A method and model for decoupling coils based on current mode of butterfly coil

Abstract

The application discloses a method and a model construction method for coil decoupling based on butterfly coil current mode, which comprises the following steps: setting two butterfly coils as an initial overlapping state in which the middle conductors are collinear and partially coincide in the collinear direction; adjusting the relative spatial pose of the two coils and monitoring the resonant frequency of the coupling part in real time; when the common-mode resonant frequency and the differential-mode resonant frequency in the resonant frequency tend to be consistent, the current pose is determined as the target decoupling pose. The coupling problem of the butterfly coil array is solved, and no additional decoupling circuit is needed. Efficient decoupling can be realized only by pure structural adjustment, the channel isolation and parallel imaging performance are significantly improved while the near-field advantage of the butterfly coil is maintained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear magnetic resonance, and in particular to a coil decoupling method and model construction method based on butterfly coil current mode. BACKGROUND

[0002] In magnetic resonance imaging technology, in order to realize high signal-to-noise ratio imaging of a specific region, a surface receiving coil is often used. Among them, the butterfly coil can produce high signal-to-noise ratio and good spatial selectivity in the near-field region due to its unique left-right symmetrical loop structure, and has become an important coil form in high-resolution surface imaging. When multiple butterfly coil units are combined into an array to expand the coverage, suppressing electromagnetic coupling between units becomes a key to ensuring imaging performance.

[0003] To deal with the electromagnetic coupling problem in the butterfly coil array, related technologies usually adopt two ideas: one is to follow the geometric overlapping decoupling idea of traditional coils, that is, by mechanically adjusting the conductor overlapping area of two butterfly coils, trying to offset mutual inductance with spatial structure; the second is to introduce a compensation network at the circuit level, for example, adding capacitive or inductive elements between coil ports to neutralize the coupling effect.

[0004] However, the above scheme faces problems such as unstable decoupling effect and sensitivity to assembly tolerance in actual application, making it difficult to achieve reliable decoupling under various actual layout conditions. SUMMARY

[0005] The embodiment of the present application provides a coil decoupling method and model construction method based on butterfly coil current mode, which solves the bottleneck that the channel performance of the butterfly coil array is mutually restricted when the butterfly coil array is integrated at high density, so that the near-field high sensitivity advantage cannot be fully utilized, which seriously limits its application in fast high-resolution imaging. Through structure pose adjustment, efficient decoupling between coil units is realized without introducing any additional decoupling circuit, and the overall receiving performance and imaging quality of the coil array are improved.

[0006] The embodiment of the present application provides a coil decoupling method and model construction method based on butterfly coil current mode, which solves the bottleneck that the channel performance of the butterfly coil array is mutually restricted when the butterfly coil array is integrated at high density, so that the near-field high sensitivity advantage cannot be fully utilized, which seriously limits its application in fast high-resolution imaging. Through structure pose adjustment, efficient decoupling between coil units is realized without introducing any additional decoupling circuit, and the overall receiving performance and imaging quality of the coil array are improved.

[0007] The first butterfly coil and the second butterfly coil are set to an initial overlapping state;

[0008] Adjust the relative spatial pose of the first butterfly coil and the second butterfly coil;

[0009] During the adjustment process, the resonant frequency between the first butterfly coil and the second butterfly coil is obtained;

[0010] stop adjusting when a difference between the common mode resonance frequency and the differential mode resonance frequency in the resonance frequencies meets a preset condition, and determine the relative spatial pose at this time as a target decoupling pose;

[0011] wherein, at the time of stopping adjusting, there is a relative rotation angle or a relative translation amount between the two butterfly coils; and there is a projection offset amount between the projections of the middle conductors of the two butterfly coils in a plane perpendicular to the middle conductors of the two butterfly coils; a geometric state defined by at least one of the relative rotation angle, the relative translation amount and the projection offset amount constitutes a decoupling configuration.

[0012] Optionally, the step of adjusting the relative spatial pose of the first butterfly coil and the second butterfly coil comprises:

[0013] controlling the first butterfly coil and the second butterfly coil to generate a relative rotation; or

[0014] controlling the first butterfly coil and the second butterfly coil to generate a relative translation in a direction parallel to the plane of the coils.

[0015] Optionally, the step of controlling the first butterfly coil and the second butterfly coil to generate a relative rotation comprises:

[0016] controlling the first butterfly coil to be stationary and the second butterfly coil to rotate by a first angle about its own middle conductor axis; or

[0017] controlling the second butterfly coil to be stationary and the first butterfly coil to rotate by the first angle about its own middle conductor axis; or

[0018] controlling the first butterfly coil to rotate by a second angle about its own middle conductor axis and simultaneously controlling the second butterfly coil to rotate by a third angle about its own middle conductor axis.

[0019] Optionally, the step of controlling the first butterfly coil and the second butterfly coil to generate a relative translation in a direction parallel to the plane thereof comprises:

[0020] controlling the first butterfly coil to be stationary and the second butterfly coil to translate by a first distance in a direction parallel to the middle conductor; or

[0021] controlling the second butterfly coil to be stationary and the first butterfly coil to translate by the first distance in a direction parallel to the middle conductor; or

[0022] controlling the first butterfly coil and the second butterfly coil to translate in opposite directions or in the same direction in a direction parallel to the middle conductor of each, respectively.

[0023] Optionally, the step of obtaining the resonant frequency between the first butterfly coil and the second butterfly coil during the adjustment process comprises:

[0024] establishing an equivalent circuit model of electromagnetic coupling between the intermediate conductors of the first butterfly coil and the second butterfly coil at each adjusted pose;

[0025] extracting mutual inductance parameters between the two intermediate conductors from the equivalent circuit model;

[0026] calculating the resonant frequency under the common mode excitation condition and the differential mode excitation condition respectively based on the mutual inductance parameters, as the common mode resonant frequency and the differential mode resonant frequency.

[0027] Optionally, before the step of calculating the resonant frequency under the common mode excitation condition and the differential mode excitation condition, the method comprises:

[0028] applying excitation signals with the same phase to the first butterfly coil and the second butterfly coil to simulate the common mode excitation condition;

[0029] applying excitation signals with opposite phases to the first butterfly coil and the second butterfly coil to simulate the differential mode excitation condition.

[0030] Optionally, the step of determining the relative spatial pose at this time as the target decoupling pose when the difference between the common mode resonant frequency and the differential mode resonant frequency in the resonant frequency satisfies a preset condition comprises:

[0031] during the adjustment process, calculating the current actual difference between the common mode resonant frequency and the differential mode resonant frequency;

[0032] when the actual difference is less than or equal to a preset maximum difference, it is determined that the preset condition is satisfied, and the current relative spatial pose is determined as the target decoupling pose.

[0033] Optionally, the step of setting the first butterfly coil and the second butterfly coil to an initial overlapping state comprises:

[0034] aligning the intermediate conductors of the first butterfly coil and the intermediate conductors of the second butterfly coil in parallel;

[0035] moving the first butterfly coil or the second butterfly coil along the length direction of the intermediate conductors until the two intermediate conductors form an overlapping section in the length direction; wherein the length of the overlapping section is greater than zero and less than the full length of any intermediate conductor.

[0036] In addition, the embodiment of the present application also provides an experience model construction method for butterfly coil decoupling design, which applies the method as described above, comprising the following steps:

[0037] By executing the coil decoupling method based on the butterfly coil current mode, a plurality of sets of sample data are obtained; each set of sample data at least includes: a size parameter of a butterfly coil, a decoupling configuration parameter in a target decoupling pose, and a resonant frequency parameter corresponding to the decoupling configuration parameter;

[0038] Based on the plurality of sets of sample data, a structured data set is constructed, which establishes a mapping relationship between the size parameter, the decoupling configuration parameter and the resonant frequency parameter;

[0039] The size parameter of the butterfly coil is taken as an input feature, and the relative spatial pose parameter is taken as a prediction target, and a preset model is trained to generate an empirical model for predicting the decoupling configuration parameter of a butterfly coil of different sizes.

[0040] Optionally, the decoupling configuration parameter predicted by the empirical model is at least one of the following parameters of the decoupling configuration: relative rotation angle, relative translation amount or projection offset.

[0041] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0042] By utilizing the differential mode current characteristics inherent in the butterfly coil, rotation adjustment is introduced as a decoupling control means, and the complex electromagnetic coupling problem is converted into a geometric parameter problem that can be precisely controlled. By rotating to change the relative relationship between the common mode and differential mode resonant frequencies between coils, they are canceled out at a certain angle, thereby achieving active elimination of channel coupling without compromising the inherent high sensitivity of the coil; This structured decoupling method not only avoids the complexity and loss brought by the traditional circuit compensation scheme, but also establishes a closed-loop process of pose adjustment-frequency monitoring-parameter determination, so that the decoupling process is upgraded from empirical trial and error to quantifiable and repeatable standardized operation, and finally the butterfly coil array can maintain near-field signal-to-noise ratio and high channel independence in high-density compact layout. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a framework schematic diagram of the coil decoupling method based on the butterfly coil current mode of the present application;

[0044] Figure 2 It is a flowchart of the coil decoupling method based on the butterfly coil current mode of the present application;

[0045] Figure 3 It is a structural schematic diagram of the butterfly coil of the present application;

[0046] Figure 4 It is an example diagram of the initial overlapping state and the spatial pose adjustment of the butterfly coil pair of the present application;

[0047] Figure 5 A decoupling state of a butterfly coil array of the present application;

[0048] Figure 6 An example diagram of the present application for decoupling of a butterfly coil by translation;

[0049] Figure 7 A flowchart of the method for constructing an empirical model for the decoupling design of a butterfly coil of the present application;

[0050] Figure 8 A terminal structure schematic diagram related to the hardware running environment of an embodiment scheme of the present application. DETAILED DESCRIPTION

[0051] In view of the fundamental contradiction that the excellent near-field receiving performance and multi-channel signal independence of the butterfly coil array cannot be achieved simultaneously when pursuing high-density integration, a coil decoupling method based on the current mode of the butterfly coil is proposed. By adjusting the relative rotation angle between two butterfly coils, the electromagnetic mode distribution of the coupling region is changed, so that the difference between the common-mode resonance frequency and the differential-mode resonance frequency reaches a preset minimum value or zero value, thereby actively canceling the harmful coupling between channels from a physical principle without losing the single-channel signal-to-noise ratio. Through simple mechanical structure adjustment, efficient and stable decoupling is achieved, and finally the butterfly coil array can realize high sensitivity and high parallel imaging performance at the same time with a compact layout.

[0052] In order to better understand the above technical solutions, the exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0053] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the drawings in the specification and the specific embodiments.

[0054] Embodiment one;

[0055] In the present embodiment, a coil decoupling method based on the current mode of the butterfly coil is provided.

[0056] With reference to Figures 1-2 , the coil decoupling method based on the current mode of the butterfly coil of the present embodiment includes the following steps:

[0057] Step S1, set the first butterfly coil and the second butterfly coil to an initial overlapping state;

[0058] In this embodiment, as shown in Figure 3 , the butterfly coil is composed of two symmetric conductor loops connected by an intermediate conductor. The current mode of the butterfly coil is that the currents in the left and right loops are out of phase. For example, when the current in the left loop is clockwise, the current in the right loop is counterclockwise.

[0059] As an alternative embodiment, the intermediate conductor of the first butterfly coil is aligned parallel to the intermediate conductor of the second butterfly coil, and the first and second butterfly coils are moved along the length direction of the intermediate conductor until a overlapping section is formed in the length direction between the two intermediate conductors. The length of the overlapping section is greater than zero and less than the full length of any intermediate conductor. The length of the overlapping section can be flexibly set according to the actual array layout, the target coupling strength, and the subsequent decoupling adjustment space requirements.

[0060] Exemplarily, referring to Figure 4 part (a) and Figure 4 part (b) therein, they are respectively the initial arrangement states of the butterfly coil arrays in the common mode and differential mode. The overlapping part is within the dashed box.

[0061] It should be noted that the coil decoupling method of the present application can be applied not only to the butterfly coil structure, but also to any radio frequency resonator or antenna unit having similar electrical characteristics, that is, composed of two symmetric conductor loops and capable of using the differential mode current as the main working mode. The two symmetric conductor loops can be circular, rectangular, elliptical or other polygonal loops.

[0062] Optionally, the degree of overlap in the initial overlapping state can be determined by electrical measurement. Specifically, on the premise that the intermediate conductors of the two coils are aligned, the coils are moved closer to each other while monitoring the mutual inductance coefficient between the ports of the two coils. When the mutual inductance coefficient reaches the preset target value, the movement is stopped and the position is fixed. The state at this time is the required initial overlapping state. The preset target value can be obtained in advance through simulation or empirical formula according to the coil size and operating frequency. Associating the abstract geometric overlap with the key electrical parameters ensures that the initial state established each time has a consistent and strong electromagnetic coupling.

[0063] Optionally, the degree of overlap in the initial overlapping state can also be defined by geometric parameters. For example, for a butterfly coil with circular loops, it can be defined as: the distance d between the centers of the two circles satisfies 0 < d < 2r, where r is the radius of the loop, and the area of the overlapping region is greater than 0 at this time. The distance d between the centers of the circles can be preset as (0.5~1.5)×r to ensure a consistent initial coupling strength.

[0064] Step S2: Adjust the relative spatial pose of the first butterfly coil and the second butterfly coil;

[0065] In the embodiment, by changing the relative position or angle between the first butterfly coil and the second butterfly coil, the geometric relationship between the two can be controlled, and an operable physical variable is provided for subsequent electromagnetic monitoring to find the optimal decoupling point.

[0066] As an optional implementation, when adjusting the relative spatial pose of the two butterfly coils, the relative rotation of the two butterfly coils can be controlled.

[0067] For example, keep the first butterfly coil stationary and only control the second butterfly coil to rotate around the axis of the intermediate conductor by an angle . Record this angle as the relative rotation angle between the two coils. Or keep the second butterfly coil stationary and control the first butterfly coil to rotate around the axis of the intermediate conductor by an angle . Or control both coils to rotate simultaneously, such as Figure 5 , and the rotation angle is the relative rotation angle.

[0068] As another optional implementation, when adjusting the relative spatial pose of the two butterfly coils, the relative translation of the two butterfly coils in the direction parallel to their plane can also be controlled.

[0069] For example, place the two coils parallel in the same plane and keep the initial overlap. For example, Figure 6 , keep the first butterfly coil stationary and only control the second butterfly coil to translate along the axis of the intermediate conductor by a distance d, which is recorded as the relative translation. Or keep the second butterfly coil stationary and control the first butterfly coil to translate along the axis of the intermediate conductor. Or control the first butterfly coil to move in a first direction and the second butterfly coil to move in a direction opposite to the first direction.

[0070] Step S3, during the adjustment process, obtain the resonant frequency between the first butterfly coil and the second butterfly coil;

[0071] In the embodiment, during the adjustment process, the resonant frequency between the two coils at each pose is obtained, including the common-mode resonant frequency and the differential-mode resonant frequency.

[0072] As an optional implementation, at each adjusted pose, an equivalent circuit model of electromagnetic coupling between the intermediate conductors of the first butterfly coil and the second butterfly coil is established, the mutual inductance parameters between the two intermediate conductors are extracted from the equivalent circuit model, and based on the mutual inductance parameters, the resonant frequencies under common-mode excitation and differential-mode excitation are calculated respectively as the common-mode resonant frequency and the differential-mode resonant frequency.

[0073] Exemplarily, the monitoring step can be realized by establishing and analyzing an equivalent circuit model of the coupling coils, which is an abstract mathematical description of the distributed inductance, distributed capacitance inherent to the butterfly coils themselves and the mutual inductance between them resulting from spatial coupling, rather than adding actual electronic components. Specifically, the self-inductance parameters, capacitance parameters and mutual inductance parameters of the coils in a certain pose are obtained through electromagnetic simulation, measurement or theoretical calculation, and then the common-mode resonance frequency and the differential-mode resonance frequency in the pose are calculated, such as Figure 4 (c) and Figure 4 (d) in

[0074] It should be noted that the decoupling overlap region refers to the overlapping region formed by the conductor loops of the first butterfly coil and the second butterfly coil in the projection plane during the pose adjustment process, which is a sub-region between the two parallel and spatially separated intermediate conductors. This sub-region is the key to regulating electromagnetic coupling. When common-mode excitation, the currents in the two intermediate conductors are in the same direction, and the magnetic field interaction in this sub-region dominates the common-mode resonance frequency; when differential-mode excitation, the currents in the two intermediate conductors are in opposite directions, and the magnetic field interaction in this sub-region dominates the differential-mode resonance frequency.

[0075] Step S4, when the difference between the common-mode resonance frequency and the differential-mode resonance frequency in the resonance frequency meets the preset condition, stop adjusting, and determine the relative spatial pose at this time as the target decoupling pose.

[0076] In this embodiment, in the process of continuously adjusting the pose and synchronously monitoring the resonance frequency, the key indicator representing the coupling strength, the difference between the common-mode resonance frequency and the differential-mode resonance frequency, is calculated and judged in real time. When the difference meets the preset condition, stop the adjustment action, and mark and record the accurate relative position and angle of the coils at the current time as the final target decoupling pose.

[0077] As an optional implementation, in the monitoring process, the current actual difference between the common-mode resonance frequency and the differential-mode resonance frequency is calculated; when the actual difference is less than or equal to the preset maximum difference, it is determined that the preset condition is met, and the current relative spatial pose is determined as the target decoupling pose.

[0078] Exemplarily, in the adjustment process, the actual difference between the common-mode resonance frequency and the differential-mode resonance frequency in the current pose is calculated in real time. For example, when the rotation angle is adjusted to 10 degrees, the measured = 210.5 MHz, = 209.8 MHz, and the actual difference = 0.7 MHz; continue to fine-tune to 11 degrees, and the measured = 210.2 MHz, = 210.2 MHz, actual difference = 0.0 MHz. The preset maximum allowed difference threshold is set as = 0.5 MHz. When rotating to 11 degrees, calculating the instant = 0.0 MHz, immediately determine that the current actual difference (0.0 MHz) ≤ preset maximum difference (0.5 MHz), satisfy the decoupling completion condition, immediately stop pose adjustment, and the relative rotation angle of 11 degrees at this time and the corresponding spatial position are formally locked and recorded as the final target decoupling pose.

[0079] Optionally, when the adjustment is stopped, it is proved by experiments that when the two butterfly coils reach the decoupling state, the spatial geometric relationship thereof satisfies the following characteristics: there is a relative rotation angle or a relative translation amount between the two coils; and when projected on a reference plane perpendicular to the intermediate conductor, there is a projection offset amount between the projection lines of the two intermediate conductors. The decoupling state is a specific decoupling configuration defined by at least one of the relative rotation angle, the relative translation amount and the projection offset amount. The projection offset amount is the shortest vertical distance between the projection lines of the two intermediate conductors.

[0080] The technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

[0081] By actively regulating the electromagnetic coupling mode of the butterfly coil through structural pose adjustment, without any additional circuit, the problem of mutual restriction of unit performance in a high-density array is solved, and the unification of high near-field signal-to-noise ratio and high channel isolation is realized. The decoupling process is standardized and quantized, and the overall imaging performance and design efficiency of the array are significantly improved.

[0082] Based on the same inventive concept, the embodiment of the present application also provides an experience model construction method for butterfly coil decoupling design corresponding to the method in embodiment one, see embodiment two.

[0083] Embodiment two;

[0084] Based on embodiment one, another embodiment of the present application is proposed, referring to Figure 7 The experience model construction method for butterfly coil decoupling design comprises:

[0085] Step one, obtain a plurality of groups of sample data by executing a coil decoupling method based on a butterfly coil current mode; wherein each group of sample data at least comprises: size parameters of the butterfly coil, decoupling configuration parameters in a target decoupling pose, and resonant frequency parameters corresponding to the decoupling configuration parameters;

[0086] In this embodiment, during the adjustment of the pose, the change parameters of the relative spatial pose and the change data of the corresponding resonant frequency are recorded synchronously, and based on the recorded data, a data set reflecting the mapping relationship between the relative spatial pose parameters and the resonant frequency is generated. According to the data set, an empirical model for predicting the decoupling parameters of different size butterfly coil arrays is established.

[0087] As an optional implementation, a coil decoupling method of a butterfly coil current mode is performed to decouple and test butterfly coil pairs of multiple different size specifications. For each group of butterfly coils of a size, the final spatial configuration when the target decoupling state is reached is found by adjusting the relative pose, and relevant data is recorded.

[0088] Specifically, each group of sample data at least includes size parameters of the butterfly coil, decoupling configuration parameters in the target decoupling pose, and resonant frequency parameters corresponding to the decoupling configuration parameters. The size parameters of the butterfly coil include but are not limited to the length of the middle conductor, the expansion angle of the butterfly wing, the width of the wire, and the overall outer diameter of the coil, and other key dimensions. The decoupling configuration parameters are the relative rotation angle between the two coils, the relative translation amount, and the projection offset amount on the screen perpendicular to the middle conductor when the coil reaches the optimal decoupling state. The resonant frequency parameter records the main working resonant frequency or frequency band of the coil in the decoupling configuration, which is related to the electrical performance, and ensures that the configuration predicted by the final empirical model can meet the specific working frequency requirement.

[0089] Step two, based on the multiple groups of sample data, a structured data set is constructed to establish the mapping relationship between the size parameters, the decoupling configuration parameters, and the resonant frequency parameters;

[0090] In this embodiment, the obtained multiple groups of sample data are uniformly arranged, abnormal values are removed, and normalization or standardization preprocessing is performed to eliminate the dimension influence. Then a structured data set is constructed, and the core of the data set is to establish a clear mapping relationship from the input to the output.

[0091] Specifically, the input features are the size parameters of the butterfly coil, and the output target is the decoupling configuration parameters and the corresponding resonant frequency parameters required when the decoupling is reached. The data set essentially encodes the physical law of predicting the spatial pose required for the given coil size to reach the decoupling.

[0092] Step three, the size parameters of the butterfly coil are taken as the input features, and the relative spatial pose parameters are taken as the prediction target to train a preset model, and an empirical model for predicting the decoupling configuration parameters of different size butterfly coils is generated.

[0093] In this embodiment, based on the constructed data set, a machine learning model is trained.

[0094] As an optional implementation, the input features of the model are the size parameters of the butterfly coil, and the prediction target of the model is the decoupling configuration parameter. The resonance frequency parameter can be used as an auxiliary verification target or a multi-task learning target. The decoupling configuration parameter includes at least one of the relative rotation angle, the relative translation amount, and the projection offset amount.

[0095] The embodiment converts the decoupling design process into a quantifiable and predictable data-driven process by establishing a direct prediction model from the coil size to the decoupling configuration. After the coil size is determined, a high-precision decoupling configuration prediction result can be quickly obtained through the model, which improves the design efficiency, reduces the research and development cost and period, and forms a technical closed loop of “data accumulation-model optimization-design enhancement” through the reusability and continuous learning ability of the model.

[0096] Embodiment three;

[0097] In the embodiment of the present application, a coil decoupling device based on the current mode of the butterfly coil is proposed.

[0098] Referring to Figure 8 , Figure 8 The terminal structure diagram of the hardware running environment involved in an embodiment of the present application is shown.

[0099] As Figure 8 shown, the control terminal can include a processor 1001, such as a CPU, a network interface 1003, a memory 1004, and a communication bus 1002. The communication bus 1002 is used to realize the connection and communication between the components. The network interface 1003 can optionally include a standard wired interface, a wireless interface (such as a WI-FI interface). The memory 1004 can be a high-speed RAM memory or a stable memory (non-volatile memory), such as a magnetic disk memory. The memory 1004 can optionally be a storage device independent of the aforementioned processor 1001.

[0100] Those skilled in the art can understand Figure 8 that the terminal structure shown in the embodiment does not constitute a limitation on the terminal, and can include more or fewer components than the diagram, or combine certain components, or different component arrangements.

[0101] As Figure 8 shown, the memory 1004 as a computer storage medium can include an operating system, a network communication module, and a coil decoupling program based on the current mode of the butterfly coil.

[0102] In Figure 8In the illustrated coil decoupling device hardware structure based on the butterfly coil current mode, the processor 1001 can call the coil decoupling program based on the butterfly coil current mode stored in the memory 1004, and perform the following operations:

[0103] Set the first butterfly coil and the second butterfly coil to an initial overlapping state;

[0104] Adjust the relative spatial pose of the first butterfly coil and the second butterfly coil;

[0105] During the adjustment process, obtain the resonant frequency between the first butterfly coil and the second butterfly coil;

[0106] When the difference between the common-mode resonant frequency and the differential-mode resonant frequency in the resonant frequency satisfies a preset condition, stop adjusting, and determine the relative spatial pose at this time as the target decoupling pose.

[0107] Optionally, the processor 1001 can call the coil decoupling program based on the butterfly coil current mode stored in the memory 1004, and further perform the following operations:

[0108] Control the first butterfly coil and the second butterfly coil to produce relative rotation; or

[0109] Control the first butterfly coil and the second butterfly coil to produce relative translation in a direction parallel to the plane thereof.

[0110] Optionally, the processor 1001 can call the coil decoupling program based on the butterfly coil current mode stored in the memory 1004, and further perform the following operations:

[0111] Control the first butterfly coil to be stationary, and control the second butterfly coil to rotate by a first angle around its own middle conductor axis; or

[0112] Control the second butterfly coil to be stationary, and control the first butterfly coil to rotate by the first angle around its own middle conductor axis; or

[0113] Control the first butterfly coil to rotate by a second angle around its own middle conductor axis, and simultaneously control the second butterfly coil to rotate by a third angle around its own middle conductor axis.

[0114] Optionally, the processor 1001 can call the coil decoupling program based on the butterfly coil current mode stored in the memory 1004, and further perform the following operations:

[0115] Control the first butterfly coil to be stationary, and control the second butterfly coil to translate by a first distance along a direction parallel to the middle conductor; or

[0116] controlling the second butterfly coil to be stationary, and the first butterfly coil to translate in a direction parallel to the middle conductor by the first distance; or

[0117] controlling the first butterfly coil and the second butterfly coil to translate in opposite directions parallel to their respective middle conductors.

[0118] Optionally, the processor 1001 can invoke the coil decoupling program based on the butterfly coil current mode stored in the memory 1004, and further perform the following operations:

[0119] at each adjusted pose, establishing an equivalent circuit model of electromagnetic coupling between the middle conductors of the first butterfly coil and the second butterfly coil;

[0120] extracting mutual inductance parameters between the two middle conductors from the equivalent circuit model;

[0121] based on the mutual inductance parameters, calculating the resonant frequencies under the common mode excitation condition and the differential mode excitation condition, respectively, as the common mode resonant frequency and the differential mode resonant frequency.

[0122] Optionally, the processor 1001 can invoke the coil decoupling program based on the butterfly coil current mode stored in the memory 1004, and further perform the following operations:

[0123] applying excitation signals with the same phase to the first butterfly coil and the second butterfly coil to simulate the common mode excitation condition;

[0124] applying excitation signals with opposite phases to the first butterfly coil and the second butterfly coil to simulate the differential mode excitation condition.

[0125] Optionally, the processor 1001 can invoke the coil decoupling program based on the butterfly coil current mode stored in the memory 1004, and further perform the following operations:

[0126] during the adjustment process, calculating a current actual difference value of the common mode resonant frequency and the differential mode resonant frequency;

[0127] when the actual difference value is less than or equal to a preset maximum difference value, determining that the preset condition is satisfied, and determining the current relative spatial pose as the target decoupling pose.

[0128] Optionally, the processor 1001 can invoke the coil decoupling program based on the butterfly coil current mode stored in the memory 1004, and further perform the following operations:

[0129] aligning the middle conductor of the first butterfly coil and the middle conductor of the second butterfly coil in parallel;

[0130] The first butterfly coil or the second butterfly coil is moved along the length direction of the intermediate conductor until the two intermediate conductors form an overlapping section in the length direction; wherein the length of the overlapping section is greater than zero and less than the full length of any intermediate conductor.

[0131] In addition, in Figure 8 In the coil decoupling device hardware structure based on the butterfly coil current mode shown, the processor 1001 can call the experience model construction program for butterfly coil decoupling design stored in the memory 1004, and perform the following operations:

[0132] Through the above program, a plurality of groups of sample data are obtained; wherein each group of sample data at least includes: size parameters of a butterfly coil, decoupling configuration parameters in a target decoupling pose, and resonant frequency parameters corresponding to the decoupling configuration parameters;

[0133] Based on the plurality of groups of sample data, a structured data set is constructed, which establishes a mapping relationship between the size parameters, the decoupling configuration parameters and the resonant frequency parameters;

[0134] The size parameters of the butterfly coil are taken as input features, and the relative spatial pose parameters are taken as prediction targets, and a preset model is trained to generate an experience model for predicting decoupling configuration parameters of butterfly coils of different sizes.

[0135] Optionally, the processor 1001 can call the experience model construction program for butterfly coil decoupling design stored in the memory 1004, and further perform the following operations:

[0136] The decoupling configuration parameters predicted by the experience model are at least one of the following parameters of the decoupling configuration: relative rotation angle, relative translation amount or projection offset.

[0137] Those skilled in the art will appreciate that embodiments of the present application can be provided as methods, systems or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0138] The present application is described in reference to the flow diagrams and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the present application. It will be understood that each block of the flow diagrams and / or block diagrams, and combinations of blocks in the flow diagrams and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagram and / or block diagram in which the flow diagram and / or block diagram and its associated data Figure 1 The flow diagram and / or block diagram in which the flow diagram and / or block diagram and its associated data

[0139] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagram and / or block diagram in which the flow diagram and / or block diagram and its associated data Figure 1 The flow diagram and / or block diagram in which the flow diagram and / or block diagram and its associated data

[0140] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagram and / or block diagram in which the flow diagram and / or block diagram and its associated data Figure 1 The flow diagram and / or block diagram in which the flow diagram and / or block diagram and its associated data

[0141] It should be noted that any references made in the claims to an "apparatus" or "means" should not be construed to cover the corresponding structures only. Rather, such phrases are intended to more broadly encompass structures that are devoted to performing claimed functions and structures that can not be specifically made for such purpose. It is further noted that the claims can be drafted to exclude any optional element. As such, no optional element, optional process, or optional method steps are implied in the claims unless the specification indicates that such an element, process or step is essential.

[0142] While the preferred embodiments of the application have been described, additional variations and modifications can be made to the embodiments by those of skill in the art once given the benefit of the present disclosure. Therefore, the appended claims should not be construed to limit the scope of the application to the precise construction described. The various aspects of the application are intended to cover any and all modifications and changes within the scope of the present application.

[0143] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method for decoupling of coils based on current mode of butterfly coils, characterized in that, The method comprises: setting the first butterfly coil and the second butterfly coil to an initial overlapping state; controlling the first butterfly coil to be stationary and the second butterfly coil to rotate by a first angle about its own middle conductor axis; or controlling the second butterfly coil to be stationary and the first butterfly coil to rotate by the first angle about its own middle conductor axis; or controlling the first butterfly coil to rotate by a second angle about its own middle conductor axis and simultaneously controlling the second butterfly coil to rotate by a third angle about its own middle conductor axis; or controlling the first butterfly coil and the second butterfly coil to produce relative translation in a direction parallel to the coil plane; at each adjusted pose, establishing an equivalent circuit model of electromagnetic coupling between the middle conductors of the first butterfly coil and the second butterfly coil; extracting mutual inductance parameters between the two middle conductors from the equivalent circuit model; based on the mutual inductance parameters, calculating the resonant frequencies under common-mode excitation and differential-mode excitation respectively as common-mode resonant frequency and differential-mode resonant frequency; when the difference between the common-mode resonant frequency and the differential-mode resonant frequency in the resonant frequencies satisfies a preset condition, stopping adjustment and determining the relative spatial pose of the first butterfly coil and the second butterfly coil at this time as a target decoupling pose; wherein, at the time of stopping adjustment, there is a relative rotation angle or a relative translation amount between the two butterfly coils; and in a plane perpendicular to the middle conductors of the two butterfly coils, there is a projection offset amount between the projections of the middle conductors of the two butterfly coils; the geometric state defined by at least one of the relative rotation angle, the relative translation amount and the projection offset amount constitutes a decoupling configuration.

2. The method of claim 1, wherein, The step of controlling the first butterfly coil and the second butterfly coil to produce relative translation in a direction parallel to the coil plane comprises: controlling the first butterfly coil to be stationary and the second butterfly coil to translate by a first distance in a direction parallel to the middle conductor; or controlling the second butterfly coil to be stationary and the first butterfly coil to translate by the first distance in a direction parallel to the middle conductor; or controlling the first butterfly coil and the second butterfly coil to translate towards or away from each other in a direction parallel to the middle conductor of each coil respectively.

3. The method of claim 1, wherein, Before the step of calculating the resonant frequencies under common-mode excitation and differential-mode excitation, it comprises: applying excitation signals with the same phase to the first butterfly coil and the second butterfly coil to simulate the common-mode excitation condition; applying excitation signals with opposite phases to the first butterfly coil and the second butterfly coil to simulate the differential-mode excitation condition.

4. The method of claim 1, wherein, The step of determining the relative spatial pose of the first butterfly coil and the second butterfly coil at this time as a target decoupling pose when the difference between the common-mode resonant frequency and the differential-mode resonant frequency in the resonant frequencies satisfies a preset condition comprises: during the adjustment process, calculating the current actual difference between the common-mode resonant frequency and the differential-mode resonant frequency; when the actual difference is less than or equal to a preset maximum difference, it is determined that the preset condition is satisfied, and the current relative spatial pose is determined as the target decoupling pose.

5. The method of claim 1, wherein, The step of setting the first butterfly coil and the second butterfly coil in an initial overlapping state comprises: aligning the middle conductor of the first butterfly coil and the middle conductor of the second butterfly coil in parallel; moving the first butterfly coil or the second butterfly coil along the length direction of the middle conductor until the two middle conductors form an overlapping section in the length direction; wherein the length of the overlapping section is greater than zero and less than the full length of any middle conductor.

6. An empirical model construction method for butterfly coil decoupling design, characterized in that, The method of claim 1, comprising the following steps: obtaining a plurality of sets of sample data by performing the method of claim 1; wherein each set of sample data comprises at least: a size parameter of a butterfly coil, a decoupling configuration parameter in a target decoupling pose, and a resonant frequency parameter corresponding to the decoupling configuration parameter; constructing a structured data set based on the plurality of sets of sample data, the data set establishing a mapping relationship between the size parameter, the decoupling configuration parameter, and the resonant frequency parameter; training a preset model with the size parameter of the butterfly coil as an input feature and a relative spatial pose parameter as a prediction target, to generate an empirical model for predicting the decoupling configuration parameter of a butterfly coil of different sizes.

7. The method of claim 6, wherein, The decoupling configuration parameter predicted by the empirical model is at least one of the following parameters of the decoupling configuration: a relative rotation angle, a relative translation amount, or a projection offset amount.

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