CN105490302B - A kind of more level photovoltaic inverters without alterating and direct current flow sensor - Google Patents
A kind of more level photovoltaic inverters without alterating and direct current flow sensor Download PDFInfo
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- CN105490302B CN105490302B CN201610044461.8A CN201610044461A CN105490302B CN 105490302 B CN105490302 B CN 105490302B CN 201610044461 A CN201610044461 A CN 201610044461A CN 105490302 B CN105490302 B CN 105490302B
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- 238000009826 distribution Methods 0.000 abstract description 3
- 238000000034 method Methods 0.000 abstract description 3
- 230000009466 transformation Effects 0.000 abstract description 2
- 238000010248 power generation Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
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Classifications
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- H02J3/385—
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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
- H02J3/01—Arrangements for reducing harmonics or ripples
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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
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/483—Converters with outputs that each can have more than two voltages levels
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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
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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
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
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- Inverter Devices (AREA)
Abstract
The present invention relates to a kind of more level photovoltaic inverters without alterating and direct current flow sensor, belong to generating, power transformation or distribution technique field.The inverter includes inverter controller, MPPT controller, DC boosting unit, multi-level inverse conversion unit, trapper；DC boosting unit, multi-level inverse conversion unit, trapper are sequentially connected in series；The control terminal of inverter controller is connected with multi-level inverse conversion unit controlled end, and the control terminal of MPPT controller is connected with the controlled end of DC boosting unit；The communication terminal of inverter controller is connected with the communication terminal of MPPT controller, and the voltage signal inputs of inverter controller are connected with the output end of voltage transformer.The present invention passes through trapper and eliminates the caused high frequency harmonic components on inverter circuit so that does not have high frequency harmonic components during the grid-connected power supply of generating set.
Description
Technical field
The present invention relates to a kind of more level photovoltaic inverters without alterating and direct current flow sensor, belong to generating, power transformation
Or distribution technique field.
Background technology
The energy is the material base that human society exists and developed.Energy scarcity, being on the rise for environmental degradation are at present
Concern the global problem of human survival and development.Regenerative resource belongs to the clean energy resource that can be recycled, due to its resource
Very abundant, and without geographical restrictions, can local use, there is huge development potentiality and application prospect, be future source of energy system
The hope of system.
Solar energy is a kind of regenerative resource of flood tide, and the energy very abundant of direct solar radiation to the earth, distribution is extensively
It is general, do not pollute the environment, cleaning is clean.China also possesses abundant solar energy resources, and current developable solar energy is 21039
Hundred million kilowatts, if 1% Deserts in China is loaded onto into photovoltaic, total capacity is up to 1,300,000,000 kilowatts, and more than China, all energy are sent out at present
The installed capacity of electricity.
Countries in the world today particularly developed country attaches great importance to photovoltaic power generation technology, and its development and utilization has been subjected to
Decades, it is increasingly becoming the cutting edge technology in green energy resource field.In the world, photovoltaic generation is no matter technically or from scale
Comparative maturity, the commercial operations stage is had been enter into, and have been mainly used for generating electricity by way of merging two or more grid systems for city.China's photovoltaic
Generating is started late, and the middle and later periods eighties begins to take shape, and technology is gone back at continuous maturation, either industrialization aspect since the nineties
It is that application aspect all have developed rapidly, at present apply generates electricity more in outlying areas without electricity stand alone type, such as in Gansu, Tibet, Xinjiang
Etc. ground establish electric power facility based on photovoltaic generation.And generate electricity by way of merging two or more grid systems and urban applications are started late, as country is right
A series of promulgation of the pay attention to day by day of new energy and preferential policies, China's solar power generation rapid development, 2013 annual newly-increased
Capacity is nearly 3 times in 2012, to the end of the year 2013, China's Photovoltaic generation installed capacity is more than 17,000,000 thousand more than 10,000,000
Watt.
Grid-connected photovoltaic power generation is that the DC inverter that photovoltaic battery panel exports is accessed into power network into exchange by photovoltaic DC-to-AC converter,
Inverter contains high-frequency harmonic caused by certain HF switch, and large-scale photovoltaic electricity generation grid-connecting also brings harmonic problem, high frequency
The harm of harmonic wave is serious.The method for taking LC or LCL filtering in parallel in the past, still there is certain high-frequency harmonic injection power network, though
The waveform of right three-level inverter is better than two-level inverter, but can't filter out radio-frequency component completely.
The content of the invention
The technical problem to be solved in the present invention is, in view of the shortcomings of the prior art, it is grid-connected to propose that one kind filters out using trapper
The inverter of high fdrequency component in electric current.
The present invention is to solve the technical scheme that above-mentioned technical problem proposes to be：It is a kind of without the more of alterating and direct current flow sensor
Level photovoltaic inverter, it is characterised in that including：Inverter controller, MPPT controller, DC boosting unit, multi-level inverse conversion
Unit and trapper；The DC boosting unit, multi-level inverse conversion unit and trapper are sequentially connected in series, the output of the trapper
End is connected with voltage transformer；The control terminal of the inverter controller is connected with the multi-level inverse conversion unit controlled end, described
The control terminal of MPPT controller is connected with the controlled end of the DC boosting unit；The communication terminal of the inverter controller with it is described
The communication terminal of MPPT controller is connected, the output end of the voltage signal inputs of the inverter controller and the voltage transformer
It is connected；After the inverter controller receives the voltage on the voltage transformer, feedforward control calculating is carried out, then by result of calculation
The MPPT controller is fed back to, the MPPT controller controls turning for the DC boosting unit according to the feedback result received
Coefficient is changed, to ensure that the DC boosting unit is transferred to the level constant of the multi-level inverse conversion unit.
The improvement of above-mentioned technical proposal is：It is based on the trapper without ac and dc current that the feedforward control, which calculates,
Grid side voltage feedforward control calculate, the feedforward control calculate include first arithmetic device export f1Calculate, second arithmetic device
Export f2Calculate, the 3rd arithmetic unit output f3Calculate, the 4th arithmetic unit output f4Calculate and the 5th arithmetic unit exports f5Calculate, calculate
Formula is as follows,
f1=i*-i × H (s)
f2=f1×Gi(s)
f3=(f2-e*)/ZL
f4=i-f3
f5=e*-Vac
E*=f4×ZC
I=f5/ZLC
In above formula,
E* is the output voltage calculated value of the multi-level inverse conversion unit；
VacFor the voltage on line side measured value of the trapper；
I is the estimated value of the trap current；
i*For the current on line side reference value of the trapper；
H (s) be the trap current feedback factor, 0<||H(s)||<1；
Gi(s) it is system transter, 0<||Gi(s)||<1；
ZL(s) it is the inductive impedance of the trapper, ZC(s) it is the condensance of the trapper, ZLCFor the trap
The comprehensive impedance of electric capacity and inductance in device loop；
In addition, on the dc bus of the DC boosting unit output end power calculated valueFor
η is the conversion efficiency of the multi-level inverse conversion unit.
The improvement of above-mentioned technical proposal is：The trapper is a shunt-resonant circuit, and forms the parallel resonance
The inductance value L and capacitance C in loop and the switching frequency f of the multi-level inverse conversion unitsMeet
The improvement of above-mentioned technical proposal is：When the converter plant in the operating condition, the DC boosting unit be used for be
The multi-level inverse conversion unit provides constant level signal, and the multi-level inverse conversion unit is used to carry out the level signal received
Inversion exports alternating signal；The multi-level inverse conversion unit is three level electricity inverter circuits.
More level photovoltaic inverters provided by the invention in trapper are eliminated by trapper and produced on inverter circuit
Raw high frequency harmonic components so that do not have the entirety that high frequency harmonic components have influence on operation of power networks during the grid-connected power supply of generating set
It is stable.Simultaneously by line trap both end voltage, electric current is calculated, instead of AC current sensor；Calculated by conversion efficiency
Energy-storage units power output, eliminates direct current transducer, solves measurement accuracy that alternating current-direct current sensor brings and stability is asked
Topic.
Brief description of the drawings
The invention will be further described below in conjunction with the accompanying drawings：
Fig. 1 is a preferred embodiment structural representation of the invention.
Fig. 2 is the structural representation of the multi-level inverse conversion unit in Fig. 1.
Fig. 3 is the circuit diagram of inverter controller in Fig. 1.
Fig. 4 is the circuit diagram of MPPT controller in Fig. 1.
Fig. 5 is the logic diagram that feedforward control of the embodiment of the present invention calculates.
Label is schematically as follows in figure：1- inverter controllers, 2-MPPT controllers, 3- DC boosting units, 4- is more, and level is inverse
Become unit, 5- trappers.
Embodiment
Embodiment
More level photovoltaic inverters without alterating and direct current flow sensor of the present embodiment, as shown in figure 1, including：It is inverse
Become controller 1, MPPT controller 2, DC boosting unit 3, multi-level inverse conversion unit 4 and trapper 5.It is DC boosting unit 3, more
Level inverse conversion unit 4 and trapper 5 are sequentially connected in series, and the output end of the trapper 5 is connected with voltage transformer；Inverter controller
1 control terminal is connected with the controlled end of multi-level inverse conversion unit 4, the control terminal of MPPT controller 2 and DC boosting unit 3 by
Control end is connected；The communication terminal of inverter controller 1 is connected with the communication terminal of MPPT controller 2, and the voltage signal of inverter controller 1 is defeated
Enter end with the output end of voltage transformer 6 to be connected.
Multi-level inverse conversion unit 4 is as shown in Fig. 2 using three-level inverter circuit, the waveform after such inversion is closer
Sine wave.
As shown in figure 4, MPPT controller 2 is existing MPPT maximum power point tracking controller (maximum power point
tracking).DC boosting unit 3 is combined by MPPT controller 2, gives full play to the efficiency of solar panel.
As shown in figure 3, inverter controller 1 is used to collect the voltage on voltage transformer 6, and proceed without ac and dc current
The grid side voltage based on the trapper 5 feedforward control calculate, the feedforward control calculate as shown in figure 5, including first
Arithmetic unit exports f1Calculate, second arithmetic device output f2Calculate, the 3rd arithmetic unit output f3Calculate, the 4th arithmetic unit output f4Meter
Calculate and the 5th arithmetic unit exports f5Calculating, formula is as follows,
f1=i*-i × H (s)
f2=f1×Gi(s)
f3=(f2-e*)/ZL
f4=i-f3
f5=e*-Vac
E*=f4×ZC
I=f5/ZLC
In above formula,
E* is the output voltage calculated value of multi-level inverse conversion unit 4；
VacFor the voltage on line side measured value of trapper 5；
I is the estimated value of the electric current of trapper 5；
i*For the current on line side reference value of trapper 5；
H (s) be the electric current of trapper 5 feedback factor, 0<||H(s)||<1；
Gi(s) it is system transter, 0<||Gi(s)||<1；
ZL(s) it is the inductive impedance of trapper 5, ZC(s) it is the condensance of trapper 5, ZLCFor electricity in the loop of trapper 5
Hold the comprehensive impedance with inductance；
In addition, on the dc bus of the output end of DC boosting unit 3 power calculated valueFor
η be multi-level inverse conversion unit 4 conversion efficiency, η=0.98.
Calculated by above-mentioned feedforward control, its corresponding circuit of each feedback control, the trapper 5 in actual measurement situation
Grid side voltage Vac, the output end of DC boosting unit 3 DC bus-bar voltage VdcAnd photovoltaic power generation apparatus PV output voltage Vb
Value etc. parameter determines how whole device should adjust.Wherein, power on the dc bus of the output end of DC boosting unit 3
Measured value is Pdc, the measured value P of the powerdcWith the d-c bus voltage value V of the output end of DC boosting unit 3dcIt is directly proportional；Directly
Flow the output end voltage value V of boosting unit 3dcWith photovoltaic power generation apparatus PV output voltage VbDirectly proportional, proportionality coefficient is direct current liter
The boosting coefficient of unit 3 is pressed, according to performance number on the dc bus of the output end of DC boosting unit 3 of actual measurement and the direct current of calculating
Performance number relatively adjusts the boosting coefficient of stream boosting unit 3 to ensure to be transported on the dc bus of the output end of boosting unit 3
The voltage constant of three-level inverter circuit.
And result of calculation is sent to MPPT controller 2, MPPT controller 2 direct current liter is controlled according to the feedback result received
Pressure unit 3 ensures to be transferred to the level constant of multi-level inverse conversion unit 4.
The trapper 5 of the present embodiment is an antiresonant circuit.From suitable inductance L and electric capacity C, filter out by upper one
Level multi-level inverse conversion unit 4 produces high frequency harmonic components, inductance L and electric capacity C values and the switching frequency f of multi-level inverse conversion unit 4s
Meet formula：
The inverter controller of the present embodiment has powerful computing using DSP28335 high-performance multi-core DSP chips
Ability and antijamming capability, it is ensured that the present embodiment operation it is efficient and stably.
The present invention is not limited to above-described embodiment.All technical schemes formed using equivalent substitution, all falling within the present invention will
The protection domain asked.
Claims (2)
- A kind of 1. more level photovoltaic inverters without alterating and direct current flow sensor, it is characterised in that including：Inversion control Device, MPPT controller, DC boosting unit, multi-level inverse conversion unit and trapper；The DC boosting unit, multi-level inverse conversion Unit and trapper are sequentially connected in series, and the output end of the trapper is connected with voltage transformer；The control of the inverter controller End is connected with the multi-level inverse conversion unit controlled end, the control terminal of the MPPT controller and the DC boosting unit by Control end is connected；The communication terminal of the inverter controller is connected with the communication terminal of the MPPT controller, the inverter controller Voltage signal inputs are connected with the output end of the voltage transformer；The inverter controller is receiving the mutual induction of voltage After voltage on device, feedforward control calculating is carried out, then result of calculation is fed back into the MPPT controller, the MPPT controller To control the conversion coefficient of the DC boosting unit according to the feedback result received；It is without handing over that the feedforward control, which calculates, The feedforward control of the grid side voltage based on the trapper of DC current calculates, and the feedforward control, which calculates, includes the first computing Device exportsf 1 Calculate, second arithmetic device outputf 2 Calculate, the output of the 3rd arithmetic unitf 3 Calculate, the output of the 4th arithmetic unitf 4 Calculate and 5th arithmetic unit exportsf 5 Calculating, formula is as follows,f 1=i*-i×H(s)f 2=f 1×G i (s)f 3=（f 2- e*）/ Z Lf 4=i- f 3f 5=e*-V ace*=f 4×Z Ci= f 5/ Z LCIn above formula,e*For the output voltage calculated value of the multi-level inverse conversion unit；V ac For the voltage on line side measured value of the trapper；iFor the estimated value of the trap current；i * For the current on line side reference value of the trapper；H(s) it is the feedback factor of the trap current, 0<|| H(s)||<1；G i (s) it is system transter, 0<|| G i (s)||<1；Z L (s) it is the inductive impedance of the trapper,Z C (s) it is the condensance of the trapper,Z LC For the trapper loop The comprehensive impedance of middle electric capacity and inductance；In addition, on the dc bus of the DC boosting unit output end power calculated valueFor,ηFor the conversion efficiency of the multi-level inverse conversion unit.
- 2. more level photovoltaic inverters without alterating and direct current flow sensor as claimed in claim 1, it is characterised in that：Institute It is a shunt-resonant circuit to state trapper, and forms the inductance value L and capacitance C of the shunt-resonant circuit and the electricity more The switching frequency of flat inversion unitf s Meet。
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Citations (3)
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|---|---|---|---|---|
| CN101902145A (en) * | 2009-05-28 | 2010-12-01 | 通用电气公司 | Solar inverter and control method |
| CN104932285A (en) * | 2015-05-15 | 2015-09-23 | 华北电力大学（保定） | Photovoltaic power generation system equivalent modeling method |
| CN205753439U (en) * | 2016-01-22 | 2016-11-30 | 国家电网公司 | A kind of many level photovoltaic inverter without alterating and direct current flow sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20140070614A1 (en) * | 2012-09-07 | 2014-03-13 | Atomic Energy Council-Institute Of Nuclear Energy Research | Household Grid-Connected Inverter Applied to Solar Power Generation System with Maximum Power Tracking Function |
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- 2016-01-22 CN CN201610044461.8A patent/CN105490302B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101902145A (en) * | 2009-05-28 | 2010-12-01 | 通用电气公司 | Solar inverter and control method |
| CN104932285A (en) * | 2015-05-15 | 2015-09-23 | 华北电力大学（保定） | Photovoltaic power generation system equivalent modeling method |
| CN205753439U (en) * | 2016-01-22 | 2016-11-30 | 国家电网公司 | A kind of many level photovoltaic inverter without alterating and direct current flow sensor |
Non-Patent Citations (1)
| Title |
|---|
| 一种新的光伏系统最大功率跟踪控制方法;赵志;《电源学报》;20150515;第13卷(第3期);第119-120页 * |
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