An insulator relay-type wireless power supply system and its coil parameter optimization method

Abstract

The present invention discloses a relay-type wireless power supply system for insulators and a method for optimizing coil parameters thereof. The system includes an insulator string, a transmitting coil, a relay coil, and a receiving coil. The insulator string includes a plurality of insulator discs. The transmitting coil is embedded outside the first insulator disc, the receiving coil is embedded outside the last insulator disc, and the relay coil is embedded outside the insulator discs in the middle part; The method includes: determining the coil diameter according to the diameter of the insulator disc and the firmness of the embedded coil; selecting the number of coil turns and the wire diameter according to the external insulation characteristics of the insulator string itself and the requirements of the coil quality factor; taking the minimum power supply requirement of the on-line monitoring equipment as the premise and the improvement of the transmission efficiency as the goal, optimizing the number of relay coils and the arrangement position of the coils. The present invention significantly improves the transmission power and transmission efficiency of the system, realizes the stable operation of the monitoring equipment of the transmission tower, is simple, effective and easy to implement, and has good economy and practicability.

Description

Technical Field

[0001] The present invention relates to the wireless power supply technology for transmission tower monitoring equipment, and particularly to an insulator relay type wireless power supply system and a method for optimizing coil parameters thereof. Background Art

[0002] With the continuous development of smart grids, online monitoring equipment for transmission towers will be fully covered in the future, and the power supply reliability of online monitoring equipment has become an important factor restricting the development of online monitoring technology for transmission towers. At present, the power supply methods for transmission tower monitoring equipment mainly include solar power supply, microwave power supply, voltage mutual induction type, and battery power supply, etc., but there are problems such as insufficient reliability and high implementation difficulty in terms of safety, practicability, and application cost. In recent years, the power supply method combining an energy harvester with wireless power transmission technology provides a new power supply solution for transmission tower monitoring equipment. An electric current transformer is installed on a high-voltage transmission line, and the energy obtained from the line is used to power the monitoring equipment installed on the transmission line tower through wireless power transmission technology, ensuring the safe and stable operation of the transmission line.

[0003] Existing research on wireless power supply for transmission towers mainly focuses on aspects such as improving the power extraction efficiency of CT, and relatively few studies have been conducted on the problem of long-distance, high-efficiency, and stable transmission of the energy obtained from the transmission line to the monitoring equipment. Some studies have shown that the addition of relay coils can not only increase the transmission distance of the wireless power supply system but also further improve the energy transmission efficiency, but the influence of coil parameters such as the arrangement position and number of turns of the coils on the transmission performance of the system has not been analyzed in detail. Summary of the Invention

[0004] Object of the Invention: Aiming at the power supply problem of existing online monitoring equipment for transmission towers, one object of the present invention is to provide an insulator relay type wireless power supply system.

[0005] Another object of the present invention is to provide a method for optimizing coil parameters of an insulator relay type wireless power supply system, which can greatly improve the transmission power and transmission efficiency of the wireless power supply system, providing a reliable guarantee for the continuous and stable operation of the monitoring equipment.

[0006] Technical Solution: An insulator relay type wireless power supply system of the present invention includes: an insulator string, a transmitting coil, a relay coil, and a receiving coil. The insulator string includes a plurality of insulator discs. The transmitting coil is externally embedded on the first insulator disc, the receiving coil is externally embedded on the last insulator disc, and the relay coil is externally embedded on the insulator discs in the middle part.

[0007] Preferably, the shapes of the transmitting coil, the relay coil, and the receiving coil are spatial spiral structures, and each coil has the same size parameters.

[0008] Preferably, there are multiple relay coils, and the number n of relay coils does not exceed the number of insulator discs in the middle part.

[0009] A method for optimizing coil parameters of an insulator relay-type wireless power supply system according to the present invention includes the following steps:

[0010] S1. Determine the coil diameter D according to the diameter of the insulator disc and the firmness of the externally embedded coil. The coil includes a transmitting coil, a relay coil, and a receiving coil, and each coil has the same size parameters;

[0011] S2. Select the number of coil turns N and the wire diameter a according to the external insulation characteristics of the insulator string and the requirement of the coil quality factor Q;

[0012] S3. Optimize the number n of relay coils and the arrangement position of the coils on the premise of meeting the minimum power supply requirement P of the on-line monitoring device Lmin and with the goal of improving the transmission efficiency.

[0013] Further, the selection range of the coil diameter D in step S1 is:

[0014] D 0 ≤ D ≤ D max

[0015] where D 0 is the diameter of the insulator disc, and D max is the maximum coil diameter that does not affect the firmness of the externally embedded coil.

[0016] Further, the coil quality factor Q in step S2 is:

[0017]

[0018] where ω is the working angular frequency, L is the self-inductance of the coil, R is the internal resistance of the coil, f is the working frequency, μ 0 is the vacuum coefficient, a is the wire diameter, and σ is the conductivity. Within the limit range of the insulator disc thickness T, Na ≤ T, and the coil quality factor Q is as large as possible.

[0019] Further, the optimization method for the number n of relay coils and the arrangement position of the coils in step S3 is:

[0020] Model the insulator relay-type wireless power supply system, and write the KVL equation through the equivalent circuit of the insulator relay-type wireless power supply system;

[0021] Solve the KVL equation to obtain the loop current of each coil, and further solve to obtain the specific expressions of the system transmission power and transmission efficiency and the parameters of each coil;

[0022] According to the limit conditions of the coil arrangement position, on the premise of meeting the minimum power supply requirement P of the on-line monitoring deviceLmin On the premise of [specific premise], with the goal of improving the transmission efficiency, the number of relay coils \(n\) and the arrangement positions of the coils are optimized.

[0023] Furthermore, the KVL equation is:

[0024]

[0025] Wherein, is the high-frequency inverter voltage source, \(\omega\) is the operating angular frequency, \(R\) L is the equivalent load, \(L\) s , \(C\) s , \(R\) s are respectively the self-inductance, compensation capacitance and equivalent internal resistance of the transmitting coil, \(L\) r , \(C\) r , \(R\) r are respectively the self-inductance, compensation capacitance and equivalent internal resistance of the receiving coil, \(L\) i , \(C\) i , \(R\) i (\(i\in1,2,\cdots,n\)) are respectively the self-inductance, compensation capacitance and equivalent internal resistance of relay coil \(i\). is the current at the transmitting end, is the current flowing through the load \(R\) L , is the current flowing through each relay coil \(i\). \(M\) si is the mutual inductance between the transmitting coil and relay coil \(i\), \(M\) ir is the mutual inductance between relay coil \(i\) and the receiving coil, \(M\) ij (\(i\neq j\)) is the mutual inductance between relay coils \(i\) and \(j\), \(M\) sr is the mutual inductance between the transmitting coil and the receiving coil.

[0026] Furthermore, the relationship between the system transmission power \(P\) L and the transmission efficiency \(\eta\) with the number of relay coils \(n\) and the coil arrangement positions is expressed as:

[0027]

[0028] Wherein, \(d\) si is the distance between the transmitting coil and relay coil \(i\), \(i\in1,2,\cdots,n\); \(d\) ir is the distance between relay coil \(i\) and the receiving coil, \(d\) ij is the distance between relay coils \(i\) and \(j\), \(j\in1,2,\cdots,n\), \(i\neq j\); \(d\) sr is the distance between the transmitting coil and the receiving coil.

[0029] There are the following restrictions on the coil arrangement positions:

[0030]

[0031] Among them, l is the insulator disc distance between adjacent positions of the externally embeddable coils, n 0 is the number of insulator discs, m is the number of insulator discs for the externally embeddable relay coils, d sr is the distance between the transmitting coil and the receiving coil, k = 1, 2, 3, ….

[0032] Furthermore, the method for optimizing the coil arrangement when the number of relay coils is n is as follows:

[0033] The externally embeddable positions of the relay coils on the insulator string are respectively marked as ①, ②, …, m, and the positions of the insulator string pointed to by J 1 , J 2 , …, J n respectively represent the externally embeddable positions of relay coils 1, 2, …, n, where n ≤ m.

[0034] When the number of relay coils is n, initialize k 1 = 1, P L = 0, η = 0. Then execute the following steps:

[0035] (1) If k 1 ≤ m - n + 1, then J 1 → k 1 , k 2 = k 1 + 1, execute the next step, otherwise end;

[0036] (2) If k 2 ≤ m - n + 2, then J 2 → k 2 , k 3 = k 2 + 1, execute the next step, otherwise k 1 = k 1 + 1, return to the previous step;

[0037] ……

[0038] ……

[0039] (n - 1) If k n-1 ≤ m - 1, then J n-1 → k n-1 , k n = k n-1 + 1, execute the next step, otherwise k n-2 = k n-2 + 1, return to the previous step;

[0040] (n) If k n ≤ m, then J n → k n , and use the system transmission power P LCalculate J at this time according to the relational expressions of the transmission efficiency η with the number n of relay coils and the arrangement positions of the coils 1 , J 2 , …, J n-1 , J n When J points to the externally embedded position of the relay coil outside the insulator string, the corresponding P L , η, are denoted as the scheme {J 1 →k 1 , J 2 →k 2 , …, J n-1 →k n-1 , J n →k n}. Compare the performances of different schemes, and save the coil position arrangement method with P L >P Lmin and the optimal efficiency. k n =k n +1, continue to execute step (n), otherwise k n-1 =k n-1 +1, and return to the previous step.

[0041] Among them, the values of k 1 , k 2 , …, k n-1 , k n represent the serial numbers of the externally embedded positions of the relay coils marked on the insulator string. Through the above steps, until k 1 >m - n + 1, compare the performances of all coil arrangement schemes when the number of relay coils is n, and obtain the coil position arrangement method that satisfies P L >P Lmin and has the optimal efficiency.

[0042] Adopt the above method to obtain the corresponding optimal coil arrangement methods when the number of relay coils n is 1, 2, …, m respectively. Finally, compare the performances of each scheme to determine the optimal number n of relay coils and the coil arrangement positions.

[0043] Advantageous effects: Compared with the prior art, the advantages of the present invention are as follows: (1) Using the insulator string as the carrier for externally embedding the relay coil, the energy obtained by line induction is transmitted over a long distance to the low-voltage side of the tower to supply power to the monitoring equipment; (2) By optimizing the number n of relay coils and the arrangement positions, the transmission distance and transmission efficiency of the wireless power supply system are significantly improved, so that the system meets the power supply requirements of the monitoring equipment; (3) The power supply method is not affected by the external environment, can supply power to the monitoring equipment stably and reliably, reduces the failure rate of transmission towers, and has good social and economic benefits. Description of the Drawings

[0044] Figure 1 is the structural diagram of the insulator string model with externally embedded coils;

[0045] Figure 2 It is a structural diagram of a single insulator disc;

[0046] Figure 3 It is an equivalent circuit diagram of a relay-type wireless power supply system;

[0047] Figure 4 It is a flow chart for optimizing the coil parameters of a relay-type wireless power supply system;

[0048] Figure 5 It is a flow chart for optimizing the number n of relay coils and the arrangement positions of the coils;

[0049] Figure 6 It is a structural diagram of an insulator string model including 8 insulator discs in the embodiment;

[0050] Figure 7 It is a flow chart for optimizing the number n of relay coils and the arrangement positions of the coils of an insulator string model including 8 insulator discs. Detailed implementation manners

[0051] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The following are only the preferred implementation manners of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can still be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

[0052] As Figure 1 shown, an insulator relay-type wireless power supply system of the present invention includes: an insulator string, a transmitting coil, a relay coil, and a receiving coil. The insulator string is used as a channel for wireless energy transmission between a high-voltage power-taking device and an on-line monitoring device. The insulator string is used as a coil carrier, and the coil is embedded outside the insulator string. The structure of a single insulator disc is as Figure 2 shown therein, where D 0 is the diameter of the large insulator disc, T is the thickness of the insulator disc. Considering that the coil diameter should be as large as possible, the coil is embedded outside the large-diameter insulator disc. The insulator discs can be connected in series into an insulator string through fittings, as Figure 1 shown, l is the distance between two adjacent large-diameter insulator discs, and d sr is the distance between the transmitting coil and the receiving coil. The insulator string includes a plurality of insulator discs. The transmitting coil is embedded outside the first insulator disc, the receiving coil is embedded outside the last insulator disc, and the relay coil is embedded outside the insulator discs in the middle part; the shapes of the coils are all spatial spiral structures, and the coils have the same size parameters; there are a plurality of relay coils, and the number n of relay coils does not exceed the number m of the insulator discs in the middle part. The insulator string is composed of n 0 identical insulator discs connected in series, and the positions where the relay coils can be embedded outside the insulator string are respectively marked as ①, ②, …, m.

[0053] Theoretical modeling is carried out on the relay - type wireless power supply system for insulators, and the equivalent circuit diagram of the relay - type wireless power supply system is obtained. As Figure 3 shown, is the high - frequency inverter voltage source, and R L is the equivalent load of the monitoring device. L s , C s , R s are respectively the self - inductance, compensation capacitance and equivalent internal resistance of the transmitting coil. L r , C r , R r are respectively the self - inductance, compensation capacitance and equivalent internal resistance of the receiving coil. L i , C i , R i (i ∈ 1, 2, …, n) are respectively the self - inductance, compensation capacitance and equivalent internal resistance of the relay coil i, and n is the number of relay coils. The transmitting coil, multiple relay coils and receiving coil have the same size parameters, and the equivalent internal resistance and self - inductance of each coil can be regarded as equal. Each coil is connected in series with a compensation capacitor so that each loop has the same resonance frequency. is the current at the transmitting end, is the current flowing through the load R L , is the current flowing through each relay coil i. M si is the mutual inductance between the transmitting coil and the relay coil i, M ir is the mutual inductance between the relay coil i and the receiving coil, and M ij (i ≠ j) is the mutual inductance between the relay coils i and j. By changing the relative position between the coils, the mutual inductance between the coils can be changed, and then the loop current of each coil can be changed. Therefore, the coil arrangement position can be optimized to improve the system transmission power and transmission efficiency.

[0054] As Figure 4 shown, the specific steps of the coil parameter optimization method are as follows:

[0055] (1) According to the diameter of the insulator disc and the firmness of the externally - embedded coil, determine the coil diameter D. The coil includes a transmitting coil, relay coils and a receiving coil, and each coil has the same size parameters;

[0056] The coil is externally - embedded on the insulator string. The coil diameter D should not be less than the diameter of the insulator disc. At the same time, considering the firmness of the externally - embedded coil, the coil diameter D should not be too large and can be reasonably selected according to the actual firmness of the coil nesting. The coil diameter is limited within the target range:

[0057] D 0 ≤ D ≤ D max (1 - 1)

[0058] Among them, D 0 is the insulator disc diameter, and D max is the maximum coil diameter that does not affect the firmness of the external embedding of the coil.

[0059] (2) According to the requirements of the external insulation characteristics of the insulator string itself and the quality factor Q of the coil, select the number of turns N of the coil and the wire diameter a;

[0060] An important parameter in coil design is the quality factor Q. The larger the Q value, the smaller the coil loss. For a hollow spiral coil, the coil quality factor Q is:

[0061]

[0062] Among them, L is the self-inductance of the coil, R is the internal resistance of the coil, f is the operating frequency, μ 0 is the vacuum coefficient, a is the wire diameter, and σ is the conductivity. It can be seen from Equation (1-2) that the number of turns N of the coil and the wire diameter a are proportional to the Q value. The larger the number of turns N of the coil and the wire diameter a, the larger the Q value. However, when the coil is externally embedded on the insulator disc, if the number of turns of the coil is wound too much, it will affect the external insulation characteristics of the insulator string itself and damage its insulation performance. Therefore, there are limitations on the number of turns N of the coil and the wire diameter a, and Na ≤ T, where T is the thickness of the insulator disc. The selection principle of the number of turns N of the coil and the wire diameter a is to make the Q value as large as possible within the limit range.

[0063] (3) On the premise of meeting the minimum power supply requirement P of the on-line monitoring device Lmin and with the goal of improving the transmission efficiency, optimize the number n of relay coils and the coil arrangement position;

[0064] Conduct theoretical modeling on the relay wireless power supply system, and write the KVL equation through the equivalent circuit of the relay wireless power supply system:

[0065]

[0066] Among them, is the high-frequency inverter voltage source, and R L is the equivalent load of the monitoring device, and L s , C s , R s are the self-inductance, compensation capacitance and equivalent internal resistance of the transmitting coil respectively, and L r , C r , R r are the self-inductance, compensation capacitance and equivalent internal resistance of the receiving coil respectively, and L i , C i , R i (i ∈ 1, 2, …, n) are the self-inductance, compensation capacitance and equivalent internal resistance of the relay coil i respectively. is the current at the transmitting end, is the current flowing through the load RL The current is the current flowing through each relay coil i. M si is the mutual inductance between the transmitting coil and relay coil i, M ir is the mutual inductance between relay coil i and the receiving coil, M ij (i≠j) is the mutual inductance between relay coils i and j, M sr is the mutual inductance between the transmitting coil and the receiving coil.

[0067] Solving the KVL equation gives the loop currents of each coil, and further solving yields the specific expressions of the system transmission power and transmission efficiency in terms of each coil parameter. For systems with different numbers n of relay coils and coil arrangement positions, with other system parameters determined, the system transmission power P L and transmission efficiency η as functions of the number n of relay coils and coil arrangement positions can be expressed as:

[0068]

[0069] where d si is the distance between the transmitting coil and relay coil i (i ∈ 1, 2, …, n), d ir is the distance between relay coil i and the receiving coil, d ij (i≠j) is the distance between relay coils i and j, d sr is the distance between the transmitting coil and the receiving coil. From Equation (1-4), it can be seen that when other system parameters are determined, the system transmission power and efficiency are only affected by the coil arrangement positions and the number of relay coils, and any change in the position of any relay coil will change the system performance. Therefore, it is necessary to analyze and optimize it.

[0070] The coils are embedded outside the insulator discs. Therefore, the number n of relay coils should not exceed the number of insulator discs in the middle part. At the same time, the coil positions cannot be arranged randomly. The coils need to be embedded outside the insulator discs, and there are the following restrictions on the coil arrangement positions:

[0071]

[0072] where l is the distance between insulator discs at adjacent positions where coils can be embedded outside, m is the number of insulator discs where relay coils can be embedded outside, n 0 is the number of insulator discs, d sr is the distance between the transmitting coil and the receiving coil, k = 1, 2, 3, …. To meet the minimum power supply requirement P Lmin of the on-line monitoring device as a precondition and with the goal of improving the transmission efficiency, the number n of relay coils and the coil arrangement positions are optimized.

[0073] The positions where relay coils can be embedded outside on the insulator string are respectively marked as ①, ②, …, m, and are denoted by J1 , J 2 , …, J n The positions of the insulator strings pointed to by J represent the embedded positions of the relay coils 1, 2, …, n (n ≤ m) respectively. For example Figure 5 is the flow chart for optimizing the coil arrangement when the number of relay coils is n. Initialize k 1 = 1, P L = 0, η = 0. Then perform the following steps:

[0074] (1) If k 1 ≤ m - n + 1, then J 1 → k 1 , k 2 = k 1 + 1, perform the next step, otherwise end;

[0075] (2) If k 2 ≤ m - n + 2, then J 2 → k 2 , k 3 = k 2 + 1, perform the next step, otherwise k 1 = k 1 + 1, return to the previous step;

[0076] ……

[0077] ……

[0078] (n - 1) If k n-1 ≤ m - 1, then J n-1 → k n-1 , k n = k n-1 + 1, perform the next step, otherwise k n-2 = k n-2 + 1, return to the previous step;

[0079] (n) If k n ≤ m, then J n → k n , calculate P at this time using formula (1 - 4), 1 , J 2 , …, J n-1 , J n pointing to the corresponding P when the relay coil of the insulator string is at the embedded position, L η, denoted as the scheme {J 1 → k 1 , J 2 → k 2 , …, J n-1 → k n-1 , J n → k n}, compare the performance of different schemes, and save PL > P Lmin and the most efficient coil position arrangement, k n = k n + 1, continue to execute step (n), otherwise k n-1 = k n-1 + 1, return to the previous step.

[0080] where k 1 , k 2 , …, k n-1 , k n values represent the serial numbers of the embeddable positions of the relay coils marked on the insulator string. Through the above steps, until k 1 > m - n + 1, compare the performance of all coil arrangement schemes when the number of relay coils is n, and obtain the coil position arrangement that satisfies P L > P Lmin and is the most efficient.

[0081] Adopt the above method to obtain the corresponding best coil arrangements when the number of relay coils n is 1, 2, …, m respectively. Finally, compare the performance of each scheme to determine the best number of relay coils n and the coil arrangement positions. Through the above steps, the coil parameters of the wireless power supply system for the insulator relay type transmission tower are finally determined, greatly improving the system transmission power and transmission efficiency.

[0082] The following takes an insulator string composed of 8 series-connected insulator discs as an example for illustration. As Figure 6 shown, the embeddable positions of the relay coils on the insulator string are marked as ①, ②, ③, ④, ⑤, and ⑥ respectively. Use J 1 , J 2 , …, J n to point to the positions of the insulator string, which respectively represent the embeddable positions of relay coils 1, 2, …, n (n ≤ 6). As Figure 7 shown, it is the flow chart for optimizing the coil arrangement when the number of relay coils is n. Initialize k 1 = 1, P L = 0, η = 0. Then execute the following steps:

[0083] (1) If k 1 ≤ 6 - n + 1, then J 1 → k 1 , k 2 = k 1 + 1, execute the next step, otherwise end;

[0084] (2) If k 2 ≤ 6 - n + 2, then J 2 → k 2 , k 3 = k 2+1, perform the next step, otherwise k 1 = k 1 +1, return to the previous step;

[0085] ……

[0086] ……

[0087] (n - 1) If k n-1 ≤5, then J n-1 →k n-1 , k n = k n-1 +1, perform the next step, otherwise k n-2 = k n-2 +1, return to the previous step;

[0088] (n) If k n ≤6, then J n →k n , calculate J at this time using Equation (1 - 4) 1 , J 2 , …, J n-1 , J n points to the P corresponding to the position where the relay coil is externally embedded in the insulator string L , η, denoted as the scheme {J 1 →k 1 , J 2 →k 2 , …, J n-1 →k n-1 , J n →k n}, compare the performance of different schemes, and save the P L > P Lmin and the coil position arrangement with the optimal efficiency, k n = k n +1, continue to execute step (n), otherwise k n-1 = k n-1 +1, return to the previous step.

[0089] Among them, the values of k 1 , k 2 , …, k n-1 , k n represent the serial numbers of the positions where the relay coils marked on the insulator string can be externally embedded. Through the above steps, until k 1 > 6 - n + 1, compare the performance of all coil arrangement schemes when the number of relay coils is n, and obtain the coil position arrangement that satisfies P L > P Lmin and has the optimal efficiency.

[0090] Adopt the above method to obtain the corresponding optimal coil arrangement modes when the number n of relay coils is 1, 2, …, 6 respectively one by one. Finally, compare the performances of each scheme to determine the optimal number n of relay coils and the coil arrangement positions.

Claims

1. An optimization method for coil parameters of an insulator relay - type wireless power supply system, characterized in that, it includes the following steps: S1. Determine the coil diameter D according to the diameter of the insulator disc and the firmness of the externally - embedded coil. The coil includes a transmitting coil, a relay coil, and a receiving coil, and each coil has the same size parameters; S2. Select the number of coil turns N and the wire diameter a according to the external insulation characteristics of the insulator string itself and the requirement of the coil quality factor Q. The coil quality factor Q is: where ω is the working angular frequency, L is the self-inductance of the coil, R is the internal resistance of the coil, f is the working frequency, μ 0 is the vacuum coefficient, a is the wire diameter, and σ is the conductivity; S3. On the premise of meeting the minimum power supply requirement P of the on-line monitoring device, with the goal of improving the transmission efficiency, optimize the number n of relay coils and the coil arrangement positions. The method is as follows: Lmin Premise, aiming at improving the transmission efficiency, optimize the number n of relay coils and the coil arrangement positions. The method is as follows: Model the insulator relay - type wireless power supply system, and write the KVL equation through the equivalent circuit of the insulator relay - type wireless power supply system: Among them, is a high-frequency inverter voltage source, ω is the working angular frequency, and R L is the equivalent load, L s , C s , R s are the self-inductance, compensation capacitor, and equivalent internal resistance of the transmitting coil respectively, L r , C r , R r are the self-inductance, compensation capacitor, and equivalent internal resistance of the receiving coil respectively, L i , C i , R i are the self-inductance, compensation capacitor, and equivalent internal resistance of relay coil i respectively, i ∈ 1, 2, …, n; is the current at the transmitting end, is the current flowing through the load R L , is the current flowing through each relay coil i; M si is the mutual inductance between the transmitting coil and relay coil i, M ir is the mutual inductance between relay coil i and the receiving coil, M ij is the mutual inductance between relay coils i and j, i ≠ j, M sr is the mutual inductance between the transmitting coil and the receiving coil; Solve the KVL equation to obtain the loop currents of each coil, and further solve to obtain the specific expressions of the system transmission power and transmission efficiency in terms of each coil parameter; Based on the limiting conditions of the coil arrangement position to meet the minimum power supply requirement P of the on-line monitoring device Lmin as a prerequisite, with the goal of improving the transmission efficiency, the number n of relay coils and the coil arrangement position are optimized.

2. The optimization method for coil parameters of an insulator relay - type wireless power supply system according to claim 1, characterized in that, the selection range of the coil diameter D in step S1 is: D 0 ≤D≤D max Among them, D 0 is the insulator disc diameter, and D max is the maximum coil diameter that does not affect the firmness of the external embedding of the coil.

3. The optimization method for coil parameters of an insulator relay - type wireless power supply system according to claim 1, characterized in that, System transmission power P L The relationships between the transmission efficiency η and the number n of relay coils and the coil arrangement positions are expressed as follows: where d si is the distance between the transmitting coil and relay coil i, i ∈ 1, 2, …, n; d ir is the distance between relay coil i and the receiving coil, d ij is the distance between relay coils i and j, j ∈ 1, 2, …, n, i ≠ j; d sr is the distance between the transmitting coil and the receiving coil; there are the following restrictions on the coil arrangement position: where l is the distance between insulator discs at adjacent positions where externally-embeddable coils can be located, n 0 is the number of insulator discs, m is the number of insulator discs for externally-embeddable relay coils, and k = 1, 2, 3, ….

4. The optimization method for coil parameters of an insulator relay - type wireless power supply system according to claim 1, characterized in that, the optimization method for the coil arrangement when the number of relay coils is n is: The externally embeddable positions of the relay coils on the insulator string are respectively marked as ①, ②, …, m, and use J 1 , J 2 , …, J n The positions of the insulator string pointed to respectively represent the externally embeddable positions of relay coils 1, 2, …, n, where n ≤ m; When the number of relay coils is n, initialize k 1 = 1, P L = 0, η = 0; then perform the following steps: (1) If k 1 ≤ m - n + 1, then J 1 → k 1 , k 2 = k 1 + 1, proceed to the next step, otherwise end; (2) If k 2 ≤ m - n + 2, then J 2 → k 2 ,k 3 = k 2 + 1, perform the next step, otherwise k 1 = k 1 + 1, return to the previous step; …… …… (n - 1) If k n-1 ≤ m - 1, then J n-1 → k n-1 ,k n = k n-1 + 1, execute the next step, otherwise k n-2 = k n-2 + 1, return to the previous step; (n) If k n ≤m, then J n →k n , calculate J at this time using the relational expressions of the system transmission power and transmission efficiency with the number of relay coils and the coil arrangement positions 1 , J 2 , …, J n-1 , J n corresponding to the system transmission power P L , transmission efficiency η when pointing to the externally embedded position of the relay coil of the insulator string, denoted as the scheme {J 1 →k 1 , J 2 →k 2 , …, J n-1 →k n-1 , J n →k n}, compare the performances of different schemes, save the coil position arrangement method with P L >P Lmin and the optimal efficiency, k n =k n +1, continue to execute step (n), otherwise k n-1 =k n-1 +1, return to the previous step; where k 1 , k 2 , …, k n-1 , k n represents the serial number of the embeddable position of the relay coil marked on the insulator string; through the above steps, until k 1 > m - n + 1, compare the performance of all coil arrangement schemes when the number of relay coils is n, and obtain the coil position arrangement method that satisfies P L > P Lmin and has the optimal efficiency; Adopt the above method to obtain the corresponding optimal coil arrangement when the number of relay coils n is 1, 2, …, m one by one. Finally, compare the performances of each scheme to determine the optimal number of relay coils n and the coil arrangement position.

5. The optimization method for coil parameters of an insulator relay - type wireless power supply system according to claim 1, characterized in that, the insulator relay - type wireless power supply system includes: an insulator string, a transmitting coil, a relay coil, and a receiving coil. The insulator string includes multiple insulator discs. The transmitting coil is externally - embedded on the first insulator disc, the receiving coil is externally - embedded on the last insulator disc, and the relay coil is externally - embedded on the insulator discs in the middle part.

6. The optimization method for coil parameters of an insulator relay - type wireless power supply system according to claim 5, characterized in that, the shapes of the transmitting coil, the relay coil, and the receiving coil are spatial spiral structures, and each coil has the same size parameters.

7. The optimization method for coil parameters of an insulator relay - type wireless power supply system according to claim 5, characterized in that, there are multiple relay coils, and the number of relay coils n does not exceed the number of insulator discs in the middle part.

Images