Adaptive tuning method for wireless charging system based on double-sided reuse of magnetic core

Abstract

This invention relates to the field of wireless charging technology and discloses an adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse. This method, used in wireless charging systems, includes the following steps: a receiver controller monitors the current energy transfer efficiency η_cur of the wireless charging system in real time through an efficiency monitoring module; the receiver controller performs a perturbation-observation closed-loop optimization on the piezoelectric ceramic variable capacitor C... tune A preset perturbation is applied to the driving voltage to adjust the equivalent capacitance value of the parallel resonant branch; S1 and S2 are repeated to enable the wireless charging system to dynamically track and maintain near the maximum efficiency point when the coupling coefficient changes due to changes in the receiver's pose. This invention employs a double-sided multiplexed magnetic circuit, deeply coordinating the magnetically shielded anti-interference magnetic integrated structure with the closed-loop tuning algorithm, effectively solving the coupling crosstalk problem caused by same-side integration.

Description

Technical Field

[0001] This invention relates to the field of wireless charging technology, and in particular to an adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse. Background Technology

[0002] Robots are increasingly used in home services, healthcare, and industrial collaboration. Wireless charging technology, with its advantages of contactless power supply, automated docking, and high protection levels, has become the preferred solution for autonomous power replenishment of robots. The bilateral LCC compensation topology is widely used in the wireless charging field due to its constant current output, flexible tuning, and strong robustness to parameter changes. A schematic diagram of this topology circuit is shown below. Figure 1 As shown, the receiver typically requires two inductors: the self-inductance of the receiving coil and a parallel resonant inductor. In a traditional receiver layout, the receiver comprises two parts: a receiving coil assembly and a receiving controller. The receiving coil assembly is usually composed of an integrated receiving coil and a magnetic core; while the parallel resonant inductor is housed as a separate wire-wound ferrite element within the receiving controller. To reduce the size of the receiving controller, existing technology attempts to make the parallel resonant inductor into a planar coil form and arrange this planar coil and the receiving coil on the same side surface of the same magnetic core within the receiving coil assembly (same-side integration).

[0003] However, this co-side arrangement introduces a serious spatial coupling interference problem: due to the close proximity and lack of shielding between the resonant coil and the transmitting coil, unexpected additional mutual inductance is generated between them. This additional mutual inductance causes the total mutual inductance parameter of the system to drift, resulting in a severe shift in the resonant operating point, causing impedance mismatch and a significant decrease in transmission efficiency. In other words, the co-side integration scheme sacrifices electromagnetic compatibility and transmission stability for increased integration density.

[0004] On the other hand, in practical use, it is difficult for robots to perfectly align with the charging transmitter every time they dock. Posture deviation will significantly change the coupling coefficient, leading to system detuning and a sharp drop in efficiency. Existing solutions mostly use frequency conversion control or impedance matching networks to address this, but frequency conversion may exceed the specified frequency band, and impedance matching networks increase circuit complexity and size.

[0005] Therefore, two interrelated technical problems need to be solved in this field: first, how to eliminate unintended coupling interference when integrating parallel resonant inductors; and second, how to achieve efficient and stable adaptive tuning under pose offset. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art. The present invention proposes an adaptive tuning method for a wireless charging system based on double-sided reuse of magnetic core, which solves the problems in the prior art where the receiving coil assembly is arranged on the same side when integrated with a parallel resonant inductor, which easily generates unexpected coupling interference, and the problem that the pose offset leads to low charging efficiency.

[0007] The technical solution of this invention is as follows: This invention discloses an adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse. This method is used in a wireless charging system, which includes a transmitter and a receiver coupled to the transmitter. The receiver includes a receiving coil assembly and a receiving controller. The receiving controller includes a control module, a dynamic tuning module, a rectification and filtering unit, and an efficiency monitoring module. The method includes the following steps: S1. The receiver controller monitors the current energy transmission efficiency η_cur of the wireless charging system in real time through the efficiency monitoring module; S2. The receiving controller performs a closed-loop optimization using the perturbation-observation method, applying a preset perturbation to the driving voltage of the piezoelectric ceramic variable capacitor Ctune to adjust the equivalent capacitance value of the parallel resonant branch. S3. Repeat S1 and S2 to enable the wireless charging system to dynamically track and maintain near the point of maximum efficiency when the coupling coefficient changes due to the change in the pose of the receiver.

[0008] In S2, S2 specifically includes the following steps: S2.1. Using the current driving voltage V_cur of the piezoelectric ceramic variable capacitor as a reference, and the current energy transfer efficiency η_cur, apply a positive voltage perturbation ΔV, and measure the energy transfer efficiency η_pos after the perturbation. S2.2 Determine whether η_pos is greater than η_cur + δ, where δ is greater than the preset efficiency threshold for measuring system noise; if so, accept a positive disturbance + ΔV, update V_cur and η_cur, keep ΔV unchanged, and return to S1; otherwise, apply a negative disturbance - ΔV and measure the efficiency η_neg after the disturbance. S2.3. Determine if η_neg is greater than η_cur + δ. If so, accept the negative perturbation, update V_cur and η_cur, keep ΔV unchanged, and return to S1. Otherwise, reduce the step size by half. ΔV1 = ΔV / 2; Where ΔV1 is the updated step size; S2.4 Determine whether ΔV1 is greater than the minimum step size ΔV_min. If so, return to S1 to continue iterating; otherwise, maintain the current driving voltage V_cur.

[0009] As can be seen from the above scheme, the structure and algorithm of this invention are deeply synergistic. The shielding structure ensures the purity of the feedback signal, enabling the perturbation-observation method to converge stably and avoiding misjudgments and oscillations. This invention obtains real-time transmission efficiency through an efficiency monitoring module and dynamically adjusts the piezoelectric ceramic variable capacitor connected in parallel across the receiving parallel compensation capacitor using the perturbation-observation method to adjust the equivalent capacitance of the parallel resonant branch. This invention deeply synergizes the magnetically shielded anti-interference magnetic integrated structure with the closed-loop tuning algorithm, effectively solving the coupling crosstalk problem caused by same-side integration, significantly improving the efficiency and robustness of the wireless charging system under pose shift, and is especially suitable for wireless charging scenarios for mobile robots.

[0010] It also includes anomaly handling steps. If the efficiency monitoring module detects that the energy transmission efficiency η_cur is lower than the preset safety threshold η0 and cannot be recovered after multiple optimization attempts, it is determined to be a system anomaly, and the transmission power is automatically reduced and an alarm signal is issued. If the anomaly continues for more than a set time t, charging is stopped.

[0011] The receiving coil assembly includes a resonant coil layer, a first magnetic core layer, a receiving coil layer, and an insulating protective layer arranged sequentially. The receiving coil layer and the resonant coil layer are respectively disposed on both sides of the first magnetic core layer. The resonant coil layer is disposed away from the transmitting end, and the receiving coil layer is disposed towards the transmitting end. The first magnetic core layer forms a magnetic shield for the resonant coil layer. The receiving controller is electrically connected to the resonant coil layer and the receiving coil layer respectively.

[0012] As can be seen from the above scheme, the transmitting end and the receiving end achieve wireless charging through coupling. The receiving coil assembly uses the resonant coil layer, which acts as a parallel resonant inductor, and the receiving coil layer, respectively, to be set on both sides of the first magnetic core layer, forming a double-sided multiplexed magnetic circuit. This invention utilizes the body of the first magnetic core layer as a low magnetic reluctance shielding layer to shield the resonant coil layer on the back of the magnetic core, reducing the unexpected coupling coefficient between the two, cutting off crosstalk from the physical structure, avoiding detuning, and cutting off the coupling interference of the resonant branch to the main power channel. This provides an electromagnetic environment that does not require compensation for mutual inductance changes for subsequent adaptive tuning. By providing the magnetic circuit for both the resonant coil layer and the receiving coil layer simultaneously through the first magnetic core layer, the amount of magnetic core used is significantly reduced.

[0013] The first magnetic core layer has at least one opening. Therefore, the opening is used to adjust the inductance of the resonant coil layer, thereby avoiding affecting the inductance of the receiving coil layer.

[0014] The width of the opening is 0.5mm to 2.0mm, and the depth of the opening is 20% to 50% of the thickness of the first magnetic core layer. Therefore, the opening allows the inductance to be continuously adjustable within a certain range, facilitating matching the resonant frequency requirements of the LCC topology.

[0015] Both the resonant coil layer and the receiving coil layer employ planar helical coils, with the coil winding directions of the resonant coil layer and the receiving coil layer being opposite. Therefore, the magnetic flux generated by the resonant coil layer and the receiving coil layer in the first magnetic core layer has the same direction, achieving magnetic flux superposition and enhancement.

[0016] The receiving coil assembly further includes a second magnetic core layer, and the resonant coil layer is disposed between the first magnetic core layer and the second magnetic core layer.

[0017] The transmitting end adopts an LCC compensation topology, and the receiving end adopts an LCC compensation topology. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the receiving coil assembly; Figure 2 This is a connection diagram of a wireless charging system; Figure 3 This is a connection diagram of the receiver in a wireless charging system; Figure 4 This is a schematic diagram of the structure of the first magnetic core layer; Figure 5 This is a schematic diagram of the circuit connection at the receiving end; Figure 6 This is a circuit connection diagram of a wireless charging system; Figure 7 This is a flowchart of the adaptive tuning method; Figure 8 This is a control diagram of the adaptive tuning method. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0020] like Figures 1 to 8As shown, this invention discloses a wireless charging system based on double-sided magnetic core reuse. The wireless charging system includes a transmitter and a receiver coupled to the transmitter. The receiver includes a receiving coil assembly and a receiving controller 600. The receiving coil assembly includes a resonant coil layer 200, a first magnetic core layer 300, a receiving coil layer 400, and an insulating protective layer 500 arranged sequentially. The receiving coil layer 400 and the resonant coil layer 200 are respectively disposed on opposite sides of the first magnetic core layer 300. The resonant coil layer 200 is positioned away from the transmitter, and the receiving coil layer 400 is positioned towards the transmitter. The first magnetic core layer 300 forms a magnetic shield for the resonant coil layer 200, such that within a preset operating offset range, the unintended coupling coefficient k between the resonant coil layer and the transmitting coil is ≤0.025. The receiving controller 600 is electrically connected to both the resonant coil layer 200 and the receiving coil layer 400.

[0021] The first magnetic core layer 300 is provided with at least one opening 310 for adjusting the inductance of the resonant coil layer 200. The width of the opening 310 is 0.5mm to 2.0mm, and the depth of the opening 310 is 20% to 50% of the thickness of the first magnetic core layer 300.

[0022] In this embodiment, both the resonant coil on the resonant coil layer 200 and the receiving coil on the receiving coil layer 400 are planar helical coils. The resonant coil and the receiving coil are wound in opposite directions, so that the magnetic flux generated by them in the first magnetic core layer 300 is in the same direction.

[0023] In this embodiment, the receiving coil assembly adopts a five-layer composite structure, further including a second magnetic core layer 100. The resonant coil layer 200 is disposed between the first magnetic core layer 300 and the second magnetic core layer 100. The five-layer composite structure, from the side furthest from the transmitting coil to the side closest to the transmitting coil, consists of: the second magnetic core layer 100, the resonant coil layer 200, the first magnetic core layer 300, the receiving coil layer 400, and the insulating protective layer 500. The first magnetic core layer 300 is a double-sided multiplexed magnetic core, and the first magnetic core layer 300 and the second magnetic core layer 100 are preferably made of manganese-zinc ferrite material. In one embodiment, the receiving coil assembly may omit the second magnetic core layer 100, forming a four-layer composite structure.

[0024] The receiver controller 600 is separately disposed from the receiver coil assembly. The receiver controller 600 includes a control module, a dynamic tuning module 620, a rectifier and filter unit 610, and an efficiency monitoring module 630. The rectifier and filter unit 610 is used to rectify and filter the circuit. The dynamic tuning module 620 is used to control and adjust the resonant frequency of the receiver. The efficiency monitoring module 630 is used to monitor the energy transmission efficiency. The receiver controller 600 is electrically connected to a load. The dynamic tuning module 620 includes a piezoelectric ceramic variable capacitor C. tune And the driving circuit.

[0025] The transmitting end adopts an LCC compensation topology, and the receiving end adopts an LCC compensation topology.

[0026] On the other hand, the present invention discloses an adaptive tuning method, which includes the following steps: S1. The receiver controller 600 monitors the current energy transmission efficiency η_cur of the wireless charging system in real time through the efficiency monitoring module 630. S2. The receiving controller 600 performs closed-loop optimization using the perturbation-observation method, applying a preset perturbation to the driving voltage of the piezoelectric ceramic variable capacitor Ctune to adjust the equivalent capacitance value of the parallel resonant branch. S3. Repeat S1 and S2 to enable the wireless charging system to dynamically track and maintain near the point of maximum efficiency when the coupling coefficient changes due to the change in the pose of the receiver.

[0027] In S2, S2 specifically includes the following steps: S2.1. Using the current driving voltage V_cur of the piezoelectric ceramic variable capacitor as a reference, and the current energy transfer efficiency η_cur, apply a positive voltage perturbation ΔV, and measure the energy transfer efficiency η_pos after the perturbation. S2.2 Determine whether η_pos is greater than η_cur + δ, where δ is greater than the preset efficiency threshold for measuring system noise; if so, accept a positive disturbance + ΔV, update V_cur and η_cur, keep ΔV unchanged, and return to S1; otherwise, apply a negative disturbance - ΔV and measure the efficiency η_neg after the disturbance. S2.3. Determine if η_neg is greater than η_cur + δ. If so, accept the negative perturbation, update V_cur and η_cur, keep ΔV unchanged, and return to S1. Otherwise, reduce the step size by half. ΔV1 = ΔV / 2; Where ΔV1 is the updated step size; S2.4 Determine whether ΔV1 is greater than the minimum step size ΔV_min. If so, return to S1 to continue iterating; otherwise, maintain the current driving voltage V_cur.

[0028] It also includes anomaly handling steps: if the efficiency monitoring module 630 detects that the energy transmission efficiency η_cur is lower than the preset safety threshold η0 and cannot be recovered after multiple optimization attempts, it is determined to be a system anomaly, and the transmission power is automatically reduced and an alarm signal is issued; if the anomaly continues for more than a set time t, charging is stopped.

[0029] The receiver controller internally includes a full-bridge rectifier + LC filter unit, a series compensation capacitor C2, and a parallel compensation capacitor C. f2 Piezoelectric ceramic variable capacitor C tune The high-voltage drive circuit and microcontroller include a receiving coil layer 400 serving as the receiving coil L2 and a resonant coil layer 200 serving as the receiving end parallel resonant inductor L. f2 Used with parallel compensation capacitor C f2 The series connection forms a parallel resonant branch, and the piezoelectric ceramic variable capacitor C tune Parallel connection in parallel compensation capacitor C f2 The two ends are used to form an adjustable parallel resonant branch.

[0030] The transmitting end includes a transmitting resonant inductor, a transmitting coil, a transmitting series compensation capacitor, and a transmitting parallel compensation capacitor. The transmitting coil is coupled to the receiving coil of the receiving coil layer. The transmitting end is configured to operate at a fixed frequency, and the dynamic tuning module of the receiving end is configured to actively adjust the resonant frequency of the parallel resonant branch to match the operating frequency of the transmitting end.

[0031] like Figure 5 As shown, the equivalent circuit of the receiving end is: the receiving coil L2 is connected in series with the series compensation capacitor C2 (equivalent node A); the parallel compensation capacitor C... f2 One end is connected to L2, and the other end is connected to the resonant coil layer (as L). f2 The piezoelectric ceramic variable capacitor C is connected in series with a rectifier circuit. tune Parallel connection to the receiving parallel compensation capacitor C f2 The two ends form an adjustable parallel resonant branch.

[0032] It is important to note that there is an inseparable synergistic relationship between the method of this invention and the aforementioned receiving coil assembly structure: Because the first magnetic core layer 300 in the double-sided multiplexed structure effectively shields the resonant coil layer 200 (unintended coupling coefficient k ≤ 0.025), the tuning of the parallel resonant branch does not cause significant changes in the main mutual inductance parameters. If a same-side integrated structure is used, the tuning will lead to additional mutual inductance drift, causing misjudgments or oscillations in the perturbation observation method, preventing stable convergence. Therefore, the structure of this invention provides the prerequisite for stable algorithm operation, while the algorithm amplifies the efficiency recovery benefits of the structure in anti-offset scenarios; the two are interdependent and synergistically enhance each other.

[0033] In this embodiment, the system parameters are designed as follows: a two-sided LCC topology is used, and the operating frequency is 85kHz. Based on the fundamental properties of the two-sided LCC topology, the requirements are: Transmitter: L1=75μH, L f1 =23.1μH, C1=67nF, C f1 =153nF.

[0034] Receiver end: Receiver coil L2=53μH, C2=107nF, C f2 =175nF, resonant coil layer 200, L f2 Design value 20μH.

[0035] piezoelectric ceramic variable capacitor C tune Parallel to C f2 At both ends, the capacitance value can be adjusted from 5 to 20 nF, and the equivalent parallel capacitance is adjustable from 155 to 195 nF.

[0036] Fabrication of the receiving coil assembly: The five-layer composite structure, from bottom to top, consists of: Second core layer 100: PC95 ferrite, 1.0mm thick, 35mm×35mm in size.

[0037] Resonant coil layer 200: 0.1mm×100 strands of Litz wire, wound 25 turns clockwise, embedded in FR-4 substrate, thickness 0.8mm.

[0038] The first magnetic core layer 300 is made of PC95 ferrite with a thickness of 1.0 mm and a size of 35 mm × 35 mm. A local opening 310 with a width of 1.5 mm and a depth of 0.4 mm is formed to adjust Lf2 from 35 μH to 20 μH.

[0039] The receiving coil layer 400 consists of 0.1mm × 100 strands of Litz wire, wound counterclockwise for 14 turns, with a thickness of 0.8mm and an inductance of 53μH. The two coils are wound in opposite directions, and their magnetic fluxes are superimposed in the same direction.

[0040] Insulating protective layer 500: Polyimide film, 0.2mm thick.

[0041] The layers are bonded with epoxy structural adhesive and cured under pressure and heat, with a total thickness of approximately 4.0 mm.

[0042] Receiver Controller: The receiver controller 600 is arranged separately from the coil assembly and connected via an FPC. Internally, it includes: a full-bridge rectifier + LC filter unit, a series compensation capacitor C2, and a parallel compensation capacitor C. f2 Piezoelectric ceramic variable capacitor C tune High-voltage drive circuit and microcontroller, dynamic tuning is achieved by observing the running disturbance.

[0043] Magnetic shielding effect verification: Within the range of 5mm vertical distance, 0-15mm horizontal offset, and 0-15° angular offset, the unexpected coupling coefficient k between the resonant coil layer 200 and the transmitting coil was measured using an LCR bridge to be ≤0.025, which is much lower than the main power coupling coefficient, proving that crosstalk is effectively suppressed.

[0044] Dynamic tuning experiment: Transmit power 500W, transmission distance 10mm, initial alignment efficiency 92.5%.

[0045] Horizontal offset 10mm: Untuned efficiency 41.8%, Tuned efficiency 88.3%; Angle offset of 10°: Untuned efficiency 59.2%, tuned efficiency 86.7%.

[0046] Experiments show that structural decoupling and algorithm optimization have a significant synergistic effect, and the anti-misalignment capability is significantly improved.

[0047] Those skilled in the art can make reasonable modifications to the concept of this invention, including but not limited to: adjusting the operating frequency to 85kHz / 150kHz, changing the power level, omitting the second magnetic core layer 100 to form a simplified four-layer structure, etc., all of which fall within the protection scope of this invention.

[0048] Finally, it should be emphasized that the above description is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse, the method being used in a wireless charging system comprising a transmitter and a receiver coupled to the transmitter, the receiver comprising a receiver coil assembly and a receiver controller (600), the receiver controller (600) comprising a control module, a dynamic tuning module (620), a rectifier filter unit (610), and an efficiency monitoring module (630), characterized in that, The receiving coil assembly includes a resonant coil layer (200), a first magnetic core layer (300), a receiving coil layer (400), and an insulating protective layer (500) arranged sequentially. The receiving coil layer (400) and the resonant coil layer (200) are respectively disposed on opposite sides of the first magnetic core layer (300). The resonant coil layer (200) is disposed away from the transmitting end, and the receiving coil layer (400) is disposed towards the transmitting end. The first magnetic core layer (300) forms a magnetic shield for the resonant coil layer (200). The receiving controller (600) is electrically connected to the resonant coil layer (200) and the receiving coil layer (400) respectively. The method includes the following steps: S1. The receiver controller (600) monitors the current energy transmission efficiency η_cur of the wireless charging system in real time through the efficiency monitoring module (630); S2. The receiving controller (600) performs a disturbance-observation closed-loop optimization on the piezoelectric ceramic variable capacitor C. tune A preset disturbance is applied to the driving voltage to adjust the equivalent capacitance value of the parallel resonant branch; S3. Repeat S1 and S2 to enable the wireless charging system to dynamically track and maintain near the point of maximum efficiency when the coupling coefficient changes due to the change in the pose of the receiver.

2. The adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse according to claim 1, characterized in that, In S2, S2 specifically includes the following steps: S2.

1. Using the current driving voltage V_cur of the piezoelectric ceramic variable capacitor as a reference, and the current energy transfer efficiency η_cur, apply a positive voltage perturbation ΔV, and measure the energy transfer efficiency η_pos after the perturbation. S2.2 Determine whether η_pos is greater than η_cur + δ, where δ is greater than the preset efficiency threshold for measuring system noise; if so, accept a positive disturbance + ΔV, update V_cur and η_cur, keep ΔV unchanged, and return to S1; otherwise, apply a negative disturbance - ΔV and measure the efficiency η_neg after the disturbance. S2.

3. Determine if η_neg is greater than η_cur + δ. If so, accept the negative perturbation, update V_cur and η_cur, keep ΔV unchanged, and return to S1. Otherwise, reduce the step size by half. ΔV1 = ΔV / 2; Where ΔV1 is the updated step size; S2.4 Determine whether ΔV1 is greater than the minimum step size ΔV_min. If so, return to S1 to continue iterating; otherwise, maintain the current driving voltage V_cur.

3. The adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse according to claim 2, characterized in that, It also includes an anomaly handling step. If the efficiency monitoring module (630) detects that the energy transmission efficiency η_cur is lower than the preset safety threshold η0 and cannot be recovered after multiple optimization attempts, it is determined to be a system anomaly, and the transmission power is automatically reduced and an alarm signal is issued. If the anomaly continues for more than the set time t, charging is stopped.

4. The adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse according to claim 1, characterized in that, At least one opening (310) is provided on the first magnetic core layer (300).

5. The adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse according to claim 4, characterized in that, The width of the opening (310) is 0.5 mm to 2.0 mm, and the depth of the opening (310) is 20% to 50% of the thickness of the first magnetic core layer (300).

6. The adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse according to claim 1, characterized in that, Both the resonant coil layer (200) and the receiving coil layer (400) are planar spiral coils, and the coil winding directions of the resonant coil layer (200) and the receiving coil layer (400) are opposite.

7. The adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse according to claim 1, characterized in that, The receiving coil assembly further includes a second magnetic core layer (100), and the resonant coil layer (200) is disposed between the first magnetic core layer (300) and the second magnetic core layer (100).

8. The adaptive tuning method for a wireless charging system based on double-sided magnetic core reuse according to claim 1, characterized in that, The transmitting end adopts an LCC compensation topology, and the receiving end adopts an LCC compensation topology.

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