A coplanar load-independent multi-branch constant-current constant-voltage wireless power transmission system

Abstract

The application discloses a coplanar and load-independent multi-branch constant-current constant-voltage wireless power transmission system, which comprises a high-frequency inverter power supply, an LC resonator array with soft magnetic body for enhancing magnetic coupling of adjacent coils and a plurality of loads; the LC resonator array comprises a source-end coupling coil and a common-end relay coupling coil, the common-end relay coupling coil is extended with a constant-voltage branch coil and a constant-current branch coil, the constant-voltage branch coil comprises a constant-voltage branch load-end coupling coil, the constant-current branch coil comprises a constant-current branch relay coupling coil and a constant-current branch load-end coupling coil, and double-layer soft magnetic bodies are covered on the upper and lower surfaces of the joint of adjacent coils; all the coils are connected in series with tuning capacitors for tuning the resonator to a working frequency. The application has a simple structure, each branch is independent through the common-end relay coupling inductive coil, constant-current constant-voltage output can be realized on each branch which does not affect each other, and the charging characteristics of different electric appliances are met.

Description

Technical Field

[0001] This invention belongs to the technical field of wireless power transmission systems, specifically relating to a coplanar, load-independent, multi-branch constant current and constant voltage wireless power transmission system. Background Technology

[0002] WPT (Wireless Power Transmission) technology is increasingly widely used in various fields to power electrical appliances, including electric vehicles, implantable medical devices, drones, and portable electronic devices. One of the most important applications of WPT is charging multiple loads, and one of the most prominent challenges is providing a stable output to the receiver. Achieving stable constant current and constant voltage output characteristics has become a hot research topic.

[0003] Patent CN111478458A proposes a wireless power transmission system and its constant current and constant voltage control method. It utilizes a DSP processor and a wireless power transmission device, switching between them via a switching controller, current acquisition circuit, voltage acquisition circuit, and relying on compensation networks on each receiving module to achieve constant current or constant voltage output. However, this method cannot simultaneously achieve constant current and constant voltage output, and therefore cannot simultaneously meet the needs of various electrical appliances.

[0004] Patent CN110429691A proposes a constant-current-constant-voltage charging wireless power transfer system based on half-bridge switching. By switching the conduction mode of the switching transistors in the high-frequency inverter module, constant-current-constant-voltage charging of the battery can be achieved without complex and continuous closed-loop regulation control. The literature "A Wireless Power Transfer System with Multiple Constant Current and Constant Voltage Outputs" proposes a multi-load wireless power transfer system with constant current and constant voltage outputs. Each coil adopts a series-compensated topology. In odd-numbered repeater units, the load is connected in series with two repeater coils, while in even-numbered repeater units, the load is connected in parallel with two repeater coils. Odd and even units implement constant current (CC) and constant voltage (CV) respectively. While this coil design is ingenious, it is structurally complex with many coils and does not consider the case of separate constant voltage or constant current power supply.

[0005] The common problem with these studies is that either the compensation circuit is complex, the coil structure is complex, or the multi-load system can only output constant voltage or constant current, and cannot meet the requirement of different load outputs with different load-independent characteristics. Summary of the Invention

[0006] To address the shortcomings and challenges of existing technologies, this invention aims to provide a coplanar, load-independent, multi-branch constant current and constant voltage wireless power transfer system. By using a common terminal relay coupling inductor coil to make each branch independent, constant current and constant voltage output can be achieved on each branch without interference, meeting the charging characteristics of different electrical appliances. This will greatly enhance the application prospects of coplanar WPT technology.

[0007] This invention places a double-layered soft magnet at appropriate positions on both the upper and lower surfaces of adjacent coplanar coils at their connection points. This significantly enhances the magnetic coupling between adjacent coils. By coupling the inductor coil through the common terminal, constant current and constant voltage output can be achieved simultaneously. Removing any section of the coil does not affect the charging effect of other sections, and changes in load do not affect the system's stable constant current and constant voltage output. These advantages significantly improve the practicality of coplanar wireless power transfer systems and expand their application prospects.

[0008] This invention is achieved through the following technical solution:

[0009] This invention provides a coplanar, load-independent, multi-branch constant-current and constant-voltage wireless power transfer system. It is a multi-chain coplanar WPT structure, including a high-frequency inverter power supply, an LC resonator array with soft magnetic material enhancing the magnetic coupling of adjacent coils, and multiple loads. The LC resonator array includes a source-end coupling coil and a common-end relay coupling coil. The source-end coupling coil is connected in series with the high-frequency inverter power supply. The common-end relay coupling coil extends to include constant-voltage and constant-current spur coils. The constant-voltage spur coil includes a constant-voltage spur load-end coupling coil, and the constant-current spur coil includes a constant-current spur relay coupling coil and a constant-current spur load-end coupling coil. The connection points of adjacent coils are covered with double-layered soft magnetic material on both the top and bottom surfaces. All coils are connected in series with tuning capacitors to tune the resonators to the operating frequency.

[0010] Furthermore, both the constant voltage spur coil and the constant current spur coil are configured in pairs.

[0011] Furthermore, the coil is in the shape of a low-profile planar square or planar circle.

[0012] Furthermore, the constant voltage spur load-end coupling coil is connected in series with the load and can also be used as a relay coil when extended; the constant current spur relay coupling coil is used as a relay coil, and the constant current spur load-end coupling coil is connected in series with the load.

[0013] Furthermore, the high-frequency inverter power supply is a DC-AC or AC-DC-AC power supply, and the DC-AC part of the circuit is a half-bridge inverter or a full-bridge inverter power supply.

[0014] Compared with the prior art, the beneficial effects of the present invention include:

[0015] 1. The wireless power transmission system of this invention has a simple structure. It achieves independent constant current and constant voltage outputs through a common terminal relay coupling inductor coil. Ferrite plates enhance the coupling between adjacent coils. Since each branch is independent, removing any one branch will not affect the charging effect of other branches. The voltage or current at the load end can be adjusted through the mutual inductance between the coils. This satisfies the different charging characteristics of charging devices.

[0016] 2. This invention is applicable to the design of multi-branched chain-like planar WPT systems. Attached Figure Description

[0017] Figure 1 (a) is a simplified diagram of a multi-branch constant current constant voltage WPT structure; (b) is a simplified diagram of a WPT structure with one constant voltage branch removed; (c) is a simplified diagram of a WPT structure with one constant current branch removed, where ① is the source-end emitter resonator, ② is the common-end relay resonator, and ③ is a double-layer soft magnet.

[0018] Figure 2 This is a top view of the multi-branch wireless power transfer system structure, i.e., Embodiment 1; V in the figure S As an inverter AC source, L1 is the transmitting coil inductance, L2 is the common terminal relay coil inductance, L3 and L4 are constant voltage branch receiving coil inductance, L5 and L6 are constant current branch relay coil inductance, L7 and L8 are constant current branch receiving coil inductance, C1, C2, C3, C4, C5, C6, C7, and C8 are the coil tuning capacitors, and R1, R2, R3, and R4 are a simplified external load circuit.

[0019] Figure 3 Given Figure 1 In the comparison of the magnetic fields of the system: (a) is the top view and side view of the magnetic field distribution of the multi-branch constant current and constant voltage output structure; (b) is the top view and side view of the magnetic field distribution of the system structure after removing one constant voltage branch; (c) is the top view and side view of the magnetic field distribution of the system structure after removing one constant current branch.

[0020] Figure 4 In Example 1, the voltage source V is given. S At 7.64V, assuming the load voltage on Coil3 is V1, the load voltage on Coil4 is V2, the load current on Coil7 is I1, and the load current on Coil8 is I2, the voltage (V)-current (I)-load (Ω) curves show that the voltage and current remain basically constant over a wide range of load variations. For example, when the resistances R1 and R2 at the load terminals of the constant voltage branch vary from 30Ω to 120Ω, the voltage variation does not exceed 10%, and when the resistances R3 and R4 at the load terminals of the constant current branch vary from 1Ω to 30Ω, the current variation does not exceed 10%. This verifies that the multi-branch WPT system meets the constant current and constant voltage characteristics.

[0021] Figure 5 Example 2: Top view of the system model structure with one constant pressure support removed;

[0022] Figure 6 In Example 2, the voltage source V S At 7.64V, assuming the load voltage on Coil3 is V1, the load voltage on Coil4 is V2, the load current on Coil7 is I1, and the load current on Coil8 is I2, the voltage (V)-current (I)-load (Ω) curves show that the voltage and current remain basically constant over a wide range of load variations. For example, when the resistance R2 at the load end of the constant voltage branch varies from 30Ω to 120Ω, the voltage change does not exceed 10%. When the resistances R3 and R4 at the load end of the constant current branch vary from 1Ω to 30Ω, the current change does not exceed 10%. This verifies that removing one constant voltage branch allows the multi-branch WPT system to meet the constant current and constant voltage characteristics.

[0023] Figure 7 Example 3: Top view of the system structure with one constant current spur removed;

[0024] Figure 8 In Example 3, the voltage source V S At 7.64V, assuming the load voltage on Coil3 is V1, the load voltage on Coil4 is V2, the load current on Coil7 is I1, and the load current on Coil8 is I2, the voltage (V)-current (I)-load (Ω) curves show that the voltage and current remain basically constant over a wide range of load variations. For example, when the constant voltage branch load terminal resistances R1 and R2 vary from 30Ω to 120Ω, the voltage variation does not exceed 10%, and when the constant current branch load terminal resistance R4 varies from 1Ω to 30Ω, the current variation does not exceed 10%. This verifies that removing one constant current branch allows the multi-branch WPT system to meet the constant current and constant voltage characteristics.

[0025] Figure 9 The figure shows the efficiency curves of the multi-branch WPT system under three implementation scenarios. As can be seen from the figure, the efficiency curve of Implementation 1, i.e., the output of two constant current and constant voltage branches, has a maximum efficiency η of 92.06%. Implementation 2, i.e., the multi-branch WPT system with one constant voltage branch removed, has a maximum efficiency η of 92.91%. Implementation 3, i.e., the multi-branch WPT system with one constant current branch removed, has a maximum efficiency η of 93.26%. The efficiency variation range of Implementation 1, 2, and 3 is not large, and the curve trends are similar. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings.

[0027] The structure of a multi-branch constant current constant voltage wireless power transfer system is as follows: Figure 1 As shown in (a), it is a multi-channel chain-like coplanar WPT structure. The coils are typically low-profile planar square or planar circular coils of the same specification. ① The source-end emitter resonator, ② the common-end relay resonator, and ③ are double-layer soft magnetic materials. The series tuning capacitors of all coils tune the resonator to the operating frequency, i.e. The operating frequency is determined by requirements, typically ranging from tens of kHz to tens of MHz. Power supply V S It is derived from a DC-AC or AC-DC-AC circuit conversion, with the DC-AC section being a half-bridge or full-bridge inverter power supply. The load at the receiving end consists of the device to be charged and functional circuits such as rectification, filtering, and matching; in this embodiment, it is simplified to a pure resistor.

[0028] Repeater coils can not only extend the transmission distance of wireless power transmission systems, but also act as a common repeater to separate various branches. They can not only achieve constant current or constant voltage output, but also make each branch independent of the others and not affect each other.

[0029] Figure 2 The overall system structure diagram is given. Coil1 is the transmitting resonator connected in series with the high-frequency inverter power supply; Coil2 serves as a common-terminal relay resonator; Coil3 and Coil4 are receiving resonators connected in series with the load, and can also be used as relay resonators for extension; Coil5 and Coil6 are relay resonators; and Coil7 and Coil8 are receiving resonators connected in series with the load. R1 and R2 are the constant-voltage stub load resistors, R3 and R4 are the constant-current stub load resistors, and C1-C8 are tuning capacitors. Calculations and analysis based on the circuit diagram show that the current in the constant-voltage stub is I3 = -V. S M 23 / (R1M 12 ), I4 = -V S M 24 / (R2M 12 According to the formula, the voltage of the constant voltage stub is independent of the load resistance, and only depends on the voltage source voltage, the mutual inductance between Coil2 and Coil3 or Coil2 and Coil4, and the mutual inductance between Coil1 and Coil2. The current of the constant current stub is I5 = -jV. S M 25 / (ωM 12 M 57 ), I6=-jV S M 26 / (ωM 12 M 68According to the formula, the current in the constant current branch is only related to the voltage source voltage, the mutual inductance between Coil2 and Coil6 or Coil2 and Coil5, the mutual inductance between Coil1 and Coil2, and the mutual inductance between Coil5 and Coil7 or Coil6 and Coil8, and is independent of the load resistance. Therefore, it can be seen that the magnitude of the load's output voltage or current can be adjusted by setting the mutual inductance of the coils, regardless of the load size.

[0030] Figure 1 (a) A simplified diagram of a WPT system with two constant voltage output branches and two constant current output branches is given. Based on... Figure 4 The simulation results of the voltage (V)-current (I)-load (Ω) curves show that when the loads of the two constant current branches are fixed at R3 = R4 = 15Ω, the voltage output amplitudes of the two constant current branches are the same and the voltage changes within 10% as the load resistance of the constant voltage branch increases, which meets the characteristics of constant voltage output. When the loads of the two constant voltage output branches are fixed at R1 = R2 = 30Ω, the current outputs of the two constant current load branches are the same and the current changes within 10% as the load of the constant current branch increases, which meets the characteristics of constant current output. This verifies that the output voltage or output current of each branch is independent of the load.

[0031] To ensure that removing or adding branches does not affect the overall efficiency of the WPT system Figure 5 The system block diagram after removing one constant voltage output stub is given. (Refer to...) Figure 6 Through simulation results of the voltage (V)-current (I)-load (Ω) curves, it can be observed from the graph that when the loads of the two constant current branches are fixed at R3 = R4 = 15Ω, as the load at the constant voltage branch continuously increases, the voltage output amplitude at the load terminal of the constant voltage branch is related to... Figure 4 The comparisons are roughly the same, and the voltage variation is within 10%, satisfying the constant voltage output characteristic. When the load R2 of the fixed constant voltage output branch is 30Ω, as the load at the constant current terminal continuously increases, the current output amplitude at the two constant current load terminals is similar to... Figure 4 The results are roughly the same, and the current variation is within 10%, which meets the characteristics of constant current output. Further comparison... Figure 9 As can be seen from Examples 1 and 2, the overall efficiency of the WPT system does not change significantly. This satisfies the assumption that removing a constant-pressure stub does not affect the entire WPT system.

[0032] Figure 7 The system block diagram of the WPT system with a constant current stub removed is given, referring to... Figure 8Through simulation results of the voltage (V)-current (I)-load (Ω) curves, it can be observed from the graph that when the load R4 of the fixed constant current branch is 15Ω, as the load terminal resistance of the two constant voltage branches continuously increases, the voltage output amplitude of the load terminals of the two constant voltage branches is related to... Figure 4 The components are roughly the same, and the voltage variation is within 10%, satisfying the characteristics of constant voltage output. When the loads of the two constant voltage output branches are fixed at R1 = R2 = 30Ω, as the load resistance at the constant current terminal continuously increases, the current output amplitude at the constant current load terminal is relatively similar. Figure 4 They are roughly the same, and the current variation is within 10%, which meets the characteristics of constant current output. Then compare... Figure 9 As can be seen from Examples 1 and 3, the overall efficiency of the WPT system does not change significantly. This satisfies the assumption that removing a constant current branch does not affect the entire WPT system.

[0033] Example 1: Wireless Power Transfer System with Multi-Branch Constant Current and Constant Voltage Output

[0034] The system is like Figure 2 As shown, the system consists of 5 large circular coils, 3 small circular coils, and 8 ferrite pieces. Each ferrite piece is composed of 5 Mn-Zn ferrite (PC40) pieces with dimensions of 90mm*15mm*5mm, placed vertically between the resonator coils. The Litz wire coils have a diameter of 3.1mm. Both the large and small circular coils are double-wound, with the large coil having an outer diameter Φ = 200mm and an inner diameter of... Number of turns n = 8, coil internal resistance is 0.39Ω; outer diameter of small coil Φ = 100mm, inner diameter The number of turns n = 10, the coil internal resistance is 0.289Ω, and the resonant frequency of the entire system is set to 100kHz. The entire system includes the power supply V. S The circuit consists of: source-end coupling coil L1, source-end tuning capacitor C1, common-end relay coupling coil L2, common-end relay tuning capacitor C2, constant-voltage spur load-end coupling coil L3, constant-voltage spur load-end tuning capacitor C3, constant-voltage spur load-end coupling coil L4, constant-voltage spur load-end tuning capacitor C4, constant-current spur relay coupling coil L5, constant-current spur relay tuning capacitor C5, constant-current spur relay coupling coil L6, constant-current spur relay tuning capacitor C6, constant-current spur load-end coupling coil L7, constant-current spur load-end tuning capacitor C7, constant-current spur load-end coupling coil L8, constant-current spur load-end tuning capacitor C8, and R1, R2, R3, and R4 forming a simplified external load circuit.

[0035] Its source-end coupling coil inductance L1 = 46.2 μH, source-end tuning capacitor C1 = 54.83 nF, common-end relay coupling coil inductance L2 = 334.3 μH, common-end relay tuning capacitor C2 = 7.58 nF, constant-voltage branch load-end coupling coil inductance L3 = 222.3 μH, constant-voltage branch load-end tuning capacitor C3 = 11.39 nF, constant-voltage branch load-end coupling coil inductance L4 = 219.3 μH, constant-voltage branch load-end tuning capacitor C4 = 11.55 nF, constant-current branch... The inductance of the relay coupling coil in the constant current branch is L5 = 219.3 μH, the tuning capacitor of the constant current branch relay is C5 = 11.55 nF, the inductance of the relay coupling coil in the constant current branch is L6 = 223.1 μH, the tuning capacitor of the constant current branch relay is C6 = 11.35 nF, the inductance of the load-side coupling coil in the constant current branch is L7 = 48 μH, the tuning capacitor of the load-side coupling coil in the constant current branch is C7 = 52.77 nF, the inductance of the load-side coupling coil in the constant current branch is L8 = 47.6 μH, and the tuning capacitor of the load-side coupling coil in the constant current branch is C8 = 53.21 nF. Its magnetic field distribution diagram is as follows: Figure 3 As shown in (a).

[0036] Will Figure 4 and Figure 9 The analysis clearly shows that the various branches are independent of each other. When the voltage source Vs = 7.64V, and the fixed constant current branch loads R3 = R4 = 15Ω and the fixed constant voltage branch loads R1 = R2 = 30Ω, the voltage (V)-current (I)-load (Ω) curves show that the voltage and current remain essentially constant over a wide range of load variations. For example, when the resistances R1 and R2 at the constant voltage branch load terminals vary from 30Ω to 120Ω, the voltage change does not exceed 10%, and when the resistances R3 and R4 at the constant current branch load terminals vary from 1Ω to 30Ω, the current change does not exceed 10%. This verifies the characteristic that the multi-branch constant current and constant voltage output is independent of the load.

[0037] Example 2: WPT system with one constant pressure support removed

[0038] The WPT structure is shown in the example below. Figure 5 As shown. This structure is based on Example 1 without one Coil 3, and consists of 4 large circular coils, 3 small circular coils, and 6 ferrite pieces. Each ferrite piece is composed of 5 Mn-Zn ferrite (PC40) pieces with dimensions of 90mm*15mm*5mm, placed vertically between the resonator coils. The Litz wire coil has a diameter of 3.1mm. Both the large and small circular coils are double-wound, with the outer diameter of the large coil being Φ = 200mm and the inner diameter being... Number of turns n = 8, coil internal resistance is 0.39Ω; outer diameter of small coil Φ = 100mm, inner diameter The number of turns n = 10, and the coil internal resistance is 0.289Ω. The resonant frequency of this system is 100kHz. The entire system includes the power supply V. S The circuit consists of: source-end coupling coil L1, source-end tuning capacitor C1, common-end relay coupling coil L2, common-end relay tuning capacitor C2, constant-voltage spur load-end coupling coil L4, constant-voltage spur load-end tuning capacitor C4, constant-current spur relay coupling coil L5, constant-current spur relay tuning capacitor C5, constant-current spur relay coupling coil L6, constant-current spur relay tuning capacitor C6, constant-current spur load-end coupling coil L7, constant-current spur load-end tuning capacitor C7, constant-current spur load-end coupling coil L8, constant-current spur load-end tuning capacitor C8, and R1, R2, R3, and R4 forming a simplified external load circuit.

[0039] Its source-end coupling coil inductance L1 = 47.7 μH, source-end tuning capacitor C1 = 53.1 nF, common-end relay coupling coil inductance L2 = 255.6 μH, common-end relay tuning capacitor C2 = 9.9 nF, constant-voltage spur load-end coupling coil inductance L4 = 221 μH, constant-voltage spur load-end tuning capacitor C4 = 11.46 nF, constant-current spur relay coupling coil inductance L5 = 222.5 μH, constant-current spur... The following parameters are given: tuning capacitor C5 = 11.38 nF, constant current branch relay coupling coil inductance L6 = 228 μH, constant current branch relay tuning capacitor C6 = 11.11 nF, constant current branch load terminal coupling coil inductance L7 = 48.8 μH, constant current branch load terminal tuning capacitor C7 = 51.9 nF, constant current branch load terminal coupling coil inductance L8 = 47.8 μH, and constant current branch load terminal tuning capacitor C8 = 52.99 nF. The magnetic field distribution diagram is shown below. Figure 3 As shown in (b).

[0040] Figure 6 The voltage (V)-current (I)-load (Ω) curves of the system are presented. The graph shows that the voltage and current remain essentially constant over a wide range of load variations. For example, when the load terminal resistance R2 of the constant voltage branch varies from 30Ω to 120Ω, the voltage change is less than 10%. Similarly, when the load terminal resistances R3 and R4 of the constant current branch vary from 1Ω to 30Ω, the current change is less than 10%. This verifies the load-independent characteristic of the multi-branch constant current and constant voltage output. (Refer to...) Figure 4 It can be seen that removing a constant voltage stub has little effect on the voltage and current of the entire system. Figure 9 It can be seen that the impact on system efficiency is not significant, verifying the characteristics of the multi-branch constant current and constant voltage output that each branch is independent, does not affect each other, and can be designed independently.

[0041] Example 3: WPT system with one constant current stub removed

[0042] The WPT structure is shown in the example below. Figure 7 As shown. This structure is based on Example 1, except for Coil 5 and Coil 7. It consists of four large circular coils, two small circular coils, and six ferrite pieces. Each ferrite piece is composed of five Mn-Zn ferrite (PC40) pieces measuring 90mm*15mm*5mm, placed vertically between the resonator coils. The Litz wire coil has a diameter of 3.1mm. Both the large and small circular coils are double-wound, with the outer diameter of the large coil being Φ = 200mm and the inner diameter being... Number of turns n = 8, coil internal resistance is 0.39Ω; outer diameter of small coil Φ = 100mm, inner diameter The number of turns n = 10, and the coil internal resistance is 0.289Ω. The resonant frequency of this system is 100kHz. The entire system includes the power supply V. S The circuit consists of: source-end coupling coil L1, source-end tuning capacitor C1, common-end relay coupling coil L2, common-end relay tuning capacitor C2, constant-voltage spur load-end coupling coil L3, constant-voltage spur load-end tuning capacitor C3, constant-voltage spur load-end coupling coil L4, constant-voltage spur load-end tuning capacitor C4, constant-current spur relay coupling coil L6, constant-current spur relay tuning capacitor C6, constant-current spur load-end coupling coil L8, and constant-current spur load-end tuning capacitor C8. R1, R2, and R4 form a simplified external load circuit.

[0043] Its source-end coupling coil inductance L1 = 48.3 μH, source-end tuning capacitor C1 = 52.44 nF; common-end relay coupling coil inductance L2 = 280.6 μH, common-end relay tuning capacitor C2 = 9.03 nF; constant-voltage spur load-end coupling coil inductance L3 = 224.3 μH, constant-voltage spur load-end tuning capacitor C3 = 11.29 nF; constant-voltage spur load-end coupling coil inductance L4 = 229.8 μH, constant-voltage spur load-end tuning capacitor C4 = 11.02 nF; constant-current spur relay coupling coil inductance L6 = 229.8 μH, constant-current spur relay tuning capacitor C6 = 11.02 nF; constant-current spur load-end coupling coil inductance L8 = 48.6 μH, constant-current spur load-end tuning capacitor C8 = 52.12 nF. Its magnetic field distribution diagram is as follows: Figure 3 As shown in (c).

[0044] Figure 8 The voltage (V)-current (I)-load (Ω) curves of the system are presented. The graph shows that the voltage and current remain essentially constant over a wide range of load variations. For example, when the load terminal resistances R1 and R2 of the constant voltage branch vary from 30Ω to 120Ω, the voltage change does not exceed 10%. Similarly, when the load terminal resistance R4 of the constant current branch varies from 1Ω to 30Ω, the current change does not exceed 10%. This verifies the load-independent characteristic of the multi-branch constant current and constant voltage output. (Refer to...) Figure 4It can be seen that removing a constant current branch has little impact on the voltage and current of the entire system. Figure 9 It can be seen that the impact on system efficiency is not significant, verifying the characteristics of the multi-branch constant current and constant voltage output that each branch is independent, does not affect each other, and can be designed independently.

[0045] The above description merely illustrates preferred embodiments of the present invention, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications, improvements, and substitutions without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A coplanar, load-independent, multi-branch constant current and constant voltage wireless power transfer system, characterized in that: It is a multi-chain coplanar WPT structure, including a high-frequency inverter power supply, an LC resonator array with soft magnetic material enhancing the magnetic coupling of adjacent coils, and multiple loads. The LC resonator array includes a source-end coupling coil and a common-end relay coupling coil. The source-end coupling coil is connected in series with the high-frequency inverter power supply. The common-end relay coupling coil extends to include constant-voltage spur coils and constant-current spur coils. The constant-voltage spur coil includes a constant-voltage spur load-end coupling coil, and the constant-current spur coil includes a constant-current spur relay coupling coil and a constant-current spur load-end coupling coil. The connection between adjacent coils is covered with double-layer soft magnetic material on both the top and bottom surfaces. The carrier-end coupling coil is connected in series with the load and can also be used as a relay coil when extended; the constant current branch relay coupling coil is used as a relay coil, and the constant current branch load-end coupling coil is connected in series with the load; all coils are connected in series with a tuning capacitor to tune the resonator to the operating frequency; there are two constant voltage branch coils and two constant current branch coils. Removing one constant voltage branch coil or one constant current branch coil will result in a voltage and current change of the load output within 10%, satisfying the constant current and constant voltage output characteristics. The multi-branch constant current and constant voltage output is independent of the load, and each branch of the multi-branch constant current and constant voltage output is independent of each other and does not affect each other.

2. The coplanar, load-independent, multi-branch constant current and constant voltage wireless power transfer system according to claim 1, characterized in that: The coil is in the shape of a low-profile planar square or planar circle.

3. The coplanar, load-independent, multi-branch constant current and constant voltage wireless power transfer system according to claim 1, characterized in that: The high-frequency inverter power supply is a DC-AC or AC-DC-AC power supply, and the DC-AC part of the circuit is a half-bridge or full-bridge inverter power supply.

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