CN108512415A - A kind of voltage-dropping type photovoltaic optimization system control method being simple and efficient - Google Patents

A kind of voltage-dropping type photovoltaic optimization system control method being simple and efficient Download PDF

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Publication number
CN108512415A
CN108512415A CN201711282374.7A CN201711282374A CN108512415A CN 108512415 A CN108512415 A CN 108512415A CN 201711282374 A CN201711282374 A CN 201711282374A CN 108512415 A CN108512415 A CN 108512415A
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China
Prior art keywords
mode
mppt
control method
straight
voltage
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CN201711282374.7A
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Inventor
孟令孔
揭东华
宋朝盛
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Shanghai Salt Mdt Infotech Ltd
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Shanghai Salt Mdt Infotech Ltd
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Priority to CN201711282374.7A priority Critical patent/CN108512415A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02J3/385—
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
    • H02S40/30—Electrical components
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The present invention relates to a kind of voltage-dropping type photovoltaic optimization system control methods being simple and efficient, including timer synchronization to start control method, timer period interrupt control method and MPPT mode and jump to straight-through modal control method.The invention enables each components of system to realize maximum power point tracking, while not will produce additional switching loss again（There is no the component optimizer of mismatch that can all be operated in pass-through state）；Communication system is not needed, you can realize that system MPPT controls and mode redirect, reduce system cost, improve reliability.

Description

A kind of voltage-dropping type photovoltaic optimization system control method being simple and efficient
Technical field
The invention belongs to new forms of energy control technology field, be related to the maximum power point of grid-connected/off-network electricity generation system with Track technology, in particular to a kind of voltage-dropping type photovoltaic optimization system control method being simple and efficient.
Background technology
Traditional grid-connected/off-network electricity generation system, MPPT maximum power point tracking is done by inverter（MPPT）, due to inverter Input termination be a string formation either the array of several groups connection in series-parallel composition therefore inverter can only to string formation or array into Row MPPT maximum power point tracking；When for each inter-module there are when mismatch, the PV curves of system will present two features in string formation and array： 1）PV curves are no longer monotonic increase to the left at maximum power point from right end open-circuit voltage；2）The maximum work of PV curves Rate point is less than the actual maximum power point of system（Each component realizes MPPT）, as shown in Figure 1；
As it can be seen that the photovoltaic optimization system of installation photovoltaic optimizer can effectively retrieve the loss caused by mismatch, system hair is improved Electricity.
The MPPT controls of photovoltaic optimization system at present, especially MPPT mode redirect scheme with straight-through mode, mainly have Two kinds：
Scheme one：Every optimizer independently carries out MPPT maximum power point tracking（MPPT）Control, need not establish communication with each other, but It need to be in MPPT mode always（MPPT mode refers to the state that optimizer tracks maximum power point in dynamic regulation always, that is, is begun It is in HF switch state eventually）, i.e., without straight-through operation mode（Straight-through mode refers to optimizer upper tube constant conduction, that is, is inputted Output is straight-through, is lost without HF switch）；Optimizer need always be in MPPT mode, be because once by MPPT principles into Enter pass-through state, due to mutual coupling restriction effect, can make optimizer that can not return to MPPT states；This control program is excellent Point is every optimizer independent control, at low cost independent of communication, and reliability is high；The disadvantage is that being in HF switch always State, switching loss are relatively high；
Scheme two：In view of there was only mismatch component in system（Damage, shade, aging etc.）Optimizer need to be operated in MPPT Mode（HF switch, the state of duty ratio constantly regulate）, the optimizer maintenance of the component of mismatch is not straight-through（It is logical to switch pipe range State）, can realize that system effectiveness maximizes to avoid additional switching loss in this way；Control method is：By one in system Platform data collector acquires the data of every optimizer, according to the voltage of acquisition, current data, confirms mismatch component, and make it Optimizer is operated in MPPT mode, without the component of mismatch, is operated in straight-through mode；The advantages of scheme two, is, without mismatch Component operation in straight-through mode, avoid additional switching loss, realize system effectiveness maximization；The disadvantage is that depending on System communication, once communication failure or data packetloss, then cannot achieve component level MPPT controls, on the other hand, communication system Also increase system cost.
Component level MPPT maximum power point tracking may be implemented in photovoltaic optimization system（MPPT）, caused by effectively retrieving mismatch problems Loss improves system generated energy, but separate control solution makes every optimizer all be in HF switch state always, increases Switching loss；System control scheme dependent on communication increases system cost, and under communication failure and data packet drop, Component level MPPT controls are cannot achieve, system reliability is relatively low.
Therefore, the photovoltaic optimization system control method being simple and efficient just becomes active demand.
Invention content
For the deficiency of the existing two kinds of control methods of photovoltaic optimization system, present invention aims at provide a kind of simple height The photovoltaic optimization system control method of effect.Photovoltaic optimization system efficiency is set to maximize, cost minimization is reliable and stable.In order to reach To above-mentioned purpose, the technical solution adopted by the present invention is design,
In order to achieve the above object, the present invention adopts the following technical scheme that：
Start control method including timer synchronization, periodically to execute, step is：
It first determines whether timer has been turned on, terminates if starting；
If not actuated, have：Optimizer is started with straight-through mode, and ensures to may be incorporated into inverter work；Then inspection optimization device Electric current Io, the current threshold I of setting timer startupinvon, then have：
If Io≥Iinvon, then start timer, and terminate；
If Io<Iinvon, then terminate.
Wherein, including timer period interrupt control method, step are：
First determine whether work at present mode is MPPT mode, if so, maintaining MPPT mode；
If it is not, then leading directly to mode jumps to MPPT mode, and terminate.
Wherein, including MPPT mode jumps to straight-through modal control method, and is periodically executed with certain time length, step For：
Judge whether work at present mode is MPPT mode, if not then terminating；If so, having：
Judge whether current duty cycle D is more than or equal to the threshold value D for jumping to straight-through modemppt2dc, if so, being jumped from MPPT mode Straight-through mode is gone to, and is terminated；
If being less than, directly terminate.
Compared to the prior art, according to above-mentioned control program formed the invention has the advantages that：
1）According to MPPT Controlling principles, the component of mismatch since it is desired that decompression work, can maintain MPPT operation modes always, There is no the component duty ratio D of mismatch that can incrementally increase, until jumping to straight-through mode, and maintains to lead directly to mode；System is whole in this way Body running state is that mismatch component operation is in MPPT mode, and the component operation of mismatch is not in straight-through mode so that system is each Component all realizes maximum power point tracking, while not will produce additional switching loss again（There is no the component optimizer of mismatch Pass-through state will be operated in）；
2）The synchronised clock generated using inspection optimization device electric current when inverter startup, optimizer are periodically executed in timer Disconnected, every optimizer periodically enters MPPT mode simultaneously again in system, if system mismatch condition changes（Such as shade with Sunlight moves）, then the working condition of each optimizer of system can be readjusted, confirms which optimizer needs to be operated in straight-through mould State, which optimizer need to be operated in MPPT mode；Communication system is not needed, you can realize that system MPPT controls and mode are jumped Turn, reduces system cost, improve reliability.
Description of the drawings
Fig. 1 is that there are the photovoltaic system PV curves of mismatch and the PV curve comparison figures for realizing component level MPPT；
Fig. 2 is voltage-dropping type photovoltaic optimization system figure；
Fig. 3 is the control method functional block diagram of the present invention
Fig. 4 a are control method flow chart of the present invention；
Fig. 4 b are control method flow chart of the present invention；
Fig. 4 c are control method flow chart of the present invention.
Specific implementation mode
The present invention is further described in conjunction with attached drawing.
Show one embodiment of the present of invention referring to Fig. 1 to Fig. 4, Fig. 1 to Fig. 4, for the skill for making the present invention realize Art means, creation characteristic, reached purpose and effect are easy to understand, and the present invention is further explained.
For voltage-dropping type photovoltaic optimization system shown in Fig. 2, the present invention provides a kind of system controlling parties being simple and efficient Method neither makes all optimizers always work in MPPT states, causes additional switching loss, but independent of communication system into Row system controls, and increases system cost and reduces system reliability.
Referring to Fig. 4 a- Fig. 4 c, the concrete operations of the present embodiment are：
Timer synchronization starts control method（Periodically execute below step）：
A）First determine whether timer has been turned on；
If having been turned on, it is transferred to（1）-E）
If not yet starting, it is transferred to（1）-B）；
B）Optimizer is started with straight-through mode, it is ensured that be may be incorporated into inverter work, is transferred to step（1）-C）；
C）Inspection optimization device electric current Io, the current threshold I of setting timer startupinvon；If Io≥Iinvon, then it is transferred to step（1）- D）；
If Io<Iinvon, then it is transferred to step（1）-E）；
D）Start timer, is transferred to step（1）-E）；
E）Terminate.
Timer period interrupt control method：
A）Judge whether work at present mode is MPPT mode；
If so, entering step（2）-B）；
If it is not, then entering step（2）-C）；
B）MPPT mode is maintained, step is transferred to（2）-D）；
C）MPPT mode is jumped to from straight-through mode, is transferred to step（2）-D）；
D）Terminate.
MPPT mode jumps to straight-through modal control method（It is periodically executed with certain time length）, it is Voltage loop feedback control A part：
A）Judge whether work at present mode is MPPT mode；
If so, entering step（3）-B）；
If it is not, then entering step（3）-D）；
B）Judge whether current duty cycle D is more than the threshold value D for jumping to straight-through modemppt2dc；
If D >=Dmppt2dc, then it is transferred to step（3）-C）；
If D< Dmppt2dc, then it is transferred to step（3）-D）；
C）Straight-through mode is jumped to from MPPT mode, is transferred to step（3）-D）；
D）Terminate.
The embodiment of the present invention is uprushed using electric current when inverter startup as optimizer synchronous reference in array；Optimize first Device is started with direct mode operation, ensures that inverter can be incorporated in this way（Open-circuit voltage is sufficiently high）, when inverter startup, work as optimizer Detect that electric current increases to threshold value, i.e. Io≥Iinvon（IoFor optimizer electric current, IinvonStart the current threshold of timer for optimizer Value, it is very low）, indicate that inverter is opened, start the timer of starting guide device IC, because prominent with current synchronization in an array Increase, so thus having accomplished clock synchronization；Because when system mismatch condition changes, optimizer must be simultaneously in system Being in MPPT working conditions could realize that system component grade MPPT is adjusted, so must be using synchronization action come unified clock；
With certain time interval TcyclePeriodically enter timer interruption, TcycleIt can adjust, after entering the interrupt, judge optimizer work Make state, if place's MPPT working conditions, remain unchanged, if place leads directly to working condition, jump to MPPT working conditions, to ensure What is redirected is smooth, and initial duty cycle will be close to 100%, in this way when system mismatch condition changes, and timer interruption control can To ensure that system is readjusted, each optimizer in system is made to be operated in optimum state（MPPT states either through state State）；
Because when timer interruption, all optimizers can be made to be in MPPT working conditions, but to the component of not mismatch problems Optimizer for, can make system effectiveness higher, MPPT principles that optimizer duty ratio D can be made constantly to increase in pass-through state Add, just like lower part in Voltage Feedback control：Judge whether duty ratio is more than threshold value Dmppt2dc, if more than threshold value, then redirect To pass-through state；
When startup, photovoltaic optimizer is in straight-through mode, and string formation voltage each in this way is equal to the sum of each component open-circuit voltage, it is ensured that energy It is incorporated to inverter（If optimizer is started with MPPT mode, output voltage is uncertain, in fact it could happen that part string formation voltage is high, Part string formation voltage is low, and the high string formation of voltage is incorporated to inverter start-up operation, and the string formation for causing voltage low can not be incorporated to inversion Device）；After inverter startup, there is electric current in group start of string, judges to reach threshold value I when optimizer electric currentinvonWhen, optimizer controls IC Timer start because the affiliated assembly array inner assembly of inverter can start simultaneously, timer start have synchronism； Because optimizer must be in MPPT working conditions simultaneously in system could realize that system component grade MPPT is adjusted, must profit It with synchronization action come unified clock, periodically synchronizes optimizer and jumps to MPPT states, with according to the variation of mismatch condition, weight The working condition of each optimizer of new regulating system；Timer starts control flow chart as shown in Fig. 3 corresponding portions；
After timer starts, periodically enter fixed duration TcycleTimer interruption, duration TcycleIt is adjustable, into interruption Afterwards, judge optimizer operation mode, if being in MPPT operation modes, remain unchanged, if being in straight-through operation mode, jump to MPPT operation modes, smooth to ensure to redirect, the initial duty cycle for being transferred to MPPT mode will be close to 100%；Timer interruption control Flow chart processed is as shown in Fig. 3 corresponding portions；
Because when timer interruption occurs, all optimizers can be made to be in MPPT working conditions, but to not mismatch problems For the optimizer of component, system effectiveness higher can be made in pass-through state（MPPT principles can make its automatic running to through state State）, periodically executed just like lower part in Voltage Feedback control：Judge whether duty ratio is more than threshold value Dmppt2dc, if more than Threshold value then jumps to straight-through mode；
It follows that the electric current when present invention is using inverter startup is uprushed, optimizer clock is set to synchronize, periodical rebound MPPT State, to re-start adjusting according to the variation of system mismatch situation, the component operation of mismatch is in MPPT states, without mismatch Component pass-through state can be readjusted according to MPPT principles；The MPPT controls of system were both ensure that in this way so that do not lose The component matched can still be operated in pass-through state, avoid additional loss, while also not needing communication system and carrying out system control, increase Adding system cost and reduction system reliability.
Embodiments of the present invention are described above in conjunction with accompanying drawings and embodiments, and the structure that embodiment provides is not constituted pair The limitation of the present invention, those skilled in the art in the art can be according to needing to adjust, within the scope of the appended claims Various deformations or amendments are made in protection domain.

Claims (3)

1. a kind of voltage-dropping type photovoltaic optimization system control method, it is characterised in that：Start control method including timer synchronization, For periodical execution, step is：
It first determines whether timer has been turned on, terminates if starting；
If not actuated, have：Optimizer is started with straight-through mode, and ensures to may be incorporated into inverter work；Then inspection optimization device Electric current Io, the current threshold I of setting timer startupinvon, then have：
If Io≥Iinvon, then start timer, and terminate；
If Io<Iinvon, then terminate.
2. a kind of voltage-dropping type photovoltaic optimization system control method, it is characterised in that：Including timer period interrupt control method, Step is：
First determine whether work at present mode is MPPT mode, if so, maintaining MPPT mode；
If it is not, then leading directly to mode jumps to MPPT mode, and terminate.
3. a kind of voltage-dropping type photovoltaic optimization system control method, it is characterised in that：Straight-through mode control is jumped to including MPPT mode Method processed, and periodically executed with certain time length, step is：
Judge whether work at present mode is MPPT mode, if not then terminating；If so, having：
Judge whether current duty cycle D is more than or equal to the threshold value D for jumping to straight-through modemppt2dc, if so, C）From MPPT mode Straight-through mode is jumped to, and is terminated；
If being less than, directly terminate.
CN201711282374.7A 2017-12-07 2017-12-07 A kind of voltage-dropping type photovoltaic optimization system control method being simple and efficient Pending CN108512415A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109104077A (en) * 2018-10-12 2018-12-28 阳光电源股份有限公司 Photovoltaic module power converter overheat protector control method and device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107247475A (en) * 2017-04-25 2017-10-13 北京交通大学 Suitable for the stagnant ring disturbance global maximum power point tracking method of band of photovoltaic optimizer
CN107359792A (en) * 2017-09-11 2017-11-17 阳光电源股份有限公司 A kind of power optimization device and its control method and control device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107247475A (en) * 2017-04-25 2017-10-13 北京交通大学 Suitable for the stagnant ring disturbance global maximum power point tracking method of band of photovoltaic optimizer
CN107359792A (en) * 2017-09-11 2017-11-17 阳光电源股份有限公司 A kind of power optimization device and its control method and control device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109104077A (en) * 2018-10-12 2018-12-28 阳光电源股份有限公司 Photovoltaic module power converter overheat protector control method and device

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