Wireless charging receiving device, wireless charging transmitting device and electronic equipment

Abstract

The invention relates to the technical field of wireless charging, in particular to a wireless charging receiving device, a wireless charging transmitting device and electronic equipment, and the wireless charging receiving device is of a laminated structure and sequentially comprises a coil layer, a soft magnetic dielectric layer, a metal foil layer and an insulating bearing layer. The wireless charging transmitting device comprises a transmitting layer and a soft magnetic medium layer. The electronic equipment comprises the wireless charging receiving device and / or the wireless charging transmitting device. The wireless charging system effectively solves the problems that a traditional wireless charging system is high in circuit complexity, large in size and poor in anti-offset performance.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging, and in particular to an implantable wireless charging receiving device, a transmitting device and an electronic device with high stability. Background Art

[0002] Human implantable devices work by being implanted in the human body for a long time to achieve effective monitoring, auxiliary intervention or treatment of dysfunctional organs. They have shown a wide range of application trends and significant technological progress in various fields such as disease diagnosis, drug delivery, and perception, rehabilitation and health status detection. Wireless charging technology, as a non-contact power transfer technology, abandons the traditional wire connection method and can directly transmit power wirelessly from the power source to the load terminal. Therefore, through wireless charging, medical devices implanted in the body can be replenished without battery replacement through surgery, thereby eliminating the risk of complications (such as wound infection, etc.) and additional psychological burdens caused by repeated surgeries.

[0003] Faced with the complex internal environment of the human body and the differentiated requirements for implantation of various implants, in order to minimize the negative impact of implantation surgery on the patient's body and take into account the requirements of different implantation depths, the design of traditional wireless charging systems for human implantable devices usually faces many challenges such as insufficient battery life, limited anti-drift level, and excessive miniaturization difficulty. Therefore, the design of a miniature human implantable wireless charging magnetic coupling device with the advantages of stable energy supply and high reliability is imperative. Summary of the invention

[0004] The embodiments of the present invention provide a wireless charging receiving device, a transmitting device and an electronic device, which are used to at least solve the problems of high circuit complexity, large size and poor anti-drift performance of traditional wireless charging systems.

[0005] On the one hand, the present invention provides a wireless charging receiving device, which is a stacked structure, which includes a coil layer, a soft magnetic medium layer, a metal foil layer and an insulating bearing layer in sequence; the coil layer is provided with a first load output terminal and a second load output terminal for connecting a load; the first load output terminal is connected to the metal foil layer, and the second load output terminal, which serves as a dividing point between a series resonant cavity and a parallel resonant cavity, divides the coil layer into two areas, and the two areas respectively constitute the series resonant cavity and the parallel resonant cavity with the soft magnetic medium layer, the metal foil layer and the insulating bearing layer.

[0006] Optionally, the coil layer is composed of one or more layers, each layer is composed of a planar spiral coil; the parallel resonant cavity is composed of a first self-inductance and a first parasitic capacitance in parallel; the first self-inductance is the self-inductance of the planar spiral coil between the first load output terminal and the second load output terminal; the first parasitic capacitance includes the inter-turn capacitance corresponding to the planar spiral coil between the first load output terminal and the second load output terminal and the inter-plate capacitance between the planar spiral coil and the metal foil layer;

[0007] The series resonant cavity is connected in series with a second self-inductance and a second parasitic capacitance; the second self-inductance is the self-inductance of the planar spiral coil between the second load output end and the free end; the second parasitic capacitance includes the inter-turn capacitance corresponding to the planar spiral coil between the second load output end and the free end and the inter-plate capacitance between the planar spiral coil and the metal foil layer; the outer end of the planar spiral coil of the coil layer is suspended to form the free end.

[0008] Optionally, the position of the second load output terminal at each layer of the spiral coil satisfies the capacitance and inductance balance relationship between the series resonant cavity and the parallel resonant cavity:

[0009]

[0010] Wherein, L1 represents the first self-inductance, C1 represents the first parasitic capacitance, L2 represents the second self-inductance, and C2 represents the second parasitic capacitance.

[0011] Optionally, the position of the second load output terminal in each layer of the planar spiral coil is determined based on minimization of the resonant frequency error and constraints; the constraints include planar spiral coil engraving process restrictions, a capacitance-inductance balance relationship between the series resonant cavity and the parallel resonant cavity, and an outer diameter of the planar spiral coil.

[0012] Optionally, the following objective function is used to determine the minimization of the resonant frequency error ε:

[0013] |SRF-f0|<ε

[0014] Wherein, SRF represents the self-resonant frequency of the wireless charging receiving device, and f0 represents the preset operating frequency;

[0015] The capacitance and inductance balance relationship between the series resonant cavity and the parallel resonant cavity is:

[0016]

[0017] Wherein, L1 represents the first self-inductance, C1 represents the first parasitic capacitance, L2 represents the second self-inductance, and C2 represents the second parasitic capacitance.

[0018] Optionally, the self-inductance L of the planar spiral coil affected by the soft magnetic dielectric layer self_fe for:

[0019]

[0020] Where, L self_fe L1 or L2; L s ' elf Represents the self-inductance of the overall planar spiral coil; M fe (r i ,r j ) represents the mutual inductance between the i-th and j-th turns of the coil; n represents the number of turns of the coil;

[0021] The capacitance C between the coil layer and the metal foil layer in the first parasitic capacitor C1 and the second parasitic capacitor C2 pl The capacitance C between the coil layer and the soft magnetic medium layer pl (h coil ), capacitance C between soft magnetic dielectric layers pl (h fe ) and the capacitance C between the soft magnetic dielectric layer and the metal foil layer pl (h pl ) in series, which satisfies:

[0022]

[0023] The equivalent inter-turn capacitance C in the first parasitic capacitance C1 and the second parasitic capacitance C2 T As follows:

[0024]

[0025] In the formula, I s Represents the current in the coil; V s Indicates the terminal voltage of the coil.

[0026] Optionally, each layer is composed of a flexible insulating FPC material as the base and a copper engraved planar spiral coil; the soft magnetic medium layer is composed of a flexible ferrite sheet, and the flexible ferrite sheet is composed of a high-frequency and high magnetic permeability material, and its thickness does not exceed 0.1mm; the insulating bearing layer is a flexible insulating substrate with a thickness range of 0.04mm-0.06mm; the metal foil layer has a thickness range of 0.5oz-3oz.

[0027] On the other hand, the present invention also provides a wireless charging transmitter, which includes a transmitter layer and a soft magnetic medium layer; the transmitter layer is mainly composed of coils engraved on two sides of a substrate, wherein the coils on the first side are four coplanar square coils, and the four coplanar square coils are diagonally arranged and divided into two groups, and the winding directions of the two pairs of coils in each group are mirror-opposite; the coils on the second side are diamond coils, and the coils on the second side are located between the substrate and the soft magnetic medium layer.

[0028] Optionally, the two groups of coplanar square coils are independently excited, so that the excitation currents in the two groups of coplanar square coils remain consistent in amplitude and differ in phase by exactly 90 degrees; the diamond coils are independently excited.

[0029] On the other hand, an embodiment of the present invention provides an electronic device, which includes any one of the wireless charging receiving devices described above and / or any one of the wireless charging transmitting devices described above.

[0030] The wireless charging receiving device in the present invention is simple, has low circuit complexity, and has high parameter stability. In addition, the selection of physical capacitors is abandoned during the design process, making the overall structure safer and more reliable. The overall structure of the receiving device is compact and small in size, which can minimize the impact of human implants on the internal environment of the human body.

[0031] The wireless charging transmitter has strong anti-drift performance. Based on the principle of dynamic rotating magnetic field, it adopts a unique coil layout (including four square coils wound diagonally in opposite directions and a diamond coil arranged in the center) and a phase control strategy to successfully achieve wide-range, low-fluctuation and omnidirectional anti-drift magnetic field transmission.

[0032] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0034] Figure 1 An overall view of a wireless charging receiving device provided by an embodiment of the present invention;

[0035] Figure 2 An exploded diagram of a wireless charging receiving device provided in an embodiment of the present invention;

[0036] Figure 3 A schematic diagram of the distribution of the resonant cavity inductance and parasitic capacitance of the wireless charging receiving device provided in an embodiment of the present invention;

[0037] Figure 4 An equivalent circuit diagram of a wireless charging receiving device provided by an embodiment of the present invention;

[0038] Figure 5A parameter optimization flow chart of a wireless charging receiving device provided by an embodiment of the present invention;

[0039] Figure 6 A modeling calculation flow chart provided for an embodiment of the present invention;

[0040] Figure 7 A schematic diagram of equivalent conversion of a planar spiral coil provided by an embodiment of the present invention;

[0041] Figure 8 A schematic diagram of some parameters of a wireless charging receiving device provided by an embodiment of the present invention;

[0042] Fig. 9 An equivalent schematic diagram of an inter-turn capacitance port provided by an embodiment of the present invention;

[0043] Fig.10 An overall view of the wireless charging transmitter provided by an embodiment of the present invention;

[0044] Fig.11 An exploded view of a wireless charging transmitter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0046] In the subsequent description, the suffixes such as "module", "component" or "unit" used to represent elements are used only to facilitate the description of the present invention and have no specific meanings. Therefore, "module", "component" or "unit" can be used in a mixed manner. Expressions such as "first" and "second" are only used to distinguish technical terms.

[0047] Embodiment 1

[0048] An embodiment of the present invention provides a wireless charging receiving device, such as Figure 1 , 2As shown in Figure 3, the wireless charging receiving device is a stacked structure, which includes a coil layer (which may be composed of a planar spiral coil), a soft magnetic medium layer (which may be composed of a flexible ferrite sheet), a metal foil layer (which may be composed of a metal foil sheet) and an insulating bearing layer (which may be composed of a substrate); the coil layer is provided with a first load output terminal (referred to as output terminal B) and a second load output terminal (referred to as output terminal A) for connecting a load; the first load output terminal is connected to the metal foil layer, and the second load output terminal, which serves as a dividing point between a series resonant cavity and a parallel resonant cavity, divides the coil layer into two areas, and the two areas respectively constitute the series resonant cavity and the parallel resonant cavity with the soft magnetic medium layer, the metal foil layer and the insulating bearing layer.

[0049] In order to maximize the efficiency of power transmission while avoiding the increase in the human body's absorption of electromagnetic field energy due to excessively high operating frequency and the resulting biosafety risks and thermal effects, the system's resonant operating frequency should be in the high-frequency band of the MHz level.

[0050] The anti-deviation wireless charging system for implantable medical devices provided by the present invention can be used to charge any implantable medical device such as spinal cord stimulators, cardiac pacemakers, brain pacemakers, retinal prostheses, capsule endoscopes, cochlear implants, etc. In view of the problems of high circuit complexity, bulky volume and poor anti-deviation performance of traditional wireless charging systems, the wireless charging receiving device proposed in the embodiment of the present invention, as an anti-dislocation wireless charging transmitting device for implantable medical devices, belongs to a wireless charging magnetic coupling device. The receiving device is based on the principle of magnetic field coupling to form a self-resonant micro receiving device, which aims to abandon the physical compensation capacitor to simplify the circuit, reduce the size of the receiving end and improve the parameter stability performance. The receiving device effectively reduces the circuit complexity and has high parameter stability, and at the same time abandons the selection of physical capacitors to make the overall structure safer and more reliable. The overall structure of the receiving device is compact and small in size, which can minimize the impact of human implants on the internal environment of the human body, and can achieve self-resonance in the high-frequency band (3-30MHz). The wireless charging receiving device of the embodiment of the present invention can also be called a self-resonant receiving device, a self-resonant receiving device wireless charging self-resonant receiving device, etc.

[0051] In some embodiments, the parallel resonant cavity is connected in parallel by a first self-inductance L1 and a first parasitic capacitor C1; the first self-inductance L1 is the self-inductance of the planar spiral coil between the first load output terminal and the second load output terminal; the first parasitic capacitor C1 includes the inter-turn capacitance corresponding to the planar spiral coil between the first load output terminal and the second load output terminal and the inter-plate capacitance between the planar spiral coil and the metal foil;

[0052] The series resonant cavity is composed of a second self-inductance L2 and a second parasitic capacitor C2 in series; the second self-inductance L2 is the self-inductance of the planar spiral coil between the second load output terminal and the free end; the second parasitic capacitor C2 includes the inter-turn capacitance corresponding to the planar spiral coil between the second load output terminal and the free end and the inter-plate capacitance between the planar spiral coil and the metal foil; the outer end of the planar spiral coil of the coil layer is suspended to form the free end.

[0053] In some embodiments, the coil layer is composed of one or more layers, each layer is composed of a flexible insulating FPC material as a base to support a copper-engraved planar spiral coil (referred to as coil); the outer end of the planar spiral coil is a free end; the soft magnetic medium layer is composed of a flexible ferrite sheet, and the flexible ferrite sheet is composed of a high-frequency and high magnetic permeability material, and its thickness does not exceed 0.1mm; the insulating bearing layer is a flexible insulating substrate with a thickness range of 0.04mm-0.06mm; the metal foil layer has a thickness range of 0.5oz-3oz.

[0054] The receiver uses the dielectric properties of the flexible ferrite sheet and the inductance properties of the planar spiral coil to achieve self-resonance at high frequencies. The coil is divided into two parts, each of which consists of the coil's self-inductance and parasitic capacitance, and is connected in parallel at two points at the output end. The addition of the flexible ferrite sheet as a medium not only increases the coil's self-inductance, but also increases the capacitance between the coil and the metal foil, which is the key to achieving MHz-level self-resonance.

[0055] In some embodiments, Figure 1 , 2 As shown, the self-resonant receiving device is usually composed of four parts, namely, a coil layer composed of a planar spiral coil, a thin sheet made of a flexible high magnetic permeability material (such as a flexible nickel-zinc ferrite sheet, and the following description will be made of a flexible ferrite sheet unless otherwise specified), a metal foil layer made of a metal foil with high conductivity (such as copper, tin, silver, etc.), and a bearing layer under the metal foil (made of a flexible insulating FPC material).

[0056] The coil layer is made of a copper-engraved planar spiral coil with a flexible insulating FPC material as the base. The whole is inverted and stacked with a flexible ferrite sheet, and the two output terminals on it are placed on the back of the coil layer as output terminals in the form of pads through vias, which are marked as A and B respectively. The planar spiral coil contains three key nodes: output terminal A, output terminal B and the outer terminal, of which the outer terminal is suspended to form a free end. The output terminal B and the center position of the back copper foil layer are physically connected and fixed across the flexible ferrite sheet and the midpoint of the metal foil on the bottom substrate by means of a central perforation or external connection, using a filament made of a high conductivity material to cross the layer.

[0057] like Figure 3As shown, the output terminal A is used as a dividing point to divide the entire receiving device into two parts: a series resonant cavity and a parallel resonant cavity. The parallel resonant cavity is formed by the coil self-inductance L1 between the two points of the output terminals AB and the parasitic capacitance C1 such as the inter-turn capacitance corresponding to the section of the planar spiral coil and the inter-plate capacitance between the section and the metal foil in parallel, while the series resonant cavity is formed by the coil self-inductance L2 of the remaining part of the coil and the parasitic capacitance C2 such as the inter-turn capacitance corresponding to the section and the inter-plate capacitance between the section and the metal foil in series.

[0058] The equivalent circuit diagram is as follows Figure 4 As shown, the last two parts are connected in parallel via the output terminal AB and receive the electric energy from two points to output to the load. The output terminal A is used as the separation point between the series resonant cavity and the parallel resonant cavity, and the overall self-inductance of the coil layer is divided into two parts: the self-inductance of the series resonant cavity and the self-inductance of the parallel resonant cavity. Its position is one of the key factors in determining the self-resonant frequency of the overall receiving device. The calculation model can be constructed by combining the Newman formula and the parallel plate capacitor formula considering the edge effect and the partial element equivalent circuit method, and the self-inductance and parasitic capacitance in the resonant cavity are calculated and the self-resonance point is solved according to the equivalent circuit.

[0059] In order to reduce the negative impact of mechanical stress on human implants caused by the internal environment of the human body, the ferrite sheet and the metal foil are usually circular in shape, and their periphery needs to contain the largest spiral coil. All appropriate changes to the shape of the overall receiving device based on actual conditions fall within the scope of the present invention.

[0060] The flexible nickel-zinc ferrite sheet between the coil layer and the metal foil layer not only increases the self-inductance of the planar spiral coil, but also increases the inter-plate capacitance between the planar spiral coil and the metal foil as a metal conductor. It is a key element that enables the receiving device to achieve a self-resonant state at a MHz level operating frequency. When the entire receiving device operates in a self-resonant state, the dielectric loading of the flexible ferrite sheet and the inductive loading of the planar spiral coil make it have the properties of a short-circuit transmission line, achieving a self-resonant point at the MHz level.

[0061] In order to achieve the miniaturization design of the overall device and improve the space utilization of the device, such as Figure 1 The planar spiral coil shown is usually a planar circular spiral coil. According to the actual requirements of different medical implants, the circular spiral coil can also be a spiral coil of other shapes such as a square spiral coil, or a multi-layer planar coil, such as a multi-layer planar circular coil, a multi-layer planar square coil, etc. When the coil layer is a multi-layer planar coil, the AB point is also presented on the back of the coil layer in the form of a pad through a via. In order to ensure that the transmission efficiency of the magnetic coupling device is in a high state, the number of turns in the coil layer needs to be large (about dozens of turns) to increase the coil self-inductance and parasitic capacitance.

[0062] Considering the overall manufacturing process of the receiving coil, the ferrite sheet usually uses a flexible nickel-zinc ferrite magnetic isolation sheet, which is the same size as the outer diameter of the spiral coil. It is composed of high-frequency (applications above 5MHz) high magnetic permeability (magnetic permeability range of 120-180) materials (such as nickel-zinc ferrite, etc.), which can greatly reduce the magnetic loss of the coupling process. The thickness of the flexible nickel-zinc ferrite magnetic isolation sheet is usually set to no more than 0.1mm due to the manufacturing process and the application scenario of the implantable medical device. The use of too thick flexible nickel-zinc ferrite magnetic isolation sheets (exceeding 0.1mm) will not only affect the overall flexibility, but also further increase the distance between the coil layer and the copper foil layer, resulting in a reduction in parasitic capacitance, so that the self-resonant frequency cannot be adjusted to the predetermined resonance point. Overall, it meets the trend that the smaller the size of the receiving device, the thinner the thickness of the flexible ferrite sheet. The characteristics of small thickness and good flexibility of the ferrite sheet also provide convenience for the processing and manufacturing of the overall self-resonant receiving device.

[0063] The metal foil layer and the flexible insulating substrate carrier layer under the metal foil layer that plays a bearing role are usually integrated. The carrier layer is usually made of flexible insulating materials, such as polyimide materials. In order to maintain the overall flexibility and the stability of the process, the thickness of the carrier layer ranges from 0.04mm to 0.06mm, and the thickness is usually 0.05mm. The metal foil layer is laid on one side of the carrier layer and bonded to the flexible nickel-zinc ferrite sheet. The other side can be used to place electronic components related to medical implants as the load side to receive wirelessly transmitted power to complete medical effects such as electrical stimulation, etc., and can also be bonded to implantable medical devices with metal shells such as pacemakers and connect the output terminal AB to its battery through flying wires to form a loop for wireless charging. The overall thickness of the metal foil layer can be adjusted according to the external dimensions of different types of implants, with a thickness range of 0.5oz-3oz, usually thinner at 1oz. The overall size of the metal foil layer and the carrier layer remains the same as the outer diameter of the flexible ferrite sheet.

[0064] Parameters such as the thickness of the flexible ferrite sheet, the spacing between the top planar spiral coil and the bottom copper foil are usually pre-set in the standardized mass production process of the flexible ferrite sheet and are difficult to change. Therefore, the coil design needs to reasonably adjust the number of turns, wire diameter, wire gap and inner diameter to achieve the optimal solution for the performance of the overall energy transmission link within the human safety standard, such as Figure 5 As shown in the figure, the specific optimization process is as follows:

[0065] 1. Preset the operating frequency f0 and the outer diameter of the coil. Including:

[0066] Determine the preset operating frequency. Usually the operating frequency f0 is limited by human safety standards and related radio band protocols. Therefore, the appropriate self-resonant frequency (SRF) must be selected within the specified frequency range.

[0067] Determine the outer diameter of the coil. In practical application scenarios of different implantable medical devices, there are specific restrictions on the size of the self-resonant receiving device.

[0068] 2. Select the basic physical parameters of the coil and the position of output point A according to the constraints.

[0069] Design the basic physical parameters and local changes of the coil. Under the constraints of multiple restrictions such as PCB coil engraving process restrictions and the outer diameter requirements corresponding to different implantable medical devices, the self-resonant frequency of the planar spiral coil is determined by the physical parameters of the coil, such as the number of turns, wire diameter, wire gap, etc. By adjusting the value of the physical parameters and the position of the output terminal A and making local changes to the parameters, the self-resonant frequency is close to the preset operating frequency f0.

[0070] 3. Modeling and calculation.

[0071] 4. |SRF-f0|<ε

[0072] Calculate the error ε between the coil self-resonant frequency SRF and the preset operating frequency f0. Through calculation and multiple parameter adjustments and iterations, the self-resonant frequency is matched with the preset operating frequency f0, and the frequency error is reduced to meet the requirements. Usually, there are multiple sets of basic physical parameter combinations of the coil that meet the self-resonant frequency error conditions.

[0073] Parameter Process Design In the subsequent design stage, the above process can be used to accurately calculate and optimize the key parameters of the coil such as the wire diameter and wire gap, which can ensure that the receiving device as a whole reaches a resonant state and meets specific design standards and performance requirements. This parameter optimization strategy helps to improve energy transmission efficiency and ensure that the system operates at the predetermined operating frequency.

[0074] Detailed, such as Figure 6 As shown, the basic parameters of the receiving device refer to basic physical parameters such as the basic wire diameter and wire gap of the spiral coil, thickness of different dielectric layers and their gaps. The selection of the physical position of point A mainly determines the planar spiral coil and parasitic capacitance in the series resonant cavity and the parallel resonant cavity through the change. The above decision variables are used to achieve the optimization goal of minimizing the resonant frequency error between the resonant frequency of the overall device and the preset frequency. That is, the position of the second load output terminal on each layer of the planar spiral coil is determined based on the minimization of the resonant frequency error and constraints; the constraints include the planar spiral coil engraving process constraints, the capacitance and inductance balance relationship between the series resonant cavity and the parallel resonant cavity, and the outer diameter of the planar spiral coil.

[0075] The main constraints are:

[0076] 1. Restrictions on coil engraving process. Since the engraving process of printed planar spiral coils and circuit boards has manufacturing accuracy limitations, the minimum wire diameter and wire gap of coil engraving need to be considered in the optimization of the physical position of point A.

[0077] 2. The capacitance and inductance balance relationship between the series resonant cavity and the parallel resonant cavity. Figure 4 As shown in FIG. 1 , the self-resonant receiving device mainly relies on the self-inductance of the planar spiral coil and the parasitic capacitance in the coil to form an equivalent series resonance to achieve a self-resonant state at the resonant frequency, wherein the parasitic capacitances C2 and C1 are both composed of the inter-board capacitance C between the planar spiral coil corresponding to each part of the top layer and the copper foil of the bottom layer. pl The inter-turn capacitance C of the planar spiral coil T The circuit consists of two parts. The inter-plate capacitor is connected in series with the coil, while the inter-turn capacitor is connected in parallel with the coil.

[0078] The difference in the position of point A leads to the difference in parasitic capacitance and inductance of the spiral coil in the series resonant cavity and the parallel resonant cavity. When the whole device works at the series resonant point, the whole device should satisfy the following equation according to point A to ensure the overall resonance, that is, the position of the second load output terminal at each layer of the spiral coil satisfies the capacitance and inductance balance relationship of the series resonant cavity and the parallel resonant cavity:

[0079]

[0080] According to the above formula, the series self-resonant frequency can be obtained as:

[0081]

[0082] The relationship between parasitic capacitance, inter-board capacitance and inter-turn capacitance is (taking C1 as an example):

[0083] C1=C pl_1 +C T_1 (3)

[0084] 3. Coil outer diameter requirements for different implantable medical devices. In the actual application scenarios of different implantable medical devices, there are specific restrictions on the size of the overall device. The selection of the physical location of point A should not exceed the limit range of the overall outer diameter of the coil.

[0085] 4. Parameter groups that meet the requirements.

[0086] 5. Perform trend analysis on the parameter groups that meet the requirements and select the optimal parameters.

[0087] By plotting graphs of multiple sets of coil physical parameters and comparing and analyzing their comprehensive trends under quality factor, coupling coefficient, VSWR and SRF constraints, the optimal coil parameter configuration can be screened out, thereby ensuring that the selected parameters can achieve efficient and safe energy transmission in practical applications.

[0088] The modeling calculation mainly includes the self-inductance modeling of the planar spiral coil, the inter-plate capacitance modeling, and the coil inter-turn capacitance modeling.

[0089] 1. Planar spiral coil self-inductance modeling

[0090] Each coil has its own inductance and mutual inductance with other coils. Since the inductance is proportional to the magnetic flux and the magnetic flux changes linearly, the mutual inductance between the two windings is not affected by the current of other windings. Set the radius of any two concentric rings, i and j, to r. i With r j ,ds i With ds j Represent any length of infinitesimal element in two concentric rings. According to Newman's formula, the mutual inductance M between any two turns of coils (the i-th concentric ring and the j-th concentric ring) can be obtained. ij :

[0091]

[0092] Where the radius difference between the i-th turn and the j-th turn in the coil is r ij , using elliptic integrals to simplify the above formula, we can get the mutual inductance M(r i ,r j ):

[0093]

[0094] Where K and E represent the first and second kind of elliptic integrals respectively, μ represents the magnetic permeability, and k0 represents the relative position relationship between the two rings, which is expressed as:

[0095]

[0096] Due to the high operating frequency, the internal self-inductance of the magnetic ring can be ignored. Therefore, the external self-inductance can be calculated by the magnetic flux passing through the inner contour of the ring caused by the current in the center of the wire. The self-inductance of each turn of the coil is equivalent to the mutual inductance between two circular rings with these radii, so the circular ring r i The self-sensitivity L(r i ) is expressed as follows:

[0097]

[0098] When the number of turns in the planar spiral coil is large and the wire diameter and wire gap are small, the size change of each turn and adjacent coils is small and the whole is similar to a ring. Figure 7 As shown, in order to simplify the characteristic structure of the coil, the planar spiral coil is abstracted into multiple concentric circular coils.

[0099] Considering the influence of the same-name terminals when the coils are connected, for any two turns of the coils:

[0100] L(r i ,r i+1 )=L(ri )+L(r i+1 )+2M(r i ,r i+1 ) (8)

[0101] By summing the multiple turns of coil n, the self-inductance L of the overall planar spiral coil is s ' elf It can be expressed as:

[0102]

[0103] Among them, the flexible ferrite sheet under the planar spiral coil in the self-resonant receiving device plays a role in enhancing the self-inductance of the coil. When the thickness of the flexible ferrite sheet is limited, the self-inductance of the coil containing ferrite can be solved by mirroring. The mirror method converts the self-inductance of the coil due to the ferrite into the mutual inductance between the original coil and the mirror coil with the ferrite as the symmetry axis for equivalent calculation. In practical applications, since the relative magnetic permeability of ferrite is usually very high, the effect of its thickness on the inductance and mutual inductance of the coil can be ignored. Therefore, when solving the self-inductance and mutual inductance caused by the same ferrite core, only one mirror calculation is required to obtain a more accurate result. Among them, the current I in the mirror coil r satisfy:

[0104]

[0105] Where μ r is the relative magnetic permeability of the flexible ferrite sheet, I s represents the current in the coil. In some embodiments, the flexible ferrite sheet used is a nickel-zinc ferrite sheet, and its relative magnetic permeability is usually 120 to 180. It can be obtained that the image current is basically the same as the current inside the coil. According to the above formula, it can be obtained:

[0106]

[0107] Where I r Represents the secondary current, I s represents the mirror coil current, M'(r i ,r j ) is the mutual inductance between the original coil and the mirror image coil. Since the symmetry is based on the flexible ferrite sheet, there is a vertical gap between the original coil and the mirror image coil. The difference between the two is k0. Since the vertical misalignment between the coil and the mirror image coil is increased during the mirroring process, k'0 representing the relative position relationship is corrected by k0. K'0 is used to replace k0 in equation (5) to determine M'(r i ,r j ). k'0 is as follows:

[0108]

[0109] In summary, the self-inductance L of the planar spiral coil affected by the soft magnetic medium layer (considering the flexible ferrite sheet) in the self-resonant coil self_fe Can be integrated into:

[0110]

[0111] 2. Modeling of inter-board capacitance

[0112] In the self-resonant receiving device, the interval between the planar spiral coil and the copper foil can be divided into three parts by the flexible ferrite sheet, and the parameters between them are as follows Figure 8 shown.

[0113] Among them, the layer gap parameters satisfy:

[0114] h=h coil +h fe +h pl (14)

[0115] In the formula, h coil Indicates the vertical distance between the coil layer and the soft magnetic medium layer, h pl represents the vertical distance between the soft magnetic medium layer and the metal foil layer, that h fe Indicates the thickness of the soft magnetic dielectric layer.

[0116] Since both the planar spiral coil and the copper foil are regular conductors, the capacitance between the plates can be initially utilized as the capacitance C' of two parallel conductors. pl The formula is as shown below:

[0117]

[0118] where ε r ε0 represents the dielectric constant of two parallel conductors, S represents the area between the two parallel conductors, and h x represents the vertical distance between two parallel conductors, h x Can be h coil 、h fe h pl The coil layer and the soft magnetic medium layer are equivalent to two parallel conductors, as follows

[0119]

[0120] S, h coilRepresent the facing area and vertical distance between the coil layer and the metal foil layer respectively, and l represents the length of the coil. However, the self-resonant receiving device itself is small in size and the planar spiral coil is very close to the ferrite in the lower layer. In a specific geometric layout where the conductor spacing is close to the conductor size, the capacitance effect formed by the side wall and back of the conductor may have a significant impact on the overall capacitance characteristics, which is the edge effect. Since the wire diameter and the distance between the plates are small, the edge effect of the capacitor needs to be considered when calculating the capacitance between the plates. The following formula takes the distance from the coil layer to the soft magnetic medium layer as an example, and the capacitance considering the edge effect can be expressed as:

[0121]

[0122] Inter-board capacitance C pl (h fe ) and C pl (h pl ) Calculation method is the same as C pl (h coil ) is the same, and C in formula (17) pl (h coil ) is replaced by C pl (h fe ) and C pl (h pl ), C pl '(h coil ) is replaced by C pl (h fe )' and C pl '(h pl )

[0123] The capacitance C between the coil layer and the metal foil layer pl By C pl (h coil ), C pl (h fe ) and C pl (h pl ) in series, then it satisfies:

[0124]

[0125] The capacitance C between the coil layer and the metal foil layer in the first parasitic capacitor C1 and the second parasitic capacitor C2 pl The calculation is the same.

[0126] 3. Modeling of coil turn-to-turn capacitance

[0127] The inter-turn capacitance of the coil is affected by many factors, such as the area of ​​adjacent sides of the inter-turn coil, the mutual capacitance of non-adjacent coils, etc. Although the thickness of the coil in a planar spiral coil is usually 1Oz, the distance between the coil turns is extremely small (about 0.1mm), so the influence of the inter-turn capacitance in the process of building the overall self-resonance state cannot be ignored. And because the wire diameter and thickness of the coil are not too different and the number of turns is large, the inter-turn capacitance of the self-resonant coil cannot be directly solved using traditional methods.

[0128] In some embodiments, starting from the coil charge distribution, the inter-turn induced potential is analyzed to complete the equivalent calculation of the inter-turn capacitance. Each coil turn can be regarded as a charge ring with linear charge density, which satisfies λ i =Q i / 2πr i . Calculate its potential distribution based on the Cartesian coordinate system. From this, the potential between any two positions can be obtained and solved using Coulomb integral as follows:

[0129]

[0130] In the integral loop C, z represents the vertical distance between two points, represents the angle element, and ds represents the distance element. The above formula can be further simplified to obtain the induced potential between any two turns of the coil:

[0131]

[0132] Since the charge is evenly distributed on each turn of the coil, the inductive charge coefficient is defined as v ji ,satisfy:

[0133]

[0134] Assuming that the coil has n turns in total, the induced potential and corresponding charge between any two turns of the coil are integrated into a matrix form, which can satisfy the following relationship:

[0135]

[0136] From the above formula, we can see that the induced charge coefficient [v ji ] and the quasi-turn capacitance matrix are inverse matrices of each other and contain the charge relationship of each conductor relative to the potential. From this, the turn-to-turn capacitance matrix can be obtained as:

[0137]

[0138] in:

[0139]

[0140] Since the inter-turn capacitance matrix can only reflect the inter-turn capacitance between any two turns, it is necessary to perform equivalent integration on the matrix. The inter-turn capacitance distribution of the coil is based on Kirchhoff's law, and the inter-turn capacitance matrix satisfies the following relationship:

[0141]

[0142] Where V i Represents node r i and r n By solving the above equation, the equivalent turn-to-turn capacitance C can be calculated. T As follows:

[0143]

[0144] Where V s Indicates the terminal voltage of the coil.

[0145] The equivalent inter-turn capacitance C in the first parasitic capacitance C1 and the second parasitic capacitance C2 T The calculation is the same.

[0146] Embodiment 2

[0147] In order to improve the anti-drift performance of the overall wireless charging system, the embodiment of the present invention designs and implements a wireless charging transmitter based on the principle of a dynamic rotating magnetic field, such as Fig.10 , 11 As shown, the wireless charging transmitting device includes a transmitting layer and a soft magnetic medium layer (which can be composed of a flexible ferrite sheet); the transmitting layer is mainly composed of coils engraved on both sides of a substrate (which can be composed of a flexible insulating substrate), wherein the coils on the first side are four coplanar square coils, the four coplanar square coils are diagonally arranged and divided into 2 groups, and the winding directions of the two pairs of coils in each group are mirror-opposite; the coils on the second side are diamond-shaped coils, and the coils on the second side are located between the substrate and the soft magnetic medium layer.

[0148] The designed combined transmitting device achieves wide-range, low-fluctuation and omnidirectional anti-deviation magnetic field transmission efficiency through coil layout and phase control strategy.

[0149] The embodiment of the present invention realizes a transmitting device based on the dipole combination principle, which is composed of four coplanar square coils engraved on the front of a flexible insulating substrate and a diamond coil engraved on the back of the flexible insulating substrate, and cooperates with the packaging at the bottom of the coil and the flexible ferrite sheet to form a complete transmitting device. Among them, the square coils are planar spiral coils and are arranged in pairs in a diagonal group, and the winding direction of each pair of coils in a group is mirror-opposite. This design of reverse winding of diagonal coils is intended to enhance the coverage of the magnetic field, thereby laying the foundation for improving the anti-deviance performance of the system.

[0150] The transmitting device of the embodiment of the present invention adopts a coil configuration including diagonally reversed series-connected square coils and a central diamond coil to optimize the magnetic field distribution, and at the same time combines a phase control strategy to achieve a wide range, low fluctuation and omnidirectional magnetic field emission, thereby enhancing its adaptability and stability in different medical application scenarios.

[0151] In order to achieve stability and low volatility of magnetic field output, an excitation control strategy that matches the spatial layout of the coils must also be designed. To this end, two sets of square coils are independently excited so that the excitation currents in the two sets of coils remain consistent in amplitude and differ in phase by exactly 90 degrees, thereby generating a dynamic rotating magnetic field. The diagonal coils are connected in reverse series, so only two independent excitation sources are needed to effectively drive the four square coils to form four excitation sources with different phases. This control strategy can keep the excitation phase difference between any two adjacent square coils constant at 90 degrees, ensuring precise synchronization of magnetic field rotation. Under the dual effects of symmetrical structure and symmetrical excitation strategy, the synthesized flux vector exhibits regular clockwise or counterclockwise rotation characteristics.

[0152] Traditional dynamic rotating magnetic field transmitting mechanisms usually have an energy dead zone at the junction of adjacent coils. When the receiving coil is in a position that is almost parallel to the junction of the adjacent coil, only a small amount of net magnetic flux passes through the receiving coil, and the coupling effect with the transmitting side drops sharply. In order to solve this problem, the diamond coil at the center of the transmitting device is powered by an independent excitation source, which can stably generate unidirectional magnetic flux to compensate for the energy dead zone generated by the dynamic rotating magnetic field. Fig.11 The diamond coil shown is also a planar spiral coil, and both ends of the coil are independently connected to an excitation source.

[0153] In some embodiments, the holding component below the transmitting coil is the bottom shell of the transmitting device, which plays a role of packaging and protection and can be made of any insulating material. A ferrite sheet is placed under the transmitting coil to enhance the overall transmitting magnetic flux, and the ferrite material is the same as that used in the receiving device.

[0154] When the receiving coil is horizontally misaligned, it mainly picks up the vertical magnetic flux emitted by the square coil and the diamond coil; therefore, when the receiving coil is rotationally misaligned, it mainly picks up the rotating magnetic flux generated by the two sets of square coils. Regardless of the azimuth angle of the receiving coil, it can receive stable transmitted magnetic field energy. This greatly improves the system's anti-deviation capability in all directions and can effectively deal with the multi-angle misalignment of the receiving device caused by normal physiological movements of the human body.

[0155] Embodiment 3

[0156] The present invention provides an electronic device, which includes the wireless charging receiving device described in any one of the first embodiments and / or the wireless charging transmitting device described in any one of the second embodiments.

[0157] The electronic device may be a wireless charging system, which may be used for an anti-deviated wireless charging system for implantable medical devices, and may be used to charge any implantable medical device such as a spinal cord stimulator, a cardiac pacemaker, a brain pacemaker, a retinal prosthesis, a capsule endoscope, a cochlear implant, etc. It may also be the above-mentioned implantable medical device, in which the wireless charging receiving device in the first embodiment and / or the wireless charging transmitting device in the second embodiment are arranged.

[0158] The effects of the third embodiment can be referred to the first and second embodiments, which will not be described in detail here.

[0159] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0160] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0161] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A wireless charging receiving device, characterized in that: The wireless charging receiving device is a stacked structure, which includes a coil layer, a soft magnetic medium layer, a metal foil layer and an insulating bearing layer in sequence; the coil layer is provided with a first load output terminal and a second load output terminal for connecting a load; the first load output terminal is connected to the metal foil layer, and the second load output terminal, which serves as a dividing point between a series resonant cavity and a parallel resonant cavity, divides the coil layer into two areas, and the two areas respectively constitute the series resonant cavity and the parallel resonant cavity with the soft magnetic medium layer, the metal foil layer and the insulating bearing layer.

2. The wireless charging receiving device according to claim 1, characterized in that: The coil layer is composed of one or more layers, each layer is composed of a planar spiral coil; the parallel resonant cavity is connected in parallel by a first self-inductance and a first parasitic capacitance; the first self-inductance is the self-inductance of the planar spiral coil between the first load output terminal and the second load output terminal; the first parasitic capacitance includes the inter-turn capacitance corresponding to the planar spiral coil between the first load output terminal and the second load output terminal and the inter-plate capacitance between the planar spiral coil and the metal foil layer; The series resonant cavity is connected in series with a second self-inductance and a second parasitic capacitance; the second self-inductance is the self-inductance of the planar spiral coil between the second load output end and the free end; the second parasitic capacitance includes the inter-turn capacitance corresponding to the planar spiral coil between the second load output end and the free end and the inter-plate capacitance between the planar spiral coil and the metal foil layer; the outer end of the planar spiral coil of the coil layer is suspended to form the free end.

3. The wireless charging receiving device according to claim 2, characterized in that: The position of the second load output terminal at each layer of the spiral coil satisfies the capacitance and inductance balance relationship between the series resonant cavity and the parallel resonant cavity: Wherein, L1 represents the first self-inductance, C1 represents the first parasitic capacitance, L2 represents the second self-inductance, and C2 represents the second parasitic capacitance.

4. The wireless charging receiving device according to claim 2, characterized in that: The position of the second load output terminal on each layer of the planar spiral coil is determined based on minimizing the resonant frequency error and constraints; the constraints include the planar spiral coil engraving process restrictions, the capacitance and inductance balance relationship between the series resonant cavity and the parallel resonant cavity, and the outer diameter of the planar spiral coil.

5. The wireless charging receiving device according to claim 4, characterized in that: The following objective function is used to minimize the resonant frequency error ε: |SRF-f0|<ε Wherein, SRF represents the self-resonant frequency of the wireless charging receiving device, and f0 represents the preset operating frequency; The capacitance and inductance balance relationship between the series resonant cavity and the parallel resonant cavity is: Wherein, L1 represents the first self-inductance, C1 represents the first parasitic capacitance, L2 represents the second self-inductance, and C2 represents the second parasitic capacitance.

6. The wireless charging receiving device according to claim 5, characterized in that: Self-inductance L of planar spiral coil affected by soft magnetic dielectric layer self_fe for: Where, L self_fe L1 or L2; L s ' elf Represents the self-inductance of the overall planar spiral coil; M fe (r i ,r j ) represents the mutual inductance between the i-th and j-th turns of the coil; n represents the number of turns of the coil; The capacitance C between the coil layer and the metal foil layer in the first parasitic capacitor C1 and the second parasitic capacitor C2 pl The capacitance C between the coil layer and the soft magnetic medium layer pl (h coil ), capacitance C between soft magnetic dielectric layers pl (h fe ) and the capacitance C between the soft magnetic dielectric layer and the metal foil layer pl (h pl ) in series, which satisfies: The equivalent inter-turn capacitance C in the first parasitic capacitance C1 and the second parasitic capacitance C2 T As follows: In the formula, I s Represents the current in the coil; V s Indicates the terminal voltage of the coil.

7. The wireless charging receiving device according to any one of claims 1 to 6, characterized in that: Each layer is composed of a flexible insulating FPC material as the base and a copper-engraved planar spiral coil; the soft magnetic medium layer is composed of a flexible ferrite sheet, and the flexible ferrite sheet is composed of a high-frequency and high-magnetic permeability material, and its thickness does not exceed 0.1mm; the insulating bearing layer is a flexible insulating substrate with a thickness range of 0.04mm-0.06mm; the metal foil layer has a thickness range of 0.5oz-3oz.

8. A wireless charging transmitter, characterized in that: The wireless charging transmitting device includes a transmitting layer and a soft magnetic medium layer; the transmitting layer is mainly composed of coils engraved on two sides of a substrate, wherein the coils on the first side are four coplanar square coils, the four coplanar square coils are diagonally arranged and divided into two groups, and the winding directions of the two pairs of coils in each group are mirror-opposite; the coils on the second side are diamond-shaped coils, and the coils on the second side are located between the substrate and the soft magnetic medium layer.

9. The wireless charging transmitter according to claim 8, characterized in that: The two groups of coplanar square coils are excited independently, so that the excitation currents in the two groups of coplanar square coils remain consistent in amplitude and differ in phase by exactly 90 degrees; the diamond coils are excited independently.

10. An electronic device, characterized in that: The electronic device comprises a wireless charging receiving device as claimed in any one of claims 1 to 8 and / or a wireless charging transmitting device as claimed in any one of claims 8 to 9.

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