of resistance between first collection terminal and second pin; Also be in series with a plurality of resistance between second collection terminal and the 3rd pin; The 3rd pin also connects 2.5V voltage through resistance; First pin of first amplifier is signal output, and said first pin also feeds back on second pin through resistance.
3. a combining inverter is characterized in that, is provided with any described island detection circuit in the claim 1 to 2 in the said combining inverter.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011203845834U CN202267705U (en) | 2011-10-11 | 2011-10-11 | Grid-connected inverter and island detection circuit thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011203845834U CN202267705U (en) | 2011-10-11 | 2011-10-11 | Grid-connected inverter and island detection circuit thereof |
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| CN202267705U true CN202267705U (en) | 2012-06-06 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102393482A (en) * | 2011-10-11 | 2012-03-28 | 深圳市京泉华电子有限公司 | Grid-connected inverter and circuit for detecting island thereof |
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2011
- 2011-10-11 CN CN2011203845834U patent/CN202267705U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102393482A (en) * | 2011-10-11 | 2012-03-28 | 深圳市京泉华电子有限公司 | Grid-connected inverter and circuit for detecting island thereof |
| CN102393482B (en) * | 2011-10-11 | 2013-08-28 | 深圳市京泉华科技股份有限公司 | Grid-connected inverter and circuit for detecting island thereof |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: SHENZHEN JINGQUANHUA TECHNOLOGY CO., LTD. Free format text: FORMER NAME: SHENZHEN JINGQUANHUA ELECTRONICS CO., LTD. |
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| CP01 | Change in the name or title of a patent holder |
Address after: Jingquan Industrial Park No. 1 518110 Guangdong city of Shenzhen province Baoan District Guanlan Street Library Keng Xin Wei long Patentee after: Shenzhen JingQuanHua Electronics Co., Ltd. Address before: Jingquan Industrial Park No. 1 518110 Guangdong city of Shenzhen province Baoan District Guanlan Street Library Keng Xin Wei long Patentee before: Shenzhen Jingquanhua Electronics Co., Ltd. |
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Granted publication date: 20120606 |