CN103178550B - Three-phase swarm micro-inverter system with cluster adjuster and control method - Google Patents

Three-phase swarm micro-inverter system with cluster adjuster and control method Download PDF

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Publication number
CN103178550B
CN103178550B CN201310138141.5A CN201310138141A CN103178550B CN 103178550 B CN103178550 B CN 103178550B CN 201310138141 A CN201310138141 A CN 201310138141A CN 103178550 B CN103178550 B CN 103178550B
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micro
inverter
phase
control
power
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CN103178550A (en
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杨建�
阮璇
粟梅
范辉
张鹏
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JIANGXI Z-ENERGY ELECTRIC TECHNOLOGY CO., LTD.
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Jiangxi Zhongneng Electrical Science & Technology Co Ltd
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy
    • Y02E10/56Power conversion systems, e.g. maximum power point trackers
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/50Arrangements for eliminating or reducing asymmetry in polyphase networks

Abstract

The invention discloses a three-phase swarm micro-inverter system with a cluster adjuster and a control method. A micro grid-connected inverter is sensitively controlled by arranging a constant swarm micro-inverter and a free swarm micro-inverter, and meanwhile, the cost is reduced; the cluster adjuster uses a particle swarm algorithm as a power algorithm, so that the power balance is adjusted and the power consumption is reduced; double-level distribution type control is used, so that the micro-inverters exchange information through a local communication network, the cluster adjuster does not need to control each micro-inverter to switch, and the long-distance communication and the cost consumption can be reduced; and when each-phase input power is varied, the entire working efficiency of the micro-inverter can be ensured by switching a sub swarm of the free swarm micro-inverter. The control method is easy to realize, so that the adverse effect on entire current output, caused by the problems that a photovoltaic cell array can not illuminate in a balanced manner, certain photovoltaic cells are damaged and the like, can be effectively solved.

Description

There is the micro-inverter system of three-phase group and the control method of cluster adjuster
Technical field
The present invention relates to have the micro-inverter system of three-phase group and the control method of cluster adjuster.
Background technology
Solar energy is clean pollution-free and inexhaustible, nexhaustible, the energy that is available anywhere, in fossil energy today of shortage gradually, select solar energy as an alternative the energy be one of effective way solving energy crisis.The general crossover tool of micro-inverter as DC-AC that adopt of photovoltaic generating system.
In engineering practice, the unsuitable too much serial or parallel connection of photovoltaic cell, so most of photovoltaic system adopts many micro-inverter parallels, replace a large-scale inverter, and photovoltaic battery array of every micro-inverter connection can improve the adverse effect to overall grid such as photovoltaic battery array uneven illumination, indivedual faults.When three-phase grid, traditional method is every similar number, micro-inverter that structure is identical of all adopting mutually, realizes relatively easily power-balance, but in the time that each phase external condition is different, easily causes certain micro-inverter in mutually too much idle.
In many micro-grid-connected inverters systems, if micro-inverter is fixed mean allocation in electrical network three-phase, although easily control, the utilance of micro-inverter is restricted, topological underaction; If micro-inverter all can freely work in electrical network arbitrarily mutually in, can make to control cost too high; Therefore be badly in need of proposing a kind of new solar energy three-phase micro-inverter system and control method thereof, reduce power loss, improve the operating efficiency of micro-inverter.
Summary of the invention
The present invention proposes to have the micro-inverter system of three-phase group and the control method of cluster adjuster, its object is, overcome above-mentioned the deficiencies in the prior art, by the micro-inverter of group of stability and free group is set, utilize cluster adjuster to control, ensure three-phase power balance, reduce power loss, improve micro-inverter operating efficiency.
There is the micro-inverter system of photovoltaic three-phase group of cluster adjuster, comprise cluster adjuster, micro-inverter group, communication circuit module and testing circuit module, micro-inverter group's direct-flow input end is all connected with testing circuit module with ac output end, the output of testing circuit module is connected with cluster adjuster, and cluster adjuster connects by communication module and the micro-inverter faciation of free group;
Described micro-inverter group comprises 4 groups of single-phase micro-inverters, is divided into the micro-inverter of group of stability and the micro-inverter of free group; Wherein three groups of single-phase micro-inverters are that the mutually micro-inverter group of the mutually micro-inverter group of A, the mutually micro-inverter group of B and C forms the micro-inverter of group of stability, and another group is the micro-inverter of free group; In micro-inverter group, the DC terminal of each single-phase micro-inverter is connected with a photovoltaic battery array output;
In the micro-inverter of each group of stability, the quantity of single-phase micro-inverter is identical, the interchange end that A fixes each single-phase micro-inverter in group is connected mutually with electrical network A, the interchange end that B fixes each single-phase micro-inverter in group is connected with electrical network B, and the interchange end that C fixes each single-phase micro-inverter in group is connected mutually with electrical network C;
In the micro-inverter of free group, the interchange end of each single-phase micro-inverter, by selecting control switch to be connected with electrical network is arbitrary, is connected by telecommunication circuit unit between each single-phase micro-inverter in the micro-inverter of free group;
The micro-inverter of free group forms 1~3 subgroup voluntarily, and subgroup group topology has dynamic; The micro-inverter of free group needs supplementary power number to queue up at A, B and C three-phase voluntarily according to every mutually, in every phase subgroup to cluster adjuster power information micro-inverter of being read as node, in the time that the power sum of micro-inverter in queue reaches this phase demand, the micro-inverter of node stops queuing up and sending cohort to cluster adjuster completing information, and cluster adjuster is confirmed cohort.
Each single-phase micro-inverter in described micro-inverter group all adopts interleaving inverse excitation type structure.
Each single-phase micro-inverter in described micro-inverter group also comprises control unit, testing circuit unit and telecommunication circuit unit;
Single-phase micro-inverter in the micro-inverter of free group carries out the power line carrier, PLC based on token mechanism by telecommunication circuit unit separately.
There is the control method of the micro-inverter system of photovoltaic three-phase group of cluster adjuster, adopt the described micro-inverter system of photovoltaic three-phase group with cluster adjuster, adopt two-stage distributed control, power output and loss power when the calculating that adopts particle cluster algorithm to calculate as power optimization algorithm by cluster adjuster respectively balances each other, control the power output of the micro-inverter in each phase subgroup in the micro-inverter group of free group, regulate three-phase power balance, reduce power loss;
Described two-stage distributed control comprises high-rise control and bottom control, and its control on the middle and senior level refers to by cluster adjuster selects in the micro-inverter of free group the subgroup three-phase that is connected to the grid respectively according to the power output that respectively fixes group in the micro-inverter of group of stability;
Bottom control refers to the communication network forming between the control algolithm of each single-phase micro-inverter inside and single-phase micro-inverter; The control algolithm of single-phase micro-inverter inside comprises operating efficiency control, also comprises MPPT control of the prior art, sharing control, current loop control and phase-locked loop (PLL) control; The communication network forming between single-phase micro-inverter refers to that in the micro-inverter of free group, each single-phase micro-inverter intercoms mutually by communication unit separately, obtain power output and operating state separately, the power output that respectively fixes the micro-inverter of group of sending according to cluster adjuster is carried out independent assortment, builds the micro-inverter of free group subgroup.
The operating efficiency control procedure of each single-phase micro-inverter is as follows:
Step 1: the output voltage of the photovoltaic battery array that each single-phase micro-inverter collection is connected with itself is as input voltage;
Step 2: by calculating each single-phase micro-inverter input voltage and setting voltage U minratio, judge the operating efficiency of each single-phase micro-inverter;
Step 3: redefine micro-inverter switching situation; When single-phase micro-inverter input voltage is lower than U mintime, if micro-inverter, in the work that has been connected to the grid of input state, quits work voluntarily and being connected of cut-out and electrical network, if micro-inverter, in dissengaged positions, keeps present situation; When single-phase micro-inverter input voltage is higher than U mintime, if micro-inverter, in dissengaged positions, is started working voluntarily and accesses electrical network, if micro-inverter is in input state, keep present situation.
Described cluster adjuster adopts particle cluster algorithm as power optimization algorithm, calculates power output and loss power while respectively balancing each other, wherein, the target function of particle cluster algorithm, adaptive value function is T, reaches minimum value as controlling target using T:
T=k 1P cost+k 2ΔP s
Wherein, P costfor power loss: P cost=(P inA+ P inB+ P inC)-(P outA+ P outB+ P outC), Δ P sfor three-phase equilibrium expression formula: Δ P s=(P outA-P outB) 2+ (P outB-P outC) 2+ (P outC-P outA) 2, for the power output summation of the mutually micro-inverter of A, for the power output summation of the mutually micro-inverter of B, for the power output summation of the mutually micro-inverter of C, for the input power summation of the mutually micro-inverter of A, for the input power summation of the mutually micro-inverter of B, for the input power summation of the mutually micro-inverter of C, k 1, k 2be respectively P costwith Δ P scoefficient, 0<k 1<k 2<1;
Particle cluster algorithm model is as follows:
v i(t)=wv i(t-1)+c 1r 1(p i-x i(t-1))+c 2r 2(p g-x i(t-1))????(1)
x i(t)=v i(t)+x i(t-1)??????????????????????(2)
In formula, x ifor particle position; v ifor flying speed of partcles; W is inertia weight; c 1, c 2for acceleration factor; r 1, r 2for the random number in [0,1] range; Pi is the position of individual optimal particle; p gfor the position of global optimum's particle;
With P outA, P outB, P outCand P inA, P inB, P inCthe sextuple space forming is as the location finding space of particle, and particle population number is N, and iterations is M;
Random initializtion population particle position and flying speed, make w=0.9, c 1=c 2=0.5; Relatively particle current location and this particle live through desired positions p iadaptive value, if the adaptive value of particle current location is less than individual desired positions p iadaptive value, replace p with current particle position i; More individual optimum particle position p iwith the particle position p of global optimum gadaptive value, if p iadaptive value be less than p gadaptive value, p igive p g; Recalculate particle position and speed according to formula (1) and formula (2), if reach stopping criterion for iteration or iterations, stop iteration, current solution is optimal solution iteration wherein, end condition is:
| x &RightArrow; i - x &RightArrow; i - 1 | max | x &RightArrow; i | < A
for ultimate range between particle, A is given particle range difference Percentage Criterion, gets A=0.05.
Described single-phase micro-inverter is 200W.
Beneficial effect
The invention provides the micro-inverter system of three-phase group and the control method with cluster adjuster, by the micro-inverter of group of stability and free group is set, realize the flexible control to grid-connected micro-inverter, make cost simultaneously; Utilize cluster adjuster to adopt particle cluster algorithm as power algorithm, regulating power balance, reduces power loss; Adopt two-stage distributed control, between each micro-inverter, pass through local communication network exchange message, cluster adjuster does not need each micro-inverter switching to control, long haul communication and cost consumption are reduced, in the time that each phase input power changes, the micro-inverter of switching free group subgroup can ensure micro-inverter whole work efficiency, and the method is easy to realize, and effectively solves the problems such as the uneven and indivedual damages of photovoltaic battery array illumination and overall current is exported to the adverse effect causing.
Brief description of the drawings
Fig. 1 is the micro-inverter system structural representation of photovoltaic three-phase group of the present invention;
Fig. 2 is the micro-inverter system free group of photovoltaic three-phase group of the present invention structural representation;
Fig. 3 is the control schematic diagram of the micro-inverter system cluster of photovoltaic three-phase group of the present invention adjuster to A, B, C three-phase;
Fig. 4 is the micro-inverter local communication of the micro-inverter system free group of photovoltaic three-phase group of the present invention and dynamic cohort schematic diagram;
Fig. 5 is the micro-inverter system group of stability of photovoltaic three-phase group of the present invention and free group work schematic diagram;
Fig. 6 is the micro-inverter system control flow chart of photovoltaic three-phase group of the present invention;
Fig. 7 is the micro-inverter system interleaving inverse excitation of the photovoltaic three-phase group of the present invention inverter structure figure that declines.
Embodiment
Below in conjunction with accompanying drawing, the present invention will be further described.
Fig. 1 is the micro-inverter system structural representation of photovoltaic three-phase group of the present invention.As shown in the figure, a kind of micro-inverter system of photovoltaic three-phase group (100) with cluster adjuster, comprise cluster adjuster (103), micro-inverter group, communication circuit module and testing circuit module, micro-inverter group's direct-flow input end is all connected with testing circuit module with ac output end, detection signal input cluster adjuster, cluster adjuster connects by communication module and the micro-inverter faciation of free group;
Described micro-inverter group comprises 4 groups of single-phase micro-inverters, is converted to alternating current for the direct current that photovoltaic battery array 105 is produced, and is divided into the micro-inverter of group of stability and the micro-inverter of free group; Wherein three groups of single-phase micro-inverters wherein three groups of single-phase micro-inverters be that the mutually micro-inverter group of the mutually micro-inverter group of A, the mutually micro-inverter group of B and C forms the micro-inverter of group of stability, another group is the micro-inverter of free group; In micro-inverter group, the DC terminal of each single-phase micro-inverter is connected with a photovoltaic battery array (105) output;
In each group of stability, the quantity of single-phase micro-inverter is identical, the interchange end that A fixes each single-phase micro-inverter in group is connected mutually with electrical network (101) A, the interchange end that B fixes each single-phase micro-inverter in group is connected with electrical network (101) B, and the interchange end that C fixes each single-phase micro-inverter in group is connected mutually with electrical network (101) C;
In the micro-inverter of free group, the interchange end of each single-phase micro-inverter is connected by selector switch and electrical network are arbitrary, in the micro-inverter of free group, between each single-phase micro-inverter, is connected by telecommunication circuit.
Each single-phase micro-inverter all adopts interleaving inverse excitation type structure, and as shown in Figure 7, interleaving inverse excitation translation circuit carries out DC-dc conversion, and inverter bridge is carried out DC-AC conversion, alternating current input electrical network.
Cluster adjuster (103), for regulating three-phase power balance, reduces power loss.
The micro-inverter of group of stability (102) is divided into A phase, B phase and 3 group of stabilitys 102 of C phase and free group 104, micro-inverter number in group of stability is more, location distribution freedom and flexibility, decide installation site in its sole discretion by user, micro-inverter number in free group is less, concentrate in its geographical position, and unified plan is in the good place of illumination condition.Group of stability steady job is in A, B, C three-phase, the contained micro-inverter number of each group of stability equates, number is determined by user's request, can from dozens of to thousands of not etc., and micro-inverter in free group can form 1~3 subgroup voluntarily, it exchanges holds a certain being connected dynamic and in electrical network, fixing, determines by cluster adjuster 103 which phase free group subgroup works in.
For example: if each micro-inverter rated output power is 200W, user's request is every phase 4kW, group of stability can be established 20 micro-inverters of every phase, considers and is not that each micro-inverter is operated in specified situation, can separately establish and in free group, have 30 micro-inverters.
Fig. 2 is the micro-inverter system free group of photovoltaic three-phase group of the present invention structural representation.As shown in the figure, every micro-inverter of multiple freedom that comprises mutually, micro-inverter number that the every phase free group of different time subgroup is contained may be different, and their output is in parallel with group of stability, its output final input electrical network (101).
Between the adjacent micro-inverter of several free groups, form local communication network, according to self power output, three-phase Difference of Output Power and power loss variations situation, in A phase free group subgroup (1041), freely micro-inverter 1, free micro-inverter 2 form one with free micro-inverter 3 and can make up the mutually under powered subgroup of A, subgroup by cluster adjuster is distributed, and they work in A phase.If A needs to compensate 800W power mutually, the micro-inverter 1 of freedom, freely micro-inverter 2 and the total output of freely micro-inverter 3 in A phase free group subgroup (1041) only have 600W, be not enough to compensate A phase power, and freely micro-inverter n power output is 200W, installation site is near above three micro-inverters, micro-inverter n also can form subgroup with them, and co-operation is in A phase.If A does not need freely micro-inverter n mutually, and B needs 200W power back-off mutually, and it will work in B phase after will forming B phase free group subgroups (1042) with other micro-inverters.
The micro-inverter of each freedom all can work in A phase, B phase or C phase, and actual often all may have free group subgroup in work in mutually, may a fewly there is no mutually free group subgroup in work yet, and be not that the micro-inverter of each freedom is worked, this depends on the whether factor such as balance of the size of input power and power.
No matter be free group or group of stability, each micro-inverter also should comprise control unit (1046), testing circuit unit (1045) and telecommunication circuit unit (1044), control unit (1046) is cluster adjuster not, but each single-phase micro-inverter island effect, the control centre of sharing control etc., the each micro-inverter operating efficiency of this control unit control, and the control circuit unit of the micro-inverter of free group receives the control command from cluster adjuster, collect adjacent micro-inverter input power and power output breath by telecommunication circuit unit, control the local communication between micro-inverter.
Fig. 3 is the control schematic diagram of the micro-inverter system cluster of photovoltaic three-phase group of the present invention adjuster to A, B and C three-phase.As shown in the figure, the mutually micro-inverter group of A (301), the mutually micro-inverter group of B (302), the mutually micro-inverter group of C (303) are the set that respectively fixes group and free group subgroup.Cluster adjuster (103) gathers each phase input voltage, output voltage, input current and output current by communication module, calculate three-phase input power and power output, and judge on this basis power-balance situation and the power loss situation of current three-phase, while is sent switching instruction to the free group in electrical network, supplemented the deficiency of group of stability by free group, final balance three phase power, reduces power loss.
The micro-inverter system of photovoltaic three-phase group adopts two-stage distributed control strategy to control micro-inverter, bottom control is that the communication between the micro-inverter of control unit free group of each micro-inverter inside realizes, and high-rise control is the control network of cluster adjuster to micro-inverter.Communication network between the micro-inverter of free group contains a lot of global nodes, the each micro-inverter of free group all can be used as node, but in the group of each spontaneous formation, only have one at first to cluster adjuster power information micro-inverter of being read as node, cluster adjuster is by the micro-inverter of these global node controls subgroup.So cluster adjuster does not need to obtain the communication information between micro-inverter, do not need each micro-inverter to control yet, the information such as the micro-inverter operating state of group, power output that only need to gain freedom from node, to automatically the micro-inverter group of cohort carry out grid-connected switching control.
What cluster adjuster adopted the control of the micro-inverter system of three-phase group and adjusting is particle cluster algorithm.
Whole system also comprises testing circuit module (1031) and communication circuit module (1032), testing circuit module is for providing each phase input voltage, output voltage, input current and output current to the adjuster of trooping, and the communication circuit module adjuster that is used for trooping sends control command to outside.As shown in the figure, testing circuit and telecommunication circuit are connected between micro-inverter and cluster adjuster, belong to common circuit.
Fig. 4 is the micro-inverter local communication of the micro-inverter system free group of photovoltaic three-phase group of the present invention and dynamic cohort schematic diagram.As shown in the figure, taking 4 micro-inverters as example, for guaranteeing that the control information of cluster adjuster all arrives each micro-inverter, the local communication between micro-inverter is very important, adopts the power line carrier, PLC based on token mechanism between the micro-inverter of free group.The micro-inverter of free group is by providing every performance number that needs mutually compensation of power output, operation information and the output of cluster adjuster separately, automatically carry out cohort, because micro-inverter free group topology is along with the variation of above-mentioned condition changes, so the communication network between micro-inverter is different and change in time, the cohort topology between micro-inverter is dynamic; Wherein whether operation information refers to the micro-inverter work of individual event.If micro-inverter 4 in Fig. 4 (a) is to micro-inverter 3 transmitted powers and operation information, in Fig. 4 (b), micro-inverter 4 is to micro-inverter 2 and micro-inverter 3 transmitted powers and operation information, micro-inverter 4 and the mutual transmitted power of micro-inverter 3 and operation information in Fig. 4 (c); In Fig. 4 (a), micro-inverter 1 and micro-inverter 2 combine, and in Fig. 4 (b), micro-inverter 2 and micro-inverter 3 combine, and in Fig. 4 (c), micro-inverter 1, micro-inverter 2 and micro-inverter 3 combine.
Which in three phase network of each group work by cluster adjuster according to three-phase power balance situation and power loss situation Comprehensive Control.Communication between micro-inverter belongs to the bottom control of the distributed control of secondary, and bottom communication is not subject to high-rise control effect.Micro-inverter does not need with other each micro-inverter or the high-rise network of controlling to communicate, and only need carry out operation conditions relatively by the micro-inverter closing on it.
Whether micro-inverter i can receive the control signal of cluster adjuster or the power of other micro-inverters and operation information, depend on the current topology of micro-inverter i group communication network of living in, so in the group of each spontaneous formation, all have one at first to cluster adjuster power information micro-inverter of being read as global node, directly collect the control signal of group's adjuster.
Fig. 5 is the micro-inverter system group of stability of photovoltaic three-phase group of the present invention and free group work schematic diagram.As shown in the figure, suppose that A fixes four photovoltaic battery arrays (grey color part) of group in (1021) because uneven illumination or failure and other reasons cause this phase power output to reduce, thereby likely cause three-phase power imbalance, now in free group (104), four micro-inverters of subgroup A drop into A phase electrical network under the control of cluster adjuster, make up the deficiency that A exports mutually.Meanwhile, B fixes the deficiency that group (1022) and C fix group (1023) and is also made up by the subgroup B in free group (104) and subgroup C.In the time that next control cycle arrives, these micro-inverters that are respectively used to supplementary A, B, C three-phase solid grouping may turn to and work in other two-phases, or do not work.
The control flow chart that Fig. 6 (a) is the each micro-inverter operating efficiency of the micro-inverter system of photovoltaic three-phase group of the present invention.As shown in the figure, the method comprises:
Execution step a601, the output voltage of the photovoltaic battery array that each single-phase micro-inverter collection is connected with itself is as input voltage; ;
Execution step a602, by calculating each single-phase micro-inverter input voltage and setting voltage U minratio, judge the operating efficiency of each single-phase micro-inverter, U min=20V;
Execution step a603, redefines micro-inverter switching situation; When single-phase micro-inverter input voltage is lower than U mintime, if micro-inverter, in the work that has been connected to the grid of input state, quits work voluntarily and being connected of cut-out and electrical network, if micro-inverter, in dissengaged positions, keeps present situation; When single-phase micro-inverter input voltage is higher than U mintime, if micro-inverter, in dissengaged positions, is started working voluntarily and accesses electrical network, if micro-inverter is in input state, keep present situation.
Fig. 6 (b) is photovoltaic three-phase group micro-inverter system power adjustments control of the present invention and grid-connected flow chart.As shown in the figure, the method comprises:
Execution step b601, the direct current that micro-inverter change-over circuit produces photovoltaic battery array is converted to alternating current;
Execution step b602, cluster adjuster is confirmed micro-inverter number of every phase free group subgroup from cohort situation according to particle cluster algorithm result of calculation and free group;
Execution step b603, the subgroup of free group is dropped into respectively electrical network three-phase by cluster adjuster;
Execution step b604, the each phase electrical network of input after the alternating current of multiple micro-inverter outputs is merged.
In Fig. 6 (b), cluster adjuster adopts particle cluster algorithm as power optimization algorithm, and while calculating three-phase equilibrium, the lowest loss power of each phase, realizes the target that three-phase power balance and power loss are minimum.
At definite target function T=k 1p cost+ k 2Δ P s, k 1=0.4, k 2under=0.6 prerequisite, first crowd quantity N=30 is set, iterations M=60, inertia weight w=0.9, accelerator coefficient c 1=c 2=0.5, then according to adaptive value function
v i(t)=wv i(t-1)+c 1r 1(p i-x i(t-1))+c 2r 2(p g-x i(t-1))
x i(t)=v i(t)+x i(t-1)
Read particle rapidity v iwith position x i, the position p of more individual optimal particle iposition p with global optimum's particle gthe value row iteration of going forward side by side, finally judge whether to find optimal solution by (getting A=0.05) if so, export optimal solution, otherwise continue iterative computation until reach maximum iteration time.
Iteration obtains optimum input-output power after, cluster adjuster current system input-output power with compare, obtain difference then in conjunction with the power information of the micro-inverter fed of free group, determine the free group subgroup that need to drop into every phase, and the micro-inverter of global node in subgroup sends instruction, instruction is transmitted to other micro-inverters by local communication network, remaining micro-inverter corresponding actions in each group, drop into corresponding A, B, C phase electrical network, coordinated three-phase power balance, control target that power loss is minimum.For example: reduce 600W if A fixes group power output, cause three-phase power imbalance, cluster adjuster sends after this information to free group, the micro-inverter that is 200W by 3 power outputs in free group forms a subgroup and feeds back to cluster adjuster, cluster adjuster is confirmed and micro-these three free groups inverter is dropped into A phase electrical network, thereby it is not enough mutually to have made up A.

Claims (6)

1. there is the micro-inverter system of photovoltaic three-phase group of cluster adjuster, it is characterized in that, comprise cluster adjuster, micro-inverter group, communication circuit module and testing circuit module, micro-inverter group's direct-flow input end is all connected with testing circuit module with ac output end, the output of testing circuit module is connected with cluster adjuster, and cluster adjuster connects by communication module and the micro-inverter faciation of free group;
Described micro-inverter group comprises 4 groups of single-phase micro-inverters, is divided into the micro-inverter of group of stability and the micro-inverter of free group; Wherein three groups of single-phase micro-inverters are that the mutually micro-inverter group of the mutually micro-inverter group of A, the mutually micro-inverter group of B and C forms the micro-inverter of group of stability, and another group is the micro-inverter of free group; In micro-inverter group, the DC terminal of each single-phase micro-inverter is connected with a photovoltaic battery array output;
In the micro-inverter of each group of stability, the quantity of single-phase micro-inverter is identical, the interchange end that A fixes each single-phase micro-inverter in group is connected mutually with electrical network A, the interchange end that B fixes each single-phase micro-inverter in group is connected with electrical network B, and the interchange end that C fixes each single-phase micro-inverter in group is connected mutually with electrical network C;
In the micro-inverter of free group, the interchange end of each single-phase micro-inverter, by selecting control switch to be connected with electrical network is arbitrary, is connected by telecommunication circuit unit between each single-phase micro-inverter in the micro-inverter of free group;
The micro-inverter of free group forms 1~3 subgroup voluntarily, and subgroup group topology has dynamic; The micro-inverter of free group needs supplementary power number to queue up at A, B and C three-phase voluntarily according to every mutually, in every phase subgroup to cluster adjuster power information micro-inverter of being read as node, in the time that the power sum of micro-inverter in queue reaches this phase demand, the micro-inverter of node stops queuing up and sending cohort to cluster adjuster completing information, and cluster adjuster is confirmed cohort.
2. the micro-inverter system of photovoltaic three-phase group with cluster adjuster according to claim 1, is characterized in that, the each single-phase micro-inverter in described micro-inverter group all adopts interleaving inverse excitation type structure.
3. according to the micro-inverter system of photovoltaic three-phase group with cluster adjuster described in claim 1 or 2 any one, it is characterized in that, the each single-phase micro-inverter in described micro-inverter group also comprises control unit, testing circuit unit and telecommunication circuit unit;
Single-phase micro-inverter in the micro-inverter of free group carries out the power line carrier, PLC based on token mechanism by telecommunication circuit unit separately.
4. there is the control method of the micro-inverter system of photovoltaic three-phase group of cluster adjuster, it is characterized in that, the micro-inverter system of photovoltaic three-phase group with cluster adjuster described in employing claim 1-3, adopt two-stage distributed control, adopt particle cluster algorithm to calculate power output and the loss power while respectively balancing each other as power optimization algorithm by cluster adjuster, control the power output of the micro-inverter in each phase subgroup in the micro-inverter group of free group, regulate three-phase power balance;
Described two-stage distributed control comprises high-rise control and bottom control, and its control on the middle and senior level refers to by cluster adjuster selects in the micro-inverter of free group the subgroup three-phase that is connected to the grid respectively according to the power output that respectively fixes group in the micro-inverter of group of stability;
Bottom control refers to the communication network forming between the control algolithm of each single-phase micro-inverter inside and single-phase micro-inverter; The control algolithm of single-phase micro-inverter inside comprises operating efficiency control; The communication network forming between single-phase micro-inverter refers to that in the micro-inverter of free group, each single-phase micro-inverter intercoms mutually by communication unit separately, obtain power output and operating state separately, the power output that respectively fixes the micro-inverter of group of sending according to cluster adjuster is carried out independent assortment, builds the micro-inverter of free group subgroup.
5. the control method of the micro-inverter system of photovoltaic three-phase group with cluster adjuster according to claim 4, is characterized in that, the operating efficiency control procedure of each single-phase micro-inverter is as follows:
Step 1: the output voltage of the photovoltaic battery array that each single-phase micro-inverter collection is connected with itself is as input voltage;
Step 2: by calculating each single-phase micro-inverter input voltage and setting voltage U minratio, judge the operating efficiency of each single-phase micro-inverter;
Step 3: redefine micro-inverter switching situation; When single-phase micro-inverter input voltage is lower than U mintime, if micro-inverter, in the work that has been connected to the grid of input state, quits work voluntarily and being connected of cut-out and electrical network, if micro-inverter, in dissengaged positions, keeps present situation; When single-phase micro-inverter input voltage is higher than U mintime, if micro-inverter, in dissengaged positions, is started working voluntarily and accesses electrical network, if micro-inverter is in input state, keep present situation.
6. the control method of the micro-inverter system of photovoltaic three-phase group with cluster adjuster according to claim 4, it is characterized in that, described cluster adjuster adopts particle cluster algorithm as power optimization algorithm, calculate power output and loss power while respectively balancing each other, wherein, the target function of particle cluster algorithm, adaptive value function is T, reaches minimum value as controlling target using T:
T=k 1P cost+k 2ΔP s
Wherein, P costfor power loss: P cost=(P inA+ P inB+ P inC)-(P outA+ P outB+ P outC), Δ P sfor three-phase equilibrium expression formula: Δ P s=(P outA-P outB) 2+ (P outB-P outC) 2+ (P outC-P outA) 2, for the power output summation of the mutually micro-inverter of A, for the power output summation of the mutually micro-inverter of B, for the power output summation of the mutually micro-inverter of C, for the input power summation of the mutually micro-inverter of A, for the input power summation of the mutually micro-inverter of B, for the input power summation of the mutually micro-inverter of C, k 1, k 2be respectively P costwith Δ P scoefficient, 0<k 1<k 2<1;
Particle cluster algorithm model is as follows:
v i(t)=wv i(t-1)+c 1r 1(p i-x i(t-1))+c 2r 2(p g-x i(t-1))????(1)
x i(t)=v i(t)+x i(t-1)????????????????????(2)
In formula, x ifor particle position; v ifor flying speed of partcles; W is inertia weight; c 1, c 2for acceleration factor; r 1, r 2for the random number in [0,1] range; p ifor the position of individual optimal particle; p gfor the position of global optimum's particle;
With P outA, P outB, P outCand P inA, P inB, P inCthe sextuple space forming is as the location finding space of particle, and particle population number is N, and iterations is M;
Random initializtion population particle position and flying speed, make w=0.9, c 1=c 2=0.5; Relatively particle current location and this particle live through desired positions p iadaptive value, if the adaptive value of particle current location is less than individual desired positions p iadaptive value, replace p with current particle position i; More individual optimum particle position p iwith the particle position p of global optimum gadaptive value, if p iadaptive value be less than p gadaptive value, p igive p g; Recalculate particle position and speed according to formula (1) and formula (2), if reach stopping criterion for iteration or iterations, stop iteration, current solution is optimal solution iteration wherein, end condition is:
| x &RightArrow; i - x &RightArrow; i - 1 | max | x &RightArrow; i | < A
for ultimate range between particle, A is given particle range difference Percentage Criterion, gets A=0.05.
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