Bus wireless energy collection device and design method

Abstract

The invention discloses a bus wireless energy acquisition device and a design method, relates to a power transmission line energy acquisition device, and aims to solve the problems of unstable energy acquisition and short service life of an existing wireless sensor power supply mode. The bus wireless energy collection device comprises a plurality of magnetic cores, a coil and a compensation circuit, each magnetic core comprises two baffles and a magnetic bar; the two baffles are fixed to the two ends of the magnetic bar respectively. The magnetic bars of the plurality of magnetic cores are arranged in parallel; the coils are wound on the magnetic bars, and the coils wound on the magnetic bars of different magnetic cores are connected in series; and the compensating circuit is used for eliminating inductive reactance of the coil and realizing impedance matching. The beneficial effects are that the magnetic field energy around the bus is directly collected through the plurality of magnetic cores and coils without being influenced by external factors such as climate, day and night, the energy acquisition is stable, and the service life is long.

Description

Technical Field

[0001] This invention relates to a power transmission line energy harvesting device. Background Technology

[0002] With the rapid development of smart grids, the demand for online monitoring of the operating status of transmission lines is increasing. In order to achieve real-time perception of key parameters such as line temperature, icing, and vibration, it is usually necessary to deploy a large number of wireless sensors on transmission lines. However, the power supply problem of these sensors has become one of the key technical bottlenecks restricting their widespread application.

[0003] Currently, wireless sensors are mainly powered by battery power and environmental energy harvesting. Although battery power is simple in structure, it suffers from problems such as short lifespan, frequent maintenance, and high replacement costs due to limited battery capacity. In particular, its sustainability is poor in scenarios where frequent maintenance is difficult, such as high-voltage transmission lines. Therefore, it is of great significance to develop a stable and sustainable alternative power supply method.

[0004] Environmental energy harvesting technologies, such as solar and wind power, have a certain degree of self-powering capability, but they are greatly affected by natural factors such as climate and diurnal variations, resulting in unstable energy output and making it difficult to meet the continuous and reliable power requirements of wireless sensors.

[0005] In contrast, transmission lines possess stable and continuous magnetic field energy, especially near busbars where the magnetic field strength is high, offering excellent energy harvesting potential. Based on the principle of electromagnetic induction, an energy harvesting device composed of a magnetic core and coils can convert the magnetic field energy around the busbar into electrical energy, providing a stable power supply for wireless sensors. This method is independent of external weather conditions, has all-weather operation capability, and does not affect the normal operation of the power grid, making it a promising power supply solution. However, existing magnetic field energy harvesting devices still have many shortcomings in terms of structural design, material selection, and energy conversion efficiency. For example, unreasonable magnetic core shape and size can lead to uneven magnetic flux density distribution; improper selection of coil turns and wire diameter can increase losses and reduce output voltage; and insufficient consideration of eddy current losses and hysteresis losses in material selection results in low overall energy harvesting efficiency. Therefore, there is an urgent need for a busbar magnetic field energy harvesting device with optimized structure, reasonable materials, and stable performance to meet the power supply requirements of wireless sensors in smart grids. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of unstable energy acquisition and short service life of existing wireless sensor power supply methods, and to propose a bus wireless energy harvesting device and design method.

[0007] The bus wireless energy harvesting device of the present invention includes multiple magnetic cores, coils and compensation circuits;

[0008] Each magnetic core includes two baffles and a magnetic rod; the two baffles are fixed to both ends of the magnetic rod; the magnetic rods of the multiple magnetic cores are arranged in a parallel manner.

[0009] The coil is wound on a magnetic rod, and the coils wound on magnetic rods with different magnetic cores are connected in series.

[0010] The compensation circuit is used to eliminate the inductive reactance of the coil and achieve impedance matching.

[0011] Furthermore, the number of magnetic cores is four; the magnetic rods of the four magnetic cores are parallel to each other and their ends are arranged in a rectangular array, and the four baffles located at the same end are an integral structure.

[0012] Furthermore, the magnetic core is made of manganese-zinc ferrite material; the relative permeability of the manganese-zinc ferrite material is 2000, and the electrical conductivity is 1 S / m.

[0013] Furthermore, the coil uses copper wire with a diameter of 0.5mm, has three or fewer winding layers, and has a winding number of 200 to 800 turns.

[0014] A design method for a bus-based wireless energy harvesting device includes the following steps:

[0015] S1. Establish a magnetic field model for the busbar, and use simulation software to calculate and analyze the magnetic field distribution around the busbar to obtain the magnetic flux density around the busbar.

[0016] S2, determine the size and arrangement of the magnetic core based on the magnetic flux density around the busbar;

[0017] S3: Manganese-zinc ferrite is selected as the core material, and the aspect ratio of the magnetic rod is optimized to improve the effective permeability.

[0018] S4, design the coil parameters, including the number of turns, wire diameter and number of winding layers, and balance the induced voltage and the coil resistance.

[0019] S5. Construct a compensation circuit, select appropriate compensation capacitors and load resistors, and complete the design of a bus wireless energy harvesting device.

[0020] Furthermore, the simulation software is MATLAB or CST Studio.

[0021] Furthermore, the number of turns of the coil ranges from 200 to 800 turns; the diameter of the coil is 0.5 mm; and the number of winding layers of the coil is less than or equal to three.

[0022] Furthermore, the method for calculating the magnetic flux density around the busbar is as follows:

[0023] Modeling is performed on the busbar to simulate the distribution of the surrounding magnetic field when energized. The midpoint of the outer section on the left side of the busbar is set as the origin of the spatial rectangular coordinate system. The coordinates of a point outside the busbar are set as follows: (x, y, 0), with a busbar cross-sectional area of ​​S. A Establish a spatial rectangular coordinate system; in the direction of the busbar section, there exists a collection of finite linear currents;

[0024] (1)

[0025] in, Current density; The current flowing through the busbar; The cross-sectional length of the busbar; The cross-sectional height of the busbar;

[0026] The magnetic flux density at the point is:

[0027] (2)

[0028] in, This is the differential value of the magnetic flux density; Permeability in free space; From a certain point on the busbar to point The distance; according to formulas (1) and (2), Represented as:

[0029] (3)

[0030] The differential values ​​of the x-axis component and the y-axis component of the magnetic flux density are:

[0031] (4)

[0032] (5)

[0033] Substituting formula (3) into formulas (4) and (5) and performing integration, we obtain formulas (6) and (7).

[0034] (6)

[0035] (7)

[0036] (8)

[0037] in, The magnetic flux density around the busbar.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] Stable energy source: It directly collects magnetic field energy around the busbar through multiple magnetic cores and coils, unaffected by external factors such as climate and day / night cycles, ensuring stable energy acquisition and a long service life; High output power: The induced voltage of the series-connected coil structure on multiple magnetic cores can reach 13 times that of a single-segment structure, with a maximum output power of 19.2mW, far exceeding existing structures; Compact structure and easy installation: The device is small in size and can be directly installed on the busbar surface without affecting the operation of existing power facilities; Reasonable material selection: It adopts manganese-zinc ferrite cores and fine-diameter copper wires, balancing high permeability and low loss to improve energy conversion efficiency; Scientific design method: Combining simulation and experimental methods, the system optimizes key parameters to ensure optimal device performance. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure of a bus wireless energy harvesting device as described in Specific Implementation Method 1;

[0041] Figure 2 This is a side view of a bus wireless energy harvesting device according to a specific embodiment one;

[0042] Figure 3 This is a schematic diagram of the rectangular busbar model in Specific Implementation Method 1;

[0043] Figure 4 This is a schematic diagram of a cylindrical energy harvester that applies an alternating external magnetic field in Specific Implementation Method 1.

[0044] Figure 5 This is an equivalent circuit diagram of a bus wireless energy harvesting device in Specific Implementation Method 1;

[0045] Figure 6 This is a schematic diagram of the hysteresis loop of the hysteresis loop in Specific Implementation Method 1;

[0046] Figure 7 This is a schematic diagram of a three-phase busbar structure constructed using CST Studio in Specific Implementation Method 1;

[0047] Figure 8 This is a schematic diagram of the magnetic field distribution around the three-phase busbar in Specific Implementation Method 1;

[0048] Figure 9 This is a schematic diagram illustrating the change in magnetic flux density along the x-axis in Specific Implementation Method 1.

[0049] Figure 10 This is a schematic diagram illustrating the change in magnetic flux density along the y-axis in Specific Implementation Method 1.

[0050] Figure 11 This is a front view showing the dimensional design of a bus wireless energy harvesting device in Specific Implementation Method 1.

[0051] Figure 12 This is a physical image of a busbar wireless energy harvesting device in actual application according to Specific Implementation Method 1. Detailed Implementation

[0052] Specific Implementation Method 1: Combination Figures 1 to 12 This embodiment describes a busbar wireless energy harvesting device comprising multiple magnetic cores 1, coils 2, and a compensation circuit.

[0053] Each magnetic core 1 includes two baffles 1-1 and a magnetic rod 1-2; the two baffles 1-1 are respectively fixed at both ends of the magnetic rod 1-2; the magnetic rods 1-2 of the plurality of magnetic cores 1 are arranged in a parallel manner.

[0054] The coil 2 is wound on the magnetic rod 1-2, and the coils 2 wound on the magnetic rods 1-2 with different magnetic cores 1 are connected in series.

[0055] The compensation circuit is used to eliminate the inductive reactance of coil 2 and achieve impedance matching.

[0056] In this embodiment, the compensation circuit includes a compensation capacitor and a load resistor, which are used to eliminate coil inductive reactance and achieve impedance matching; the capacitance value of the compensation capacitor is set according to the coil inductance and the system operating frequency, and is used for resonance compensation to improve energy transmission efficiency.

[0057] The aforementioned busbar wireless energy harvesting device is installed on the surface of the busbar to collect magnetic field energy around the busbar and convert it into electrical energy output. The length of the magnetic rod at points 1-2 is 50.8 mm, the maximum diameter is 9.45 mm, and the outer diameter of the middle winding does not exceed 12.45 mm. Currently, the most common busbar cross-sectional shape is rectangular. To efficiently collect magnetic field energy, it is necessary to calculate and simulate the magnetic field conditions around the busbar. A model is created for the busbar to simulate the distribution of the surrounding magnetic field when energized. The midpoint of the outer left cross-section of the rectangular busbar is set as the origin of the rectangular coordinate system. The coordinates of a point outside the rectangular busbar are set as P(x, y, 0), and the cross-sectional area of ​​the busbar is S. A Establish a spatial rectangular coordinate system. A finite set of linear currents exists along the direction of the busbar section.

[0058] (1)

[0059] in Current density; The current flowing through the busbar; The cross-sectional length of the busbar; The cross-sectional height of the busbar;

[0060] The magnetic flux density at the point is:

[0061] (2)

[0062] in, ρ represents magnetic flux density, measured in Tesla. Permeability in free space; Let P be the distance from a point on the busbar to point P; according to formulas (1) and (2). Represented as:

[0063] (3)

[0064] The x-axis and y-axis components of the magnetic flux density are:

[0065] (4)

[0066] (5)

[0067] Substituting formula (3) into formulas (4) and (5) and performing integration, we obtain formulas (6) and (7).

[0068] (6)

[0069] (7)

[0070] (8)

[0071] Substitute the actual values ​​into the above formula and use MATLAB to simulate the magnetic field distribution around the three-phase busbar or use CST Studio to perform 3D modeling of the magnetic field.

[0072] At a frequency of 50Hz, the simplest and most effective method for harvesting magnetic field energy is to use a coil wound around a ferromagnetic core. This principle is based on Faraday's law: a changing current generates a time-varying magnetic field around the conductor; when this time-varying magnetic flux passes through the coil, an induced electromotive force is generated across the coil. Taking the most common cylindrical energy harvester as an example (e.g....) Figure 4 As shown in the figure, when an external magnetic field (Bex) is applied, the electromotive force is expressed as:

[0073] (9)

[0074] in, It is the effective value (root mean square value) of the induced electromotive force of the coil. It refers to the number of turns in the coil winding. It is the external magnetic flux density applied to the coil. It is the effective cross-sectional area of ​​the coil (unit: m). 2 ), It is angular frequency (unit: rad / s). It is the effective permeability related to the core material and core geometry.

[0075] Figure 5 The equivalent circuit of the system is shown; the electromotive force generated by the device is also shown. Used to power the entire test circuit. L represents the inductance of the energy harvester; R1 represents the coil resistance; R2 represents the load resistance; C is the compensation capacitor; the coil resistance R1 consists of the copper wire resistance and the core loss; the coil resistance R1 is related to the resistivity, length and cross-sectional area of ​​the copper wire; the core loss includes eddy current loss and hysteresis loss;

[0076] (10)

[0077] in, The resistance value of coil resistor R1 is: The resistivity of the copper wire is expressed in Ω·m. It is the length of the copper wire (unit: m). It is the cross-sectional area of ​​the copper wire (equal to) ),in It is the radius of the copper wire; the external circuit includes a compensation capacitor and a load, which are used to eliminate the inductive effect and match the resistive characteristics of the energy harvester, respectively; the output power reaches its maximum value when the load resistance R2 is equal to the coil resistance;

[0078] (11)

[0079] (12)

[0080] in, To compensate for the capacitance value of capacitor C; Inductor for energy harvester The inductance value; Output power to the load; The resistance value of the load resistor R2;

[0081] The power received by the load is shown in formula (12); from this, the power density is derived as:

[0082] (13)

[0083] in, It is the power density of the energy harvester, measured in mW / cm³; This refers to the volume of the energy harvester, measured in cm³. According to the output power expression, to maximize the output power, the voltage generated by the energy harvester needs to be increased. And reduce coil resistance Factors controlling these two variables include the shape and material of the magnetic core and the specifications of the copper wire; these factors will be analyzed and weighed in the design methodology of the energy harvester.

[0084] According to formula (9), the output power can be increased by controlling four variables, namely the effective permeability, the number of coil turns, the effective cross-sectional area of ​​the iron core, and the strength of the applied magnetic field. The external magnetic field strength is mainly changed by increasing the current, but this factor is not the focus of the study because it is not directly related to the energy harvester.

[0085] The demagnetization phenomenon determines the relative permeability of the core material, while the demagnetization field is related to the shape of the core.

[0086] (14)

[0087] in, An effective magnetic field; External magnetic field, As a demagnetizing factor, The magnetization intensity, The permeability is the vacuum permeability. Experiments show that the larger the ratio of length to diameter (i.e., the thinner and longer the core), the higher the effective permeability. However, long strips of metal are difficult to manufacture in industrial production and are prone to breakage; the ratio of length to diameter of cast iron cores needs to be limited to around 40, and for ferrite cores, it cannot even exceed 3; conversely, according to equation (9), increasing the effective cross-sectional area of ​​the core can increase the coil voltage, which contradicts the effect of reducing the demagnetizing field and increasing the effective permeability by thinning the core. Therefore, a trade-off must be made between these two variables.

[0088] Increasing the number of copper wire turns can improve coil voltage, but it also increases coil resistance, thus reducing output power. Furthermore, the thickness and length of the copper wire determine its resistance value, so the wire size must be carefully considered. Eddy current losses and hysteresis losses in the iron core also affect coil resistance. These factors affecting output power can be analyzed in detail, and the energy harvester can be designed accordingly.

[0089] In the selection of core materials, higher relative permeability means stronger magnetic permeability, which translates to greater magnetic flux per unit area. However, what directly affects the output power of the energy harvester is not the relative permeability, but the effective permeability. Higher relative permeability means stronger magnetic permeability, which translates to greater magnetic flux per unit area. However, what directly affects the output power of the energy harvester is not the relative permeability, but the effective permeability.

[0090] Eddy current loss and hysteresis loss are both part of the coil resistance; the core material is the key factor determining these two types of losses, so its impact on losses must be considered when selecting materials; the power consumption formula for eddy current loss is:

[0091] (15)

[0092] in, Cross-sectional area (unit: m²). For shape factor, Resistivity The magnetic flux density inside the magnetic core is denoted by . In a specific magnetic field, eddy current loss is directly proportional to the cross-sectional area and inversely proportional to the form factor and material resistivity. High-resistivity metals tend to impede eddy current transport, meaning that eddy current loss decreases as resistivity increases. Therefore, high-resistivity metals must be selected. Hysteresis loops are a standard method for characterizing ferromagnetic materials (e.g., . Figure 6 As shown in the diagram, the hysteresis loop of a material is defined by coercivity (Hc) and remanence (Br). Different applications have different requirements for the hysteresis loop characteristics of ferromagnetic materials. For example, the ferromagnetic material of a transformer core needs to have extremely low losses to achieve efficient energy conversion, and its low-loss characteristic can be manifested as a narrow hysteresis loop with a small area. The hysteresis loop of the core material used in energy harvesters must have this characteristic.

[0093] In summary, the core material should be a special ferromagnetic material with high relative permeability, high resistivity (low conductivity) and narrow hysteresis loop. Therefore, a manganese-zinc ferrite core with low conductivity and high relative permeability is adopted. Its relative permeability is 2000 and its conductivity is only 1 S / m, which fully meets the technical requirements.

[0094] As mentioned earlier, the specifications of the copper wire need to be carefully considered, as the number of turns and the resistance of the copper wire have opposite effects on the output power. Assuming an infinitely long copper wire is wound around a cylindrical magnetic core, the number of layers is:

[0095] (16)

[0096] in, Indicates the number of layers in the coil core. Indicates the total number of turns. Indicates the length of the cylindrical coil core. Indicates the diameter of the copper wire; using Indicates the total length of the copper wire:

[0097] (17)

[0098] in, Where is the core wire radius; according to formula (10), the resistance of the copper wire is:

[0099] (18)

[0100] Since the unit of copper wire diameter is usually millimeters, small changes will not have a significant impact on the winding resistance. Therefore, the length of copper wire is the main factor affecting the winding resistance. According to formula (17), the length of copper wire is mainly determined by the number of winding layers. As the number of layers on the iron core continues to increase, the length of copper wire consumed per layer increases accordingly. In actual testing, the number of copper wire layers wound on the magnetic core should not be too many, but the number of turns per layer should be increased as much as possible—because increasing the number of turns can increase the coil voltage, thereby increasing the output power. In summary, in order to increase the number of turns per winding layer and reduce the number of layers, a relatively small diameter copper wire should be used. Therefore, a copper wire with a diameter of 0.5 mm is used, and the number of layers must be controlled.

[0101] As mentioned earlier, thin ferromagnetic materials exhibit higher effective permeability and higher coil voltage. The performance of ferromagnetic materials of different lengths was verified using CSTStudio, with the material's relative permeability set at 2000 and the magnetic field source strength at 1 A / m. The magnetic flux density in the dumbbell-shaped winding section showed little variation on both sides, essentially remaining at its maximum value. Comparing this design with an 80 mm long cylindrical magnetic core (with no significant difference in total length), the former produced a much higher maximum magnetic flux density and tended to stabilize in the winding section. Therefore, this design will serve as a prototype for the magnetic core.

[0102] The distribution of the magnetic field around the busbar determines the size of the energy harvester. The magnetic field distribution can be observed more intuitively using CST Studio software, which uses 3D models for simulation. Figure 7 The three yellow rectangular plates in the center represent a three-phase aluminum busbar, with dimensions of 200mm long, 40mm wide, and 10mm high (the same as the aluminum plates used in the actual experiment). Assume that three-phase currents with a phase difference of 120 degrees flow along the centerline of the busbar. Figure 8 It can be concluded that the magnetic field is uniformly distributed and concentrated on the surface of the busbar.

[0103] To further confirm the distribution of magnetic flux density, the distribution along the x-axis and y-axis was analyzed separately. Figure 9 This diagram illustrates the variation of magnetic flux density along the x-axis, with the magnetic flux density located at the center of space along the x-axis. The magnetic field strength is mainly concentrated within a range slightly larger than the width of the generatrix, and its distribution is basically consistent near the three generatrixes. Figure 10 This diagram illustrates the variation of magnetic flux density along the y-axis, with the flux density located at the center of space along the y-axis. The vertical distribution of the magnetic field is mainly concentrated in the region from 12 mm directly above to 12 mm directly below the busbar. Based on the magnetic flux density distribution in these two directions, the core specifications and the number of winding layers can be determined.

[0104] The magnetic flux density distribution near each phase of the three-phase busbar is basically the same. Therefore, to simplify the system, only an energy harvester is needed to collect the magnetic field energy around each single-phase busbar. Figure 11 This is a dimensional design drawing of the energy harvester placed on the busbar; the cylindrical magnetic core is 50.8 mm long and 9.45 mm in diameter, forming a dumbbell-shaped core with a dual-guide device. Only three layers of copper wire (0.5 mm in diameter) are wound around the core to reduce resistance and cost. The total diameter of the winding section is 12.45 mm, conforming to... Figure 10 The magnetic flux density distribution obtained from the analysis (12 mm above and below the busbar).

[0105] The busbar wireless energy harvesting device described in this embodiment consists of four identical coils 2 connected in series, with a structure similar to the previously designed dumbbell-shaped energy harvester. Two sections are located above the busbar, and the other two sections are located below the busbar. Each group of coils has the same winding direction as the coils on the same side, but the opposite direction to the coils on the opposite side. Similar to the dumbbell-shaped magnetic core, two rectangular disks of the same size are used as guides on both sides.

[0106] Compared to a single dumbbell-shaped energy harvester, the bus wireless energy harvesting device described in this embodiment adds a coil on each side of the bus to increase the output power. Figure 2 and Figure 11 The side and front views of the described busbar wireless energy harvesting device are shown respectively; four coils are firmly attached to the busbar surface, and the entire device has a symmetrical structure. To verify the performance of the described busbar wireless energy harvesting device and a single dumbbell-shaped energy harvester, a comparative test similar to previous tests was conducted. The busbar is an aluminum plate with dimensions of 200mm × 40mm × 10mm (length × width × height). A hole is symmetrically located on each side of the aluminum plate, and the connecting wire is wound around a through-hole screw to ensure even current flow through the busbar. An identical AC generator is used as the power source, and a high-rated-current sliding resistor is used as the current control device. Because the system has a high current of nearly 20A, ordinary wires may be damaged due to exceeding the rated current. The solution is to use multi-strand copper wire cables with a higher rated current to replace standard wires for connecting the equipment. The aforementioned busbar wireless energy harvesting device design employs four times the number of copper wire turns compared to the dumbbell-shaped energy harvester. While this increases the coil voltage, it also increases the coil resistance. As analyzed earlier, the copper wire resistance is primarily related to the number of layers. In this design, the number of copper wire layers per ferrite core remains unchanged (3 layers), with only four identical coils connected in series. Therefore, compared to the increased coil resistance, this design can raise the coil voltage to a higher level, thereby generating significantly greater output power.

[0107] The table below lists the parameter values ​​for each shape. Since the number of copper wire turns in the bus wireless energy harvesting device described in this embodiment is four times that of the dumbbell-shaped energy harvester, its inductance is also increased to 50mH. The compensation capacitor values ​​for these two designs are 1.6mF and 202.6μF, respectively.

[0108]

[0109] Experiments showed that the electromotive force (EMF) of the dumbbell-shaped energy harvester was linearly related to the current, while the new energy harvester exhibited a rapid increase and no obvious linear characteristic. The former's EMF change rate with current was 4.5 mV / A, much lower than the latter (approximately 58 mV / A). When the current reached 17 amperes, the new energy harvester could generate a voltage of 986.4 millivolts, 13 times that of the dumbbell-shaped energy harvester (75.9 millivolts). The output power reached its maximum value of 0.68 mW and 19.2 mW when the load resistance equaled the internal resistance of the energy harvesting device. Based on the output parameter values ​​in the two designs, it can be concluded that the magnetic field energy harvesting capability of the bus wireless energy harvesting device described in this embodiment is far superior to that of the dumbbell-shaped energy harvester. Therefore, the bus wireless energy harvesting device described in this embodiment can be used to harvest magnetic field energy near the bus to power wireless sensors.

[0110] Specific Implementation Method Two: This implementation method further defines the bus wireless energy harvesting device described in Specific Implementation Method One. In this implementation method, the number of magnetic cores 1 is four; the magnetic rods 1-2 of the four magnetic cores 1 are parallel to each other and arranged in a rectangular array at their ends, and the four baffles 1-1 located at the same end are integrated into one structure.

[0111] In this embodiment, the number of magnetic cores 1 is further limited to four, and a symmetrical layout (two on the top and two on the bottom) is adopted, resulting in a larger magnetic field capture area and higher energy harvesting efficiency. The integrated design of the left and right baffles makes the structure more stable, facilitates mass production and installation, and improves system consistency and reliability.

[0112] Specific Implementation Method 3: This implementation method further defines the bus wireless energy harvesting device described in Specific Implementation Method 2. In this implementation method, the magnetic core 1 is made of manganese-zinc ferrite material; the relative permeability of the manganese-zinc ferrite material is 2000, and the electrical conductivity is 1 S / m.

[0113] In this embodiment, the core material is specified as manganese-zinc ferrite, which has a relative permeability of up to 2000 and an electrical conductivity as low as 1 S / m, effectively suppressing eddy current loss and hysteresis loss, and further improving energy conversion efficiency. The material selection is scientific and reasonable, taking into account both high permeability and low loss, providing a basic guarantee for efficient energy harvesting.

[0114] Specific Implementation Method Four: This implementation method further defines the bus wireless energy harvesting device described in Specific Implementation Method One. In this implementation method, the coil 2 uses copper wire with a diameter of 0.5mm, has three or fewer winding layers, and has a winding turn range of 200 to 800 turns.

[0115] In this embodiment, the coil parameters are defined as follows: 0.5mm fine copper wire is used, with 200 to 800 turns and no more than 3 winding layers. This effectively controls the resistance while increasing the induced voltage, avoiding excessive energy loss. The parameter range is clearly defined, which facilitates engineering implementation and standardized production, balancing performance and cost.

[0116] Specific Implementation Method Five: This implementation method is a design method for a bus wireless energy harvesting device as described in Specific Implementation Method Three, and includes the following steps:

[0117] S1. Establish a magnetic field model for the busbar, and use simulation software to calculate and analyze the magnetic field distribution around the busbar to obtain the magnetic flux density around the busbar.

[0118] S2, determine the size and arrangement of magnetic core 1 based on the magnetic flux density around the busbar;

[0119] S3, manganese zinc ferrite was selected as the material of magnetic core 1, and the aspect ratio of magnetic rod 1-2 was optimized to improve the effective permeability;

[0120] S4, design the parameters of coil 2, including the number of turns, wire diameter and number of winding layers, and balance the induced voltage and the resistance value of coil 2;

[0121] S5. Construct a compensation circuit, select appropriate compensation capacitors and load resistors, and complete the design of a bus wireless energy harvesting device.

[0122] This embodiment provides a scientific design method, including steps such as magnetic field modeling, magnetic core selection, coil design, and compensation circuit construction, which scientifically guides device design and avoids trial and error; through the combination of simulation and optimization, it ensures that the device has the best performance and highest efficiency in practical applications.

[0123] Specific Implementation Method Six: This implementation method further defines the design method of a bus wireless energy harvesting device described in Specific Implementation Method Five. In this implementation method, the simulation software is MATLAB or CST Studio.

[0124] In this embodiment, the simulation tool is specified as MATLAB or CST Studio, which has powerful electromagnetic field modeling and simulation capabilities, and can accurately predict the magnetic field distribution around the busbar and the output performance of the device; thereby improving design efficiency and accuracy, reducing the number of experiments, and shortening the R&D cycle.

[0125] Specific Implementation Method Seven: This implementation method further defines the design method of a bus wireless energy harvesting device described in Specific Implementation Method Five. In this implementation method, the number of turns of the coil 2 is in the range of 200 to 800 turns; the diameter of the coil 2 is 0.5 mm; and the number of winding layers of the coil 2 is less than or equal to three layers.

[0126] In this embodiment, the range of coil parameters (number of turns, wire diameter, number of layers) is clarified again to enhance the operability and consistency of the design; it provides a clear basis for subsequent mass manufacturing, performance reproduction and quality control, and reduces the risk of production variation.

[0127] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A busbar wireless energy harvesting device, characterized in that, It includes multiple magnetic cores (1), coils (2) and compensation circuits; each magnetic core (1) includes two baffles (1-1) and a magnetic rod (1-2); the two baffles (1-1) are respectively fixed at both ends of the magnetic rod (1-2); the magnetic rods (1-2) of the multiple magnetic cores (1) are arranged in a parallel manner. The coil (2) is wound on the magnetic rod (1-2), and the coils (2) wound on the magnetic rods (1-2) with different magnetic cores (1) are connected in series; The compensation circuit is used to eliminate the inductive reactance of the coil (2) and achieve impedance matching.

2. The bus wireless energy harvesting device according to claim 1, characterized in that, The number of magnetic cores (1) is four; the magnetic rods (1-2) of the four magnetic cores (1) are parallel to each other and arranged in a rectangular array at their ends, and the four baffles (1-1) located at the same end are integrated into one structure.

3. A busbar wireless energy harvesting device according to claim 2, characterized in that, The magnetic core (1) is made of manganese zinc ferrite material; the relative permeability of the manganese zinc ferrite material is 2000 and the electrical conductivity is 1 S / m.

4. A busbar wireless energy harvesting device according to claim 1, characterized in that, The coil (2) uses copper wire with a diameter of 0.5 mm, with no more than three layers and a number of turns ranging from 200 to 800.

5. A design method for a bus wireless energy harvesting device based on claim 3, characterized in that, Includes the following steps: S1. Establish a magnetic field model for the busbar, and use simulation software to calculate and analyze the magnetic field distribution around the busbar to obtain the magnetic flux density around the busbar. S2, determine the size and arrangement of the magnetic core (1) based on the magnetic flux density around the busbar; S3, manganese zinc ferrite was selected as the core material (1), and the aspect ratio of the magnetic rod (1-2) was optimized to improve the effective permeability; S4, design the parameters of coil (2), including the number of turns, wire diameter and number of winding layers, and balance the induced voltage and the resistance value of coil (2); S5, construct the compensation circuit, select appropriate compensation capacitor and load resistor, and complete the design of a bus wireless energy harvesting device.

6. The design method of a busbar wireless energy harvesting device according to claim 5, characterized in that, The simulation software is MATLAB or CST Studio.

7. The design method of a busbar wireless energy harvesting device according to claim 5, characterized in that, The number of turns of the coil (2) ranges from 200 to 800; the diameter of the coil (2) is 0.5 mm; and the number of winding layers of the coil (2) is less than or equal to three.

8. The design method of a busbar wireless energy harvesting device according to claim 5, wherein the magnetic flux density around the busbar is calculated as follows: Modeling is performed on the busbar to simulate the distribution of the surrounding magnetic field when energized. The midpoint of the outer section on the left side of the busbar is set as the origin of the spatial rectangular coordinate system. The coordinates of a point outside the busbar are set as follows: (x, y, 0), with a busbar cross-sectional area of ​​S. A Establish a spatial rectangular coordinate system; in the direction of the busbar section, there exists a collection of finite linear currents; （1） in, Current density; The current flowing through the busbar; The cross-sectional length of the busbar; The cross-sectional height of the busbar; The magnetic flux density at the point is: （2） in, This is the differential value of the magnetic flux density; Permeability in free space; From a certain point on the busbar to point The distance; according to formulas (1) and (2), Represented as: （3） The differential values ​​of the x-axis component and the y-axis component of the magnetic flux density are: （4） （5） Substituting formula (3) into formulas (4) and (5) and performing integration, we obtain formulas (6) and (7). （6） （7） （8） in, The magnetic flux density around the busbar.

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