Wide-current high-power energy taking device for power transmission line and control method thereof

Abstract

The invention discloses a power transmission line wide-current high-power energy taking device and a control method thereof.The energy taking device comprises a damping magnetic core branch, an energy taking magnetic core branch and an impedance regulation and control branch, and the damping magnetic core branch comprises an open-air-gap damping magnetic core T1 wound with a first secondary winding; the energy-taking magnetic core branch comprises a closed energy-taking magnetic core T2, a rectifying circuit and a load, a second secondary winding and a third winding are wound on the T2, and a primary winding formed by parallel leads is inserted into a central hole of the T2; the two ends of the primary winding are connected to the two ends of a power transmission line sleeved with the air gap damping magnetic core T1 through a clamp or a connecting terminal so as to connect the outer rings of the damping magnetic core branch and the energy taking magnetic core branch, and the impedance regulation and control branch comprises an impedance regulation module and two relay switches K1 and K2. The invention aims to realize wide-current high-power energy taking of the power transmission line according to the characteristic that the current of the power transmission line fluctuates in a wide range, and can realize dynamic adjustment of output power and match load power requirements.

Description

Technical Field

[0001] The present invention relates to a power supply technology for online equipment of a high-voltage transmission line, and in particular to a transmission line wide-current and high-power energy taking device and a control method thereof. Background Art

[0002] As the power grid becomes smarter, a large number of online devices for power transmission lines, such as monitoring sensors, drones, and inspection robots, have been promoted and applied. Considering the special geographical environment of high-altitude lines, the power supply problem is still the key to restricting the development of various types of online devices. At present, the main power supply methods for online devices include battery power supply, new energy power supply, laser power supply, electric field power supply, and magnetic core induction power supply. Among these methods, the magnetic core induction power supply method has the advantages of simple structure, easy installation, large power, direct energy supply at high potential, and low cost, and has become the most effective online equipment power supply method. However, the conventional magnetic core induction energy harvesting method still has the following shortcomings: 1. Due to installation reasons, the energy harvesting magnetic core must have an air gap, which causes the effective magnetic permeability of the magnetic core to drop significantly, about 1 / 8 to 1 / 5 of the magnetic core without an air gap, and it is impossible to transfer enough line energy to the load; 2. Considering that the line current fluctuates in a wide range, the energy harvesting circuit cannot dynamically adjust the output to match the load power demand; 3. The contradiction between the small current lower limit and the core saturation problem is not resolved, and energy storage elements or discharge circuits are usually required to assist the work. In order to meet the requirements of both, the output power is mostly sacrificed. Therefore, how to achieve an energy harvesting method that is suitable for a wide current range of the line and has a high power output at the same time has become a key technical problem that needs to be solved urgently. Summary of the invention

[0003] Technical problem to be solved by the present invention: In view of the above-mentioned problems in the prior art, a transmission line wide current and high-power energy extraction device and a control method thereof are provided. The present invention aims to realize wide current and high-power energy extraction of transmission lines according to the characteristics of transmission line current fluctuations in a wide range, and can realize dynamic adjustment of output power and matching of load power requirements.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: A transmission line wide current high power energy acquisition device, comprising a damping core branch, an energy acquisition core branch and an impedance control branch, wherein the damping core branch comprises an open air gap damping core T1 for sleeved on the transmission line, the open air gap damping core T1 is wound with a first secondary winding, the energy acquisition core branch comprises a closed energy acquisition core T2, a rectifier circuit and a load, the closed energy acquisition core T2 is wound with a second secondary winding and a tertiary winding, the tertiary winding is sequentially connected to the rectifier circuit and the load, a primary winding composed of parallel wires is inserted in the central opening of the closed energy acquisition core T2, and both ends of the primary winding are connected by The clamps or connecting terminals are connected to the two ends of the transmission line to which the air-gap damping core T1 is sleeved to connect the outer ring of the damping core branch and the energy-taking core branch. The impedance control branch includes an impedance adjustment module and two relay switches K1 and K2. The impedance adjustment module and the relay switch K1 are connected in series and arranged on a loop formed by connecting the first secondary winding and the second secondary winding end to end. One end of the relay switch K2 is connected to the middle node between the impedance adjustment module and the relay switch K1, and the other end is connected to the wire between the first secondary winding and the second secondary winding to connect the inner ring of the damping core branch and the energy-taking core branch.

[0005] Optionally, the impedance adjustment module is composed of two reverse parallel controlled thyristors T1 and T2, two inductance elements L f and L c and a compensation capacitor C f The two reverse parallel controlled thyristors T1 and T2 and the inductor element L f After connecting in series, it is connected with the compensation capacitor C f The parallel branch is connected to form a parallel branch, and then the parallel branch and the inductor element L c Series connection.

[0006] Optionally, the closed energy-taking magnetic core T2 is designed with three windings, the number of turns of the primary winding formed by parallel wires is 1, and the number of turns of the second secondary winding is less than the number of turns of the tertiary winding.

[0007] Optionally, the rectifier circuit is a PWM rectifier circuit.

[0008] In addition, the present invention also provides a control method for the above-mentioned transmission line wide current high power energy extraction device, comprising the following steps of extracting energy from a transmission line whose line current is greater than a preset lower limit threshold value and less than a critical saturation current: A1) Close the relay switch K2 and open the relay switch K1; A2) Adjust the trigger angle of the controllable thyristors T1 and T2 in the impedance adjustment module so that the impedance of the impedance adjustment module presents a capacitive characteristic and forms a parallel resonance with the excitation impedance of the open air gap damping core T1. At this time, the impedance of the impedance adjustment module is: , , In the above formula, is the impedance of the impedance adjustment module, is the current angular frequency, The equivalent capacitance value of the parallel resonance formed by the impedance adjustment module and the excitation impedance of the air-gap damping core T1; is the number of turns of the first and second windings, is the magnetizing resistance of the air-gap damping core T1, is the magnetizing inductance of the air-gap damping core T1; A3) The number of turns of the tertiary winding is designed according to the load size so that the impedance of the load on the primary side of the closed energy-taking core T2 matches the impedance of the parallel resonance of the open air-gap damping core T1. At this time, the transmission line wide current and high power energy-taking device has the maximum power output.

[0009] Optionally, the calculation function expression of the maximum power in step A3) is: , In the above formula, is the maximum power, is the effective value of the line current of the transmission line, is the magnetizing resistance of the air-gap damping core T1, is the quality factor of the gapped damping core T1.

[0010] Optionally, the preset lower limit threshold is 20A, and the critical saturation current is 70A.

[0011] Optionally, the method further includes the following steps of extracting energy from a transmission line whose line current is less than a preset upper threshold value and greater than a critical saturation current: B1) Close the relay switch K1 and open the relay switch K2; B2) Adjust the trigger angle of the controllable thyristors T1 and T2 in the impedance adjustment module so that the impedance of the impedance adjustment module presents an inductive characteristic to quickly resist the saturation of the magnetic core, and at this time the impedance of the impedance adjustment module is: , In the above formula, is the impedance of the impedance adjustment module, is the current angular frequency, is the equivalent inductance of the impedance adjustment module; B3) The inductance of the impedance adjustment module is further adjusted by adjusting the trigger angle of the controllable thyristors T1 and T2 in the impedance adjustment module, so that the voltage across the closed energy-taking magnetic core T2 is less than the critical saturation voltage value of the magnetic core. At this time, the closed energy-taking magnetic core T2 operates in the non-saturation zone and the power output to the load by the wide current and high-power energy-taking device of the transmission line is adjustable.

[0012] Optionally, in step B3), the calculation function expression of the power output by the transmission line wide current high power energy taking device to the load is: , In the above formula, It is the power output from the wide current and high power energy taking device of the transmission line to the load. is the number of turns of the first and second windings, , are the turns of the second secondary winding and the third winding respectively, is the effective value of the line current of the transmission line, is the size of the load, , are the excitation resistance and excitation inductance of the air-gap damping core T1, is the equivalent inductance of the impedance adjustment module, is the current angular frequency.

[0013] Optionally, the preset upper limit threshold value is 1000A.

[0014] Compared with the prior art, the present invention mainly has the following advantages: the present invention can break through the limitations of installation conditions and achieve higher power output when the line current is small. When the line current is large, it can solve the problems of power attenuation and severe heat generation caused by the saturation characteristics of ferromagnetic materials. Considering the characteristics of transmission line current fluctuations in a wide range, the present invention can dynamically adjust the output power to match the load power demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the circuit topology structure of the device according to the embodiment of the present invention.

[0016] Figure 2 It is a schematic diagram of the circuit principle of the impedance adjustment module according to an embodiment of the present invention.

[0017] Figure 3 It is a schematic diagram of the circuit principle of the PWM rectifier circuit according to an embodiment of the present invention.

[0018] Figure 4 It is an equivalent circuit diagram of the small current parallel resonance energy extraction method according to an embodiment of the present invention.

[0019] Figure 5It is an equivalent circuit diagram of the large current coupled inductor energy extraction method according to an embodiment of the present invention.

[0020] Figure 6 It is a flow chart of a control method according to an embodiment of the present invention.

[0021] Figure 7 It is a simulation circuit model of the energy taking topology structure of an embodiment of the present invention.

[0022] Figure 8 It is a simulation result diagram of the large current coupled inductor energy harvesting method according to an embodiment of the present invention.

[0023] The names corresponding to the numbers in the accompanying drawings are defined as follows: 1. Damping core branch; 11. First secondary winding; 2. Energy extraction core branch; 21. Second secondary winding; 22. Tertiary winding; 23. Rectifier circuit; 24. Load; 3. Impedance control branch; 31. Impedance adjustment module (ie: TCLC module). DETAILED DESCRIPTION

[0024] The embodiments of the present invention will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention. In the description of the present invention, if there is a description of the first, the second, etc., it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features. If it involves the description of the orientation, such as the orientation or position relationship indicated by the upper and lower indications, the above-mentioned orientation description is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. Unless otherwise clearly defined, the terms such as setting, installing, connecting, etc. in the description of the present invention should be understood in a broad sense, and the technicians in the relevant technical field can reasonably determine the specific meaning of the above terms in the present invention in combination with the specific content of the technical solution.

[0025] like Figure 1As shown, this embodiment provides a transmission line wide current high power energy acquisition device, including a damping core branch 1, an energy acquisition core branch 2 and an impedance control branch 3, the damping core branch 1 includes an open air gap damping core T1 for sleeved on the transmission line, the open air gap damping core T1 is wound with a first secondary winding 11, the energy acquisition core branch 2 includes a closed energy acquisition core T2, a rectifier circuit 23 and a load 24, the closed energy acquisition core T2 is wound with a second secondary winding 21 and a tertiary winding 22, the tertiary winding 22 is connected to the rectifier circuit 23 and the load 24 in sequence, the central opening of the closed energy acquisition core T2 is inserted with a primary winding composed of parallel wires, and both ends of the primary winding are connected by The clamps or connecting terminals are connected to the two ends of the transmission line to which the open-gap damping core T1 is sleeved to connect the outer ring of the damping core branch 1 and the energy-taking core branch 2. The impedance control branch 3 includes an impedance adjustment module 31 and two relay switches K1 and K2. The impedance adjustment module 31 and the relay switch K1 are connected in series and arranged on a loop formed by connecting the first secondary winding 11 and the second secondary winding 21 end to end. One end of the relay switch K2 is connected to the middle node between the impedance adjustment module 31 and the relay switch K1, and the other end is connected to the wire between the first secondary winding 11 and the second secondary winding 21 to connect the inner ring of the damping core branch 1 and the energy-taking core branch 2.

[0026] like Figure 2 As shown, the impedance adjustment module (TCLC module) 31 of this embodiment is composed of two reverse parallel controlled thyristors T1 and T2, two inductance elements L f and L c and a compensation capacitor C f The two reverse parallel controlled thyristors T1 and T2 and the inductor element L f Then connect in series with the compensation capacitor C f The parallel branches are connected in parallel to form a parallel branch, and then the parallel branch and the inductor element are connected in parallel to form a parallel branch. L c Connected in series. Among them, T1 and T2 will be turned on alternately in the two half-waves of the same current cycle, and the conduction angle determines L f The time of working in the access circuit determines the working time within a cycle. L f The equivalent inductance value under the control of two controlled thyristors, the inductance value and the compensation capacitor C f For the parallel relationship, then in and coupling inductor L cUnder reasonable control, the entire impedance adjustment module can be equivalent to different capacitance values ​​or inductance values. Based on the two inductance elements L f and L c The function can be named as compensation inductance L f and coupled inductors L c , the equivalent impedance formula of the impedance adjustment module 31 is: , In the above formula, To compensate for the inductance The reactance, For compensation capacitor The reactance, Coupled Inductor L c The reactance, is the trigger angle of the thyristor. It can be seen that by adjusting the trigger angle α The size of the impedance adjustment module can make it present capacitance or inductance characteristics, and the size is adjustable.

[0027] In this embodiment, the closed energy-taking magnetic core T2 is designed with three windings, the number of turns of the primary winding formed by parallel wires is 1, and the number of turns of the second secondary winding 21 is less than the number of turns of the tertiary winding 22.

[0028] In this embodiment, the rectifier circuit 23 is a PWM rectifier circuit. The equivalent circuit principle of the PWM rectifier circuit is as follows: Figure 3 As shown in the figure, the PWM rectifier circuit mainly consists of two bridge arms composed of switch tubes VD1~VD4, among which U S Indicates the equivalent power supply, L S and R S is the equivalent inductance and equivalent resistance of the input end. The input power supply is connected to the midpoints A and B of the two bridge arms, and then the output voltage U is rectified by the two bridge arms. d According to the working principle of PWM rectifier circuit, by comparing the sine signal wave with the triangle wave, SPWM control is performed on V1-V4, and an SPWM wave U can be generated at the AC input terminals A and B of the bridge. AB When the frequency of the sine wave is the same as the frequency of the AC power supply, the current on the power supply side is also a sine wave with the same frequency as the power supply. By changing the SPWM wave U AB The amplitude and phase of the fundamental wave component can make the current and voltage of the AC power supply in the same direction. At this time, the circuit operates in a rectification state.

[0029] In actual situations, the current of the transmission line is determined by the load size, so the current fluctuates between tens to hundreds of amperes. To deal with this situation, the energy extraction topology in this embodiment can be controlled by a relay switch to provide two topologies, corresponding to two working modes. When the line current is greater than the preset lower limit threshold value and less than the critical saturation current, the relay switch K1 is closed and the relay switch K2 is opened. This topology structure is called a parallel resonance energy extraction mode; when the line current is greater than the critical saturation current and less than the preset upper limit threshold value, the relay switch K2 is closed and the relay switch K1 is opened. This topology structure is called a coupled inductor energy extraction mode. In this embodiment, the preset lower limit threshold value is 20A and the critical saturation current is 20A. I sat The preset upper limit threshold is 70A and 1000A.

[0030] When the line current is small, the core works in the non-saturation zone. By adjusting the secondary impedance to a capacitive load, the excitation effect can be increased. Turn off the relay switch K1, turn on the relay switch K2, the inner loop of the damping core branch 1 and the energy-taking core branch 2 are unlocked, and the two are only connected in parallel through a wire. The open-gap damping core T1 is regarded as an impedance. When the impedance is maximum, most of the line current will be transferred to the closed energy-taking core T2. By utilizing the high magnetic permeability characteristics of the closed energy-taking core T2, the core induction power can be greatly increased. Taking into account the internal excitation branch of the open-gap damping core T1, that is, including the excitation resistor R m and magnetizing inductance L m When the impedance adjustment module 31 on the secondary side of the air-gap damping core T1 is equivalent to a capacitor characteristic, the capacitor size is adjusted to resonate in parallel with the excitation inductance, and the equivalent impedance of the air-gap damping core T1 reaches a maximum value. Z d , the bus current will be diverted more to the energy-taking magnetic core branch 2, which will increase the energy-taking power.

[0031] Equivalent capacitance value when the impedance adjustment module 31 and the air-gap damping core T1 are in parallel resonance C eq for: , In the above formula, N 1 is the number of turns of the first secondary winding 11 of the air-gap damping core T1. At this time, the equivalent impedance of the air-gap damping core T1 reaches the maximum value. : , In the above formula, is the quality factor of the gapped damping core T1. It can be seen that the maximum value of the equivalent impedance of the gapped damping core T1 is proportional to the square of the quality factor. In order to further increase the impedance value, when designing the gapped damping core T1, it is necessary to increase the quality factor of the gapped damping core T1 as much as possible.

[0032] like Figure 4 As shown, the equivalent impedance of the damping core branch is Z max As the internal resistance of the current source, the number of turns on the third side of the energy core is designed N 2 can make the load impedance R L ′ Equal to the maximum value of damping impedance Z max According to the maximum power transfer theorem, load 24 can obtain the maximum power P max : , In the above formula, is the maximum power, is the effective value of the line current of the transmission line, is the magnetizing resistance of the air-gap damping core T1, is the quality factor of the gapped damping core T1.

[0033] Therefore, if Figure 6 As shown, this embodiment provides a control method for a transmission line wide current high power energy extraction device, comprising the following steps of extracting energy from a transmission line whose line current is greater than a preset lower limit threshold value and less than a critical saturation current: A1) Close the relay switch K2 and open the relay switch K1; A2) Adjust the trigger angles of the controllable thyristors T1 and T2 in the impedance adjustment module 31 so that the impedance of the impedance adjustment module 31 exhibits a capacitive characteristic and forms a parallel resonance with the excitation impedance of the open air gap damping core T1. At this time, the impedance of the impedance adjustment module 31 is: , , In the above formula, is the impedance of the impedance adjustment module 31, is the current angular frequency, The equivalent capacitance value of the parallel resonance formed by the excitation impedance of the impedance adjustment module 31 and the open-gap damping core T1; is the number of turns of the first and second windings 11, is the magnetizing resistance of the air-gap damping core T1, is the magnetizing inductance of the air-gap damping core T1; A3) The number of turns of the tertiary winding 22 is designed according to the size of the load 24 so that the impedance of the load 24 on the primary side of the closed energy-taking magnetic core T2 matches the impedance of the parallel resonance of the open air-gap damping magnetic core T1. At this time, the transmission line wide current and high power energy-taking device has the maximum power output.

[0034] The calculation function expression of the maximum power in step A3) of this embodiment is: , In the above formula, is the maximum power, is the effective value of the line current of the transmission line, is the magnetizing resistance of the air-gap damping core T1, is the quality factor of the air-gap damping core T1. In this embodiment, the preset lower limit threshold is 20A, and the critical saturation current is 70A.

[0035] When the line current is large, the magnetic core works in the saturation region, causing serious heating of the magnetic core and a large attenuation of the induced power. This embodiment provides an energy-taking topology, namely, a coupled inductor energy-taking mode. This mode requires closing the relay switch K2 and opening the relay switch K1. At this time, the outer rings of the damping core branch 1 and the energy-taking core branch 2 are connected by parallel wires, and the inner rings are connected through the impedance adjustment module 31 to form a double-ring coupling structure. It should be noted that the first secondary winding 11 and the second secondary winding 21 are connected end to end to form a loop, and the same-name end of the secondary winding of the open-gap damping core T1 is connected to the non-same-name end of the secondary winding of the closed energy-taking core T2, such as Figure 5 The outstanding feature of this topology is that when the line current I When it is large, the secondary windings of the two cores have a common current I c By adjusting the impedance of the impedance adjustment module 31 of the branch 3, the current is adjusted. I c Size, current at this time I c The energy-taking magnetic core current of the closed energy-taking magnetic core T2 I 2 has a phase reversal, which reduces the excitation of the closed energy-taking magnetic core T2 and achieves the anti-saturation effect of the magnetic core. Figure 5 In the dual-loop coupling structure shown in the figure, the internal loop is decoupled to obtain the damping core branch admittance. Y 1 and energy-taking magnetic core branch admittance Y 2 are: , , in, N 1 is the number of turns of the first secondary winding 11,N 2. N 3 are the turns of the second secondary winding 21 and the tertiary winding 22 respectively, R L is the load size, R m , L m It is divided into the excitation resistance and excitation inductance of the air-gap damping core T1. L eq is the equivalent inductance of the impedance adjustment module 31, ω is the current angular frequency. It can be seen that when the equivalent inductance of the impedance adjustment module 31 L eq When adjusting, the admittance of the damping core branch 1 Y 1 and the admittance of the energy-taking magnetic core branch 2 Y 2 will change, thus affecting the current shunting of the outer rings of the two core branches. From this, the port voltages of the two cores can be deduced: U S : , In the above formula, I is the line current. From the above formula, we can get that when the equivalent inductance of the impedance adjustment module is L eq When it becomes smaller, the terminal voltage of the magnetic core U S Will also become smaller; equivalent inductance L eq When it increases, the terminal voltage of the magnetic core U S However, the terminal voltage of the magnetic core U S It cannot be infinitely increased. Due to the core material and structure, the core port voltage has a saturation critical voltage value. U sat , using the above formula, to adjust the equivalent inductance L eq The size makes the terminal voltage of the core U S Less than the saturation threshold voltage U sat The anti-saturation effect of the magnetic core can be achieved.

[0036] The load power of the coupled inductor energy extraction mode in this embodiment P L for: , From the above formula, we can see that the load power in this mode is mainly related to the various parameters of the magnetic core and is proportional to the square of the line current. Using the above formula, the power output can be adjusted in the following three situations: (1) Line current I Unchanged, load R L When the equivalent inductance changes, the equivalent inductance can be dynamically adjusted L eq size to suit the load power requirements; (2) load R L unchanged, line current I When the equivalent inductance changes, the equivalent inductance can be dynamically adjusted L eq Size to stabilize load power demand; (3) Line current I and load R L When both change, the equivalent inductance can be dynamically adjusted L eq size to suit the load power requirements. Figure 6 As shown, the control method of this embodiment also includes the following steps of extracting energy from a transmission line whose line current is less than a preset upper limit threshold value and greater than a critical saturation current: B1) Close the relay switch K1 and open the relay switch K2; B2) Adjust the trigger angles of the controllable thyristors T1 and T2 in the impedance adjustment module 31 so that the impedance of the impedance adjustment module 31 presents an inductive characteristic to quickly resist the saturation of the magnetic core, and at this time the impedance of the impedance adjustment module 31 is: , In the above formula, is the impedance of the impedance adjustment module 31, is the current angular frequency, is the equivalent inductance of the impedance adjustment module 31; B3) Further adjust the inductance of the impedance adjustment module 31 by adjusting the trigger angle of the controllable thyristors T1 and T2 in the impedance adjustment module 31, so that the voltage across the closed energy-taking magnetic core T2 is less than the critical saturation voltage value of the magnetic core. At this time, the closed energy-taking magnetic core T2 operates in the non-saturation area and the power output of the transmission line wide current and high power energy-taking device to the load 24 is adjustable.

[0037] In step B3) of this embodiment, the calculation function expression of the power output by the transmission line wide current high power energy taking device to the load 24 is: , In the above formula, is the power output from the transmission line wide current high power energy taking device to the load 24, is the number of turns of the first and second windings 11, , are the turns of the second secondary winding 21 and the tertiary winding 22 respectively, is the effective value of the line current of the transmission line, For the size of the load 24, , are the excitation resistance and excitation inductance of the air-gap damping core T1, is the equivalent inductance of the impedance adjustment module 31, is the current angular frequency. In this embodiment, the preset upper limit threshold value is 1000A.

[0038] In order to verify the adaptability and high-power acquisition capability of the transmission line wide current high-power energy acquisition device and control method of this embodiment to the wide current of the transmission line, a simulation circuit model of the transmission line wide current high-power energy acquisition device is constructed in this embodiment. Figure 7 The effective value of the line current is set to 500A, and the number of turns of the first and second windings 11 of the air-gap damping core T1 is N 1 is set to a saturated transformer model of 1:18, the closed-end energy-taking magnetic core T2 is set to a multi-winding transformer model of 1:10:78, the load is 10Ω, and the trigger angle of the impedance adjustment module 31 is adjusted. α size, making its equivalent inductance L eq The load voltage waveform is recorded with three different values ​​of 1mH, 3mH and 5mH respectively. The simulation result waveform is as follows Figure 8 For a conventional energy-harvesting magnetic core, a 500A current excitation will immediately saturate the magnetic core, and the load induction voltage will be a peak wave. Figure 8 It can be seen that the load voltage obtained in this embodiment is a sine wave, and the load voltage is different under different equivalent inductances. When the inductance is larger, the load voltage is larger and the power is larger. When the equivalent inductance is 5mH, the load can reach a high power of 193W, which is consistent with the theoretical derivation. The simulation results prove that under high current conditions, by adjusting the equivalent inductance of the impedance adjustment module 31 L eq The load power can be effectively adjusted and sufficiently large power can be obtained at the same time, which illustrates the effectiveness of the wide current and large power energy acquisition device and control method for the power transmission line of this embodiment.

[0039] In summary, the wide current and high power energy acquisition device and control method for a transmission line described in this embodiment provide two working modes by controlling the on and off of two switches, respectively coping with scenes with small and large line currents. When the current is small, the parallel resonance method can greatly increase the inductive power output of the magnetic core. When the current is large, the saturation of the magnetic core can be effectively suppressed by adjusting the size of the coupling inductor, while outputting high power. In view of the characteristics of wide range fluctuations in line current and load changes, the output power can be adjusted by adjusting the impedance of the impedance adjustment module to meet the load power requirements. This embodiment solves the energy supply problem of high-power online equipment in transmission lines, has the advantages of simple structure, easy installation, fast response speed, and large inductive power, and has low control difficulty and cost, and can be widely used in high-voltage transmission line environments.

[0040] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A transmission line wide current high power energy extraction device, characterized in that: The invention comprises a damping magnetic core branch (1), an energy-taking magnetic core branch (2) and an impedance control branch (3), wherein the damping magnetic core branch (1) comprises an open air-gap damping magnetic core T1 for sleeved on a transmission line, the open air-gap damping magnetic core T1 being wound with a first secondary winding (11), the energy-taking magnetic core branch (2) comprising a closed energy-taking magnetic core T2, a rectifier circuit (23) and a load (24), the closed energy-taking magnetic core T2 being wound with a second secondary winding (21) and a tertiary winding (22), the tertiary winding (22) being connected to the rectifier circuit (23) and the load (24) in sequence, a primary winding consisting of parallel wires being inserted into a central opening of the closed energy-taking magnetic core T2, and two ends of the primary winding being connected via a clamp or a connection terminal. The impedance control branch (3) is connected to both ends of the power transmission line to which the air-gap damping magnetic core T1 is sleeved so as to connect the outer rings of the damping magnetic core branch (1) and the energy-taking magnetic core branch (2). The impedance control branch (3) comprises an impedance adjustment module (31) and two relay switches K1 and K2. The impedance adjustment module (31) and the relay switch K1 are connected in series and arranged on a loop formed by connecting the first secondary winding (11) and the second secondary winding (21) end to end. One end of the relay switch K2 is connected to the middle node between the impedance adjustment module (31) and the relay switch K1, and the other end is connected to the wire between the first secondary winding (11) and the second secondary winding (21) so as to connect the inner ring of the damping magnetic core branch (1) and the energy-taking magnetic core branch (2).

2. The transmission line wide current high power energy extraction device according to claim 1, characterized in that: The impedance adjustment module (31) comprises two reverse parallel controlled thyristors T1 and T2, two inductance elements L f and L c and a compensation capacitor C f The two reverse parallel controlled thyristors T1 and T2 and the inductor element L f After connecting in series, it is connected with the compensation capacitor C f The parallel branch is connected to form a parallel branch, and then the parallel branch and the inductor element L c Series connection.

3. The transmission line wide current high power energy acquisition device according to claim 1, characterized in that: The closed energy-taking magnetic core T2 is designed with three windings, the number of turns of the primary winding formed by parallel wires is 1, and the number of turns of the second secondary winding (21) is less than the number of turns of the tertiary winding (22).

4. The transmission line wide current high power energy extraction device according to claim 1, characterized in that: The rectifier circuit (23) is a PWM rectifier circuit.

5. A control method for a wide current and high power energy taking device for a power transmission line according to claim 3 or 4, characterized in that: The method comprises the following steps of extracting energy from a transmission line whose line current is greater than a preset lower limit threshold value and less than a critical saturation current: A1) Close the relay switch K2 and open the relay switch K1; A2) adjusting the trigger angles of the controllable thyristors T1 and T2 in the impedance adjustment module (31) so that the impedance of the impedance adjustment module (31) exhibits a capacitive characteristic and forms a parallel resonance with the excitation impedance of the open air gap damping core T1, and at this time, the impedance of the impedance adjustment module (31) is: ， ， In the above formula, is the impedance of the impedance adjustment module (31), is the current angular frequency, The equivalent capacitance value of the impedance adjustment module (31) and the excitation impedance of the air-gap damping core T1 forming a parallel resonance; is the number of turns of the first and second windings (11), is the magnetizing resistance of the air-gap damping core T1, is the magnetizing inductance of the air-gap damping core T1; A3) The number of turns of the tertiary winding (22) is designed according to the size of the load (24) so ​​that the impedance of the load (24) on the primary side of the closed energy-taking magnetic core T2 matches the impedance of the parallel resonance of the open air-gap damping magnetic core T1. At this time, the transmission line wide current and high power energy-taking device has maximum power output.

6. The control method of the transmission line wide current high power energy taking device according to claim 5, characterized in that: The calculation function expression of the maximum power in step A3) is: ， In the above formula, is the maximum power, is the effective value of the line current of the transmission line, is the magnetizing resistance of the air-gap damping core T1, is the quality factor of the gapped damping core T1.

7. The control method of the transmission line wide current high power energy taking device according to claim 5, characterized in that: The preset lower limit threshold value is 20A, and the critical saturation current is 70A.

8. The control method of the transmission line wide current high power energy taking device according to claim 5, characterized in that: The method also includes the following steps of extracting energy from a transmission line whose line current is less than a preset upper threshold value and greater than a critical saturation current: B1) Close relay switch K1 and open relay switch K2; B2) adjusting the trigger angles of the controllable thyristors T1 and T2 in the impedance adjustment module (31) so that the impedance of the impedance adjustment module (31) exhibits an inductive characteristic to quickly resist the saturation of the magnetic core, and at this time, the impedance of the impedance adjustment module (31) is: ， In the above formula, is the impedance of the impedance adjustment module (31), is the current angular frequency, is the equivalent inductance of the impedance adjustment module (31); B3) The inductance of the impedance adjustment module (31) is further adjusted by adjusting the trigger angle of the controllable thyristors T1 and T2 in the impedance adjustment module (31), so that the voltage across the closed energy-taking magnetic core T2 is less than the critical saturation voltage value of the magnetic core. At this time, the closed energy-taking magnetic core T2 operates in the non-saturation region and the power output of the transmission line wide current high power energy-taking device to the load (24) is adjustable.

9. The control method of the transmission line wide current high power energy taking device according to claim 8, characterized in that: In step B3), the calculation function expression of the power output by the transmission line wide current high power energy taking device to the load (24) is: ， In the above formula, is the power output from the wide current and high power energy taking device of the transmission line to the load (24), is the number of turns of the first and second windings (11), , are the number of turns of the second secondary winding (21) and the tertiary winding (22), respectively. is the effective value of the line current of the transmission line, is the size of the load (24), , are the excitation resistance and excitation inductance of the air-gap damping core T1, is the equivalent inductance of the impedance adjustment module (31), is the current angular frequency.

10. The control method of the transmission line wide current high power energy taking device according to claim 8, characterized in that: The preset upper limit threshold value is 1000A.

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