CN102832721B - Adjusting method for coil air gap of energy taking power supply - Google Patents

Abstract

The invention provides an adjusting method for a coil air gap of an energy taking power supply, comprising the following steps: the cutoff current and saturation current of a coil without an air gap are obtained; the saturation current of the coil with the air gap is obtained according to the saturation current of the coil without the air gap; the input current of the primary side of the coil with the air gap is obtained; the voltage change relation of the secondary side of the coil before and after the air gap is added to the coil is obtained according to the input current, the cutoff current, and the saturation current of the coil with the air gap; the coil air gap required to be adjusted is obtained according to the target induction voltage and the voltage change relation; and the actual coil air gap of the energy taking power supply is adjusted according to the coil air gap required to be adjusted. The influence of the adjusted coil air gap of the energy taking power supply on the induction voltage can be quantitative, and the actual coil air gap of the power supply can be accurately adjusted according to the induction voltage needing to be obtained.

Description

A method for adjusting the air gap of an energy harvesting power supply coil

technical field

The invention relates to the technical field of electromagnetic induction, in particular to a method for adjusting the air gap of an energy harvesting power supply coil.

Background technique

With the development of national smart grid work and the continuous improvement of the voltage level of transmission lines, it is particularly important to conduct online monitoring of the safe operation of transmission lines. In order to supply power to various on-line monitoring systems working on the high-voltage side of transmission lines, it is necessary to develop a long-term stable and reliable power supply on the high-voltage side.

Among them, the inductive energy harvesting power supply has strong practicability and is the most promising power supply method. In the current inductive energy harvesting power supply, in order to avoid the deep saturation of the coil, a control circuit, a compensation circuit, etc. are added to adjust the complexity of the working state of the coil. circuit, which complicates the power supply circuit and reduces reliability.

However, when the actual monitoring system inductive energy harvesting power supply product is tested, different degrees of coil vibration occur, because when the coil is in a deeply saturated state, the core loss increases, causing the coil to vibrate. In order to solve this problem, the saturation can be reduced by introducing the coil air gap reluctance to increase the current application range, but most of them only conduct qualitative analysis on the influence of the coil air gap, and there is no clear method to quantitatively increase the coil air gap. The influence of induced voltage; thus, it brings inconvenience to the application of induction energy harvesting. In practical applications, it is difficult to determine the voltage for the required induced electric energy and how to adjust the air gap of the power supply coil.

Contents of the invention

The purpose of the present invention is to propose a method for adjusting the coil air gap of the energy harvesting power supply, which can quantify the influence of adjusting the coil air gap of the energy harvesting power supply on the induced voltage, and accurately adjust the actual coil air gap of the power supply according to the induced voltage to be obtained .

In order to achieve the above purpose, the technical scheme adopted is:

A method for adjusting the air gap of an energy harvesting power supply coil, comprising the steps of:

Obtain the cut-off current and saturation current of the coil when the air gap is not added;

According to the saturation current of the coil when the air gap is not increased, obtain the saturation current of the coil when the air gap is increased;

Obtain the input current of the primary side of the coil when the air gap is increased;

According to the input current, the cut-off current and the saturation current of the coil when the air gap is increased, the voltage change relationship of the secondary side of the coil before and after the air gap of the coil is increased;

Obtain the coil air gap to be adjusted according to the relationship between the target induced voltage and the voltage change;

According to the coil air gap to be adjusted, adjust the actual coil air gap of the energy harvesting power supply.

The present invention obtains the cut-off current and saturation current of the coil when there is no air gap according to the data and relationship curve of the primary side current without air gap and the induced voltage of the secondary side; In different regions, the relationship between the induced voltage and the induced voltage on the secondary side of the coil when the air gap is not increased under the same input current; Air gap width: the influence of adjusting the coil air gap of the energy harvesting power supply on the induced voltage can be quantified, and the actual coil air gap of the power supply can be accurately adjusted according to the induced voltage to be obtained.

Description of drawings

Fig. 1 is a flowchart of an embodiment of the present invention.

Detailed ways

For ease of understanding, the present invention will be described below in conjunction with the accompanying drawings.

A method for adjusting the air gap of an energy harvesting power supply coil, please refer to Figure 1, including steps:

S101. Obtain the cut-off current and saturation current of the coil when the air gap is not increased;

S102. Obtain the saturation current of the coil when the air gap is increased according to the saturation current of the coil when the air gap is not increased;

S103. Obtain the input current of the primary side of the coil when the air gap is increased;

S104, according to the input current, the cut-off current and the saturation current of the coil when the air gap is increased, obtain the voltage change relationship of the secondary side of the coil before and after the air gap of the coil is increased;

S105. Obtain the coil air gap to be adjusted according to the relationship between the target induced voltage and the voltage change;

S106. Adjust the actual coil air gap of the energy harvesting power supply according to the coil air gap to be adjusted.

The present invention obtains the cut-off current and saturation current of the coil when there is no air gap according to the data and relationship curve of the primary side current without air gap and the induced voltage of the secondary side; In different regions, the relationship between the induced voltage and the induced voltage on the secondary side of the coil when the air gap is not increased under the same input current; Air gap width: the influence of adjusting the coil air gap of the energy harvesting power supply on the induced voltage can be quantified, and the actual coil air gap of the power supply can be accurately adjusted according to the induced voltage to be obtained.

For a clearer understanding of the present invention, it will be set forth from the following parts:

1. Obtain the cut-off current and saturation current of the coil when the air gap is not increased;

According to the data and relationship curve of the primary side current and the secondary side induced voltage of the non-gap coil, the cut-off current and saturation current of the coil without air gap can be obtained; in the specific implementation, the primary side current and the current of the non-gap coil can be first The data and relationship curve of the induced voltage on the secondary side are imported into the system, so that in the process of the present invention, the cut-off current and saturation current of the coil when there is no air gap can be obtained directly from the system end.

2. Obtain the saturation current of the coil when the air gap is increased according to the saturation current of the coil when the air gap is not increased;

Specifically, steps A and B may be included;

A. According to the formula B _m = μ ₀ μ _Fe H _m and μ _r = μ ₀ μ _Fe to obtain the relative magnetic permeability of the coil;

B. According to the formula and B _m ＝μ ₀ μ _Fe H _Fe ＝μ ₀ μ _δ H _δ get the saturation current of the coil when the air gap is increased; where, I _m is the saturation current of the coil when the air gap is increased; B _m is the saturation magnetic induction; H _m is the total magnetic field strength; H _δ is the magnetic field strength of the air gap; H _Fe is the magnetic field strength of the iron material; l _δ is the length of the coil air gap; l _Fe is the _length of the iron core magnetic circuit; The saturation current of the coil during the gap; N ₁ is the primary side coil turns of the coil; μ _Fe is the magnetic permeability of the iron material; μ _r is the relative magnetic permeability of the coil, and μ ₀ is the vacuum magnetic permeability; μ _δ is The relative magnetic permeability of air is 1.

According to the parameters of the iron core of the energy-taking coil, look up the working condition table, and you can know the saturation magnetic induction B _m of the coil, the magnetic permeability μ _Fe of the iron core, the lamination coefficient λ of the iron core, the cross-sectional area S of the iron core, and the coil The current I input by the primary side, the number of turns N ₁ on the primary side of the coil, the length of the total magnetic circuit l, the length of the iron core magnetic circuit l _Fe ; the length of the air gap magnetic circuit l _δ , the grid voltage frequency f; the number of turns of the secondary side coil N ₂ . When in the saturation region, the magnetic induction intensity is a constant value, that is, B _m =1.25T (Stella), μ _δ =1.

3. Obtain the input current of the primary side of the coil when the air gap is increased;

The input current of the primary side of the coil when the air gap is increased, the system can be obtained through the measurement tool.

4. According to the input current, the cut-off current and the saturation current of the coil when the air gap is increased, the voltage change relationship of the secondary side of the coil before and after the air gap of the coil is increased;

The present invention obtains the induced voltage of the secondary side of the coil after the air gap is increased from three different areas of the linear region, the gradual saturation region and the saturation region, and compares the change of the induced voltage of the secondary side of the coil when the air gap is not increased under the same input current Relationship; specifically, including steps:

C. According to the formula Get the coil secondary side voltage saturation value when increasing the air gap;

D. When the input current is less than the cut-off current, that is, in the linear region,

According to the formula Get the voltage change value on the secondary side of the coil:

E. When the input current is greater than or equal to the cut-off current and less than the saturation current of the coil when the air gap is increased, that is, when it is in the gradual saturation region;

According to the formula Get the voltage variation range of the secondary side of the coil;

F. When the input current is greater than or equal to the saturation current of the coil when the air gap is increased, that is, when it is in the saturation region;

According to the formula ΔU=U, the voltage change value of the secondary side of the coil is obtained; when it is in the saturation region, the voltage change value of the secondary side of the coil is a constant value.

Among them, U=U ₀ -U ₂ ; U ₂ is the voltage saturation value of the secondary side of the coil when the air gap is increased; ΔU is the voltage change value of the secondary side of the coil; f is the current voltage frequency of the grid; N ₂ is the secondary side of the coil Secondary side coil turns; S is the cross-sectional area of the iron core; λ is the lamination coefficient of the iron core; I ₁ is the cut-off current; I is the input current; _l is the total magnetic circuit length of the coil; Secondary side voltage saturation value.

5. Obtain the coil air gap that needs to be adjusted according to the relationship between the target induced voltage and the voltage change;

It can be obtained from step four that when the air gap of the coil is increased, the change of the induced voltage corresponding to the secondary side of the coil can be obtained according to the size of the target induced voltage to be obtained, the induced voltage of the secondary side of the coil when there is no coil air gap, and the induced voltage in step four The obtained voltage change relationship can obtain the coil air gap value that needs to be adjusted.

When the air gap of the coil is not increased, the induced voltage on the secondary side of the coil can be obtained by ordinary technicians according to relevant parameters.

6. According to the coil air gap to be adjusted, adjust the actual coil air gap of the energy harvesting power supply.

The system adjusts the coil air gap value as needed, and adjusts the actual coil air gap of the energy harvesting power supply, so that the energy harvesting power supply outputs a voltage consistent with the target induced voltage.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (1)

1. A method for adjusting the air gap of an energy-taking power supply coil, comprising the steps of: According to the data and relationship curve of the primary side current and the secondary side induced voltage of the non-air gap coil, the cut-off current and saturation current of the coil when the air gap is not added are obtained; Obtaining the saturation current of the coil when the air gap is increased according to the saturation current of the coil when the air gap is not increased; Obtain the input current of the primary side of the coil when the air gap is increased; According to the input current, the cut-off current, and the saturation current of the coil when the air gap is increased, the voltage change relationship of the secondary side of the coil before and after the air gap of the coil is increased; Obtain the coil air gap to be adjusted according to the relationship between the target induced voltage and the voltage change; According to the coil air gap to be adjusted, adjust the actual coil air gap of the energy harvesting power supply, The step of obtaining the saturation current of the coil when the air gap is increased according to the saturation current of the coil when the air gap is not increased includes: According to the formula B _m = μ ₀ μ _Fe H _m and μ _r = μ ₀ μ _Fe to obtain the relative magnetic permeability of the coil; According to the formula And B _m =μ ₀ μ _Fe H _Fe =μ ₀ μ _δ H _δ obtains the saturation current of the coil when increasing the air gap; wherein, _Im is the saturation current of the coil when the air gap is increased; B _m is the saturation magnetic induction; H _m is the total magnetic field strength; H _δ is the magnetic field strength of the air gap; H _Fe is the magnetic field strength of the iron material; l _δ is the length of the coil air gap; l _Fe is the _length of the iron core magnetic circuit; The saturation current of the coil when increasing the air gap; N ₁ is the primary side coil turns of the coil; μ _Fe is the magnetic permeability of the iron material; μ _r is the relative magnetic permeability of the coil, and μ ₀ is the vacuum magnetic permeability; μ _δ is the relative magnetic permeability of air, According to the input current, the cut-off current and the saturation current of the coil when the air gap is increased, the step of obtaining the relationship between the voltage change on the secondary side of the coil after the coil air gap is increased relative to the coil air gap for increasing the coil air gap is specifically as follows; According to the formula Get the coil secondary side voltage saturation value when increasing the air gap; When the input current is less than the cut-off current, according to the formula $\mathrm{\&Delta;\; U}=4.44f{N}_2{\mathrm{\&mu;}}_0\mathrm{Si}\sqrt{2}\mathrm{\&lambda;}{N}_1(\frac{{\mathrm{\&mu;}}_{\mathrm{Fe}}}{l}-\frac{1}{l_{\mathrm{\&delta;}}})$ Get the voltage change value on the secondary side of the coil: When the input current is greater than or equal to the cut-off current and less than the saturation current of the coil when the air gap is increased, according to the formula $u<\mathrm{\&Delta;\; U}<4.44f{N}_2{\mathrm{\&mu;}}_0{\mathrm{Si}}_1\sqrt{2}\mathrm{\&lambda;}{N}_1(\frac{{\mathrm{\&mu;}}_{\mathrm{Fe}}}{l}-\frac{1}{l_{\mathrm{\&delta;}}})$ Get the voltage variation range of the secondary side of the coil; When the input current is greater than or equal to the saturation current of the coil when the air gap is increased, the voltage change value of the secondary side of the coil is obtained according to the formula ΔU=U; Among them, U=U ₀ -U ₂ ; U ₂ is the voltage saturation value of the secondary side of the coil when the air gap is increased; ΔU is the voltage change value of the secondary side of the coil; f is the current voltage frequency of the grid; N ₂ is the coil S is the cross-sectional area of the iron core; λ is the lamination coefficient of the iron core; I ₁ is the cut-off current; I is the input current; l is the total magnetic circuit length of the coil; U ₀ is the saturation value of secondary side voltage without air gap.