CN112966463B - Efficient simulation method for distributed grid-connected system of converter group - Google Patents
Efficient simulation method for distributed grid-connected system of converter group Download PDFInfo
- Publication number
- CN112966463B CN112966463B CN202110234479.5A CN202110234479A CN112966463B CN 112966463 B CN112966463 B CN 112966463B CN 202110234479 A CN202110234479 A CN 202110234479A CN 112966463 B CN112966463 B CN 112966463B
- Authority
- CN
- China
- Prior art keywords
- converter
- equivalent
- switch
- simulation
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000004088 simulation Methods 0.000 title claims abstract description 76
- 238000000034 method Methods 0.000 title claims abstract description 41
- 239000003990 capacitor Substances 0.000 claims description 42
- 239000011159 matrix material Substances 0.000 claims description 22
- 238000004364 calculation method Methods 0.000 claims description 6
- 238000005516 engineering process Methods 0.000 abstract description 5
- 230000001052 transient effect Effects 0.000 abstract description 5
- 230000008569 process Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 3
- 238000004422 calculation algorithm Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005094 computer simulation Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/30—Circuit design
- G06F30/36—Circuit design at the analogue level
- G06F30/367—Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/16—Matrix or vector computation, e.g. matrix-matrix or matrix-vector multiplication, matrix factorization
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2113/00—Details relating to the application field
- G06F2113/04—Power grid distribution networks
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Theoretical Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Mathematical Analysis (AREA)
- General Engineering & Computer Science (AREA)
- Pure & Applied Mathematics (AREA)
- Computational Mathematics (AREA)
- Data Mining & Analysis (AREA)
- Mathematical Optimization (AREA)
- Software Systems (AREA)
- Databases & Information Systems (AREA)
- Computing Systems (AREA)
- Algebra (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Evolutionary Computation (AREA)
- Geometry (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses a high-efficiency simulation method of a distributed grid-connected system of a converter group, which comprises the steps of firstly establishing an equivalent circuit model of an original circuit model of a single converter, then establishing a distributed grid-connected simulation system model of the converter group comprising a plurality of Norton equivalent circuits, and adopting a comprehensive converter switch and supporting capacitance equivalent modeling technology and a distributed grid-connected system of the converter group of the Norton equivalent technology. The modeling method is simple, strong in universality, high in simulation efficiency and precision, and the high-efficiency simulation method of the large-scale converter group distributed grid-connected system capable of simulating the internal electrical transient characteristics of the converter.
Description
Technical Field
The invention relates to the technical field of power electronic simulation modeling, in particular to a high-efficiency simulation method of a distributed grid-connected system of a converter group.
Background
Along with the development of power electronics technology and the increase of application demands, the scale of a grid-connected system of a converter group is larger and larger, such as a vehicle grid system, a wind power plant, a photovoltaic power station and the like. Because of the numerous converters, the interaction mechanisms between the converters and the power grid are complex, the optimal matching of the converter device and the power grid and the coordination control difficulty of the converter group are large, and once accidents occur, the numerous equipment is damaged, the economic loss is huge, the repair cost is high and the time period is long. Therefore, the safe, stable and reliable operation of the large-scale converter group distributed grid-connected system is particularly important.
The inventor provides a high-efficiency simulation method for concentrated grid connection of multiple converters in the high-efficiency simulation method of a concentrated grid connection system of the multiple converters, but the method is not suitable for distributed grid connection of the converter groups:
(1) The grid connection positions of all the converters of the multi-converter centralized grid connection system are the same point, so that the switch equivalent admittances of all the converters are consistent, G s is adopted, and the node admittance matrixes of all the converters are consistent; when the current transformer groups are in distributed grid connection, different grid connection positions of the current transformers have influence on the admittances of the switches Guan Dengxiao, namely the switch equivalent admittances of the current transformers at different positions are different, so that the node admittance matrixes of the current transformers are inconsistent.
(2) The high-efficiency simulation method of the multi-converter centralized grid-connected system simplifies and combines a plurality of converters into a model with 2 nodes and 2 branches; the original ultra-large-scale admittance matrix is reduced to 2 low-order matrices (admittance matrix of equivalent circuit of the multi-converter centralized grid-connected system and node admittance matrix unified by all converters), and the two low-order constant matrices with fixed orders are only needed to be generated and inverted at the initial stage of simulation; when the current transformer groups are in distributed grid connection, each current transformer is simplified into a model with 2 nodes and 2 branches, but the models cannot be combined because the positions are not the same points, so that the original super-large-scale admittance matrix is reduced to a plurality of low-order matrixes, and a plurality of low-order constant matrixes with fixed orders are required to be generated and inverted at the initial stage of simulation.
(3) According to the efficient simulation method of the multi-converter centralized grid-connected system, the switch and the supporting capacitor of the converter are equivalent to the current source parallel admittance according to the trapezoidal integration method, however, the trapezoidal method has the following defects: (a) The switching state of the converter may cause numerical oscillation; (b) The equivalent current source of the converter is related to the current flowing through the switch and the voltages at two ends of the switch; (c) The current flowing through the converter switch or the capacitor needs to be calculated, and the calculation amount is large.
In view of the defects, the invention provides the high-efficiency simulation method for the large-scale converter group distributed grid-connected system, which has the advantages of simple modeling method, strong universality, high simulation efficiency and precision and capability of simulating the internal electrical transient characteristics of the converter.
Disclosure of Invention
The invention aims to provide a high-efficiency simulation method of a converter group distributed grid-connected system, which is suitable for any power electronic switch converter group (IGBT, thyristor, diode, ideal switch and the like) distributed grid-connected system.
In order to achieve the above purpose, the technical scheme of the invention is a high-efficiency simulation method of a distributed grid-connected system of a converter group, comprising the following steps:
Step 1, before simulation starts, setting parameters of a simulation step delta t, a simulation total duration t f, a converter and a converter group distributed grid-connected system;
step 2, calculating equivalent admittance of the converter switch and the supporting capacitor: according to the position of the current transformer connected with the power grid, an original model of a single current transformer is established, each current transformer is simplified into an equivalent model of 2 nodes and 2 branches, the switch equivalent admittance of each current transformer is determined through simulation comparison and debugging, the switch equivalent admittance is marked as G s1、Gs2、Gsk......Gsx, x is the number of the current transformers, and k is any one of the current transformers;
firstly, establishing an equivalent circuit model of a single converter original circuit model, and then establishing a converter group distributed grid-connected simulation system model comprising a plurality of Norton equivalent circuits, wherein the equivalent circuit model comprises the following specific steps of: based on the backward Euler method and the on/off characteristics of the power electronic switch, a branch of the current source parallel admittance is deduced and adopted to simulate the power electronic switch (diode, IGBT, thyristor, ideal switch and the like), supporting capacitor and the like in the converter, and when the switch is conducted, the power electronic switch is calculated by the following relational expression:
ik1(t)＝imn(t-Δt) (1)
when the switch is off, it is calculated by the following relation:
ik1(t)＝-Gsk×Vmn(t-Δt) (2)
Wherein G sk is a constant greater than 0 and less than 1, and i mn is a current flowing through a kth converter switching tube in the m and n end points; i k1、Vmn is a current source connected to the m and n terminals and the voltages at two ends of the current source; t is simulation time; Δt is the simulation time step.
For the support capacitance, it is calculated by the following relation:
Wherein i kc、Gsc is the equivalent current source and admittance of the supporting capacitor of the kth converter respectively; c is the value of the supporting capacitor; v mo is the voltage between the m and o terminals.
Step 3, constructing an admittance matrix of each converter node shown in the formula (4); according to the Norton theorem, calculating to obtain the equivalent admittance G 1、G2......GX of the Norton equivalent circuit of each converter;
Wherein V m、Vn、Vp is the voltage of the node m, n and p to the reference node respectively; and similarly, node admittance network equations of other converters can be obtained.
Step4, establishing a node admittance matrix of an equivalent circuit of the converter group distributed grid-connected system;
Step 5, initializing the switch state of each converter and flowing the switch current and the voltage at two ends of the switch at the moment t-delta t when the initial simulation moment is t; initializing the voltages at two ends of the supporting capacitor of each converter at the moment of t-delta t;
Step 6, calculating the equivalent current of each switch of each converter at the time t through formulas (1) - (2) according to each switch state of each converter and the equivalent admittance of the converter switch and the supporting capacitor calculated in step 2; calculating equivalent current i 1、i2......ix of each converter supporting capacitor at the time t by the formula (3);
step 7, calculating to obtain an equivalent current source of the Norton equivalent circuit of each converter according to the Norton theorem;
Step 8, solving a node admittance network equation of the equivalent circuit of the distributed grid-connected system of the converter group according to the system node admittance matrix obtained in the step 4 and the equivalent current sources of the Norton equivalent circuits of the converters obtained in the step 7, and calculating to obtain the network side voltage V s1、VS2......VSX of each converter;
Step 9, substituting the calculated network side voltage V s1、VS2......VSX of each converter into the admittance network equation of each converter node established in the step 3, and solving to obtain the current flowing through each switch of each converter at the moment t, the voltages at two ends of the switch and the voltages at two ends of the supporting capacitor by adopting the formula (4);
Step 10, i' =t+Δt, and judge whether the emulation duration exceeds the total emulation duration t f of settlement, if not exceed, by the switch control of every converter, and combine the power electronic switching characteristic, confirm every converter on-off state, and go to step 6; if t f is exceeded, the simulation ends.
The beneficial effects are that:
(1) The high-efficiency simulation method of the distributed grid-connected system of the converter group is provided, wherein the high-efficiency simulation method comprises the steps of integrating a converter switch, a supporting capacitor equivalent modeling technology and a converter Norton equivalent technology.
(2) According to the invention, each converter is equivalent to a branch of a historical current source and admittance in parallel connection, then an electromagnetic transient solving process of a simulation step length is carried out in parallel with a power grid, and then various electric quantities of a switch and a supporting capacitor in each converter at each simulation moment are calculated according to the obtained power grid voltage of each converter and a node admittance network equation of each converter.
(3) The method has the advantages that the converter switches and the supporting capacitors are equivalent to current source parallel admittances, the admittance value is unchanged when the switch state is changed, and the value of the current source is changed, so that the Norton equivalent resistance of each converter is a fixed constant, and therefore, the node admittance matrix of the converter group and the power grid, the admittance matrix of each converter are generated and inverted once only in initial simulation time, namely, the node admittance matrix of the converter group grid-connected system and the node admittance matrix of each converter do not need to be regenerated and inverted in each subsequent simulation step, and the node admittance matrix of the converter group grid-connected system, the node admittance matrix of each converter and the inversion time respectively can be greatly saved in the simulation process.
(4) The converters are equivalent to current source parallel admittance, so that each converter model of multiple nodes and multiple branches is simplified into a simplified model of 2 nodes and 2 branches, and the operation amount is greatly reduced.
(5) The converters are equivalent to current source parallel admittance, so that natural decoupling between a power grid, a converter group and the converters is realized, the converters can be detached from any strong coupling position, virtual resistor auxiliary decoupling is not needed, the decoupling position is flexible, and the problem of numerical oscillation or precision reduction caused by adding virtual resistors is avoided.
(6) The invention reduces the original super-large-scale admittance matrix into a plurality of low-order matrixes, and only needs to invert the low-order constant matrixes with a plurality of fixed orders simultaneously in the simulation process, thereby avoiding directly inverting the high-order matrixes and obviously reducing the calculation time.
(7) Based on the backward Euler method, the switch and the supporting capacitor of the converter are equivalent to the current source parallel admittance, and compared with the trapezoidal method, the parallel admittance has the advantages that: (a) The backward Euler method can effectively avoid numerical oscillation caused by switching of the state of a converter switch; (b) The equivalent current source of the converter is only related to the current flowing through the switch or the voltage across the switch, while the trapezoidal method is related to both; (c) The switch of the converter is turned off or the equivalent current source of the supporting capacitor of the converter is only related to the voltages at two ends, so that the calculation of the current flowing through the switch or the capacitor of the converter is avoided, and the operation amount is reduced.
(8) The high-efficiency simulation method provided by the invention has strong universality and is suitable for a distributed grid-connected system of any converter group (IGBT, thyristor, diode, ideal switch and the like) of the power electronic switch; and the algorithm is simple in organization, high in simulation efficiency and precision, and can simulate the behavior characteristics of a large system, the internal electrical transient characteristics of the converter module and the like.
Drawings
Fig. 1 is a primary structural diagram of a distributed grid-connected system of a converter group.
Fig. 2 shows the topology of the kth converter.
Fig. 3 is an equivalent circuit of a switch and a supporting capacitor of the kth converter.
Fig. 4 is a noon equivalent circuit of the kth converter.
Fig. 5 is an equivalent circuit of a distributed grid-connected system of the converter group.
Detailed Description
It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making creative efforts based on the embodiments of the present invention are within the protection scope of the present invention.
The technical scheme of the invention is a high-efficiency simulation method of a distributed grid-connected system of a converter group, which comprises the following steps:
s1, before simulation starts, setting simulation step length, simulation total duration and parameters of a multi-converter centralized grid-connected system, wherein the parameters of the multi-converter centralized grid-connected system comprise a power grid, supporting capacitors of the converters and the like;
s2, calculating equivalent admittance of a unified switch (any one of a diode, an IGBT, a thyristor and an ideal switch) of all converters and a supporting capacitor: according to the position of the converter connected with the power grid, an equivalent circuit model of a single converter is established, and the switch equivalent admittance of the converter is determined through simulation comparison and debugging; determining the equivalent admittance of a supporting capacitor of the current transformer;
s3, establishing a unified node admittance matrix of all the converters; according to the Norton theorem, calculating to obtain the equivalent admittance of the Norton equivalent circuit unified by all the converters;
s4, establishing an equivalent circuit of the multi-converter centralized grid-connected system;
S5, recording simulation initial time, initializing the switch state of each converter, reducing the current simulation time by one simulation step length time, and flowing the switch current, the voltages at two ends of the switch and the voltages at two ends of the supporting capacitor of each converter;
S6, calculating the equivalent current of each switch of each converter at the moment according to each switch state of each converter and the equivalent admittance of the converter switch and the supporting capacitor calculated in the step 2; calculating the equivalent current of each converter supporting capacitor at the moment;
and s7, calculating to obtain the equivalent current sources of the Norton equivalent circuits of the converters according to the Norton theorem.
S8, solving a node admittance network equation of the equivalent circuit of the multi-converter centralized grid-connected system established in the step 4 according to the system node admittance matrix obtained in the step 3 and the equivalent current sources of the Norton equivalent circuits of all the converters obtained in the step 7, and calculating to obtain unified grid-side voltages of all the converters;
s9, substituting the calculated unified network side voltage of all the converters into an admittance network equation of each converter node, and solving to obtain the current flowing through each switch of each converter, the voltages at two ends of the switch and the voltages at two ends of the supporting capacitor;
S10, adding a simulation step length moment to the current simulation moment, judging whether the simulation time length exceeds the set total simulation time length, if not, controlling the switch of each converter, determining the switch state of each converter by combining the power electronic switch characteristic, and turning to the step 6; if so, the simulation ends.
In the first embodiment, as shown in fig. 1 and fig. 2, the primary structure diagram of the current transformer group distributed grid-connected system and the topology structure diagram of the kth current transformer are shown, and in the figures, V s、isk is the grid-side voltage and the grid-side current of the kth current transformer, respectively.
Based on the backward Euler method and the on/off characteristics of the power electronic switch, the invention derives and adopts the branch of the parallel admittance of the current source to simulate the power electronic switch (diode, IGBT, thyristor, ideal switch, etc.), the supporting capacitor, etc. in the converter, as shown in figure 3 (the power electronic switch 1, the power electronic switch 2, the power electronic switch 3, the power electronic switch 4, the supporting capacitor are sequentially arranged from left to right and from top to bottom, m, n, o, p are nodes at two ends of the component, n is the input end of the equivalent circuit, p is the output end of the equivalent circuit), and the on or off states of the power electronic switches of various types are determined by external control and the characteristics of the power electronic switch. The switch equivalent admittance Gsk in fig. 3 is a constant greater than 0 and less than 1, the state of the switch has no influence on the constant, but the converter has influence on different grid-connected positions, namely, the switch equivalent admittances of the converters at different positions are different; the state of the switch affects the current sources, i k1～ik4 in fig. 3 is the equivalent current source of switches 1 to 4, respectively, taking the current sources connected at m and n points as an example, when the switch is turned on, the following relation is derived:
ik1(t)＝imn(t-Δt) (1)
when the switch is turned off, there is the following relationship:
ik1(t)＝-Gsk×Vmn(t-Δt) (2)
Wherein im n is the current flowing through the converter switch 1; i k1、Vmn is a current source connected to the m and n terminals and the voltages at two ends of the current source; t is simulation time; Δt is the simulation time step.
For the support capacitance, there is the following relation:
Wherein i kc、Gsc is the equivalent current source and admittance of the supporting capacitor of the converter respectively; c is the value of the supporting capacitor; v mo is the voltage between the m and o terminals.
According to fig. 3, based on the modified node method, the node admittance network equation of the kth converter can be written:
Wherein V m、Vn、Vp is the voltage of the node m, n, p point to the reference node O. And similarly, node admittance network equations of other converters can be obtained.
From fig. 3, a noon equivalent circuit of the kth converter can be obtained, as shown in fig. 4.
In fig. 4, the current source i k is the short-circuit current when the ports n, p of fig. 5 are short-circuited; g k is the input admittance after all independent sources 0 inside ports n, p of fig. 4.
The converter of fig. 1 is replaced by the converter noon equivalent circuit of fig. 4 instead of the converter model of fig. 2, and then the converter models are combined to obtain an equivalent circuit of the converter group distributed grid-connected system, as shown in fig. 5:
In fig. 5, i x、GX、VSX represents the noon equivalent current source, admittance and network side input voltage of each converter, x e N +, respectively.
According to the modeling, the high-efficiency simulation method for the distributed grid-connected system of the converter group comprises the following steps:
(1) Setting parameters such as simulation step length delta t, simulation total duration t f, supporting capacitance of a power grid and a converter and the like;
(2) Converter switch and support capacitance equivalent admittance calculation: (a) According to the access position of each converter, the power grid is respectively connected with the original model of the converter of the single figure 2 and the equivalent model of the figure 3, and the switch equivalent admittance of each converter is determined through simulation comparison and debugging and is marked as G s1、Gs2、Gsk......Gsx; (b) Determining the equivalent admittance G SC of the supporting capacitor of the converter according to the formula (3);
(3) Establishing an admittance matrix of each converter node shown in the formula (4); according to the Norton theorem, calculating to obtain the equivalent admittance G 1、G2......GX of the Norton equivalent circuit unified by all the converters;
(4) Establishing a node admittance matrix of an equivalent circuit of the multi-converter centralized grid-connected system shown in fig. 5;
(5) The initial simulation time is t, the switch state of each converter and the voltage at two ends of the switch flowing through the switch current and the voltage at the time t-delta t are initialized; initializing the voltages at two ends of the supporting capacitor of each converter at the moment of t-delta t;
(6) Calculating the equivalent current of each switch of each converter at the time t through (1) to (2) according to each switch state of each converter and the equivalent admittance of the converter switch and the supporting capacitor calculated in the step 2; calculating equivalent current i 1、i2......ix of each converter supporting capacitor at the time t by the formula (3);
(7) According to the Norton theorem, calculating to obtain an equivalent current source of the Norton equivalent circuit of each converter;
(8) According to the system node admittance matrix obtained in the step 4 and the equivalent current sources of the Norton equivalent circuits of the converters obtained in the step 7, solving a node admittance network equation of the equivalent circuits of the distributed grid-connected system of the converter group shown in fig. 5, and calculating to obtain the network side voltage V s1、VS2......VSX of each converter;
(9) Substituting the calculated network side voltage V s1、VS2......VSX of each converter into the admittance network equation of each converter node established in the step 3, and solving to obtain the current flowing through each switch of each converter at the moment t, the voltages at the two ends of the switch and the voltages at the two ends of the supporting capacitor in a similar formula (4);
(10) t' =t+Δt, judging whether the simulation duration exceeds the set total simulation duration t f, if not, controlling the switch of each converter, determining the switch state of each converter by combining the power electronic switch characteristic, and turning to step 6; if t f is exceeded, the simulation ends.
The high-efficiency simulation method provided by the invention has strong universality and is suitable for a multi-converter centralized grid-connected system of any power electronic switch (IGBT, thyristor, diode, ideal switch and the like); and the algorithm is simple in organization, high in simulation efficiency and precision, and can simulate the behavior characteristics of a large system, the internal electrical transient characteristics of the converter module and the like.
The foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the invention, but rather is intended to cover any equivalents of the structures or equivalent processes disclosed herein or in the alternative, which may be employed directly or indirectly in other related arts.
Claims (2)
1. The high-efficiency simulation method of the distributed grid-connected system of the current transformer group is characterized by firstly establishing an equivalent circuit model of an original circuit model of a single current transformer, and then establishing a distributed grid-connected simulation system model of the current transformer group comprising a plurality of Norton equivalent circuits, wherein the equivalent circuit model for establishing the actual circuit model of the single current transformer is based on a backward Euler method and the on/off characteristics of a power electronic switch, deducing and adopting 2 nodes and 2 branches of current source parallel admittances to establish an equivalent circuit of an internal power electronic switch and a supporting capacitor of the current transformer; establishing a Norton equivalent circuit of a single converter, wherein the Norton equivalent circuit replaces an actual circuit of the converter to obtain a distributed grid-connected simulation system model of the converter group;
The simulation is carried out through the simulation system model, and the method comprises the following steps:
Step 1, before simulation starts, setting parameters of a simulation step delta t, a simulation total duration t f, a converter and a converter group distributed grid-connected system;
Step 2, calculating equivalent admittance of the converter switch and the supporting capacitor: according to the position of the current transformer connected with the power grid, the power grid is respectively connected with an original model and an equivalent circuit model of a single current transformer, the switch equivalent admittance G s1、Gs2、Gsk......Gsx of each current transformer is determined through simulation comparison and debugging, x is the number of the current transformers, and k is any one of the current transformers;
step 3, establishing an admittance matrix of each converter node; according to the Norton theorem, calculating to obtain the equivalent admittance G 1、G2......GX of the Norton equivalent circuit of each converter;
step4, establishing a node admittance matrix of an equivalent circuit of the converter group distributed grid-connected system;
Step 5, initializing the switch state of each converter and flowing the switch current and the voltage at two ends of the switch at the moment t-delta t when the initial simulation moment is t; initializing the voltages at two ends of the supporting capacitor of each converter at the moment of t-delta t;
Step 6, calculating the equivalent current of each switch of each converter at the moment t and the equivalent current i 1、i2......ix of each converter supporting capacitor at the moment t according to each switch state of each converter and the equivalent admittance of the converter switch and the supporting capacitor calculated in the step 2;
step 7, calculating to obtain an equivalent current source of the Norton equivalent circuit of each converter according to the Norton theorem;
Step 8, solving a node admittance network equation of the equivalent circuit of the distributed grid-connected system of the converter group according to the system node admittance matrix obtained in the step 4 and the equivalent current sources of the Norton equivalent circuits of the converters obtained in the step 7, and calculating to obtain the network side voltage V s1、VS2......VSX of each converter;
Step 9, substituting the calculated grid-side voltage V s1、VS2......VSX of each converter into an admittance network equation of each converter node, and calculating the current flowing through each switch of each converter, the voltages at two ends of the switch and the voltages at two ends of a supporting capacitor at the moment t;
Step 10, t' =t+Δt, and judge whether the emulation duration exceeds the total emulation duration t f of settlement, if not exceed, by the switch control of every converter, and combine the power electronic switching characteristic, confirm every converter on-off state, and go to step 6; if the simulation time exceeds t f, the simulation is ended;
Based on the backward Euler method and the on/off characteristics of the power electronic switch, deriving and adopting a branch circuit of parallel admittance of a current source to simulate the power electronic switch and a supporting capacitor in the converter, wherein an equivalent circuit comprises four parallel equivalent current sources and admittances, and when the switch is conducted, the corresponding equivalent current flowing through the equivalent circuit is obtained through calculation according to the following relation:
ik1(t)＝imn(t-Δt) (1)
When the switch is off, the equivalent current is calculated by the following relation:
ik1(t)＝-Gsk×Vmn(t-Δt) (2)
Wherein G sk is a constant greater than 0 and less than 1, and i mn is a current flowing through a kth converter switching tube in the m and n end points; i k1、Vmn is a current source connected to the m and n terminals and the voltages at two ends of the current source; t is simulation time; Δt is the simulation time step;
for the support capacitance, the corresponding equivalent current and equivalent admittance are calculated by the following relation:
Wherein i kc、Gsc is the equivalent current source and admittance of the supporting capacitor of the kth converter respectively; c is the value of the supporting capacitor; v mo is the voltage between the m and o terminals;
based on the improved node method, the node admittance network equation of the kth converter is as follows (4):
Wherein V m、Vn、Vp is the voltage of the node m, n and p to the reference node respectively; and similarly, node admittance network equations of other converters can be obtained, and network side voltages of the converters are obtained through calculation in the formula (4).
2. The method for efficient simulation of a distributed grid-connected system of a current transformer group according to claim 1, wherein the switch is any one of a diode, an IGBT, a thyristor and an ideal switch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110234479.5A CN112966463B (en) | 2021-03-03 | 2021-03-03 | Efficient simulation method for distributed grid-connected system of converter group |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110234479.5A CN112966463B (en) | 2021-03-03 | 2021-03-03 | Efficient simulation method for distributed grid-connected system of converter group |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112966463A CN112966463A (en) | 2021-06-15 |
| CN112966463B true CN112966463B (en) | 2024-06-18 |
Family
ID=76276643
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110234479.5A Active CN112966463B (en) | 2021-03-03 | 2021-03-03 | Efficient simulation method for distributed grid-connected system of converter group |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112966463B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110021929A (en) * | 2018-12-29 | 2019-07-16 | 国网内蒙古东部电力有限公司经济技术研究院 | A kind of high-speed switch type fault current limiter electro-magnetic transient time-domain-simulation modeling method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110895644A (en) * | 2018-09-12 | 2020-03-20 | 中车株洲电力机车研究所有限公司 | Simulation system for large-scale converter group grid connection and equivalent circuit of converter |
| US20210049313A1 (en) * | 2019-08-16 | 2021-02-18 | Shanghai Jiao Tong University | Electromagnetic transient simulation method for field programmable logic array |
-
2021
- 2021-03-03 CN CN202110234479.5A patent/CN112966463B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110021929A (en) * | 2018-12-29 | 2019-07-16 | 国网内蒙古东部电力有限公司经济技术研究院 | A kind of high-speed switch type fault current limiter electro-magnetic transient time-domain-simulation modeling method |
Non-Patent Citations (1)
| Title |
|---|
| 面向工程的模块化多电平换流器建模与仿真;郭洪英;;数字技术与应用;20161015(10);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112966463A (en) | 2021-06-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106649927B (en) | FPGA-based real-time simulation combined modeling method for power electronic element | |
| CN103116665B (en) | A kind of MMC topological transformation device high-efficiency electromagnetic transient emulation method | |
| CN105117543B (en) | A kind of equivalent simulation method based on full-bridge submodule MMC for considering a variety of locking mode | |
| CN106446473B (en) | MMC real-time simulation modeling method and system | |
| CN108229021B (en) | Blocking modeling method of modular multilevel converter based on real-time digital simulator | |
| CN107609283A (en) | Modularization multi-level converter High Efficiency Modeling method based on bridge arm equivalent capacitance | |
| CN104820373A (en) | Simulation experiment platform and method for modularized multilevel converter | |
| CN103593520A (en) | Equivalent simulation calculation modeling method for modularized multi-level converter | |
| CN102663174A (en) | Simulation method of MMC (modular multilevel converter) and application thereof | |
| CN110489806B (en) | Electromagnetic transient modeling and calculating method for power grid comprising multi-voltage-source converter | |
| CN103605850A (en) | MMC (modular multilevel converter) equivalent modeling method with module latching function | |
| CN108897908A (en) | A kind of MMC real-time simulation modeling method of the function containing Pressure and Control | |
| CN115562069A (en) | RT-LAB-based energy storage grid-connected test system and test method thereof | |
| CN110895644A (en) | Simulation system for large-scale converter group grid connection and equivalent circuit of converter | |
| CN112966463B (en) | Efficient simulation method for distributed grid-connected system of converter group | |
| CN108460181A (en) | A kind of linear equal pressure sequence algorithm being suitable for half, full-bridge submodule mixed type MMC Dai Weinan equivalent models | |
| CN112464604B (en) | Efficient simulation method for multi-converter centralized grid-connected system | |
| CN110569558B (en) | Hybrid electromagnetic transient simulation method suitable for micro-grid real-time simulation | |
| CN113158617B (en) | General decoupling method and system for electromagnetic transient simulation of voltage source type converter | |
| CN112001142B (en) | Real-time simulation method of half-bridge type modular multilevel converter | |
| CN112052638B (en) | Real-time simulation method for full-bridge modular multilevel converter | |
| CN111898282B (en) | Improved modularized multi-level converter Thevenin equivalent modeling method | |
| CN115618701A (en) | MMC (Modular multilevel converter) low-dimensional admittance electromagnetic transient modeling simulation method and device and related equipment | |
| CN110968973A (en) | Simulation method and control method for transformer model, electronic device and storage medium | |
| Wang et al. | General Equivalent Modeling Method Suitable for DAB under Different Cascaded Modes |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant |