Rotary transformer

Abstract

The present invention provides a rotary transformer, comprising: a stator including a stator core, an input winding and an output winding wound around the stator core; a plurality of stator slots are formed on the inner sidewall of the stator core, and the plurality of stator slots are circumferentially distributed and respectively conduct the two end faces of the stator core, so that a stator tooth is formed between any two adjacent stator slots. The stator tooth includes a stator main tooth for winding the input winding and a stator sub-tooth for winding the output winding; a rotor including a rotor core, the rotor core and the stator core are sleeved with each other, wherein the ratio between the stator main tooth and the stator negative tooth is k, and 0.7 < k < 1. Through the technical solution of the present invention, the drift phenomenon of the third harmonic vector can be eliminated by reducing the actual pole arc length, and finally the purpose of improving the rotor position accuracy of the rotary transformer can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of compressors, and more particularly, to a rotary transformer. Background Art

[0002] A rotary transformer is an electromagnetic sensor, also known as a synchro resolver, which is used to measure the angular displacement and angular velocity of the rotating shaft of a rotating object. It consists of a stator and a rotor. Among them, the stator winding serves as the circular side of the transformer and receives the exciting voltage, and the rotor winding serves as the secondary side of the transformer, and an induced voltage is obtained through electromagnetic coupling. Since the primary and secondary windings of the selected transformer change their relative positions with the angular displacement of the rotor, the magnitude of its output voltage changes with the angular displacement of the rotor, and the voltage amplitude of the output winding has a sine and cosine function relationship with the rotor rotation angle.

[0003] Salient-pole rotary transformers are widely used in applications with high safety requirements, such as automotive motors, due to their simple manufacturing process, high stability, and good heat resistance. In related technologies, as Figures 1 to 6 shown, since the tooth widths of the stator teeth around which the input winding and the output winding are wound are the same, the following defects exist:

[0004] Large rotor error and low position accuracy of the rotary transformer. Summary of the Invention

[0005] In order to solve at least one of the above technical problems, an object of the present invention is to provide a rotary transformer.

[0006] To achieve the above object, an embodiment of the present invention provides a rotary transformer, including: a stator, including a stator core and an input winding and an output winding wound around the stator core. A plurality of stator slots are formed on the inner side wall of the stator core, and the plurality of stator slots are distributed circumferentially and respectively conduct the two end faces of the stator core, so that a stator tooth is formed between any two adjacent stator slots. The stator tooth includes a stator main tooth for winding the input winding and a stator sub-tooth for winding the output winding; a rotor, including a rotor core, and the rotor core and the stator core are sleeved with each other, wherein the ratio between the stator main tooth and the stator sub-tooth is k, and 0.7 < k < 1.

[0007] In this technical solution, the rotary transformer is a reluctance rotary transformer. The input winding and the output windings (including the sine winding and the cosine winding) are wound around the stator teeth of the stator core according to a specified winding method. The stator teeth are divided into main stator teeth and secondary stator teeth according to whether the winding is an input winding or an output winding. The stator is excited through the input winding, and a varying potential signal is output through the output windings. After the input winding is energized, an excitation magnetic field is generated and starts from the main stator teeth, passing through the secondary stator teeth of the adjacent output windings. As a result, the pole arc length of the actually generated excitation magnetic field is greater than the tooth width of the main stator teeth corresponding to the excitation winding, leading to a drift phenomenon in the third harmonic vector of the induced electromotive force of the input winding, reducing the measurement accuracy of the rotary transformer. By setting the width of the main stator teeth to be less than the width of the main stator teeth, the drift phenomenon of the third harmonic vector is eliminated by reducing the actual pole arc length, ultimately achieving the purpose of improving the rotor position accuracy of the rotary transformer.

[0008] In addition, the rotary transformer in the above technical solution provided by the present invention may further have the following additional technical features:

[0009] In the above technical solution, preferably, the input winding includes an excitation winding; the output windings include a sine winding and a cosine winding. Among them, two secondary stator teeth are arranged at intervals between any two adjacent excitation windings to wind the sine winding and the cosine winding respectively, and the sine winding is wound on both sides of one of any two adjacent excitation windings, and the cosine winding is wound on both sides of the other.

[0010] In this technical solution, by arranging two secondary stator teeth at intervals between any two adjacent excitation windings to wind the sine winding and the cosine winding respectively, the excitation winding, the sine winding, and the cosine winding are distributed at intervals in the circumferential direction, and the stator is excited through the excitation winding.

[0011] In addition, according to the different windings wound, the multiple stator teeth distributed in the circumferential direction can be divided into main stator teeth and secondary stator teeth. Two secondary stator teeth are arranged at intervals between two main stator teeth. Specifically, the input winding and the output windings can be divided into multiple winding units, and the multiple winding units are wound end to end in the circumferential direction. In one winding unit, the excitation winding, the sine winding, the cosine winding, the excitation winding, the cosine winding, and the sine winding are included in sequence in the counterclockwise direction, or the excitation winding, the cosine winding, the sine winding, the excitation winding, the sine winding, and the cosine winding are included in sequence in the counterclockwise direction.

[0012] Specifically, the stator excitation windings of the rotary transformer are alternately distributed at intervals of two stator secondary teeth. The excitation magnetic field generated by the energized excitation windings emits from the stator main teeth, passes through the adjacent left and right stator secondary teeth, then passes through the rotor core, and finally returns to the stator main teeth. If the widths of the stator main teeth and the stator secondary teeth are the same, the actual pole arc width generated by the excitation magnetic field is greater than the ideal pole arc width, causing the magnetic field angle to shift, resulting in a large amount of third harmonic being introduced into the output induced electromotive forces of the sine and cosine windings. By limiting the width of the stator main teeth to be less than the width of the stator secondary teeth, and the ratio between the two is k, where 0.7 < k < 1, the magnetic field angle shift caused by the actual pole arc width generated by the excitation magnetic field can be effectively corrected, thereby reducing the third harmonic in the output induced electromotive forces of the sine and cosine windings of the rotary transformer and improving the rotor position accuracy of the rotary transformer.

[0013] In any of the above technical solutions, preferably, the number of turns of the excitation winding on each stator main tooth is the same; the number of turns of the sine winding is the same as the number of turns of the cosine winding.

[0014] In this technical solution, by limiting the number of turns of the excitation winding on each stator main tooth to be the same, the stator excitation is generated uniformly, thereby realizing the uniform rotation of the rotor. By limiting the number of turns of the sine winding to be the same as the number of turns of the cosine winding, there is only a phase difference between the output electromotive force of the sine winding and the output electromotive force of the cosine winding, thereby ensuring the accurate measurement of the shaft angular displacement and angular velocity.

[0015] In any of the above technical solutions, preferably, the ideal coil electrical angle of the excitation winding on each stator main tooth, the ideal coil electrical angle of the sine winding on each stator secondary tooth, and the ideal coil electrical angle of the cosine winding on each stator secondary tooth are all β = P * 360° / S, where the output electromotive force of the rotary transformer in one rotation period is determined according to the ideal coil electrical angle, P is the number of rotor pole pairs of the rotary transformer, S is the number of stator teeth, and after the magnetic field of the excitation winding triggers from the stator main teeth, it passes through the adjacent stator secondary teeth and then returns and closes with the stator main teeth.

[0016] In this technical solution, the ideal coil electrical angle of each winding coil is determined according to the number of rotor pole pairs and the number of stator teeth of the rotary transformer to determine the corresponding ideal pole arc length, and the specific drift amount is determined according to the difference between the ideal pole arc length and the actual pole arc length, so that the optimal ratio k between the stator main teeth and the stator secondary teeth can be determined according to the specific drift amount, so as to finally achieve the purpose of eliminating the drift amount of the induced electromotive force.

[0017] In any of the above technical solutions, preferably, the number of stator teeth is an integer multiple of 12.

[0018] In this technical solution, by limiting the number of stator teeth to an integer multiple of 12, the number of exciting windings is made even, and the exciting winding, sine winding, and cosine winding are arranged regularly, so as to minimize the multiple harmonics other than the fundamental wave, ensuring that the error of rotor measurement is not too large.

[0019] In any of the above technical solutions, preferably, when the number of stator teeth is 24 and the number of rotor pole pairs of the rotary transformer is 2, the ratio between the main stator teeth and the secondary stator teeth is 0.8 < k < 0.85.

[0020] In this technical solution, as a specific arrangement, the number of stator teeth is 24, the number of rotor pole pairs of the rotary transformer is 2, and the winding arrangement along the circumference is exciting winding 1, sine winding 2, cosine winding 3, exciting winding 4, cosine winding 5, sine winding 6, exciting winding 7, sine winding 8, cosine winding 9, exciting winding 10, cosine winding 11, sine winding 12, exciting winding 13, sine winding 14, cosine winding 15, exciting winding 16, cosine winding 17, sine winding 18, exciting winding 19, sine winding 20, cosine winding 21, exciting winding 22, cosine winding 23, sine winding 24. In this structural form, by setting the ratio between the main stator teeth and the secondary stator teeth to 0.8 < k < 0.85, the position measurement accuracy of the rotary transformer can be further improved.

[0021] In any of the above technical solutions, preferably, the width of the main stator teeth is 5 mm; the width of the secondary stator teeth is 6 mm.

[0022] In this technical solution, as a preferred arrangement, the width of the main stator teeth is 5 mm; the width of the secondary stator teeth is 6 mm, that is, k = 0.83, which can minimize the third harmonic of the output electromotive force and correspondingly improve the rotor detection accuracy.

[0023] In any of the above technical solutions, preferably, the outer contour of the rotor core is configured to produce a sinusoidal trajectory of air-gap permeance variation.

[0024] In any of the above technical solutions, preferably, a limiting groove is provided on the inner side wall of the shaft hole of the rotor core; a limiting rib is provided on the outer side wall of the rotating shaft to cooperate with the limiting groove.

[0025] In this technical solution, by providing a limiting groove on the inner side wall of the shaft hole of the rotor core, correspondingly providing a limiting rib on the outer side wall of the rotating shaft to cooperate with the limiting groove, and through the interference fit between the rotor core and the rotating shaft, it is realized that under the action of the exciting magnetic field, the rotor core drives the rotating shaft to rotate, so as to measure parameters such as the rotation angle of the rotor.

[0026] In any of the above technical solutions, preferably, the stator core is formed by stacking a plurality of silicon steel sheets along the axial direction of the rotating shaft; the rotor core is formed by stacking a plurality of silicon steel sheets along the axial direction of the rotating shaft, wherein the end faces at both ends of the rotor core protrude from the end faces at both ends of the stator core along the axial direction.

[0027] The additional aspects and advantages of the present invention will become apparent in the following description section or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0029] Figure 1 FIG. shows a schematic cross-sectional structure diagram of a rotary transformer in the related art;

[0030] Figure 2 FIG. shows Figure 1 a partial unfolded schematic diagram of the stator of the rotary transformer in;

[0031] Figure 3 FIG. shows Figure 1 a schematic diagram of the potential vector of the fundamental wave of the primary side of the rotary transformer in;

[0032] Figure 4 FIG. shows Figure 1 a schematic diagram of the potential vector of the second harmonic of the rotary transformer in;

[0033] Figure 5 FIG. shows Figure 1 a schematic diagram of the potential vector of the third harmonic of the rotary transformer in;

[0034] Figure 6 FIG. shows Figure 1 a schematic diagram of the potential drift vector of the rotary transformer in;

[0035] Figure 7 FIG. shows a schematic cross-sectional structure diagram of a rotary transformer according to an embodiment of the present invention;

[0036] Figure 8 FIG. shows Figure 7 a partial unfolded schematic diagram of the stator of the rotary transformer in.

[0037] Wherein, Figure 7 the correspondence between Figure 8 the reference numerals and the component names in is:

[0038] 1 rotary transformer, 10 stator, 102 stator core, 104 exciting winding, 106 sine winding, 108 cosine winding, 20 rotor. Detailed Embodiments

[0039] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0040] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0041] As Figure 1 shown, in the prior art, the number of stator teeth is 24, the tooth widths of the main stator teeth and the secondary stator teeth are the same, and the number of rotor pole pairs of the rotary transformer is 2. The winding arrangement along the circumferential direction is the exciting winding 1, the sine winding 2, the cosine winding 3, the exciting winding 4, the cosine winding 5, the sine winding 6, the exciting winding 7, the sine winding 8, the cosine winding 9, the exciting winding 10, the cosine winding 11, the sine winding 12, the exciting winding 13, the sine winding 14, the cosine winding 15, the exciting winding 16, the cosine winding 17, the sine winding 18, the exciting winding 19, the sine winding 20, the cosine winding 21, the exciting winding 22, the cosine winding 23, and the sine winding 24.

[0042] Among them, the exciting winding 1 and the exciting winding 7 are 6 stator teeth apart, and the electrical angle between the two exciting windings is: α = 6×β = 180°.

[0043] The sine winding 24 and the sine winding 2 are wound on both adjacent sides of the exciting winding 1, and the winding direction is positive; the electrical angle of the fundamental wave of the induced electromotive force of the sine winding 24 relative to the exciting winding 1 is -30°, and the electrical angle of the fundamental wave of the induced electromotive force of the sine winding 2 relative to the exciting winding 1 is 30°; the electrical angle of the second harmonic of the induced electromotive force of the sine winding 24 relative to the exciting winding 1 is -60°, and the electrical angle of the second harmonic of the induced electromotive force of the sine winding 2 relative to the exciting winding 1 is 60°; the electrical angle of the third harmonic of the induced electromotive force of the sine winding 24 relative to the exciting winding 1 is -90°, and the electrical angle of the third harmonic of the induced electromotive force of the sine winding 2 relative to the exciting winding is 90°.

[0044] The sine winding 6 and the sine winding 8 are wound on two adjacent sides of the exciting winding 7, and the winding direction is negative; the electrical angle of the fundamental wave of the induced electromotive force of the sine winding 6 relative to the exciting winding 7 is (-30° + 180°) = 150°, and the electrical angle of the fundamental wave of the induced electromotive force of the sine winding 2 relative to the exciting winding 7 is (30° + 180°) = 210° = -150°; the electrical angle of the second harmonic of the induced electromotive force of the sine winding 6 relative to the exciting winding 7 is 150° * 2 = 300° = -60°, and the electrical angle of the second harmonic of the induced electromotive force of the sine winding 2 relative to the exciting winding 7 is 210° * 2 = 420° = 60°; the electrical angle of the third harmonic of the induced electromotive force of the sine winding 6 relative to the exciting winding 7 is 150° * 3 = 450° = 90°, and the electrical angle of the third harmonic of the induced electromotive force of the sine winding 2 relative to the exciting winding 7 is 210° * 3 = 630° = -90°.

[0045] As Figure 3 shown, it can be seen from the phasor diagram that within one electrical cycle, the fundamental wave of the sine winding is the vector superposition of the four coils of the coils 24, 2, 6, and 8. As Figure 4 shown, the second harmonics of the four coils of the sine winding cancel each other out to zero. As Figure 5 shown, the induced electromotive forces of the four coils of the third harmonic of the sine winding also cancel each other out.

[0046] Actually, as Figure 2 shown, since the tooth widths of the main stator teeth and the auxiliary stator teeth are the same, and the ideal pole arc width is equal to the stator tooth width of the exciting winding. Since the magnetic field of the adjacent exciting windings is emitted from the stator teeth of the exciting winding and passes through the stator teeth without exciting windings on two adjacent sides, the actual pole arc width emitted by the exciting magnetic field is greater than the stator tooth width of the exciting winding, resulting in an offset Δβ in the induced electromotive force of the sine winding. The vector of the third harmonic of the induced electromotive force of the sine winding has an offset. As Figure 6 shown, then the induced electromotive forces of the four coils of the third harmonic of the sine winding cannot cancel each other out and there is a component.

[0047] In order to reduce or eliminate this component of the third induced electromotive force of the sine winding, the tooth width of the main stator tooth where the exciting winding is located is reduced, so that its actual pole arc width is reduced and the offset Δβ is eliminated. Then, the third harmonic component introduced in this winding structure can be weakened, and the sinusoidality of the output electromotive force of the rotary transformer can be increased, thereby improving the position angle detection accuracy of the rotary transformer.

[0048] Next, with reference to Figure 7 and Figure 8 describe the rotary transformer according to some embodiments of the present invention to further elaborate on eliminating the offset Δβ.

[0049] As Figure 7 and Figure 8As shown, the rotary transformer 1 according to an embodiment of the present invention includes: a stator 10, including a stator core 102 and an input winding and an output winding wound around the stator core 102. A plurality of stator slots are formed on the inner side wall of the stator core 102. The plurality of stator slots are circumferentially distributed and respectively conduct the two end faces of the stator core 102, so that a stator tooth is formed between any two adjacent stator slots. The stator tooth includes a stator main tooth for winding the input winding and a stator sub-tooth for winding the output winding; a rotor 20, including a rotor core, and the rotor core and the stator core 102 are sleeved with each other. Among them, the ratio between the stator main tooth and the stator sub-tooth is k, and 0.7 < k < 1.

[0050] In this embodiment, the rotary transformer 1 is a reluctance rotary transformer 1. The input winding and the output winding (including the sine winding 106 and the cosine winding 108) are wound on the stator teeth of the stator core 102 according to a specified winding method. The stator teeth are divided into stator main teeth and stator sub-teeth according to whether the winding is an input winding or an output winding. The stator 10 is excited through the input winding, and a changing potential signal is output through the output winding. After the input winding is energized, an excitation magnetic field is generated and starts from the stator main tooth, passes through the stator sub-tooth of the adjacent output winding, so that the pole arc length of the actually generated excitation magnetic field is greater than the tooth width of the stator main tooth of the corresponding excitation winding 104, resulting in a drift phenomenon of the third harmonic vector of the induced electromotive force of the input winding, and the measurement accuracy of the rotary transformer 1. By setting the width of the stator main tooth to be smaller than the width of the stator main tooth, the drift phenomenon of the third harmonic vector is eliminated by reducing the actual pole arc length, and finally the purpose of improving the position accuracy of the rotor 20 of the rotary transformer 1 is achieved.

[0051] In addition, the rotary transformer 1 in the above embodiment provided by the present invention may further have the following additional technical features:

[0052] In the above embodiment, preferably, the input winding includes an excitation winding 104; the output winding includes a sine winding 106 and a cosine winding 108. Among them, two stator sub-teeth are arranged at intervals between any two adjacent excitation windings 104 to wind the sine winding 106 and the cosine winding 108 respectively, and the sine winding 106 is wound on both sides of one of any two adjacent excitation windings 104, and the cosine winding 108 is wound on both sides of the other.

[0053] In this embodiment, by arranging two stator sub-teeth at intervals between any two adjacent excitation windings 104 to wind the sine winding 106 and the cosine winding 108 respectively, so that the excitation winding 104, the sine winding 106 and the cosine winding 108 are circumferentially distributed at intervals, and the stator 10 is excited through the excitation winding 104.

[0054] In addition, according to different windings wound, a plurality of circumferentially distributed stator teeth can be divided into main stator teeth and auxiliary stator teeth. Two auxiliary stator teeth are arranged at intervals between two main stator teeth. Specifically, the input winding and the output winding can be divided into a plurality of winding units. The plurality of winding units are wound end to end along the circumference. In one winding unit, the exciting winding 104, sine winding 106, cosine winding 108, exciting winding 104, cosine winding 108, and sine winding 106 are included in sequence in the counterclockwise direction, or the exciting winding 104, cosine winding 108, sine winding 106, exciting winding 104, sine winding 106, and cosine winding 108 are included in sequence in the counterclockwise direction.

[0055] Specifically, the exciting windings 104 of the stator 10 of the rotary transformer 1 are alternately distributed every other two auxiliary stator teeth. The exciting magnetic field generated by the energization of the exciting winding 104 emits from the main stator teeth, passes through the adjacent left and right auxiliary stator teeth, then passes through the rotor core, and finally returns to the main stator teeth. If the widths of the main stator teeth and the auxiliary stator teeth are the same, the actual pole arc width generated by the exciting magnetic field is greater than the ideal pole arc width, causing the magnetic field angle to shift, resulting in a large amount of third harmonic introduced into the output induced electromotive force of the sine and cosine windings 108. By limiting the width of the main stator teeth to be less than the width of the auxiliary stator teeth, and the ratio between the two is k, where 0.7 < k < 1, the magnetic field angle shift caused by the actual pole arc width generated by the exciting magnetic field can be effectively corrected, thereby reducing the third harmonic in the output induced electromotive force of the sine and cosine windings 108 of the rotary transformer 1 and improving the position accuracy of the rotor 20 of the rotary transformer 1.

[0056] In any of the above embodiments, preferably, the number of turns of the exciting winding 104 on each main stator tooth is the same; the number of turns of the sine winding 106 is the same as the number of turns of the cosine winding 108.

[0057] In this embodiment, by limiting the number of turns of the exciting winding 104 on each main stator tooth to be the same, the stator 10 excitation is uniformly generated, thereby realizing the uniform rotation of the rotor 20. By limiting the number of turns of the sine winding 106 to be the same as the number of turns of the cosine winding 108, there is only a phase difference between the output electromotive force of the sine winding 106 and the output electromotive force of the cosine winding 108, thereby ensuring the accurate measurement of the shaft angular displacement and angular velocity.

[0058] In any of the above embodiments, preferably, the ideal coil electrical angle of the exciting winding 104 of each main stator tooth, the ideal coil electrical angle of the sine winding 106 on each auxiliary stator tooth, and the ideal coil electrical angle of the cosine winding 108 on each auxiliary stator tooth are all β = P * 360° / S, where the output electromotive force of the rotary transformer 1 within one rotation period is determined according to the ideal coil electrical angle, P is the number of pole pairs of the rotor 20 of the rotary transformer 1, S is the number of stator teeth, and after the magnetic field of the exciting winding 104 is triggered from the main stator tooth, it passes through the adjacent auxiliary stator teeth and then returns and closes with the main stator tooth.

[0059] In this embodiment, the ideal coil electrical angle of each winding coil is determined according to the number of pole pairs of the rotor 20 of the rotary transformer 1 and the number of stator teeth to determine the corresponding ideal pole arc length, and the specific drift amount is determined according to the difference between the ideal pole arc length and the actual pole arc length, so that the optimal ratio k between the main stator tooth and the auxiliary stator tooth can be determined according to the specific drift amount, and finally the purpose of eliminating the drift amount of the induced electromotive force can be achieved.

[0060] In any of the above embodiments, preferably, the number of stator teeth is an integer multiple of 12.

[0061] In this embodiment, by limiting the number of stator teeth to be an integer multiple of 12, the number of exciting windings 104 is made even, and the exciting winding 104, the sine winding 106, and the cosine winding 108 are arranged regularly, so that the multiple harmonics other than the fundamental wave can be reduced to the greatest extent to ensure that the measurement error of the rotor 20 is not too large.

[0062] In any of the above embodiments, preferably, when the number of stator teeth is 24 and the number of pole pairs of the rotor 20 of the rotary transformer 1 is 2, the ratio between the main stator tooth and the auxiliary stator tooth is 0.8 < k < 0.85.

[0063] As Figure 7 shown, in this embodiment, as a specific arrangement method, the number of stator teeth is 24, the number of pole pairs of the rotor of the rotary transformer 1 is 2, and the winding arrangement along the circumference is exciting winding 1, sine winding 2, cosine winding 3, exciting winding 4, cosine winding 5, sine winding 6, exciting winding 7, sine winding 8, cosine winding 9, exciting winding 10, cosine winding 11, sine winding 12, exciting winding 13, sine winding 14, cosine winding 15, exciting winding 16, cosine winding 17, sine winding 18, exciting winding 19, sine winding 20, cosine winding 21, exciting winding 22, cosine winding 23, sine winding 24. In this structural form, by setting the ratio between the main stator tooth and the auxiliary stator tooth to be 0.8 < k < 0.85, the position measurement accuracy of the rotary transformer can be further improved.

[0064] As Figure 8 shown, in any of the above embodiments, preferably, the width of the main stator teeth is 5 mm; the width of the secondary stator teeth is 6 mm.

[0065] In this embodiment, as a preferred setting, the width of the main stator teeth is 5 mm; the width of the secondary stator teeth is 6 mm, that is, k = 0.83, which can minimize the third harmonic of the output electromotive force and correspondingly improve the rotor detection accuracy.

[0066] In any of the above embodiments, preferably, the outer contour of the rotor core is configured to produce a sinusoidal trajectory of the air-gap permeance change.

[0067] In any of the above embodiments, preferably, a limiting groove is formed on the inner side wall of the shaft hole of the rotor core; a limiting rib is provided on the outer side wall of the rotating shaft and is matched with the limiting groove.

[0068] In this embodiment, by forming a limiting groove on the inner side wall of the shaft hole of the rotor core, a corresponding limiting rib is provided on the outer side wall of the rotating shaft and is matched with the limiting groove, and through the interference fit between the rotor core and the rotating shaft, it is realized that under the action of the excitation magnetic field, the rotor core drives the rotating shaft to rotate, so as to measure parameters such as the rotation angle of the rotor.

[0069] In any of the above embodiments, preferably, the stator core 102 is formed by stacking a plurality of silicon steel sheets along the axial direction of the rotating shaft; the rotor core is formed by stacking a plurality of silicon steel sheets along the axial direction of the rotating shaft, wherein the two end faces of the rotor core protrude from the two end faces of the stator core 102 along the axial direction respectively.

[0070] In the present invention, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; the term "plurality" means two or more unless otherwise clearly defined. Terms such as "mounted", "connected", "connected to", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0071] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be construed as a limitation to the present invention.

[0072] In the description of this specification, the descriptions of the terms "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0073] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A rotary transformer, characterized in that, comprising: A stator, including a stator core and an input winding and an output winding wound around the stator core. A plurality of stator slots are provided on the inner side wall of the stator core. The plurality of stator slots are distributed circumferentially and respectively conduct the two end faces of the stator core, so that a stator tooth is formed between any two adjacent stator slots. The stator tooth includes a stator main tooth for winding the input winding and a stator secondary tooth for winding the output winding; A rotor, including a rotor core, and the rotor core and the stator core are sleeved with each other, wherein, the ratio between the stator main tooth and the stator secondary tooth is k, and 0.7 < k < 1; The input winding includes an exciting winding; The output winding includes a sine winding and a cosine winding; The ideal coil electrical angle of the exciting winding on each stator main tooth, the ideal coil electrical angle of the sine winding on each stator secondary tooth, and the ideal coil electrical angle of the cosine winding on each stator secondary tooth are all β = P * 360° / S, wherein, the output electromotive force of the rotary transformer in one rotation period is determined according to the ideal coil electrical angle. P is the number of rotor pole pairs of the rotary transformer, S is the number of stator teeth. After the magnetic field of the exciting winding is triggered from the stator main tooth, it passes through the adjacent stator secondary teeth and then returns and closes with the stator main tooth.

2. The rotary transformer according to claim 1, characterized in that, Two stator secondary teeth are arranged at intervals between any two adjacent exciting windings to respectively wind the sine winding and the cosine winding, and the sine winding is wound on both sides of one of any two adjacent exciting windings, and the cosine winding is wound on both sides of the other.

3. The rotary transformer according to claim 2, characterized in that, The number of turns of the exciting winding on each stator main tooth is the same; The number of turns of the sine winding is the same as the number of turns of the cosine winding.

4. The rotary transformer according to claim 1, characterized in that, The number of stator teeth is an integer multiple of 12.

5. The rotary transformer according to claim 4, characterized in that, When the number of stator teeth is 24 and the number of rotor pole pairs of the rotary transformer is 2, the ratio between the stator main tooth and the stator secondary tooth is 0.8 < k < 0.

85.

6. The rotary transformer according to claim 3, characterized in that, The width of the stator main tooth is 5 mm; The width of the stator secondary tooth is 6 mm.

7. The rotary transformer according to claim 1, characterized in that, The outer contour of the rotor core is configured to generate a sinusoidal trajectory of air-gap permeance change.

8. The rotary transformer according to claim 1, characterized in that, A limiting groove is provided on the inner side wall of the shaft hole of the rotor core.

9. The rotary transformer according to any one of claims 1 to 8, characterized in that, The stator core is formed by stacking a plurality of silicon steel sheets along the axial direction of the rotating shaft of the rotor; The rotor core is formed by stacking a plurality of silicon steel sheets along the axial direction of the rotating shaft, wherein, the end faces at both ends of the rotor core protrude axially from the end faces at both ends of the stator core respectively.

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