Magnetic coupling mechanism suitable for coaxial rotation wireless power transmission

Abstract

The invention provides a magnetic coupling mechanism suitable for coaxial rotation wireless power transmission. The magnetic coupling mechanism is used for solving the problem of poor power transmission stability in an existing rotary wireless charging system. Comprising a primary side assembly and a secondary side assembly which are coaxially arranged in a sleeved mode, the primary side assembly comprises a primary side annular magnetic core, a primary side D-axis coil and a primary side Q-axis coil, the primary side D-axis coil and the primary side Q-axis coil are wound on the outer side arc face of the primary side annular magnetic core in a stacked mode, and the phase difference of excitation currents of the primary side D-axis coil and the primary side Q-axis coil is 90 degrees. According to the invention, the magnetic fields generated by the primary side D-axis coil and the primary side Q-axis coil are more uniform and stable after vector synthesis, the influence of offset caused by the metal shell and coaxial rotation is small, and the device is suitable for a rotary wireless power transmission device needing to be protected by the metal shell.

Description

Technical Field

[0001] The present invention relates to the field of wireless power transmission, in particular to a magnetic coupling mechanism suitable for coaxial rotation wireless power transmission. Background Art

[0002] With the continuous development of electronic information technology and industrial automation control, wireless power transmission technology is becoming increasingly mature and widely used in industrial and military fields. Currently, wireless power transmission technology is mainly used in the wireless charging of electric vehicles and consumer electronics. However, it is less widely used in fields requiring rotary power supply, such as oil drilling, radar power supply, and helicopter main wing de-icing, and its development is still immature.

[0003] In rotating equipment, metal casing is often required for protection. If the coupling mechanism adopts the winding method of axial magnetic field, the magnetic field will leak on the metal casing, resulting in additional loss and a huge impact on parameters such as coil self-inductance and mutual inductance. If the coupling mechanism adopts the bipolar DD coil winding method that generates horizontal magnetic field, problems such as coupling coefficient crossing zero point will occur, which is not conducive to stable power transmission during rotation. Summary of the Invention

[0004] The purpose of the present invention is to provide a magnetic coupling mechanism suitable for coaxial rotational wireless power transmission, so as to solve the technical problem of poor power transmission stability in existing rotational wireless charging systems.

[0005] A magnetic coupling mechanism suitable for coaxial rotating wireless power transmission, comprising a primary assembly and a secondary assembly coaxially arranged, wherein the primary assembly comprises a primary annular magnetic core, a primary D-axis coil, and a primary Q-axis coil, wherein the phase difference between the excitation currents of the primary D-axis coil and the primary Q-axis coil is 90°;

[0006] The primary D-axis coil and the primary Q-axis coil are stacked and wound on the outer arc surface of the primary annular magnetic core. The primary D-axis coil and the primary Q-axis coil respectively include a plurality of primary D-axis sub-coils and primary Q-axis sub-coils sequentially wound along the outer arc surface of the primary annular magnetic core. The primary D-axis sub-coil and the primary Q-axis sub-coil are both arc-surface rectangular coils. The secondary side component includes a secondary side annular magnetic core, a secondary side D-axis coil and a secondary side Q-axis coil. The secondary side annular magnetic core is coaxially arranged with the primary side annular magnetic core. The secondary side D-axis coil and the secondary side Q-axis coil are stacked and wound on the inner arc surface of the secondary side annular magnetic core. The secondary side D-axis coil and the secondary side Q-axis coil include a number of secondary side D-axis sub-coils and secondary side Q-axis sub-coils wound in sequence along the inner arc surface of the primary side annular magnetic core. The secondary side D-axis sub-coil and the secondary side Q-axis sub-coil are both arc-surface rectangular coils.

[0007] Optionally, the winding wire diameters of the primary D-axis coil, the primary Q-axis coil, the secondary D-axis coil and the secondary Q-axis coil are the same.

[0008] Optionally, the lengths of the arc sides of the primary D-axis sub-coil and the primary Q-axis sub-coil are both C1 / N p ;

[0009] The lengths of the arc sides of the secondary side D axis sub-coil and the secondary side Q axis sub-coil are both C2 / N p , where the number of primary D-axis sub-coil, primary Q-axis sub-coil, secondary D-axis sub-coil and secondary Q-axis sub-coil is N p , C1 is the circumference of the outer arc of the primary ring core, and C2 is the circumference of the inner arc of the secondary ring core.

[0010] Optionally, the number of turns of the i-th primary D-axis sub-coil, primary Q-axis sub-coil, secondary D-axis sub-coil, and secondary Q-axis sub-coil is:

[0011] ;

[0012] Where H m * is the preset magnetic field strength amplitude, N di The value of is the number of turns of the i-th primary D-axis sub-coil and the secondary D-axis sub-coil, N qi The value of is the number of turns of the i-th primary Q-axis sub-coil and the secondary Q-axis sub-coil, N di = 0, the i-th primary D-axis sub-coil and the secondary D-axis sub-coil are both single-wound wires, N qi =0, the i-th primary Q-axis sub-coil and the secondary Q-axis sub-coil are both single-winding wires.

[0013] Optional, N di When it is a positive number, the i-th primary D-axis sub-coil and the secondary D-axis sub-coil are wound clockwise, N di When it is a negative number, the i-th primary D-axis sub-coil and the secondary D-axis sub-coil are wound counterclockwise;

[0014] N qi When it is a positive number, the i-th primary Q-axis sub-coil and the secondary Q-axis sub-coil are wound clockwise, N qi When it is a negative number, the i-th primary Q-axis sub-coil and the secondary Q-axis sub-coil are wound counterclockwise.

[0015] Optionally, the number of the primary D-axis sub-coil, the primary Q-axis sub-coil, the secondary D-axis sub-coil and the secondary Q-axis sub-coil is 8.

[0016] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0017] 1. The primary D-axis coil and the primary Q-axis coil of the present application generate a decoupled magnetic field. Not only will power not be transmitted between the two primary coils, but the magnetic field generated by the two coils is more uniform and stable after vector synthesis, and is less affected by the offset caused by the metal casing and coaxial rotation. It is suitable for rotating wireless power transmission devices that require metal casing protection.

[0018] 2. This application can set the number of sub-coils, the number of sub-coil turns and the winding direction according to the transmission power requirements to meet the transmission requirements under various working conditions.

[0019] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings of the present invention are described below.

[0021] Figure 1 Schematic diagram of the structure of the magnetic coupling mechanism of the present invention.

[0022] Figure 2 Schematic diagram of the magnetic field direction after vector synthesis of each sub-coil group of the present invention.

[0023] Figure 3 Magnetic field intensity vector diagram of the two-pole eight-phase coupling mechanism in the simulation of the present invention.

[0024] Figure 4 This is a curve diagram of the change in the coupling coefficient of the synthetic magnetic field when rotating at different angles in the simulation of the present invention.

[0025] Figure 5 Magnetic field intensity vector diagram of four groups of two-pole eight-phase coupling mechanisms in the simulation of the present invention.

[0026] In the figure: 1-primary annular magnetic core; 2-primary D-axis coil; 21-primary D-axis sub-coil; 3-primary Q-axis coil; 31-primary Q-axis sub-coil; 4-secondary annular magnetic core; 5-secondary D-axis coil; 51-secondary D-axis sub-coil; 6-secondary Q-axis coil; 61-secondary Q-axis sub-coil. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and examples.

[0028] Example:

[0029] like Figure 1A magnetic coupling mechanism suitable for coaxial rotating wireless power transmission is shown, comprising a primary assembly and a secondary assembly coaxially arranged, wherein the primary assembly comprises a primary annular magnetic core 1, a primary D-axis coil 2, and a primary Q-axis coil 3;

[0030] The primary D-axis coil 2 and the primary Q-axis coil 3 are stacked and wound on the outer arc surface of the primary annular magnetic core 1. The primary D-axis coil 2 and the primary Q-axis coil 3 respectively include a number of primary D-axis sub-coils 21 and primary Q-axis sub-coils 31 wound in sequence along the outer arc surface of the primary annular magnetic core 1. The primary D-axis sub-coil 21 and the primary Q-axis sub-coil 31 are both arc-surface rectangular coils.

[0031] The secondary side assembly includes a secondary side annular magnetic core 4, a secondary side D-axis coil 5 and a secondary side Q-axis coil 6. The secondary side annular magnetic core 4 is coaxially arranged with the primary side annular magnetic core 1.

[0032] The secondary D-axis coil 5 and the secondary Q-axis coil 6 are stacked and wound on the inner arc surface of the secondary annular magnetic core 4. The secondary D-axis coil 5 and the secondary Q-axis coil 6 include a number of secondary D-axis sub-coils 51 and secondary Q-axis sub-coils 61 wound in sequence along the inner arc surface of the primary annular magnetic core 1. The secondary D-axis sub-coil 51 and the secondary Q-axis sub-coil 61 are both arc-surface rectangular coils.

[0033] In this embodiment, the phase difference of the excitation current applied to the primary D-axis coil 2 and the primary Q-axis coil 3 is 90°, and the magnetic fields generated by the two coils are perpendicular in vector, so the coils of the two axes are decoupled from each other and there is no power transmission between them. In this embodiment, the number of primary D-axis sub-coils 21, primary Q-axis sub-coils 31, secondary D-axis sub-coils 51 and secondary Q-axis sub-coils 61 is the same. Several primary D-axis sub-coils 21 are wound in sequence by a winding wire, several primary Q-axis sub-coils 31 are wound in sequence by a winding wire, several secondary D-axis sub-coils 51 are wound in sequence by a winding wire, and several secondary Q-axis sub-coils 61 are wound in sequence by a winding wire, and the winding wires have the same diameter.

[0034] As an embodiment of the present application, the lengths of the arc sides of the primary D-axis sub-coil 21 and the primary Q-axis sub-coil 31 are both C1 / N p ;

[0035] The lengths of the arc sides of the secondary D-axis sub-coil 51 and the secondary Q-axis sub-coil 61 are both C2 / N p , where the number of the primary D-axis sub-coil 21, the primary Q-axis sub-coil 31, the secondary D-axis sub-coil 51 and the secondary Q-axis sub-coil 61 is N p , C1 is the circumference of the outer arc of the primary annular core 1 , and C2 is the circumference of the inner arc of the secondary annular core 4 .

[0036] In this embodiment, adjacent sub-coils are closely arranged, and the diameter of the winding wire of the sub-coil is much smaller than the length of the arc side. Therefore, the influence of the winding wire diameter is ignored when calculating the length of the arc side of the sub-coil.

[0037] As an embodiment of the present application, the number of turns of the i-th primary D-axis sub-coil 21, the primary Q-axis sub-coil 31, the secondary D-axis sub-coil 51, and the secondary Q-axis sub-coil 61 is:

[0038]

[0039] Where H m * is the preset magnetic field strength amplitude, N di The value of is the number of turns of the i-th primary D-axis sub-coil 21 and the secondary D-axis sub-coil 51, N qi The value of is the number of turns of the i-th primary Q-axis sub-coil 31 and the secondary Q-axis sub-coil 61, N di = 0, the i-th primary D-axis sub-coil 21 and the secondary D-axis sub-coil 51 are both single winding wires, N qi =0, the i-th primary Q-axis sub-coil 31 and the secondary Q-axis sub-coil 61 are both single winding wires.

[0040] In this embodiment, N di When N is a positive number, the i-th primary D-axis sub-coil 21 and the secondary D-axis sub-coil 51 are wound clockwise. di When it is a negative number, the i-th primary D-axis sub-coil 21 and the secondary D-axis sub-coil 51 are wound counterclockwise;

[0041] N qi When N is a positive number, the i-th primary Q-axis sub-coil 31 and the secondary Q-axis sub-coil 61 are wound clockwise. qi When it is a negative number, the i-th primary Q-axis sub-coil 31 and the secondary Q-axis sub-coil 61 are wound counterclockwise.

[0042] Simulation and verification:

[0043] The number of the primary D-axis sub-coil 21, the primary Q-axis sub-coil 31, the secondary D-axis sub-coil 51 and the secondary Q-axis sub-coil 61 is 8, and the preset magnetic field strength amplitude is , calculate the number of turns and direction parameters of each sub-coil, and round the number of turns, as shown in Table 1.

[0044] Table 1 Number of turns and direction of each sub-coil

[0045] i 1 2 3 4 5 6 7 8 <![CDATA[N di ]]> 4 3 0 -3 -4 -3 0 3 <![CDATA[N qi ]]> 0 3 4 3 0 -3 -4 -3

[0046] The outer ring radius r1 of the primary annular core 1 is set to 235 mm, the inner ring radius r2 of the secondary annular core 4 is set to 288 mm, the height h of the primary annular core 1 and the secondary annular core 4 are both 44 m, the core spacing (air gap) between the primary annular core 1 and the secondary annular core 4 is 53 mm, the winding wire specification is 0.1×180 strands of Litz wire, and the wire diameter is about 2 mm. The calculated results are C1=1475.8 mm and C2=1808.64 mm. According to the above parameters and the number of turns of the sub-coil in Table 1, the primary D-axis sub-coil 21 and the primary Q-axis sub-coil 31 are wound on the primary annular core 1, and the secondary D-axis sub-coil 51 and the secondary Q-axis sub-coil 61 are wound on the secondary annular core 4. The specific process is as follows:

[0047] S1: Wind the primary D-axis sub-coil 21 and the primary Q-axis sub-coil 31 with an arc side length of C1 / 8 and a height of h:

[0048] The first to fourth primary D-axis sub-coils 21 and the primary Q-axis sub-coils 31 are wound in sequence, the first to fourth primary D-axis sub-coils 21 are sequentially attached to the outer wall of the primary annular magnetic core 1, and the first to fourth primary Q-axis sub-coils 31 are respectively attached to the outer walls of the first to fourth primary D-axis sub-coils 21; the fifth to eighth primary Q-axis sub-coils 31 and the primary D-axis sub-coils 21 are wound in sequence, the fifth to eighth primary Q-axis sub-coils 31 are sequentially attached to the outer wall of the primary annular magnetic core 1, and the fifth to eighth primary D-axis sub-coils 21 are respectively attached to the outer walls of the fifth to eighth primary Q-axis sub-coils 31.

[0049] S2: Wind the secondary D-axis sub-coil 51 and the secondary Q-axis sub-coil 61 with an arc side length of C2 / 8 and a height of h:

[0050] The first to fourth secondary D-axis sub-coils 51 and the secondary Q-axis sub-coils 61 are wound in sequence, and the first to fourth secondary Q-axis sub-coils 61 are successively attached to the outer wall of the secondary annular magnetic core 4, and the first to fourth secondary D-axis sub-coils 51 are respectively attached to the outer walls of the first to fourth secondary Q-axis sub-coils 61; the fifth to eighth secondary D-axis sub-coils 51 and the secondary Q-axis sub-coils 61 are wound in sequence, and the fifth to eighth secondary D-axis sub-coils 51 are successively attached to the outer wall of the secondary annular magnetic core 4, and the fifth to eighth secondary Q-axis sub-coils 61 are respectively attached to the outer walls of the fifth to eighth secondary D-axis sub-coils 51.

[0051] In this embodiment, after the 8 groups of sub-coils of the primary D-axis coil 2 and the primary Q-axis coil 3 are wound, the direction of the magnetic field intensity after vector synthesis is as follows: Figure 2 shown. Figure 2 Medium H DQ1 ~H DQ8The eight groups of primary D-axis sub-coils 21 and primary Q-axis sub-coils 31 generate synthetic vectors of magnetic field strength. In this embodiment, the primary D-axis coils 2 and the primary Q-axis coils 3 are wound in a stacked alternating manner, which has symmetrical characteristics, and the self-inductance of the D-axis coils and the Q-axis coils are equal, which facilitates the subsequent compensation network parameter design. After the winding is completed, an eight-phase magnetic field is generated in the vector space. The vector magnetic field generated is as follows Figure 3 As shown, the curve of the coupling coefficient of the synthetic magnetic field when it rotates at different angles is as follows Figure 4 As shown. Figure 3 It can be seen that the vector magnetic field is more uniform and stable. Figure 4 It can be seen that the coupling coefficient is always around 0.16 during the rotation process, and its fluctuation is extremely small.

[0052] In this embodiment, the magnitude of the vectorial synthesis of the magnetic fields generated by the primary D-axis sub-coil 21 and the primary Q-axis sub-coil 31 is related to the number of turns wound on a single axis. The self-inductance of the coil can be reduced or increased by reducing or increasing the number of turns. For example, in the above simulation embodiment, The value is When the sub-coil is wound with 4 turns, it is increased to 7 turns, and the sub-coil is increased to 5 turns. This can also produce a more uniform eight-phase magnetic field and increase the coil self-inductance L. This not only takes into account the generation of a more uniform magnetic field, but also can control the coil self-inductance by changing the number of turns, which facilitates the setting of compensation network parameters.

[0053] As another embodiment of the present application, with eight groups as one module, n modules can be expanded. Then: the arc length of the primary D-axis sub-coil 21 and the primary Q-axis sub-coil 31 is adjusted to C1 / 8n, the arc length of the secondary D-axis sub-coil 51 and the secondary Q-axis sub-coil 61 is adjusted to C2 / 8n, and the circumference of the n modules covering the primary annular core 1 and the secondary annular core 4 is still C1 and C2. After the expansion, the magnetic field distribution is more uniform, the magnetic field is tightly distributed between the two coils, and the magnetic field leaking outward is very small. Taking n as 4 as an example, other parameters remain unchanged, and the vector magnetic field generated is as follows Figure 5 shown.

[0054] As another embodiment of the present application, the primary D-axis coil 2 and the primary Q-axis coil 3 only need to pass current with a phase difference of 90°, and after vector synthesis, a magnetic field of any angle can be generated, and a magnetic field of any phase such as nine phases, ten phases, or eleven phases can be wound after vector synthesis.

[0055] In summary, the primary D-axis coil 2 and the primary Q-axis coil 3 in this application have a 90° phase difference, which generates a decoupled magnetic field. Power will not be transmitted between the two primary coils. Unlike the bipolar magnetic field generated by the traditional DD coil, which is perpendicular to the center of the coil and inward or outward, the magnetic field generated by the primary D-axis coil 2 and the primary Q-axis coil 3 in this application is more uniform and stable after vector synthesis. It is less affected by the offset caused by the metal shell and coaxial rotation, and is suitable for rotating wireless power transmission devices that require metal shell protection. At the same time, by changing the number of sub-coils, the number of turns and the winding direction, various self-inductance and mutual inductance requirements can be met.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A magnetic coupling mechanism suitable for coaxial rotational wireless power transmission, comprising a primary component and a secondary component coaxially arranged, characterized in that: The primary side component comprises a primary side annular magnetic core (1), a primary side D-axis coil (2) and a primary side Q-axis coil (3), and the phase difference between the excitation currents of the primary side D-axis coil (2) and the primary side Q-axis coil (3) is 90°; The primary D-axis coil (2) and the primary Q-axis coil (3) are stacked and wound on the outer arc surface of the primary annular magnetic core (1); the primary D-axis coil (2) and the primary Q-axis coil (3) respectively include a plurality of primary D-axis sub-coils (21) and primary Q-axis sub-coils (31) sequentially wound along the outer arc surface of the primary annular magnetic core (1); the primary D-axis sub-coils (21) and the primary Q-axis sub-coils (31) are both arc-surface rectangular coils; The secondary side component comprises a secondary side annular magnetic core (4), a secondary side D-axis coil (5) and a secondary side Q-axis coil (6); the secondary side annular magnetic core (4) is coaxially arranged with the primary side annular magnetic core (1); the secondary side D-axis coil (5) and the secondary side Q-axis coil (6) are stacked and wound on the inner arc surface of the secondary side annular magnetic core (4); the secondary side D-axis coil (5) and the secondary side Q-axis coil (6) comprise a plurality of secondary side D-axis sub-coils (51) and secondary side Q-axis sub-coils (61) wound in sequence along the inner arc surface of the primary side annular magnetic core (1); the secondary side D-axis sub-coils (51) and the secondary side Q-axis sub-coils (61) are both arc-surface rectangular coils.

2. A magnetic coupling mechanism suitable for coaxial rotational wireless power transmission according to claim 1, characterized in that: The winding wire diameters of the primary D-axis coil (2), the primary Q-axis coil (3), the secondary D-axis coil (5), and the secondary Q-axis coil (6) are the same.

3. The magnetic coupling mechanism for coaxial rotational wireless power transmission according to claim 1, characterized in that: The lengths of the arc sides of the primary D-axis sub-coil (21) and the primary Q-axis sub-coil (31) are both C1 / N p ; The lengths of the arcuate sides of the secondary side D-axis sub-coil (51) and the secondary side Q-axis sub-coil (61) are both C2 / N p , wherein the number of the primary D-axis sub-coil (21), the primary Q-axis sub-coil (31), the secondary D-axis sub-coil (51) and the secondary Q-axis sub-coil (61) is N p , C1 is the circumference of the outer arc of the primary annular magnetic core (1), and C2 is the circumference of the inner arc of the secondary annular magnetic core (4).

4. The magnetic coupling mechanism for coaxial rotational wireless power transmission according to claim 3, characterized in that: The number of turns of the i-th primary D-axis sub-coil (21), the primary Q-axis sub-coil (31), the secondary D-axis sub-coil (51) and the secondary Q-axis sub-coil (61) is: ； Where H m * is the preset magnetic field strength amplitude, N di The value of is the number of turns of the i-th primary D-axis sub-coil (21) and the secondary D-axis sub-coil (51), N qi The value of is the number of turns of the i-th primary Q-axis sub-coil (31) and the secondary Q-axis sub-coil (61), N di = 0, the i-th primary D-axis sub-coil (21) and the secondary D-axis sub-coil (51) are both single-winding wires, N qi =0, the i-th primary Q-axis sub-coil (31) and the secondary Q-axis sub-coil (61) are both single winding wires.

5. The magnetic coupling mechanism for coaxial rotational wireless power transmission according to claim 4, characterized in that: N di When it is a positive number, the i-th primary D-axis sub-coil (21) and the secondary D-axis sub-coil (51) are wound clockwise, N di When it is a negative number, the i-th primary D-axis sub-coil (21) and the secondary D-axis sub-coil (51) are wound counterclockwise; N qi When it is a positive number, the i-th primary Q-axis sub-coil (31) and the secondary Q-axis sub-coil (61) are wound clockwise, N qi When it is a negative number, the i-th primary Q-axis sub-coil (31) and the secondary Q-axis sub-coil (61) are wound counterclockwise.

6. The magnetic coupling mechanism for coaxial rotational wireless power transmission according to claim 4, characterized in that: The number of the primary D-axis sub-coil (21), the primary Q-axis sub-coil (31), the secondary D-axis sub-coil (51), and the secondary Q-axis sub-coil (61) is 8.

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