阅读说明：本技术 一种基于磁结构因子的无线电能传输系统磁场自显示装置 (Magnetic field self-display device of wireless power transmission system based on magnetic structure factor ) 是由 李佳承 邵如平 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种基于磁结构因子的无线电能传输系统磁场自显示装置,主要包括电流互感器、取能互感器、整流模块、调压模块、微处理器、AD模块和显示模块,根据耦合器机械结构定义磁结构因子,计算磁结构因子参数,通过测量耦合器工作时发射线圈和接收线圈中流过的电流,得到耦合器在空间某点产生的磁场强度。由于实际应用中耦合器工作时的结构和位置相对固定,采用本发明可实现测量耦合器线圈中的电流的同时获取并显示耦合器周围的磁场,解决了无线电能传输系统应用时磁场测量对专业化仪器的依赖,易于实现,实用性强。(The invention discloses a magnetic field self-display device of a wireless electric energy transmission system based on a magnetic structure factor, which mainly comprises a current transformer, an energy-taking transformer, a rectification module, a voltage regulation module, a microprocessor, an AD module and a display module, wherein the magnetic structure factor is defined according to the mechanical structure of a coupler, the parameter of the magnetic structure factor is calculated, and the magnetic field intensity generated by the coupler at a certain point in space is obtained by measuring the current flowing through a transmitting coil and a receiving coil when the coupler works. Due to the fact that the structure and the position of the coupler are relatively fixed during working in practical application, the magnetic field around the coupler can be obtained and displayed while the current in the coil of the coupler is measured, dependence of magnetic field measurement on specialized instruments during application of a wireless power transmission system is avoided, and the magnetic field measuring device is easy to achieve and high in practicability.)

1. A magnetic field self-display device of a wireless power transmission system based on magnetic structure factors comprises a current transformer, an energy-taking transformer, a rectifying module, a voltage regulating module, a microprocessor, an AD module and a display module; the current transformer is used for measuring the current in the transmitting coil or the receiving coil; the energy-taking mutual inductor is used for obtaining energy from the transmitting coil or the receiving coil; the rectifying module is used for converting the energy acquired by the energy-taking mutual inductor into direct current; the voltage regulating module is used for regulating and stabilizing the direct current voltage after the rectifying module and supplying energy to the AD module, the microprocessor and the display module; the AD module is used for converting the analog quantity acquired by the current transformer into digital quantity; and the microprocessor is used for receiving the coil current digital quantity converted by the AD module, acquiring the magnetic structure factor of the M point with the space coordinate of (x, y, z), combining the coil current digital quantity with the magnetic structure factor of the M point in the space, and calculating to obtain the magnetic field of the M point in the space around the coupler.

2. The magnetic structure factor-based wireless power transmission system magnetic field self-display device according to claim 1, wherein the display module is configured to display the magnetic field around the coupler.

3. The magnetic field self-display device of the wireless power transmission system based on the magnetic structure factor of claim 1, wherein the magnetic structure factor of the M point is obtained by the following method:

when the position of a spatial measured point M is fixed, the magnetic field strength of a single coil in the x, y and z directions in the space is expressed as:

wherein H_{coil_x}、H_{coil_y}And H_{coil_z}Respectively representing the magnetic field intensity generated by the coil in the x, y and z directions of a point M in space, I representing the effective value of the current flowing in the coil, and beta_xi、β_yiAnd beta_ziRespectively representing the magnetic structure factors of the ith turn of the coil in the x, y and z directions of a space M point, and N represents the number of turns of the coil.

4. The magnetic field self-display device of the wireless power transmission system based on the magnetic structure factor of claim 1, wherein the magnetic field calculation method of the M points in the space around the coupler is as follows:

the magnetic field of the coupler comprises the superposition of the transmitting coil magnetic field and the receiving coil magnetic field, the coil magnetic field being generated by an electric current, i.e. H ═ f (i);

when the WPT system works in a resonance state, the phase difference of 90 degrees exists between the current flowing through the transmitting coil and the current flowing through the receiving coil, and the instantaneous value of the current flowing through the transmitting coil is setThe instantaneous value of the current flowing in the receiving coil isWherein, I₁And I₂Respectively representing effective values of currents flowing in the transmitting coil and the receiving coil;

according to the definition of the magnetic field intensity instantaneous value, the magnetic field intensity instantaneous value generated by a single coil in the x, y and z directions of the M point in space is as follows:

wherein h is_x(t)、h_y(t) and h_z(t) instantaneous values of the magnetic field intensity generated by the single coil in the x, y and z directions at the point M in space, i (t) an instantaneous value of the current flowing in the coil, and instantaneous value h of the magnetic field generated by the coupler in the x direction at the point M in space_{coupler_x}(t) is obtained by superposing and calculating the magnetic field instantaneous values generated by the transmitting and receiving coils, namely:

wherein the content of the first and second substances,andthe magnetic structure factors of the transmitting coil and the receiving coil of the coupler in the X direction of the M point are respectively; instantaneous value h of magnetic field_{coupler_x}The root mean square value of (t) is:

similarly, the magnetic field strength generated by the coupler in the y direction and the z direction of the M point is respectively as follows:

5. the magnetic structure factor-based wireless power transmission system magnetic field self-display device according to claim 1, wherein the magnetic field strength at M points around the coupler is expressed as a relationship between a coil current and a magnetic structure factor:

wherein:

beta when the coordinates of both the coil structure and the measuring point M are constant_coil1And beta_coil2The self-display device can quickly display the magnetic field intensity of a fixed point around the coupler by measuring the current of the coil and the magnetic structure factor to be a fixed value.

Technical Field

The invention belongs to the technical field of wireless power transmission, and particularly relates to a magnetic field measuring device of a wireless power transmission system based on a magnetic structure factor, which is suitable for the wireless power transmission system containing an unshielded coupler.

Background

Wireless transmission media for energy include electric fields, magnetic fields, mechanical waves, microwaves, lasers, and the like. The magnetic field coupling type is a mode of a wireless power transmission technology which is widely applied at present, such as wireless charging of mobile phones, electric automobiles, rail transit, unmanned transportation vehicles, implanted medical equipment and the like. The magnetic field coupling type wireless power transmission technology is used for exciting a strong magnetic field to work in space through a transmitting coil of a coupler. Therefore, magnetic field safety around the magnetic field coupling type wireless power transmission system is receiving much attention. The traditional method for acquiring the magnetic field is obtained by introducing a magnetic field measuring instrument around the coupler and carrying out online real-time monitoring. Although the universality of the method is higher, the professional integration level is higher, and the method is not beneficial to the quick perception of the public to the magnetic field in practical application. In order to further enhance the efficiency of magnetic field acquisition of the wireless power transmission system and ensure accuracy and convenience, a new method for rapidly acquiring a magnetic field is needed to realize efficient sensing and display of the magnetic field of the wireless power transmission system.

Disclosure of Invention

The purpose of the invention is as follows: in order to solve the problems, the invention provides a magnetic field self-display device of a wireless power transmission system based on a magnetic structure factor, which is used for the wireless power transmission system with an unshielded coupler so as to realize the quick and efficient acquisition and display of the magnetic field of the coupler.

The technical scheme is as follows: the invention provides a magnetic field self-display device of a wireless power transmission system based on a magnetic structure factor, which comprises a current transformer, an energy-taking transformer, a rectification module, a voltage regulation module, a microprocessor, an AD module and a display module, wherein the current transformer is connected with the power-taking transformer; the current transformer is used for measuring the current in the transmitting coil or the receiving coil; the energy-taking mutual inductor is used for obtaining energy from the transmitting coil or the receiving coil; the rectifying module is used for converting the energy acquired by the energy-taking mutual inductor into direct current; the voltage regulating module is used for regulating and stabilizing the direct current voltage after the rectifying module and supplying energy to the AD module, the microprocessor and the display module; the AD module is used for converting the analog quantity acquired by the current transformer into digital quantity; and the microprocessor is used for receiving the coil current digital quantity converted by the AD module, acquiring the magnetic structure factor of the M point with the space coordinate of (x, y, z), combining the coil current digital quantity with the magnetic structure factor of the M point in the space, and calculating to obtain the magnetic field of the M point in the space around the coupler.

Further, the display module is used for displaying the magnetic field around the coupler.

Further, the method for obtaining the magnetic structure factor of the M point is as follows:

when the position of a spatial measured point M is fixed, the magnetic field strength of a single coil in the x, y and z directions in the space is expressed as:

wherein H_{coil_x}、H_{coil_y}And H_{coil_z}Respectively representing the magnetic field intensity generated by the coil in the x, y and z directions of a point M in space, I representing the effective value of the current flowing in the coil, and beta_xi、β_yiAnd beta_ziRespectively representing the magnetic structure factors of the ith turn of the coil in the x, y and z directions of a space M point, and N represents the number of turns of the coil.

Further, the magnetic field calculation method of the M points in the space around the coupler is as follows:

the magnetic field of the coupler comprises the superposition of the transmitting coil magnetic field and the receiving coil magnetic field, the coil magnetic field being generated by an electric current, i.e. H ═ f (i);

when the WPT system works in a resonance state, the phase difference of 90 degrees exists between the current flowing through the transmitting coil and the current flowing through the receiving coil, and the instantaneous value of the current flowing through the transmitting coil is setThe instantaneous value of the current flowing in the receiving coil isWherein, I₁And I₂Respectively representing effective values of currents flowing in the transmitting coil and the receiving coil;

according to the definition of the magnetic field intensity instantaneous value, the magnetic field intensity instantaneous value generated by the single coil in the X, Y and Z directions of the M point in space is

Wherein h is_x(t)、h_y(t) and h_z(t) instantaneous values of the magnetic field intensity generated by the single coil in the x, y and z directions at the point M in space, i (t) an instantaneous value of the current flowing in the coil, and instantaneous value h of the magnetic field generated by the coupler in the x direction at the point M in space_{coupler_x}(t) is obtained by superposing and calculating the magnetic field instantaneous values generated by the transmitting and receiving coils, namely:

wherein the content of the first and second substances,andthe magnetic structure factors of the transmitting coil and the receiving coil of the coupler in the X direction of the M point are respectively; instantaneous value h of magnetic field_{coupler_x}The root mean square value of (t) is:

similarly, the magnetic field strength generated by the coupler in the y direction and the z direction of the M point is respectively as follows:

further, the magnetic field strength at M points around the coupler is expressed as a coil current versus magnetic structure factor:

wherein:

beta when the coordinates of both the coil structure and the measuring point M are constant_coil1And beta_coil2The self-display device can quickly display the magnetic field intensity of a fixed point around the coupler by measuring the current of the coil and the magnetic structure factor to be a fixed value.

Has the advantages that: compared with the prior art, the invention has the beneficial effects that: the invention provides a magnetic field self-display device of a wireless electric energy transmission system based on a magnetic structure factor, which combines the current of the wireless electric energy transmission system and the measurement of a magnetic field by defining the magnetic structure factor of the magnetic field intensity generated by a coupler at a certain point in space, can realize the effect of obtaining the magnetic field intensity at the certain point in space by only measuring the current in a receiving and sending coil, can realize self-energy taking through the coupler, solves the problem that the magnetic field measurement in application depends on specialized instruments, and compared with the traditional measuring method, the method improves the measuring efficiency, is easy to realize and has strong practicability.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of magnetic field strength calculation for an unshielded planar coupler;

FIG. 3 is a schematic diagram of a biological proximity to a contact point of an outer envelope of a coupler;

FIG. 4 is a schematic diagram of the mechanical structure of the coupler; wherein (a) is a perspective view of a coupler coil winding structure; (b) a coupler prototype object diagram is shown;

FIG. 5 is a schematic diagram of the outer envelope of an unshielded planar coupler when it is aligned; wherein (a) is a schematic outer envelope at a distance of 30cm from the mechanical package of the coupler; (b) is a schematic view of the measurement points that the organism touches when approaching.

Detailed Description

The present invention is described in further detail below with reference to the attached drawing figures.

The invention provides a magnetic field self-display device of a wireless power transmission system based on a magnetic structure factor, as shown in fig. 1, Coil1 is a transmitting Coil, Coil2 is a receiving Coil, and Coil1 and Coil2 can be planar spiral circular coils or planar spiral square coils, as shown in fig. 2. The magnetic field self-display device of the wireless power transmission system based on the magnetic structure factor comprises a current transformer, an energy-taking transformer, a rectifying module, a voltage regulating module, a microprocessor, an AD module and a display module. The current transformer is used for measuring the current in the transmitting coil or the receiving coil; the energy-taking mutual inductor is used for obtaining energy from the transmitting coil or the receiving coil; the rectifying module is used for converting the energy acquired by the energy-taking mutual inductor into direct current; the voltage regulating module is used for regulating and stabilizing the direct current voltage after the rectifying module and supplying energy to the AD module, the microprocessor and the display module; the AD module is used for converting the analog quantity acquired by the current transformer into digital quantity; the microprocessor is used for receiving the coil current digital quantity converted by the AD module, acquiring the magnetic structure factor of the M point with the space coordinate of (x, y, z), combining the coil current digital quantity with the magnetic structure factor of the M point in the space, and calculating to obtain the magnetic field of the M point in the space around the coupler; the display module is used for displaying the magnetic field around the coupler.

The current transformer installed on the wire of the transmitting coil or the receiving coil induces a current value analog quantity in a fixed reduction proportion through the principle of electromagnetic induction, converts the current value analog quantity into a current value digital quantity through the AD module, and then transmits the current value digital quantity to the microprocessor.

The calculation process of the magnetic structure factor of the M point and the flow of the microprocessor for acquiring the magnetic structure factor are as follows: the relation between the magnetic field and the current of the coil at the M point in space is related to the structural parameters of the coil and the coordinates of the measuring point, a space rectangular coordinate system is established by taking the center of a transmitting coil of the coupler as an origin, and the proportional relation between the magnetic field and the current of the single coil at the M point in space in the x, y and z directions can be obtained based on Maxwell equations, namely:

wherein H_{coil_x}、H_{coil_y}And H_{coil_z}Respectively representing the magnetic field intensity generated by the coil in the x, y and z directions of a point M in space, I representing the effective value of the current flowing in the coil, and beta_xi、β_yiAnd beta_ziRespectively representing the magnetic structure factors of the ith turn of the coil in the x, y and z directions of a space M point, and N represents the number of turns of the coil.

Thus, the magnetic structure factor β of a single coil_xi、β_yiAnd beta_ziThe space rectangular coordinate system is based on the center origin of the transmitting coil, and the space rectangular coordinate system is obtained by substituting the coordinates of the M points into a Maxwell equation system for solving. Once the magnetic structure factor value is obtained, the magnetic structure factor value can be fixed into the microprocessor by the program code.

With the magnetic structure factor of a single coil, the magnetic field of the coupler is calculated as follows: the magnetic field of the coupler comprises the superposition of the magnetic field of the transmitting coil and the magnetic field of the receiving coil, which are generated by an electric current, i.e. H ═ f (i).

When the WPT system works in a resonance state, the phase difference of 90 degrees exists between the current flowing through the transmitting coil and the current flowing through the receiving coil, and the instantaneous value of the current flowing through the transmitting coil is setThe instantaneous value of the current flowing in the receiving coil isWherein, I₁And I₂Respectively representing the effective values of the currents flowing in the transmitting coil and the receiving coil.

According to the definition of the magnetic field intensity instantaneous value, the magnetic field intensity instantaneous value generated by a single coil in the x, y and z directions of the M point in space is as follows:

wherein h is_x(t)、h_y(t) and h_z(t) are respectively the single coil at M points in spaceI (t) represents the instantaneous value of the magnetic field flowing through the coil, and the instantaneous value h of the magnetic field in the x direction generated by the coupler at the point M in space_{coupler_x}(t) is obtained by superposing and calculating the magnetic field instantaneous values generated by the transmitting and receiving coils, namely:

wherein the content of the first and second substances,andrespectively, the magnetic structure factors of the transmitting coil and the receiving coil of the coupler in the x direction of the M point. Instantaneous value h of magnetic field_{coupler_x}The root mean square value of (t) is:

similarly, the magnetic field strength generated by the coupler in the y direction and the z direction of the M point is respectively as follows:

at present, when a coupler of a wireless power transmission system is produced, manufactured and delivered from a factory, the public cares about indexes such as power, efficiency, coil current and the like when the coupler works, and also cares about a magnetic field around the coupler. However, in practical application, specialized instruments are needed for measuring the magnetic field of the coupler, the specialized level is high, and high-frequency measurement and display are difficult to realize. In consideration of the fact that in application, the transmitting coil and the receiving coil of the coupler are fixed in position, and the magnetic field of a certain point in space is determined by the coil current and the coordinates of a measured point, therefore, when the coupler is delivered from a factory, a magnetic structure factor of a planned measuring point is written into a microprocessor in advance, so that in practical application, the magnetic field intensity of the measuring point can be obtained only by measuring the current flowing through the coil without the help of specialized instruments, the cost is low, the efficiency is high, and the public doubt is eliminated.

Thereby, the magnetic field strength H of M points around the coupler_couplerCan be expressed as a relationship of coil current to magnetic structure factor:

the calculation method of the magnetic structure factor of the coupler comprises the following steps:

therefore, the magnetic structure factor acquisition flow of the coupler: the magnetic structure factors of a single coil are defined, then the magnetic structure factors of the transmitting coil and the receiving coil in the x direction, the y direction and the z direction are calculated according to the phase difference of currents flowing in the transmitting coil and the receiving coil, and then the magnetic structure factors of the coupler are obtained through superposition calculation of the three directions.

Beta when the coordinates of both the coil structure and the measuring point M are constant_coil1And beta_coil2The self-display device can rapidly acquire and display the magnetic field intensity of the M point in the space around the coupler by measuring the current of the coil and the magnetic structure factor, wherein the magnetic field intensity is a fixed value.

When the centers of the transmitting Coil1 and the receiving Coil2 are aligned, and the outer envelope at a distance of 30cm from the mechanical enclosure of the coupler is set as the magnetic field evaluation region, as shown in fig. 5(a), when the biological body comes closer to the coupler, the most likely points of contact are the measurement point m, the measurement point p, and the measurement point q, as shown in fig. 3.

The center of the transmitting coil is taken as the origin of coordinates, and the length of the outer side of the transmitting coil is set to be l_1WThe length of the outer side of the receiving coil is l_2WAnd the coil transmission distance is d, and the coordinates of m points can be obtained through geometric transformation calculation: (0, - (0.5 l)_2W+0.3), d), the coordinates of point q are (0, - (0.5 l)_1W+0.3),0), the coordinates of the p points are:and d_pThen, it needs to be obtained by solving the equation:d can be obtained by solving equations easily through mathematical solving software_pThe value of (c).

The invention is further illustrated in the mechanical structure of the coupler as shown in fig. 4, where (a) is a perspective view of the winding structure of the coupler coil; (b) the coupler prototype object diagram is shown. The parameters of the mechanical structure of the coupler shown in fig. 4 are shown in table 1, and it can be obtained by the above method that the coordinates of the measurement point m in fig. 5(b) are (0, -0.515,0.2), the coordinates of the measurement point p are (0, -0.498,0.1), and the coordinates of the measurement point q are (0, -0.515, 0).

According to the parameters of the coupler coil, beta corresponding to the measuring point m, the measuring point p and the measuring point q can be obtained_coil1And beta_coil2As shown in table 2. Substituting the current of the transmitting-receiving coil measured in practical applicationThe magnetic field estimates can be compared to the actual measurements as shown in table 3.

TABLE 1 transmitting coil and receiving coil parameters

TABLE 2 magnetic structure factor of three measurement points

TABLE 3 comparison of calculated and measured values for three measurement points

According to the comparison of the results in table 3, the method for rapidly evaluating the magnetic field of the wireless power transmission system based on the magnetic structure factor can rapidly, accurately and efficiently acquire the magnetic field around the coupler without a professional magnetic field tester.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.