CN104682434A - Graph-theory analysis method for common-mode current paths of photovoltaic grid-connected inverters - Google Patents

Graph-theory analysis method for common-mode current paths of photovoltaic grid-connected inverters Download PDF

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CN104682434A
CN104682434A CN201510105211.6A CN201510105211A CN104682434A CN 104682434 A CN104682434 A CN 104682434A CN 201510105211 A CN201510105211 A CN 201510105211A CN 104682434 A CN104682434 A CN 104682434A
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current path
node
common mode
mode current
photovoltaic
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CN104682434B (en
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戴志威
舒杰
张伟
吴昌宏
宋香荣
吴志锋
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Guangzhou Institute of Energy Conversion of CAS
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    • H02J3/383—
    • 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
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
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    • 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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Abstract

The invention discloses a kind of Graph Analysis method of photovoltaic combining inverter common mode current path,Itself the following steps are included: step 1,Photovoltaic combining inverter network node figure is drawn according to photovoltaic combining inverter common mode current topological circuit,Photovoltaic combining inverter network node figure is the node binary connection relationship being made of node and directed edge; Step 2,The matrix model A of n × n is established according to node binary connection relationship; Step 3,It calculates and obtains current path function δ; Step 4,Illegal access in current path function δ is rejected,It obtains rejecting the current path function δ ' after redundant via; Step 5,According to the current path function δ ' acquisition common mode current path function after rejecting redundant via Step 6 passes through common mode current path function Judge the switch state of each common mode current path. The present invention helps to instruct the common mode current of photovoltaic combining inverter to inhibit, derivative new topological structure.

Description

The Graph Analysis method of photovoltaic combining inverter common mode current path
Technical field
The present invention relates to the analysis of converters topological structure, propose a kind of Graph Analysis method of photovoltaic combining inverter common mode current path, belong to Technics of Power Electronic Conversion technology and solar energy generation technology field.
Background technology
Converters is widely used in industrial automation and power converter occasion, from two level converters being applicable to low middle pressure, to the three level even multi-level converter being applicable to mesohigh, topological structure is day by day complicated, switching tube and energy-storage travelling wave tube number are on the increase, the operation mode of circuit topology is also in continuous increase, and this brings huge resistance with regard to giving the research & design of power electronics topology.Graph theory (Graph Theory) is a kind of mathematical tool studying figure, as long as the system containing binary crelation can be analyzed by graph theory.Current graph theory has been widely used in the multinode fields such as the Internet, electric power system, digital communication, economic management, social organization's model, is subject to the attention of whole world mathematical region and scientific circles.
Photovoltaic combining inverter can be divided into single-phase photovoltaic grid-connected inverter and three-phase photovoltaic grid-connected inverting device by output characteristic, has isolating transformer photovoltaic combining inverter and without isolating transformer photovoltaic combining inverter according to being divided into or without isolating transformer.In order to reduce costs, weight reduction, reduced volume, raise the efficiency, be used widely without isolating transformer photovoltaic combining inverter.But there is common mode current over the ground without isolating transformer photovoltaic combining inverter, is a problem demanding prompt solution.The size of common mode current depends primarily on frequency and the amplitude of voltage fluctuation in parasitic capacitance, also relevant with the size of feedthrough capacitor.The generation of common mode current is not only relevant with inverter topology, also relevant with the control strategy of switching tube.So, study without the common mode current path in isolating transformer photovoltaic combining inverter operation mode most important to suppression common mode current.
T-shaped three-level photovoltaic grid-connected inverter has merged the advantage of two level and three-level inverter, existing two-level inverter conduction loss is little, the advantage that number of elements is few, there is again three-level inverter good output waveform, the advantage that efficiency is high is very promising a kind of three-level inverter topology structure.Traditional converters common mode current suppressing method is many by inspiration and trial, does not have a kind of theoretical analysis method as guidance.The present invention as case study on implementation, details the Graph Analysis method of photovoltaic combining inverter common mode current path using T-shaped three-level photovoltaic grid-connected inverter.
Summary of the invention
The present invention proposes a kind of photovoltaic combining inverter common mode current path analytical method.This invention has universality, and can analyze the converters topology of multinode, convenient guidance suppresses common mode current.
The technical scheme that technical solution problem of the present invention adopts is:
The Graph Analysis method of photovoltaic combining inverter common mode current path, it comprises the following steps:
Step 1, draw photovoltaic combining inverter network node figure according to photovoltaic combining inverter common mode current topological circuit, described photovoltaic combining inverter network node figure is the node binary annexation be made up of node and directed edge; Wherein, node is each element junction in topological circuit, is numbered by the order of 1 to n, n be greater than 1 positive integer; Whether described node binary annexation is have element to be directly connected between each node, and whether the element be directly connected exists current path, if there is element to be directly connected, connected by directed edge between the node that then this element is corresponding, described directed edge is the component symbol connected between node, if the element be directly connected exists current path, then on directed edge, indicate direction of current flow arrow;
Step 2, set up the matrix model A of n × n according to node binary annexation, the element a in described matrix model A ijwith node binary annexation one_to_one corresponding, and meet:
Wherein, i, j are node ID, respectively the row, column sequence number of homography model A, 1≤i≤n, 1≤j≤n;
Step 3, calculating current path function δ, described current path function δ are the determinant of matrix model A the expression formula of the multinomial sum after middle removal quadratic term;
Step 4, the illegal path in described current path function δ to be rejected, obtain the current path function δ ' after eliminate redundancy path;
Step 5, according to the current path function δ ' acquisition common mode current path function after described eliminate redundancy path described common mode current path function multinomial sum corresponding to common mode current path, described common mode current path flows through feedthrough capacitor C simultaneously pVwith the current path exchanging earth impedance Z, in the current path function δ ' after the multinomial corresponding to described common mode current path is eliminate redundancy path, comprise feedthrough capacitor C simultaneously pVwith the multinomial exchanging earth impedance Z;
Step 6, by common mode current path function judge the on off state of each common mode current path.
Described photovoltaic combining inverter is T-shaped three-level photovoltaic grid-connected inverter.
In the common mode current topological circuit of described T-shaped three-level photovoltaic grid-connected inverter, parasitic parameter C pV1and C pV2for photovoltaic module is to the feedthrough capacitor of the earth; U pVfor photovoltaic module output voltage; C 1and C 2it is equivalent derided capacitors; C a, C b, C cbe respectively the parasitic capacitance between three-phase bridge road output and the earth; S a1, S a2, S a3, S a4, S b1, S b2, S b3, S b4, S c1, S c2, S c3, S c4it is the brachium pontis switching tube of 12 band fly-wheel diodes; L a, L b, L c, C fa, C fb, C fc, L fa, L fb, L fcbe respectively inverter LCL filter parameter; e a, e b, e cfor three-phase phase voltage; Z is three-phase mid point earth impedance.
In the network node figure of described T-shaped three-level photovoltaic grid-connected inverter, total node 11, i.e. n=11, wherein, node 1 is photovoltaic module positive pole; Node 2 is A bridge road output; Node 3 is B bridge road output; Node 4 is C bridge road output; Node 5 is A bridge road clamper branch node; Node 6 is B bridge road clamper branch node; Node 7 is C bridge road clamper branch node; Node 8 is three-phase electricity mid point; Node 9 is photovoltaic module negative pole; Node 10 is derided capacitors mid point; Node 11 is the earth.
The matrix model A of described T-shaped three-level photovoltaic grid-connected inverter is:
A = 1 S a 1 S b 1 S c 1 0 0 0 0 0 C 1 0 S a 1 1 0 0 S a 3 0 0 e a S a 4 0 C a S b 1 0 1 0 0 S b 3 0 e b S b 4 0 C b S c 1 0 0 1 0 0 S c 3 e c S c 4 0 C c 0 S a 3 0 0 1 0 0 0 0 S a 2 0 0 0 S b 3 0 0 1 0 0 0 S b 2 0 0 0 0 S c 3 0 0 1 0 0 S c 2 0 0 e a e b e c 0 0 0 1 0 0 Z U PV S a 4 S b 4 S c 4 0 0 0 0 1 C 2 C PV C 1 0 0 0 S a 2 S b 2 S c 2 0 C 2 1 0 0 C a C b C c 0 0 0 Z C PV 0 1 .
The current path function rejecting of described T-shaped three-level photovoltaic grid-connected inverter does not meet switch modulation rule and follows following rule: S k1and S k3state is complementary; S k2and S k4state is complementary; S k1and S k4forbid conducting simultaneously; Wherein, k gets a, b, c, and described state complementation is one and is in conducting state, and another is then in cut-off state.
The common mode current path function of described T-shaped three-level photovoltaic grid-connected inverter for:
δ C pv = 2 C 2 S a 2 S a 3 e a ZC PV + 2 C 2 S b 2 S b 3 e b ZC PV + 2 C 2 S c 2 S c 3 e c ZC PV + 2 C 2 C 1 S a 1 e a ZC PV + 2 C 2 C 1 S b 1 e b ZC PV + 2 C 2 C 1 S c 1 e c ZC PV + 2 S a 4 e a ZC PV + 2 S b 4 e b ZC PV + 2 S c 4 e c ZC PV + U PV S a 1 e a ZC PV + U PV S b 1 e b ZC PV + U PV S c 1 e c ZC PV + U PV C 1 S a 2 S a 3 e a ZC PV + U PV C 1 S b 2 S b 3 e b ZC PV + U PV C 1 S c 2 S c 3 e c ZC PV
Wherein, the coefficient 2 in multinomial represents the current reversibility of the common mode current path corresponding to this multinomial.
The on off state that the common mode current path of described T-shaped three-level photovoltaic grid-connected inverter is corresponding is as shown in the table:
In this table, when only comprising S in the multinomial that common mode current path is corresponding k1, then this S k1corresponding bridge road output end voltage is just, is labeled as P; When only comprising S in the multinomial that common mode current path is corresponding k2and S k3, then this S k2and S k3corresponding bridge road output end voltage is zero, is labeled as O; When only comprising S in the multinomial that common mode current path is corresponding k4, then this S k4corresponding bridge road output end voltage is negative, is labeled as N; Common mode current path 2C 2s a2s a3e azC pVon off state O** represents A bridge road, the output end voltage on B bridge road and C bridge road is respectively O, *, *, wherein to represent output end voltage indefinite for *, desirable P, O, N.
After have found common mode path and on off state thereof, according to the direction of common mode passage current, offsetting existing path with reverse path can suppress common mode current.Illustrate for 1,4,7,10,13 states on A bridge road:
1 state and 13 states are same state (being O**), and wherein 1 state two path direction is contrary, cancels out each other, only surplus 13 state path; 4 states and 10 states are same state (being P**), and C 1c 2with U pvhomology, therefore can be equivalent to 4 states, and 4 state two path directions are contrary, cancel out each other; 7 state two path directions are contrary, cancel out each other.Final A bridge road common mode current path number reduces (being namely only left 13 states), thus effectively inhibits common mode current.
Compared with prior art, Advantages found of the present invention exists:
1, existing photovoltaic combining inverter common mode current suppressing method, comprises hardware modifications and control method is improved, and mostly relies on inspiration and experiment to attempt, lacks ripe mathematical theory and instruct.Especially complicated topological structure, also not for the research of common mode current path.The present invention solves this problem well;
2, programming realization is convenient in this invention, is applicable to numerical calculation, substantially reduces the cycle of converters topology research & design.
3, this invention is also graph theory in a successful Application of Technics of Power Electronic Conversion field and field of solar thermal power generation, and its conclusion can instruct photovoltaic combining inverter common mode current to suppress, and derives how new topological structure.
Accompanying drawing explanation
Fig. 1 is the Graph Analysis method operational flowchart of photovoltaic combining inverter common mode current path;
Fig. 2 is T-shaped three-level photovoltaic grid-connected inverter common mode current topological circuit figure;
Fig. 3 is T-shaped three-level photovoltaic grid-connected inverter node topology figure;
Fig. 4 is T-shaped three-level photovoltaic grid-connected inverter network node figure.
Embodiment
Below in conjunction with the drawings and specific embodiments, content of the present invention is described in further details.
Embodiment:
Fig. 1 is the operational flowchart of the photovoltaic combining inverter common mode current path Graph Analysis method that the present invention proposes.This analytical method is implemented by following six steps:
Step 1, drafting photovoltaic combining inverter common mode current topological circuit, arrive the serial number of n by 1 to element junction;
Step 2, drafting photovoltaic combining inverter network node figure.Node is 1 to n, and directed edge is component symbol; Set up node binary crelation according to element characteristic, electric current the limit of one-way flow can only be pressed flow direction and indicates unidirectional arrow, and electric current the limit of two-way flow can indicate four-headed arrow;
Step 3, set up n × n matrix model according to binary annexation.Directly be connected with or without element according between photovoltaic combining inverter network node figure interior joint, and whether the element be directly connected exists current path, set up the matrix model A of photovoltaic combining inverter common mode topology, entry of a matrix element a ij(i, j are respectively node ID, the row, column sequence number of homography) and node binary crelation one_to_one corresponding, meet:
Step 4, current path function calculate.δ is defined as current path function, asks the determinant of matrix model A the oriented current circuit of current path function for likely occurring in theory.Because an actual current loop through a node twice, therefore can not be omitted in quadratic term, the expression formula of final multinomial sum is current path function δ.
Step 5, redundant via are rejected.The factor in path function is all directed quantity, note rejecting following two kinds of illegal paths.The first, by the path of power supply direct short-circuit; The second, do not meet the path of switch modulation rule.
Step 6, common mode current path analysis.Current path function δ ' after eliminate redundancy path contains all current paths of photovoltaic combining inverter common mode current model.According to the definition of common mode current, comprise feedthrough capacitor C pVnamely there is common mode current to flow through with the path exchanging earth impedance Z, from δ ', extract common mode current path and common mode current path function
Case study on implementation below in conjunction with T-shaped three-level photovoltaic grid-connected inverter is described application of the present invention.
Step 1, draws T-shaped three-level photovoltaic grid-connected inverter common mode current topological circuit figure.
As shown in Figure 2.This be one without isolating transformer photovoltaic combining inverter structure, so need study common mode current problem over the ground.In Fig. 2, parasitic parameter C pV1and C pV2for photovoltaic module is to the feedthrough capacitor of the earth, depend on the factors such as photovoltaic module area, soil property, air humidity, mounting means; U pVfor photovoltaic module output voltage; C 1and C 2it is equivalent derided capacitors; C a, C b, C cfor the parasitic capacitance between three-phase bridge road output and the earth; S a1, S a2, S a3, S a4, S b1, S b2, S b3, S b4, S c1, S c2, S c3, S c4it is the brachium pontis switching tube of 12 band fly-wheel diodes; L a, L b, L c, C fa, C fb, C fc, L fa, L fb, L fcbe respectively inverter LCL filter parameter; e a, e b, e cfor three-phase phase voltage; Z is three-phase mid point earth impedance.
Step 2, draws T-shaped three-level photovoltaic grid-connected inverter network node figure.
First the T-shaped three-level photovoltaic grid-connected inverter node topology figure of Fig. 3 is drawn.For the common mode current of high frequency, photovoltaic cell is equivalent to lead directly to, parasitic capacitance C pV1and C pV2for parallel relationship, be equivalent to C pV,
C PV＝C PV1+C PV2＝2C PV1＝2C PV2
The effect of LCL filter is the high order harmonic component in filtering output voltage and grid-connected current, and and be not directly electrically connected between the earth, when node topology is analyzed, cast out, to reduce minimizing node number.
Topological structure after simplification has node 11, and from 1 to 11 numberings, corresponding relation is as figure: node 1 is photovoltaic module positive pole; Node 2 is A bridge road output; Node 3 is B bridge road output; Node 4 is C bridge road output; Node 5 is A bridge road clamper branch node; Node 6 is B bridge road clamper branch node; Node 7 is C bridge road clamper branch node; Node 8 is three-phase electricity mid point; Node 9 is photovoltaic module negative pole; Node 10 is derided capacitors mid point; Node 11 is the earth.
T-shaped three-level photovoltaic grid-connected inverter node topology figure according to Fig. 3, draws T-shaped three-level photovoltaic grid-connected inverter network node figure, as shown in Figure 4.T-shaped three-level photovoltaic grid-connected inverter is primarily of element compositions such as power supply, inductance, electric capacity, resistance, switches, do not consider the impact of control model on network node figure, be two ends model by element equivalent, thus the common mode current prototype network node diagram of T-shaped three-level photovoltaic grid-connected inverter can be set up.The direction of current flowing is determined by the characteristic of element: to the element such as switch, AC power of inductance, electric capacity, passive resistance, band fly-wheel diode, and electric current can two-way flow, with four-headed arrow line connected node; Without elements such as fly-wheel diode switch, diode, DC power supply, electric current can only one-way flow, with unidirectional arrow line connected node.
Step 3, sets up 11 × 11 matrix models according to binary annexation.
According between node with or without electrical connection, have the element of electrical connection with or without current path, set up the matrix model A of 11 × 11, its element a ij(i, j are respectively node ID, the row, column sequence number of homography) meets:
T-shaped three-level photovoltaic grid-connected inverter network node figure according to Fig. 4, and the definition of matrix model, the matrix model of T-shaped three-level photovoltaic grid-connected inverter common mode current topology is:
A = 1 S a 1 S b 1 S c 1 0 0 0 0 0 C 1 0 S a 1 1 0 0 S a 3 0 0 e a S a 4 0 C a S b 1 0 1 0 0 S b 3 0 e b S b 4 0 C b S c 1 0 0 1 0 0 S c 3 e c S c 4 0 C c 0 S a 3 0 0 1 0 0 0 0 S a 2 0 0 0 S b 3 0 0 1 0 0 0 S b 2 0 0 0 0 S c 3 0 0 1 0 0 S c 2 0 0 e a e b e c 0 0 0 1 0 0 Z U PV S a 4 S b 4 S c 4 0 0 0 0 1 C 2 C PV C 1 0 0 0 S a 2 S b 2 S c 2 0 C 2 1 0 0 C a C b C c 0 0 0 Z C PV 0 1
Wherein, all symbols refer to directed edge, and non parameter tolerance.
Step 4, current path function calculates.
Ask the determinant of T-shaped three-level photovoltaic grid-connected inverter common mode current matrix model A wherein contain a large amount of square factor items.The oriented current circuit of current path function for likely occurring in theory.Because an actual current loop through a node twice, therefore can not be omitted in quadratic term, the expression formula of final multinomial sum is the current path function δ of T-shaped three-level photovoltaic grid-connected inverter common mode current circuit: be have the multinomial of 4982, wherein quadratic term 4044, therefore δ have the multinomial of 938.
Step 5, redundant via is rejected.
The factor in current path function is all directed quantity, note rejecting following two kinds of illegal paths.The first, by power supply U pVthe path of direct short-circuit; The second, do not meet the path of switch modulation rule.During switch modulation, (k gets a, b, c): S to follow following rule k1and S k3state is complementary; S k2and S k4state is complementary; S k1and S k4forbid conducting simultaneously.After eliminate redundancy path, current path function δ ' is: δ ' has the multinomial of 398.
Step 6, common mode current path Functional Analysis.
Current path function δ ' after eliminate redundancy path contains all current paths of T-shaped three-level photovoltaic grid-connected inverter common mode current model.According to the definition i of common mode current cm,
i cm = C PV dU Cpv dt
And common mode current model, comprise feedthrough capacitor C pVnamely there is common mode current to flow through with the path exchanging earth impedance Z, from δ ', extract common mode current path, totally 15, common mode current path function for:
δ C pv = 2 C 2 S a 2 S a 3 e a ZC PV + 2 C 2 S b 2 S b 3 e b ZC PV + 2 C 2 S c 2 S c 3 e c ZC PV + 2 C 2 C 1 S a 1 e a ZC PV + 2 C 2 C 1 S b 1 e b ZC PV + 2 C 2 C 1 S c 1 e c ZC PV + 2 S a 4 e a ZC PV + 2 S b 4 e b ZC PV + 2 S c 4 e c ZC PV + U PV S a 1 e a ZC PV + U PV S b 1 e b ZC PV + U PV S c 1 e c ZC PV + U PV C 1 S a 2 S a 3 e a ZC PV + U PV C 1 S b 2 S b 3 e b ZC PV + U PV C 1 S c 2 S c 3 e c ZC PV
U cpvfor parasitic capacitance C pVthe voltage at two ends, number " 2 " represents this passage current can two-way flow;
List corresponding on off state, as shown in table 1.As conducting S k1, be P; Work as S k2and S k3conducting is simultaneously O; Work as S k4conducting is N; Wherein " * " represents indeterminate state, desirable P, O, N state.
Table 1 T-shaped three-level photovoltaic grid-connected inverter common mode current path table
In the implementation case, the symbol in model matrix and current path function refers to directed edge, and non parameter tolerance.
Above-listed detailed description is illustrating for possible embodiments of the present invention, and this embodiment is also not used to limit the scope of the claims of the present invention, and the equivalence that all the present invention of disengaging do is implemented or changed, and all should be contained in the scope of the claims of this case.

Claims (8)

1. the Graph Analysis method of photovoltaic combining inverter common mode current path, it is characterized in that, it comprises the following steps:
Step 1, draw photovoltaic combining inverter network node figure according to photovoltaic combining inverter common mode current topological circuit, described photovoltaic combining inverter network node figure is the node binary annexation be made up of node and directed edge; Wherein, node is each element junction in topological circuit, is numbered by the order of 1 to n, n be greater than 1 positive integer; Whether described node binary annexation is have element to be directly connected between each node, and whether the element be directly connected exists current path, if there is element to be directly connected, connected by directed edge between the node that then this element is corresponding, described directed edge is the component symbol connected between node, if the element be directly connected exists current path, then on directed edge, indicate direction of current flow arrow;
Step 2, set up the matrix model A of n × n according to node binary annexation, the element a in described matrix model A ijwith node binary annexation one_to_one corresponding, and meet:
Wherein, i, j are node ID, respectively the row, column sequence number of homography model A, 1≤i≤n, 1≤j≤n;
Step 3, calculating obtain current path function δ, and described current path function δ is the determinant of matrix model A the expression formula of the multinomial sum after middle removal quadratic term;
Step 4, the illegal path in described current path function δ to be rejected, obtain the current path function δ ' after eliminate redundancy path;
Step 5, according to the current path function δ ' acquisition common mode current path function after described eliminate redundancy path described common mode current path function multinomial sum corresponding to common mode current path, described common mode current path flows through feedthrough capacitor C simultaneously pVwith the current path exchanging earth impedance Z, in the current path function δ ' after the multinomial corresponding to described common mode current path is eliminate redundancy path, comprise feedthrough capacitor C simultaneously pVwith the multinomial exchanging earth impedance Z;
Step 6, by common mode current path function judge the on off state of each common mode current path.
2. the Graph Analysis method of photovoltaic combining inverter common mode current path according to claim 1, is characterized in that, described photovoltaic combining inverter is T-shaped three-level photovoltaic grid-connected inverter.
3. the Graph Analysis method of photovoltaic combining inverter common mode current path according to claim 2, is characterized in that, in the common mode current topological circuit of described T-shaped three-level photovoltaic grid-connected inverter, and parasitic parameter C pV1and C pV2for photovoltaic module is to the feedthrough capacitor of the earth; U pVfor photovoltaic module output voltage; C 1and C 2it is equivalent derided capacitors; C a, C b, C cbe respectively the parasitic capacitance between three-phase bridge road output and the earth; S a1, S a2, S a3, S a4, S b1, S b2, S b3, S b4, S c1, S c2, S c3, S c4it is the brachium pontis switching tube of 12 band fly-wheel diodes; L a, L b, L c, C fa, C fb, C fc, L fa, L fb, L fcbe respectively inverter LCL filter parameter; e a, e b, e cfor three-phase phase voltage; Z is three-phase mid point earth impedance.
4. the Graph Analysis method of photovoltaic combining inverter common mode current path according to claim 3, is characterized in that, in the network node figure of described T-shaped three-level photovoltaic grid-connected inverter, total node 11, i.e. n=11, wherein, node 1 is photovoltaic module positive pole; Node 2 is A bridge road output; Node 3 is B bridge road output; Node 4 is C bridge road output; Node 5 is A bridge road clamper branch node; Node 6 is B bridge road clamper branch node; Node 7 is C bridge road clamper branch node; Node 8 is three-phase electricity mid point; Node 9 is photovoltaic module negative pole; Node 10 is derided capacitors mid point; Node 11 is the earth.
5. the Graph Analysis method of photovoltaic combining inverter common mode current path according to claim 4, is characterized in that, the matrix model A of described T-shaped three-level photovoltaic grid-connected inverter is:
A = 1 S a 1 S b 1 S c 1 0 0 0 0 0 C 1 0 S a 1 1 0 0 S a 3 0 0 e a S a 4 0 C a S b 1 0 1 0 0 S b 3 0 e b S b 4 0 C b S c 1 0 0 1 0 0 S c 3 e x S c 4 0 C c 0 S a 3 0 0 1 0 0 0 0 S a 2 0 0 0 S b 3 0 0 1 0 0 0 S b 2 0 0 0 0 S c 3 0 0 1 0 0 S c 2 0 0 e a e b e c 0 0 0 1 0 0 Z U PV S a 4 S b 4 S c 4 0 0 0 0 1 C 2 C PV C 1 0 0 0 S a 2 S b 2 S c 2 0 C 2 1 0 0 C a C b C c 0 0 0 Z C PV 0 1 .
6. the Graph Analysis method of photovoltaic combining inverter common mode current path according to claim 5, is characterized in that, the current path function rejecting of described T-shaped three-level photovoltaic grid-connected inverter does not meet switch modulation rule and follows following rule: S k1and S k3state is complementary; S k2and S k4state is complementary; S k1and S k4forbid conducting simultaneously; Wherein, k gets a, b, c, and described state complementation is one and is in conducting state, and another is then in cut-off state.
7. the Graph Analysis method of photovoltaic combining inverter common mode current path according to claim 6, is characterized in that, the common mode current path function of described T-shaped three-level photovoltaic grid-connected inverter for:
δ C pv = 2 C 2 S a 2 S a 3 e a Z C PV + 2 C 2 S b 2 S b 3 e b Z C PV + 2 C 2 S c 2 S c 3 e c ZC PV + 2 C 2 C 1 S a 1 e a ZC PV + 2 C 2 C 1 S b 1 e b ZC PV + 2 C 2 C 1 S c 1 e c ZC PV + 2 S a 4 e a AC PV + 2 S b 4 e b ZC PV + 2 S c 4 e c ZC PV + U PV S a 1 e a ZC PV + U PV S b 1 e b ZC PV + U PV S c 1 e c ZC PV + U PV C 1 S a 2 S a 3 e a ZC PV + U PV C 1 S b 2 S b 3 e b ZC PV + U PV C 1 S c 2 S c 3 e c ZC PV
Wherein, the coefficient 2 in multinomial represents the electric current of the common mode current path corresponding to this multinomial can two-way flow.
8. the Graph Analysis method of photovoltaic combining inverter common mode current path according to claim 7, is characterized in that, the on off state that the common mode current path of described T-shaped three-level photovoltaic grid-connected inverter is corresponding is as shown in the table:
In this table, when only comprising S in the multinomial that common mode current path is corresponding k1, then this S k1corresponding bridge road output end voltage is just, is labeled as P; When only comprising S in the multinomial that common mode current path is corresponding k2and S k3, then this S k2and S k3corresponding bridge road output end voltage is zero, is labeled as O; When only comprising S in the multinomial that common mode current path is corresponding k4, then this S k4corresponding bridge road output end voltage is negative, is labeled as N; Common mode current path 2C 2s a2s a3e azC pVon off state O** represents A bridge road, the output end voltage on B bridge road and C bridge road is respectively O, *, *, wherein to represent output end voltage indefinite for *, any one in desirable P, O, N.
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JP2010207056A (en) * 2009-03-06 2010-09-16 Meidensha Corp Power interchange processing method of power distribution system

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010207056A (en) * 2009-03-06 2010-09-16 Meidensha Corp Power interchange processing method of power distribution system

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丘东元等: "电力电子变换器结构性故障的有向图论诊断方法", 《电机与控制学报》 *

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