A method for automatically constructing a dc-dc converter based on loop matrix
By using an automatic construction method based on loop matrices, the problems of slow design speed and high uncertainty in existing DC-DC converter technologies are solved, achieving fast and accurate converter generation, which is suitable for more complex converter designs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2023-03-16
- Publication Date
- 2026-04-17
AI Technical Summary
Existing technologies rely on the designer's experience when constructing DC-DC converters, resulting in slow design speeds, high uncertainty, and difficulty in obtaining all converters that meet the requirements.
An automatic construction method based on loop matrices is adopted to convert the volt-second balance equations or state equations into loop matrices. Through a series of steps, all DC-DC converters that conform to the loop matrix are generated, including the processing of the branch-node relationship matrix and the depth-first search algorithm.
It enables fast and deterministic DC-DC converter construction, can search for all suitable converters, is applicable to more complex converter constructions, and improves design efficiency and accuracy.
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Figure CN116432579B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of DC-DC converter topology construction, and in particular to an automatic construction method for DC-DC converters based on a loop matrix. Background Technology
[0002] The flux balance method and the state equation method are two representative methods for constructing DC-DC converters. The flux balance method, based on a given voltage gain expression, derives several volt-second balance equations, and then constructs a DC-DC converter corresponding to each volt-second balance equation set. The state equation method, based on given component types and quantities, derives several state equation sets, and then constructs a DC-DC converter corresponding to each state equation set. The volt-second balance equations describe the charging and discharging voltages of each inductor in different modes, further reflecting which components belong to the same loop. The state equations reflect the connection relationships of each component in each mode. Therefore, both the volt-second balance equations and the state equations can be transformed into loop matrices of the DC-DC converter in each mode.
[0003] Of the two construction methods described above, the process of deriving the volt-second balance equations or state equations from known conditions is relatively complete, while the process of deriving the DC-DC converter from these equations is somewhat difficult. Designers typically draw equivalent circuit diagrams for each mode without switching devices based on the volt-second balance equations or state equations, and then add switching transistors and diodes to the circuit to conform to the corresponding modes, thus forming a complete DC-DC converter. However, this process lacks explicit steps and usually requires designers to draw diagrams manually, try adding switching transistors and diodes to different locations, and verify the results. This design method heavily relies on the designer's experience, resulting in slow design speed, high uncertainty, and difficulty in obtaining all compliant DC-DC converters. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of existing technologies and propose an automatic construction method for DC-DC converters based on loop matrices. This method converts the volt-second balance equations or state equations into loop matrices for each mode, outputting all corresponding DC-DC converters. This method is applicable to the construction process of both flux balance design and state equation methods.
[0005] To achieve the above objectives, the technical solution provided by this invention is: an automatic construction method for DC-DC converters based on loop matrices. This method utilizes two-mode loop matrices, namely mode 1 loop matrices and mode 2 loop matrices, generated by the flux balance design method or the state equation method, to construct all DC-DC converters that conform to the loop matrices. The method includes the following steps:
[0006] 1) Transform the modal-1 loop matrix into a branch-node relationship matrix;
[0007] 2) For each branch-node relationship matrix in step 1), add a switch to each basic loop to obtain a new branch-node relationship matrix;
[0008] 3) For each branch-node relationship matrix in step 2), select two non-adjacent nodes and connect a diode in parallel until the number of diodes is the same as the number of switching transistors, to obtain a new branch-node relationship matrix;
[0009] 4) For each branch-node relationship matrix in step 3), disconnect the switch, short-circuit the diode, and delete other incomplete branches;
[0010] 5) For each branch-node relationship matrix processed in step 4), use the depth-first search algorithm to search for loops in the topology and form a loop matrix. Compare the obtained loop matrix with the mode 2 loop matrix. If they are the same, backtrack to the branch-node relationship matrix containing the switching transistor and diode obtained in step 3). Otherwise, end the process.
[0011] 6) For the branch-node relationship matrix processed in step 5), filter out redundancy caused by different node numbers;
[0012] 7) For each branch-node relationship matrix processed in step 6), determine the orientation of the switching transistor and diode;
[0013] 8) For each branch-node relationship matrix processed in step 7), filter out circuits that cannot work properly due to the simultaneous conduction of diodes and switching transistors, and finally output a DC-DC converter that can work properly and corresponds to the given loop matrix.
[0014] Further, in step 1), based on the modal 1 loop matrix in the given loop matrix, the branches are divided into two categories according to their positions in the loop: unique branches belonging to a single loop and common branches belonging to multiple loops; based on the classification, a circuit conforming to the modal 1 loop matrix is constructed, represented by a branch-node relationship matrix, and the resulting branch-node relationship matrix is stored in list a.
[0015] In this context, the loop matrix of a certain mode represents the branches and their directions contained in each loop in the equivalent circuit under that mode, with one element considered as one branch; the reference directions of inductors, switches, and diodes are the directions of current flow, and the reference directions of voltage sources and capacitors are the directions of potential from low to high; the loop matrix is transformed into a basic loop matrix with inductors as the connecting branches, and the reference direction of each basic loop in the basic loop matrix is the direction of the corresponding connecting inductor; if the equivalent circuit under a certain mode has l basic loops and r elements, then the corresponding basic loop matrix is of order l×r;
[0016] The branch-node relationship matrix represents the connection relationship between branches and nodes. The branch-node relationship matrix is of order r×2, and each row represents a branch. The two elements in the matrix represent the two nodes connected by the branch. A branch-node relationship matrix uniquely corresponds to a circuit topology.
[0017] Furthermore, in step 2), for each branch-node relationship matrix in list a, a traversal algorithm is used to select a branch in each basic loop and add a switch connected in series with it. The resulting new branch-node relationship matrix is stored in list b.
[0018] Furthermore, in step 3), for each branch-node relationship matrix in list b, a traversal algorithm is used to select two non-adjacent nodes, and then a diode is connected in parallel between the two nodes. This step is repeated until the number of diodes is the same as the number of switching transistors. The resulting new branch-node relationship matrix is stored in list c.
[0019] Further, in step 4), for each branch-node relationship matrix in list c, the switch is disconnected and removed from the branch-node relationship matrix, and other branches with incomplete connections are also removed; the diode is short-circuited and removed from the branch-node relationship matrix, the nodes at both ends of the diode are merged, and other short-circuited branches are removed; since some nodes have disappeared, the nodes are renumbered starting from 0; if a branch is missing compared to the branches contained in the mode 2 loop matrix, or if there are two or more inductors in parallel, then the branch-node relationship matrix is filtered out; the branch-node relationship matrices that are not filtered out are stored in list d, and at the same time, the positions of the prototypes of the switch and diode in list c are stored in list d'.
[0020] Furthermore, in step 5), for each branch-node relationship matrix in list d, a depth-first search algorithm is used to search for loops in the topology and form a loop matrix. The obtained loop matrix is compared with the modality 2 loop matrix. If they are the same, the corresponding branch-node relationship matrix in list c is backtracked according to the position information stored in list d' and stored in list e. Otherwise, the process ends.
[0021] Furthermore, in step 6), for the branch-node relationship matrix in list e, redundancy caused by different node numbers is filtered out, and the non-redundant branch-node relationship matrix is stored in list f.
[0022] Furthermore, in step 7), for each branch-node relationship matrix in list f, the orientation of the switching transistor and diode is determined according to the following rules:
[0023] ① A switching transistor that belongs to a specific branch or common branch of a circuit as the power supply, and whose direction is the same as that of the power supply;
[0024] ② The currents in inductors L1 and L2 must remain in the same direction in both modes, while the currents in capacitor C1 must remain in opposite directions in both modes;
[0025] ③ Avoid short-circuiting the power supply through the switching transistor or diode;
[0026] The branch-node relationship matrix after determining the direction of the switching transistor and diode is still stored in list f.
[0027] Further, in step 8), for each branch-node relationship matrix in list f, the diode is disconnected to obtain the equivalent circuit of mode 1. The potential of the nodes at both ends of the diode is calculated. If there is a positive potential difference, the diode and the switch are simultaneously turned on in mode 1. The branch-node relationship matrix corresponding to this circuit is then eliminated.
[0028] Finally, the branch-node relationship matrix that was not filtered out is output, and the corresponding DC-DC converter is constructed, that is, the DC-DC converter that can work normally and corresponds to the given loop matrix.
[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0030] 1. The automatic construction method of DC-DC converter based on loop matrix provided by the present invention has defined steps, and its implementation is fast after programming.
[0031] 2. The method of this invention comprehensively considers all arrangements of power supply, capacitor, and inductor and all positions of switching devices, and can search for all DC-DC converters that conform to a given two-mode loop matrix, resulting in a complete solution.
[0032] 3. The method of the present invention can be extended to the construction of DC-DC converters with more capacitors and inductors, which helps to construct more complex and better-performing DC-DC converters and has good application prospects. Attached Figure Description
[0033] Figure 1 This is a flowchart of the method of the present invention.
[0034] Figure 2This is the equivalent circuit diagram of mode 1 in the embodiment.
[0035] Figure 3 This is a circuit diagram with a switching transistor added in the embodiment.
[0036] Figure 4 This is a circuit diagram after adding diodes in the embodiment.
[0037] Figure 5 The circuit diagram shown in the embodiment is after removing the switching transistor and incomplete branches.
[0038] Figure 6 The circuit diagram is shown for one type of loop matrix in the embodiment.
[0039] Figure 7 The equivalent circuit diagrams for mode 1 (including the switching transistor) and mode 2 (including the diode) in the embodiments are shown.
[0040] Figure 8 This is a schematic diagram of the final DC-DC converter obtained in the embodiment. Detailed Implementation
[0041] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0042] The voltage gain expression is constructed using the flux balance design method as D. 2 This is a non-isolated DC-DC converter. Since the highest order of D is second-order, at least two capacitors and two inductors are required. From an economic perspective, this embodiment uses two capacitors, two inductors, one voltage source, and is configured with two switching transistors and two diodes. A set of volt-second balance equations obtained from the flux balance design method is as follows:
[0043]
[0044] Where D is the duty cycle of the switching transistor, D' = 1 - D. L1 v L2 The voltages of inductors L1 and L2 are respectively, V s V is the power supply voltage. C1 V C2 These are the voltages of capacitors C1 and C2, respectively. Equation (1) is transformed into a basic loop matrix with inductors as the connecting branches, which serves as a known condition for the implementation of this invention. Since there are two inductors, the equivalent circuit of each mode has two basic loops, and the loop matrix has 2 rows. Because the equivalent circuit does not contain switching transistors or diodes, but has 5 other components, the loop matrix has 5 columns. The transformed two-mode loop matrices are as follows:
[0045] Mode 1:
[0046]
[0047] Mode 2:
[0048]
[0049] Here, l1 and l2 are the numbers of the two basic loops.
[0050] The loop matrices of the two modes mentioned above are the given conditions for the automatic construction method of DC-DC converter based on loop matrix provided by the present invention. The method is implemented according to the following steps.
[0051] 1. Classify the branches of the mode 1 loop matrix. Loop 1-specific branches include: V s C2, L1; the unique branch of loop 2 is L2; the common branch is C1. Based on the above classification, the nodes in the circuit are numbered, thus transforming the mode 1 loop matrix into a branch-node relationship matrix and storing it in list a. After this step, list a contains 6 branch-node relationship matrices, one of which is:
[0052]
[0053] The corresponding circuit is as follows Figure 2 As shown.
[0054] 2. For each branch-node relationship matrix in list a, a traversal algorithm is used to select one branch in each basic loop and add a switch connected in series with it. The resulting new branch-node relationship matrix is stored in list b. After this step, list b contains 168 branch-node relationship matrices. For the branch-node relationship matrix shown in equation (4), a switch is added at the voltage source in basic loop l1 and at capacitor C1 in l2. The branch-node relationship matrix becomes:
[0055]
[0056] The newly added switch S is located in rows 6 and 7 of the branch-node relationship matrix. The corresponding circuit is as follows: Figure 3 As shown.
[0057] 3. For each branch-node relationship matrix in list b, a traversal algorithm is used to select two non-adjacent nodes, and then a diode is connected in parallel between the two nodes. Then, two more non-adjacent nodes are selected, and a diode is connected in parallel between them. The resulting new branch-node relationship matrix is stored in list c. After this step, list c contains 4704 branch-node relationship matrices. For the branch-node relationship matrix shown in equation (5), if diodes are connected in parallel between nodes [0 1] and [0 2] respectively, the branch-node relationship matrix becomes:
[0058]
[0059] The newly added diode VD is located in rows 8 and 9. The corresponding circuit is as follows: Figure 4 As shown.
[0060] 4. For each branch-node relationship matrix in list c, taking the matrix shown in equation (6) as an example, disconnect the switch and remove it from the branch-node relationship matrix, and remove the V with incomplete connection. s With branch C1, the branch-node relationship matrix becomes:
[0061]
[0062] The nodes connected to the removed branches are denoted as [-1 -1]. The corresponding circuit is as follows: Figure 5 As shown.
[0063] Short-circuit the diode and remove it from the branch-node matrix, merge the nodes at both ends of the diode, and remove other short-circuited branches. The branch-node matrix then becomes:
[0064]
[0065] The corresponding circuit has only two inductors connected in parallel.
[0066] Since nodes 1 and 2 have disappeared, the nodes are renumbered starting from 0. The branch-node relationship matrix becomes:
[0067]
[0068] After transformation, if a branch is missing compared to the branches included in the modal 2 loop matrix, or if there are two or more inductors connected in parallel, then the branch-node relationship matrix is filtered out. The branch-node relationship matrix shown in Equation (9) only has branches L1 and L2, and they are connected in parallel, while the modal 2 loop matrix shown in Equation (3) has branches C1, C2, L1, and L2, so it should be filtered out.
[0069] The remaining branch-node relationship matrices that were not filtered out are stored in list d, and the positions of their prototypes containing switches and diodes in list c are stored in list d'. After this step, list d contains 2608 branch-node relationship matrices, and list d' also contains 2608 positions.
[0070] 5. For each branch-node relationship matrix in list d, use a depth-first search algorithm to search for loops in the topology and form a loop matrix. For example, for a branch-node relationship matrix in list d:
[0071]
[0072] Two loops, 0-1-2-0 and 1-2-1, are found, or represented as C1-C2-L1 and C2-L2. These are converted into a loop matrix, with the inductor direction as the reference direction for the loops, as follows:
[0073]
[0074] The corresponding circuit is as follows Figure 6 As shown.
[0075] The obtained loop matrix is compared with the loop matrix of mode 2. If they are the same, the corresponding branch-node relationship matrix in list c is traced back according to the position information stored in list d' and stored in list e. The loop matrix shown in equation (11) is consistent with the loop matrix of mode 2 shown in equation (3). Therefore, a total of 7 corresponding branch-node relationship matrices are traced back from list c and stored in list e, as shown in Table 1.
[0076] Table 1 lists the 7 branch-node relationship matrices in list e.
[0077]
[0078] 6. For the branch-node relationship matrix in list e, remove redundancies caused by different node numbers, and store the non-redundant branch-node relationship matrices in list f. For example, in matrix 4 of Table 1, swapping the numbers of nodes 2 and 4 results in a matrix identical to matrix 1, meaning that matrices 1 and 4 correspond to the same circuits. Similarly, matrices 2 and 5, and 3 and 6 correspond to the same circuits. Therefore, after removing matrices 4, 5, and 6, the remaining matrices 1, 2, 3, and 7 are stored in list f.
[0079] 7. For each branch-node relationship matrix in list f, determine the orientation of the switching transistor and diode according to the following rules:
[0080] ① A switching transistor belonging to a specific branch or common branch of a circuit as the power supply, and its direction is the same as that of the power supply.
[0081] ② The currents in inductors L1 and L2 must remain in the same direction in both modes, while the currents in capacitor C1 must remain in opposite directions in both modes.
[0082] ③ Avoid short-circuiting the power supply through the switching transistor or diode.
[0083] For example, for matrix 1 in Table 1, removing the diode branch yields the equivalent circuit of mode 1 including the switching transistor, such as... Figure 7 As shown in (a); removing the switching transistor branch yields the equivalent circuit of mode 2 containing the diode, as follows. Figure 7As shown in (b). According to rule ①, the direction of S1 is determined to be [4 2], and thus the current direction of L1 is [2 3]. According to rule ②, the current direction of C1 mode 2 is
[30] , then the current direction of C1 mode 1 is [0 3], therefore the direction of S2 is [3 5]. According to the direction of S2, the current direction of L2 is determined to be [5 0], and thus the direction of VD2 is [1 5]. According to rule ③, the direction of VD1 is determined to be [1 2].
[0084] Therefore, the branch-node relationship matrix after determining the direction of the switching transistor and diode is shown in Table 2 and is still stored in list f.
[0085] Table 2 lists the four branch-node relationship matrices in list f.
[0086]
[0087] 8. For each branch-node relationship matrix in list f, disconnect the diode to obtain the equivalent circuit of mode 1. Calculate the potential of the nodes at both ends of the diode. If there is a positive potential difference, the diode and the switch are simultaneously conducting in mode 1. Eliminate the branch-node relationship matrix corresponding to this circuit.
[0088] The voltages across the two capacitors can be calculated using the given volt-second balance equations (1):
[0089]
[0090] Since the two inductors are located in different circuits, their voltages can be calculated using Kirchhoff's voltage law. Therefore, the potentials of each node can be calculated. Calculations show that the voltages of diodes [2 5] in matrix 3 and [5 1] in matrix 7 in mode 1 are both (1-D)V. s This causes the circuit to malfunction, preventing it from conducting properly. Therefore, matrices 3 and 4 are eliminated.
[0091] Finally, output the unfiltered matrices 1 and 2, and construct the corresponding DC-DC converter, i.e., the DC-DC converter that is required to function properly and corresponds to the given loop matrix, such as... Figure 8 As shown in (a) and (b).
[0092] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for automatic construction of a DC-DC converter based on a circuit matrix, characterized by, This method utilizes the two-mode loop matrices generated by the flux balance design method or the state equation method, namely the mode 1 loop matrix and the mode 2 loop matrix, to construct all DC-DC converters that conform to the loop matrix. It includes the following steps: 1) Transform the modal-1 loop matrix into a branch-node relationship matrix; 2) For each branch-node relationship matrix in step 1), add a switch to each basic loop to obtain a new branch-node relationship matrix; 3) For each branch-node relationship matrix in step 2), select two non-adjacent nodes and connect a diode in parallel until the number of diodes is the same as the number of switching transistors, to obtain a new branch-node relationship matrix; 4) For each branch-node relationship matrix in step 3), disconnect the switch, short-circuit the diode, and delete other incomplete branches; 5) For each branch-node relationship matrix processed in step 4), use the depth-first search algorithm to search for loops in the topology and form a loop matrix. Compare the obtained loop matrix with the mode 2 loop matrix. If they are the same, backtrack to the branch-node relationship matrix containing the switching transistor and diode obtained in step 3). Otherwise, end the process. 6) For the branch-node relationship matrix processed in step 5), filter out redundancy caused by different node numbers; 7) For each branch-node relationship matrix processed in step 6), determine the orientation of the switching transistor and diode; 8) For each branch-node relationship matrix processed in step 7), filter out circuits that cannot work properly due to the simultaneous conduction of diodes and switching transistors, and finally output a DC-DC converter that can work properly and corresponds to the given loop matrix.
2. The method of claim 1, wherein, In step 1), based on the modal 1 loop matrix in the given loop matrix, the branches are divided into two categories according to their position in the loop: unique branches belonging to a single loop and common branches belonging to multiple loops; based on the classification, a circuit conforming to the modal 1 loop matrix is constructed, represented by a branch-node relationship matrix, and the resulting branch-node relationship matrix is stored in list a. In this context, the loop matrix of a certain mode represents the branches and their directions contained in each loop in the equivalent circuit under that mode, with one element considered as one branch; the reference directions of inductors, switches, and diodes are the directions of current flow, and the reference directions of voltage sources and capacitors are the directions of potential from low to high; the loop matrix is transformed into a basic loop matrix with inductors as the connecting branches, and the reference direction of each basic loop in the basic loop matrix is the direction of the corresponding connecting inductor; if the equivalent circuit under a certain mode has l basic loops and r elements, then the corresponding basic loop matrix is of order l×r; The branch-node relationship matrix represents the connection relationship between branches and nodes. The branch-node relationship matrix is of order r×2, and each row represents a branch. The two elements in the matrix represent the two nodes connected by the branch. A branch-node relationship matrix uniquely corresponds to a circuit topology.
3. The automatic construction method for a DC-DC converter based on a loop matrix according to claim 2, characterized in that, In step 2), for each branch-node relationship matrix in list a, a traversal algorithm is used to select a branch in each basic loop and add a switch connected in series with it. The resulting new branch-node relationship matrix is stored in list b.
4. The automatic construction method for a DC-DC converter based on a loop matrix according to claim 3, characterized in that, In step 3), for each branch-node relationship matrix in list b, a traversal algorithm is used to select two non-adjacent nodes, and then a diode is connected in parallel between the two nodes. This step is repeated until the number of diodes is the same as the number of switching transistors. The resulting new branch-node relationship matrix is stored in list c.
5. The automatic construction method for a DC-DC converter based on a loop matrix according to claim 4, characterized in that, In step 4), for each branch-node relationship matrix in list c, the switch is disconnected and removed from the branch-node relationship matrix, and other branches with incomplete connections are also removed; the diode is short-circuited and removed from the branch-node relationship matrix, the nodes at both ends of the diode are merged, and other short-circuited branches are removed; since some nodes have disappeared, the nodes are renumbered starting from 0; if a branch is missing compared to the branches contained in the mode 2 loop matrix, or if there are two or more inductors in parallel, then the branch-node relationship matrix is filtered out; the branch-node relationship matrices that are not filtered out are stored in list d, and the positions of the prototypes of the switch and diode in list c are stored in list d'.
6. The automatic construction method for a DC-DC converter based on a loop matrix according to claim 5, characterized in that, In step 5), for each branch-node relationship matrix in list d, a depth-first search algorithm is used to search for loops in the topology and form a loop matrix. The obtained loop matrix is compared with the modality 2 loop matrix. If they are the same, the corresponding branch-node relationship matrix in list c is backtracked according to the position information stored in list d' and stored in list e. Otherwise, the process ends.
7. The automatic construction method for a DC-DC converter based on a loop matrix according to claim 6, characterized in that, In step 6), for the branch-node relationship matrix in list e, redundancy caused by different node numbers is filtered out, and the non-redundant branch-node relationship matrix is stored in list f.
8. The automatic construction method for a DC-DC converter based on a loop matrix according to claim 7, characterized in that, In step 7), for each branch-node relationship matrix in list f, the orientation of the switching transistor and diode is determined according to the following rules: ① A switching transistor that belongs to a specific branch or common branch of a circuit as the power supply, and whose direction is the same as that of the power supply; ② The currents in inductors L1 and L2 must remain in the same direction in both modes, while the currents in capacitor C1 must remain in opposite directions in both modes; ③ Avoid short-circuiting the power supply through the switching transistor or diode; The branch-node relationship matrix after determining the direction of the switching transistor and diode is still stored in list f.
9. The automatic construction method for a DC-DC converter based on a loop matrix according to claim 8, characterized in that, In step 8), for each branch-node relationship matrix in list f, the diode is disconnected to obtain the equivalent circuit of mode 1. The potential of the nodes at both ends of the diode is calculated. If there is a positive potential difference, the diode and the switch are turned on simultaneously in mode 1. The branch-node relationship matrix corresponding to this circuit is then eliminated. Finally, the branch-node relationship matrix that was not filtered out is output, and the corresponding DC-DC converter is constructed, that is, the DC-DC converter that can work normally and corresponds to the given loop matrix.