Multiphase magnetic coupling structure, series compensation circuit and wireless charging system

Abstract

The invention relates to a multi-phase magnetic coupling structure, a series compensation circuit and a wireless charging system, and relates to the technical field of wireless power transmission, the multi-phase magnetic coupling structure comprises a primary side magnetic energy emission structure and a secondary side magnetic energy receiving structure, the primary side magnetic energy emission structure comprises a first magnetic core and an emission coil; the secondary side magnetic energy receiving structure comprises a second magnetic core and a receiving coil; the transmitting coil and the receiving coil are both multi-phase bipolar coils; therefore, the magnetic coupling structure provided by the invention is higher in magnetic field intensity, higher in power density and obviously improved in transmission efficiency, the transmission efficiency of the structure can reach more than 94% after the front end voltage is increased to 50V, and the highest efficiency is close to 96%.

Description

Technical Field

[0001] The present disclosure relates to the technical field of wireless power transmission, and in particular to a multi-phase magnetic coupling structure, a series compensation circuit and a wireless charging system. Background Art

[0002] The wireless power transmission system realizes the transmission of electric energy through air based on the electromagnetic induction effect. The magnetic coupling coil is the core component for realizing electromagnetic induction and transmitting energy. Its structural design has an important influence on key performance parameters of the system, such as efficiency, power, power density, offset tolerance and electromagnetic leakage level.

[0003] For high-power device wireless charging systems, the volume and mass of the magnetic coupling structure are directly related to the power density of the overall system output. Therefore, while increasing the power level, it is also necessary to meet the same vehicle integration requirements as low-power systems, such as the actual size of the coil structure, floor space, and overall mass requirements, making it more difficult to increase output power and achieve high power density under certain restrictions.

[0004] At present, the mainstream magnetic coupling coil structure is mainly divided into two categories: single coil structure and double-D (DD) coil structure. The single coil structure is mainly circular and rectangular coils. This type of coil is a unipolar coil with a simple structure, low manufacturing cost, and easy installation and portability, but the power density is low and the horizontal dynamic anti-deviability is insufficient.

[0005] The double D-type structure is a double-window coil wound by a coil. This structure is a single-phase bipolar coil structure, that is, the magnetic field forms a loop in the unified coil as a whole. Taking the primary coil as an example, the magnetic lines of force flow out from the left window and flow into the right window through the secondary structure (only a brief description is given here. In the actual wireless charging system, the direction of the magnetic field changes rapidly, and the magnetic fields on both sides change alternately at the same time), forming a complete magnetic flux loop. This coil structure has high transmission efficiency and strong lateral anti-deviability. Because the coil presents a double-window structure, the effective transmission distance is twice that of the single coil structure. However, the power density of this structure is small, the magnetic induction intensity is unevenly distributed on the coil, and the loss at the center of the coil is large and the temperature rise is high. When the system power is above 10kW, the temperature rise of the wire cannot be ignored. The DDQ and BBP coils derived from the DD-type coil structure also further improve the power density and anti-deviability on this structure, but there is still a problem of electromagnetic coupling zero point, which affects the stability of the system and restricts the improvement of power density. The above two types of coil structures are both single-phase coil structures in a topological sense, and have the disadvantages of energy coupling zero point and low coil utilization.

[0006] Therefore, those skilled in the art urgently need to provide a new magnetic coupling coil structure to meet the increasing demand for high power density energy transmission and omnidirectional anti-deviation capability of wireless charging technology. Summary of the invention

[0007] In order to solve the above technical problems, the present disclosure provides a multi-phase magnetic coupling structure, a series compensation circuit and a wireless charging system to match the increasing high power density energy transmission and omnidirectional anti-deviation capability requirements of wireless charging technology.

[0008] In a first aspect, the present disclosure provides a multi-phase magnetic coupling structure, comprising a primary magnetic energy transmitting structure and a secondary magnetic energy receiving structure that are relatively arranged, wherein the primary magnetic energy transmitting structure comprises a first magnetic core and a transmitting coil, and the transmitting coil is located on a side surface of the first magnetic core facing the secondary magnetic energy receiving structure; the secondary magnetic energy receiving structure comprises a second magnetic core and a receiving coil, and the receiving coil is located on a side surface of the second magnetic core facing the primary magnetic energy transmitting structure; the transmitting coil faces the receiving coil; the transmitting coil and the receiving coil are both multi-phase bipolar coils.

[0009] Optionally, the transmitting coil and the receiving coil both include a first phase coil, a second phase coil, and a third phase coil, the first phase coil, the second phase coil, and the third phase coil both include a first sub-coil and a second sub-coil, the number of the first sub-coil and the second sub-coil in the same phase coil is 1, the first sub-coil and the second sub-coil are sector coils of equal size, and the included angle of the sector coils is 120°;

[0010] The first sub-coil and the second sub-coil are connected in series, the first sub-coil and the second sub-coil are located in different planes, and a projection of the first sub-coil on the first magnetic core is centrally symmetric to a projection of the second sub-coil on the first magnetic core.

[0011] Optionally, the first phase coil, the second phase coil, and the third phase coil are spliced ​​in sequence along the vertices of the sector-shaped coil, and the formed transmitting coil or receiving coil is in a double-layered circular shape.

[0012] Optionally, on a side of the transmitting coil opposite to the receiving coil, a projection of the first phase coil in the transmitting coil overlaps with a projection of the first phase coil in the receiving coil on the plane where the circle is located, a projection of the second phase coil in the transmitting coil overlaps with a projection of the second phase coil in the receiving coil on the plane where the circle is located, and a projection of the third phase coil in the transmitting coil overlaps with a projection of the third phase coil in the receiving coil on the plane where the circle is located.

[0013] Optionally, the first phase, the second phase and the third phase in the three-phase coil are equivalent phases to each other.

[0014] Optionally, along the direction from the transmitting coil to the first magnetic core, the projection of the transmitting coil is located within the projection of the first magnetic core; along the direction from the receiving coil to the second magnetic core, the projection of the receiving coil is located within the projection of the second magnetic core.

[0015] Optionally, the primary magnetic energy emitting structure is coupled to the secondary magnetic energy receiving structure; a distance between the primary magnetic energy emitting structure and the secondary magnetic energy receiving structure is 20cm≤D≤40cm.

[0016] Optionally, the first phase coil, the second phase coil, and the third phase coil in the transmitting coil or the receiving coil are connected, and the turns of the first phase coil, the second phase coil, and the third phase coil are in close contact with each other;

[0017] The transmitting coil is attached to the first magnetic core, and the receiving coil is attached to the second magnetic core.

[0018] In a second aspect, the present disclosure provides a series compensation circuit, comprising the multi-phase magnetic coupling structure as described in the first aspect, wherein the transmission power between the transmitting end and the receiving end in the series compensation circuit is:

[0019]

[0020] Among them, I v ,I g is the phase current vector of the transmitting end and the receiving end, M gv is the coupled mutual inductance block matrix at the receiving end, and ω is the circuit frequency.

[0021] In a third aspect, the present disclosure provides a wireless charging system, comprising a primary circuit and a secondary circuit, and the multi-phase magnetic coupling structure as described in the first aspect, wherein a transmitting coil in the multi-phase magnetic coupling structure is connected to the primary circuit, and a receiving coil in the multi-phase magnetic coupling structure is connected to the secondary circuit;

[0022] The primary circuit includes a three-phase inverter circuit, the first phase coil, the second phase coil, and the third phase coil in the transmitting coil respectively include a head end and a tail end, the head ends of the first phase coil, the second phase coil, and the third phase coil in the transmitting coil are respectively connected in series with the corresponding primary compensation capacitors, and then connected in series with the three bridge arms of the three-phase inverter circuit; the tail ends of the first phase coil, the second phase coil, and the third phase coil in the transmitting coil are twisted together to form a neutral point;

[0023] The secondary circuit includes a rectifier circuit, and the first phase coil, the second phase coil, and the third phase coil in the receiving coil respectively include a head end and a tail end. The head ends of the first phase coil, the second phase coil, and the third phase coil in the receiving coil are respectively connected in series with their corresponding secondary compensation capacitors and then connected to the rectifier circuit. The tail ends of the first phase coil, the second phase coil, and the third phase coil in the receiving coil are twisted together to form a neutral point.

[0024] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0025] Compared with the unipolar coil with simple structure and low power density, the multi-phase bipolar coil in the magnetic coupling structure has higher magnetic field strength, higher power density and significantly improved transmission efficiency. After the front-end voltage rises to 50V, the transmission efficiency of this structure can reach more than 94%, and the maximum efficiency is close to 96%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0028] Figure 1 Shown is a schematic diagram of a multi-phase magnetic coupling structure provided by an embodiment of the present disclosure;

[0029] Figure 2 Shown is a schematic diagram of a transmitting coil and a receiving coil structure provided by an embodiment of the present disclosure;

[0030] Figure 3 A schematic diagram of a series compensation circuit provided by an embodiment of the present disclosure;

[0031] Figure 4 An overall circuit diagram of an experimental platform provided by an embodiment of the present disclosure;

[0032] Figure 5 An overall topology diagram of a wireless charging system provided in an embodiment of the present disclosure;

[0033] Figure 6 A schematic diagram of an inverter circuit and a rectifier circuit in a wireless charging system provided by an embodiment of the present disclosure;

[0034] Figure 7A schematic diagram comparing the leakage magnetic phenomenon of a multi-phase magnetic coupling structure and a single-phase bipolar coil provided in an embodiment of the present disclosure;

[0035] Figure 8 A schematic diagram showing a comparison of the magnetic flux at the air gap between a multi-phase magnetic coupling structure and a single-phase bipolar coil provided in an embodiment of the present disclosure;

[0036] Fig. 9 A schematic diagram of a magnetic field representation of a multi-phase magnetic coupling structure provided in an embodiment of the present disclosure;

[0037] Fig.10 A schematic diagram comparing the output power of a multi-phase coil and a common DD coil in a multi-phase magnetic coupling structure provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0040] Figure 1 Shown is a schematic diagram of a multi-phase magnetic coupling structure provided by an embodiment of the present disclosure; Figure 2 The figure shows a schematic diagram of a transmitting coil and a receiving coil structure provided by an embodiment of the present disclosure; please refer to Figure 1 and Figure 2 The present disclosure provides a multi-phase magnetic coupling structure 00, including a primary magnetic energy transmitting structure 01 and a secondary magnetic energy receiving structure 02 which are arranged relatively to each other, wherein the primary magnetic energy transmitting structure 01 includes a first magnetic core 001 and a transmitting coil 011, wherein the transmitting coil 011 is located on a side surface of the first magnetic core 001 facing the secondary magnetic energy receiving structure 02; the secondary magnetic energy receiving structure 02 includes a second magnetic core 002 and a receiving coil 022, wherein the receiving coil 022 is located on a side surface of the second magnetic core 002 facing the primary magnetic energy transmitting structure 01; the transmitting coil 011 faces the receiving coil 022; the transmitting coil 011 and the receiving coil 022 are both multi-phase bipolar coils.

[0041] Specifically, the multi-phase magnetic coupling structure 00 includes a primary magnetic energy transmitting structure 01, the primary magnetic energy transmitting structure 01 includes a first magnetic core 001 and a transmitting coil 011, and the transmitting coil 011 is located on one side surface of the first magnetic core 001 along a direction perpendicular to the plane where the first magnetic core 001 is located; the multi-phase magnetic coupling structure 00 includes a secondary magnetic energy receiving structure 02, the secondary magnetic energy receiving structure 02 includes a second magnetic core 002 and a receiving coil 022, and the receiving coil 022 is located on one side surface of the second magnetic core 002 along a direction perpendicular to the plane where the second magnetic core 002 is located. Optionally, the first magnetic core 001 and the second magnetic core 002 are equal in shape and size, the plane where the first magnetic core 001 is located is parallel to the plane where the second magnetic core 002 is located, the transmitting coil 011 and the receiving coil 022 are equal in size, and the plane where the transmitting coil 011 is located is parallel to the plane where the receiving coil 022 is located. The planes are parallel, and the transmitting coil 011 in the primary magnetic energy transmitting structure 01 faces the receiving coil 022 in the secondary magnetic energy receiving structure 02, that is, in the direction perpendicular to the plane where the first magnetic core 001 is located, the relative position relationship of the various components in the multi-phase magnetic coupling structure 00 is: the first magnetic core 001, the transmitting coil 011, the receiving coil 022, and the second magnetic core 002 are arranged in sequence along the direction from the first magnetic core 001 to the second magnetic core 002; the transmitting coil 011 is opposite to the receiving coil 022, and the transmitting coil 011 is coupled to the receiving coil 022, and the transmitting coil 011 and the receiving coil 022 are both multi-phase bipolar coils, which are formed by superimposing and winding coils of multiple phases. The special design of the coil structure is conducive to improving the magnetic field strength between the coils, so that the overall power transmission takes into account both high transmission efficiency and high anti-offset characteristics.

[0042] In this way, by setting the transmitting coil 011 and the receiving coil 022 between the first magnetic core 001 and the second magnetic core 002 as multi-phase bipolar coils, compared with single-polarity coils with simple structure and low power density, the magnetic field strength between the multi-phase bipolar coils wound by superimposing multiple phase coils is higher, the overall power transmission efficiency is higher, and the anti-offset characteristics are better.

[0043] Please continue to refer to Figure 1 and Figure 2 In an optional embodiment provided by the present disclosure, the transmitting coil 011 and the receiving coil 022 both include a first phase coil 10, a second phase coil 20, and a third phase coil 30. The first phase coil 10, the second phase coil 20, and the third phase coil 30 both include a first sub-coil 111 and a second sub-coil 222. The number of the first sub-coil 111 and the second sub-coil 222 in the same phase coil is 1. The first sub-coil 111 and the second sub-coil 222 are sector coils of equal size, and the included angle of the sector coils is 120°.

[0044] The first sub-coil 111 and the second sub-coil 222 are connected in series. The first sub-coil 111 and the second sub-coil 222 are located in different planes. The projection of the first sub-coil 111 on the first magnetic core 001 is centrally symmetrical with the projection of the second sub-coil 222 on the first magnetic core 001 .

[0045] Specifically, the transmitting coil 011 and the receiving coil 022 in the multi-phase magnetic coupling structure 00 are both multi-phase bipolar coils, the transmitting coil 011 includes a first phase coil 10, a second phase coil 20, and a third phase coil 30, and the receiving coil 022 includes a first phase coil 10, a second phase coil 20, and a third phase coil 30; Figure 2For example, the transmitting coil 011 includes two layers of coils arranged opposite to each other, namely, the first layer of coils and the second layer of coils. The first layer of coils includes the first phase coil 10, the second phase coil 20, and the third phase coil 30. In the first layer of coils, the first phase coil 10, the second phase coil 20, and the third phase coil 30 of the fan-shaped structure are spliced ​​to form a circular structure. The second layer of coils also includes the first phase coil 10, the second phase coil 20, and the third phase coil 30. In the second layer of coils, the first phase coil 10, the second phase coil 20, and the third phase coil 30 of the fan-shaped structure are spliced ​​to form a circular structure. The first phase coil 10 located in the first layer of coils is the first sub-coil 111, and the first phase coil 10 located in the second layer of coils is the second sub-coil 222; the second phase coil 20 located in the first layer of coils is the first sub-coil 111, and the second phase coil 20 located in the second layer of coils is the second sub-coil 222; the third phase coil 30 located in the first layer of coils is the first sub-coil 111, and the third phase coil 30 located in the second layer of coils is the second sub-coil 222. The receiving coil 022 includes two layers of coils arranged opposite to each other, namely, a first layer of coils and a second layer of coils. The first layer of coils includes a first phase coil 10, a second phase coil 20, and a third phase coil 30. In the first layer of coils, the first phase coil 10, the second phase coil 20, and the third phase coil 30 of the fan-shaped structure are spliced ​​to form a circular structure. The second layer of coils also includes a first phase coil 10, a second phase coil 20, and a third phase coil 30. In the second layer of coils, the first phase coil 10, the second phase coil 20, and the third phase coil 30 of the fan-shaped structure are spliced ​​to form a circular structure. The first phase coil 10 in the first layer of coils is the first sub-coil 111, and the first phase coil 10 in the second layer of coils is the second sub-coil 222; the second phase coil 20 in the first layer of coils is the first sub-coil 111, and the second phase coil 20 in the second layer of coils is the second sub-coil 222; the third phase coil 30 in the first layer of coils is the first sub-coil 111, and the third phase coil 30 in the second layer of coils is the second sub-coil 222; each first sub-coil 111 and each second sub-coil 222 are equal in size and are coils of fan-shaped structure, the fan-shaped coil includes two straight sides and one arc side, and the angle between the two straight sides of the fan-shaped coil is 120° The first sub-coil 111 and the second sub-coil 222 in the first phase coil 10 are wound by the same wire, the first sub-coil 111 and the second sub-coil 222 in the second phase coil 20 are wound by the same wire, and the first sub-coil 111 and the second sub-coil 222 in the third phase coil 30 are wound by the same wire; in this way, by arranging the transmitting coil 011 and the receiving coil 022 to be wound by overlapping three coils of different phases, and each phase coil is wound by the same wire into two series-connected sector coils, the magnetic field strength between the multi-phase bipolar coils of this specific structure can be higher and the power density can be higher.

[0046] Please continue to refer to Figure 1 and Figure 2 In an optional embodiment provided in the present disclosure, the first phase coil 10, the second phase coil 20, and the third phase coil 30 are spliced ​​in sequence along the vertices of the sector coil, and the formed transmitting coil 011 or receiving coil 022 is a double-layered circle.

[0047] Specifically, in an optional embodiment provided by the present disclosure, please refer to Figure 2 The transmitting coil 011 includes a first phase coil 10, a second phase coil 20, and a third phase coil 30. The first phase coil 10 is wound by a wire into two sector coils in series, and the angle between the two straight sides of the sector coil is 120°. The second phase coil 20 is wound by a wire into two sector coils in series, and the angle between the two straight sides of the sector coil is 120°. The third phase coil 30 is wound by a wire into two sector coils in series, and the angle between the two straight sides of the sector coil is 120°. The transmitting coil 011 is composed of the first phase coil 10, the second phase coil 20, and the third phase coil 30 are stacked, that is, the transmitting coil 011 is formed by splicing six sector coils of equal size. The transmitting coil 011 is a double-layer stacked circular coil, wherein one layer of circular coils is formed by splicing three first sub-coils 111 of different phases in sequence along the vertices of the sector coils, and the other layer of circular coils is formed by splicing three second sub-coils 222 of different phases in sequence along the vertices of the sector coils; the receiving coil 022 includes a first phase coil 10, a second phase coil 20, and a third phase coil 3 0, the first phase coil 10 is wound into two sector coils in series by a wire, and the angle between the two straight sides of the sector coil is 120°, the second phase coil 20 is wound into two sector coils in series by a wire, and the angle between the two straight sides of the sector coil is 120°, and the third phase coil 30 is wound into two sector coils in series by a wire, and the angle between the two straight sides of the sector coil is 120°; the receiving coil 022 is formed by the first phase coil 10, the second phase coil 20, and the third phase coil 30 superimposed, that is, the receiving coil 022 is composed of six large and small The receiving coil 022 formed by splicing equal sector coils is a double-layer stacked circular coil, wherein one layer of the circular coil is formed by three first sub-coils 111 of different phases spliced ​​in sequence along the vertices of the sector coil, and the other layer of the circular coil is formed by three second sub-coils 222 of different phases spliced ​​in sequence along the vertices of the sector coil; in this way, by stacking and winding three coils of different phases into a double-layer circular structure of the transmitting coil 011 or the receiving coil 022, the magnetic field strength between the multi-phase bipolar coils of this specific structure is higher and the power density is higher.

[0048] In an optional embodiment provided by the present disclosure, on a side opposite to the transmitting coil 011 and the receiving coil 022, the projections of the first phase coil 10 in the transmitting coil 011 and the first phase coil 10 in the receiving coil 022 on the plane where the circle is located overlap, the projections of the second phase coil 20 in the transmitting coil 011 and the second phase coil 20 in the receiving coil 022 on the plane where the circle is located overlap, and the projections of the third phase coil 30 in the transmitting coil 011 and the third phase coil 30 in the receiving coil 022 on the plane where the circle is located overlap.

[0049] For more information, see Figure 1 and Figure 2 The transmitting coil 011 in the multi-phase magnetic coupling structure 00 is opposite to the receiving coil 022. The transmitting coil 011 is formed by superimposing and winding the first phase coil 10, the second phase coil 20, and the third phase coil 30. The receiving coil 022 is formed by superimposing and winding the first phase coil 10, the second phase coil 20, and the third phase coil 30. Each first phase coil 10 includes a first sub-coil 111 and a second sub-coil 222, each second phase coil 20 includes a first sub-coil 111 and a second sub-coil 222, and each third phase coil 3 0 both include a first sub-coil 111 and a second sub-coil 222. Further, a projection of the first phase coil 10 in the transmitting coil 011 on the horizontal plane overlaps with a projection of the first phase coil 10 in the receiving coil 022 on the horizontal plane, a projection of the second phase coil 20 in the transmitting coil 011 on the horizontal plane overlaps with a projection of the second phase coil 20 in the receiving coil 022 on the horizontal plane, and a projection of the third phase coil 30 in the transmitting coil 011 on the horizontal plane overlaps with a projection of the third phase coil 30 in the receiving coil 022 on the horizontal plane.

[0050] In an optional embodiment provided by the present disclosure, please refer to Figure 2 ,exist Figure 2When the coil is placed at the viewing angle shown, the coil is parallel to the horizontal plane, the transmitting coil 011 includes a first circular coil 100 and a second circular coil 200, the first circular coil 100 is located on the side of the second circular coil 200 away from the first magnetic core 001, the first circular coil 100 includes a first sub-coil 11 of the first phase coil 10, a first sub-coil 21 of the second phase coil 20, and a first sub-coil 31 of the third phase coil 30, the second circular coil 200 includes a second sub-coil 12 of the first phase coil 10, a second sub-coil 22 of the second phase coil 20, and a second sub-coil 32 of the third phase coil 30; The receiving coil 022 includes a first circular coil 300 and a second circular coil 400. The first circular coil 300 is located on the side of the second circular coil 400 away from the second magnetic core 002. The first circular coil 300 includes a first sub-coil 41 of the first phase coil 10, a first sub-coil 51 of the second phase coil 20, and a first sub-coil 61 of the third phase coil 30. The second circular coil 400 includes a second sub-coil 42 of the first phase coil 10, a second sub-coil 52 of the second phase coil 20, and a second sub-coil 62 of the third phase coil 30. The first circular coil 100 in the transmitting coil 011 is connected to the receiving coil 011. The projections of the first circular coil 300 in the transmitting coil 011 on the horizontal plane overlap, and in the direction perpendicular to the plane where the first magnetic core 001 is located, the first circular coil 100 in the transmitting coil 011 and the corresponding sub-coils in the first circular coil 300 in the receiving coil 022 are in the same phase. For example, the first sub-coil 11 of the first phase coil 10 in the transmitting coil 011 is in the same phase as the first sub-coil 41 of the first phase coil 10 in the receiving coil 022, and the first sub-coil 21 of the second phase coil 20 in the transmitting coil 011 is in the same phase as the first sub-coil 51 of the second phase coil 20 in the receiving coil 022. Similarly, it should be noted that, based on the overlapping projections of the first circular coil 100 in the transmitting coil 011 and the first circular coil 300 in the receiving coil 022 on the horizontal plane, the first sub-coil 21 of the second phase coil 20 in the transmitting coil 011 and the first sub-coil 51 of the second phase coil 20 in the receiving coil 022 are located in the inner coil (the two middle coils), and the second sub-coil 22 of the second phase coil 20 in the transmitting coil 011 and the second sub-coil 52 of the second phase coil 20 in the receiving coil 022 are located in the outer coil (the two outer coils), and the other two groups are similarly configured.

[0051] Please continue to refer to Figure 2, the first sub-coil 31 of the third phase coil 30 in the transmitting coil 011 is in phase with the first sub-coil 61 of the third phase coil 30 in the receiving coil 022; in the direction perpendicular to the plane where the first magnetic core 001 is located, the second circular coil 200 in the transmitting coil 011 and the corresponding sub-coils in the second circular coil 400 in the receiving coil 022 are in phase, for example, the second sub-coil 12 of the first phase coil 10 in the transmitting coil 011 is in phase with the second sub-coil 42 of the first phase coil 10 in the receiving coil 022, the second sub-coil 22 of the second phase coil 20 in the transmitting coil 011 is in phase with the second sub-coil 52 of the second phase coil 20 in the receiving coil 022, and the second sub-coil 32 of the third phase coil 30 in the transmitting coil 011 is in phase with the second sub-coil 52 of the second phase coil 20 in the receiving coil 022. The second sub-coil 62 of the third phase coil 30 in the coil 022 has the same phase; wherein, the projections of the first sub-coil 111 of each phase in the transmitting coil 011 and the second sub-coil 222 of each phase on the horizontal plane do not overlap, and the projections of the first sub-coil 111 of each phase in the receiving coil 022 and the second sub-coil 222 of each phase on the horizontal plane do not overlap. In this way, in the direction perpendicular to the plane where the first magnetic core 001 is located, by arranging sub-coils with the same phase at corresponding positions in the transmitting coil 011 and the receiving coil 022, the same frequency magnetic field resonance can be generated between the primary magnetic energy transmitting structure 01 and the secondary magnetic energy receiving structure 02, and the energy is coupled from the primary magnetic energy transmitting structure 01 to the secondary magnetic energy receiving structure 02 in the form of a magnetic field, thereby realizing the spatial transfer of energy.

[0052] Please continue to refer to Figure 1 and Figure 2 In an optional embodiment provided in the present disclosure, the first phase, the second phase, and the third phase in the three-phase coil are equivalent phases to each other.

[0053] Specifically, the transmitting coil 011 and the receiving coil 022 both include a first phase coil 10, a second phase coil 20, and a third phase coil 30, wherein the first phase, the second phase, and the third phase are equivalent to each other and can be replaced with each other. For example, in an optional embodiment provided by the present disclosure, the first circular coil 100 in the transmitting coil 011 includes a first sub-coil 11 of the first phase coil 10, a first sub-coil 21 of the second phase coil 20, and a first sub-coil 31 of the third phase coil 30 which are spliced ​​counterclockwise in sequence. In another optional embodiment provided by the present disclosure, the first circular coil 100 in the transmitting coil 011 includes The first sub-coil 21 of the second phase coil 20, the first sub-coil 11 of the first phase coil 10, the first sub-coil 31 of the third phase coil 30, etc., which are spliced ​​counterclockwise, are not listed here one by one. It is only necessary that the transmitting coil 011 and the receiving coil 022 are both composed of coils of three different phases spliced ​​in sequence. In this way, by setting the first phase coil 10, the second phase coil 20, and the third phase coil 30 in the transmitting coil 011 and the receiving coil 022 as interchangeable equivalent phases, more coil design schemes can be provided for the multi-phase magnetic coupling structure 00, enriching the diversity of coil design.

[0054] Please continue to refer to Figure 1 In an optional embodiment provided by the present disclosure, along the direction in which the transmitting coil 011 points to the first magnetic core 001, the projection of the transmitting coil 011 is located within the projection of the first magnetic core 001, and along the direction in which the receiving coil 022 points to the second magnetic core 002, the projection of the receiving coil 022 is located within the projection of the second magnetic core 002.

[0055] Specifically, along a direction perpendicular to the plane where the first magnetic core 001 is located, the multi-phase magnetic coupling structure 00 includes the first magnetic core 001, the transmitting coil 011, the receiving coil 022, and the second magnetic core 002 in sequence, wherein the projection of the first magnetic core 001 on the horizontal plane can completely cover the projection of the transmitting coil 011 on the horizontal plane, and the projection of the second magnetic core 002 on the horizontal plane can completely cover the projection of the receiving coil 022 on the horizontal plane. In this way, by providing a magnetic core that can cover the coil structure, the magnetic field can be enhanced and concentrated, which is beneficial to improving the magnetic field strength of the multi-phase magnetic coupling structure 00.

[0056] Please combine Figure 1 and Figure 2 In an optional embodiment provided in the present disclosure, the primary magnetic energy emitting structure 01 is coupled to the secondary magnetic energy receiving structure 02; the distance between the primary magnetic energy emitting structure 01 and the secondary magnetic energy receiving structure 02 is 20cm≤D≤40cm.

[0057] Specifically, along a direction perpendicular to the plane where the first magnetic core 001 is located, the multi-phase magnetic coupling structure 00 sequentially includes a first magnetic core 001, a transmitting coil 011, a receiving coil 022, and a second magnetic core 002, wherein the transmitting coil 011 is tightly fitted with the first magnetic core 001, the receiving coil 022 is tightly fitted with the second magnetic core 002, the transmitting coil 011 is opposite to the receiving coil 022, the transmitting coil 011 is coupled to the receiving coil 022, and the distance between the transmitting coil 011 and the receiving coil 022 is greater than or equal to 20 cm and less than or equal to 40 cm. Optionally, the distance between the transmitting coil 011 and the receiving coil 022 can be 22 cm, 24 cm, 26 cm, 28 cm, 30 cm, 32 cm, 34 cm, 36 cm, 38 cm... and so on, which are not listed here one by one, but only need to be satisfied. The distance between the primary magnetic energy transmitting structure 01 and the secondary magnetic energy receiving structure 02 is within the range of 20cm≤D≤40cm. When the distance between the primary magnetic energy transmitting structure 01 and the secondary magnetic energy receiving structure 02 is less than 20cm, the distance between the two is too close, the system is in an over-coupling state, and the transmission power decreases as the distance between the transmitting coil 011 and the receiving coil 022 decreases. When the distance between the primary magnetic energy transmitting structure 01 and the secondary magnetic energy receiving structure 02 is greater than 40cm, the distance between the two is too far, the system is in an under-coupling state, and the transmission efficiency decreases as the distance between the transmitting coil 011 and the receiving coil 022 decreases. In this way, setting the distance between the primary magnetic energy transmitting structure 01 and the secondary magnetic energy receiving structure 02 within the range of 20cm≤D≤40cm can maximize the transmission power and transmission efficiency of the system power.

[0058] Please combine Figure 1 and Figure 2 In an optional embodiment provided by the present disclosure, the first phase coil 10, the second phase coil 20, and the third phase coil 30 in the transmitting coil 011 or the receiving coil 022 are connected, and the turns of the first phase coil 10, the second phase coil 20, and the third phase coil 30 are respectively fitted together; the transmitting coil 011 is fitted with the first magnetic core 001, and the receiving coil 022 is fitted with the second magnetic core 002.

[0059] Specifically, the transmitting coil 011 includes a first phase coil 10, a second phase coil 20, and a third phase coil 30. The first phase coil 10 is wound by a wire into a first fan-shaped sub-coil 11 and a second fan-shaped sub-coil 12. The second phase coil 20 is wound by a wire into a first fan-shaped sub-coil 21 and a second fan-shaped sub-coil 22. The third phase coil 30 is wound by a wire into a first fan-shaped sub-coil 31 and a second fan-shaped sub-coil 32. The first phase coil 10, the second phase coil 20, and the third phase coil 30 are tightly fitted, and the turns of each phase coil are tightly fitted; the receiving coil 022 includes a first phase coil 10, a second phase coil 20, and a third phase coil 30. The first phase coil 10 is wound by a wire The first sub-coil 41 and the second sub-coil 42 are wound into a fan-shaped first sub-coil 51 and a fan-shaped second sub-coil 52, the second phase coil 20 is wound into a fan-shaped first sub-coil 51 and a fan-shaped second sub-coil 52 by a single wire, the third phase coil 30 is wound into a fan-shaped first sub-coil 61 and a fan-shaped second sub-coil 62 by a single wire, the first phase coil 10, the second phase coil 20, and the third phase coil 30 are tightly fitted, and the turns of each phase coil are tightly fitted; in addition, the transmitting coil 011 is tightly fitted to the first magnetic core 001, and the receiving coil 022 is tightly fitted to the second magnetic core 002. In this way, by tightly fitting the turns of the coils, the phases of the coils, and the coils to the magnetic cores, the power efficiency of the system can be improved and the power loss can be reduced.

[0060] Figure 3 A schematic diagram of a series compensation circuit provided by an embodiment of the present disclosure is provided in conjunction with Figures 1 to 3 The present disclosure provides a series compensation circuit, including the multi-phase magnetic coupling structure 00 in the above-mentioned embodiment, wherein the transmitting coil and its compensation structure are named as GA (ground assembly) end, and the receiving coil and its compensation structure are named as VA (vehicle assembly) end. The transmission power of the transmitting end GA and the receiving end VA in the series compensation circuit is:

[0061]

[0062] Among them, I v ,I g is the phase current vector of the transmitting end GA and the receiving end VA, M gv is the coupled mutual inductance block matrix at the receiving end, and ω is the circuit frequency.

[0063] Specifically, taking the transmitting end GA as an example, since there are three coils wound, there is a mutual inductance matrix inside the transmitting coil 011, and it is necessary to perform a decoupling analysis on it when calculating the compensation structure parameters, and obtain the required compensation parameters through mutual inductance equivalent calculation.

[0064] Taking the SS (series) resonant compensation network as an example, please refer to Figure 3 , R x is the capacitance value of the electrical device itself, L x is the coil self-inductance, M xx is the coil mutual inductance, C x is the compensation capacitor, I x is the branch current, U x is the branch voltage, jω is the complex frequency domain component. Based on the inductive coupling decoupling formula and Kirchhoff's law (KVL) of the circuit, the loop voltage is calculated as follows:

[0065]

[0066] Since the current flowing into the neutral point is 0, that is, the sum of the three-phase currents of ABC is 0, there is I C =-I A -I B , substitute into formula (1) and A , U B Subtracting, we get:

[0067]

[0068] Considering that the independent capacitance compensation is the induced voltage component, it can be deduced from formula (2):

[0069]

[0070] That is, there is a certain quantitative relationship between the capacitance and the equivalent coil self-inductance, and the compensation capacitance calculation formula is as follows (4):

[0071]

[0072] From the above inference of the capacitance compensation parameters, the overall inductance matrix of the transmitter GA and the receiver VA can be obtained. There are six different coil structures on both the primary and secondary sides, that is, there is a 6×6 large inductance matrix, and the self-inductance matrix is ​​on the diagonal of the overall matrix. The large inductance matrix can be listed as a block matrix model. The relationship of the inductance matrix is ​​as follows:

[0073]

[0074] In formula (5), L gg , L vv are the self-inductance block matrices of the transmitting end GA and the receiving end VA respectively; the current vector is: I L，gv =[I T L,g I T L,v ] T , I L,g ,I L,v Represents the phase current between the transmitting coil 011 and the receiving coil 022.vg 、M gv The mutual inductance block matrix of the transmitting end GA and the receiving end VA is:

[0075]

[0076] The transmitting end GA and the receiving end VA are topologically symmetrical systems and are coupled to each other. Therefore, the six-coil full mutual inductance matrix is ​​a symmetrical matrix, but the block matrix mutual inductance matrix is ​​not symmetrical, that is, there is M T vg ≠M vg , M T gv ≠M gv , under non-ideal conditions, the transmission power between GA and VA is related to their relative rotation position and angle θ, so the full mutual inductance matrix is ​​as follows:

[0077]

[0078] The power transfer expression of the three-phase system can use the coil voltage and current as independent variables. Given the current vector, the complex power transferred from the GA terminal to the VA terminal is:

[0079]

[0080] Among them I v ,I g is the phase current vector of the transmitting end GA and the receiving end VA, and its modulus is the root mean square (RMS) of the high-frequency AC current, V v 、V g It is the induced voltage vector generated by the resonant coupling between GA and VA. Where Vv=jω·M gv I g 、Vg=jω·M T gv I v .

[0081] Assume M gv is a symmetric matrix, the block mutual inductance matrix is ​​also a symmetric matrix, and the phase angle difference between the transmitting end GA and the receiving end VA is π / 2+θ, then the transmission power can be simplified as:

[0082]

[0083] Wherein, ω is the circuit frequency, ω=2π / T, and T is the circuit period.

[0084] Figure 4 An overall circuit diagram of an experimental platform provided in an embodiment of the present disclosure, Figure 5 An overall topology diagram of a wireless charging system provided in an embodiment of the present disclosure, Figure 6This is a schematic diagram of an inverter circuit and a rectifier circuit in a wireless charging system provided by an embodiment of the present disclosure. Figures 1 to 6 The present disclosure provides a wireless charging system, including a primary circuit and a secondary circuit, and the multi-phase magnetic coupling structure 00 in the aforementioned embodiment, the transmitting coil 011 in the multi-phase magnetic coupling structure 00 is connected to the primary circuit, and the receiving coil 022 in the multi-phase magnetic coupling structure 00 is connected to the secondary circuit;

[0085] The primary circuit includes a three-phase inverter circuit. The first phase coil 10, the second phase coil 20, and the third phase coil 30 in the transmitting coil 011 include a head end and a tail end respectively. The head ends of the first phase coil 10, the second phase coil 20, and the third phase coil 30 in the transmitting coil 011 are respectively connected in series with the corresponding primary compensation capacitors, and then connected in series with the three bridge arms of the three-phase inverter circuit respectively; the tail ends of the first phase coil 10, the second phase coil 20, and the third phase coil 30 in the transmitting coil 011 are twisted together to form a neutral point;

[0086] The secondary circuit includes a rectifier circuit. The first phase coil 10, the second phase coil 20, and the third phase coil 30 in the receiving coil 022 include a head end and a tail end respectively. The head ends of the first phase coil 10, the second phase coil 20, and the third phase coil 30 in the receiving coil 022 are respectively connected in series with their corresponding secondary compensation capacitors and then connected to the rectifier circuit. The tail ends of the first phase coil 10, the second phase coil 20, and the third phase coil 30 in the receiving coil 022 are twisted together to form a neutral point.

[0087] Specifically, the overall circuit is modeled and analyzed, an experimental platform is established, and the performance of the multi-phase magnetic coupling structure 00 and the single-phase structure in terms of power density and efficiency at different voltage levels are compared.

[0088] Please refer to Figure 5 , where the transmitting end GA is connected to the high-frequency three-phase inverter structure, the three coil heads are connected in series with their compensation capacitors, and then connected to the three bridge arms of the inverter, and the tail ends of the three coils are twisted together to form a neutral point. Similarly, the receiving end VA is connected to the rectifier circuit.

[0089] A multi-phase magnetic coupling structure 00 provided in the present invention is modeled and analyzed, mainly analyzing its magnetic field performance, and comparing the magnetic induction intensity in the air gap, the trend of magnetic lines of force, the magnetic induction intensity inside the coil, the leakage magnetic phenomenon, etc. of the existing unipolar coil. Figure 7 A schematic diagram comparing the leakage magnetic phenomenon of a multi-phase magnetic coupling structure and a single-phase bipolar coil provided in an embodiment of the present disclosure is provided. Please refer to Figure 7, a sampling point is taken at the center point outside the multi-phase magnetic coupling structure 00 model to explore its magnetic induction intensity. It can be seen that the leakage magnetic field around the air gap of the bipolar coils such as the transmitting coil 011 and the receiving coil 022 is significantly reduced, and the peak value is less than half of the unipolar coil. The reduction of leakage magnetic field helps to improve the electromagnetic energy transmission efficiency of the system and reduce communication equipment failure or data damage caused by electromagnetic interference (EMI).

[0090] In addition, a rectangular space calculation domain is selected in the finite element analysis software to calculate the air gap magnetic flux density. Figure 8 A schematic diagram of the magnetic flux comparison between a multi-phase magnetic coupling structure and a single-phase bipolar coil air gap provided in the embodiment of the present disclosure is provided. Please refer to Figure 8 In the rainbow cloud diagram, the warmer the color, the higher the intensity, and the colder the color, the lower the intensity. It can be seen that the magnetic field distribution of the bipolar coil in the embodiment of the present disclosure is more uniform, and the magnetic field intensity is greater at the coil receiving point, with a red area in the center.

[0091] Fig. 9 A schematic diagram of a magnetic field performance of a multi-phase magnetic coupling structure provided in an embodiment of the present disclosure, Fig. 9 The left half is a schematic diagram of the magnetic induction intensity on the surface of the transmitting coil in the embodiment of the present disclosure. Fig. 9 The right half is a diagram showing the distribution trend of the air gap magnetic field lines in the embodiment of the present disclosure. Please refer to Fig. 9 It can be seen that the multi-phase magnetic coupling structure 00 has three energy coupling peak points, and there is also a certain amount of energy transmission at the intersection of the coils, and the electromagnetic coupling zero point almost does not exist. This shows that the multi-phase magnetic coupling structure 00 has better electromagnetic characteristics.

[0092] Fig.10 This is a schematic diagram comparing the output power of a multi-phase coil and a common DD coil in a multi-phase magnetic coupling structure provided in an embodiment of the present disclosure. Please refer to Fig.10 The blue line in the figure represents the power density and efficiency of the multi-phase magnetic coupling structure 00, and the red line in the figure represents the power density and efficiency of the DD structure. From the curve trend, it can be seen that the multi-phase magnetic coupling structure 00 is significantly better than the DD structure in power density, and the transmission efficiency is also significantly improved. After the front-end voltage rises to 50V, the transmission efficiency of the structure can reach more than 94%, and the maximum efficiency is close to 96%.

[0093] In summary, the present disclosure provides a multi-phase magnetic coupling structure, a series compensation circuit and a wireless charging system. By setting the transmitting coil and the receiving coil between the first magnetic core and the second magnetic core to be multi-phase bipolar coils, compared with the unipolar coils with simple structure and low power density, the transmitting coil and the receiving coil are formed by superimposing and winding three coils of different phases, and each phase coil is wound into two series-connected fan-shaped coils using a wire, so that the magnetic field intensity between the multi-phase bipolar coils of this specific structure is higher and the power density is higher. In the direction perpendicular to the plane where the first magnetic core is located, by setting sub-coils with the same phase at corresponding positions in the transmitting coil and the receiving coil, the same frequency magnetic field resonance can be generated between the primary magnetic energy transmitting structure and the secondary magnetic energy receiving structure, and the energy is coupled from the primary magnetic energy transmitting structure to the secondary magnetic energy receiving structure in the form of a magnetic field, thereby realizing the spatial transfer of energy. By setting the first phase coil, the second phase coil, and the third phase coil in the transmitting coil and the receiving coil to equivalent phases that can be replaced with each other, more coil design schemes can be provided for the multi-phase magnetic coupling structure, enriching the diversity of coil design. By setting a magnetic core that can cover the coil structure, the magnetic field can be enhanced and concentrated, which is beneficial to improving the magnetic field strength of the multi-phase magnetic coupling structure. Setting the distance between the primary magnetic energy transmitting structure and the secondary magnetic energy receiving structure within the range of 20cm≤D≤40cm can maximize the transmission power and transmission efficiency of the system power. By closely fitting the coil turns, the coil phases, and the coil to the magnetic core, the power efficiency of the system can be improved and the power loss can be reduced. This structure is significantly better than the double D-type structure in power density, and the transmission efficiency is also significantly improved. After the front-end voltage rises to 50V, the transmission efficiency of the structure can reach more than 94%, and the maximum efficiency is close to 96%.

[0094] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multiphase magnetic coupling structure, characterized in that: It comprises a primary magnetic energy transmitting structure and a secondary magnetic energy receiving structure which are arranged opposite to each other, wherein the primary magnetic energy transmitting structure comprises a first magnetic core and a transmitting coil, and the transmitting coil is located on a side surface of the first magnetic core facing the secondary magnetic energy receiving structure; The secondary magnetic energy receiving structure includes a second magnetic core and a receiving coil, wherein the receiving coil is located on a side surface of the second magnetic core facing the primary magnetic energy transmitting structure; the transmitting coil and the receiving coil are both multi-phase bipolar coils.

2. The multiphase magnetic coupling structure according to claim 1, characterized in that: The transmitting coil and the receiving coil each include a first phase coil, a second phase coil, and a third phase coil, the first phase coil, the second phase coil, and the third phase coil each include a first sub-coil and a second sub-coil, the number of the first sub-coil and the second sub-coil in the same phase coil is 1, the first sub-coil and the second sub-coil are sector coils of equal size, and the included angle of the sector coils is 120°; The first sub-coil and the second sub-coil are connected in series, the first sub-coil and the second sub-coil are located in different planes, and a projection of the first sub-coil on the first magnetic core is centrally symmetric to a projection of the second sub-coil on the first magnetic core.

3. The multi-phase magnetic coupling structure according to claim 2, characterized in that: The first phase coil, the second phase coil and the third phase coil are sequentially spliced ​​along the vertices of the sector-shaped coil, and the formed transmitting coil or receiving coil is in the shape of a double-layered circle.

4. The multi-phase magnetic coupling structure according to claim 3, characterized in that: On a side of the transmitting coil opposite to the receiving coil, a projection of a first phase coil in the transmitting coil overlaps with a projection of a first phase coil in the receiving coil on the plane where the circle is located, a projection of a second phase coil in the transmitting coil overlaps with a projection of a second phase coil in the receiving coil on the plane where the circle is located, and a projection of a third phase coil in the transmitting coil overlaps with a projection of a third phase coil in the receiving coil on the plane where the circle is located.

5. The multi-phase magnetic coupling structure according to claim 3, characterized in that: The first phase, the second phase and the third phase of the three-phase coil are equivalent phases to each other.

6. The multi-phase magnetic coupling structure according to claim 1, characterized in that: Along the direction from the transmitting coil to the first magnetic core, the projection of the transmitting coil is located within the projection of the first magnetic core; along the direction from the receiving coil to the second magnetic core, the projection of the receiving coil is located within the projection of the second magnetic core.

7. The multi-phase magnetic coupling structure according to claim 1, characterized in that: The primary magnetic energy emitting structure is coupled to the secondary magnetic energy receiving structure; the distance between the primary magnetic energy emitting structure and the secondary magnetic energy receiving structure is 20cm≤D≤40cm.

8. The multi-phase magnetic coupling structure according to claim 3, characterized in that: The first phase coil, the second phase coil, and the third phase coil in the transmitting coil or the receiving coil are connected, and the turns of the first phase coil, the second phase coil, and the third phase coil are in close contact with each other; The transmitting coil is attached to the first magnetic core, and the receiving coil is attached to the second magnetic core.

9. A series compensation circuit, characterized in that: The multiphase magnetic coupling structure according to any one of claims 1 to 8 is included, and the transmission power between the transmitting end and the receiving end in the series compensation circuit is: Among them, I v ,I g is the phase current vector of the transmitting end and the receiving end, M gv is the receiving end coupling mutual inductance block matrix, and ω is the circuit frequency.

10. A wireless charging system, characterized in that: It comprises a primary circuit and a secondary circuit, and a multiphase magnetic coupling structure according to any one of claims 1 to 8, wherein a transmitting coil in the multiphase magnetic coupling structure is connected to the primary circuit, and a receiving coil in the multiphase magnetic coupling structure is connected to the secondary circuit; The primary circuit includes a three-phase inverter circuit, the first phase coil, the second phase coil, and the third phase coil in the transmitting coil respectively include a head end and a tail end, the head ends of the first phase coil, the second phase coil, and the third phase coil in the transmitting coil are respectively connected in series with the corresponding primary compensation capacitors, and then connected in series with the three bridge arms of the three-phase inverter circuit; the tail ends of the first phase coil, the second phase coil, and the third phase coil in the transmitting coil are twisted together to form a neutral point; The secondary circuit includes a rectifier circuit, and the first phase coil, the second phase coil, and the third phase coil in the receiving coil respectively include a head end and a tail end. The head ends of the first phase coil, the second phase coil, and the third phase coil in the receiving coil are respectively connected in series with their corresponding secondary compensation capacitors and then connected to the rectifier circuit. The tail ends of the first phase coil, the second phase coil, and the third phase coil in the receiving coil are twisted together to form a neutral point.

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