CN104040453A - Photovoltaic power generation system performing maximum power point tracking for each unit group - Google Patents
Photovoltaic power generation system performing maximum power point tracking for each unit group Download PDFInfo
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- CN104040453A CN104040453A CN201280062644.2A CN201280062644A CN104040453A CN 104040453 A CN104040453 A CN 104040453A CN 201280062644 A CN201280062644 A CN 201280062644A CN 104040453 A CN104040453 A CN 104040453A
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- 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
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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
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- 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
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Abstract
The present invention relates to a photovoltaic power generation system performing maximum power point tracking for each unit group which performs separate maximum power point tracking for each photovoltaic string, maximizes the inversion efficiency of an inverter by maintaining uniform input voltage from the inverter regardless of the difference between generated energy and generated voltage for each photovoltaic string, and thus improves the photovoltaic power generation efficiency. A photovoltaic power generation system performing maximum power point tracking for each unit group according to the present invention comprises: a plurality of photovoltaic strings formed by connecting a plurality of photovoltaic modules; a string optima for converting voltage generated from each of the plurality of photovoltaic strings into an output voltage of a uniform size, and controlling, for the conversion of the generated voltage, the maximum power point tracking for each photovoltaic string; and an inverter for converting the output voltage from the string optima into alternating voltage and supplying the power system therewith.
Description
Technical field
The present invention relates to a kind of the DC power being produced by solar cell is converted to AC power to supply the photovoltaic generating system of the AC power of being changed to electric system, more particularly, relate to a kind of photovoltaic generating system of each unit group being carried out to MPPT maximum power point tracking, it carries out independent MPPT maximum power point tracking to each photovoltaic string, and by no matter the difference between generated energy and the generating voltage of each photovoltaic string and keep equably the voltage input of inverter that the conversion efficiency of inverter is maximized, thereby improve photovoltaic efficiency.
Background technology
Because there is very little output for the solar cell of photovoltaic generation at present, so the photovoltaic module (PV module) by being connected in series the configuration of many solar cells is for effectively obtaining required power.This photovoltaic module can be with the power supply of operation that acts on street lamp or compact electronic device, still, due to generating voltage and energy little, photovoltaic module is difficult to generated output to be transferred to typical commercial power system.
For this reason, in the situation that photovoltaic module is intended to be connected to electric system and transmits generated output to it, photovoltaic array is by multiple photovoltaic modules being connected to a group or multiple this group being connected in parallel to configure, to produce its conversion and to transmit required voltage and power.Especially, be usually used in simply the DC power of generation being converted to AC power by the photovoltaic module series connection of formation group is connected to ganging up of configuration, and make power equipment, for example inverter standardization and simplification.
Fig. 1 is the figure of the configuration of schematically illustrated conventional photovoltaic power generation equipment.
With reference to Fig. 1, conventional photovoltaic power generation equipment comprises photovoltaic string 20 by being connected in series that multiple photovoltaic modules 10 configure and by a photovoltaic array 10A who configures that multiple this photovoltaic strings 20 are connected in parallel.
The output of photovoltaic array 10A is converted to AC power by inverter, and the AC power of conversion is supplied to electric system.
Because the output of solar cell is subject to such environmental effects widely, and its output valve change along with the variation of environmental factor very large, so this photovoltaic power generation equipment is difficult to obtain uniform output.Solar cell is subject to solar radiation maximum in environmental factor, and the temporary transient minimizing at the sunshine causing due to barrier, for example cloud is also the large reason that the output of solar cell reduces.In addition, by the entirety of environment temperature reduce the photovoltaic module causing temperature reduce be also solar cell output reduce reason.
The output minimizing of this solar cell and exporting change cause output to be converted to the Efficiency Decreasing of the inverter of AC power, so generating efficiency reduces greatly at the time point place that transmits power to electric system.
Keep the output of solar cell many as far as possible for stable, the method that development and application is generated electricity and controlled in various manners MPPT by controlling MPPT (MPPT maximum power point tracking).
Conventional MPPT is mainly by comparing the voltage of inverter input terminal and output terminal and utilizing fiducial value to regulate conversion ratio to carry out adjusting energy to carry out power tracking, and various algorithms are applied to the adjusting of MPPT for this conversion ratio.
But although have advantages of and simplify in the situation that simply controlling and be easy to control control system for the conventional control algolithm of power tracking, it is difficult to the situation of corresponding large rapidly exporting change, and is difficult to control corresponding to environmental factor.
In addition, for example, although complex control algorithm, purify to control and have advantages of and can improve generating efficiency, it is because the high-performance of control circuit and the increase of algorithm complex are not easy application.
Summary of the invention
Technical matters
An object of the present invention is to provide a kind of photovoltaic generating system of each unit group being carried out to MPPT maximum power point tracking, it carries out independent MPPT maximum power point tracking to each photovoltaic string, and keep equably by the difference regardless of between generated energy and the generating voltage of each photovoltaic string to the voltage input of inverter, the conversion efficiency of inverter being maximized, thereby improve photovoltaic efficiency.
Another object of the present invention is to provide a kind of photovoltaic generating system of each unit group being carried out to MPPT maximum power point tracking, and it can, by environmental factor being applied to simple control method to carry out simply power tracking, improve maximum generation efficiency.
A further object of the present invention is to provide a kind of photovoltaic generating system of each unit group being carried out to MPPT maximum power point tracking, it can be stored and keep voltage and current value according to environmental factor and power tracking, and can improve tracking response speed by the estimation of expecting via this voltage and current value in supervise, thereby improve generating efficiency.
Solution
Object of the present invention can be by providing a kind of photovoltaic generating system to each unit group execution MPPT maximum power point tracking to realize, described system comprises the multiple photovoltaic strings by connecting multiple photovoltaic module configurations, it is the output voltage with formed objects by the voltage transitions of the each generation by multiple photovoltaic strings, and each photovoltaic string is carried out to the string optimizer of MPPT maximum power point tracking control with conversion power generation voltage, with for being converted to alternating voltage the alternating voltage of conversion is fed to the inverter of electric system from the output voltage of string optimizer.
String optimizer can comprise and be connected to each in multiple photovoltaic strings, generating voltage be converted to output voltage and carry out the string control device of MPPT maximum power point tracking control; Generation comprises the sensing unit of the sensing value of environmental factor, generating voltage and output voltage; With utilize sensing value to produce for going here and there the control module of each power tracking control signal of control device.
Environmental factor can comprise at least one in lip-deep temperature, air quantity, wind speed and the humidity of temperature, photovoltaic module of the each installation region in sunshine, photovoltaic module.
Output voltage can be variable.
String control device can comprise for increasing or reduce the converter from each input voltage of photovoltaic string, be connected to the fuse between photovoltaic string and converter, be connected to the isolating switch of the output terminal of converter, and produce the MPPT controller for increasing or reduce the control signal of the voltage of converter.
Control module can comprise: following range computing unit, and it is for calculating the following range value that is included in the curtage scope of wherein carrying out MPPT maximum power point tracking by sensing value; Control signal generation unit, it produces MPPT maximum power point tracking control signal for following range value, input voltage and output voltage by from following range computing unit; With follow the tracks of history storage unit, it is for by mating following range value and sensing value each to store following range value.
Following range computing unit can be divided into multiple time periods by the photovoltaic module generating dutation of a day, and calculates about the each basic following range in multiple time periods.
Following range computing unit can be by the desired extent of the environmental factor sensing value reflection energy variation in basic following range, to calculate following range.
In the time of the maximum tracking range of generating voltage and the temporary transient overtime section of output voltage place expection, following range computing unit can not carried out power tracking to the excess quantity of generating voltage and output voltage.
Each in photovoltaic string can be fixed or following-up type photovoltaic module.
String optimizer and inverter can configure each other integratedly.
Beneficial effect
Photovoltaic generating system to each unit group execution MPPT maximum power point tracking according to the present invention can be carried out independent MPPT maximum power point tracking to each photovoltaic string, and keep equably by the difference regardless of between generated energy and the generating voltage of each photovoltaic string to the voltage input of inverter, the conversion efficiency of inverter being maximized, thereby improve photovoltaic efficiency.
In addition, the photovoltaic generating system to each unit group execution MPPT maximum power point tracking according to the present invention can improve maximum generation efficiency to carry out simply power tracking by environmental factor being applied to simple control method.
In addition, the photovoltaic generating system that each unit group is carried out to MPPT maximum power point tracking according to the present invention can be stored and keep voltage and current value according to environmental factor and power tracking, and can improve tracking response speed by the estimation of expecting via this voltage and current value in supervise, thereby improve generating efficiency.
Brief description of the drawings
Fig. 1 is the figure of the configuration of schematically illustrated conventional photovoltaic power generation equipment.
Fig. 2 is the figure of the configuration of schematically illustrated photovoltaic generating system according to an embodiment of the invention.
Fig. 3 is the figure that the configuration of string optimizer is shown particularly.
Fig. 4 is the figure that the configuration of the control module of string optimizer is shown particularly.
Fig. 5 is the schematic diagram calculating according to the following range of the temperature of environmental factor and illumination for explaining.
Fig. 6 is for explaining according to the schematic diagram of the power tracking of time.
Fig. 7 is for explaining the storage of following the tracks of historical information and the schematic diagram that uses the method for this storage.
Fig. 8 is the figure that the configuration of photovoltaic generating system is according to another embodiment of the invention shown.
Embodiment
Can at length mention now exemplary of the present invention, the example describes in the accompanying drawings.In disclosure full text, in each figure of the present invention and embodiment, identical Reference numeral represents identical part.If determine that the detailed description of known correlation technique may unnecessarily make purport of the present invention unclear in it is described, and can omit its detailed description.Accompanying drawing needn't equal proportion, and in some cases, ratio may be exaggerated, to be clearly shown that the feature of embodiment.But those of ordinary skill in the art can easily understand details.
Fig. 2 is the figure of the configuration of schematically illustrated photovoltaic generating system according to an embodiment of the invention.
With reference to Fig. 2, photovoltaic generating system according to the present invention comprises photovoltaic array 100, string optimizer 200 and inverter 300.String optimizer 200 comprises control module 210 and string control device 220.
Photovoltaic array 100 is fed to string optimizer 200 by solar power generation and by generated output.For this reason, photovoltaic array 100 comprises multiple photovoltaic strings 120, the each string control device 220 being associated in string optimizer 200 that is separately connected in photovoltaic string 120.
Photovoltaic string 120 configures by being connected in series multiple photovoltaic modules 110.Photovoltaic string 120 configures by being connected in series multiple photovoltaic modules 110, to obtain the generating voltage that is equal to or greater than certain level.The quantity that forms the photovoltaic module 110 of photovoltaic string 120 can change according to the string input voltage of optimizer 200 and the input voltage of inverter 300.
It is the voltage matching with the input voltage of inverter 300 that string optimizer 200 is changed the power transfer of being supplied by each photovoltaic string 120 by DC-DC.For this reason, string optimizer 200 is carried out DC-DC conversion by MPPT maximum power point tracking control, and is reflected in the energy variation in MPPT maximum power point tracking control period environmental factor.
For this reason, string optimizer 200 comprises: the string control device 220 of the voltage of the generated output of being supplied by each photovoltaic string 120 being carried out to DC-DC conversion and MPPT maximum power point tracking; With control module 210, this control module 210 is by environmental factor and be input to the input voltage of string control device 220 and be set to sensing value from the output voltage exported of string control device 220 and produce the control signal for controlling string control device 220.
Control module 210 produces the each control signal for controlling separately multiple string control device 220.Especially, control module 210 is carried out power tracking by the output voltage that is input to the each input voltage in string control device 220 and the each output from string control device 220 to each string, and the control signal of generation is transferred to the string control device 220 being associated.Especially, control module 210 is carried out power tracking according to the environmental information of transmitting from sensor 130.
Particularly, control module 210 is followed the tracks of maximum power point by apply different following ranges according to environmental information, and producing thus control signal this control signal is transferred to string control device 220, described environmental information is for example the sunshine of the installed position of photovoltaic module 110 or photovoltaic string 120, the temperature of installed position, the temperature and time of panel.Can this control method be described in more detail with reference to following other accompanying drawing.
The DC voltage of being supplied by photovoltaic string 120 is converted to input direct voltage by string control device 220, and the input direct voltage of conversion is fed to inverter 301.This conversion is carried out under the control of control module 210.
Especially, string control device 220 is transferred to control module 210 by be input to the output voltage values that outputs to inverter the input voltage value of string control device 220 and conversion from photovoltaic string 120.Can be with reference to the following drawings configuration and operation of description string control device 220 in more detail.
Inverter 300 receives the generated output with even input voltage by string optimizer 200, with by DC-AC changing of transformation generated output, then the power of conversion is fed to electric system 400.The input end of inverter 300 is parallel-connected to the output terminal of string control device 220.
Fig. 3 is the figure that the configuration of string optimizer is shown particularly.
With reference to Fig. 3, string optimizer 200 is by fuse 211 relay protections and connection between each string control device 220 and each photovoltaic string 120.Fuse 211 is used for by automatically cut off holding circuit in the time that superpotential or excess current occur photovoltaic string 120.In addition, isolating switch 212 is installed to the output terminal of string optimizer 200, and is used for, at photovoltaic string 120 or string optimizer 200, the connection between inverter 300 and string optimizer 200 occurs to disconnect when abnormal.
Each comprising in string control device 220: DC-DC converter 222, this converter is connected to the photovoltaic string 120 being associated by fuse 211, taking the input voltage as inverter 300 by the voltage transitions of the power of being supplied by photovoltaic string 120; With MPPT controller 221, this MPPT controller control converter 222, makes converter 222 according to the control signal Maximum Power Output of control module 210.For this reason, the control module 21 of string control device is connected to the MPPT controller 221 of each string control device 220.
The output voltage that is input to the each input voltage in string control device 220 and the each output from string control device 220 can be measured by MPPT controller 221, to be transferred to control module 210, or control module 210 can directly receive from the magnitude of voltage that is installed to the input end of each string control device 220 and the voltage-level detector of output terminal.But the present invention is not limited to this.
Fig. 4 is the figure that the configuration of the control module of string optimizer is shown particularly.
With reference to Fig. 4, control module comprises sensing unit 211, following range computing unit 310, follows the tracks of history storage unit 320 and control signal generation unit 330.
Sensing unit 211 sensings are for generation of the information of control signal, and by this communication to following range computing unit 310.For this reason, sensing unit 211 comprises input voltage detecting unit 301, output voltage detecting unit 302 and sensor 130.Input voltage detecting unit 301 detects the voltage of the power that is input to string optimizer 200.Output voltage detecting unit 302 detects the voltage of the power of exporting from string optimizer 200.Each input and output voltage in this input voltage detecting unit 301 and the real-time sensing string control device 220 of output voltage detecting unit 302, and by the input and output voltage transmission sensing to following range computing unit 310.Sensor 130 sensings affect the environmental factor of photovoltaic array 100, and the result sensing is transferred to following range computing unit 310.The environmental factor that sensor 130 senses can comprise temperature and humidity in the installation region that is irradiated to the amount of the sunshine on photovoltaic array 100 and illumination, photovoltaic array 100 and the lip-deep temperature of each photovoltaic module 110.In addition, also can measure all factors that can cause energy variation.
Following range computing unit 310 is chosen in the voltage and current scope of wherein carrying out maximal power tracing according to the sensing result of sensing unit 211, and the value range of selection is transferred to control signal generation unit 330.That is to say, following range computing unit 310 is according to from the input and output voltage of sensing unit 211 with grasped the size of the power of being supplied by photovoltaic string 120 by the information of sensor 130 sensings, and calculates according to current state of weather the voltage and current scope that photovoltaic module 110 can generate electricity substantially therein.
Especially, in this computation process, before following range computing unit 310 reflection according to the visual information in the information of operation input or accumulation and date or season information, to calculate following range.Following range computing unit 310 by input and output voltage transmission to control signal generation unit 330, and by the following range communication calculating to control signal generation unit 330 with follow the tracks of history storage unit 320.For each photovoltaic string 120 produces the following range being produced by following range computing unit 310 individually.
Can following range computing unit 310 and the operation of string optimizer 200 with following range computing unit 310 be described in more detail with reference to Fig. 5 and accompanying drawing afterwards.
Follow the tracks of history storage unit 320 and store the following range information transmitted from following range computing unit 310 and the environmental factor information by sensing unit 211 sensings simultaneously, and answer the request of following range computing unit 310 that canned data is provided.Especially, follow the tracks of the variation that history storage unit 320 recorded and kept input voltage, output voltage and peak power according to the environmental factor of the time zone on each date and each season or state of weather.
Control signal generation unit 330 utilizes the input and output magnitude of voltage transmitting by following range computing unit 310 and the following range value of being calculated by following range computing unit 310 to produce the control signal of the power conversion rate for controlling MPPT controller 222, and this control signal is transferred to the MPPT controller 222 being associated.
Fig. 5 is the schematic diagram calculating according to the following range of the temperature of environmental factor and illumination for explaining.
With reference to Fig. 5, (a) be the figure illustrating according to the output voltage/electric current relation of the photovoltaic string of temperature, be (b) figure illustrating according to the output voltage/electric current relation of the photovoltaic string of illumination.
In figure (a), when at the identical state decline low temperature of illumination, the voltage swing being produced by photovoltaic string is less, and therefore generated output reduces conventionally.Fig. 5 (a) shows the figure when the temperature of the C voltage/current during lower than the temperature of A.In this case, even have while being worth more uniformly when electric current, it is less that voltage swing also can become, and therefore peak power also can become less.
Similarly, in figure (b), when change illumination under the identical state of other condition time, output voltage values V (Va is to Vc) and output current value I (Ia is to Ic) is as directed changes to C' via A', therefore changes peak power.
Therefore, string optimizer 200 of the present invention, particularly following range computing unit 310 is according to being chosen in by the environmental factor of sensing unit 211 sensings the voltage and current scope that wherein forms maximum power point, and the following range value calculating is transferred to control signal generation unit 330, make within MPPT maximum power point tracking can be controlled in the voltage and current scope of selection.Therefore, MPPT controller 221 is carried out power tracking in the voltage and current value that can carry out as quickly as possible maximal power tracing, and can improve thus the generating efficiency of solar cell.
Particularly, temperature, unless particularly the lip-deep temperature of photovoltaic module has by other such environmental effects otherwise the performance that slowly changes according to the time.But the lip-deep temperature of photovoltaic module may reduce rapidly due to the wind in winter.That is to say, in Fig. 5 (a), form maximum power point in scope 1 (P1) after, due to temperature fast reducing, can in scope 2 (P2), form maximum power point.In this case, conventional control device is carried out maximal power tracing until change and reach 2 (P2) corresponding to the voltage and current of scope 1 (P1).Therefore, this can expend the long period.Especially, because disturb in maximal power tracing in the time that then the temporary transient reduction of temperature recovers rapidly, so accurate tracking expends the plenty of time.
But, because the present invention selects following range according to temperature variation and carry out power tracking within the scope of this, follow the tracks of and make power dissipation to minimize so can carry out rapidly.
Fig. 6 is for explaining according to the schematic diagram of the power tracking of time.
Fig. 6 (a) is the view that the generating dutation classification to each time zone is shown, Fig. 6 (b) illustrates that the output voltage of photovoltaic string and output current are according to the figure of the variation of time period.
With reference to Fig. 6, in photovoltaic generation, most important factor is whether to have light and the light quantity for generating electricity.Light quantity changes according to time zone, instead of keeps from sun to sun evenly.Especially, even under the maximum amount before and after high noon in winter, the situation that also is often difficult to farthest generate electricity.Especially, promptly occur to change sunshine when early morning in winter and dusk.In the time that time zone is advanced in a clockwise direction in figure (a), in voltage/current figure (b), output changes along increasing direction x1.When time zone through figure (a) in during as the b5 of the maximum output point of time and b6 period, in figure (b), output changes along reducing direction y1.
In the situation that simply carrying out power tracking by this time zone and mid-season output and input voltage, even if be also difficult to produce peak power in the time carrying out maximal power tracing.Especially, in the situation that weather and temperature quite promptly change, as in winter or rainy season, be more difficult to carry out maximal power tracing, thereby cause energy loss.
Therefore, the generating dutation classification of the present invention to each time zone, makes to estimate maximal power tracing scope (B1 is to B10), and for each scope selection following range is to produce the control signal for controlling MPPT controller 221.
Particularly, suppose in figure (a), the time zone that can generate electricity winter to be classified, change and be difficult to carry out rapidly maximal power tracing rapidly owing to impinging upon day in the first period b1, the second period b2 and the 9th period b9 and the tenth period b10.But, calculating following range and calculating thus the voltage and current scope of this time by comparing sunshine and predetermined section, and in the case of carrying out in the following range calculating power tracking, can improve speed and the efficiency of MPPT maximum power point tracking.Especially, the present invention is that each time zone is selected basic following range, by recalculating following range according to the generating rate of descent of temperature with according to the basic following range that the generating rate of descent at sunshine is applied to selection, thereby carries out MPPT maximum power point tracking.Therefore, can simply environmental factor be applied to power points following range.
In addition, together with the peak power dot information of the state of weather, energy of the computing information of generating rate of descent in the time measuring in the time forming, store.Therefore, this information can be used as master data, while determining similar environment, can carry out rapidly MPPT maximum power point tracking after making.
That is to say, in the time that output voltage and output current change according to time zone in as figure (b), in the following range of the maximum power point of MPPT maximum power point tracking before in approaching corresponding to the following range of period of the time zone that is associated, carry out, instead of maximum power point before changing from output voltage and output current is carried out.Therefore,, compared with correlation technique, by reducing the required time of MPPT maximum power point tracking, can make generating efficiency remain on high degree.
In the pursuit gain situation changing for each time zone in having as figure (b), even in the time of temporary transient generation temperature variation and Changes in weather, also can, by generating efficiency reduction and following range change application according to Changes in weather are arrived to the pursuit gain changing for each time zone, carry out rapidly MPPT maximum power point tracking.
Fig. 7 is the schematic diagram of following the tracks of historical information storage and using the method for this storage for explaining.
With reference to Fig. 7, photovoltaic string 120 can be expressed as the output map of the special time shown in Fig. 7 (a).In this case, maximum output tracking scope is the P11 on V-I figure.In the time that environmental factor is constant, following range computing unit 310 is selected following range, make near the power tracking execution point of voltage Vp and electric current I p, and control signal generation unit 330 reflects the input and output voltage of converter in the following range of selecting, and carry out power tracking, make photovoltaic string 120 be operating as generation peak power.In addition, follow the tracks of history storage unit 330 and store voltage and current value, environment temperature, panel temperature, sunshine, time, the wind speed and direction information in MPPT maximum power point tracking scope under execution MPPT maximum power point tracking condition, and in the time carrying out power tracking afterwards under conditions of similarity, canned data is with acting on the information of determining following range.
While variation in environmental factor is being carried out as the process of the maximal power tracing in figure (a), may change for the figure of maximal power tracing itself.For example, while variation when temperature with in day impinging upon among a small circle, can carry out MPPT maximum power point tracking by figure (a).But while variation when temperature with in day impinging upon on a large scale, the V-I figure of MPPT maximum power point tracking also has the value that large degree changes.
In this case, carry out if maximum output point is followed the tracks of by the feedback of input and output voltage as above, expend for a long time, and may cause the Efficiency Decreasing of electricity generation system, until carry out stable tracking and maximum generation.
Therefore, control photovoltaic generating system of the present invention, makes to carry out rapidly MPPT maximum power point tracking by add environmental factor in these factors.
This state is shown in figure (b).Figure (b) be by figure (a) by carry out therein power tracking photovoltaic string 120 temperature and change the V-I producing sunshine and scheme.In this case, maximum power point changes to P12 scope from P11 scope.Also can be by the variation of conventional input and output voltage-tracing V-I figure.But, by the variation of applied environment factors vary, output rating variation or V-I figure in the present invention, can expect and react more rapidly.
For example, in the time that sunshine and temperature change in as figure (b), can typically only reflect that the temperature of sunshine and variation is to select following range.But, when reflect environmental factor in the following range as in the present invention time, can be by follow the tracks of the variation of V-I figure according to the temperature variation of environment temperature prediction panel.In addition,, even in the time heating photovoltaic module by sunshine winter, the temperature of photovoltaic panel also changes according to the temperature of the installed position of solar cell and wind speed.Therefore, can directly affect generating.In this case, can be by determining similar factor and apply determined because usually pre-estimating the following range of expection by the trace information before storage in tracking history storage unit 330.In the time of the input and output change in voltage of photovoltaic string 120, can find simply the voltage and current scope for MPPT maximum power point tracking by the following range that input and output magnitude of voltage is applied to expection.
In addition, as described in Fig. 6, generating dutation is categorized as multiple periods by string optimizer 200 of the present invention, and be reflected in environmental factor in the representative following range of each time period and the input and output voltage of converter, to carry out power tracking.
According to the tracking of the basic following range of each time period of use, for example, when the generating dutation region of by environmental factor, accumulating at present when generating electricity and temperature are carried out, can predict season and weather conditions.Therefore, can predict simply and follow the tracks of the variation of following range.In addition, in the time of environmental factor, for example winter impact generating, the tracking of the period by each time zone can be conducive to carry out MPPT maximum power point tracking.
In MPPT maximum power point tracking, carry out and follow the tracks of by continually varying voltage or electric current.In this case, can cause to a great extent the temporary transient variation of voltage or electric current.When carry out tracking according to the variation of voltage or electric current in this state time, the temporary transient tracking Efficiency Decreasing changing after removing.But, when by chronological classification with consider that while limiting following range corresponding to the seasonal factor of the time of being associated, the large voltage or the curent change that do not produce according to the short time are carried out tracking.Therefore, can prevent that generating efficiency from reducing.In addition, by being increase or reduce and input and output voltage to its applied environment factor and converter according to the period predicted voltage of each time zone or electric current, can determine simply tracking direction execution MPPT maximum power point tracking rapidly.In addition, by means of according to the time period with according to aligning and the access of the environmental factor of the period in season of time period, and select following range with this aligning and access, can utilize uncomplicated algorithm compared with correlation technique to carry out rapidly tracking.
Fig. 8 is the figure that the configuration of photovoltaic generating system is according to another embodiment of the invention shown.
With reference to Fig. 8, in photovoltaic generating system according to another embodiment of the invention, inverter 300 is configured by string optimizer 200 and inverter section 390.
That is to say, the difference of photovoltaic generating system according to another embodiment of the invention and the embodiment of above-mentioned Fig. 2 is, string optimizer 200 and inverter 300 are configured to an element.Other configuration and operation and above-mentioned embodiment are similar.Therefore, repeat no more independent configuration and operation.
Can be apparent to those skilled in the art, in the situation that not departing from the spirit or scope of the present invention, can make various modifications and variations to the present invention.Therefore, the present invention is intended to contain modifications and variations of the present invention, as long as they are in the scope of claims and equivalent thereof.
Industrial applicibility
Compared with each array element being carried out to the photovoltaic generating system of MPPT maximum power point tracking, the present invention can be by carrying out to each unit of the solar cell being connected in series the generation that MPPT maximum power point tracking improves generating efficiency and increases energy.In addition, the present invention can be by being converted to AC power by the peak power that inverter produces each photovoltaic string and being the work efficiency that identical voltage improves inverter by the voltage transitions of the each photovoltaic string that is input to inverter.
In addition, the present invention can reuse existing system by the inverter of replacing existing photovoltaic generating system with string optimizer of the present invention and inverter, thereby makes existing photovoltaic generating system can be reconfigured for high efficiency systems.
Claims (11)
1. a photovoltaic generating system of each unit group being carried out to MPPT maximum power point tracking, comprising:
By connecting multiple photovoltaic strings of multiple photovoltaic module configurations;
String optimizer, its voltage transitions by the each generation by described multiple photovoltaic strings is the output voltage with formed objects, and each photovoltaic string is carried out to MPPT maximum power point tracking control with conversion power generation voltage; With
Inverter, it is for the described output voltage from described string optimizer is converted to alternating voltage, to supply the alternating voltage of being changed to electric system.
2. photovoltaic generating system according to claim 1, wherein, described string optimizer comprises:
String control device, it is connected to each in described multiple photovoltaic string, described generating voltage be converted to described output voltage and carry out MPPT maximum power point tracking control;
Sensing unit, its generation comprises the sensing value of environmental factor, described generating voltage and described output voltage; With
Control module, it utilizes described sensing value to produce the each power tracking control signal for described string control device.
3. photovoltaic generating system according to claim 2, wherein, described environmental factor comprises at least one in lip-deep temperature, air quantity, wind speed and the humidity of the temperature in the each installation region in sunshine, described photovoltaic module, described photovoltaic module.
4. photovoltaic generating system according to claim 3, wherein, described output voltage is variable.
5. photovoltaic generating system according to claim 4, wherein, described string control device comprises:
For increasing or reduce the converter from each input voltage of described photovoltaic string;
Be connected to the fuse between described photovoltaic string and described converter;
Be connected to the isolating switch of the output terminal of described converter; With
Produce the MPPT controller for increasing or reduce the control signal of the voltage of described converter.
6. photovoltaic generating system according to claim 5, wherein, described control module comprises:
Following range computing unit, it is for calculating the following range value that is included in the curtage scope of wherein carrying out MPPT maximum power point tracking by described sensing value;
Control signal generation unit, it is for by producing MPPT maximum power point tracking control signal from the described following range value of described following range computing unit, described input voltage and described output voltage; With
Follow the tracks of history storage unit, it is for by mating described following range value and described sensing value each to store described following range value.
7. photovoltaic generating system according to claim 6, wherein, the described photovoltaic module generating dutation of a day is divided into multiple time periods by described following range computing unit, and calculate about the each basic following range in described multiple time periods.
8. photovoltaic generating system according to claim 7, wherein, described following range computing unit is by the desired extent of the environmental factor sensing value reflection energy variation in described basic following range, to calculate described following range.
9. photovoltaic generating system according to claim 6, wherein, in the time of the maximum tracking range of described generating voltage and the temporary transient overtime section of described output voltage place expection, described following range computing unit is not carried out power tracking to the excess quantity of described generating voltage and described output voltage.
10. photovoltaic generating system according to claim 8, wherein, each in described photovoltaic string is fixed or following-up type photovoltaic module.
11. photovoltaic generating systems according to claim 1, wherein, described string optimizer and described inverter be configuration integratedly each other.
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2011-0137355 | 2011-12-19 | ||
| KR1020110137355A KR101128386B1 (en) | 2011-12-19 | 2011-12-19 | Photovoltaic power generation system |
| KR10-2011-0141511 | 2011-12-23 | ||
| KR1020110141510A KR101135386B1 (en) | 2011-12-23 | 2011-12-23 | Photovoltaic power generation system perform the maximum power point tracking about the unit group |
| KR1020110141511A KR101132323B1 (en) | 2011-12-23 | 2011-12-23 | Photovoltaic power generation system perform the maximum power point tracking about the unit group |
| KR10-2011-0141510 | 2011-12-23 | ||
| PCT/KR2012/005901 WO2013094838A1 (en) | 2011-12-19 | 2012-07-24 | Photovoltaic power generation system performing maximum power point tracking for each unit group |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104040453A true CN104040453A (en) | 2014-09-10 |
| CN104040453B CN104040453B (en) | 2016-02-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201280062644.2A Expired - Fee Related CN104040453B (en) | 2011-12-19 | 2012-07-24 | Each unit group is performed to the photovoltaic generating system of MPPT maximum power point tracking |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP2015502621A (en) |
| CN (1) | CN104040453B (en) |
| WO (1) | WO2013094838A1 (en) |
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| CN108336753A (en) * | 2017-01-20 | 2018-07-27 | 丰郅(上海)新能源科技有限公司 | Realize the maximized photovoltaic generating system of output power and method |
| CN112925377A (en) * | 2021-02-01 | 2021-06-08 | 浙江晶科能源有限公司 | Photovoltaic system and maximum power tracking method thereof |
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| KR101543768B1 (en) * | 2014-04-02 | 2015-08-11 | 동양이엔피 주식회사 | 3-input photovoltaic inverter apparatus |
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| TWI697791B (en) * | 2019-03-20 | 2020-07-01 | 龍華科技大學 | Solar cell maximum power tracking method under shading |
| CN112782495A (en) * | 2019-11-06 | 2021-05-11 | 成都鼎桥通信技术有限公司 | String abnormity identification method for photovoltaic power station |
| CN112462176B (en) * | 2020-11-13 | 2022-06-28 | 丰郅(上海)新能源科技有限公司 | Device and method for supporting detection of photovoltaic system direct current arc fault |
| CN112817341B (en) * | 2021-02-03 | 2023-09-29 | 阳光电源股份有限公司 | Photovoltaic tracking support control method, photovoltaic tracking controller and photovoltaic tracking system |
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| JP2015502621A (en) | 2015-01-22 |
| CN104040453B (en) | 2016-02-24 |
| WO2013094838A1 (en) | 2013-06-27 |
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