Wide-range positioning detection system and method based on gradient combined differential coil

Abstract

The invention discloses a wide-range positioning detection system and a wide-range positioning detection method based on gradient combined differential coils, which are used for detecting mutual inductance M of primary and secondary sides of a power transmission system and are used for coil position adjustment and power control requirements, so that efficient and stable power transmission of the primary side is realized. According to the invention, through gradient combination of the differential coil cluster and mutual inductance decoupling of the primary side transmitting coil, coil mutual inductance detection in a wide horizontal and wide vertical range is realized through gradient combination, and through positioning and coil position adjustment of the secondary side coil cluster, the dynamic adjustment capability of the coil in the wide horizontal and wide vertical range is realized. The method is wide in applicability and can be applied to various wireless power transmission systems in vertical central symmetry.

Description

Technical Field

[0001] The present invention belongs to the technical fields of power electronics, wireless energy transmission and mutual inductance sensors, and in particular relates to a wide-range positioning detection system and method based on a gradient combined differential coil. Background Art

[0002] With the rapid development of science and technology, the demand for electricity in underwater, mine, and outdoor environments has increased dramatically. Wireless power transmission technology, with its non-contact energy transmission characteristics, can achieve non-exposed, unmanned power supply and mobile power supply, becoming a reliable energy supply solution in these special environments.

[0003] In practical applications, the mutual inductance of the wireless power transmission system will change with the three-dimensional movement of the device, which poses new challenges to the charging performance and control methods of the system. For example, patent CN 107490737 A "A method for estimating the load and mutual inductance of a wireless charging system" uses the voltage of the primary shunt capacitor and the moment value of the rising edge of the input current of the wireless energy transmission coil passing through zero within a cycle to replace the phase of each fundamental component for parameter estimation, and uses the functional relationship between the reflected complex impedance of the secondary circuit, the equivalent input complex impedance of the secondary compensation capacitor and the load to estimate the mutual inductance. However, this method cannot measure the mutual inductance before the main power circuit is started, and cannot be directly applied to other wireless power transmission topologies.

[0004] Another patent, CN 110103739A, "Weak Magnetic Field Excitation Three-Coil Detection Device", estimates the mutual inductance by applying an excitation current to the primary excitation coil and detecting the current of the primary and secondary coils when the secondary coil is open. This method requires obtaining the primary and secondary current information through communication means and measuring when the secondary coil is open, which may cause disturbances to power transmission.

[0005] In summary, wireless power transfer technology faces challenges brought by changes in mutual inductance in practical applications, and further research and development of new methods are needed to improve the charging performance and control accuracy of the system. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a wide-range positioning detection system and method based on a gradient combined differential coil. By utilizing a combined gradient differential coil cluster to form a coil sensor, the mutual inductance of the power coil is effectively measured within a wide horizontal and vertical range, providing important control and monitoring parameters for power transmission. The system has a simple structure and high reliability.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] Based on the gradient combined differential coil wide range positioning detection system, it is characterized by: including primary side and secondary side,

[0009] The primary side includes a transmitting coil L p Combined with the primary differential detection coil L dp , the primary side combined differential detection coil L dp It includes ferrite and a differential detection coil L located on the upper layer of the ferrite. dt and the differential detection coil L located under the ferrite db , the differential detection coil L dt and differential detection coil L db Symmetrical about the central axis of the ferrite, the transmitting coil L p Combined with the primary differential detection coil L dp About the transmitting coil L p The plane center axis is symmetrical, or position compensation is used to adjust the differential detection coil L db With the transmitting coil L p The primary differential mutual inductance M pd is zero;

[0010] The secondary side includes a receiving coil L s Combined with the secondary differential detection coil L ds , where power is transmitted by the transmitting coil L p And the receiving coil L s Mutual inductance M transmission of coupled power coils;

[0011] When the primary side sends power to the secondary side, the secondary side is connected by the receiving coil L s The power is absorbed by the transmitting coil L p And the receiving coil L s Mutual inductance M transmission of coupled power coils;

[0012] When the receiving coil L s and the ith combination of differential mutual inductance detection coil L di The secondary differential mutual inductance M sd When the differential value is constant at a certain height, N pairs of differential coils are used to form a gradient combination differential coil cluster to achieve the purpose of mutual inductance detection in a wide range;

[0013] The secondary side combined differential detection coil L ds Send weak power detection transmitting coil L p The position of the primary side combined differential detection coil L dp Position the secondary coil and adjust the position of the secondary coil by looking up the table so that the secondary coil is within the charging range.

[0014] As a preferred technical solution of the present invention: the differential detection coil L dt Including differential detection coil L d1t , Differential detection coil Ld2t And the differential detection coil L d3t , the differential detection coil L db Including differential detection coil L d1b , Differential detection coil L d2b And the differential detection coil L d3b .

[0015] As a preferred technical solution of the present invention: the transmitting coil L p and receiving coil L s It is set as a rectangular power coil or a circular power coil, and the primary side combined differential detection coil L dp Combined with the secondary differential detection coil L ds It is set as a circular differential coil or a rectangular differential coil, that is, including the following cases: when the transmitting coil L p and receiving coil L s When a circular power coil is set, the primary side combined differential detection coil L dp Combined with the secondary differential detection coil L ds Set as a circular differential coil; when the transmitting coil L p and receiving coil L s When set as a rectangular power coil, the primary side combined differential detection coil L dp Combined with the secondary differential detection coil L ds Set as a circular differential coil; when the transmitting coil L p and receiving coil L s When a circular power coil is set, the primary side combined differential detection coil L dp Set as a rectangular differential coil, the secondary side combined differential detection coil L ds Set as a circular differential coil; when the transmitting coil L p and receiving coil L s When set as a rectangular power coil, the primary side combined differential detection coil L dp Set as a rectangular differential coil, the secondary side combined differential detection coil L ds Set up as a circular differential coil.

[0016] As a preferred technical solution of the present invention: the combined differential mutual inductance detection coil L di Symmetrical about the central axis of the ferrite, and its radius is smaller than the transmitting coil L p With receiving coil L s Ten times the radius size.

[0017] As a preferred technical solution of the present invention: the combined differential mutual inductance detection coil L di Including the differential mutual inductance detection coil L located on the upper layer dit and the differential mutual inductance detection coil L located at the bottomdib , upper differential mutual inductance detection coil L dit Differential mutual inductance detection coil L dib The opposite ends are connected in series.

[0018] As a preferred technical solution of the present invention: in the receiving coil L s With the transmitting coil L p Maintain a fixed height h i When the upper differential mutual inductance detection coil L dit and the lower differential mutual inductance detection coil L dib With receiving coil L s Mutual inductance M dit With M dib The change trend of the two is the same, so that the difference M di Keep constant, when the i-th group of differential mutual inductance detection coil L di With receiving coil L s Mutual Inductance di When the secondary side differential detection coil L is kept constant, ds It can ensure that in N! kinds of permutations and combinations, mutual inductance measurement within a wide vertical range and horizontal range can be achieved.

[0019] As a preferred technical solution of the present invention: the transmitting coil L p With receiving coil L s It is a coil configuration symmetrically arranged perpendicular to the central axis, and the i-th group of differential coil clusters is also a coil configuration symmetrically arranged perpendicular to the central axis.

[0020] A wide range positioning detection method based on a gradient combined differential coil is characterized by comprising the following steps:

[0021] Step 1: Secondary side combined differential detection coil L ds First, combine the differential detection coil L to the primary side dp Send charging signal through the secondary side combined differential detection coil L ds The received signal strength is used to determine whether the charging requirements are met. Otherwise, the receiving coil L is adjusted by the table lookup method according to the mutual inductance detection result of the secondary detection coil. s Location;

[0022] Step 2: Combine the differential detection coil L according to the primary side dp The voltage V di , select the gradient combination type of the differential coil cluster;

[0023] Step 3: Primary side combined differential detection coil L dp Perform primary side mutual inductance detection, calculate mutual inductance M for power control, and send it to the transmitting coil L p Send charging instructions to charge;

[0024] Step 4: Secondary side combined differential detection coil L ds Received by the transmitting coil L p The power sent is repeated at different time intervals, and the operation of step 2 is repeated; if the charging conditions are not met in the above steps, the charging is terminated and returns to the first step to wait.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] Since the wireless energy transmission system is based on coil mutual inductance for energy transmission, the power coil mutual inductance can also be obtained with the help of coil sensors and used for the positioning and control of the charging process; in the present invention, by utilizing a gradient combined differential coil cluster and a coil cluster combination design, the mutual inductance detection requirements within a wide range of charging are met, the charging positioning and mutual inductance detection requirements are met, the stability and reliability of the charging process are improved, and important parameters for control and monitoring are provided for the wireless power control process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of a wireless power transmission system with a gradient combined differential coil cluster.

[0028] Figure 2 for Figure 1 Enlarged view of point a in the middle.

[0029] Figure 3 Schematic diagram of the circular power coil system architecture with a gradient-combined circular differential coil cluster.

[0030] Figure 4 Schematic diagram of the rectangular power coil system architecture with a gradient-combined circular differential coil cluster.

[0031] Figure 5 Schematic diagram of the circular power coil system architecture with a gradient-combined rectangular differential coil cluster.

[0032] Figure 6 Schematic diagram of the rectangular power coil system architecture with a gradient-combined rectangular differential coil cluster.

[0033] Figure 7 Schematic diagram of mutual inductance calculation between the i-th differential coil cluster and the power coil.

[0034] Figure 8 h i At high altitude, the differential coil detects the mutual inductance M di Target value curve.

[0035] Fig. 9 h i At height, the target differential coil detects the mutual inductance M di Decomposition of the synthetic curve.

[0036] Fig.10 Detecting mutual inductance M for differential coil cluster di A set of target value curves.

[0037] Fig.11 The flowchart is for coil positioning and calculating the mutual inductance M of the power coil using the differential coil cluster.

[0038] List of reference numerals:

[0039] 1. Ferrite; 2. Circular power coil; 3. Circular differential coil; 4. Rectangular power coil; 5. Rectangular differential coil. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0041] like Figure 1-2 As shown, the present invention proposes a wide range positioning detection system based on a gradient combined differential coil, including a primary side and a secondary side. The coil in the secondary side is used to detect the position of the coil in the primary side to determine whether the charging demand is met, and the detection coil in the primary side is used for mutual inductance detection and charging judgment.

[0042] The primary side includes a transmitting coil L p Combined with the primary differential detection coil L dp , the primary side combined differential detection coil L dp The invention comprises a ferrite 1 and a differential detection coil L located on the upper layer of the ferrite 1. dt and the differential detection coil L located under the ferrite 1 db , the differential detection coil L dt and differential detection coil L db Symmetrical about the central axis of the ferrite 1, the transmitting coil L p Combined with the primary differential detection coil L dp About the transmitting coil L p The plane center axis is symmetrical, or position compensation is used to adjust the differential detection coil L db With the transmitting coil L p The primary differential mutual inductance M pd is zero;

[0043] The secondary side includes a receiving coil L s Combined with the secondary differential detection coil L ds , where power is transmitted by the transmitting coil L p And the receiving coil L s Mutual inductance M transmission of coupled power coils;

[0044] When the primary side sends power to the secondary side, the secondary side is connected by the receiving coil Ls The power is absorbed by the transmitting coil L p And the receiving coil L s Mutual inductance M transmission of coupled power coils;

[0045] When the receiving coil L s and the ith combination of differential mutual inductance detection coil L di The secondary differential mutual inductance M sd When the differential value is constant at a certain height, N pairs of differential coils are used to form a gradient combination differential coil cluster to achieve the purpose of mutual inductance detection in a wide range;

[0046] The secondary side combined differential detection coil L ds Send weak power detection transmitting coil L p The position of the primary side combined differential detection coil L dp Position the secondary coil and adjust the position of the secondary coil by looking up the table so that the secondary coil is within the charging range.

[0047] The differential detection coil L dt Including differential detection coil L d1t , Differential detection coil L d2t And the differential detection coil L d3t , the differential detection coil L db Including differential detection coil L d1b , Differential detection coil L d2b And the differential detection coil L d3b .

[0048] The transmitting coil L p and receiving coil L s The primary side combined differential detection coil L is set to be rectangular or circular. dp Combined with the secondary differential detection coil L ds Set to be circular or rectangular, that is, including the following cases: when the transmitting coil L p and receiving coil L s When set as a circle, the primary side combined differential detection coil L dp Combined with the secondary differential detection coil L ds Set to a circular shape; when the transmitting coil L p and receiving coil L s When set to square, the primary side combined differential detection coil L dp Combined with the secondary differential detection coil L ds Set to a circular shape; when the transmitting coil L p and receiving coil L s When set as a circle, the primary side combined differential detection coil L dp The secondary side is configured as a square, and the differential detection coil Lds Set to a circular shape; when the transmitting coil L p and receiving coil L s When set to square, the primary side combined differential detection coil L dp The secondary side is configured as a square, and the differential detection coil L ds Set to circle.

[0049] The combined differential mutual inductance detection coil L di The ferrite 1 is symmetrical about the central axis, and its radius is smaller than the transmitting coil L. p With receiving coil L s Ten times the radius size.

[0050] The combined differential mutual inductance detection coil L di Including the differential mutual inductance detection coil L located on the upper layer dit and the differential mutual inductance detection coil L located at the bottom dib , upper differential mutual inductance detection coil L dit Differential mutual inductance detection coil L dib The opposite ends are connected in series.

[0051] In the receiving coil L s With the transmitting coil L p Maintain a fixed height h i When the upper differential mutual inductance detection coil L dit and the lower differential mutual inductance detection coil L dib With receiving coil L s Mutual inductance M dit With M dib The change trend of the two is the same, so that the difference M di Keep constant, when the i-th group of differential mutual inductance detection coil L di With receiving coil L s Mutual Inductance di When the secondary side differential detection coil L is kept constant, ds It can ensure that in N! kinds of permutations and combinations, mutual inductance measurement within a wide vertical range and horizontal range can be achieved.

[0052] The transmitting coil L p With receiving coil L s It is a coil configuration symmetrically arranged perpendicular to the central axis, and the i-th group of differential coil clusters is also a coil configuration symmetrically arranged perpendicular to the central axis.

[0053] like Figure 3-6 As shown, both the primary and secondary power coils and the gradient combined differential coils need to meet the coil combination type of vertical central axis symmetry, such as rectangular and circular; in fact, the primary and secondary coil combination can also be a combination of one circular and one square. Here, only four implementation examples are given, including the following cases: When the transmitting coil Lp and receiving coil L s When the circular power coil 2 is set, the primary side combined differential detection coil L dp Combined with the secondary differential detection coil L ds Set as a circular differential coil 3; when the transmitting coil L p and receiving coil L s When the rectangular power coil 4 is set, the primary side combined differential detection coil L dp Combined with the secondary differential detection coil L ds Set as a circular differential coil 3; when the transmitting coil L p and receiving coil L s When the circular power coil 2 is set, the primary side combined differential detection coil L dp It is set as a rectangular differential coil 5, and the secondary side combined differential detection coil L ds Set as a circular differential coil 3; when the transmitting coil L p and receiving coil L s When the rectangular power coil 4 is set, the primary side combined differential detection coil L dp It is set as a rectangular differential coil 5, and the secondary side combined differential detection coil L ds A circular differential coil 3 is provided.

[0054] like Figure 7 As shown in the figure, when the i-th group of gradient combined differential coils is added to the middle of the power coil, the primary transmitting coil L is first analyzed. p Combined differential mutual inductance detection coil L di Association: Since the differential coil is divided into the upper differential mutual inductance detection coil L dit and the lower differential mutual inductance detection coil L dib Two parts, with a ferrite 1 in the middle, and the primary transmitting coil L p Mutual inductance M with differential coil pdi It also consists of two parts, namely M pdit and M pdib .

[0055] When the transmitting coil L p Combined with the primary side differential detection coil L dp About the transmitting coil L p When the plane is symmetrical about the central axis, M pdit and M pdib equal, let the i-th group of differential mutual inductance detection coils L di The upper differential mutual inductance detection coil L dit Differential mutual inductance detection coil L dib When the opposite ends are connected in series,

[0056] M pdi =Mpdit -M pdib =0

[0057] In an asymmetric transmitting coil system, such as the transmitting coil L p In the case of ferrite 1, the position of the detection coil can be adjusted to eliminate the primary transmitting coil L p Mutual inductance M of differential mutual inductance detection coil pdi .

[0058] Similarly, with the help of the mutual inductance M between the primary side i-th differential coil and the transmitting coil pdi The analysis process of the secondary receiving coil L s With differential coil L di Relationship: Due to the mutual inductance M between the differential coil and the transmitting coil pdi is 0, and the receiving voltage V di Both come from the mutual inductance M between the receiving coil and the differential coil sdi When the opposite ends of the ith group of differential coils are connected, we have

[0059] M di =M sdi =M sdit -M sdib

[0060] According to the KVL equation, the mutual inductance M of the power coil satisfies the following conditions:

[0061]

[0062] According to the voltage on the detection coil comes from the receiving coil, we know that the mutual inductance M of the i-th group of differential coils and the transmitting coil pdi The following conditions are met:

[0063]

[0064] Therefore, the calculation expression of the mutual inductance of the power coil is:

[0065]

[0066] Coil input voltage V p And the differential coil induced voltage V di It can be collected through voltage sensors, so the calculation of mutual inductance M mainly depends on M di Identification of parameters.

[0067] like Figure 8 As shown, at different vertical heights H, M di The curves of the parameters changing with horizontal displacement are different, but the changing trends of the upper and lower differential coils are similar, such as Fig. 9 As shown. Therefore, at the design height h iThe appropriate differential coil can be designed to meet the differential mutual inductance M within a certain range. di Parameters (or M sdi parameters) remain constant.

[0068] like Fig.10 As shown, the detection mutual inductance M is kept constant within the horizontal displacement. di The charging area is defined as the effective charging range Ds. According to the SAEJ-2954 standard for electric vehicle charging, this range is usually 50% of the radius (side length) of the transmitting coil. Figure 1 and Figure 2 The 3-gradient combined differential coil cluster shown in Figure 1 can calculate the variation of mutual inductance M with horizontal displacement in 6 (3!) height intervals. And as the number of differential coils increases, the accuracy of the identifiable vertical height can be further improved.

[0069] The above analysis introduces the basic principle of calculating the mutual inductance of power coils using the gradient combined differential coil sensor. It is also necessary to use specific implementation cases to analyze the calculation steps of the power mutual inductance M.

[0070] like Fig.11 As shown, when the secondary side combination differential detection coil L at ② ds After sending the charging request command to the primary side, the receiving coil L at ② s A set of fixed amplitude detection signals is sent to the primary side, the mutual inductance is calculated by the detected reflected signal, and the position of the secondary coil is adjusted by the table lookup method to meet the charging posture requirements. After the primary side receives the charging instruction, the primary side combined differential detection coil L at ③ is set dp Detect the change of voltage. If it exceeds the judgment threshold, obtain the appropriate differential coil combination by scanning according to the voltage amplitude of the inspection coil (the judgment basis can be recorded in advance and judged by table lookup method). If it is within the detection range, mutual inductance detection can be performed and used for transmitting coil L at ①. p Power control and monitoring; After charging for a period of time, the transmitting coil L at ① p Insert a section of instruction and repeat the primary side combination differential detection coil L at ③ dp The mutual inductance detection process ensures that the coil does not move beyond the charging range during charging;

[0071] If according to the inspection ③ the primary side combined differential detection coil L dp If the coil voltage amplitude does not meet the corresponding detection interval, it indicates that there is a certain fault in the parking position of the receiving coil (such as horizontal parking, etc.), and the charging start instruction is returned to repeat the above process; wait for the secondary side receiving coil to calculate the mutual inductance through the secondary side detection coil cluster, which is used for the secondary side coil position adjustment to meet the charging position adjustment;

[0072] If the voltage change detected by the differential coil does not reach the charging threshold after the primary side receives the charging command, this indicates that the position of the receiving coil is not within the effective charging range, and it is necessary to return the charging start command and repeat the above process.

[0073] The wireless energy transmission system in this embodiment includes a power transmission coil and a gradient combined differential coil cluster. The differential association between the differential coil cluster and the power coil is used to calculate the power mutual inductance M within different horizontal displacement and vertical displacement ranges for secondary coil positioning and primary power transmission.

[0074] The wide range positioning detection method based on gradient combined differential coil includes the following steps:

[0075] Step 1: Secondary side combined differential detection coil L ds First, combine the differential detection coil L to the primary side dp Send charging signal through the secondary side combined differential detection coil L ds The received signal strength is used to determine whether the charging requirements are met. Otherwise, the receiving coil L is adjusted by the table lookup method according to the mutual inductance detection result of the secondary detection coil. s Location;

[0076] Step 2: Combine the differential detection coil L according to the primary side dp The voltage V di , select the gradient combination type of the differential coil cluster;

[0077] Step 3: Primary side combined differential detection coil L dp Perform primary side mutual inductance detection, calculate mutual inductance M for power control, and send it to the transmitting coil L p Send charging instructions to charge;

[0078] Step 4: Secondary side combined differential detection coil L ds Received by the transmitting coil L p The power sent is repeated at different time intervals, and the operation of step 2 is repeated; if the charging conditions are not met in the above steps, the charging is terminated and returns to the first step to wait.

[0079] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. Based on the gradient combined differential coil wide range positioning detection system, it is characterized by: Including the primary side and the secondary side, The primary side includes a transmitting coil L p Combined with primary differential detection coil L dp , the primary side combined differential detection coil L dp The invention comprises a ferrite (1) and a differential detection coil located on the upper layer of the ferrite (1). L dt and the differential detection coil located under the ferrite (1) L db , the differential detection coil L dt and differential detection coil L db The transmitting coil is symmetrical about the central axis of the ferrite (1). L p Combined with primary differential detection coil L dp About the Transmitter Coil L p The plane center axis is symmetrical, or position compensation is used to adjust the differential detection coil L db With the transmitting coil L p Primary differential mutual inductance M pd is zero; The secondary side includes a receiving coil L s Combined with the secondary side differential detection coil L ds , where power is transmitted by the transmitting coil L p And the receiving coil L s Coupled power coil mutual inductance M transmission; When the primary side sends power to the secondary side, the secondary side is connected by the receiving coil. L s Absorbs power, where power is transmitted by the transmitting coil L p And the receiving coil L s Coupled power coil mutual inductance M transmission; When the receiving coil L s and the ith combination of differential mutual inductance detection coils L di Secondary differential mutual inductance M sd When the differential value is constant at a certain height, N pairs of differential coils are used to form a gradient combination differential coil cluster to achieve the purpose of mutual inductance detection in a wide range; The secondary side combined differential detection coil L ds Send weak power detection transmitting coil L p Position, realize the primary side combined differential detection coil L dp Position the secondary coil and adjust the position of the secondary coil by looking up the table so that the secondary coil is within the charging range.

2. The wide range positioning detection system based on gradient combined differential coil according to claim 1 is characterized in that: The differential detection coil L dt Including differential detection coil L d1t , Differential detection coil L d2t And differential detection coil L d3t , the differential detection coil L db Including differential detection coil L d1b , Differential detection coil L d2b And differential detection coil L d3b .

3. The wide range positioning detection system based on gradient combined differential coil according to claim 1 is characterized in that: The transmitting coil L p and receiving coil L s It is configured as a rectangular power coil (4) or a circular power coil (2), wherein the primary side combined differential detection coil L dp Combined with the secondary side differential detection coil L ds The circular differential coil (3) or the rectangular differential coil (5) is configured, that is, the following situations are included: when the transmitting coil L p and receiving coil L s When a circular power coil (2) is used, the primary side combined differential detection coil L dp Combined with the secondary side differential detection coil L ds Set as a circular differential coil (3); when the transmitting coil L p and receiving coil L s When a rectangular power coil (4) is provided, the primary side combined differential detection coil L dp Combined with the secondary side differential detection coil L ds Set as a circular differential coil (3); when the transmitting coil L p and receiving coil L s When a circular power coil (2) is used, the primary side combined differential detection coil L dp It is set as a rectangular differential coil (5), the secondary side combined differential detection coil L ds Set as a circular differential coil (3); when the transmitting coil L p and receiving coil L s When a rectangular power coil (4) is provided, the primary side combined differential detection coil L dp It is set as a rectangular differential coil (5), the secondary side combined differential detection coil L ds It is arranged as a circular differential coil (3).

4. The wide range positioning detection system based on gradient combined differential coil according to claim 1 is characterized in that: The combined differential mutual inductance detection coil L di The ferrite (1) is symmetrical about its central axis and its radius is smaller than that of the transmitting coil. L p With receiving coil L s Ten times the radius size.

5. The wide range positioning detection system based on gradient combined differential coil according to claim 4 is characterized in that: The combined differential mutual inductance detection coil L di Including the differential mutual inductance detection coil located on the upper layer L dit and the differential mutual inductance detection coil located at the bottom L dib , upper differential mutual inductance detection coil L dit Differential mutual inductance detection coil L dib The opposite ends are connected in series.

6. The wide range positioning detection system based on gradient combined differential coil according to claim 4 is characterized in that: In the receiving coil L s With the transmitting coil L p Maintain a fixed height h i When the upper differential mutual inductance detection coil L dit and the differential mutual inductance detection coil at the lower layer L dib With receiving coil L s Mutual inductance M dit and M dib The change trend of M di Keep constant, when the i-th group of differential mutual inductance detection coil L di With receiving coil L s Mutual Induction M di When the secondary side is kept constant, the differential detection coil L ds It can ensure that in N! kinds of permutations and combinations, mutual inductance measurement within a wide vertical range and horizontal range can be achieved.

7. The wide range positioning detection system based on gradient combined differential coil according to claim 6 is characterized in that: The transmitting coil L p With receiving coil L s It is a coil configuration symmetrically arranged perpendicular to the central axis, and the i-th group of differential coil clusters is also a coil configuration symmetrically arranged perpendicular to the central axis.

8. The wide range positioning detection method based on gradient combined differential coil according to any one of claims 1 to 7, characterized in that: The steps include: Step 1: Secondary side combined differential detection coil L ds First, combine the differential detection coil to the primary side L dp Send charging signal through the secondary side combined differential detection coil L ds The received signal strength is used to determine whether the charging requirements are met. Otherwise, the receiving coil is adjusted by the table lookup method based on the mutual inductance detection result of the secondary detection coil. L s Location; Step 2: Combine the differential detection coil according to the primary side L dp Voltage on V di , select the gradient combination type of the differential coil cluster; Step 3: Primary side combined differential detection coil L dp Perform primary side mutual inductance detection and calculate mutual inductance M For power control and to the transmitting coil L p Send charging instructions to charge; Step 4: Secondary side combined differential detection coil L ds Receive the transmitting coil L p The power sent is repeated at different time intervals, and the operation of step 2 is repeated; if the charging conditions are not met in the above steps, the charging is terminated and returns to the first step to wait.

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