Multi-port inverter topology derivation method based on power flow matrix

Abstract

The invention discloses a multi-port inverter topology derivation method based on a power flow path matrix, and the method comprises the steps: firstly, converting all components in a circuit, such as a DC source, an AC output, a diode, and an active switching tube, into corresponding elements in the power flow path matrix; converting components through which a plurality of power paths in the multi-port inverter pass into corresponding row matrixes, and further obtaining a power flow path matrix; secondly, modeling based on a power flow path matrix, and converting a circuit constraint of the multi-port inverter into a constraint on the matrix; enabling the matrix to meet all matrix constraints through initialization setting and modification operation of the matrix; and finally, converting the diversified power flow path matrix meeting the constraint condition into an actual circuit topology to obtain a multi-port inverter topology.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of power electronic topology, and more specifically relates to a multi-port inverter topology derivation method based on a power flow matrix. BACKGROUND

[0002] With the improvement of environmental awareness and the increasing shortage of traditional fossil energy, renewable energy systems have become an ideal solution to alleviate environmental pollution and energy shortage problems. However, the acquisition of renewable energy depends on unpredictable natural conditions, resulting in intermittency and randomness of its output. Among various renewable energy systems, hybrid renewable energy systems, by integrating multiple energy sources, have become an effective alternative solution to solve the drawbacks of single energy systems.

[0003] As the core supporting component of hybrid renewable energy systems, power electronic interfaces have received widespread attention due to their ability to achieve efficient and controllable energy conversion. Currently, multi-port inverters have attracted widespread attention due to their high integration, high efficiency, and low cost by eliminating the intermediate DC-DC power conversion stage. However, as this type of converter is a new technology, the available topology structures are very limited. Therefore, how to derive diversified multi-port inverters has become a problem to be solved.

[0004] Currently, the mainstream multi-port inverter topology derivation method is based on existing multi-level inverters and graph theory-based topology derivation methods. The former is obtained by replacing the DC bus capacitor with a DC power supply. However, this method relies on existing topology structures, limiting the flexibility of power flow path design. Meanwhile, some special devices in multi-level inverters have functional redundancy in single-stage multi-port inverters, increasing the weight and cost of the system. The graph theory-based topology derivation method can optimize the number and type of devices, but it does not consider the reachability and controllability of the inverter power flow path, which may compromise the effectiveness of the derived topology. Therefore, it is necessary to verify and select effective topologies one by one, which is a tedious and inefficient process.

[0005] In contrast, the topology derivation method based directly on the power flow path matrix can intuitively model the reachability and controllability of the power flow path, ensuring the effectiveness of the derived topology. SUMMARY

[0006] The present application aims to overcome the shortcomings of the prior art and provide a multi-port inverter topology derivation method based on a power flow path matrix, which can derive diversified multi-port inverters.

[0007] To achieve the above-mentioned application purposes, the present application provides a multi-port inverter topology derivation method based on a power flow path matrix, characterized by the following steps:

[0008] (1), each component in the multi-port inverter is modeled as an element in the power flow path matrix, that is, the power flow path matrix modeling;

[0009] (2), the circuit constraints of the multi-port inverter are converted into the constraints of the power flow path matrix;

[0010] (3), the power flow path matrix is derived based on the constraints of the power flow path matrix;

[0011] (4), the power flow path matrix is converted into the topology graph of the multi-port inverter.

[0012] The purpose of the application is achieved as follows:

[0013] The multi-port inverter topology derivation method based on the power flow path matrix of the application firstly converts each component in the circuit, such as the DC source, AC output, diode, and active switch tube, into the corresponding element in the power flow path matrix, and converts the components through which the multiple power paths in the multi-port inverter pass into the corresponding row matrix, and further obtains the power flow path matrix; then the circuit constraints of the multi-port inverter are converted into the constraints of the matrix based on the power flow path matrix modeling; then the matrix is initialized and modified to meet all the matrix constraints; finally, the diversified power flow path matrix satisfying the constraint condition is converted into the actual circuit topology, and the multi-port inverter topology is obtained.

[0014] Meanwhile, the multi-port inverter topology derivation method based on the bipartite graph of the application also has the following beneficial effects:

[0015] (1), the application derives a new topology structure by constructing a power flow path matrix, without relying on the existing inverter structure;

[0016] (2), the application provides a modeling based on the power flow path matrix, which provides a basis for computer-aided derivation without the need for a large amount of manual participation;

[0017] (3), the application converts the topology derivation process into the initialization setting and modification operation of the power flow path matrix, directly ensuring the reachability and controllability of the power flow path, and ensuring the feasibility of the multi-port inverter;

[0018] (4), the application can quickly obtain the topology of the corresponding number of DC sources by increasing the rows of the power flow path matrix, has good scalability, and is suitable for any number of source occasions. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the flow chart of the multi-port inverter topology derivation method based on the power flow path matrix of the application;

[0020] Figure 2 is a schematic diagram of modeling a multi-port inverter as a power flow path matrix, wherein (a) is a schematic diagram of power flow paths of each component, (b) is a schematic diagram of power flow of the multi-port inverter topology in operation, (c) is a schematic diagram of power flow paths of the multi-port inverter topology, and (d) is a schematic diagram of converting the power flow paths into a row matrix and obtaining a final power flow matrix;

[0021] Figure 3 is a schematic diagram of power flow path matrix constraints, wherein (a) is a schematic diagram of matrix constraint 1 of a circuit structure violating a short circuit of a component, (b) is a schematic diagram of matrix constraint 3 of a circuit structure violating a short circuit of a DC source, (c) is a schematic diagram of matrix constraint 4 of a circuit structure violating a power flow discontinuity, and (d) is a schematic diagram of matrix constraint 5 of a circuit structure violating a component redundancy;

[0022] Figure 4 is a flow chart of deriving a topology based on a power flow path matrix, wherein (a) is a schematic diagram of initially setting a power flow path matrix according to actual application requirements, (b) is a schematic diagram of modifying a power flow path, and (c) is a schematic diagram of removing a power flow path matrix violating constraints 4 and 5 and converting a power flow path matrix meeting requirements into a feasible topology;

[0023] Figure 5 is a schematic diagram of a modification operation for eliminating violation of constraint 3;

[0024] Figure 6 is a schematic diagram of a matrix obtained after completion of the operation of eliminating violation of constraint 3, wherein (a) is a matrix obtained after completion of the operation of eliminating violation of constraint 3 and a corresponding topology, (b) and (c) are a new matrix obtained by further modifying the matrix of (a) and a corresponding topology, respectively;

[0025] Figure 7 is a schematic diagram of feasible topologies converted from all 2-DC source power flow path matrices meeting requirements; DETAILED DESCRIPTION

[0026] The specific embodiments of the present application will be described below with reference to the accompanying drawings, so that those skilled in the art can better understand the present application. It should be particularly noted that, in the following description, when detailed descriptions of known functions and designs may obscure the main content of the present application, these descriptions will be omitted here.

[0027] EMBODIMENT

[0028] In this embodiment, as shown in Figure 1 the present application is a multi-port inverter topology derivation method based on a bipartite graph, comprising the following steps:

[0029] (1) Each component in the multi-port inverter is modeled as an element in the power flow path matrix, i.e. power flow path matrix modeling, and the specific modeling process is as follows:

[0030] (1.1) As shown in Figure 2 (a. 1), the DC source power flow direction is converted into a solid line directed power flow path; as shown in Figure 2 (a. 2), the AC output is converted into the end of the power flow path for the inverter power output; as shown in Figure 2 (a. 3), the diode power flow direction is converted into a dashed line directed power flow path; as shown in Figure 2 (a. 4), the active switch tube is composed of a one-way controllable switch and an anti-parallel diode, which is converted into a solid line directed power flow path and a dashed line directed power flow path in parallel;

[0031] (1.2) As shown in Figure 2 (b) and 2(c), each power flow involved component in the multi-port inverter during operation is converted into a power flow path;

[0032] (1.3) As shown in Figure 2 (c) and 2(d), each power flow path is converted into a row matrix, wherein when the directed power flow path is an element in the solid line matrix, it is recorded as 1, and when the directed power flow path is an element in the dashed line matrix, it is recorded as i;

[0033] (1.4) As shown in Figure 2 (d), the row matrix obtained by converting the power flow path between a single DC source and an AC output power interaction is combined into a power flow path matrix, wherein the matrix converted from the DC source is recorded as a source matrix, the matrix converted from the component transmitting power from the positive electrode of the DC source to the AC output is recorded as a forward matrix, and the matrix converted from the component transmitting reverse power from the AC output to the negative electrode of the DC source is recorded as a reverse matrix;

[0034] (2) The circuit constraints of the multi-port inverter are converted into the constraints of the power flow path matrix;

[0035] (2.1) The components cannot be short-circuited, as shown in Figure 3 (a), matrix constraint 1 is obtained: there cannot be a column of 0 elements in the middle of two columns of elements that are not 0 and the same in the forward and reverse matrices;

[0036] (2.2) Each power flow path must be controllable, and matrix constraint 2 is obtained: each row in the forward or reverse matrix must have at least one 1;

[0037] (2.3) The DC sources cannot be short-circuited, as shown in Figure 3As shown in (b), we obtain matrix constraint 3: arbitrarily select two rows from the forward matrix, denoted as P. x P y Where x > y, if there exists a column S in the two rows x P has the same elements and is not 0. y Line S x There must be at least one 'i' before the first column; if no two rows have the same non-zero element in a certain column, the second row must have at least one 'i'.

[0038] (2.4) The power flow must remain continuous, such as Figure 3 As shown in (c), matrix constraint 4 is obtained: In the forward and reverse matrices, if there are two columns with the same column indices, both being S... x Then the column labels between these two columns must also appear in pairs;

[0039] (2.5) Device redundancy, such as Figure 3 As shown in (d), matrix constraint 5 is obtained: in the forward matrix, each row has at most one unique non-zero element;

[0040] (3) The power flow path matrix is ​​derived based on the power flow path matrix constraint;

[0041] (3.1) First determine the number of DC sources of the multi-port inverter, denoted as D. Then initialize the power flow path matrix: the source matrix and the forward matrix are D-dimensional identity matrices, and the reverse matrix is ​​a D×1 dimension all-1 matrix; initialize the matrix to satisfy constraints 1 and 2.

[0042] In this implementation case, such as Figure 4 As shown in (a), the number of DC sources is determined to be 2. The source matrix and forward matrix are initialized as 2-dimensional identity matrices, and the reverse matrix is ​​a 2×1 dimension all-1 matrix.

[0043] (3.2) Modify the matrix set during initialization, such as... Figure 4 As shown in (b);

[0044] (3.2.1) Modify any two rows of the forward and reverse matrices of the matrix obtained in step (3.1), and denote P as P. x P y Where x > y, such that the resulting matrix satisfies constraint 3, as shown below. Figure 4 As shown in (b), inserting column S4 makes the matrix satisfy constraint 3; there are 5 types of modification operations;

[0045] (3.2.1.1) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S xInsert a new column before the previous column; if it does not exist, insert a new column after the previous column; the elements of the new column are: P. x Behavior 0, P y Behavior i, P j The (j>y) row can be either 0 or i, other rows are 0;

[0046] like Figure 5 As shown in (b), a new column S4 is inserted into the forward matrix;

[0047] (3.2.1.2) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert a new column before the previous column; if it does not exist, insert a new column after the previous column; the elements of the new column are: P. x Line and P y Behavior 1, other behaviors 0; then P y Change the first element 1 before the newly inserted column to i;

[0048] like Figure 5 As shown in (b), insert a new column S4 into the forward matrix; modify the element in row P2 and column S3 to i;

[0049] (3.2.1.3) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert two new columns before the first column; if they do not exist, insert two new columns after the first column of the forward matrix; the element of the new first column is: P. y Behavior i, all other behaviors 0; the new second column element is: P x Line and P y Behavior 1, other behaviors 0;

[0050] like Figure 5 As shown in (c), insert two new columns S4 and S5 into the forward matrix;

[0051] (3.2.1.4) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert two new columns before the first column; if they do not exist, insert two new columns after the first column of the forward matrix; the element of the new first column is: P. y Behavior i, all other behaviors 0; the new second column element is: P x Behavior 1, P j The row with (y≥j>x) can be either 0 or 1, and the other rows are 0; a new column is inserted into the reverse matrix, and the elements of the new column are all i;

[0052] like Figure 5 As shown in (d), insert two new columns S4 and S5 into the forward matrix; insert a new column S5 into the reverse matrix.

[0053] (3.2.1.5) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert two new columns before the first column; if they do not exist, insert a new column after the first column of the forward matrix; the elements of the new column are: P. x Behavior 0, P y Behavior i, P j The (j>y) row can be either 0 or i, and the other rows are 0; a new column is inserted into the reverse matrix, and the elements of the new column are all 1s;

[0054] like Figure 5 As shown in (e), insert a new column S4 into the forward matrix; insert a new column S4 into the reverse matrix;

[0055] (3.2.2) Further modification; the matrix that satisfies the conditions in step (3.2.1) can be further modified to obtain a new matrix; the conditions are: there are two rows in the forward matrix, denoted as P. x P y Where x>y, P x P y Each has one column, denoted as S. m S n S m S n The row corresponding to the only non-zero element 1 is P. x and P y Additionally, P x P y There exists a column S j The elements are identical and not zero; a further modification is to delete column S of the matrix. n Or delete column S of the matrix j ;

[0056] like Figure 6 As shown, deleting column S2 or column S6 from matrix 6(a) yields new matrices 6(b) and 6(c), respectively.

[0057] (3.3) Remove matrices that violate constraints 4 and 5;

[0058] (4) Convert the power flow path matrix into a topology diagram of a multi-port inverter, such as... Figure 4 As shown in (c), the power flow path matrix that satisfies all matrix constraints is finally transformed into the topology of the multi-port inverter.

[0059] In this embodiment, the above steps can yield the following result: Figure 7 The diagram shows 11 multiport inverter topologies with two DC sources.

[0060] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are protected.

Claims

1. A method for topology derivation of a multi-port inverter based on a power flow matrix, characterized in that, Includes the following steps: (1) Model each component in the multi-port inverter as an element in the power flow path matrix, i.e., power flow path matrix modeling; (2) Convert the circuit constraints of the multi-port inverter into constraints of the power flow path matrix; (3) The power flow path matrix is ​​derived from the constraints of the power flow path matrix; (4) Convert the power flow path matrix into the topology of the multi-port inverter.

2. The multi-port inverter topology derivation method based on power flow matrix according to claim 1, characterized in that, The power flow path matrix modeling process is as follows: (2.1) Convert the DC power source into a solid directed power flow path according to the power flow direction; convert the AC output into the power output terminal of the inverter into the power flow path endpoint; convert the diode into a dashed directed power flow path according to the power flow direction; convert the active switching transistor into a solid directed power flow path connected in parallel with the dashed directed power flow path according to the active switching transistor being composed of a unidirectional controllable switch and an anti-parallel diode. (2.2) Convert the components involved in each power flow when the multi-port inverter is working into power flow paths; (2.3) Convert each power flow path into a row matrix, where a directed power flow path is an element in a solid line matrix and is denoted as 1, and a directed power flow path is an element in a dashed line matrix and is denoted as i. (2.4) The row matrices obtained by the power flow path transformation of a single DC source and AC output power interaction are merged into a power flow path matrix. The matrix obtained by the DC source transformation is called the source matrix, the matrix obtained by the DC source positive terminal to AC output power transmission component transformation is called the forward matrix, and the matrix obtained by the AC output to DC source negative terminal power transmission component transformation is called the reverse matrix.

3. The multi-port inverter topology derivation method based on power flow matrix according to claim 1, characterized in that, The method for converting the circuit constraints of the multi-port inverter into power flow path matrix constraints is as follows: (3.1) Components cannot be short-circuited, resulting in matrix constraint 1: There cannot be a column with 0 elements between two identical columns of forward and reverse matrices where the elements are not 0; (3.2) Each power flow path must be controllable, resulting in matrix constraint 2: each row of the forward or reverse matrix must have at least one 1; (3.3) DC sources cannot be short-circuited, resulting in matrix constraint 3: Take any two rows in the forward matrix, and denote P x P y Where x > y, if there exists a column S in the two rows x P has the same elements and is not 0. y Line S x There must be at least one 'i' before the first column; if no two rows have the same non-zero element in a certain column, the second row must have at least one 'i'. (3.4) The power flow must remain continuous, resulting in matrix constraint 4: In the forward and reverse matrices, if there are two columns with the same column indices, both being S... x Then the column labels between these two columns must also appear in pairs; (3.5) Device redundancy, resulting in matrix constraint 5: In the forward matrix, each row has at most one unique non-zero element.

4. The multi-port inverter topology derivation method based on power flow matrix according to claim 1, characterized in that, The process of deriving the power flow path matrix based on the power flow path matrix constraint is as follows: (4.1) First determine the number of DC sources of the multi-port inverter, denoted as D. Then initialize the power flow path matrix: the source matrix and the forward matrix are D-dimensional identity matrices, and the reverse matrix is ​​a D×1 dimension all-1 matrix; initialize the matrix to satisfy constraints 1 and 2. (4.2) Modify the matrix set during initialization; (4.2.1) Modify any two rows of the forward and reverse matrices of the matrix obtained in step (4.1), and denote P as P. x P y , where x>y, such that the matrix satisfies constraint 3; there are 5 types of modification operations; (4.2.1.1) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert a new column before the previous column; if it does not exist, insert a new column after the previous column; the elements of the new column are: P. x Behavior 0, P y Behavior i, P j Row selection is 0 or i, other rows are 0, j>y; (4.2.1.2) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert a new column before the previous column; if it does not exist, insert a new column after the previous column; the elements of the new column are: P. x Line and P y Behavior 1, other behaviors 0; then P y Change the first element 1 before the newly inserted column to i; (4.2.1.3) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert two new columns before the first column; if they do not exist, insert two new columns after the first column of the forward matrix; the element of the new first column is: P. y Behavior i, all other behaviors 0; the new second column element is: P x Line and P y Behavior 1, other behaviors 0; (4.2.1.4) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert two new columns before the first column; if they do not exist, insert two new columns after the first column of the forward matrix; the element of the new first column is: P. y Behavior i, all other behaviors 0; the new second column element is: P x Behavior 1, P j Rows can be either 0 or 1, other rows are 0, y≥j>x; insert a new column into the reverse matrix, the elements of the new column are all i; (4.2.1.5) In the forward matrix, if P x P y There exists a column S x If the elements are the same and not 0, S x Insert two new columns before the first column; if they do not exist, insert a new column after the first column of the forward matrix; the elements of the new column are: P. x Behavior 0, P y Behavior i, P j Rows can be either 0 or i, other rows are 0, j>y; insert a new column into the reverse matrix, the elements of the new column are all 1; (4.2.2) Further modification; the matrix that satisfies the condition in step (4.2.1) can be further modified to obtain a new matrix; the condition is: there are two rows in the forward matrix, denoted as P. x P y Where x>y, P x P y Each has one column, denoted as S. m S n S m S n The row corresponding to the only non-zero element 1 is P. x and P y Additionally, P x P y There exists a column S j The elements are identical and not zero; a further modification is to delete column S of the matrix. n Or delete column S of the matrix j ; (4.3) Remove matrices that violate constraints 4 and 5.

Images