Receiving coil three-dimensional positioning method and system based on decoupling coil

Abstract

The invention relates to the technical field of inductive wireless power transmission, and provides a receiving coil three-dimensional positioning method and system based on a decoupling coil. In order to solve the problem that in the prior art, a passive pre-embedded receiving coil cannot realize high-precision three-dimensional positioning, the main scheme is that a transmitting coil and an auxiliary coil are designed to be decoupled, a mapping relation between mutual inductance and positions is established, and an intersection point meeting an actual measurement result is searched, so that the position of the receiving coil is obtained. In the invention, a primary side energy emission part comprises a direct current power supply, a high-frequency inverter circuit, an LCC compensation circuit and an emission coil; the secondary side energy pickup part comprises a receiving coil, an S-shaped compensating circuit, a rectifying and filtering circuit and a resistive load; the primary side auxiliary positioning part comprises two open circuit solenoid coils which are perpendicularly orthogonal to the transmitting coil, and the primary side auxiliary positioning part, the transmitting coil and the open circuit solenoid coils are decoupled and only coupled with the receiving coil. The spatial position of the receiving coil can be accurately identified under the condition of horizontal rotation, and an auxiliary power supply and a control module are not needed.

Description

Technical Field

[0001] The present invention relates to the technical field of inductive wireless power transmission, and provides a three-dimensional positioning method and system for a receiving coil based on a decoupling coil. Background Art

[0002] Pre-embedded sensors can obtain key information such as internal stress, displacement, temperature and humidity of the structure in real time, providing important data support for disaster monitoring / early warning, and are the core components of the structural health monitoring system. However, the problem of sensor power endurance has always been a key technical bottleneck limiting its widespread application. In recent years, wireless power transmission technology has developed rapidly, providing an effective solution for powering pre-embedded sensors. In the wireless power supply system for pre-embedded sensors, the transmitting coil is located outside the structure, and the receiving coil and sensor are embedded inside the structure. The output power and efficiency of the system are highly dependent on the position alignment of the transmitting coil and the receiving coil. Therefore, the development of high-precision positioning technology suitable for pre-embedded receiving coils has become a key issue that needs to be urgently addressed in this field.

[0003] Existing positioning technologies mainly focus on locating transmitting coils, including magnetic signal detection and electrical signal detection. Magnetic signal detection obtains the coil position by combining the detection results of the Hall sensor and the Biot-Savart law. This technology requires an auxiliary DC power supply at the primary level. Electrical signal detection achieves positioning by establishing a voltage-position mapping database or analyzing the electromagnetic coupling coefficient, which requires control to achieve multi-modal switching. In addition, it is worth noting that the above method is only applicable to locating transmitting coils that are directly powered by a power supply, and is not applicable to the positioning of passive pre-embedded receiving coils. Therefore, the present invention proposes a three-dimensional positioning technology for pre-embedded receiving coils. Summary of the Invention

[0004] The present invention aims to solve the problem in the prior art that passive pre-buried receiving coils cannot achieve high-precision three-dimensional positioning. By introducing two auxiliary solenoid coils that are spatially perpendicular to the transmitting coil and decoupled in the magnetic field, the relative spatial position of the receiving coil and the transmitting coil can be accurately calculated based on mutual inductance voltage polarity determination and a three-dimensional mutual inductance-position mapping database, without the need for an external power supply or control module.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical means:

[0006] The present invention provides a three-dimensional positioning method for a receiving coil based on a decoupling coil, comprising the following steps:

[0007] Step (a): Set up the transmitting coil L p and two auxiliary coils L that are perpendicular to each other and magnetically decoupled from the transmitting coil x , auxiliary coil L y , forming a three-coil orthogonal decoupling structure;

[0008] Step (b): By measuring the voltage U of the transmitting coil L1 And the voltage U of the auxiliary coil x 、U y , calculate the transmitting coil L respectively p With the receiving coil L s Mutual inductance value M ps , auxiliary coil L x Mutual inductance value M with the receiving coil x , auxiliary coil L y Mutual inductance value M with the receiving coil y ;

[0009] Step (c): According to M x and M y The polarity of M determines the offset direction of the receiving coil relative to the main transmitting coil in the x-axis and y-axis directions, and based on x and M y The absolute value of is used to solve the possible position points of the receiving coil;

[0010] Step (d): According to the possible position points corresponding to M ps The monotonicity of determines the final positioning result of the receiving coil;

[0011] In the above solution, the calculation of the mutual inductance value in step (b) is based on the following relationship:

[0012]

[0013] Where V in is the DC input voltage, R L is the equivalent load resistance at the receiving end, ω is the angular frequency, and C1 is the series resonant capacitor of the LCC compensation network at the transmitting side.

[0014] In the above scheme, the step (c) further comprises:

[0015] When M x When it is positive, it is determined that the receiving coil is offset in the positive direction along the x-axis, otherwise it is offset in the negative direction along the x-axis;

[0016] When M y When it is positive, it is determined that the receiving coil is offset in the positive direction along the y-axis, otherwise it is offset in the negative direction along the y-axis;

[0017] According to M x and M y The absolute value of determines the possible position of the receiving coil.

[0018] In the above scheme, in step (d), M ps The monotonicity of M is as follows: ps It decreases monotonically as the offset distance of the receiving coil along the x-axis increases.

[0019] The above solution further includes the step of constructing a three-dimensional mutual induction-position database:

[0020] Obtain M at different spatial positions through finite element simulation or experiment ps 、M x 、M y value;

[0021] M x 、M y 、M ps It is associated with the xoy plane position to form a three-dimensional changing surface.

[0022] In the above solution, the operation of solving the possible position points of the receiving coil in step (c) is specifically as follows:

[0023] Combining the mutual inductance three-dimensional changing surface with the measured M x 、M y Two intersection lines are obtained, and the intersection point of the two intersection lines is the possible position point of the receiving coil.

[0024] In the above solution, the transmitting coil L p is a planar square coil, the receiving coil L s is a planar circular coil, and the two are arranged in parallel; the auxiliary coil L x 、L y It is a solenoid structure, orthogonally wound on the side wall of the ferrite core and magnetically decoupled from the main transmitting coil.

[0025] The present invention also provides an embedded receiving coil three-dimensional positioning system based on a decoupling coil, comprising:

[0026] The transmitting coil Lp is connected to the DC voltage source Vin, the inverter and the LCC compensation circuit;

[0027] Auxiliary coil L x and auxiliary coil L y They are orthogonally arranged in a vertical direction of the plane where the transmitting coil is located and are decoupled from each other;

[0028] The receiving coil Ls is connected to the secondary side S-type compensation circuit and rectifier;

[0029] Processing module, used to measure the transmitting coil inductance voltage U L1 , the first auxiliary coil induced voltage U x and the second auxiliary coil induced voltage U y , and calculate the mutual inductance based on the following formula:

[0030]

[0031] Determine the spatial coordinates of the receiving coil by comparing it with a pre-stored three-dimensional position-mutual inductance database;

[0032] Where V in is the input voltage, R L is the equivalent load resistance at the receiving end, ω is the angular frequency, C1 is the series resonant capacitor of the LCC compensation network at the transmitting side, and the transmitting coil L p With the receiving coil L s The mutual inductance is M ps , solenoid coil L x With the receiving coil L s The mutual inductance is M x , solenoid coil L y With the receiving coil L s The mutual inductance is M y .

[0033] In the above scheme, the auxiliary coil L x and auxiliary coil L y The two open-circuit solenoid coils are arranged orthogonally. The solenoid coils are connected to the transmitting coil L p The three are vertically orthogonal and decoupled from each other, and only the receiving coil L s There is coupling, and the system resonant angular frequency ω satisfies:

[0034]

[0035] Where j is the imaginary unit, C p is the parallel resonant capacitor in the LCC compensation circuit, C s L1 is the compensation inductor of the primary circuit at the transmitting end.

[0036] The three-dimensional positioning method and system for receiving coils based on decoupling coils provided by the present invention have the following significant advantages over the existing technology:

[0037] 1. High-precision three-dimensional positioning capability

[0038] By introducing the mutual decoupling auxiliary coil (L x 、L y ) and the transmitting coil (L p ) forms a three-coil orthogonal structure, combined with the mutual inductance voltage polarity determination and the three-dimensional mutual inductance-position mapping database, it can accurately solve the receiving coil (L s ) achieves millimeter-level positioning accuracy in the offset direction and distance of the x, y, and z axes, solving the problem of being unable to locate passive pre-buried receiving coils with high precision.

[0039] 2. No need for external power supply and control module

[0040] Energy transmission and positioning are carried out simultaneously, the transmitting coil (Lp ) excites the alternating magnetic field in the receiving coil (L s ) generates an induced voltage, eliminating the need for a power supply for the receiving coil; two auxiliary coils (L x 、L y ) do not interfere with each other, and their induced voltages can be detected synchronously without controlling the on / off of the coils, thus reducing system complexity and hardware costs.

[0041] 3. Applicable to horizontal rotation

[0042] The receiving coil adopts a centrosymmetric circular design, and the intersection point is solved by fitting the mutual inductance surface to locate the receiving coil, which ensures the effectiveness of the method in the case of horizontal rotation.

[0043] In summary, the present invention has achieved breakthrough progress in passive positioning accuracy, system complexity, cost control and positioning applicability, and provides technical support for the positioning of receiving coils in wireless power supply systems for embedded sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 :The system topology proposed by the present invention includes a voltage source V in , four controllable switch tubes Q1~Q4, composed of L1, C1 and C p The primary side LCC compensation circuit is composed of the secondary side compensation capacitor C s , the rectifier composed of D1 ~ D4, while introducing two open circuit auxiliary coils L x and L y .

[0045] Figure 2 : is a schematic diagram of the coupling structure proposed by the present invention, such as Figure 2 The receiving coil (L s ) is a planar circular coil, and is connected to the transmitting coil (L p ) are arranged in parallel; the transmitting coil (L p ) is a flat square coil placed under the ferrite core; the solenoid coil (L x 、L y ) are orthogonally wound around the side wall of the ferrite core, and the mutual inductance between the two is approximately zero, Figure 2 (b) shows the size information. Figure 2 Explanation of the reference numerals: 1-receiving coil, 2-solenoid coil L y , 3-solenoid coil L x , 4-transmitting coil, 5-magnetic core;

[0046] Figure 3 :Shows M ps 、M x and M ySimulation results of various offsets over a 60mm transmission distance. Figure 3 (a) shows M ps Surface and M with the change of offset ps =0 plane, from (a), when the X-axis and Y-axis offset range is -100mm to 100mm, M ps Keep positive value; From (b), we can see that when the X-axis offset is positive, M x is a positive value. When the X-axis offset is a negative value, M x is a negative value; from (c), when the Y-axis offset is positive, M y is a positive value. When the Y-axis offset is a negative value, M y is a negative value. Therefore, according to M x and M y The positive or negative value of is used to infer the direction of the embedded coil. Figure 3 M shown in (b) x Simulation results fitting surface and M x =5 The intersection of the planes can produce a curve, such as Figure 3 M shown in (c) y Simulation results fitting surface and M y =5The planes intersect to form another curve.

[0047] Figure 4 :Calculate the real-time mutual inductance result (M) by measuring the voltage x ′ and M y ′), respectively, M x =M x ' plane, M y =M y The ' plane intersects the mutual inductance simulation surface at a certain transmission distance, yielding two intersection lines. The intersection of these two lines represents the possible locations for that transmission distance. Points A and B correspond to the possible locations of the embedded coil at an 80mm transmission distance, while points A' and B' correspond to the possible locations at a 60mm transmission distance.

[0048] Figure 5 :Describes M ps With the change of X-axis offset. Figure 5 As shown, M ps As the X-axis offset increases, it decreases monotonically. Therefore, the only X-axis offset can be calculated based on the real-time M ps Finally, the exact position of the embedded receiving coil can be determined. Figure 5 If the measured M ps is 12.3μH, the final positioning result is point A′. DETAILED DESCRIPTION

[0049] The following is a detailed description of the embodiments of the present invention. Although the present invention will be described and illustrated in conjunction with certain specific embodiments, it should be noted that the present invention is not limited to these embodiments. On the contrary, modifications or equivalent substitutions of the present invention are intended to fall within the scope of the claims of the present invention.

[0050] In addition, in order to better illustrate the present invention, numerous specific details are given in the following detailed description. It will be understood by those skilled in the art that the present invention can also be implemented without these specific details.

[0051] In order to achieve accurate three-dimensional positioning, two mutually perpendicular open-circuit auxiliary coils are introduced to achieve the purpose of coil positioning. The present invention provides the following technical solutions: Clearly define the mutual inductance M ps The corresponding relationship with the current i1 is one-to-one, and we can further get U L1 Mutual inductance M ps One-to-one correspondence, by measuring U L1 To determine M ps , which simplifies the measurement of mutual inductance. Similarly, the voltage U x with U y To simplify the measurement of mutual inductance M x and M y .Depend on and Available, when M ps When i1 and i s In this case, according to U L1 =jωL1i1 and U x =jωM x i s , get U x and U L1 The polarity relationship between M x The sign of M is determined by: x is positive, then U x and U L1 have the same polarity, and if M x is negative, they exhibit opposite polarity. Similarly, M y The sign of U y and U L1 Polarity relationship between: When M y When U y and U L1 have the same polarity, but when M y When M is negative, their polarity is opposite. x The sign of U can be compared x and U L1 The polarity is determined by M y The symbol can be obtained from Uy and U L1 The polarity can be inferred.

[0052] Auxiliary coil L x Determine the relative position of the receiving coil and the transmitting coil in the x direction, auxiliary coil L y Determine the relative position of the receiving coil and the transmitting coil in the y direction. Through simulation and experiment, it can be obtained that when the coil is offset along the positive direction of the x-axis, the mutual inductance M x is positive, U x is also positive; when the coil is offset along the negative direction of the x-axis, the mutual inductance M x is negative, U x Also negative; M x The absolute value increases first and then decreases as the offset increases. Similarly, when the coil is offset along the positive direction of the y-axis, the mutual inductance M y is positive, U y is also positive; when the coil phase is offset along the negative direction of the y-axis, the mutual inductance M y is negative, U y Also negative; M y The absolute value increases first and then decreases as the offset increases. In summary, under the condition of known transmission distance, according to the unique M x A range of relative positions of a ring can be found, based on the unique M y Another circular relative position range can be found, and the two ranges can be intersected in space to obtain two relative position points, which are the possible position points of the receiving coil at the transmission distance.

[0053] Through the mutual inductance M between the transmitting coil and the receiving coil ps To determine the final positioning result. Figure 5 , the greater the offset along the X axis, the greater the mutual inductance M ps Therefore, when determining a mutual inductance M ps The value of has a unique X-axis offset corresponding to it, and a unique positioning result can be obtained.

[0054] Example 1

[0055] like Figure 1 A three-dimensional positioning system of an embedded receiving coil based on a decoupling coil is shown, comprising:

[0056] Primary energy transmission module, including DC power supply V in , full-bridge inverter circuit, LCC compensation circuit and transmitting coil L p The full-bridge inverter circuit is composed of four MOS tubes (Q1 to Q4), and the LCC compensation circuit includes a compensation inductor L1 and two compensation capacitors C1 and C p ;

[0057] Secondary side energy pickup module, including receiving coil L s , S-type compensation capacitor C s , full-bridge rectifier circuit and load R L The full-bridge rectifier circuit consists of four diodes (D1 to D4) and a filter capacitor C o constitute;

[0058] The primary side auxiliary positioning module includes two orthogonally arranged open circuit solenoid coils L x 、L y , the solenoid coil L x 、L y With the transmitting coil L p The three are vertically orthogonal, and are decoupled from each other, and only the receiving coil L s There is coupling; where the transmitting coil L is defined p With the receiving coil L s The mutual inductance is M ps , solenoid coil L x With the receiving coil L s The mutual inductance is M x , solenoid coil L y With the receiving coil L s The mutual inductance is M y .

[0059] The DC power supply is connected in sequence to the full-bridge inverter circuit, compensation circuit, transmitting coil L p The full-bridge inverter circuit is used to convert the DC voltage into a high-frequency AC square wave voltage, and the compensation circuit is used to filter out harmonics and shape the square wave voltage into a sinusoidal AC voltage, thereby generating a high-frequency AC voltage at the transmitting coil L. p The upper excitation produces an alternating magnetic field; the receiving coil L s With the transmitting coil L p Mutually coupled, connect compensation capacitors C in turn s and a full-bridge rectifier circuit, wherein the full-bridge rectifier circuit is used to convert AC into DC and achieve smooth filtering of the output voltage.

[0060] Furthermore, the system topology is determined as Figure 1 As shown, in order to make the current on the transmitting coil constant, the LCC-S compensation topology is used, and two auxiliary open-circuit coils are added on the basis of this topology. The KVL in the topology is written as follows

[0061]

[0062] In the formula

[0063]

[0064] where R acIt represents the resistance equivalent to the AC side of the load and the rectifier (composed of diodes D1 to D4);

[0065] From the above formula, we can deduce

[0066]

[0067] The relationship between different mutual inductance and voltage is further obtained as follows:

[0068]

[0069] Among them U in Indicates DC input voltage, U L1 is the voltage on the inductor L1, U x Indicates auxiliary coil L x Induced voltage value, U y Indicates auxiliary coil L y The induced voltage value.

[0070] When M ps When it is positive, i1 and i in the topology s In phase, U x With μ L1 The polarity relationship is only related to M x The sign of U y with U L1 The polarity relationship is only related to M y The symbol is related.

[0071] From this we can get:

[0072]

[0073] According to the above formula, the corresponding mutual inductance value can be obtained by measuring three different voltage values.

[0074] like Figure 2 As shown, the coupling structure consists of a transmitting coil, a receiving coil and two auxiliary coils, where the measured mutual inductance M ps 、M x and M y By measuring the voltage U L1 、U x and U y By establishing a finite element simulation model, the three-dimensional position coordinates and mutual inductance simulation value (M ps 、M x and M y ) of the corresponding database, the surface of the change of mutual inductance with position is as follows Figure 3 shown.

[0075] The real-time voltage U is measured during the measurement L1 ′、U x′ and U y ′, through the formula:

[0076]

[0077] The measured mutual inductance value M at the current moment can be calculated ps ′、M x ′ and M y ′.

[0078] Select the transmission distance and build the mutual inductance M x and M y Regarding the three-dimensional variation surface of the offset, find M x Surface and M x =M′ x The intersection of the planes, M y Surface and M y =M′ y The intersection of the two planes is obtained, and the intersection points A and B of the two intersection lines are obtained, which are the possible locations of the plane. Similarly, by changing the transmission distance, two more linear ranges are obtained by searching the database. The intersection of these two new linear ranges is obtained as the intersection points A' and B'. Repeat the above process to obtain multiple sets of possible locations of candidate planes.

[0079] In the candidate location point set, establish M ps A monotonic function about the X-axis offset is selected to satisfy M ps =M ps The point is taken as the final positioning result of the receiving coil.

Claims

1. A three-dimensional positioning method for receiving coils based on decoupling coils, characterized in that: The following steps are involved: Step (a): Set up the transmitting coil L p and two auxiliary coils L that are perpendicular to each other and magnetically decoupled from the transmitting coil x , auxiliary coil L y , forming a three-coil orthogonal decoupling structure; Step (b): By measuring the voltage U of the transmitting coil L1 And the voltage U of the auxiliary coil x 、U y , calculate the transmitting coil L respectively p With the receiving coil L s Mutual inductance value M ps , auxiliary coil L x Mutual inductance value M with the receiving coil x , auxiliary coil L y Mutual inductance value M with the receiving coil y ; Step (c): According to M x and M y The polarity of M determines the offset direction of the receiving coil relative to the main transmitting coil in the x-axis and y-axis directions, and based on x and M y The absolute value of is used to solve the possible position points of the receiving coil; Step (d): According to the possible position points corresponding to M ps The monotonicity of determines the final positioning result of the receiving coil.

2. The method according to claim 1, characterized in that The calculation of the mutual inductance value in step (b) is based on the following relationship: Where V in is the DC input voltage, R L is the equivalent load resistance at the receiving end, ω is the angular frequency, and C1 is the series resonant capacitor of the LCC compensation network at the transmitting side.

3. The method according to claim 1, characterized in that The step (c) further comprises: When M x When it is positive, it is determined that the receiving coil is offset in the positive direction along the x-axis, otherwise it is offset in the negative direction along the x-axis; When M y When it is positive, it is determined that the receiving coil is offset in the positive direction along the y-axis, otherwise it is offset in the negative direction along the y-axis; According to M x and M y The absolute value of determines the possible position of the receiving coil.

4. The method according to claim 1, wherein In the step (d), M ps The monotonicity of M is as follows: ps It decreases monotonically as the offset distance of the receiving coil along the x-axis increases.

5. The method according to claim 1, wherein It also includes the steps of constructing a three-dimensional mutual induction-position database: Obtain M at different spatial positions through finite element simulation or experiment ps 、M x 、M y value; M s 、M y 、M ps It is associated with the xoy plane position to form a three-dimensional changing surface.

6. The method according to claim 5, characterized in that The operation of solving the possible position points of the receiving coil in step (c) is specifically as follows: Combining the mutual inductance three-dimensional changing surface with the measured M x 、M y Two intersection lines are obtained, and the intersection point of the two intersection lines is the possible position point of the receiving coil.

7. The method according to claim 1, characterized in that The transmitting coil L p is a planar square coil, the receiving coil L s is a planar circular coil, and the two are arranged in parallel; the auxiliary coil L x 、L y It is a solenoid structure, orthogonally wound on the side wall of the ferrite core and magnetically decoupled from the main transmitting coil.

8. An embedded receiving coil three-dimensional positioning system based on a decoupling coil, characterized in that: include: The transmitting coil Lp is connected to the DC voltage source Vin, the inverter and the LCC compensation circuit; Auxiliary coil L x and auxiliary coil L y They are orthogonally arranged in a vertical direction of the plane where the transmitting coil is located and are decoupled from each other; The receiving coil Ls is connected to the secondary side S-type compensation circuit and rectifier; Processing module, used to measure the transmitting coil inductance voltage U L1 , the first auxiliary coil induced voltage U x The mutual inductance is calculated based on the following formula: Determine the spatial coordinates of the receiving coil by comparing it with a pre-stored three-dimensional position-mutual inductance database; Where V in is the input voltage, R L is the equivalent load resistance at the receiving end, ω is the angular frequency, C1 is the series resonant capacitor of the LCC compensation network at the transmitting side, and the transmitting coil L p With the receiving coil L s The mutual inductance is M ps , solenoid coil L x With the receiving coil L s The mutual inductance is M x , solenoid coil L y With the receiving coil L s The mutual inductance is M y .

9. The embedded receiving coil three-dimensional positioning system based on decoupling coils according to claim 8, characterized in that: Auxiliary coil L x and auxiliary coil L y The two open-circuit solenoid coils are arranged orthogonally. The solenoid coils are connected to the transmitting coil L p The three are vertically orthogonal and decoupled from each other, and only the receiving coil L s There is coupling, and the system resonant angular frequency ω satisfies: Where j is the imaginary unit, C p is the parallel resonant capacitor in the LCC compensation circuit, C s L1 is the compensation inductor of the primary circuit at the transmitting end.

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