Compensation circuit structure for wireless charging coil with large offset

Abstract

The present invention belongs to the field of wireless charging technology, and specifically relates to a compensation circuit structure of a wireless charging coil. A compensation circuit structure suitable for a wireless charging coil with large offset includes: a power input terminal; a primary circuit with a primary coil; a secondary circuit with a secondary coil; the primary circuit includes at least two groups of primary coil groups, each group of primary coil groups includes: a primary coil, which is connected in series with a compensation element to form a resonant circuit; an auxiliary coil, which is connected in parallel with an auxiliary compensation element to form an auxiliary resonant circuit; the resonant circuit is connected to the power input terminal in series with the auxiliary resonant circuit, and both the primary coil and the auxiliary coil are magnetically coupled with the secondary coil. The present invention can realize a wide range of wireless charging scenarios by expanding multiple groups of primary coil groups. During the wireless charging process, the secondary coil can realize automatic switching of adjacent primary coil groups under large offset conditions, greatly improving the power transmission efficiency under a large offset range.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless charging, and in particular relates to a compensation circuit structure of a wireless charging coil. Background Art

[0002] Wireless charging technology originates from wireless power transmission technology and can be divided into two types: low-power wireless charging and high-power wireless charging. Low-power wireless charging usually adopts electromagnetic induction, while high-power wireless charging usually adopts resonance. Most electric vehicles use resonance charging, and usually the power supply equipment transmits energy to the power-consuming device. Since the power supply equipment and the power-consuming device transmit energy through the magnetic field, there is no need for wires to connect the two, so the power supply equipment and the power-consuming device can have no exposed conductive contacts.

[0003] Wireless charging technology includes many methods, among which the electromagnetic induction method includes a primary coil and a secondary coil. The primary coil has an alternating current of a certain frequency, and a certain current is generated in the secondary coil through electromagnetic induction, thereby transferring energy from the transmitting end to the receiving end. At present, the most common charging solution adopts electromagnetic induction. In order to expand the wireless charging range, the existing wireless charging circuit will set two or more primary coils in the primary circuit part. When the secondary coil moves from one primary coil to another, the power transmission efficiency is particularly low in this large offset scenario. And during the offset process, the current of the original working primary coil is very large, which can easily damage the entire wireless charging circuit. Summary of the invention

[0004] The present invention aims to solve the technical problems of low power transmission efficiency and easy circuit damage when a secondary coil moves from one primary coil to another in an electromagnetic induction wireless charging circuit, and aims to provide a compensation circuit structure suitable for a wireless charging coil with a large offset.

[0005] A compensation circuit structure suitable for a wireless charging coil with large offset, comprising: a power input terminal; a primary circuit having a primary coil; a secondary circuit having a secondary coil;

[0006] The primary circuit includes at least two groups of primary coil groups, and each group of the primary coil groups includes:

[0007] The primary coil is connected in series with the compensation element to form a resonant circuit;

[0008] an auxiliary coil connected in parallel with the auxiliary compensation element to form an auxiliary resonant circuit;

[0009] The resonant circuit is connected in series with the auxiliary resonant circuit and then connected to the power input terminal. Both the primary coil and the auxiliary coil are magnetically coupled with the secondary coil.

[0010] The compensation element is a compensation capacitor, and the auxiliary compensation element is an auxiliary compensation capacitor.

[0011] The auxiliary coil resonates with the auxiliary compensation element at the switching frequency, that is:

[0012]

[0013] Where ω is the operating angular frequency, ω=2πf, f is the operating frequency, L a1 is the self-inductance of the auxiliary coil, C a1 is the capacitance value of the auxiliary compensation element.

[0014] The primary coil resonates with the compensation element and the auxiliary compensation element at the switching frequency, that is:

[0015]

[0016] Wherein, ω is the operating angular frequency, ω=2πf, f is the operating frequency, L1 is the self-inductance of the primary coil, C1 is the capacitance value of the compensation element, C a1 is the capacitance value of the auxiliary compensation element.

[0017] There is magnetic field coupling between the primary coils and the auxiliary coils in two adjacent primary coil groups.

[0018] When two adjacent groups of the primary coil groups are located on the same layer structure, the auxiliary coils are all located inside the corresponding primary coils, and the primary coils in the two adjacent groups have a preset distance.

[0019] When two adjacent groups of primary coils are located on different layer structures, the auxiliary coils are located above or below the corresponding primary coils, and one group of primary coils is located above or below the other group of primary coils.

[0020] When the same group of primary coil groups are on the same layer structure and two adjacent groups of primary coil groups are on different layer structures, the auxiliary coils are all located on the inner side of the corresponding primary coils, and one group of primary coils is located above or below the other group of primary coils.

[0021] When the primary coil groups of the same group are on different layer structures and two adjacent primary coil groups are on the same layer structure, the auxiliary coils are located above or below the corresponding primary coils, and the primary coils in the two adjacent groups have a preset distance.

[0022] There is decoupling between the primary coils and the auxiliary coils in two adjacent groups of primary coils.

[0023] The primary coil and the auxiliary coil in the same group are decoupled by partially overlapping the coils.

[0024] The primary coils in two adjacent groups are decoupled by partially overlapping the coils.

[0025] The auxiliary coils in two adjacent groups have a preset distance.

[0026] The positive progressive effect of the present invention is that the present invention adopts a compensation circuit structure suitable for wireless charging coils with large offsets, and can realize a large-range wireless charging scenario by expanding multiple groups of primary coil groups to cover a larger wireless charging range. During the wireless charging process, the secondary coil can realize automatic switching of adjacent primary coil groups under large offset conditions, greatly improving the power transmission efficiency under a large offset range. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a circuit structure of the present invention;

[0028] Figure 2 A coil structure of the present invention;

[0029] Figure 3 This is another coil structure of the present invention. DETAILED DESCRIPTION

[0030] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific illustrations.

[0031] Reference Figure 1 A compensation circuit structure suitable for a wireless charging coil with a large offset includes: a power input terminal, a primary circuit 100 and a secondary circuit 200.

[0032] The power input terminal (not shown) is connected to the primary circuit 100 to supply power to the primary circuit 100. The power input to the power input terminal is preferably a high-frequency power supply.

[0033] The secondary circuit 200 has a secondary coil W3 , the self-inductance of the secondary coil W3 is L3 , and the secondary circuit 200 can be connected to an electrical device via a compensation circuit (not shown).

[0034] The primary circuit 100 includes at least two groups of primary coil groups, each of which includes a primary coil and an auxiliary coil, and both the primary coil and the auxiliary coil are magnetically coupled with the secondary coil. The primary coil and the compensation element are connected in series to form a resonant circuit; the auxiliary coil and the auxiliary compensation element are connected in parallel to form an auxiliary resonant circuit; the resonant circuit and the auxiliary resonant circuit are connected in series to the power input terminal. Among them, the compensation element is a compensation capacitor, and the auxiliary compensation element is an auxiliary compensation capacitor.

[0035] Reference Figure 1 The primary circuit 100 includes two adjacent primary coil groups, one of which includes a primary coil W1, an auxiliary coil Wa1, a compensation capacitor and an auxiliary compensation capacitor. The self-inductance of the primary coil W1 is L1, and the self-inductance of the auxiliary coil Wa1 is L a1 The capacitance value of the compensation capacitor is C1, and the capacitance value of the auxiliary compensation capacitor is C a1 The other primary coil group includes the primary coil W2, the auxiliary coil Wa2, the compensation capacitor and the auxiliary compensation capacitor. The self-inductance of the primary coil W2 is L2, and the self-inductance of the auxiliary coil Wa2 is L a2 The capacitance value of the compensation capacitor is C2, and the capacitance value of the auxiliary compensation capacitor is C a2 .but:

[0036] The auxiliary coil Wa1 resonates with the auxiliary compensation element at the switching frequency, that is:

[0037]

[0038] Where ω is the operating angular frequency, ω=2πf, f is the operating frequency, L a1 is the self-inductance of the auxiliary coil Wa1, C a1 is the capacitance value of the auxiliary compensation element.

[0039] The primary coil W1 resonates with the compensation element and the auxiliary compensation element at the switching frequency, that is:

[0040]

[0041] Wherein, ω is the operating angular frequency, ω=2πf, f is the operating frequency, L1 is the self-inductance of the primary coil W1, C1 is the capacitance value of the compensation element corresponding to the primary coil W1, C a1 is the capacitance value of the auxiliary compensation element corresponding to the auxiliary coil Wa1.

[0042] The auxiliary coil Wa2 resonates with the auxiliary compensation element at the switching frequency, that is:

[0043]

[0044] Where ω is the operating angular frequency, ω=2πf, f is the operating frequency, L a2 is the self-inductance of auxiliary coil Wa2, C a2 is the capacitance value of the auxiliary compensation element.

[0045] The primary coil W2 resonates with the compensation element and the auxiliary compensation element at the switching frequency, that is:

[0046]

[0047] Wherein, ω is the operating angular frequency, ω=2πf, f is the operating frequency, L2 is the self-inductance of the primary coil W2, C2 is the capacitance value of the compensation element corresponding to the primary coil W2, C a2 is the capacitance value of the auxiliary compensation element corresponding to the auxiliary coil Wa2.

[0048] There can be magnetic field coupling between the primary coil W1, the auxiliary coil Wa1, the primary coil W2 and the auxiliary coil Wa2 in two adjacent primary coil groups. That is, the mutual inductance between the primary coil W1, the auxiliary coil Wa1, the primary coil W2 and the auxiliary coil Wa2 is not zero, and their coils do not overlap.

[0049] When two adjacent primary coil groups are on the same layer structure, the auxiliary coil Wa1 is located on the inner side of the primary coil W1, and the auxiliary coil Wa2 is located on the inner side of the primary coil W2. There is a preset distance between the primary coil W1 and the primary coil W2, that is, there is no overlap between the coils of the primary coil W1 and the primary coil W2.

[0050] When two adjacent primary coil groups are on different layer structures, the auxiliary coil Wa1 is located above or below the primary coil W1, the auxiliary coil Wa2 is located above or below the primary coil W2, and the primary coil W1 is located above or below the primary coil W2.

[0051] When the same group of primary coils is on the same layer structure, and two adjacent groups of primary coils are on different layers of structure, the auxiliary coil Wa1 is located inside the primary coil W1, the auxiliary coil Wa2 is located inside the primary coil W2, and the primary coil W1 is located above or below the primary coil W2. Figure 2 The coil structure shown in FIG. 1 adopts the above structure.

[0052] When the same group of primary coil groups are on different layer structures and two adjacent groups of primary coil groups are on the same layer structure, the auxiliary coil Wa1 is located above or below the primary coil W1, and the auxiliary coil Wa2 is located above or below the primary coil W2. There is a preset distance between the primary coil W1 and the primary coil W2, that is, there is no overlap between the coils of the primary coil W1 and the primary coil W2.

[0053] There can also be decoupling between the primary coils and the auxiliary coils in two adjacent primary coil groups. There is no magnetic field coupling between the two primary coils and the two auxiliary coils, that is, the mutual inductance between the primary coil W1, the auxiliary coil Wa1, the primary coil W2 and the auxiliary coil Wa2 is zero.

[0054] Reference Figure 3, the primary coil and the auxiliary coil in the same group are decoupled by partially overlapping the coils. The primary coils in two adjacent groups are decoupled by partially overlapping the coils. The auxiliary coils in two adjacent groups have a preset distance so that the mutual inductance between the two can be ignored.

[0055] Embodiment 1:

[0056] Reference Figure 1 and Figure 3 In the two adjacent primary coil groups of the primary circuit 100, the primary coils W1 and W2 in the two adjacent primary coil groups are designed as the main power transmitting coils, and the auxiliary coils Wa1 and Wa2 are used to generate gradually increasing impedance in the primary coils W1 or W2 when the offset of the secondary coil W3 relative to the primary coil W1 or W2 becomes larger, thereby reducing the current and loss when the primary coils W1 or W2 are used as the main transmitting coils. The primary coils W1, the auxiliary coils Wa1, the primary coils W2, and the auxiliary coils Wa2 are respectively coupled with the secondary coils W3 in the magnetic field, M 13 、M a1 、M 23 and M a2 The values ​​are all mutual inductance. The primary coil W1 and the auxiliary coil Wa1 are decoupled from each other, the primary coil W2 and the auxiliary coil Wa2 are decoupled from each other, and the primary coil W1 and the primary coil W2 are decoupled from each other. Since the auxiliary coil Wa1 and the auxiliary coil Wa2 are far apart and have a small area, the coupling between the two is also ignored in the analysis.

[0057] Take the primary coil W1 and the auxiliary coil Wa1 as an example:

[0058] The impedance reflected from the secondary coil W3 to the primary coil W1 is:

[0059]

[0060] The impedance reflected from the secondary coil W3 to the auxiliary coil Wa1 is:

[0061]

[0062] The total impedance seen from the primary input is:

[0063]

[0064] When the secondary coil W3 moves from one end of the primary coil W1 to one end of the primary coil W2, M 13 Approaching zero, Z Ra1 The amplitude of Z approaches infinitesimal. inThe first term of approaches infinity, while the second term approaches zero. When the primary coil W1 is used as the main transmitting coil, the current thereon also approaches zero, thereby realizing the automatic switching of the main transmitting coil, thereby improving the power transmission efficiency in a large offset range.

[0065] When the secondary coil W3 moves from one end of the primary coil W2 back to one end of the primary coil W1, the current on the primary coil W2 approaches zero according to the same principle as above, and automatic switching is achieved, thereby finally realizing the automatic switching function between two adjacent primary coil groups.

[0066] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A compensation circuit structure for a wireless charging coil with large offset, comprising: a power input terminal; A primary circuit having a primary coil; a secondary circuit having a secondary coil; It is characterized in that the primary circuit includes at least two groups of primary coil groups, and each group of the primary coil groups includes: The primary coil is connected in series with the compensation element to form a resonant circuit; an auxiliary coil connected in parallel with the auxiliary compensation element to form an auxiliary resonant circuit; The resonant circuit is connected in series with the auxiliary resonant circuit and then connected to the power input terminal. Both the primary coil and the auxiliary coil are magnetically coupled with the secondary coil.

2. The compensation circuit structure for a wireless charging coil with large offset as claimed in claim 1, characterized in that: The compensation element is a compensation capacitor, and the auxiliary compensation element is an auxiliary compensation capacitor.

3. The compensation circuit structure for a wireless charging coil with large offset as claimed in claim 2, characterized in that: The auxiliary coil resonates with the auxiliary compensation element at the switching frequency, that is: Where ω is the operating angular frequency, ω=2πf, f is the operating frequency, L a1 is the self-inductance of the auxiliary coil, C a1 is the capacitance value of the auxiliary compensation element.

4. The compensation circuit structure for a wireless charging coil with large offset as claimed in claim 1, characterized in that: The primary coil resonates with the compensation element and the auxiliary compensation element at the switching frequency, that is: Wherein, ω is the operating angular frequency, ω=2πf, f is the operating frequency, L1 is the self-inductance of the primary coil, C1 is the capacitance value of the compensation element, C a1 is the capacitance value of the auxiliary compensation element.

5. The compensation circuit structure for a wireless charging coil with large offset according to any one of claims 1 to 4, characterized in that: There is magnetic field coupling between the primary coils and the auxiliary coils in two adjacent primary coil groups.

6. The compensation circuit structure for a wireless charging coil with large offset as claimed in claim 5, characterized in that: When two adjacent groups of primary coils are on the same layer structure, the auxiliary coils are all located inside the corresponding primary coils, and the primary coils in the two adjacent groups have a preset distance; When two adjacent groups of primary coils are located on different layer structures, the auxiliary coils are located above or below the corresponding primary coils, and one group of primary coils is located above or below the other group of primary coils; When the same group of primary coil groups are on the same layer structure and two adjacent groups of primary coil groups are on different layer structures, the auxiliary coils are all located inside the corresponding primary coils, and one group of primary coils is located above or below the other group of primary coils; When the primary coil groups of the same group are on different layer structures and two adjacent primary coil groups are on the same layer structure, the auxiliary coils are located above or below the corresponding primary coils, and the primary coils in the two adjacent groups have a preset distance.

7. The compensation circuit structure for a wireless charging coil with large offset according to any one of claims 1 to 4, characterized in that: There is decoupling between the primary coils and the auxiliary coils in two adjacent groups of primary coils.

8. The compensation circuit structure for a wireless charging coil with large offset as claimed in claim 7, characterized in that: The primary coil and the auxiliary coil in the same group are decoupled by partially overlapping the coils.

9. The compensation circuit structure for a wireless charging coil with large offset as claimed in claim 7, characterized in that: The primary coils in two adjacent groups are decoupled by partially overlapping the coils.

10. The compensation circuit structure for a wireless charging coil with large offset according to claim 7, characterized in that: The auxiliary coils in two adjacent groups have a preset distance.

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