CN109904880A - A kind of recognition methods of photovoltaic DC-to-AC converter output high impedance - Google Patents
A kind of recognition methods of photovoltaic DC-to-AC converter output high impedance Download PDFInfo
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- CN109904880A CN109904880A CN201910227710.0A CN201910227710A CN109904880A CN 109904880 A CN109904880 A CN 109904880A CN 201910227710 A CN201910227710 A CN 201910227710A CN 109904880 A CN109904880 A CN 109904880A
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- high impedance
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- network voltage
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The invention discloses a kind of recognition methods of photovoltaic DC-to-AC converter output high impedance, can according to carry out Auto-matching with different impedances, thus the power grid of outputting high quality.The recognition methods includes the following steps: that A, inverter enter wait state and carry out grid-connected self-test；B, on the basis of the positive zero cross signal of power grid, sampling accesses the voltage value of unknown sensibility reciprocal；When system access unknown impedance, in 1/4 or 1/2 grid cycle of Check state or Normal state, the network voltage value that the continuous front and back two of acquisition is clapped, this two network voltage value clapped is calculated to the size of its difference after filtering, if difference meets the following conditions: 1/4 grid cycle network voltage difference is greater than NumA or 1/2 grid cycle network voltage difference is greater than NumB, and setting high impedance flag bit is 1；If the difference, which meets, is greater than NumC, setting high impedance flag bit is 2；C, with introducing simulated capacitance and using simulated capacitance backoff algorithm, adjust inverter PI control loop again according to different high impedance flag bits.
Description
Technical field
The invention belongs to photovoltaic DC-to-AC converter fields, are related to a kind of recognition methods of photovoltaic DC-to-AC converter output high impedance.
Background technique
Current photovoltaic DC-to-AC converter, especially in field of distributed type, due to being separated by very between inverter and AC transformer
Far, so that forming biggish inductance value between longer output AC line, if inverter cannot recognize that carry out this operating condition, hold very much
Cause generated energy low it is easier that over-current state occurs for machine, serious inverter may direct off-grid or can not grid-connected work.
It is more prominent in the more remote at village level power station of this problem often.
Summary of the invention
In order to solve the above-mentioned technical problem, mesh of the invention is to provide a kind of identification side of photovoltaic DC-to-AC converter output high impedance
Method, can according to carry out Auto-matching with different impedance, thus the power grid of outputting high quality.
In order to achieve the above objectives, the technical solution adopted by the present invention are as follows:
A kind of recognition methods of photovoltaic DC-to-AC converter output high impedance, includes the following steps:
A, inverter enters the grid-connected self-test of wait state progress, handles present high impedance flag bit clearing；
B, on the basis of the positive zero cross signal of power grid, sampling accesses the voltage value of unknown sensibility reciprocal；
When system access unknown impedance, in 1/4 or 1/2 grid cycle of Check state or Normal state, acquisition
This two network voltage value clapped, is calculated the size of its difference by the network voltage value that continuous front and back two is clapped after filtering, if
Difference meets the following conditions: 1/4 grid cycle network voltage difference is greater than NumA or 1/2 grid cycle network voltage difference is big
In NumB, then setting high impedance flag bit is 1；
If power grid shock range obviously becomes larger in Check state or Normal state, first setting high impedance flag bit is 1, so
Two voltage varieties clapped before and after 1/2 grid cycle compares afterwards, equally first filter and calculate its difference again, if the difference
Meet and be greater than NumC, then setting high impedance flag bit is 2；
Wherein, NumA, NumB, NumC are the foundations for determining which kind of high impedance flag bit, and the impedance of access is bigger, theoretically Num
Value is bigger, if access impedance comparison is small, the vibration of possible power grid is unobvious, so drawing in the case where high impedance mark is 1
Enter 1/4 period (corresponding NumA) and 1/2 period (corresponding NumB) judgment mechanism.Acquisition methods about Num value: unknown when accessing
When impedance, network voltage when obtaining the access that samples different impedances by writing host computer procedure is certain abundant by compensating
It measures.Theoretically analysis is exactly to be related to fuzzy control scope.
C, virtual electricity can be used with the simulated capacitance that inductance is mutually matched with introducing according to different high impedance flag bits
Hold backoff algorithm, adjusts inverter PI control loop again.
Further, if not can recognize that the high impedance flag bit in grid-connected moment, continue the step B and C；
If normal identification, the high impedance flag bit state of the step B identification is kept to continue to run.
Further, the high impedance flag bit is arranged according to the inductance value difference identified.
Further, in the step A, countdown carries out check state, high impedance flag bit, 1/2 grid cycle electricity
Net voltage difference and 1/4 grid cycle network voltage difference are zero；
The step B is executed at the end of countdown.
Further, in the step B, HPF filtering is carried out to the network voltage value is collected.
Further, in the step C, if the high impedance flag bit is 1, the first simulated capacitance is introduced, is adjusted inverse
Become device PI control loop；If the high impedance flag bit is 2, the second simulated capacitance is introduced, adjusts inverter PI control loop.
The present invention uses above scheme, has the advantages that compared with prior art
A kind of recognition methods of photovoltaic DC-to-AC converter output high impedance, can according to carry out Auto-matching with different impedance, draw
Enter the simulated capacitance that can be mutually matched with inductance, using simulated capacitance backoff algorithm, adjusts inverter PI control ring again
Road improves the output characteristics of photovoltaic DC-to-AC converter, thus the power grid of outputting high quality.
Detailed description of the invention
It, below will be to attached drawing needed in embodiment description in order to illustrate more clearly of technical solution of the present invention
It is briefly described, it should be apparent that, drawings in the following description are only some embodiments of the invention, general for this field
For logical technical staff, without creative efforts, it is also possible to obtain other drawings based on these drawings.
Fig. 1 is the flow chart according to a kind of recognition methods of photovoltaic DC-to-AC converter output high impedance of the application；
Fig. 2 a is the value of the display flag bit 1 and DeltaGridHalf when accessing 0.5MH impedance；
Fig. 2 b is the voltage and current waveform for accessing 0.5MH impedance；
Fig. 2 c is the expanded view of Fig. 2 b；
Fig. 3 a is the value of the display flag bit 2 and DeltaGridHalf when accessing 3.0MH impedance；
Fig. 3 b is the voltage and current waveform for accessing 3.0MH impedance；
Fig. 3 c is the expanded view of Fig. 3 b.
Specific embodiment
The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawing, so that advantages and features of the invention energy
It is easier to be understood by the person skilled in the art.It should be noted that the explanation for these embodiments is used to help
Understand the present invention, but and does not constitute a limitation of the invention.In addition, involved in the various embodiments of the present invention described below
And to technical characteristic can be combined with each other as long as they do not conflict with each other.
The present embodiment provides a kind of recognition methods of photovoltaic DC-to-AC converter output high impedance, key step is as follows:
1, enter the Wait state moment in inverter, need to handle present high impedance flag bit clearing, which mainly comes
It identifies different sensibility reciprocal values and sets；
2, identification process: on the basis of the positive zero cross signal of power grid, the voltage AD value of unknown sensibility reciprocal is accessed by DSP sampling, is used
FUZZY ALGORITHMS FOR CONTROL.
If when system access unknown impedance, in 1/4 or 1/2 power grid of Check state or Normal state
Period acquires the voltage AD values that continuous front and back two is clapped, by this two AD value clapped by HPF(high-pass filtering) after calculate its difference
Size, if difference meets the following conditions: the difference of 1/4 grid cycle network voltage is greater than NumA or 1/2 grid cycle electricity
The difference of net voltage is greater than NumB, that just sets Highimpedence=1, thinks that accessing impedance is less than 1.5Mh at this time；
If power grid shock range obviously becomes larger in Check state or Normal state, Highimpedence=1 is first set,
Then the two AD variable quantities clapped before and after 1/2 grid cycle compares, equally first filter and calculate its difference again, if the value is full
Foot is greater than NumC, that just sets Highimpedence=2, thinks that accessing impedance is more than 1.5Mh at this time；
3, according to different high impedance flag bits, PI control loop is adjusted again, while proposing using simulated capacitance backoff algorithm
This concept be mutually matched it can just with inductance.
If 4, not can recognize that high impedance flag bit in grid-connected moment, it will continue to 2, if normal identification, can protect
The flag bit state is held to continue to run.
Fig. 1 shows the detailed process of above-mentioned recognition methods.Shown in referring to Fig.1, the detailed process of the recognition methods are as follows:
Start；
Into wait state；
Self-test is carried out in countdown 30 seconds, high impedance flag bit is zero, and the difference of 1/2 grid cycle network voltage is zero, 1/4 electricity
The difference of net week phase network voltage is zero；
After countdown (i.e. timer=0), into check state or normal state；
To 1/4 or 1/2 grid cycle in Check state or Normal state, the electricity that continuous front and back two is clapped is acquired
AD value is pressed, by this two AD value clapped by HPF(high-pass filtering) after calculate the size of its difference, 1/4 grid cycle network voltage
Difference be denoted as DeltaGridQuarter=(GridSampAD [0]-GridSampAD [1]), 1/2 grid cycle network voltage
Difference be denoted as DeltaGridHalf=(GridSampAD [0]-GridSampAD [1])；
Fuzzy control is carried out according to resulting difference, specifically:
As DeltaGridQuarter > NumA or DeltaGridHalf > NumB, Highimpedence=1 is set；
The first simulated capacitance C1 is introduced, inverter PI control loop is adjusted, Repetitive controller improves the output feature of photovoltaic DC-to-AC converter；
As DeltaGridHalf > NumC, Highimpedence=2 are set；The second simulated capacitance C2 is introduced, inverter is adjusted
PI control loop, Repetitive controller improve the output feature of photovoltaic DC-to-AC converter.
It is inverse using photovoltaic of the invention when Fig. 2 a-2c and Fig. 3 a-3c respectively illustrate access 0.5MH, 3.0MH impedance
Become the test result of the recognition methods of device output impedance.It can find out from figure and access different impedances, network voltage also has not
With oscillation, DeltaGridHalf is represented in Fig. 2 a equal to 27765, sets high impedance flag bit 1；It is represented in Fig. 3 a
DeltaGridHalf is equal to 43326, sets high impedance flag bit 2.
The above embodiments merely illustrate the technical concept and features of the present invention, is a kind of preferred embodiment, and purpose exists
It cans understand the content of the present invention and implement it accordingly in person skilled in the art, protection of the invention can not be limited with this
Range.Equivalent transformation or modification made by all Spirit Essences according to the present invention, should all cover protection scope of the present invention it
It is interior.
Claims (6)
1. a kind of recognition methods of photovoltaic DC-to-AC converter output high impedance, which comprises the steps of:
A, inverter enters the grid-connected self-test of wait state progress, handles present high impedance flag bit clearing；
B, on the basis of the positive zero cross signal of power grid, sampling accesses the voltage value of unknown sensibility reciprocal；
When system access unknown impedance, in 1/4 or 1/2 grid cycle of Check state or Normal state, acquisition
This two network voltage value clapped, is calculated the size of its difference by the network voltage value that continuous front and back two is clapped after filtering, if
Difference meets the following conditions: 1/4 grid cycle network voltage difference is greater than NumA or 1/2 grid cycle network voltage difference is big
In NumB, then setting high impedance flag bit is 1；
If power grid shock range obviously becomes larger in Check state or Normal state, first setting high impedance flag bit is 1, so
Two voltage varieties clapped before and after 1/2 grid cycle compares afterwards, equally first filter and calculate its difference again, if the difference
Meet and be greater than NumC, then setting high impedance flag bit is 2；
C, it can be mended with the simulated capacitance that inductance is mutually matched using simulated capacitance with introducing according to different high impedance flag bits
Algorithm is repaid, adjusts inverter PI control loop again.
2. recognition methods according to claim 1, which is characterized in that if not can recognize that the high resistant in grid-connected moment
Anti- flag bit then continues the step B and C；If normal identification, the high impedance flag bit shape of the step B identification is kept
State continues to run.
3. recognition methods according to claim 1, which is characterized in that inductance of the high impedance flag bit according to identification
Value is different and is arranged.
4. recognition methods according to claim 1, which is characterized in that in the step A, countdown carries out check state,
High impedance flag bit, 1/2 grid cycle network voltage difference and 1/4 grid cycle network voltage difference are zero；
The step B is executed at the end of countdown.
5. recognition methods according to claim 1, which is characterized in that in the step B, to collecting the network voltage
Value carries out HPF filtering.
6. recognition methods according to claim 1, which is characterized in that in the step C, if the high impedance flag bit is
1, then the first simulated capacitance is introduced, inverter PI control loop is adjusted；If the high impedance flag bit is 2, it is empty to introduce second
Quasi- capacitor, adjusts inverter PI control loop.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112072696A (en) * | 2020-08-21 | 2020-12-11 | 爱士惟新能源技术(江苏)有限公司 | Method for calculating direct-current bus voltage under irregular power grid |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080143188A1 (en) * | 2006-12-06 | 2008-06-19 | Meir Adest | Distributed power harvesting systems using dc power sources |
| CN103401463A (en) * | 2013-07-25 | 2013-11-20 | 天津大学 | Miniature photovoltaic grid-connected inverter with optimized DC (Direct Current) bus capacitor and control method |
| EP2672621A1 (en) * | 2012-06-07 | 2013-12-11 | ABB Research Ltd. | Method for zero-sequence damping and voltage balancing in a three-level converter with spilt dc-link capacitors and virtually grounded LCL filter |
| CN104104255A (en) * | 2014-08-07 | 2014-10-15 | 江苏兆伏新能源有限公司 | Photovoltaic inverter inductance compensation control method |
| CN104158220A (en) * | 2014-08-28 | 2014-11-19 | 哈尔滨工业大学 | Method for controlling virtual reactance of photovoltaic grid-connected inverter |
| CN108880316A (en) * | 2018-07-17 | 2018-11-23 | 西安理工大学 | The grid-connection converter Predictive Control System and control method of compensation with voltage |
-
2019
- 2019-03-25 CN CN201910227710.0A patent/CN109904880B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080143188A1 (en) * | 2006-12-06 | 2008-06-19 | Meir Adest | Distributed power harvesting systems using dc power sources |
| EP2672621A1 (en) * | 2012-06-07 | 2013-12-11 | ABB Research Ltd. | Method for zero-sequence damping and voltage balancing in a three-level converter with spilt dc-link capacitors and virtually grounded LCL filter |
| CN103401463A (en) * | 2013-07-25 | 2013-11-20 | 天津大学 | Miniature photovoltaic grid-connected inverter with optimized DC (Direct Current) bus capacitor and control method |
| CN104104255A (en) * | 2014-08-07 | 2014-10-15 | 江苏兆伏新能源有限公司 | Photovoltaic inverter inductance compensation control method |
| CN104158220A (en) * | 2014-08-28 | 2014-11-19 | 哈尔滨工业大学 | Method for controlling virtual reactance of photovoltaic grid-connected inverter |
| CN108880316A (en) * | 2018-07-17 | 2018-11-23 | 西安理工大学 | The grid-connection converter Predictive Control System and control method of compensation with voltage |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112072696A (en) * | 2020-08-21 | 2020-12-11 | 爱士惟新能源技术(江苏)有限公司 | Method for calculating direct-current bus voltage under irregular power grid |
| CN112072696B (en) * | 2020-08-21 | 2022-02-11 | 爱士惟新能源技术(江苏)有限公司 | Method for calculating direct-current bus voltage under irregular power grid |
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