Axial excitation rotary transformer

Abstract

The invention provides an axial excitation rotary transformer. The axial excitation rotary transformer comprises a stator and a rotor, the stator is composed of an excitation winding printed PCB circuit board, a signal output winding printed PCB circuit board, a circular magnetic conductive end cover and stator teeth. The rotor is an impeller made of an iron magnet, an axial air gap length function is established based on an air gap magnetic flux fundamental wave maximization principle, accurate design of the contour of the rotor is achieved, the end face, far away from the stator, of the rotor is a reference face, the face, close to the stator, of the rotor fluctuates, and the thickness of the rotor fluctuates. The stator and the rotor of the rotary transformer are axially arranged, the axial excitation reluctance type rotary transformer is provided, the radial space in the rotary transformer cannot be occupied, the application occasion of the rotary transformer is expanded, the manufacturing cost is effectively reduced, and the structure is more reliable.

Description

Technical Field

[0001] The invention relates to the technical field of axially excited rotary transformers, and in particular to an axially excited rotary transformer. Background Art

[0002] A resolver is a motor component used for angle and position sensing. Its main function is to convert the position of a rotating machine into an electrical signal. It is widely used in aerospace, industrial automation, robotics, machine tools, and electric vehicles. The invention and development of the resolver can be traced back to the early 20th century. With the advancement of technology and the growth of application needs, it has gradually become an important precision sensor.

[0003] The traditional position measurement method of the reluctance rotary transformer cannot solve the high-frequency limitation at a conventional cost. The radial excitation rotary transformer is extended to the axial flux design. The axial topology structure reduces the overall size of the rotary transformer. The axial excitation rotary transformer is a new type of angle and position sensor. Its main feature is to achieve accurate measurement of the angular position through the axial excitation effect. Compared with the traditional rotary transformer, the axial excitation rotary transformer has the advantages of compact structure, high precision and strong anti-interference ability.

[0004] The core working principle of the axial excitation rotary transformer is to use the reluctance effect to detect the angular position of the rotor. Its structure usually includes a stator, a rotor, a magnetic circuit system and a detection circuit. There is a variable reluctance between the stator and the rotor. When the rotor rotates, the change in reluctance will cause a change in magnetic flux. The detection circuit measures the change in magnetic flux and then calculates the angular position of the rotor. Summary of the invention

[0005] The object of the present invention is to provide an axially excited rotary transformer.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides an axially excited rotary transformer, comprising: a stator and a rotor; the rotor profile development curve establishes an air gap length function based on the principle of maximizing the fundamental wave of the air gap magnetic flux, so as to realize the precise design of the rotor profile, and the rotor curved surface is a ripple that fluctuates according to the quasi-cosecant law;

[0008] Furthermore, the stator is composed of a printed PCB circuit board for the excitation winding, a double PCB circuit board for the sine output winding and the cosine output winding, a circular magnetic end cover and an axial magnetic tooth; the rotor is an axial impeller pressed from silicon steel, which is coaxially arranged with the stator at intervals, the end face of the rotor that is farther from the stator in the axial direction is the reference face, and the end face of the rotor that is closer to the stator in the axial direction is in the shape of an axial salient pole, so that the rotor thickness also fluctuates along the axial direction in the shape of a salient pole, and the rotor thickness is a function of the rotor angle, and the number of rotor pole pairs is denoted as p, the rotor mechanical angle is θ, and the rotor thickness is L(pθ). The axial air gap l(pθ) between the stator and the rotor and the rotor thickness L(pθ) satisfy the following constraint relationship:

[0009] L(pθ)=H+hl(pθ)

[0010] Among them, H is the axial distance from the bottom of the rotor to the center line of the rotor contour curve, and h is the axial distance from the stator magnetic circuit closest to the rotor to the center line of the rotor contour;

[0011] The magnetic flux in the axial air gap satisfies the following relationship:

[0012]

[0013] Among them, φ m is the alternating flux amplitude, φ0 is the average magnetic flux, A is the stator tooth surface area, μ0 is the air permeability, i is the excitation coil current, and N is the number of turns of the excitation winding on the PCB circuit board.

[0014] Furthermore, the rotor curved surface is in the shape of an axial salient pole, and the number of rotor pole pairs is 2 pairs.

[0015] Furthermore, the dual PCB circuit boards of the sine output winding and the cosine output winding in the stator are: a PCB circuit board 1 for printing the excitation winding 1 and the sine winding and a PCB circuit board 2 for printing the excitation winding 2 and the cosine winding, and the two boards are coaxially placed.

[0016] Furthermore, PCB circuit board 1 is a double-sided circuit board, with the excitation winding 1 and the sine winding printed on both sides and aligned axially, and PCB circuit board 2 is a double-sided circuit board, with the excitation winding 2 and the cosine winding printed on both sides and aligned axially; both PCB circuit boards have through holes at the center of the windings.

[0017] Furthermore, the axial magnetic conductive tooth yoke is connected to the circular magnetic conductive end cover and passes through the through holes of the PCB circuit board 1 and the PCB circuit board 2 in the axial direction.

[0018] Furthermore, the circular magnetic end cover at the bottom of the stator is in the shape of an annular groove, which completes the excitation closure together with the magnetic teeth and fixes the PCB circuit board 1 and the PCB circuit board 2. The edge of the circular magnetic end cover is provided with a lead hole for leading out the excitation winding and the signal output winding.

[0019] Furthermore, the axial magnetic conductive teeth and the circular magnetic conductive end cover are made by using a silicon steel powder manufacturing process, and the connection between the axial magnetic conductive teeth and the magnetic conductive end cover is welded and fixed.

[0020] The beneficial effects of the present invention are:

[0021] The present invention provides an axially excited rotary transformer, which replaces the stator structure of the traditional radial reluctance rotary transformer with an annular printed PCB circuit board and stator teeth, thereby reducing the volume ratio of the rotary transformer; an axial air gap length function is established based on the principle of maximizing the fundamental wave of the air gap flux, and an analytical expression of the rotor profile expansion curve is obtained through a rotor profile curve solving method, thereby realizing the precise design of the rotor profile expansion curve; the circular end cap and the stator teeth are used to plan the excitation circuit to achieve complete closure. The axially excited rotary transformer does not occupy the radial space inside the transformer, helps to expand the application occasions of the rotary transformer, effectively reduces the manufacturing cost, and has a more reliable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of an axially excited rotary transformer of the present invention;

[0023] Figure 2 is a side exploded view of an axially excited rotary transformer of the present invention;

[0024] Figure 3 It is a top view of the inner and outer rings of the rotor of the axially excited rotary transformer of the present invention;

[0025] Figure 4 is a schematic diagram of the axially excited rotary transformer rotor of the present invention;

[0026] Figure 5 It is a schematic diagram of the PCB circuit board winding of the axially excited rotary transformer of the present invention;

[0027] Figure 6 The invention discloses an axial magnetic conductive tooth and a magnetic conductive end cover of an axially excited rotary transformer. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] The rotor thickness fluctuates along the axial direction according to the salient poles, and the rotor thickness is a function of the rotor angle, given the rated parameters of the rotary transformer with axial excitation.

[0031] Step 1: Establish the constraint relationship between the rotor axial air gap l(pθ) and the rotor thickness L(pθ):

[0032] L(pθ)=H+hl(pθ)

[0033] Among them, H is the axial distance from the bottom of the rotor to the center line of the rotor contour curve, h is the axial distance from the stator magnetic circuit closest to the rotor to the center line of the rotor contour; p is the number of rotor pole pairs, which is 2 pairs, θ is the rotor mechanical angle, and the rotor axial air gap changes in a positive and negative curve;

[0034] Step 2: Establish the relationship between the magnetic flux in the air gap:

[0035]

[0036] Among them, φ m is the alternating flux amplitude, φ0 is the average magnetic flux, A is the stator tooth surface area, μ0 is the air permeability, i is the excitation coil current, and N is the number of turns of the excitation winding on the PCB circuit board.

[0037] Step 3: According to the relationship between air gap and rotor thickness: L(pθ)=H+hl(pθ)

[0038] Obtain the rotor profile curve function, and then transform the polar coordinates into a Cartesian three-dimensional coordinate system

[0039]

[0040] Among them, R1 is the inner contour circle radius on the radial plane of the rotor, R2 is the outer contour circle radius on the radial plane of the rotor, R1 = 80mm, R2 = 160mm, such as Figure 3 .

[0041] Step 4: The rotor profile of the axially excited rotary transformer is obtained, such as Figure 4 .

[0042] Furthermore, the dual PCB circuit boards of the sine output winding and the cosine output winding in the stator are: a PCB circuit board 1 for printing the excitation winding 1 and the sine winding and a PCB circuit board 2 for printing the excitation winding 2 and the cosine winding, and the two boards are coaxially placed.

[0043] Furthermore, PCB circuit board 1 is a double-sided circuit board, and the excitation winding 1 and the sine winding are printed on both sides and aligned along the axial direction. PCB circuit board 2 is a double-sided circuit board, and the excitation winding 2 and the cosine winding are printed on both sides and aligned along the axial direction. Both PCB circuit boards have through holes at the center of the windings, such as Figure 5 .

[0044] Furthermore, the sine winding on PCB circuit board 1 and the cosine winding on PCB circuit board 2 are axially spaced at an angle of 45°, in order to achieve a 90° difference in signal output, such as Figure 2 .

[0045] Furthermore, the axial magnetic conductive tooth yoke is connected to the circular magnetic conductive end cover and passes through the through holes of the PCB circuit board 1 and the PCB circuit board 2 in the axial direction.

[0046] Furthermore, the circular magnetic end cover at the bottom of the stator is in the shape of an annular groove, which completes the excitation closure together with the magnetic teeth and fixes the PCB circuit board 1 and the PCB circuit board 2. The edge of the circular magnetic end cover is provided with a lead hole for leading out the excitation winding and the signal output winding.

[0047] Furthermore, the axial magnetic conductive teeth and the circular magnetic conductive end cover are made by using a silicon steel powder manufacturing process, and the connection between the axial magnetic conductive teeth and the magnetic conductive end cover is welded and fixed.

[0048] The present invention provides an axially excited rotary transformer, which replaces the stator structure of the traditional radial reluctance rotary transformer with an annular printed PCB circuit board and stator teeth, thereby reducing the volume ratio of the rotary transformer; an axial air gap length function is established based on the principle of maximizing the fundamental wave of the air gap flux, and an analytical expression of the rotor profile expansion curve is obtained through a rotor profile curve solving method, thereby realizing the precise design of the rotor profile expansion curve; the circular end cap and the stator teeth are used to plan the excitation circuit to achieve complete closure. The axially excited rotary transformer does not occupy the radial space inside the transformer, helps to expand the application occasions of the rotary transformer, effectively reduces the manufacturing cost, and has a more reliable structure.

[0049] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. An axially excited rotary transformer, characterized in that: The stator is composed of a PCB circuit board for the excitation winding, a double PCB circuit board for the sine output winding and the cosine output winding, a circular magnetic end cover and an axial magnetic guide tooth; The rotor is an axial impeller pressed from silicon steel, and is coaxially arranged with the stator at intervals. The end face of the rotor that is axially farther from the stator is the reference face, and the end face that is axially closer to the stator is in the shape of an axial salient pole, so that the rotor thickness also fluctuates along the axial direction in the shape of a salient pole. The rotor thickness is a function of the rotor angle. The number of rotor pole pairs is p, the rotor mechanical angle is θ, and the rotor thickness is L (pθ). The axial air gap l (pθ) between the stator and the rotor and the rotor thickness L (pθ) satisfy the following constraint relationship: L(pθ)=H+hl(pθ) Among them, H is the axial distance from the bottom of the rotor to the center line of the rotor contour curve, and h is the axial distance from the stator magnetic circuit closest to the rotor to the center line of the rotor contour; The magnetic flux in the axial air gap satisfies the following relationship: Among them, φ m is the alternating flux amplitude, φ0 is the average magnetic flux, A is the stator tooth surface area, μ0 is the air permeability, i is the excitation coil current, and N is the number of turns of the excitation winding on the PCB circuit board.

2. The axially excited rotary transformer according to claim 1, characterized in that: The rotor curved surface is in the shape of an axial salient pole, and the number of rotor pole pairs is 2 pairs.

3. The axially excited rotary transformer according to claim 1, characterized in that: The double PCB circuit boards of the sine output winding and the cosine output winding in the stator are: a PCB circuit board 1 for printing the excitation winding 1 and the sine winding and a PCB circuit board 2 for printing the excitation winding 2 and the cosine winding, and the two boards are coaxially placed.

4. An axially excited rotary transformer according to claim 1 or claim 3, characterized in that: PCB circuit board 1 is a double-sided circuit board, with excitation winding 1 and sine winding printed on both sides and aligned along the axial direction. PCB circuit board 2 is a double-sided circuit board, with excitation winding 2 and cosine winding printed on both sides and aligned along the axial direction. Both PCB circuit boards have through holes at the center of the windings.

5. The axially excited rotary transformer according to claim 1, characterized in that: The axial magnetic conductive tooth yoke is connected to the circular magnetic conductive end cover and passes through the through holes of the PCB circuit board 1 and the PCB circuit board 2 in the axial direction.

6. The axially excited rotary transformer according to claim 1, characterized in that: The circular magnetic end cover at the bottom of the stator is in the shape of an annular groove, which completes the excitation closure together with the magnetic teeth and fixes the PCB circuit board 1 and the PCB circuit board 2. The edge of the circular magnetic end cover is provided with a lead hole for leading out the excitation winding and the signal output winding.

7. The axially excited rotary transformer according to claim 1, characterized in that: The axial magnetic guide teeth and the circular magnetic guide end cover are made by using a silicon steel powder manufacturing process, and the connection between the axial magnetic guide teeth and the magnetic guide end cover is welded and fixed.

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