A multi-relay wireless power supply system modeling method

Abstract

The application relates to the technical field of wireless power supply, in particular to a multi-relay wireless power supply system modeling method, which comprises the following steps: S1, constructing a circuit equation based on an impedance matrix according to the circuit topology of the multi-relay wireless power supply system, and performing LDU decomposition on the impedance matrix of the system to obtain a lower triangular impedance matrix, a diagonal impedance matrix and an upper triangular impedance matrix; S2, performing forward voltage transformation according to the lower triangular impedance matrix and a system input voltage phasor; S3, solving forward current according to the diagonal impedance matrix and the forward voltage; S4, performing backward current transformation according to the upper triangular impedance matrix and the forward current to solve loop currents of the multiple relay coils. The method can clearly describe the cross-coupling relationship between the coils of the multi-relay wireless power supply system, can decompose the coil composition of each loop, and can be used for analyzing the input, output and other characteristics of the multi-relay wireless power supply system under complex cross-coupling.

Description

Technical Field

[0001] This invention relates to the field of wireless power supply technology, and in particular to a modeling method for a multi-relay wireless power supply system. Background Technology

[0002] Wireless power supply systems utilize the principle of near-field coupling in high-frequency electromagnetic fields, using a high-frequency magnetic field as the transmission medium. Electrical energy is wirelessly transmitted through magnetic field coupling between the transmitting and receiving coils. A common two-coil wireless power supply system consists of two parts: a transmitter connected to the power supply side and a receiver located on the load side. Energy is transferred from the transmitter to the receiver via electromagnetic induction. Wireless power supply systems feature electrical and mechanical isolation, making them suitable for harsh working environments such as high-voltage and dust-free environments.

[0003] To improve the transmission distance of a wireless power supply system while maintaining electrical isolation between coils, multiple relay coils can be inserted between the transmitting and receiving coils, forming a multi-relay wireless power supply system. Energy is primarily transferred from the first transmitting coil, gradually through the relay coils, to the receiving coil and the load. This multi-relay wireless power supply method can be used in high-voltage scenarios, such as powering monitoring equipment on power transmission line towers.

[0004] However, the existence of varying degrees of cross-coupling between multiple relay coils makes the circuit characteristics of multi-relay wireless power supply systems more complex. At the same time, it makes the impedance model and its solution for multi-relay wireless power supply systems very complex, making it difficult to obtain analytical solutions for the loop currents of each coil, thus making it difficult to accurately model and analyze the complex characteristics of multi-relay wireless power supply systems. Summary of the Invention

[0005] In view of this, the present invention provides a modeling method for multi-relay wireless power supply systems, which solves the problems of existing models of multi-relay wireless power supply systems being complex, difficult to solve analytically, and difficult to analyze the effects of coil cross-coupling.

[0006] To achieve the aforementioned objective, the present invention proposes a modeling method for a multi-relay wireless power supply system, the specific steps of which are as follows:

[0007] A modeling method for a multi-relay wireless power supply system, the key of which includes the following steps:

[0008] S1: Construct circuit equations based on the impedance matrix according to the circuit topology of the multi-relay wireless power supply system, and perform LDU decomposition on the impedance matrix of the system to obtain a lower triangular impedance matrix, a diagonal impedance matrix and an upper triangular impedance matrix.

[0009] S2: Perform forward voltage transformation based on the lower triangular impedance matrix and the system input voltage phasor;

[0010] S3: Solve for the forward current based on the diagonal impedance matrix and the forward voltage;

[0011] S4: Based on the upper triangular impedance matrix and the forward current, perform backward current transformation to solve for the loop current of multiple relay coils.

[0012] Furthermore, the circuit equation based on the impedance matrix constructed in step S1 according to the circuit topology of the multi-relay wireless power supply system is as follows:

[0013] in: For the impedance matrix of a multi-relay wireless power supply system, The system input voltage vector, Let be the current vector of the multi-relay coil loop to be solved, and n be the number of coil loops in the multi-relay wireless power supply system.

[0014] Furthermore, according to:

[0015]

[0016] Perform LDU decomposition on the impedance matrix of the system, where Z L Z is the lower triangular impedance matrix. D Z is the diagonal impedance matrix. U T is an upper triangular impedance matrix. pq Let be the transfer coefficient between the p-th coil loop and the q-th coil loop, and its expression is: K pq Let be the transfer impedance between the p-th coil loop and the q-th coil loop, and its expression is: Z t,p Let be the total equivalent impedance of the p-th coil loop, and its expression is: Z pp Z is the self-impedance of the p-th coil loop. pq Z represents the mutual impedance between the p-th coil loop and the q-th coil loop. t,k It represents the total equivalent impedance of the k-th coil loop.

[0017] Furthermore, the forward voltage transformation step in step S2 is represented as: Z L V f =V, where V f Defined as a forward voltage vector, where each element of the forward voltage vector is the forward voltage in the corresponding equivalent coil loop, the forward voltage in the m-th coil loop is expressed as:

[0018] in T is the system input voltage. f,mis the forward propagation coefficient of the m-th coil loop.

[0019] Furthermore, the forward voltage transformation step in step S2 is represented as: Z L V f =V, where V f Defined as a forward voltage vector, where each element of the forward voltage vector is the forward voltage in the corresponding equivalent coil loop, the forward voltage in the m-th coil loop is expressed as:

[0020]

[0021] Optionally, the forward current solution process in step S3 follows Z D I f =V f Proceed, where: I f Let m be the forward current vector, where each element represents the forward current in the corresponding equivalent coil loop. The forward current in the m-th coil loop is expressed as:

[0022] Furthermore, the backward current transformation process in step S4 follows Z... U I = I f In the formula, I is the actual coil loop current vector to be solved, where each element is the actual current in the corresponding coil loop. The current in the m-th coil loop is expressed as: In the formula, For the backward current transferred from the k-th coil loop to the m-th coil loop, where k > m, its expression is:

[0023]

[0024] T b,mk is the current backward transmission coefficient.

[0025] Furthermore, The backward current transferred from the k-th coil loop to the m-th coil loop can be expressed in recursive form as follows: T mj Let be the transfer coefficient between the m-th coil loop and the j-th coil loop.

[0026] The significant effects of this invention are:

[0027] (1) The modeling method provided by the present invention can clearly describe the cross-coupling relationship between coils in a multi-relay wireless power supply system.

[0028] (2) The modeling method provided by this invention can be used to decompose the coil composition of each loop and to give specific analytical expressions quickly and easily.

[0029] (3) Using the modeling method provided by this invention, the input and output characteristics of a multi-relay wireless power supply system under complex cross-coupling can be quickly analyzed. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0031] Figure 1 This is a circuit diagram of a five-coil multi-relay wireless power supply system in a specific embodiment of the present invention.

[0032] Figure 2 This is a flowchart of the modeling method in a specific embodiment of the present invention.

[0033] Figure 3 This is a model structure diagram in a specific embodiment of the present invention.

[0034] Figure 4 This is the backward current transformation process in a specific embodiment of the present invention. Detailed Implementation

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0036] by Figure 1 Taking the 5-coil multi-relay wireless power supply system shown as an example, this embodiment provides a modeling method for a multi-relay wireless power supply system. The specific steps are as follows: Figure 2 As shown, it includes:

[0037] S1: Construct circuit equations based on the impedance matrix according to the circuit topology of the multi-relay wireless power supply system, and perform LDU decomposition on the impedance matrix of the system to obtain a lower triangular impedance matrix, a diagonal impedance matrix and an upper triangular impedance matrix.

[0038] The circuit equation for a five-coil multi-relay wireless power supply system can be expressed as:

[0039]

[0040] For the i-th coil loop, its self-impedance can be expressed as:

[0041] For the p-th and q-th coil loops, their mutual impedance can be expressed as: Z pq=jωM pq =jX pq ;

[0042] LDU decomposition of the impedance matrix yields the lower triangular impedance matrix Z. L Diagonal impedance matrix Z D Upper triangular impedance matrix Z U It can be represented as:

[0043]

[0044]

[0045]

[0046] Thus, we can obtain, Figure 3 The model shown is composed of...

[0047] Combination Figure 1 The circuit system topology shown is configured according to the circuit parameters in Table 1. Following the steps above, the lower triangular impedance matrix can be calculated as follows:

[0048] Table 1: Circuit Parameters

[0049]

[0050] Based on the circuit parameters in Table 1, the lower triangular impedance matrix can be calculated as follows:

[0051]

[0052] The diagonal impedance matrix is:

[0053]

[0054] The upper triangular impedance matrix is:

[0055]

[0056] S2: Based on the lower triangular impedance matrix and the system input voltage phasor, perform forward voltage transformation according to Z... L V f =V can be used to calculate the forward voltage as:

[0057]

[0058] S3: Solve for the forward current based on the diagonal impedance matrix and the forward voltage;

[0059] Based on the forward voltage and diagonal impedance matrix, and The forward current can be calculated as follows:

[0060]

[0061] S4: Based on the upper triangular impedance matrix and the forward current, perform a backward current transformation to solve for the loop current of multiple relay coils. Specifically:

[0062] After obtaining the forward current, according to The actual current in the coil can then be calculated. The calculation process for the backward current transformation is as follows: Figure 4 As shown. Figure 4 The composition of the current in each coil and its coupling relationship with other coils can be clearly described.

[0063] In summary, the multi-relay wireless power supply system modeling method provided by this invention can clearly describe the cross-coupling relationship between coils in the multi-relay wireless power supply system, decompose the coil composition of each loop, and can be used to analyze the input, output and other characteristics of multi-relay wireless power supply systems under complex cross-coupling.

[0064] Finally, it should be noted that 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 should be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A modeling method for a multi-relay wireless power supply system, characterized in that... Includes the following steps: S1: Construct circuit equations based on the impedance matrix according to the circuit topology of the multi-relay wireless power supply system, and perform LDU decomposition on the system's impedance matrix to obtain a lower triangular impedance matrix, a diagonal impedance matrix, and an upper triangular impedance matrix; specifically according to: Perform LDU decomposition on the impedance matrix of the system, where: For the impedance matrix of a multi-relay wireless power supply system, Z L Z is the lower triangular impedance matrix. D Z is the diagonal impedance matrix. U T is an upper triangular impedance matrix. pq Let be the transfer coefficient between the p-th coil loop and the q-th coil loop, and its expression is: K pq Let be the transfer impedance between the p-th coil loop and the q-th coil loop, and its expression is: Z t,p Let be the total equivalent impedance of the p-th coil loop, and its expression is: , Let be the self-impedance of the p-th coil loop. Let be the mutual impedance between the p-th coil loop and the q-th coil loop. The total equivalent impedance of the k-th coil loop; S2: Perform forward voltage transformation based on the lower triangular impedance matrix and the system input voltage phasor; S3: Solve for the forward current based on the diagonal impedance matrix and the forward voltage; S4: Based on the upper triangular impedance matrix and the forward current, perform backward current transformation to solve for the loop current of multiple relay coils.

2. The modeling method for a relay wireless power supply system according to claim 1, characterized in that: The circuit equation based on the impedance matrix constructed in step S1 according to the circuit topology of the multi-relay wireless power supply system is as follows: in: For the impedance matrix of a multi-relay wireless power supply system, The system input voltage vector, Let be the current vector of the multi-relay coil loop to be solved, and n be the number of coil loops in the multi-relay wireless power supply system.

3. The modeling method for a relay wireless power supply system according to claim 2, characterized in that: The forward voltage transformation step in step S2 is represented as follows: V f Defined as a forward voltage vector, where each element of the forward voltage vector is the forward voltage in the corresponding equivalent coil loop, the forward voltage in the m-th coil loop is expressed as: ,in The system input voltage, is the forward propagation coefficient of the m-th coil loop.

4. The modeling method for a relay wireless power supply system according to claim 2, characterized in that: The forward voltage transformation step in step S2 is represented as follows: V f Defined as a forward voltage vector, where each element of the forward voltage vector is the forward voltage in the corresponding equivalent coil loop, the forward voltage in the m-th coil loop is expressed as: 。 5. The modeling method for a relay wireless power supply system according to claim 3 or 4, characterized in that: The forward current solution process in step S3 follows the steps outlined below. Proceed, where: I f Let m be the forward current vector, where each element represents the forward current in the corresponding equivalent coil loop. The forward current in the m-th coil loop is expressed as: .

6. The modeling method for a relay wireless power supply system according to claim 5, characterized in that: The backward current transformation process in step S4 follows In the formula, I is the actual coil loop current vector to be solved, where each element is the actual current in the corresponding coil loop. The current in the m-th coil loop is expressed as: In the formula, For the backward current transferred from the k-th coil loop to the m-th coil loop, where k > m, its expression is: , is the current backward transmission coefficient.

7. The modeling method for a relay wireless power supply system according to claim 6, characterized in that: The backward current transferred from the k-th coil loop to the m-th coil loop can be expressed in recursive form as follows: , Let be the transfer coefficient between the m-th coil loop and the j-th coil loop.

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