CN109286201A - A kind of duty ratio control method based on power feedforward mode - Google Patents
A kind of duty ratio control method based on power feedforward mode Download PDFInfo
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- CN109286201A CN109286201A CN201810781176.3A CN201810781176A CN109286201A CN 109286201 A CN109286201 A CN 109286201A CN 201810781176 A CN201810781176 A CN 201810781176A CN 109286201 A CN109286201 A CN 109286201A
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- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000010248 power generation Methods 0.000 claims abstract description 8
- 230000001360 synchronised effect Effects 0.000 claims description 4
- 238000005286 illumination Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims 1
- 239000003990 capacitor Substances 0.000 description 5
- 230000007613 environmental effect Effects 0.000 description 5
- 238000011217 control strategy Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011897 real-time detection Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 230000011664 signaling Effects 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
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- H02J3/383—
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
- H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
-
- 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
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
Abstract
The invention patent relates to a kind of duty ratio control methods based on power feedforward mode.The method is mainly used in the low voltage crossing operating condition of two-stage type grid-connected photovoltaic system.By detecting photovoltaic power generation grid-connecting point voltage dip information, calculate grid entry point voltage dip size, according to photovoltaic power generation low voltage crossing standard and actual condition, it can obtain and refer to active and reactive current, calculate the exportable active power of inverter at this time, again according to photovoltaic battery panel voltage and power output relation property, it finds the exportable active power of inverter and corresponds to photovoltaic cell output voltage point, duty ratio is calculated by the amplitude of corresponding voltage point and the ratio of inverter direct-flow side capacitance voltage reference value.The duty ratio that can be switched to by the duty ratio under original maximum power tracing mode when voltage dip occurs for photovoltaic system grid entry point under power feedforward mode, the power-balance of the output power from photovoltaic cells and inverter output power can be achieved, reduce the fluctuation size of inverter direct-flow side capacitance voltage, inverter output current is limited, and issues reactive power support grid entry point voltage.
Description
Technical field
The invention patent relates to new energy two-stage type grid-connected photovoltaic system low voltage crossing technical field, it is specific and
Speech is a kind of DC/DC converter duty ratio control method of two-stage type photovoltaic parallel in system realization low voltage crossing.
Background technique
The mankind make making full use of for renewable energy become the whole world common recognition worry of energy security and environmental degradation.With
Solar energy, the new energy grid-connected power that wind energy is representative have become the irresistible development trend of novel electric power system.Power grid
It is to utilize directly excision new energy when new-energy grid-connected capacity is smaller when open circuit fault or other voltage landing situations occur
Generating equipment, but it is larger with power grid specific gravity shared by new energy installed capacity when, cut off new energy equipment or cause power grid
The accidents such as power swing, so needing to guarantee that new energy equipment is held when open circuit or voltage dip failure occur for power grid
Reforwarding row, reduces the impact to power grid, and the low voltage crossing technology for studying new energy is just particularly important.In grid-connected hair
In electric system, if grid entry point voltage occurs three-phase symmetrical and temporarily drops, inverter direct-flow side capacitance voltage can be caused to increase inverter mistake
Two large problems are flowed, solution and control strategy only reduce capacitance voltage amplitude of variation at present, limit inverter output current
Size, there are still following problems: can not be precisely controlled the duty ratio of DC booster converter DC/DC；It can not fast implement
Photovoltaic output power and inverter output power balance；Globality and connection when to photovoltaic power generation grid-connecting system low-voltage fault traversing
Dynamic property is poor.
Patent of invention content
The invention patent in view of the above problems, provides a kind of duty ratio controlling party based on power feedforward mode
Method realizes the power-balance of the output power from photovoltaic cells and inverter output power when grid entry point voltage reduces, and reduces inversion
The fluctuation size of device DC capacitor voltage limits inverter output current, and issues reactive power support grid entry point voltage.
The invention patent to achieve the above object, takes following technical scheme to be achieved: calculating equipment and obtains acquisition
Voltage signal is sent to control device for inverter signal receiver, according to voltage dip detection information, if grid entry point voltage is temporary
Drop, inverter startup power feed-forward mode immediately.
The acquisition of voltage dip information is using d shaft voltage of the grid entry point voltage under synchronous rotating frame, to calculate
Voltage dip amplitude out.In conjunction with parallel network power generation low voltage crossing standard and actual environment situation, reactive current is first calculated
Reference value.Theoretic watt current is calculated by inverter maximum current overload values and reactive current reference value again to refer to
Value.The closed loop current before falling is compared, choosing lesser watt current reference value can get the watt current for meeting actual condition
Reference value.
Operation reference power after calculating grid entry point voltage dip, according to the synchronous rotary after acquisition grid entry point Voltage Drop
D shaft voltage value under coordinate system can get using the product of d shaft voltage value and meritorious reference current value after temporarily drop with reference to active
Performance number.
Active power reference value after calculating grid entry point Voltage Drop by inverter control system is transferred to DC/DC change
Parallel operation provides and calculates accurate duty cycle reference power.Using photovoltaic cell voltage and power out-put characteristic, according to reference wattful power
Rate value, intensity of illumination, environment temperature and photovoltaic array basic parameter find out the photovoltaic cell output voltage values under reference power.
It is compared by calculated photovoltaic cell output voltage values with DC capacitor voltage reference value, can get DC/DC converter and account for
Empty ratio.
The invention patent has the following beneficial effects: compared with the existing technology is precisely controlled DC/DC converter duty ratio, will
DC voltage voltage fluctuation is preferably minimized；The grid-connected photovoltaic system low-voltage that can be applied under any environmental working condition is worn
More；By current limliting and reactive power and the control of voltage fluctuation of capacitor problem consistency are issued, is conducive to the stabilization of grid-connected control.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the embodiment of the present invention two-stage type grid-connected photovoltaic system.
Fig. 2 is the principle assumption diagram of the duty ratio control based on power feedforward.
Fig. 3 is power feedforward mode device signal transmission path.
Specific embodiment
It is described in detail below in conjunction with embodiment of the attached drawing to the invention patent:
As shown in Figure 1, building parallel network power generation model, photovoltaic parallel in system is in normal conditions, electric using d axis power grid
Vector oriented and double PI control strategies are pressed, the control method of outer voltage current inner loop guarantees inverter direct-flow side capacitance voltage
Stablize, photovoltaic cell peak power output is controlled using the duty ratio D of DC/DC converter, realizes maximum power tracing.
As shown in Fig. 2, the realization principle block diagram of power feedforward mode.When photovoltaic system is incorporated into the power networks, if net side occurs
Failure causes grid entry point voltage generation hree-phase symmetry temporarily to drop, and can cause the output power from photovoltaic cells and inverter output work at this time
Rate occurs unbalanced power and DC capacitor voltage is caused to rise sharply, to influence the capacitor service life.This problem is proposed in event
The maximum tracking power mode of operation of photovoltaic system is switched to power feedforward mode when barrier occurs.Duty based on power feedforward
It is as follows than control specific implementation process:
Step 1: calculating the voltage signal that equipment obtains acquisition, it is sent to control device for inverter signal receiver, is calculated
Voltage dip amplitude out calculates idle reference in conjunction with parallel network power generation low voltage crossing standard and actual environment situation
Electric current and meritorious reference current.Voltage dip information is detected first, according to voltage dip amplitude and idle sending requirement, determines nothing
Function reference current Iqref:
Wherein, Δ U is Voltage Drop size；UtTo fall rear voltage magnitude；Ut-TFall the voltage in previous period；UNFor
Exchange side voltage rating；INFor ac-side current rated value.
According to IqrefWith the requirement of actual condition, meritorious reference current can be obtained:
Wherein, ImaxThe maximum current value that can bear for inverter；ImpptFor current reference value under maximum power tracing,
Current reference value before falling.
Step 2: calculating the operation reference power after grid entry point voltage dip, step includes: that Grid-connected Control Strategy uses
D axis network voltage vector oriented control strategy, is converted into synchronous rotary dq axis for collected three-phase voltage signal, can get d
Shaft voltage value.It can get using the product of d shaft voltage value and meritorious reference current after temporary drop and refer to active power value.Calculating has
Function value and power reference PrefAre as follows:
Third step calculates the mode for obtaining duty ratio, and step includes: to utilize photovoltaic cell voltage and power out-put characteristic, root
According to reference active power value, intensity of illumination and environment temperature, the photovoltaic cell output voltage values under reference power are found out.Pass through meter
The photovoltaic cell output voltage values of calculating are compared with inverter direct-flow side capacitance voltage reference value, be can get DC/DC converter and are accounted for
Empty ratio.Biggish reference power working voltage point is found out according to the power of photovoltaic cell and voltage change curve again:
f(Pref, Ir, T) and=Vpv-ref
Wherein, Ir is current light intensity；T current environmental temperature；Vpv-refFor photovoltaic cell exit potential.
According to relationship of the DC side reference voltage between photovoltaic operating voltage, DC/DC duty ratio D can be determined:
D=1-Vpv-ref/Vdc-ref
Wherein, Vdc-refFor inverter direct-flow side reference voltage.
As shown in figure 3, duty ratio control process is realized in power feedforward mode signaling and calculating.Based on Fig. 2 with more than
The principle analysis of power feedforward mode further illustrates the duty ratio control implementation process of materialization.It is filled by voltage signal acquisition
It sets and grid entry point voltage is acquired in real time, collected voltage signal is transmitted to DC-to-AC converter, inverter passes through to electricity
Signal test and evaluation is pressed, amplitude can be fallen with real-time detection grid entry point voltage, by the transmission of temporary drop information and inversion of voltage
Device grid-connection control system, calculates active power reference value, DC/DC convertor device is immediately conveyed to, further according to environmental data
The environmental data that measuring device provides in real time calculates the accurate duty ratio of achievable power-balance, to control DC/DC converter
Switch.
Only as described above, the only preferred embodiment of the invention patent, when this practical invention cannot be limited with this
The range of patent, i.e., in every case according to simple equivalent made by content documented by the invention patent claim and description of the invention
Variation and modification, all still belong within the invention patent claim scope.In addition, abstract part and title are intended merely to
Auxiliary patent document search is used, and is not intended to limit the invention the interest field of patent.
Claims (6)
1. one kind is based on power feedforward mode duty cycle control method, the low-voltage applied to two-stage type photovoltaic power generation grid-connecting system
Pass through operating condition.It is characterized in that, precisely adjusting DC/DC converter duty ratio using a kind of control model, realize that low-voltage is worn
More, which comprises
The voltage signal that equipment obtains acquisition is calculated, control device for inverter signal receiver is sent to, is examined according to voltage dip
Measurement information, if grid entry point voltage dip, inverter startup power feed-forward mode immediately.
2. being required described in method according to right 1, which is characterized in that the acquisition of voltage dip information is using grid entry point voltage same
The d shaft voltage under rotating coordinate system is walked, to calculate voltage dip amplitude.
3. a kind of duty ratio control method based on power feedforward mode, it is characterised in that DC-to-AC converter meritorious reference current value
Selection, step includes:
In conjunction with parallel network power generation low voltage crossing standard and actual environment situation, reactive current reference value is first calculated.
Theoretic watt current reference value is calculated by inverter maximum current overload values and reactive current reference value again.
The closed loop current before falling is compared, choosing lesser watt current reference value can get the watt current for meeting actual condition
Reference value.
4. a kind of duty ratio control method based on power feedforward mode, which is characterized in that after calculating grid entry point voltage dip
Reference power is run, step includes:
The d shaft voltage value under synchronous rotating frame after obtaining grid entry point Voltage Drop
It can get using the product of d shaft voltage value and meritorious reference current value after temporary drop and refer to active power value.
5. being required described in method according to right 4, which is characterized in that after calculating grid entry point Voltage Drop by inverter control system
Active power reference value, be transferred to DC/DC converter, provide and calculate accurate duty cycle reference power.
6. a kind of duty ratio control method based on power feedforward mode, the method is applied to DC/DC converter duty ratio
Control model, it is characterised in that calculate the mode for obtaining duty ratio, step includes:
Using photovoltaic cell voltage and power out-put characteristic, according to reference active power value, intensity of illumination, environment temperature and photovoltaic
Array basic parameter finds out the photovoltaic cell output voltage values under reference power.
It is compared by calculated photovoltaic cell output voltage values with inverter direct-flow side capacitance voltage reference value, can get DC/
DC converter duty ratio.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201810781176.3A CN109286201A (en) | 2018-07-17 | 2018-07-17 | A kind of duty ratio control method based on power feedforward mode |
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| CN201810781176.3A CN109286201A (en) | 2018-07-17 | 2018-07-17 | A kind of duty ratio control method based on power feedforward mode |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110233501A (en) * | 2019-06-25 | 2019-09-13 | 福州大学 | A kind of three-phase photovoltaic grid-connected electricity generation system low voltage traversing control method of two-stage |
| CN111525605A (en) * | 2020-04-07 | 2020-08-11 | 北方工业大学 | Photovoltaic system low voltage ride through method and system based on variable power output control |
| CN114142526A (en) * | 2021-12-17 | 2022-03-04 | 深圳市中旭新能源有限公司 | Photovoltaic power generation system with series conversion stage voltage optimization control |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103997066A (en) * | 2014-06-13 | 2014-08-20 | 苏州大学 | Inverting control system and method based on grid drop testing in photovoltaic power generation system |
| CN104269878A (en) * | 2014-07-29 | 2015-01-07 | 西安交通大学 | Low-voltage ride through control method for grid-connected photovoltaic power generation system capable of providing reactive support |
| CN107732956A (en) * | 2017-07-10 | 2018-02-23 | 华北电力大学（保定） | The two-stage type photovoltaic parallel in system low-voltage ride-through method of Variable power pursuit path |
-
2018
- 2018-07-17 CN CN201810781176.3A patent/CN109286201A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103997066A (en) * | 2014-06-13 | 2014-08-20 | 苏州大学 | Inverting control system and method based on grid drop testing in photovoltaic power generation system |
| CN104269878A (en) * | 2014-07-29 | 2015-01-07 | 西安交通大学 | Low-voltage ride through control method for grid-connected photovoltaic power generation system capable of providing reactive support |
| CN107732956A (en) * | 2017-07-10 | 2018-02-23 | 华北电力大学（保定） | The two-stage type photovoltaic parallel in system low-voltage ride-through method of Variable power pursuit path |
Non-Patent Citations (2)
| Title |
|---|
| YAN LI等: "Low Voltage Ride-through of PV System Based on APFF", 《20182NDIEEECONFERENCEONENERGYINTERNETAND》 * |
| 刘雅楠: "光伏并网系统低电压穿越技术的研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110233501A (en) * | 2019-06-25 | 2019-09-13 | 福州大学 | A kind of three-phase photovoltaic grid-connected electricity generation system low voltage traversing control method of two-stage |
| CN111525605A (en) * | 2020-04-07 | 2020-08-11 | 北方工业大学 | Photovoltaic system low voltage ride through method and system based on variable power output control |
| CN111525605B (en) * | 2020-04-07 | 2021-08-31 | 北方工业大学 | Photovoltaic system low voltage ride through method and system based on variable power output control |
| CN114142526A (en) * | 2021-12-17 | 2022-03-04 | 深圳市中旭新能源有限公司 | Photovoltaic power generation system with series conversion stage voltage optimization control |
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Application publication date: 20190129 |