CN107453636A - A kind of 9 new level offshore wind farm grid-connected inverter systems - Google Patents

A kind of 9 new level offshore wind farm grid-connected inverter systems Download PDF

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CN107453636A
CN107453636A CN201710821710.4A CN201710821710A CN107453636A CN 107453636 A CN107453636 A CN 107453636A CN 201710821710 A CN201710821710 A CN 201710821710A CN 107453636 A CN107453636 A CN 107453636A
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Henan University of Technology
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Henan University of Technology
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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
    • H02J3/386—
    • 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
    • H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
    • 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
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects

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

Abstract

The invention discloses a kind of 9 new level offshore wind farm grid-connected inverter systems, the system includes AC system, inverter system controller on offshore wind turbine controller, 9 level topology units, seashore；Two low frequency switch in system work in low frequency, and once for every half is only cut-off once, by the single flying capacitor feed-in H-bridge unit of cascade, avoid the mains side midpoint that load is directly connected in inverter circuit.Under same ac output voltage, voltage magnitude requirement of the present system to DC side power supply can reduce half, and can only be realized by a DC source feed-in；Under normal operation, the requirement to inverter circuit is reduced, and two low frequency switch cause the three-phase topological arrangement of inverter to become simpler.

Description

A kind of 9 new level offshore wind farm grid-connected inverter systems
Technical field
The invention belongs to the interconnection technology field of Oversea wind power generation, and in particular to a kind of 9 new level offshore wind farms are simultaneously Net inverter system.
Background technology
Wind energy is the fastest-rising energy in the world.Particularly in nearest 10 years, wind energy on the sea is with fastest developing speed Field of wind energy utilization, due to can at sea produce more powerful and stable wind, it can establish large-scale wind power plant.It is contemplated that At 10 years of future, installed capacity of wind-driven power will obtain more quick growth.In addition, land wind-power electricity generation is compared, it is existing Theoretical research and engineering practice are proved large-scale offshore wind generating not only installed capacity are larger, and cost of electricity-generating is lower.
In the exploitation of wind energy, in order to effectively carry out the transmission of energy with conversion, it is necessary to largely use transverter equipment, Among these, the design of the rectifier and inverter of transverter is most important.Effective transverter topological structure how is designed, makes to change The rectification side of device and the electric energy of inverter side transmission high quality are flowed, is always association area focus of attention and the focus of research.Wherein, Inverter is a kind of device for converting electric energy based on Power Electronic Technique, it by the transformation of electrical energy of the AC or DC of input into The AC energy of voltage and frequency needed for family.Powered compared to conventional AC power network, inverter has lot of advantages：
1) it can relatively easily change the items such as voltage, frequency of output electric energy and use parameter；
2) the DC form electric energy such as battery, wind energy, solar energy is converted into AC energy；
3) efficiency is higher, helps to save；
4) output electric energy is not influenceed by mains by harmonics；
5) protection is fast, adds the reliability with electric loading.
Preferable power supply should export the voltage or current waveform of sinusoidal power frequency, yet with inverter intrinsic property its Contain a large amount of harmonic waves in the electric energy directly exported, these harmonic waves equally can produce harm to electrical equipment, can influence electrical equipment Normal work.To enable inverter to export preferable waveform, basic ideas have two：First, the topology to inverter in itself Carry out improving on algorithm in structure and control system, inverter is exported preferable waveform.Current method is mainly ground with this Study carefully, the improvement of especially various control algolithms, although can play a role, can not eradicate.Especially PWM is inverse Become the voltage of device output as the impulse waveform of series of rectangular, rising edge and trailing edge are all very steep, long cable is produced ripple anti- Penetrate, cause cable overvoltage and puncture.
In summary, it is contemplated that the problems such as the quality of power supply that a large amount of conveyings of offshore wind farm face at present, it is necessary to a kind of new Be applied to the grid-connected inverter system of offshore wind farm to solve the above problems.
Invent new content
To overcome drawbacks described above, the invention provides a kind of 9 new level offshore wind farm grid-connected inverter systems, the inversion The control effect of device system is preferable.
To achieve the above object, the present invention provides a kind of inverter system, and it is theed improvement is that, the system includes sea Windward machine controller, 9 level topology units, AC system, inverter system controller on seashore；Wherein, offshore wind turbine controls Device is connected with 9 level topology units, 9 level topology units and AC system, inverter system on offshore wind turbine controller, seashore Controller is connected；AC system is connected with 9 level topology units, inverter system controller on seashore, inverter system control Device is connected with AC system on 9 level topology units, seashore；
9 level topology units include the flying capacitor C of offshore wind turbine DC sidedc, H bridge power units 1, H bridge power units 2nd, submodule S1And submoduleSubmodule S6And submoduleWherein, H bridge power units 1 are by submodule S2, submodule S3、 SubmoduleSubmoduleWith flying capacitor C1Composition, H bridge power units 2 are by submodule S4, submodule S5, submodule SubmoduleWith flying capacitor C2Composition；
The input signal of inverter system controller includes the voltage V of offshore wind turbine DC sideCdc, AC on seashore Voltage Vg, on seashore AC electric current ig, flying capacitor C in H bridge power units 11Voltage VC1And its reference valueH bridges Flying capacitor C in power cell 22Voltage VC2And its reference valueThe active power of inverterAnd reactive powerIt is inverse Become the output signal of device system controller as gate-control signal, for controlling submodule and electric capacity in 9 level topology units；
The level number N of 9 level topology unit output voltageslevelIt can be determined by following formula
Nlevel=4Ncell+1
Wherein, NcellRepresent the H-bridge unit number of series connection；9 level topology units share six groups of complementary on off states, point It is not：
The capacitance voltage of H bridge power units remains at a given level, and its numerical value is determined by following formula
Wherein, n=1 ..., 6；
The numerical value C of flying capacitor can be determined by following formula
Wherein, IpkRepresent the peak value of load current；ΔVcRepresent ripple voltage；fswRepresent switching frequency；
The flying capacitor C of H bridge power units 11With the flying capacitor C of H bridge power units 22Meet lower relation of plane
C2=2C1
Flying capacitor C1、C2Unit voltage deviation be respectively PC1、PC2, can be determined by following formula
Wherein, VC1、VC2C is represented respectively1、C2Voltage；V represents the output electricity of H bridge power units It is flat；Work as PC1＞ PC2When, show VC1Deviation be more than VC2Deviation；
The charged state or discharge condition of electric capacity can be determined by following formula
If COMP1=1, then electric capacity C1Need to charge；If COMP1=0, then electric capacity C1Need to discharge；If COMP2= 1, then electric capacity C2Need to charge；If COMP2=0, then electric capacity C2Need to discharge；
The foundation that on off state corresponding to each level selects is as follows：
1. the voltage level exported has produced；
2. whether meet PC1 ＞ PC2 or PC2 ＞ PC1
3. the state of sum；
4. the direction of transverter output current；
Inverter system controller realizes the logic of submodule on off state by being controlled to modulation degree M and phase angle γ Control, so as to control H bridge power units to export 9 kinds of different level, it is respectively：
Inverter system controller is based on CPU, realizes control via following steps：
Step 1：Read in AC system node, branch road, generator, transformer and reactive-load compensation parameter, and straight-flow system Node, branch parameters；
Step 2：Particle cluster algorithm parameter, including Population Size, maximum iteration, Studying factors, particle rapidity are set, With xd=[M(0), γ(0)] it is optimized variable, particle populations are initialized, put iterations k=0；Subscript(0)Represent the 0th iteration；
Step 3：Using prediction correction interior point to continuous variable xc=[PG (0), QR (0), Ud (0), Id (0), δ(0), Ps (0), Qs (0)] optimize, and assessed obtained result as the adaptive value of population individual, obtain the optimal value of object functionPGContributed for generated power, QRContributed for generator reactive, UdFor direct-current control voltage, IdFor DC control current, δ For the phase angle difference between AC and transverter side, Ps, QsThe respectively active power of AC, reactive power；
Step 4：Iterations k=k+1 is put, mutation operation is carried out to population population according to following two formula, obtained New xd=[M(k), γ(k)]；
Wherein, subscriptkRepresent kth time iteration；ω is angular frequency；For N-dimensional vector, i-th of particle during kth time iteration is represented In the position in N-dimensional space,viFor the vector of ion flight speed, PiThe desired positions that in optimizing space up to the present each particle is found are represented, PgRepresent the desired positions that up to the present all particles are found in whole colony；c1, c2For the arbitrary constant more than 0, difference table Show that particle flies to the acceleration weight of individual optimal solution and global solution；
Step 5：Using prediction correction interior point to continuous variable xc=[PG (k), QR (k), Ud (k), Id (k), δ(k), Ps (k), Qs (k)] optimize, and assessed obtained result as the adaptive value of population individual；
Step 6：Selected according to the adaptive value of former individual and experiment individual, preferentially enter the next generation, and more fresh target The optimal value of function
Step 7：Judge whether to reach maximum iteration, if so, then output result, exits circulation, otherwise go to step 4；
Variable after+1 iteration of kth is：
Wherein, x is independent variable；L, u is slack variable；Y, z, w are Lagrange multiplier；Symbol Δ represents difference； αpAnd αdIt is step-length, αpAnd αdSet respectively as follows：
Compared with prior art, inverter system of the present invention mainly has advantages below：
(1) by the single flying capacitor feed-in H-bridge unit of cascade, avoid load and be directly connected in inverter circuit Mains side midpoint；
(2) under same ac output voltage, voltage magnitude requirement of the present system to DC side power supply can reduce Half, and can only be realized by a DC source feed-in；
(3) requirement to inverter circuit is relatively low, and two low frequency switch cause the three-phase topological arrangement of inverter to become It is simpler.
Brief description of the drawings
Fig. 1 is the principle schematic of present system.
Embodiment
Fig. 1 is the principle schematic of filter system of the present invention.As shown in figure 1, the system include offshore wind turbine controller, AC system, inverter system controller in 9 level topology units, seashore；Wherein, offshore wind turbine controller and 9 level topology Unit is connected, and 9 level topology units are connected with AC system, inverter system controller on offshore wind turbine controller, seashore；Sea AC system is connected with 9 level topology units, inverter system controller on the bank, inverter system controller and 9 level topology AC system is connected on unit, seashore；9 level topology units include the flying capacitor C of offshore wind turbine DC sidedc, H bridge power lists Member 1, H bridge power units 2, submodule S1And submoduleSubmodule S6And submoduleWherein, H bridge power units 1 are by son Module S2, submodule S3, submoduleSubmoduleWith flying capacitor C1Composition, H bridge power units 2 are by submodule S4, submodule Block S5, submoduleSubmoduleWith flying capacitor C2Composition；The input signal of inverter system controller includes sea turn The voltage V of machine DC sideCdc, on seashore AC voltage Vg, on seashore AC electric current ig, suspend in H bridge power units 1 Electric capacity C1Voltage VC1And its reference valueFlying capacitor C in H bridge power units 22Voltage VC2And its reference value The active power of inverterAnd reactive powerThe output signal of inverter system controller is gate-control signal, for controlling 9 Submodule and electric capacity in level topology unit；In Fig. 1, rg、lgThe equivalent resistance and equivalent electric of AC respectively on seashore Sense；
The level number N of 9 level topology unit output voltageslevelIt can be determined by following formula
Nlevel=4Ncell+1
Wherein, NcellRepresent the H-bridge unit number of series connection；9 level topology units share six groups of complementary on off states, point It is not：
The capacitance voltage of H bridge power units remains at a given level, and its numerical value is determined by following formula
Wherein, n=1 ..., 6；
The numerical value C of flying capacitor can be determined by following formula
Wherein, IpkRepresent the peak value of load current；ΔVcRepresent ripple voltage；fswRepresent switching frequency；
The flying capacitor C of H bridge power units 11With the flying capacitor C of H bridge power units 22Meet lower relation of plane
C2=2C1
Flying capacitor C1、C2Unit voltage deviation be respectively PC1、PC2, can be determined by following formula
Wherein, VC1、VC2C is represented respectively1、C2Voltage；V represents the output electricity of H bridge power units It is flat；Work as PC1＞ PC2When, show VC1Deviation be more than VC2Deviation；
The charged state or discharge condition of electric capacity can be determined by following formula
If COMP1=1, then electric capacity C1Need to charge；If COMP1=0, then electric capacity C1Need to discharge；If COMP2= 1, then electric capacity C2Need to charge；If COMP2=0, then electric capacity C2Need to discharge；
The foundation that on off state corresponding to each level selects is as follows：
1. the voltage level exported has produced；
2. whether meet PC1 ＞ PC2 or PC2 ＞ PC1
3. the state of sum；
4. the direction of transverter output current；
Inverter system controller realizes the logic of submodule on off state by being controlled to modulation degree M and phase angle γ Control, so as to control H bridge power units to export 9 kinds of different level, it is respectively：
Inverter system controller is based on CPU, realizes control via following steps：
Step 1：Read in AC system node, branch road, generator, transformer and reactive-load compensation parameter, and straight-flow system Node, branch parameters；
Step 2：Particle cluster algorithm parameter, including Population Size, maximum iteration, Studying factors, particle rapidity are set, With xd=[M(0), γ(0)] it is optimized variable, particle populations are initialized, put iterations k=0；Subscript(0)Represent the 0th iteration；
Step 3：Using prediction correction interior point to continuous variable xc=[PG (0), QR (0), Ud (0), Id (0), δ(0), Ps (0), Qs (0)] optimize, and assessed obtained result as the adaptive value of population individual, obtain the optimal value of object functionPGContributed for generated power, QRContributed for generator reactive, UdFor direct-current control voltage, IdFor DC control current, δ For the phase angle difference between AC and transverter side, Ps, QsThe respectively active power of AC, reactive power；
Step 4：Iterations k=k+1 is put, mutation operation is carried out to population population according to following two formula, obtained New xd=[M(k), γ(k)]；
Wherein, subscriptkRepresent kth time iteration；ω is angular frequency；For N-dimensional vector, represent that i-th of particle exists during kth time iteration The position in N-dimensional space,viFor the vector of ion flight speed, PiThe desired positions that in optimizing space up to the present each particle is found are represented, PgRepresent the desired positions that up to the present all particles are found in whole colony；c1, c2For the arbitrary constant more than 0, difference table Show that particle flies to the acceleration weight of individual optimal solution and global solution；
Step 5：Using prediction correction interior point to continuous variable xc=[PG (k), QR (k), Ud (k), Id (k), δ(k), Ps (k), Qs (k)] optimize, and assessed obtained result as the adaptive value of population individual；
Step 6：Selected according to the adaptive value of former individual and experiment individual, preferentially enter the next generation, and more fresh target The optimal value of function
Step 7：Judge whether to reach maximum iteration, if so, then output result, exits circulation, otherwise go to step 4；
Variable after+1 iteration of kth is：
Wherein, x is independent variable；L, u is slack variable；Y, z, w are Lagrange multiplier；Symbol Δ represents difference； αpAnd αdIt is step-length, αpAnd αdSet respectively as follows：

Claims (1)

  1. A kind of 1. 9 new level offshore wind farm grid-connected inverter systems, it is characterised in that：The system controls including offshore wind turbine Device, 9 level topology units, AC system, inverter system controller on seashore；Wherein, offshore wind turbine controller is opened up with 9 level Flutter unit to be connected, 9 level topology units are connected with AC system, inverter system controller on offshore wind turbine controller, seashore； AC system is connected with 9 level topology units, inverter system controller on seashore, and inverter system controller is opened up with 9 level Flutter unit, AC system is connected on seashore；
    9 level topology units include the flying capacitor C of offshore wind turbine DC sidedc, H bridge power units 1, H bridge power units 2, son Module S1And submoduleSubmodule S6And submoduleWherein, H bridge power units 1 are by submodule S2, submodule S3, submodule BlockSubmoduleWith flying capacitor C1Composition, H bridge power units 2 are by submodule S4, submodule S5, submoduleSubmoduleWith flying capacitor C2Composition；
    The input signal of inverter system controller includes the voltage V of offshore wind turbine DC sideCdc, on seashore AC voltage Vg, on seashore AC electric current ig, flying capacitor C in H bridge power units 11Voltage VC1And its reference valueH bridge power Flying capacitor C in unit 22Voltage VC2And its reference valueThe active power of inverterAnd reactive powerInverter The output signal of system controller is gate-control signal, for controlling submodule and electric capacity in 9 level topology units；
    The level number N of 9 level topology unit output voltageslevelIt can be determined by following formula
    Nlevel=4Ncell+1
    Wherein, NcellRepresent the H-bridge unit number of series connection；9 level topology units share six groups of complementary on off states, are respectively：
    The capacitance voltage of H bridge power units remains at a given level, and its numerical value is determined by following formula
    <mrow> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mn>1</mn> </mrow> </msub> <mo>=</mo> <mfrac> <mi>V</mi> <mrow> <msup> <mn>2</mn> <mn>0</mn> </msup> <msub> <mi>N</mi> <mrow> <mi>c</mi> <mi>e</mi> <mi>l</mi> <mi>l</mi> </mrow> </msub> </mrow> </mfrac> <mo>,</mo> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mn>2</mn> </mrow> </msub> <mo>=</mo> <mfrac> <mi>V</mi> <mrow> <msup> <mn>2</mn> <mn>1</mn> </msup> <msub> <mi>N</mi> <mrow> <mi>c</mi> <mi>e</mi> <mi>l</mi> <mi>l</mi> </mrow> </msub> </mrow> </mfrac> <mo>,</mo> <mn>...</mn> <mo>,</mo> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mi>n</mi> </mrow> </msub> <mo>=</mo> <mfrac> <mi>V</mi> <mrow> <msup> <mn>2</mn> <mrow> <mi>n</mi> <mo>-</mo> <mn>1</mn> </mrow> </msup> <msub> <mi>N</mi> <mrow> <mi>c</mi> <mi>e</mi> <mi>l</mi> <mi>l</mi> </mrow> </msub> </mrow> </mfrac> </mrow>
    Wherein, n=1 ..., 6；
    The numerical value C of flying capacitor can be determined by following formula
    <mrow> <mi>C</mi> <mo>=</mo> <mfrac> <msub> <mi>I</mi> <mrow> <mi>p</mi> <mi>k</mi> </mrow> </msub> <mrow> <msub> <mi>&amp;Delta;V</mi> <mi>c</mi> </msub> <mo>&amp;times;</mo> <msub> <mi>f</mi> <mrow> <mi>s</mi> <mi>w</mi> </mrow> </msub> </mrow> </mfrac> </mrow>
    Wherein, IpkRepresent the peak value of load current；ΔVcRepresent ripple voltage；fswRepresent switching frequency；
    The flying capacitor C of H bridge power units 11With the flying capacitor C of H bridge power units 22Meet lower relation of plane
    C2=2C1
    Flying capacitor C1、C2Unit voltage deviation be respectively PC1、PC2, can be determined by following formula
    <mrow> <msub> <mi>P</mi> <mrow> <mi>C</mi> <mn>1</mn> </mrow> </msub> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>V</mi> <mrow> <mi>C</mi> <mn>1</mn> </mrow> <mrow> <mi>r</mi> <mi>e</mi> <mi>f</mi> </mrow> </msubsup> <mo>-</mo> <mo>|</mo> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mn>1</mn> </mrow> </msub> <mo>|</mo> </mrow> <mrow> <mo>|</mo> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mn>1</mn> </mrow> </msub> <mo>|</mo> </mrow> </mfrac> <mo>,</mo> <msub> <mi>P</mi> <mrow> <mi>C</mi> <mn>2</mn> </mrow> </msub> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>V</mi> <mrow> <mi>C</mi> <mn>2</mn> </mrow> <mrow> <mi>r</mi> <mi>e</mi> <mi>f</mi> </mrow> </msubsup> <mo>-</mo> <mo>|</mo> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mn>2</mn> </mrow> </msub> <mo>|</mo> </mrow> <mrow> <mo>|</mo> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mn>2</mn> </mrow> </msub> <mo>|</mo> </mrow> </mfrac> </mrow>
    Wherein, VC1、VC2C is represented respectively1、C2Voltage；V represents the output level of H bridge power units；When PC1＞ PC2When, show VC1Deviation be more than VC2Deviation；
    The charged state or discharge condition of electric capacity can be determined by following formula
    <mrow> <msub> <mi>COMP</mi> <mn>1</mn> </msub> <mo>=</mo> <msubsup> <mi>V</mi> <mrow> <mi>C</mi> <mn>1</mn> </mrow> <mrow> <mi>r</mi> <mi>e</mi> <mi>f</mi> </mrow> </msubsup> <mo>-</mo> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mn>1</mn> </mrow> </msub> <mo>,</mo> <msub> <mi>COMP</mi> <mn>2</mn> </msub> <mo>=</mo> <msubsup> <mi>V</mi> <mrow> <mi>C</mi> <mn>2</mn> </mrow> <mrow> <mi>r</mi> <mi>e</mi> <mi>f</mi> </mrow> </msubsup> <mo>-</mo> <msub> <mi>V</mi> <mrow> <mi>C</mi> <mn>2</mn> </mrow> </msub> </mrow>
    If COMP1=1, then electric capacity C1Need to charge；If COMP1=0, then electric capacity C1Need to discharge；If COMP2=1, then Electric capacity C2Need to charge；If COMP2=0, then electric capacity C2Need to discharge；
    The foundation that on off state corresponding to each level selects is as follows：
    1. the voltage level exported has produced；
    2. whether meet PC1＞ PC2Or PC2＞ PC1
    ③COMP1And COMP2State；
    4. the direction of transverter output current；
    Inverter system controller realizes the logic control of submodule on off state by being controlled to modulation degree M and phase angle γ System, so as to control H bridge power units to export 9 kinds of different level, it is respectively：- V,0,V；
    Inverter system controller is based on CPU, realizes control via following steps：
    Step 1：Reading AC system node, branch road, generator, transformer and reactive-load compensation parameter, and straight-flow system node, Branch parameters；
    Step 2：Particle cluster algorithm parameter, including Population Size, maximum iteration, Studying factors, particle rapidity are set, with xd =[M(0), γ(0)] it is optimized variable, particle populations are initialized, put iterations k=0；Subscript(0)Represent the 0th iteration；
    Step 3：Using prediction correction interior point to continuous variable xc=[PG (0), QR (0), Ud (0), Id (0), δ(0), Ps (0), Qs (0)] enter Row optimization, and assessed obtained result as the adaptive value of population individual, obtain the optimal value of object functionPG Contributed for generated power, QRContributed for generator reactive, UdFor direct-current control voltage, IdFor DC control current, δ is exchange Phase angle difference between side and transverter side, Ps, QsThe respectively active power of AC, reactive power；
    Step 4：Iterations k=k+1 is put, mutation operation is carried out to population population according to following two formula, obtains new xd =[M(k), γ(k)]；
    <mrow> <msubsup> <mi>v</mi> <mi>i</mi> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> </msubsup> <mo>=</mo> <msubsup> <mi>&amp;omega;v</mi> <mi>i</mi> <mi>k</mi> </msubsup> <mo>+</mo> <msub> <mi>c</mi> <mn>1</mn> </msub> <mrow> <mo>(</mo> <mrow> <msubsup> <mi>P</mi> <mi>i</mi> <mi>k</mi> </msubsup> <mo>-</mo> <msubsup> <mi>X</mi> <mi>i</mi> <mi>k</mi> </msubsup> </mrow> <mo>)</mo> </mrow> <mo>+</mo> <msub> <mi>c</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mrow> <msubsup> <mi>P</mi> <mi>g</mi> <mi>k</mi> </msubsup> <mo>-</mo> <msubsup> <mi>X</mi> <mi>i</mi> <mi>k</mi> </msubsup> </mrow> <mo>)</mo> </mrow> </mrow>
    <mrow> <msubsup> <mi>X</mi> <mi>i</mi> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> </msubsup> <mo>=</mo> <msubsup> <mi>X</mi> <mi>i</mi> <mi>k</mi> </msubsup> <mo>+</mo> <msubsup> <mi>v</mi> <mi>i</mi> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> </msubsup> </mrow>
    Wherein, subscript k represents kth time iteration；ω is angular frequency；For N-dimensional vector, represent that i-th of particle exists during kth time iteration The position in N-dimensional space,viFor the vector of ion flight speed, PiThe desired positions that in optimizing space up to the present each particle is found are represented, PgRepresent the desired positions that up to the present all particles are found in whole colony；c1, c2For the arbitrary constant more than 0, difference table Show that particle flies to the acceleration weight of individual optimal solution and global solution；
    Step 5：Using prediction correction interior point to continuous variable xc=[PG (k), QR (k), Ud (k), Id (k), δ(k), Ps (k), Qs (k)] enter Row optimization, and assessed obtained result as the adaptive value of population individual；
    Step 6：Selected according to the adaptive value of former individual and experiment individual, preferentially enter the next generation, and update object function Optimal value
    Step 7：Judge whether to reach maximum iteration, if so, then output result, exits circulation, otherwise go to step 4；
    Variable after+1 iteration of kth is：
    <mrow> <mfenced open = "[" close = "]"> <mtable> <mtr> <mtd> <msup> <mi>x</mi> <mrow> <mo>(</mo> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msup> <mi>l</mi> <mrow> <mo>(</mo> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msup> <mi>u</mi> <mrow> <mo>(</mo> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> <mo>)</mo> </mrow> </msup> </mtd> </mtr> </mtable> </mfenced> <mo>=</mo> <mfenced open = "[" close = "]"> <mtable> <mtr> <mtd> <msup> <mi>x</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msup> <mi>l</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msup> <mi>u</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mtd> </mtr> </mtable> </mfenced> <mo>+</mo> <msub> <mi>&amp;alpha;</mi> <mi>p</mi> </msub> <mfenced open = "[" close = "]"> <mtable> <mtr> <mtd> <mrow> <msup> <mi>&amp;Delta;x</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msup> <mi>&amp;Delta;l</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msup> <mi>&amp;Delta;u</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mrow> </mtd> </mtr> </mtable> </mfenced> </mrow> 2
    <mrow> <mfenced open = "[" close = "]"> <mtable> <mtr> <mtd> <msup> <mi>y</mi> <mrow> <mo>(</mo> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msup> <mi>z</mi> <mrow> <mo>(</mo> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msup> <mi>w</mi> <mrow> <mo>(</mo> <mrow> <mi>k</mi> <mo>+</mo> <mn>1</mn> </mrow> <mo>)</mo> </mrow> </msup> </mtd> </mtr> </mtable> </mfenced> <mo>=</mo> <mfenced open = "[" close = "]"> <mtable> <mtr> <mtd> <msup> <mi>y</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msup> <mi>z</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msup> <mi>w</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mtd> </mtr> </mtable> </mfenced> <mo>+</mo> <msub> <mi>&amp;alpha;</mi> <mi>d</mi> </msub> <mfenced open = "[" close = "]"> <mtable> <mtr> <mtd> <mrow> <msup> <mi>&amp;Delta;y</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msup> <mi>&amp;Delta;z</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msup> <mi>&amp;Delta;w</mi> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </msup> </mrow> </mtd> </mtr> </mtable> </mfenced> </mrow>
    Wherein, x is independent variable；L, u is slack variable；Y, z, w are Lagrange multiplier；Symbol Δ represents difference；αpAnd αd It is step-length, αpAnd αdSet respectively as follows：
    <mrow> <mtable> <mtr> <mtd> <mrow> <msub> <mi>&amp;alpha;</mi> <mi>p</mi> </msub> <mo>=</mo> <mn>0.9995</mn> <mrow> <mo>{</mo> <mrow> <munder> <mi>min</mi> <mi>i</mi> </munder> <mrow> <mo>(</mo> <mrow> <mfrac> <mrow> <mo>-</mo> <msub> <mi>l</mi> <mi>i</mi> </msub> </mrow> <mrow> <msub> <mi>&amp;Delta;l</mi> <mi>i</mi> </msub> </mrow> </mfrac> <mo>,</mo> <msub> <mi>&amp;Delta;l</mi> <mi>i</mi> </msub> <mo>&lt;</mo> <mn>0</mn> <mo>;</mo> <mfrac> <mrow> <mo>-</mo> <msub> <mi>u</mi> <mi>i</mi> </msub> </mrow> <mrow> <msub> <mi>&amp;Delta;u</mi> <mi>i</mi> </msub> </mrow> </mfrac> <mo>,</mo> <msub> <mi>&amp;Delta;u</mi> <mi>i</mi> </msub> <mo>&lt;</mo> <mn>0</mn> </mrow> <mo>)</mo> </mrow> <mo>,</mo> <mn>1</mn> </mrow> <mo>}</mo> </mrow> </mrow> </mtd> </mtr> <mtr> <mtd> <mrow> <msub> <mi>&amp;alpha;</mi> <mi>d</mi> </msub> <mo>=</mo> <mn>0.9995</mn> <mrow> <mo>{</mo> <mrow> <munder> <mi>min</mi> <mi>i</mi> </munder> <mrow> <mo>(</mo> <mrow> <mfrac> <mrow> <mo>-</mo> <msub> <mi>z</mi> <mi>i</mi> </msub> </mrow> <mrow> <msub> <mi>&amp;Delta;z</mi> <mi>i</mi> </msub> </mrow> </mfrac> <mo>,</mo> <msub> <mi>&amp;Delta;z</mi> <mi>i</mi> </msub> <mo>&lt;</mo> <mn>0</mn> <mo>;</mo> <mfrac> <mrow> <mo>-</mo> <msub> <mi>w</mi> <mi>i</mi> </msub> </mrow> <mrow> <msub> <mi>&amp;Delta;w</mi> <mi>i</mi> </msub> </mrow> </mfrac> <mo>,</mo> <msub> <mi>&amp;Delta;w</mi> <mi>i</mi> </msub> <mo>&lt;</mo> <mn>0</mn> </mrow> <mo>)</mo> </mrow> <mo>,</mo> <mn>1</mn> </mrow> <mo>}</mo> </mrow> </mrow> </mtd> </mtr> </mtable> <mo>.</mo> </mrow> 3
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110829478A (en) * 2019-10-30 2020-02-21 浙江大学 Low-frequency alternating-current uncontrolled rectification power transmission system of offshore wind power plant
CN111668884A (en) * 2020-06-30 2020-09-15 国电联合动力技术有限公司 Wind power plant voltage regulation iterative learning control method and device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110829478A (en) * 2019-10-30 2020-02-21 浙江大学 Low-frequency alternating-current uncontrolled rectification power transmission system of offshore wind power plant
CN111668884A (en) * 2020-06-30 2020-09-15 国电联合动力技术有限公司 Wind power plant voltage regulation iterative learning control method and device
CN111668884B (en) * 2020-06-30 2022-10-25 国电联合动力技术有限公司 Iterative learning control method and device for voltage regulation of wind power plant

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