CN114879806A - Photovoltaic static and dynamic MPPT disturbance observation and identification method and photovoltaic array power generation system - Google Patents
Photovoltaic static and dynamic MPPT disturbance observation and identification method and photovoltaic array power generation system Download PDFInfo
- Publication number
- CN114879806A CN114879806A CN202210640185.7A CN202210640185A CN114879806A CN 114879806 A CN114879806 A CN 114879806A CN 202210640185 A CN202210640185 A CN 202210640185A CN 114879806 A CN114879806 A CN 114879806A
- Authority
- CN
- China
- Prior art keywords
- disturbance
- value
- photovoltaic
- power
- photovoltaic power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003068 static effect Effects 0.000 title claims abstract description 105
- 238000000034 method Methods 0.000 title claims abstract description 72
- 238000010248 power generation Methods 0.000 title claims abstract description 19
- 230000008859 change Effects 0.000 claims abstract description 143
- 230000000630 rising effect Effects 0.000 claims description 30
- 230000008569 process Effects 0.000 claims description 24
- 230000002441 reversible effect Effects 0.000 claims description 13
- 230000009467 reduction Effects 0.000 claims description 7
- 230000003247 decreasing effect Effects 0.000 claims description 6
- 230000002829 reductive effect Effects 0.000 abstract description 12
- 238000012360 testing method Methods 0.000 abstract description 5
- 230000009471 action Effects 0.000 abstract description 3
- 238000005286 illumination Methods 0.000 description 18
- 230000007423 decrease Effects 0.000 description 11
- 238000004088 simulation Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 6
- 230000006872 improvement Effects 0.000 description 6
- 238000005070 sampling Methods 0.000 description 6
- 238000001514 detection method Methods 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 230000004044 response Effects 0.000 description 4
- 230000002159 abnormal effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000001788 irregular Effects 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 238000012937 correction Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000002620 method output Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/66—Regulating electric power
- G05F1/67—Regulating electric power to the maximum power available from a generator, e.g. from solar cell
-
- 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
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B10/00—Integration of renewable energy sources in buildings
- Y02B10/10—Photovoltaic [PV]
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Photovoltaic Devices (AREA)
- Control Of Electrical Variables (AREA)
Abstract
The invention discloses a photovoltaic static dynamic MPPT disturbance observation and identification method and a photovoltaic array power generation system, the identification method introduces a strategy mark to distinguish and switch the static dynamic disturbance identification method, and also introduces a disturbance mark to record default disturbance and unconventional disturbance, in the unconventional disturbance, when a photovoltaic power real-time value is increased, the voltage disturbance direction is reversed, and an unconventional disturbance state is preferentially adopted to test the system output power under dynamic weather, at the next moment, the disturbance mark and the disturbance direction at the previous moment are judged according to the fluctuation trend of the current photovoltaic power real-time value and the photovoltaic power change value, and the current disturbance mark and the disturbance direction are reconfigured, the disturbance action in power tracking is continuously corrected, the tracking efficiency of a photovoltaic maximum power point under dynamic weather is obviously improved, and two strategies of static identification and dynamic identification are considered simultaneously, and an additional hardware circuit is not required to be added, so that the cost of system equipment is reduced.
Description
Technical Field
The invention relates to the technical field of solar panels, in particular to a photovoltaic static and dynamic MPPT disturbance observation identification method and a photovoltaic array power generation system for realizing dynamic disturbance in a disturbance observation MPPT algorithm in the field of solar panels.
Background
In recent years, in some remote areas where conventional power grids cannot cover, solar panels are generally adopted to convert solar energy into electric energy and store the electric energy in storage batteries so as to solve the problems of domestic electricity and industrial electricity. Since the solar cell is affected by external factors such as light intensity and ambient temperature, the output power of the solar cell is often changed, and the voltage at the input end of the inverter is difficult to stabilize. It is generally understood that the higher the intensity of the light, the more electrical energy can be converted and stored, and that when the intensity of the light is not good, the less electrical energy can be relatively converted and stored. On one hand, the output power of the solar battery can be always kept above a certain value so as to meet the requirements of electric equipment; on the other hand, in order to enable the solar panel to output more electric energy at a higher voltage, a technical problem to be considered is how to increase the output power of the solar cell under the condition of a certain illumination intensity.
A Maximum Power Point Tracking (MPPT) system is an electrical system capable of adjusting the operating state of an electrical module to enable a photovoltaic panel to output more electric energy. Taking a solar cell panel as an example, the MPPT is realized by acquiring the power generation voltage of the solar cell panel in real time, tracking the highest voltage current value, detecting the current voltage change of the solar cell panel, and adjusting the duty ratio of a pulse width modulation signal according to the change of the current voltage change, so that the solar cell panel system outputs the maximum power, stores the power of a storage battery, and finally realizes the tuning of the working states of the solar cell panel, the storage battery and a load.
In the specific application of the MPPT, in consideration of the P-U curve characteristic of the photovoltaic cell itself, in practice, the MPPT is accompanied with the whole process of the photovoltaic power generation application, so as to maximize the power generation utilization of the photovoltaic cell. The commonly used MPPT algorithm is a static MPPT, and mainly enables equipment to have higher power generation efficiency under the conditions of better weather and weaker illumination intensity change, such as sunny weather, less wind and the like. However, when the weather is cloudy, has a fast change in illumination intensity, such as wind, the static MPPT is difficult to apply under the relatively dynamic weather change, and the error rate of recognition under the static MPPT is significantly increased due to the specific change of the photovoltaic cell caused by the weather change. Static algorithms such as disturbance observation method and conductance increment method in general algorithms have poor effect when applied to dynamic environment.
The test requirements of the current photovoltaic power generation system generally only require the efficiency of static MPPT, and the EN50530 standard does not require the efficiency of dynamic MPPT, so that in actual application, the low dynamic MPPT efficiency of the existing equipment generally has the condition of serious power generation loss under dynamic weather.
In view of the above problems, an easily conceivable improvement idea in the prior art is to improve an existing static MPPT algorithm to adapt to a scene under a dynamic condition, however, the existing improvement idea needs to be implemented by adding an additional hardware circuit, which inevitably increases the equipment cost of the photovoltaic power generation system.
In view of this, the prior art should be improved to solve the technical problem that the existing MPPT algorithm cannot use dynamic weather changes.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a photovoltaic static and dynamic MPPT disturbance observation and identification method and a photovoltaic array power generation system which take static identification and dynamic identification into consideration.
In order to solve the technical problems, the invention adopts a photovoltaic static and dynamic MPPT disturbance observation and identification method, which is used for realizing the maximum power output of a photovoltaic array under dynamic weather change, and the method comprises the following steps: a step S1 of configuring a policy identifier having at least two states, at least one of which corresponds to a static identification state and at least one of which corresponds to a dynamic identification state; step S2, collecting photovoltaic power real-time values according to a preset period, and configuring the strategy identification according to photovoltaic power change; when the policy identification is configured to be in a dynamic identification state, the method comprises the following steps: step S3 of configuring disturbance identifiers, wherein the disturbance identifiers record the current disturbance state, the disturbance identifiers have at least two states, at least one of which corresponds to a default disturbance state, and at least one of which corresponds to an unconventional disturbance state, wherein in the default disturbance state, the voltage disturbance direction is kept unchanged, and when the real-time value of the photovoltaic power is reduced, the voltage disturbance direction is reversed; in an unconventional disturbance state, when a photovoltaic power real-time value is increased, the voltage disturbance direction is reversed, and when the photovoltaic power real-time value is increased, the voltage disturbance direction is kept unchanged; step S4 of configuring the disturbance flag to be in an unconventional disturbance state under normal state; and S5, obtaining the power fluctuation size and trend in a period, configuring the current disturbance identifier according to the disturbance identifier and the disturbance direction of the previous period, and determining the current disturbance direction.
As one preferable embodiment of the present invention, in step S2, the process of configuring the policy identifier according to the photovoltaic power change specifically includes: and configuring the strategy identification according to the fluctuation of the photovoltaic power real-time value.
As a further preferable aspect of the present solution, the process of configuring the policy identifier according to the fluctuation of the photovoltaic power real-time value specifically includes: collecting continuous M according to a preset period 1 A sub-photovoltaic power real-time value, at least two photovoltaic power change values are obtained, the times that the photovoltaic power change values are larger than a first preset power comparison value Pa are recorded, if the times reach a first preset value, the strategy identification is configured as a dynamic identification,
and/or the presence of a gas in the gas,
collecting continuous M according to preset period 2 And acquiring at least two photovoltaic power change values, recording the times that the photovoltaic power change values are smaller than a first preset power comparison value Pa, and configuring the strategy identifier as a static identifier if the times reach a first preset value.
As still further preferable in this solution, in the process of configuring the policy identifier according to fluctuation of the real-time value of photovoltaic power, M 1 And M 2 Is a natural number of 3 or more, and M 2 Is greater than M 1 。
Still further preferably, in step S5, the step of obtaining the magnitude and the trend of the power fluctuation in a period, configuring the current disturbance flag according to the disturbance flag and the disturbance direction in the previous period, and determining the current disturbance direction specifically includes: if the value of the current photovoltaic power real-time value reduction is larger than a first preset power comparison value Pa, configuring a disturbance identifier as a default disturbance state, and enabling the disturbance direction to be reversed; if the absolute value of the change value of the current photovoltaic power real-time value is smaller than a first preset power comparison value Pa, judging a disturbance identifier of a previous period, if the disturbance identifier is in a default disturbance state, keeping the disturbance identifier and a disturbance direction unchanged, if the disturbance identifier is in an unconventional disturbance state, switching the disturbance identifier to be in the default disturbance state, and meanwhile reversing the disturbance direction; if the rising value of the current photovoltaic power real-time value is larger than a first preset power comparison value Pa, acquiring the change trend of the photovoltaic power real-time value and the photovoltaic power change value in a preset period, and then configuring the disturbance identifier and the disturbance direction.
Still further preferably, in step S5, the step of obtaining the magnitude and the trend of the power fluctuation in a period, configuring the current disturbance flag according to the disturbance flag in the previous period, and determining the current disturbance direction specifically includes: s51, real-time value P of photovoltaic power for any moment n Obtaining the first n-1 photovoltaic power real-time value P ═ { P ═ P 1 、P 2 、P 3 …P n-2 、P n-1 、P n And obtaining a photovoltaic power change value delta P { [ delta ] P { ] 1 、△P 2 、△P 3 …△P n-2 、△P n-1 A step of (1); s52, comparing the photovoltaic power change value delta P of the current period n-1 Comparing the value Pa with a first preset power, and if the value Delta P of the photovoltaic power change in the current period n-1 If the absolute value of (d) is smaller than the first preset comparison value Pa, go to step S53; if the photovoltaic power change value delta P of the current period n-1 Is negative, and Δ P n-1 If the absolute value of (d) is greater than the first preset comparison value Pa, go to step S54; if the photovoltaic power change value delta P of the current period n-1 If the comparison value is positive and greater than the first preset comparison value Pa, go to step S55; s53, ifIf the disturbance identifier of the previous period is in an unconventional disturbance state, setting the disturbance identifier as a default disturbance state and setting the disturbance direction as reverse disturbance, and if the disturbance identifier of the previous period is in the default disturbance state, maintaining the disturbance identifier and the disturbance direction unchanged; s54, setting the disturbance identifier as a default disturbance state, and setting the disturbance direction as reverse disturbance; and S55, acquiring the change trend of the photovoltaic power real-time value and the photovoltaic power change value in a preset period.
Still further preferably, in step S55, the step of obtaining the change trend of the real-time value of the photovoltaic power and the change value of the photovoltaic power in the preset period specifically includes: s551, obtaining M 1 Sub-photovoltaic power real-time value and M 2 Obtaining the change value of sub-photovoltaic power 1 If the change trend of the real-time value of the photovoltaic power is a discontinuous rising trend, the step S532 is executed, otherwise, the step S533 is executed; s552, if M is judged 1 If the change trend of the sub-photovoltaic power real-time value is a discontinuous rising trend, setting the disturbance identifier to be in a default disturbance state, and keeping the disturbance direction unchanged; s553, if M is judged 1 If the change trend of the real-time value of the sub-photovoltaic power is a continuous rising trend, configuring a disturbance identifier as an unconventional disturbance state and changing the disturbance direction when the disturbance identifier of the previous period is in a default disturbance state; and when the disturbance of the last period is identified as an unconventional disturbance state, judging according to the fluctuation trend of the photovoltaic power change value.
Still more preferably, in step S553, the step of determining according to the fluctuation trend of the photovoltaic power variation value specifically includes: at M 2 Setting a second predetermined power comparison value Pb if DeltaP n-1 -△P n-2 If the current disturbance identifier is greater than Pb, configuring the current disturbance identifier into a default disturbance state, and keeping the disturbance direction unchanged; if Δ P n-2 -△P n-1 If the disturbance identifier is greater than Pb, keeping the disturbance identifier unchanged, and enabling the disturbance direction to be reversed; if |. DELTA.P n-1 -△P n-2 If the absolute value is less than Pb, the current disturbance identifier is configured to be in a default disturbance state, and the disturbance direction is kept unchanged.
Still preferably, when the policy identifier is configured to be in a static identification state, the method includes the following steps: if the rising value of the current photovoltaic power real-time value is larger than a first preset power comparison value Pa, keeping the disturbance direction unchanged; if the value of the current photovoltaic power real-time value decrease is larger than a first preset power comparison value Pa, enabling the disturbance direction to be reversed; and if the absolute value of the change value of the current photovoltaic power real-time value is smaller than a first preset power comparison value Pa, keeping the disturbance direction unchanged.
As a second aspect of the present invention, a photovoltaic array power generation system for performing maximum power output by using the aforementioned photovoltaic static and dynamic MPPT disturbance observation and identification method is provided, which includes a photovoltaic array, an ac converter connected to an output end of the photovoltaic array, an MPPT controller also connected to the output end of the photovoltaic array and configured to drive a switch of the ac converter, and a load connected to an output end of the ac converter, where the MPPT controller implements the photovoltaic static and dynamic MPPT disturbance observation and identification method.
Compared with the prior art, the invention has the following beneficial technical effects due to the adoption of the technical scheme:
1. integrating the static identification method and the dynamic identification method, configuring a strategy identification for distinguishing the static identification and the dynamic identification, responding to the current weather change condition according to the change of the real-time value of the power of the photovoltaic equipment, and switching the static identification and the dynamic identification through switching the strategy identification in real time;
2. compared with the disturbance strategy in the prior art, when switching to dynamic identification, the strategy is to perform reverse interference on the photovoltaic working voltage along with the change of the real-time value of the photovoltaic power when the current scene is determined to be dynamic weather with rapid change of weather and illumination intensity, that is, when the real-time value of the photovoltaic power is increased, the voltage disturbance direction is reversed, and when the real-time value of the photovoltaic power is increased, the voltage disturbance direction is kept unchanged; in the process, a disturbance identifier for recording the current disturbance state is configured, after reverse disturbance, the change of the real-time value of the photovoltaic power and the change trend of the change value of the photovoltaic power are observed, whether the disturbance direction of the last period is correct or not is confirmed, the disturbance direction is continuously confirmed and corrected, the influence of weather dynamic change on the output power of the photovoltaic equipment is adapted, the maximum power point of the photovoltaic equipment is more quickly tracked, and the tracking efficiency and accuracy of MPPT are improved;
3. in the switching strategy of static identification and dynamic identification, the period for entering the dynamic identification is judged to be larger than the period for entering the static identification. Because the change of the illumination intensity is small in static weather, on the contrary, the change of the illumination intensity is large in amplitude and high in speed in dynamic weather, the condition of quitting the dynamic identification is improved by reducing the condition of entering the dynamic identification, the response sensitivity of the dynamic identification is improved, and the accuracy of static and dynamic identification switching is also improved;
4. the problem that an extra hardware circuit needs to be added to the improvement idea of adapting to dynamic identification in the prior art is avoided, the cost of system equipment is reduced, and meanwhile, the power generation efficiency of the photovoltaic system under the weather of dynamic change is remarkably improved only through the improvement of a strategy algorithm;
5. abandon and deal with the mppt disturbance observation discernment of dynamic weather change through the mode of repeatedly adjusting the disturbance step length, realize giving consideration to the tracking precision and the tracking efficiency of maximum power point simultaneously.
Drawings
Fig. 1 is a schematic diagram illustrating an exemplary output voltage-power characteristic curve of a conventional photovoltaic device;
fig. 2 is a diagram illustrating power variation and maximum power tracking efficiency variation curves under simulated conditions for applying an existing static MPPT strategy to dynamic weather conditions;
fig. 3 is a flow chart illustrating a flow of a static identification status in the photovoltaic static and dynamic MPPT disturbance observation and identification method according to a preferred embodiment of the present invention;
fig. 4 is a flowchart illustrating a process of dynamically recognizing a state in the photovoltaic static and dynamic MPPT perturbation and identification method according to a preferred embodiment of the present invention;
fig. 5 is a schematic diagram illustrating a power change and maximum power tracking efficiency change curve of the static and dynamic MPPT disturbance observation and identification method applied to a dynamic weather condition under a simulation condition.
Detailed Description
Embodiments of a photovoltaic dynamic and static MPPT disturbance observation and identification method and a photovoltaic array power generation system according to the present invention will be described below with reference to the accompanying drawings. Those of ordinary skill in the art will recognize that the described embodiments can be modified in various different ways, without departing from the spirit and scope of the present invention. Accordingly, the drawings and description are illustrative in nature and not intended to limit the scope of the claims. Furthermore, in the present description, the drawings are not to scale and like reference numerals refer to like parts.
It should be noted that, in the embodiments of the present invention, the expressions "first" and "second" are used to distinguish two entities with the same name but different names or different parameters, and it is understood that "first" and "second" are merely for convenience of description and should not be construed as limitations of the embodiments of the present invention, and the descriptions thereof in the following embodiments are omitted.
In cloudy, windy and rainy weather, for example, the root cause affecting the MPPT efficiency of the solar panel is that the illumination intensity changes frequently in dynamic weather, so that the illumination intensity received by the solar panel is very unstable. Due to the dynamic change of the illumination intensity, the accuracy and the efficiency of the original static MPPT algorithm are greatly influenced correspondingly.
The preferred embodiment of the present invention is an improvement to the general interference observation. First, a tracking strategy of a disturbance observation method commonly used in the prior art is described, which compares the current output power of a photovoltaic device (e.g., a solar cell panel) with the previous output power of a set time interval, so as to increase or decrease the operating voltage of the solar cell panel, thereby enabling the device to output near the maximum output power. For example, a certain time is set as t1, the current output power of the solar panel at the time is P1, the processor outputs a signal to increase the operating voltage of the solar panel by a preset increment, and the increment is set as Δ V. Next, a time interval Δ t is set, and a time t2(t2 is t1+ Δ t) is selected after the time interval Δ t from the time t1, and the output power P2 at the time t2 is detected.
Referring to fig. 1, fig. 1 is a schematic diagram illustrating an exemplary output voltage power characteristic curve of a general photovoltaic device. In an ideal tracking process, if the power variation Δ P (Δ P is P1-P2) is positive, it is considered that the power of the solar panel is in a decreasing trend along with the time change in the process from the previous time t1 to the next time t2, that is, the power variation process at this time is in the right half of the curve in fig. 1, at this time, the tracking strategy should reduce the operating voltage of the solar panel according to the increment Δ V, so as to interfere the power of the solar panel to the left half of the curve, and repeat the above detection process until the power variation Δ P is zero in the two previous and next detections. Correspondingly, if the power variation Δ P (Δ P is P1-P2) is negative, the power of the solar panel increases with time in the process from the previous time t1 to the next time t2, that is, the power variation process at this time is in the left half of the curve in fig. 1, and it is generally considered that the output power of the device is not yet maximum at this time and is still in the process of rising, so that the operating voltage of the solar panel is continuously increased according to the increment Δ V at this time, so as to interfere the power of the solar panel to the right half of the curve, and the above detection process is repeated until the power variation Δ P is zero in the two previous and next detections.
It can be seen that Maximum Power Point Tracking (MPPT) is here to achieve the output power of the solar panel, and can be maintained as close to the maximum power point as possible. And the disturbance concept is the aforementioned process of amplifying or reducing the working voltage of the solar panel according to the power change of the solar panel. The specific judgment and adjustment of the disturbance are realized by observing the PV power and determining the magnitude and the direction of the next PV voltage disturbance according to the change of the power. Specifically, if the current PV power continues to increase after the disturbance, that is, the current power has not reached the maximum power point, the PV voltage disturbance direction is unchanged (the device operating voltage keeps increasing or decreasing), and conversely, if the PV power decreases after the disturbance, the PV voltage disturbance direction is changed to reverse disturbance (the device operating voltage is corrected to decrease from the increase, or corrected to positive from the decrease). In general, the direction of a disturbance with increasing voltage is defined as a positive disturbance, and the direction of a disturbance with decreasing voltage is defined as a negative disturbance.
Under static MPPT, due to the fact that power changes infrequently, the disturbance observation method can guarantee better accuracy, and under dynamic MPPT, the power and open-circuit voltage of a PV curve are changed all the time, so that the PV disturbance direction is easy to judge wrongly in the adjustment process based on the disturbance observation method. For example, one common failure condition is that the current PV power continuously rises, regardless of positive or negative disturbances, and at the next time the PV power is in a rising state. And if the disturbance direction of the PV voltage is wrong, the low MPPT efficiency finally is influenced, and the power generation is influenced.
In particular. Simulating the condition that the existing static identification is applied to the dynamic weather, and setting the simulation test conditions as the rated MPPT power of 11000W, the rated photovoltaic voltage of 600V, the measurement period of 0.2 second, and the minimum illumination intensity of 100W/m 2 The maximum illumination intensity is 500W/m 2 The number of cycles was 10, the rise time and the fall time were 20 seconds, and the strong light retention time and the weak light retention time were 10 seconds. The simulation data shown in table 1 were obtained according to the above simulation test conditions:
TABLE 1
Fig. 2 is a schematic diagram illustrating a power change and a maximum power tracking efficiency change curve under simulation conditions when applying a conventional static MPPT strategy to dynamic weather conditions according to data in table 1. The curves shown in the figure are respectively a theoretical Power value curve (Pmp), a theoretical operating Voltage value curve (Vmp), an actual Power value curve (Power), an actual operating Voltage value curve (Voltage), and an MPPT efficiency value curve (MPPT eff). Referring to table 1 and fig. 1, it can be seen that:
(1) at the time of T0, the actual working voltage is 542.17V, the actual power is 1355.43W, the theoretical value of the working voltage is 551.37V, the theoretical value of the power is 1357.15W, and at the moment, the Mppt efficiency of the system is 99.89%, and the system basically works at the maximum Mppt point;
(2) at time T1, the actual operating voltage is 534.73V, the actual power is 1563.55W, the theoretical value of the operating voltage is 557.22V, and the theoretical value of the power is 1576.18W, so that PV voltage reduction Δ V (V1-V0) is-7.44V, and power change Δ P (P1-P0) is 208.13W, that is, the operating voltage of the system decreases, and the output power of the system increases, according to the foregoing existing interference strategy, since the output power of the system decreases with the decrease of the operating voltage, looking back to fig. 1, the power change at this time should be located in the right half of the curve of fig. 1, and then the interference strategy at this time should be to continuously decrease the operating voltage of the system;
(3) at the time of T2, the actual working voltage is 526.26V, the actual power is 1763.50W, the theoretical value of the working voltage is 562.21V, the theoretical value of the power is 1796.89W, meanwhile, the PV voltage is reduced by-8.47V, the power change DeltaP is 199.95W, the working voltage of the system is reduced at the time of T2, the output power of the system is still increased at the time of T1, and the strategy is the same as the time of T1, at this time, the working voltage is continuously reduced; however, as shown in the graph 1, the theoretical operating voltage is from 551.37V to 557.22V to 562.21V, i.e., the theoretical operating voltage is in an increasing trend.
Referring to the interference process from the time T0 to the time T2, according to a common Mppt interference recognition algorithm, when the photovoltaic operating voltage is reduced and the system output power is increased all the time, a strategy can interfere with the operation voltage to move towards the reduction direction all the time, further, the photovoltaic operating voltage is reduced from 542.17V to 391.85V in the process from the time T1 to the time T20, but the difference is far from the simulation result of the theoretical voltage value, and the Mppt efficiency is reduced from 99.89% to 83.20% as the actual Vmp voltage is more deviated.
For another example, in the chinese patent with publication number CN103529900B, an MPPT meter is disclosedThe method discloses the optimization of dynamic tracking performance, and is characterized in that in a set period, if the power change delta P is small, the disturbance step length delta V of a disturbance observation method output by a PI controller is small ref The steady state fluctuation of the power is small; on the contrary, when the sunlight is suddenly changed and the power change delta P is relatively large, the disturbance step length delta V of the disturbance observation method output by the PI controller ref The output power is then large, reaching the maximum of the photovoltaic array quickly. That is, the static MPPT in this strategy deals with the dynamic tracking means by changing the perturbation step size Δ V ref In a manner described above.
However, the voltage increment Δ V is considered to be that if the voltage increment Δ V is too large, the output power of the solar cell panel repeatedly floats near the maximum frequency point, and conversely, if the voltage increment Δ V is too small, although the tracking accuracy is ensured to a certain extent, the time efficiency prolongs the maximum power point tracking time, and when the voltage increment Δ V is too small, the tracking effect of the maximum power point is greatly influenced in a scene where the maximum power point changes frequently.
As can be seen from the above simulations and examples, the conventional static MPPT interference recognition strategy cannot be applied to the reason of dynamic weather: when the static interference strategy is applied to dynamic weather, the existing strategy only makes a judgment according to power change, but cannot identify and respond to the situation of rapid power change caused by sudden increase of illumination intensity, in other words, the existing strategy cannot distinguish whether the current power rise of power is due to the rise of working voltage or the rapid change of weather or the combined action of the two, so that as described above, the disturbance direction is always kept unchanged as long as the work rises after disturbance, and the working voltage is continuously reduced. On the other hand, in the disturbance strategy in the prior art, the means for dynamic tracking is single, and it is difficult to consider both the tracking accuracy and the tracking efficiency of the maximum power point only by changing the disturbance step length.
In view of the above technical problems, it is desirable to provide an identification method for considering both static MPPT and dynamic MPPT, which can achieve the following improvements:
1) under the non-dynamic weather, a static MPPT disturbance method is adopted for identification;
2) in dynamic weather, quitting static MPPT disturbance and introducing a dynamic identification strategy;
3) in the dynamic identification strategy, since it is determined that the current weather condition is in a dynamically changing state, an unconventional disturbance strategy is attempted to be performed on the current operating voltage. And continuously determining whether the last disturbance direction is the correct direction according to the further change of the disturbed power, and continuously correcting the disturbance direction in dynamic recognition to finally enable the equipment to always maintain the maximum power point for output.
Firstly, in order to respond to different weather changes, distinguish static weather from dynamic weather, and adapt corresponding identification strategies according to different weather conditions, in a preferred embodiment of the invention, strategy identification is introduced. In a preferred embodiment, the policy identification includes two states, one is a static identification state that accounts for static weather conditions and the other is a dynamic identification state that accounts for dynamic weather conditions. In a specific implementation, for example, a dynamic flag may be configured as a policy identifier, and according to different assignments of dynamic flag variables, whether a current policy corresponds to a static identification state or a dynamic identification state is determined. For example, the static recognition state is set when the dynamic flag is 0, and the dynamic recognition state is set when the dynamic flag is 1. Then, the current value of the strategy identification is changed by setting different judgment conditions so as to guide the static and dynamic MPPT disturbance observation and identification method to enter or exit a static and dynamic identification state. In other further embodiments of the present invention, the policy identifier (dynamic flag) may be expanded as needed, for example, the static identifier and the dynamic identifier may be further subdivided according to the difference of the photovoltaic conditions in different regions, and accordingly, more values may be given to the dynamic flag to distinguish more identification states. In this document, the description is made by taking an example including only the static recognition state and the dynamic recognition state.
After the policy identifier is set, corresponding determination conditions need to be configured for different policy identifiers or different identification states. In a preferred embodiment of the present invention, the photovoltaic power real-time value of the device is periodically collected, and the policy identifier is configured according to the fluctuation of the photovoltaic power real-time value. Specifically, according to a preset period, continuous M is collected 1 Acquiring a secondary photovoltaic power real-time value, acquiring at least two photovoltaic power change values, recording the times that the photovoltaic power change values are greater than a first preset power comparison value Pa, and if the times reach a first preset value, configuring the strategy identifier as a dynamic identifier; and, according to a preset period, acquiring continuous M 2 And acquiring at least two photovoltaic power change values, recording the times that the photovoltaic power change values are smaller than a first preset power comparison value Pa, and configuring the strategy identifier as a static identifier if the times reach a first preset value.
Referring to the foregoing, in dynamic weather, the operating power of the system changes rapidly, and in the above strategy, in the determination of whether the current environment meets the dynamic weather, the power fluctuation of the current system is obtained through real-time values of the photovoltaic power in multiple cycles. The fluctuation is determined by the number of the power change values which are sampled for a plurality of times and exceed a preset power comparison value. For example, a sampling period is set to be 1 second, and three consecutive photovoltaic power real-time values (P) are acquired 1 、P 2 、P 3 ) And obtaining the photovoltaic power variation value (| P) 2 -P 1 |、|P 3 -P 2 If the photovoltaic power change values of the two times are larger than the preset power comparison value 5w, determining that the output power of the current equipment fluctuates and meeting the dynamic identification condition; correspondingly, if the fluctuation of the photovoltaic power change value is small, the current weather is considered as static weather, and static identification is applicable. It is also illustrated by the foregoing example, that if the photovoltaic power variation value (| P) is obtained twice 2 -P 1 |、|P 3 -P 2 |)And if the power values are less than the preset power comparison value 5w, the static identification condition is determined to be met. And after static weather and dynamic weather are identified, the strategy identification is correspondingly assigned, and then the system is switched to a corresponding interference identification state. In the embodiment with more collection times, the number of the photovoltaic power change values which are greater than or less than the preset power comparison value is set to meet a certain requirement, and the photovoltaic power change values are used as corresponding identification state switching conditions.
It should be noted that, in a static weather environment, for example, conditions such as illumination and wind power are not constant, so to improve the accuracy of system determination, the sampling frequency of the initial determination should be increased, and the determination frequency of the photovoltaic power variation value and the preset power comparison value should be correspondingly increased, so as to improve the accuracy of dynamic weather identification, but the sampling frequency of the initial determination should not be too high, and too many determination frequencies would reduce the response of the system to weather variation
Continuing with the switching of the static and dynamic identification policy. A common judgment logic is used for respectively and independently judging a static identifier and a dynamic identifier, namely, after the static identifier enters a static identifier state, the static identifier stops entering static identification, only whether the static identifier state exits and the dynamic identifier state transitions is judged, after the dynamic identifier state enters, the dynamic identifier stops entering dynamic identification, and whether the dynamic identifier state exits and the static identifier state transitions is judged. For example, when judging M 1 And a plurality of photovoltaic power comparison values are obtained, wherein the times greater than a first preset power comparison value Pa meet preset times, the dynamic identification state is switched to, and then, the dynamic identification state is switched to until M is obtained 2 And after the photovoltaic power real-time values are obtained, and a plurality of photovoltaic power comparison values are obtained, wherein the times smaller than the first preset power comparison value Pa meet the preset times, the dynamic identification state is exited and the static identification state is switched to. The disadvantage of this strategy is that there is a high probability of misjudgment and frequent switching of the static and dynamic states. For example, six consecutive power variation values (Δ P) are acquired in a preset 1-second period 1 、△P 2 、△P 3 、△P 4 、△P 5 、△P 6 ) And if the third power change value is larger than the preset power comparison value by 5w, judging to enter a dynamic identification state, and if the third power change value is smaller than the preset power comparison value, judging to enter a static identification state. If the power change value of the first three times is within the six power change values, the power change value of the first three times is delta P 1 、△P 2 、△P 3 If the power change values are all larger than the preset power comparison value, the system sets the strategy identifier as a dynamic identification state at the moment, and then the power change value delta P is changed three times 4 、△P 5 、△P 6 If the value is less than the preset power comparison value, the system needs to configure the policy identifier back to the static identification state.
To solve this problem, in the preferred embodiment of the present invention, the determination processes of static identification and dynamic identification are set in parallel, that is, the static identification and dynamic identification that synchronize the real-time value of the photovoltaic power are kept, and in order to avoid the above-mentioned policy disadvantage, the sampling frequency and the comparison frequency are set. The foregoing disadvantages are caused by the similar entering and exiting conditions of the static identification state and the dynamic identification, and the set collection times and comparison times are the same, so that the system is easily switched between the two identification states repeatedly, and in the preferred embodiment of the present invention, the idea of solving the problem includes the following two aspects:
1) setting different photovoltaic power real-time value acquisition times and comparison times of photovoltaic power change values for the static identification state and the dynamic identification state;
2) setting the collection times of the photovoltaic power real-time values which are judged to enter the dynamic identification state to be smaller than the collection times of the photovoltaic power real-time values which enter the static identification state;
for example, a real-time value of the photovoltaic power is acquired 10 times within 10 seconds, and if it is determined that a variation value of the photovoltaic power is greater than a preset power comparison value 5 times, the configuration policy is identified as a dynamic identification state, and if it is determined that the dynamic identification is exited, a real-time value of the photovoltaic power needs to be acquired 20 times within 20 seconds, and if it is determined that a variation value of the photovoltaic power is greater than a preset power comparison value 10 times, the state is switched to a static identification state. And specific sampling times and comparison times can be adjusted according to different photovoltaic conditions, different regions and different sensitivity requirements of the system. After the setting, the judgment condition for entering the dynamic recognition is reduced, and the judgment condition for exiting the dynamic recognition is improved. Through the parallel configuration of static and dynamic recognition states, the accuracy of static and dynamic weather response can be improved while the sensitivity of the dynamic weather response is improved.
And finishing the strategy identification for switching the static identification state and the dynamic identification state. The strategies for static identification and dynamic identification in the preferred embodiment of the present invention are described below.
Static identification is said first. Referring to fig. 3, fig. 3 is a flow chart illustrating a flow of static identification status in the photovoltaic static and dynamic MPPT disturbance observation identification method according to a preferred embodiment of the present invention, in which the static identification includes the following steps: if the rising value of the current photovoltaic power real-time value is larger than a first preset power comparison value Pa, keeping the disturbance direction unchanged; if the value of the current photovoltaic power real-time value reduction is larger than a first preset power comparison value Pa, enabling the disturbance direction to be reversed; and if the absolute value of the change value of the current photovoltaic power real-time value is smaller than a first preset power comparison value Pa, keeping the disturbance direction unchanged.
Specifically, referring back to fig. 1, in the static identification state, if the rising value of the real-time value of the photovoltaic power is greater than the first preset power comparison value Pa, that is, the fluctuation of the current real-time value of the photovoltaic power is in a rising trend, and the rising amplitude is large, then the change of the power at this time corresponds to the left half curve in fig. 1, and the strategy determines that the voltage should be increased, that is, the forward disturbance is maintained, so that the system output power further tracks the maximum output power. Similarly, if the value of the drop of the photovoltaic power real-time value is greater than the first preset power comparison value Pa, the opposite is to indicate that the fluctuation of the current photovoltaic power real-time value is in a falling trend, and the drop amplitude is large, at this time, the change of the power should correspond to the curve of the middle-right half of the leg 1, and the strategy judges that the voltage should be reduced, so that the output power of the system returns to the maximum output power point, that is, the disturbance direction is changed into negative disturbance. In another case, if the photovoltaic power real-time value is in a trend of rising or falling, but the rising or falling amplitude does not reach the first preset power comparison value Pa, in this case, it can be considered that the current system power fluctuates but the fluctuation amplitude is small, the current disturbance direction is not easily changed at this time, and the current disturbance direction is maintained, and the adjustment is performed according to the strategies of the two cases according to the further change of the photovoltaic power real-time value.
In general, in static weather, the change amplitude of weather factors such as illumination is small, and the change frequency is low, so that in a strategy in a static identification state, the direction of voltage disturbance is maintained or corrected only according to the change between two consecutive photovoltaic power real-time values. Then again, the dynamic recognition state in dynamic weather. Fig. 4 is a flowchart illustrating a process of dynamically recognizing a state in the photovoltaic static and dynamic MPPT perturbation and identification method according to a preferred embodiment of the present invention. In the preferred embodiment, the perturbation concept in the dynamic recognition state is: when the current environmental factor is determined to be dynamic weather, considering the influence of weather change on system power, preferentially considering to try to carry out disturbance according to a strategy opposite to a default disturbance direction, and in subsequent disturbance, according to a disturbance strategy and a disturbance direction in a preorder disturbance state, and according to fluctuation and a fluctuation trend of a current photovoltaic power real-time value, carrying out adjustment and correction on a disturbance strategy and a disturbance direction.
Referring back to table 1 and fig. 1, during the period from time T0 to time T2, the system operating power still rises due to the rapid change of the illumination intensity even if the direction of the disturbance is wrong. Factors that are difficult to distinguish by a single perturbation strategy include:
1) the current system work is increased, which is the result of the correct action of the disturbance strategy or is caused by the rapid change of the illumination intensity;
2) the fact that whether the strategy of the previous disturbance is correct or not cannot be judged according to the power change causes a situation of error and error, and for the correction of the strategy, the change needs to occur again after the power stops fluctuating.
For the above reasons, in the preferred embodiment of the present invention, a disturbance flag is introduced for recording the current disturbance state, separately from the current disturbance direction. The disturbance flag includes two states, one is a default disturbance state and one is an irregular disturbance state. In a specific implementation, for example, the MpptState may be configured as a disturbance identifier, and according to different assignments of the MpptState variable, it is determined whether the current dynamic disturbance policy corresponds to a default disturbance state or an irregular disturbance state. For example, the default perturbation state is set when MpptState is 0, the irregular perturbation state is set when MpptState is 1, and the default MpptState has a value of 0. Then, the current value of the strategy identification is changed to guide the static and dynamic MPPT disturbance observation and identification method to adopt a default disturbance state or an unconventional disturbance state in a dynamic identification state.
The default disturbance state is also the same as the conventional strategy, when the pv power real-time value is increased, the voltage disturbance direction is kept unchanged, and when the pv power real-time value is decreased, the voltage disturbance direction is reversed. Then the unconventional disturbance state, i.e. contrary to the default disturbance state, makes the voltage disturbance direction when the real-time value of the photovoltaic power increases, and keeps the voltage disturbance direction unchanged when the real-time value of the photovoltaic power decreases. The strategy of actively adopting the reverse disturbance can be regarded as a heuristic for the system power change, and the system power change after the reverse disturbance is explored. If the system power changes after the abnormal disturbance, whether the result of the system power changes is consistent with the expectation or not. For example, if the power of the system increases after the reverse disturbance, it indicates that the strategy of the reverse disturbance and the current disturbance direction are the correct directions, and if the power of the system is not as expected after the reverse disturbance, it is likely that the current disturbance strategy and/or disturbance direction are wrong. And when the power change of the system after the reverse disturbance is not as expected, the disturbance identifier and the disturbance direction are readjusted according to the size and the trend of the power fluctuation in a certain period, and the next step of disturbance is carried out.
This is specifically illustrated with reference to fig. 4. In the preferred embodiment, the identification policy under dynamic weather is: if the value of the current photovoltaic power real-time value reduction is larger than a first preset power comparison value Pa, configuring a disturbance identifier as a default disturbance state, and enabling the disturbance direction to be reversed; if the absolute value of the change value of the current photovoltaic power real-time value is smaller than a first preset power comparison value Pa, judging a disturbance identifier of a previous period, if the disturbance identifier is in a default disturbance state, keeping the disturbance identifier and a disturbance direction unchanged, if the disturbance identifier is in an unconventional disturbance state, switching the disturbance identifier to be in the default disturbance state, and meanwhile reversing the disturbance direction; if the rising value of the current photovoltaic power real-time value is larger than a first preset power comparison value Pa, acquiring the variation trend of the photovoltaic power real-time value and the photovoltaic power variation value in a preset period, and then configuring the disturbance identifier and the disturbance direction.
In the preliminary judgment, the change amplitude of the real-time value of the photovoltaic power is judged. There are three cases:
1) if the photovoltaic power real-time value is changed from rising to falling after the last disturbance and the falling amplitude exceeds the preset power comparison value Pa, the system output power passes through the maximum power point after the last disturbance, and the disturbance direction is reversed at the moment according to the default disturbance state, so that the system power returns to the maximum power point as soon as possible;
2) if the rising or falling amplitude of the photovoltaic power real-time value is smaller than the first preset power comparison value Pa, that is, the current power changes, but the change amplitude is not large, the disturbance identifier at this time needs to be referred to. Recording a preorder disturbance strategy by the disturbance identifier, and under the condition that the fluctuation of a real-time value of the power is small, if the previous disturbance mode is default disturbance, indicating that the preorder default disturbance result is that the system power tends to be stable near a maximum power point, indicating that the default disturbance mode and the disturbance direction are both correct, and keeping the disturbance identifier and the disturbance direction unchanged; if the previous disturbance mode is unconventional disturbance, under the condition that the fluctuation of the real-time power value is small, the system power tends to be stable near the maximum power point after disturbance, the default disturbance state is recovered at the moment, and the disturbance direction is reversed, so that the system power reaches the maximum power tracking point as soon as possible;
3) if the rising value of the current real-time power value is greater than the first preset power comparison value Pa, that is, the power change of the system is still in a rising trend after the previous disturbance, and the fluctuation amplitude is large, referring back to fig. 1, the current power change of the system is in a curve in the left half part of fig. 1, and at this time, the current power change is not judged according to the magnitude of the two real-time power values, but the change trend of the power in a certain period needs to be obtained to judge whether the disturbance state and the disturbance direction in the previous period are correct.
In particular the third case. Photovoltaic power real-time value P for any moment n According to a preset sampling period, acquiring a photovoltaic power real-time value P (n-1 times) before the moment as { P ═ P 1 、P 2 、P 3 …P n-2 、P n-1 、P n Obtaining the photovoltaic power change value delta P { [ delta ] P at n moments 1 、△P 2 、△P 3 …△P n-2 、△P n-1 }. In the third case, since at the current time, there is P n -P n-1 If the power is larger than Pa, the recent n-time power change trend can be obtained according to the photovoltaic power change value at n moments. There are two possibilities here:
possibly, at one or n moments, a part of power change values are positive, a part of power change values are negative, that is, in n times of power change, power change at some moments is rising, and power change at some moments is falling, which indicates that the system output power is close to the maximum power point, and then the disturbance identifier is set to be in a default disturbance state, and the disturbance direction is kept unchanged;
in two or n times, all the power change values are positive, that is, the power at all times in n changes of the power is in an increasing trend, and then the power is considered to be in a continuous or continuous increasing trend.
In the second possibility, the output power of the system is in the process of continuously increasing, but at this time, it still cannot be determined what disturbance strategy and disturbance direction should be adopted at the current time. Because, as in the example of static identification, it is still necessary to determine that the system power is continuously increasing due to the dayThe rapid change of gas is also due to the preceding perturbation strategy. Because of the disturbance flag, in the preferred embodiment, the preamble disturbance flag needs to be determined to determine when the system output power continuously increases. When the disturbance identifier of the previous period is in a default disturbance state, configuring the disturbance identifier as an unconventional disturbance state according to the idea of preferentially trying the unconventional disturbance state, changing the disturbance direction, and trying direction disturbance; when the disturbance identifier of the previous period is in the abnormal disturbance state, it indicates that the output power of the system is still in the rising trend under the strategy of the abnormal disturbance, and at this time, on the premise that the output power of the system keeps rising, it is necessary to further judge how much the output power of the system rises, in other words, it is necessary to judge the photovoltaic power change value Δ P at the current time n-1 The value Δ P of the change in photovoltaic power at the previous moment n-2 The size of the phase comparison.
If Δ P n-1 -△P n-2 And if the current disturbance identifier is greater than Pb, the current disturbance identifier is configured to be in a default disturbance state, and the disturbance direction is kept unchanged. In this case, the photovoltaic power is in a continuous rising trend, the change value of the photovoltaic power is increased, and the increase of the change value of the power exceeds the preset power comparison value Pb, which indicates that the previous disturbance direction is correct, the disturbance identifier is corrected to be in a default disturbance state, the disturbance direction is kept unchanged, and the system continues to track the maximum power point.
If Δ P n-2 -△P n-1 And Pb, keeping the disturbance identifier unchanged and reversing the disturbance direction. In this case, it is described that although the current system power is continuously increasing, the amount of increase is decreasing, and the decrease of the power variation value exceeds the preset power comparison value Pb, it is described that the perturbation strategy in the previous cycle is correct, but the perturbation direction is wrong, at this time, the perturbation flag is kept unchanged, and the perturbation direction is reversed.
If |. DELTA.P n-1 -△P n-2 If the absolute value is less than Pb, the current disturbance identifier is configured to be in a default disturbance state, and the disturbance direction is kept unchanged. In this case, the system photovoltaic power is in a continuously rising trend, but beforeCompared with the secondary power change value, the rising or falling amplitude of the current power change value is less than the preset power comparison value Pb, and it can be considered that the rising amplitude of the photovoltaic power real-time value is slowed down at the moment, then the default disturbance state is switched, and the disturbance direction is kept unchanged.
The dynamic disturbance observation and identification method is simulated according to the same conditions as the simulation. The rated MPPT power is 11000W, the rated photovoltaic voltage is 600V, the measurement period is 0.2 second, and the minimum illumination intensity is 100W/m 2 The maximum illumination intensity is 500W/m 2 The number of cycles was 10, the rise time and the fall time were 20 seconds, and the strong light retention time and the weak light retention time were 10 seconds. The simulation data shown in table 2 were obtained according to the above simulation test conditions:
fig. 5 is drawn according to data in table 2, and fig. 5 is a schematic diagram showing a power change and maximum power tracking efficiency change curve of the static and dynamic MPPT disturbance observation and recognition method applied to a dynamic weather condition under a simulation condition. Referring to table 2 and fig. 5, it can be seen that: ideally, the theoretical voltage value is increased from 538.52V to 594.97V, that is, the theoretical Mppt voltage is increased, after the disturbance observation and identification method of the preferred embodiment is adopted, the actual photovoltaic operating voltage value is increased from 555.5V to 585.49V, and at the same time, even if the system power is increased, the disturbance reversal of the voltage is not the same direction, but the disturbance sign and the disturbance direction are continuously corrected, so that the photovoltaic equipment is finally operated near the maximum power point, the overall Mppt efficiency reaches 99.63, and compared with the efficiency of 82.54 under the traditional Mppt algorithm, the efficiency is greatly improved.
In another aspect of the present invention, a photovoltaic array power generation system designed based on the static and dynamic MPPT disturbance observation and identification method is provided, the system includes a photovoltaic array, such as a solar cell panel, which converts solar energy into electric energy, an ac converter is connected to an output end of the photovoltaic array, and a boost converter is used to realize maximum power tracking of the photovoltaic power generation system. And the MPPT controller or the MPPT module of the AC converter switch is connected with the output end of the photovoltaic array and used for driving the photovoltaic array. The MPPT module realizes the MPPT disturbance observation and identification method of the invention through a digital controller, generates PWM pulse, the pulse signal acts on the AC converter, and the converter outputs by controlling the switching time.
The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A photovoltaic static and dynamic MPPT disturbance observation and identification method is used for realizing maximum power output of a photovoltaic array under dynamic weather change, and is characterized by comprising the following steps:
a step S1 of configuring a policy identifier having at least two states, at least one of which corresponds to a static identification state and at least one of which corresponds to a dynamic identification state;
step S2, collecting photovoltaic power real-time values according to a preset period, and configuring the strategy identification according to photovoltaic power change;
when the policy identification is configured to be in a dynamic identification state, the method comprises the following steps:
step S3 of configuring disturbance identifiers, wherein the disturbance identifiers record the current disturbance state, the disturbance identifiers have at least two states, at least one of which corresponds to a default disturbance state, and at least one of which corresponds to an unconventional disturbance state, in which, in the default disturbance state, when the photovoltaic power real-time value is increased, the voltage disturbance direction is kept unchanged, and when the photovoltaic power real-time value is decreased, the voltage disturbance direction is reversed; in an unconventional disturbance state, when a photovoltaic power real-time value is increased, the voltage disturbance direction is reversed, and when the photovoltaic power real-time value is increased, the voltage disturbance direction is kept unchanged;
step S4 of configuring the disturbance flag to be in an unconventional disturbance state under normal state;
and S5, obtaining the power fluctuation size and trend in a period, configuring the current disturbance identifier according to the disturbance identifier and the disturbance direction of the previous period, and determining the current disturbance direction.
2. The method for observing and identifying the photovoltaic static and dynamic MPPT disturbances according to claim 1, wherein in the step S2, the process of configuring the policy identifier according to the photovoltaic power change specifically includes:
and configuring the strategy identification according to the fluctuation of the photovoltaic power real-time value.
3. The method for observing and identifying the photovoltaic static and dynamic MPPT disturbance according to claim 2, wherein the process of configuring the strategy identifier according to the fluctuation of the photovoltaic power real-time value specifically comprises:
collecting continuous M according to a preset period 1 A sub-photovoltaic power real-time value, at least two photovoltaic power change values are obtained, the times that the photovoltaic power change values are larger than a first preset power comparison value Pa are recorded, if the times reach a first preset value, the strategy identification is configured as a dynamic identification,
and/or the presence of a gas in the gas,
collecting continuous M according to a preset period 2 And acquiring at least two photovoltaic power change values, recording the times that the photovoltaic power change values are smaller than a first preset power comparison value Pa, and configuring the strategy identifier as a static identifier if the times reach a first preset value.
4. The method for observing and identifying MPPT disturbances according to claim 3, wherein in the process of configuring the strategy identification according to the fluctuation of the real-time value of the photovoltaic power,M 1 and M 2 Is a natural number of 3 or more, and M 2 Is greater than M 1 。
5. The method for observing and identifying the MPPT disturbance of the photovoltaic static and dynamic states as claimed in claim 3, wherein in step S5, the magnitude and the trend of the power fluctuation in a period are obtained, the current disturbance flag is configured according to the disturbance flag and the disturbance direction of the previous period, and the step of determining the current disturbance direction specifically comprises:
if the value of the current photovoltaic power real-time value reduction is larger than a first preset power comparison value Pa, configuring a disturbance identifier as a default disturbance state, and enabling the disturbance direction to be reversed;
if the absolute value of the change value of the current photovoltaic power real-time value is smaller than a first preset power comparison value Pa, judging a disturbance identifier of a previous period, if the disturbance identifier is in a default disturbance state, keeping the disturbance identifier and a disturbance direction unchanged, if the disturbance identifier is in an unconventional disturbance state, switching the disturbance identifier to be in the default disturbance state, and meanwhile reversing the disturbance direction;
if the rising value of the current photovoltaic power real-time value is larger than a first preset power comparison value Pa, acquiring the change trend of the photovoltaic power real-time value and the photovoltaic power change value in a preset period, and then configuring the disturbance identifier and the disturbance direction.
6. The method for observing and identifying photovoltaic static and dynamic MPPT disturbance according to claim 5, wherein in step S5, the magnitude and trend of power fluctuation in a period are obtained, the current disturbance identifier is configured according to the disturbance identifier of the previous period, and the step of determining the current disturbance direction specifically comprises:
s51, real-time value P of photovoltaic power for any moment n Obtaining the first n-1 photovoltaic power real-time value P ═ { P ═ P 1 、P 2 、P 3 …P n-2 、P n-1 、P n And obtaining a photovoltaic power change value delta P { [ delta ] P { ] 1 、△P 2 、△P 3 …△P n-2 、△P n-1 Step ofA step of;
s52, comparing the photovoltaic power change value delta P of the current period n-1 Comparing the value Pa with a first preset power, and if the value Delta P of the photovoltaic power change in the current period n-1 If the absolute value of (d) is smaller than the first preset comparison value Pa, go to step S53; if the photovoltaic power change value delta P of the current period n-1 Is negative, and Δ P n-1 If the absolute value of (d) is greater than the first preset comparison value Pa, go to step S54; if the photovoltaic power change value delta P of the current period n-1 If the comparison value is positive and greater than the first preset comparison value Pa, go to step S55;
s53, if the disturbance identifier of the previous period is in an unconventional disturbance state, setting the disturbance identifier as a default disturbance state and setting the disturbance direction as reverse disturbance, and if the disturbance identifier of the previous period is in the default disturbance state, maintaining the disturbance identifier and the disturbance direction unchanged;
s54, setting the disturbance identifier as a default disturbance state, and setting the disturbance direction as reverse disturbance;
and S55, acquiring the change trend of the photovoltaic power real-time value and the photovoltaic power change value in a preset period.
7. The photovoltaic static and dynamic MPPT disturbance observation and identification method according to claim 6, wherein in step S55, the step of obtaining the variation trend of the photovoltaic power real-time value and the photovoltaic power variation value in a preset period specifically comprises:
s551, obtaining M 1 Sub-photovoltaic power real-time value and M 2 Obtaining the change value of sub-photovoltaic power 1 If the change trend of the real-time value of the photovoltaic power is a discontinuous rising trend, the step S532 is executed, otherwise, the step S533 is executed;
s552, if M is judged 1 If the change trend of the sub-photovoltaic power real-time value is a discontinuous rising trend, setting the disturbance identifier to be in a default disturbance state, and keeping the disturbance direction unchanged;
s553, if M is judged 1 If the change trend of the real-time value of the sub-photovoltaic power is a continuous rising trend, the disturbance identifier of the last period is a default disturbance stateWhen the state is in, configuring a disturbance identifier as an unconventional disturbance state, and changing the disturbance direction; and when the disturbance mark of the previous period is in an unconventional disturbance state, judging according to the fluctuation trend of the photovoltaic power change value.
8. The method for observing and identifying the perturbation of the photovoltaic static and dynamic MPPT according to claim 7, wherein in step S553, the step of judging according to the fluctuation trend of the photovoltaic power variation value specifically comprises: at M 2 Setting a second preset power comparison value Pb in the sub-photovoltaic power variation value,
if Δ P n-1 -△P n-2 If the current disturbance identifier is greater than Pb, configuring the current disturbance identifier into a default disturbance state, and keeping the disturbance direction unchanged;
if Δ P n-2 -△P n-1 If the disturbance identifier is greater than Pb, keeping the disturbance identifier unchanged, and enabling the disturbance direction to be reversed;
if |. DELTA.P n-1 -△P n-2 If the absolute value is less than Pb, the current disturbance identifier is configured to be in a default disturbance state, and the disturbance direction is kept unchanged.
9. The photovoltaic static and dynamic MPPT disturbance observation and identification method according to any one of claims 1 to 8, characterized by comprising the following steps when the strategy identification is configured to be in a static identification state:
if the rising value of the current photovoltaic power real-time value is larger than a first preset power comparison value Pa, keeping the disturbance direction unchanged;
if the value of the current photovoltaic power real-time value reduction is larger than a first preset power comparison value Pa, enabling the disturbance direction to be reversed;
and if the absolute value of the change value of the current photovoltaic power real-time value is smaller than a first preset power comparison value Pa, keeping the disturbance direction unchanged.
10. A photovoltaic array power generation system with maximum power output by the photovoltaic static and dynamic MPPT disturbance observation and identification method as claimed in any one of claims 1 to 8, characterized by comprising a photovoltaic array, an AC converter connected to the output end of the photovoltaic array, an MPPT controller also connected to the output end of the photovoltaic array and used for driving the AC converter switch, and a load connected to the output end of the AC converter, wherein,
and the MPPT controller realizes the photovoltaic static and dynamic MPPT disturbance observation and identification method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210640185.7A CN114879806B (en) | 2022-06-07 | 2022-06-07 | Photovoltaic static and dynamic MPPT disturbance observation and identification method and photovoltaic array power generation system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210640185.7A CN114879806B (en) | 2022-06-07 | 2022-06-07 | Photovoltaic static and dynamic MPPT disturbance observation and identification method and photovoltaic array power generation system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114879806A true CN114879806A (en) | 2022-08-09 |
| CN114879806B CN114879806B (en) | 2024-02-20 |
Family
ID=82678927
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210640185.7A Active CN114879806B (en) | 2022-06-07 | 2022-06-07 | Photovoltaic static and dynamic MPPT disturbance observation and identification method and photovoltaic array power generation system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114879806B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117032385A (en) * | 2023-10-09 | 2023-11-10 | 威胜能源技术股份有限公司 | High-efficiency MPPT control method applied to BUCK topology |
| CN117055685A (en) * | 2023-10-12 | 2023-11-14 | 深圳鹏城新能科技有限公司 | MPPT optimization processing method and device, storage medium and electronic equipment |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102290840A (en) * | 2011-08-15 | 2011-12-21 | 北京航空航天大学 | Efficient photovoltaic charge control method for independent photovoltaic generating system |
| CN103529900A (en) * | 2013-11-04 | 2014-01-22 | 苏州大学 | MPPT calculation strategy and control method and photovoltaic array power generation system |
| KR101458363B1 (en) * | 2013-10-22 | 2014-11-06 | 공주대학교 산학협력단 | Maximum power point tracking method of photovoltaic system for tracking maximum power point under varying irradiance |
| CN104638668A (en) * | 2014-06-12 | 2015-05-20 | 华中科技大学 | Photovoltaic power generation grid connection control method and photovoltaic power generation grid connection control system |
| CN107491137A (en) * | 2017-09-29 | 2017-12-19 | 特变电工西安电气科技有限公司 | A kind of variable step constant speed drop volume limit power MPPT perturbation motion methods |
| CN108983864A (en) * | 2018-10-15 | 2018-12-11 | 西安许继电力电子技术有限公司 | A kind of tracking and its tracking device of maximum photovoltaic power point |
| CN109739292A (en) * | 2019-01-23 | 2019-05-10 | 济南大学 | Photovoltaic system MPPT obscures Auto-disturbance-rejection Control, controller and system |
| CN111198592A (en) * | 2018-11-19 | 2020-05-26 | 西安许继电力电子技术有限公司 | Photovoltaic maximum power point tracking method and device |
| CN111864795A (en) * | 2020-06-28 | 2020-10-30 | 天津大学 | MPPT trapezoidal voltage disturbance-based direct-current micro-grid island detection method |
-
2022
- 2022-06-07 CN CN202210640185.7A patent/CN114879806B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102290840A (en) * | 2011-08-15 | 2011-12-21 | 北京航空航天大学 | Efficient photovoltaic charge control method for independent photovoltaic generating system |
| KR101458363B1 (en) * | 2013-10-22 | 2014-11-06 | 공주대학교 산학협력단 | Maximum power point tracking method of photovoltaic system for tracking maximum power point under varying irradiance |
| CN103529900A (en) * | 2013-11-04 | 2014-01-22 | 苏州大学 | MPPT calculation strategy and control method and photovoltaic array power generation system |
| CN104638668A (en) * | 2014-06-12 | 2015-05-20 | 华中科技大学 | Photovoltaic power generation grid connection control method and photovoltaic power generation grid connection control system |
| CN107491137A (en) * | 2017-09-29 | 2017-12-19 | 特变电工西安电气科技有限公司 | A kind of variable step constant speed drop volume limit power MPPT perturbation motion methods |
| CN108983864A (en) * | 2018-10-15 | 2018-12-11 | 西安许继电力电子技术有限公司 | A kind of tracking and its tracking device of maximum photovoltaic power point |
| CN111198592A (en) * | 2018-11-19 | 2020-05-26 | 西安许继电力电子技术有限公司 | Photovoltaic maximum power point tracking method and device |
| CN109739292A (en) * | 2019-01-23 | 2019-05-10 | 济南大学 | Photovoltaic system MPPT obscures Auto-disturbance-rejection Control, controller and system |
| CN111864795A (en) * | 2020-06-28 | 2020-10-30 | 天津大学 | MPPT trapezoidal voltage disturbance-based direct-current micro-grid island detection method |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117032385A (en) * | 2023-10-09 | 2023-11-10 | 威胜能源技术股份有限公司 | High-efficiency MPPT control method applied to BUCK topology |
| CN117032385B (en) * | 2023-10-09 | 2023-12-22 | 威胜能源技术股份有限公司 | High-efficiency MPPT control method applied to BUCK topology |
| CN117055685A (en) * | 2023-10-12 | 2023-11-14 | 深圳鹏城新能科技有限公司 | MPPT optimization processing method and device, storage medium and electronic equipment |
| CN117055685B (en) * | 2023-10-12 | 2024-01-23 | 深圳鹏城新能科技有限公司 | MPPT optimization processing method and device, storage medium and electronic equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114879806B (en) | 2024-02-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114879806B (en) | Photovoltaic static and dynamic MPPT disturbance observation and identification method and photovoltaic array power generation system | |
| US9477247B2 (en) | Device and method for global maximum power point tracking | |
| CN103123514B (en) | Photovoltaic array multimodal maximum power point tracing method | |
| CN101630171B (en) | Segmentation self-adapting hill climbing method and system applied for tracing maximum power of photovoltaic cell | |
| US20210376790A1 (en) | Optimizer, photovoltaic power generation system, and iv curve scanning method for photovoltaic module | |
| US20130155739A1 (en) | Solar power generation system, control device used for solar power generation system, and control method and program for same | |
| CN109270982A (en) | A kind of photovoltaic maximum power tracking and controlling method | |
| CN103488238A (en) | Adaptive variable-step MPPT (maximum power point tracking) control method for coping with quick change of illumination intensity | |
| CN107918437A (en) | Progressive variable step maximum power point of photovoltaic array tracking and its system | |
| CN102043419A (en) | Maximum power point tracking (MPPT) method of currentless sensor | |
| Hu et al. | A novel MPPT control algorithm based on numerical calculation for PV generation systems | |
| CN202334369U (en) | Photovoltaic electrical energy optimizer | |
| Ai et al. | Design and implementation of a novel high-performance stand-alone photovoltaic LED lighting system | |
| KR20190036914A (en) | High Efficiency Photovoltaic System Using DC-DC Voltage Regulator | |
| CN106787866A (en) | The method that photovoltaic system extends maximum power tracing run time | |
| CN103412609A (en) | Output power control method of photovoltaic grid-connected inverter | |
| CN105159388B (en) | A kind of method of the MPPT maximum power point tracking in photovoltaic microgrid system | |
| CN109885123B (en) | Maximum power point tracking system and tracking method for photovoltaic module | |
| CN201450012U (en) | Segmented adaptive hill climbing method applied for tracking photovoltaic battery maximum power | |
| CN111367350A (en) | Photovoltaic maximum power tracking control method based on rolling small window | |
| US20220109400A1 (en) | Power backfeed control method, converter, and photovoltaic power generation system | |
| CN113359940B (en) | Maximum power point tracking method and system of photovoltaic array | |
| Itako et al. | A single sensor type MPPT control method for PV generation systems | |
| JP2015072667A (en) | Power supply device with maximum-power-point tracking means | |
| Nagvekar et al. | An improved GMPPT technique under partial shading conditions for PV array |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |