Rotary transformer
阅读说明：本技术 旋转式变压器 (Rotary transformer ) 是由 葛笑 万佳 于 2018-06-29 设计创作，主要内容包括：本发明提出了一种旋转变压器,包括：定子,包括定子铁芯以及绕设在定子铁芯上的输入绕组与输出绕组,定子铁芯的内侧壁上开设多个定子槽,多个定子槽沿周向分布,并分别使定子铁芯的两个端面导通,使任意两个相邻的定子槽之间形成定子齿,以分别绕设输入绕组与输出绕组；转子,包括转子铁芯；其中,定子铁芯的内侧壁与转子铁芯的外侧壁之间限定出空气间隙,在转子旋转时,空气间隙的长度δ沿周向与转子的机械转角θ满足包含三次谐波分量的正弦函数关系,并根据函数关系执行周期性改变,以限定出转子铁芯的外形。通过本发明的技术方案,在相同最大和最小气隙的情况下,能够提高旋转变压器的输出信号幅值和位置测量精度。(The present invention provides a rotary transformer, comprising: the stator comprises a stator core, an input winding and an output winding, wherein the input winding and the output winding are wound on the stator core, a plurality of stator slots are formed in the inner side wall of the stator core and are distributed along the circumferential direction, two end faces of the stator core are respectively conducted, and stator teeth are formed between any two adjacent stator slots so as to be wound with the input winding and the output winding respectively; a rotor including a rotor core; when the rotor rotates, the length delta of the air gap and the mechanical rotation angle theta of the rotor along the circumferential direction satisfy a sinusoidal function relationship containing a third harmonic component, and periodic change is executed according to the function relationship so as to limit the appearance of the rotor core. By the technical scheme of the invention, the amplitude of the output signal of the rotary transformer and the position measurement accuracy can be improved under the condition of the same maximum and minimum air gaps.)
1. A rotary transformer, comprising:
the stator comprises a stator core, and an input winding and an output winding which are wound on the stator core, wherein a plurality of stator slots are formed in the inner side wall of the stator core, are distributed along the circumferential direction and are respectively conducted on two end faces of the stator core, so that stator teeth are formed between any two adjacent stator slots, and the input winding and the output winding are respectively wound;
the rotor comprises a rotor iron core, and the rotor iron core is sleeved in the stator iron core;
when the rotor rotates, the length delta of the air gap and the mechanical rotation angle theta of the rotor meet a sine function relationship containing third harmonic components along the circumferential direction, and the air gap is periodically changed according to the function relationship so as to limit the shape of the rotor core.
2. The rotary transformer of claim 1,
the input winding comprises an excitation winding;
the output winding comprises a sine winding and a cosine winding,
and two stator teeth are arranged between any two adjacent excitation windings at intervals so as to respectively wind the sine winding and the cosine winding.
3. The rotary transformer of claim 2,
and the sine winding is wound on two sides of one of any two adjacent excitation windings, and the cosine winding is wound on the other two sides of the excitation winding.
4. The rotary transformer of claim 3,
the length δ of the air gap satisfies both a primary sinusoidal component distribution and a tertiary sinusoidal component distribution of the mechanical rotation angle θ of the rotor, that is, δ ═ f (cos (p θ), cos (3p θ)),
wherein p is the number of pole pairs of the rotor of the rotary transformer.
5. The rotary transformer of claim 3,
the number of coil turns of the excitation winding on each stator tooth is the same;
and the number of turns of the sine winding is the same as that of the cosine winding.
6. The rotary transformer of claim 4, wherein the length δ of the air gap and the mechanical angle θ of the rotor further satisfy the following equation:
wherein, deltaminFor the air chamberMinimum length of slot, K being coefficient of primary sinusoidal component, K being coefficient of tertiary sinusoidal component, 1<K<2，0<k<(K-1)。
7. The rotary transformer of claim 6,
δmin＝0.72mm，K＝1.9，k＝0.09，p＝2。
8. the rotary transformer of claim 1,
and a limiting groove is formed in the inner side wall of the shaft hole of the rotor core.
9. The rotary transformer of claim 1,
the number of the stator teeth is integral multiple of 12.
10. Rotary transformer according to any one of claims 1 to 9,
the stator core is formed by a plurality of silicon steel sheets in an axial superposition structure along the rotating shaft;
the rotor core is formed by a plurality of silicon steel sheets which are stacked along the axial direction of the rotating shaft,
the end faces of the two ends of the rotor core respectively protrude out of the end faces of the two ends of the stator core along the axial direction.
Technical Field
The invention relates to the field of transformers, in particular to a rotary transformer.
Background
The rotary transformer is an electromagnetic sensor, also called as synchronous resolver, used for measuring the angular displacement and angular speed of the rotating shaft of a rotating object, and composed of a stator and a rotor, wherein the stator winding is used as the round edge of the transformer and receives the excitation voltage, the rotor winding is used as the secondary edge of the transformer, the induced voltage is obtained through electromagnetic coupling, the size of the output voltage changes along with the angular displacement of the rotor because the primary edge and the secondary edge of the transformer are selected to change along with the relative position of the angular displacement of the rotor, and the voltage amplitude of the output winding and the rotor rotation angle are in sine and cosine function relation.
The salient pole type rotary transformer is widely applied to occasions with high safety performance requirements, such as automobile motors, due to the fact that the salient pole type rotary transformer is simple to manufacture, high in stability and good in temperature resistance. In the related art, as shown in fig. 1, the salient pole rotor of the salient pole rotary transformer generally adopts a rotor profile with a sinusoidal distribution, but has the following disadvantages:
the rotor error is large, and the position accuracy of the rotary transformer is not high.
Disclosure of Invention
In order to solve at least one of the above technical problems, an object of the present invention is to provide a rotary transformer.
In order to achieve the above object, an embodiment of the present invention provides a rotary transformer, including: the stator comprises a stator core, an input winding and an output winding, wherein the input winding and the output winding are wound on the stator core, a plurality of stator slots are formed in the inner side wall of the stator core and are distributed along the circumferential direction, two end faces of the stator core are respectively conducted, and stator teeth are formed between any two adjacent stator slots so as to be wound with the input winding and the output winding respectively; the rotor comprises a rotor iron core, and the rotor iron core is sleeved in the stator iron core; when the rotor rotates, the length delta of the air gap and the mechanical rotation angle theta of the rotor along the circumferential direction satisfy a sinusoidal function relationship containing a third harmonic component, and periodic change is executed according to the function relationship so as to limit the appearance of the rotor core.
In the technical scheme, the rotary transformer is a reluctance type rotary transformer, an input winding and an output winding (comprising a sine winding and a cosine winding) are wound on stator teeth of a stator core according to a specified winding mode to realize stator excitation through the input winding, a variable potential signal is output through the output winding, and the length delta of an air gap (namely the length of an air gap) is set to satisfy a sine function relation containing a third harmonic component along the circumferential direction and a mechanical rotation angle theta of a rotor so as to realize the injection of the third harmonic into the air gap of the rotary transformer and weaken the third harmonic of the output potential of an output end, so that the measurement error of the reluctance type rotary transformer can be reduced, and the position measurement accuracy of the rotary transformer can be improved.
The rotary transformer structurally ensures that the magnetic flux distribution in the air gap accords with the sine rule when the rotor rotates for one circle, the rotor shape is specially designed, so that the air gap magnetic field is approximate to the sine shape, and meanwhile, the injection of the third sine component is realized by improving the rotor shape.
According to the above description, it can also be understood by those skilled in the art that, with the rotor structure in the present application, under the condition that the difference between the maximum air gap length and the minimum air gap length is reduced, on the premise that the number of stator teeth is not changed and the number of winding turns is not changed, the output potential is the same as the potential output by the rotor structure in the prior art, so that when the rotor structure in the present application is adopted, the difference between the maximum air gap length and the minimum air gap length is not reduced, and when the rotor position detection accuracy is improved, the purpose of improving the output potential can be achieved, so that the operating efficiency of the rotary transformer can be improved.
In addition, in order to generate a larger output signal, the transformer rotor in the prior art is realized by increasing the difference between the maximum air gap and the minimum air gap, so that the change rate of the external dimension of the rotor is large, the requirement on the machining precision of the rotor is high, and according to the rotor of the technical scheme, the machining difficulty of the rotor can be reduced by injecting third harmonic.
In addition, the rotary transformer in the above technical solution provided by the present invention may further have the following additional technical features:
in the above technical solution, preferably, the input winding includes an excitation winding; the output winding comprises a sine winding and a cosine winding, wherein two stator teeth are arranged between any two adjacent excitation windings at intervals so as to respectively wind the sine winding and the cosine winding.
In the technical scheme, two stator teeth are arranged between any two adjacent excitation windings at intervals to respectively wind a sine winding and a cosine winding, so that the excitation windings, the sine winding and the cosine winding are distributed at intervals along the circumferential direction, stator excitation is realized by combining the excitation windings, and a change signal in a special functional relationship is formed by the output of the sine winding and the cosine winding and a mechanical rotation angle theta of a rotor, so that when a third harmonic is injected into an air gap, the improvement of the position measurement precision of the rotary transformer is realized.
Specifically, the stator teeth comprise first stator teeth for winding an excitation winding, second stator teeth for winding a sine winding and third stator teeth for winding a cosine winding, wherein one second stator tooth and one third stator tooth are arranged between any two adjacent first stator teeth.
In any of the above technical solutions, preferably, a sine winding is wound around two sides of one of any two adjacent excitation windings, and a cosine winding is wound around the other two sides of the other excitation winding.
In the technical scheme, according to winding different windings, a plurality of stator teeth distributed circumferentially can be divided into a first stator tooth, a second stator tooth and a third stator tooth, the number of the first stator tooth, the number of the second stator tooth and the number of the third stator tooth are the same, so that an excitation winding used for signal input and a sine winding and a cosine winding used for signal output are respectively wound, wherein the adjacent first stator tooth, the second stator tooth and the third stator tooth form a group of wound teeth, and the plurality of stator teeth distributed circumferentially are composed of a plurality of groups of wound teeth, so that regular winding of the reluctance type rotary transformer is realized, and the purpose of improving the measurement accuracy is achieved by combining injection of three sine components.
Specifically, the input winding and the output winding may be divided into a plurality of winding units, the plurality of winding units are connected end to end in the circumferential direction to complete winding, and in one winding unit, the excitation winding, the sine winding, the cosine winding, the excitation winding, the cosine winding and the sine winding are sequentially included 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 sequentially included in the counterclockwise direction.
In any of the above solutions, preferably, the length δ of the air gap satisfies both the first order sinusoidal component distribution and the third order sinusoidal component distribution of the mechanical rotation angle θ, i.e., δ ═ f (cos (p θ), cos (3p θ)), where p is the number of pole pairs of the rotor of the rotary transformer.
In this embodiment, the length δ of the air gap is limited while satisfying the primary and tertiary sinusoidal component distributions of the mechanical rotation angle θ, that is, δ ═ f (cos (p θ), cos (3p θ)), so that the amplitude of the primary fundamental wave of the output potential of the sine winding and the output potential of the cosine winding of the rotary transformer is equal, and the detection accuracy of the rotor position is improved by injecting the tertiary sinusoidal component of the length of the air gap.
In any of the above technical solutions, preferably, the number of turns of the coil of the excitation winding on each first stator tooth is the same; the number of turns of the sine winding is the same as that of the cosine winding.
In the technical scheme, the number of turns of the coil of the excitation winding on each first stator tooth is limited to be the same so as to uniformly generate stator excitation, thereby realizing uniform rotation of the rotor, and the number of turns of the coil of the sine winding is limited to be the same as that of the coil of the cosine winding, so that the output potential of the sine winding and the output potential of the cosine winding only have phase difference, thereby ensuring accurate measurement of angular displacement and angular speed of the rotating shaft.
In any of the above solutions, preferably, the length δ of the air gap and the mechanical angle θ of the rotor further satisfy the following formula:
In the technical scheme, the length of the air gap is changed along with the change of the mechanical angle by limiting a specific relation formula, and the rotor outline injected with the cubic sinusoidal component is obtained by combining the adjustment of the primary sinusoidal component coefficient K and the cubic sinusoidal component coefficient K, so that the aim of improving the measurement accuracy of the rotation angle is fulfilled.
In any of the above solutions, preferably, δmin＝0.72mm，K＝1.9，k＝0.09，p＝2。
In this solution, as a better real-time approach, δ is definedmin0.72mm, K1.9, K0.09, and p 2, to obtain a clear functional relationship between the length δ of the air gap and the mechanical angle θ of the rotor, thereby facilitating implementation.
As a specific real-time mode, the salient pole type rotary transformer with P ═ 2 and 24 stator teeth, i.e. 4 poles and 24 slots, in which, an excitation winding, a sine winding and a cosine winding are respectively and sequentially arranged on three adjacent teeth, and the coils of the three teeth are arranged in an array of 8 along the circumference, i.e. 8 excitation coils are arranged, each coil has 25 turns and the wire diameter is 25 turns
Rotor profile according to the application, maximum air space of rotary transformerLength delta of gapmax7.2mm, minimum length δ of air gapminWhen the rotor electrical angle error e1 after decoding by the rotary transformer is 0.76mm, the rotor electrical angle error e1 after decoding by the rotary transformer is +/-0.04 degrees, namely the rotor electrical angle error after decoding by the salient pole rotary transformer of the rotor shape injected with the three-time sine component is 3.81 percent of the rotor electrical angle error after decoding by the salient pole rotary transformer of the sine wave rotor shape in the prior art, so that the rotor error is reduced.
TABLE 1
θ(°)
Delta 1(mm) prior art
Delta 2(mm) technical scheme of the application
0
0.720
0.756
15
0.769
0.769
30
0.943
0.888
45
1.368
1.368
60
2.487
2.974
75
6.202
6.202
90
13.680
7.200
105
6.202
6.202
120
2.487
2.974
135
1.368
1.368
150
0.943
0.888
165
0.769
0.769
180
0.720
0.756
195
0.769
0.769
210
0.943
0.888
225
1.368
1.368
240
2.487
2.974
255
6.202
6.202
270
13.680
7.200
285
6.202
6.202
300
2.487
2.974
315
1.368
1.368
330
0.943
0.888
345
0.769
0.769
360
0.720
0.756
As can be seen from table 1, in the case where the stator size is the same as the prior art, the difference between the maximum air gap length and the minimum air gap length is reduced, the primary fundamental wave amplitude of the output potential of the sine winding and the output potential of the cosine winding of the rotary transformer is equal, but the detection accuracy of the rotor position is improved.
In addition, the difference value between the maximum air gap length and the minimum air gap length can be the same as that in the prior art by adjusting the inner diameter of the stator core, the output potential amplitude can be improved without increasing the number of turns of the output winding, and the detection precision of the rotor position is improved.
In any of the above solutions, preferably, the rotor core is configured as a salient pole structure according to the number of pole pairs of the rotor, so that the length δ of the air gap varies with the mechanical rotation angle θ in the circumferential direction.
In any of the above technical solutions, preferably, the inner side wall of the shaft hole of the rotor core is provided with a limit groove; the outer side wall of the rotating shaft is provided with a limiting rib matched with the limiting groove.
In any of the above solutions, the number of stator teeth is preferably an integer multiple of 12.
In any of the above technical solutions, preferably, the stator core is formed by stacking a plurality of silicon steel sheets in an axial direction of the rotating shaft; the rotor core is formed by a plurality of silicon steel sheets in an axial superposition structure along the rotating shaft. The end faces of the two ends of the rotor core respectively protrude out of the end faces of the two ends of the stator core along the axial direction.
One or more technical solutions provided in the technical solution of the present application have at least the following technical effects or advantages:
the length delta of the air gap is set to satisfy a sine function relation containing a third harmonic component with the mechanical rotation angle theta of the rotor along the circumferential direction, so that the third harmonic is injected into the air gap of the rotary transformer to weaken the third harmonic of the output potential of the output end, the measurement error of the reluctance type rotary transformer can be reduced, and the position measurement precision of the rotary transformer can be improved.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic cross-sectional view illustrating a rotor of a rotary transformer in the related art;
fig. 2 shows a schematic cross-sectional structure of a rotor of a rotary transformer according to an embodiment of the present invention;
fig. 3 shows a schematic structural diagram of a rotary transformer according to an embodiment of the present invention.
Wherein, the correspondence between the reference numbers and the part names in fig. 2 and fig. 3 is:
1 rotary transformer, 10 stators, 102 stator cores, 104 excitation windings, 106 sine windings, 108 cosine windings and 20 rotors.
Detailed Description
In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.
Rotary transformers according to some embodiments of the present invention are described below with reference to fig. 2 and 3.
As shown in fig. 2 and 3, the
In this embodiment, the
Because the rotary transformer structurally ensures that the magnetic flux distribution in the air gap accords with the sine rule when the rotor 20 rotates for one circle, the air gap magnetic field is approximate to the sine shape by specially designing the shape of the rotor 20, and simultaneously, the injection of the cubic sine component is realized by improving the shape of the rotor 20.
From the above description, it can also be understood by those skilled in the art that, as shown in fig. 2, with the rotor 20 structure in the present application, under the condition that the difference between the maximum air gap length and the minimum air gap length is reduced, under the premise that the number of stator teeth is not changed and the number of winding turns is not changed, the output potential is the same as the potential output by the rotor 20 structure in the prior art shown in fig. 1, so that while the rotor 20 structure in the present application is adopted, the difference between the maximum air gap length and the minimum air gap length is not reduced, and while the position detection accuracy of the rotor 20 is improved, the purpose of improving the output potential can be achieved, so that the operation efficiency of the rotary transformer can be improved.
In addition, in order to generate a larger output signal, the transformer rotor 20 in the prior art is implemented by increasing the difference between the maximum air gap and the minimum air gap, so that the change rate of the outer dimension of the rotor 20 is large, the requirement on the machining precision of the rotor 20 is high, and according to the rotor 20 in the technical scheme of the application, the machining difficulty of the rotor 20 can be reduced by injecting third harmonic.
In the above-described embodiment, preferably, the input winding includes the excitation winding 104; the output winding comprises a sine winding 106 and a cosine winding 108, wherein two stator teeth are arranged between any two adjacent excitation windings 104 at intervals so as to wind the sine winding 106 and the cosine winding 108 respectively.
In this embodiment, two stator teeth are arranged at intervals between any two adjacent excitation windings 104 to respectively wind the sine winding 106 and the cosine winding 108, so that the excitation windings 104, the sine winding 106 and the cosine winding 108 are distributed at intervals along the circumferential direction, stator excitation is realized by the excitation windings 104, and a change signal forming a special functional relationship with a mechanical rotation angle θ of a rotor is output by the sine winding 106 and the cosine winding 108, so that when a third harmonic is injected into an air gap, the position measurement accuracy of the
Specifically, the stator teeth include a first stator tooth wound with the excitation winding 104, a second stator tooth wound with the sine winding 106, and a third stator tooth wound with the cosine winding 108, wherein one second stator tooth and one third stator tooth are arranged between any two adjacent first stator teeth.
In any of the above embodiments, preferably, a sine winding 106 is wound on two sides of any two adjacent excitation windings 104, and a cosine winding 108 is wound on the other two sides.
In this embodiment, according to winding different windings, a plurality of circumferentially distributed stator teeth may be divided into a first stator tooth, a second stator tooth and a third stator tooth, where the number of the first stator tooth, the second stator tooth and the third stator tooth is the same, so as to wind an excitation winding 104 for signal input, and a sine winding 106 and a cosine winding 108 for signal output, respectively, where adjacent first stator tooth, second stator tooth and third stator tooth are a set of winding teeth, and the plurality of circumferentially distributed stator teeth are composed of a plurality of sets of winding teeth, so as to achieve regular winding of the reluctance type rotary transformer, and combine injection of three times of sine components, so as to achieve the purpose of improving measurement accuracy.
As shown in fig. 3, specifically, the input winding and the output winding may be divided into a plurality of winding units, the plurality of winding units are connected end to end in the circumferential direction to complete winding, and in one winding unit, the excitation winding 104, the sine winding 106, the cosine winding 108, the excitation winding 104, the cosine winding 108 and the sine winding 106 are sequentially included in the counterclockwise direction, or the excitation winding 104, the cosine winding 108, the sine winding 106, the excitation winding 104, the sine winding 106 and the cosine winding 108 are sequentially included in the counterclockwise direction.
In any of the above embodiments, preferably, the length δ of the air gap satisfies both the first order sinusoidal component distribution and the third order sinusoidal component distribution of the mechanical rotation angle θ, i.e., δ ═ f (cos (p θ), cos (3p θ)), where p is the number of pole pairs of the rotor 20 of the
In this embodiment, by defining the length δ of the air gap while satisfying the primary and tertiary sinusoidal component distributions of the mechanical rotation angle θ, that is, δ ═ f (cos (p θ), cos (3p θ)), the detection accuracy of the position of the rotor 20 is improved by injecting the tertiary sinusoidal component of the length of the air gap while achieving the same amplitude of the primary fundamental wave of the output potential of the sine winding 106 and the output potential of the cosine winding 108 of the
In any of the above embodiments, preferably, the number of coil turns of the excitation winding 104 on each first stator tooth is the same; the number of coil turns of the sine winding 106 is the same as the number of coil turns of the cosine winding 108.
In the embodiment, the number of turns of the coil of the excitation winding 104 on each first stator tooth is limited to be the same so as to uniformly generate excitation of the stator 10, thereby realizing uniform rotation of the rotor 20, and the number of turns of the coil of the sine winding 106 is limited to be the same as that of the coil of the cosine winding 108, so that the output potential of the sine winding 106 and the output potential of the cosine winding 108 only have a phase difference, thereby ensuring accurate measurement of angular displacement and angular velocity of the rotating shaft.
In any of the above embodiments, preferably, the length δ of the air gap and the mechanical angle θ of the rotor 20 further satisfy the following formula:
In this embodiment, a specific relational formula is defined to realize that the length of the air gap changes with the change of the mechanical angle, and the profile of the rotor 20 injected with the third sinusoidal component is obtained by combining the adjustment of the first sinusoidal component coefficient K and the third sinusoidal component coefficient K, so as to achieve the purpose of improving the measurement accuracy of the rotation angle.
In any of the above embodiments, preferably, δmin＝0.72mm，K＝1.9，k＝0.09，p＝2。
In this embodiment, as a preferred real-time approach, δ is definedmin0.72mm, K1.9, K0.09, and p 2, to obtain a clear functional relationship between the length δ of the air gap and the mechanical angle θ of the rotor 20, thereby facilitating implementation.
As a specific real-time mode, the salient pole type rotary transformer with P ═ 2 and 24 stator teeth, i.e. 4 poles and 24 slots, wherein, an excitation winding 104, a sine winding 106 and a cosine winding 108 are respectively and sequentially arranged on three adjacent teeth, and the coils of the three teeth are arrayed in 8 rows along the circumference, i.e. 8 excitation coils are arranged, the number of turns of each coil is 25, and the wire diameter is the same as that of the coil of each tooth0.1mm, 55 turns per coil of the sine winding 106 and the cosine winding 108, wire diameter
As shown in fig. 1, according to the prior art arrangement, the rotor core has a maximum profile dimension of 98.56mm, the minimum profile gear is 72.64mm, and the length of the maximum air gap δmax13.68mm, minimum length δ of air gapminThe electrical angle error of the rotor 20 after decoding by the rotary transformer is e1 ═ 1.05 °.
According to the rotor profile of the present application, the rotor core has a maximum profile dimension of 98.48mm, the minimum profile gear is 85.6mm, and the length δ of the maximum air gap of the rotary transformer ismax7.2mm, minimum length δ of air gapminWhen the size of the rotor 20 electrical angle error e1 after the resolver decoding is 0.76mm, the size of the rotor 20 electrical angle error e1 after the resolver decoding is ± 0.04 °, that is, the rotor 20 electrical angle error after the salient pole resolver decoding of the rotor 20 profile injected with the three-time sinusoidal component is 3.81% of the rotor 20 electrical angle error after the salient pole resolver decoding of the sine wave rotor 20 profile in the prior art, thereby reducing the rotor 20 error.
As shown in FIG. 1, the length of the air gap in the prior art is distributed sinusoidally along the circumference of the rotor profile of the salient pole rotary transformer, in which the stator has an inner diameter
where 1< K <2, in this example, K ═ 1.9.
p-pole pair number of salient pole rotor, in this embodiment p 2, i.e. the rotor comprises 2 pairs of poles.
θ — the mechanical angle of the circumferential rotation of the length of the air gap.
Fig. 2 shows the rotor profile of a salient pole rotary transformer injected with a cubic sinusoidal component, the length of the air gap in the circumferential direction being given by the formula:
where 0< K < (K-1), K is a positive number greater than 0, and in this embodiment, K is 0.09.
TABLE 1
θ(°)
Delta 1(mm) prior art
Delta 2(mm) examples of the present application
0
0.720
0.756
15
0.769
0.769
30
0.943
0.888
45
1.368
1.368
60
2.487
2.974
75
6.202
6.202
90
13.680
7.200
105
6.202
6.202
120
2.487
2.974
135
1.368
1.368
150
0.943
0.888
165
0.769
0.769
180
0.720
0.756
195
0.769
0.769
210
0.943
0.888
225
1.368
1.368
240
2.487
2.974
255
6.202
6.202
270
13.680
7.200
285
6.202
6.202
300
2.487
2.974
315
1.368
1.368
330
0.943
0.888
345
0.769
0.769
360
0.720
0.756
As can be seen from table 1, in the case where the stator 10 is the same size as the related art, the difference between the maximum air gap length and the minimum air gap length is reduced, the primary fundamental wave amplitude of the output potential of the sine winding 106 and the output potential of the cosine winding 108 of the
In addition, by adjusting the inner diameter of the stator core 102, the difference between the maximum air gap length and the minimum air gap length can be made the same as that in the prior art, and the output potential amplitude can be improved without increasing the number of turns of the output winding, and the detection precision of the position of the rotor 20 is improved.
In any of the above embodiments, the rotor core is preferably configured in a salient pole structure in accordance with the number of pole pairs of the rotor 20 such that the length δ of the air gap varies with the mechanical rotation angle θ in the circumferential direction.
In any of the above embodiments, preferably, the inner side wall of the shaft hole of the rotor core is provided with a limit groove; the outer side wall of the rotating shaft is provided with a limiting rib matched with the limiting groove.
In any of the above embodiments, preferably, the number of stator teeth is an integer multiple of 12.
In any of the above embodiments, preferably, the stator core 102 is formed by a plurality of silicon steel sheets stacked in an axial direction of the rotating shaft; the rotor core is formed by a plurality of silicon steel sheets in an axial superposition structure along the rotating shaft. The end faces of the two ends of the rotor core respectively protrude from the end faces of the two ends of the stator core 102 along the axial direction.
According to the technical scheme of the invention, the rotary transformer is a reluctance type rotary transformer, an excitation winding and an output winding (comprising a sine winding and a cosine winding) are wound on stator teeth of a stator core according to a specified winding mode, stator excitation is realized through the excitation winding, a change signal of a special functional relationship is formed by the output of the sine winding and the cosine winding and a mechanical rotation angle theta of a rotor, the length delta of an air gap is set to meet the sine functional relationship containing a third harmonic component with the mechanical rotation angle theta of the rotor along the circumferential direction, so that the third harmonic is injected into the air gap of the rotary transformer, the third harmonic of the output potential of an output end is weakened, the measurement error of the reluctance type rotary transformer can be reduced, and the position measurement precision of the rotary transformer is improved.
In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more unless expressly limited otherwise. The terms "mounted," "connected," "fixed," and the like are to be construed broadly, and for example, "connected" may be a fixed connection, a removable connection, or an integral connection; "coupled" may be direct or indirect through an intermediary. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
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