Design method of reluctance type rotary transformer

Abstract

The invention discloses a design method of a reluctance type rotary transformer. According to the method, high-permeability soft magnetic alloy is selected to manufacture stator and rotor laminations; establishing a parameterization equation of a rotor profile based on the radius of the reference circle and the sine fluctuation coefficient, and generating a plum petal-shaped rotor profile; determining a winding turn number distribution rule according to relative positions of stator tooth grooves, and accurately calculating the number of excitation and output winding turns of each tooth; and constructing an electromagnetic simulation model to extract a voltage signal, calculating a mechanical angle error through an inverse solution algorithm, and adjusting a rotor profile parameter by taking the mechanical angle error as feedback until a precision requirement is met. And the design precision and the development efficiency of the product are remarkably improved by constructing the outline of the rotor. Meanwhile, through simulation closed-loop optimization, the deviation between a product performance index and a theoretical value is controlled within 10%, so that the design repeatability and the number of experiments are reduced, and the research and development efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of rotary transformer technology, and specifically relates to a design method for a reluctance rotary transformer. Background Technology

[0002] Rotary transformers, as precision shaft angle sensors, play a crucial role in servo systems, data transmission systems, and follow-up systems. To enable the output windings of reluctance rotary transformers to output standard sine and cosine waveforms, the rotor is typically designed with a unique "petal"-shaped structure. Excited by the excitation windings, the rotor rotates, changing the air gap permeability, thereby inducing an electrical signal related to the rotational position in the output windings on the stator teeth.

[0003] However, when designing such "petal-shaped" rotors using existing technologies, designers typically need to initially determine the working air gap based on experience, and then repeatedly adjust the rotor curvature and dimensions using electromagnetic simulation technology to approximate the ideal output waveform. This trial-and-error design method is inefficient and makes it difficult to quantify the correspondence between rotor profile parameters and output accuracy. Furthermore, for resolver products with different pole pairs or different sizes, there is a lack of a universal parametric design logic to guide the precise configuration of the winding turns, resulting in high design repetition and numerous experimental verifications.

[0004] Therefore, a design method for reluctance rotary transformers based on parametric models is needed to improve the accuracy and efficiency of the design. Summary of the Invention

[0005] In view of this, the present invention provides a design method for a reluctance rotary transformer, which effectively improves the design accuracy and development efficiency of the product by establishing a rotor profile design and verifying it.

[0006] The technical solution adopted in this invention is: a design method for a reluctance rotary transformer, characterized by comprising the following steps:

[0007] S1: Select soft magnetic alloy materials with high initial permeability to fabricate stator and rotor stacks respectively;

[0008] S2: Based on the preset working air gap between the stator and the rotor, construct the rotor outline; the rotor outline is generated by superimposing a periodic sinusoidal fluctuation coefficient h that varies with the angle on the basis of the reference circle radius d, with the rotor rotation center as the origin, thereby generating a closed curve of the rotor outline in the shape of plum petals; the frequency of the periodic sinusoidal fluctuation coefficient h is related to the number of pole pairs of the rotary transformer.

[0009] S3: Based on the relative positional relationship between the stator slots and the magnetic pole center, determine the turn distribution pattern of the excitation winding and the output winding, and calculate the number of coil turns on each stator tooth;

[0010] S4: Construct an electromagnetic simulation model, extract the voltage signal of the output winding, and calculate the mechanical angle error of the rotary transformer based on the voltage signal; if the mechanical angle error exceeds the preset threshold, adjust the radius of the reference circle of the rotor profile or the amplitude of the periodic sinusoidal fluctuation component in step S2 until the error meets the requirements.

[0011] Furthermore, in step S2, the coordinates of any point on the rotor's outer contour... Satisfy the following parametric equations:

[0012]

[0013]

[0014] in:

[0015] t , For parameter variables;

[0016] d , is the radius of the rotor's reference circle, corresponding to the distance from the lowest point of the rotor to the center; b is the diameter of the rotor's center hole;

[0017] , R is the sinusoidal fluctuation coefficient, corresponding to the maximum increment of the rotor salient pole relative to the reference circle, R is the stator inner diameter, and r is the single-sided working air gap.

[0018] denoted as the number of pole pairs of the rotary transformer.

[0019] Furthermore, in step S1, the soft magnetic alloy material is selected as 1J79 permalloy material.

[0020] Furthermore, in step S3, determining the turns distribution pattern based on the relative positional relationship between the stator slots and the magnetic pole center specifically includes:

[0021] When the winding axis coincides with the center line of the stator slot, the number of turns is calculated using a standard sinusoidal sampling distribution;

[0022] When the winding axis coincides with the center line of the stator teeth, a phase compensation angle is introduced into the standard sinusoidal sampling distribution to correct the influence of tooth slot offset on the magnetic field distribution.

[0023] Furthermore, the number of winding turns on each stator tooth The calculation formula is as follows:

[0024] For the excitation winding:

[0025]

[0026] For sine output windings and cosine output windings:

[0027]

[0028]

[0029] in: , , This refers to the number of turns of the excitation, sine, and cosine windings on the teeth; ; , These are the reference number of turns for the excitation, sine, and cosine windings, respectively; This refers to the stator tooth number. ; This represents the total number of stator teeth. It is the extreme logarithm; This is the phase compensation angle; when the winding axis coincides with the stator slot centerline, When the winding axis coincides with the center line of the stator teeth, .

[0030] Furthermore, in step S4, the method for calculating the electrical angle error is as follows: multiple sampling points are selected within one electrical cycle to obtain the sinusoidal output voltage. Sum and cosine output voltage The angle is calculated using the arctangent function and then the difference between the calculated angle and the theoretical electrical angle is used to obtain the electrical angle error.

[0031] Furthermore, in step S4, the calculation process of the mechanical angle error includes the following sub-steps:

[0032] S41: Select multiple sampling points within one electrical cycle to obtain the sinusoidal output voltage at each sampling point. Sum and cosine output voltage ;

[0033] S42: Calculate the angle based on the sinusoidal and cosine output voltages, and calculate the difference between the calculated angle and the theoretical electrical angle to obtain the instantaneous electrical angle error. ;

[0034] S43: Calculate the range of instantaneous electrical angle errors at all sampling points, and combine this range with the number of pole pairs of the rotary transformer to calculate the mechanical angle error. .

[0035] Furthermore, the mechanical angle error The specific calculation formula is as follows:

[0036]

[0037] Where: p is the number of pole pairs of the rotary transformer;

[0038] Instantaneous electrical angle error The calculation formula is:

[0039]

[0040] in: , These are the sinusoidal and cosine winding output voltages obtained from simulation or actual measurement, respectively. This represents the theoretical electrical angle of the corresponding sampling point.

[0041] The beneficial effects of this invention are: by constructing the rotor's external profile, the design accuracy and development efficiency of the product are significantly improved. Simultaneously, through simulation closed-loop optimization, the deviation between the product's performance indicators and theoretical values ​​is controlled within 10%, thereby reducing design repetition and the number of experiments, and improving R&D efficiency. Attached Figure Description

[0042] Figure 1 This is a simulation model of the five-pole rotary transformer in the embodiment of the present invention;

[0043] Figure 2 The diagrams show the sinusoidal winding distribution and cosine winding distribution of the rotary transformer in this embodiment of the invention.

[0044] Figure 3 This is a magnetic flux density map in an embodiment of the present invention;

[0045] Figure 4 This is a dimensioned diagram of the stator and rotor in an embodiment of the present invention;

[0046] Figure 5 Theoretical rotor outline diagram in an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the output voltage waveform and data sampling points in the simulation verification of an embodiment of the present invention. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] like Figures 1-6 As shown, this embodiment provides a design method for a reluctance rotary transformer, which mainly includes the following steps:

[0050] S1. Determine that the rotary transformer includes a stator and a rotor arranged coaxially. Set the matching relationship between the number of stator teeth and the number of rotor pole pairs according to the application requirements, and select soft magnetic alloy materials with high initial permeability to fabricate stator laminations and rotor laminations respectively.

[0051] In step S1, the basic structure of the rotary transformer is first determined. To verify the effectiveness of the technical solution in this invention, in this embodiment, the design object is a pole pair number... , The stator and rotor assemblies, as the core components of the closed magnetic circuit, are crucial in their material selection. Considering that the reluctance rotary transformer modulates the output signal by utilizing the change in air gap permeability caused by the rotor's salient poles, the amplitude of its induced voltage is often small. To improve the sensor's output sensitivity and signal-to-noise ratio under weak excitation current, in this embodiment, both the stator and rotor laminations are preferably made of soft magnetic alloy material, specifically 1J79 permalloy. Compared to the 1J50 material or silicon steel sheets used in conventional motors, 1J79 material has extremely high initial permeability, significantly reducing iron loss and improving signal quality under weak magnetic fields. Furthermore, to ensure the uniformity of the magnetic circuit and reduce eddy current losses, the rotor laminations are stacked and pressed using a double-sided uniform adhesive coating process, rotating once every "petal" angle; the stator laminations are similarly pressed using adhesive coating and rotating once every slot.

[0052] S2: Based on the preset working air gap between the stator and rotor, construct the rotor outline.

[0053] The rotor profile is generated as follows: A periodic sinusoidal fluctuation coefficient h, varying with angle, is superimposed on the reference circle radius d, using the rotor's rotation center as the origin, thus generating a closed curve of the rotor profile resembling plum blossom petals. The frequency of the periodic sinusoidal fluctuation coefficient is related to the number of pole pairs of the rotary transformer. Specifically, as follows:

[0054] First, establish a Cartesian coordinate system with the rotor center as the origin. For example... Figure 5 As shown, the radius of the rotor's reference circle is set to... This distance corresponds to the distance from the lowest point to the center on the rotor profile. Simultaneously, the sinusoidal ripple coefficient is set to... This coefficient corresponds to the maximum increment of the rotor's salient pole height relative to the reference circle. To obtain ideal sinusoidal air gap permeability, the coordinates of any point on the rotor's outer profile... Satisfy the following parametric equations:

[0055]

[0056]

[0057] Among them, t , For parameter variables; d , is the radius of the rotor's reference circle, corresponding to the distance from the lowest point of the rotor to the center; b is the diameter of the rotor's center hole; , R is the sinusoidal fluctuation coefficient, corresponding to the maximum increment of the rotor salient pole relative to the reference circle, R is the stator inner diameter, and r is the single-sided working air gap. denoted as the number of pole pairs of the rotary transformer.

[0058] In this embodiment, the pole log number , t Therefore, the coordinates of any point on the rotor's outer contour... Satisfy the following parametric equations:

[0059]

[0060]

[0061] The physical meaning of this equation is: at the reference radius Based on this, a frequency and a pole pair number were superimposed. Related sine waves In this way, designers only need to input the above equations into CAD software or mathematical modeling software to directly generate smooth, continuous, and closed plum blossom-shaped curves, avoiding contour errors caused by manual point plotting.

[0062] By establishing parameterized equations based on the reference radius d and the sinusoidal fluctuation coefficient h, a continuous and smooth "petal" shaped rotor can be directly generated. This method ensures the smoothness of the rotor profile from the source.

[0063] S3. Based on the relative positional relationship between the stator slots and the magnetic pole center, determine the turn distribution law of the excitation winding and the output winding, and calculate the number of coil turns on each stator tooth.

[0064] In step S3, the distribution of the number of winding turns directly determines the sinusoidality of the air gap magnetomotive force, and should satisfy the following formula:

[0065]

[0066]

[0067] in: , , The number of turns of the excitation, sine, and cosine windings on the teeth; ; , These are the reference number of turns for the sine and cosine windings, respectively; This refers to the stator tooth number. ; This represents the total number of stator teeth. It is the extreme logarithm; This is the phase compensation angle; when the winding axis coincides with the stator slot centerline, When the winding axis coincides with the center line of the stator teeth, .

[0068] Because the stator windings are actually wound on the teeth, their physical axis coincides with the tooth centerline, rather than the baseline of the ideal magnetic field distribution, i.e., the slot centerline. There is a fixed spatial offset between them, corresponding to an electrical phase offset of... Introducing phase compensation angle This is precisely to pre-correct this geometric offset in the calculation of the winding turns distribution, so that the distribution of the synthetic magnetomotive force in the air gap can still maintain a standard sinusoidal law. This is one of the key design steps to achieve high-precision angle sensing.

[0069] In this embodiment, the winding axis coincides with the center line of the stator slot. , As shown in Table 1:

[0070]

[0071] The specific number of winding turns is calculated as follows:

[0072]

[0073]

[0074]

[0075] It should be noted that the reference turn ; , The determination follows the generally accepted principles of transformer voltage transformation and sinusoidal winding distribution in this field. Specifically, based on the effective value of the excitation winding voltage (4V) and the effective value of the output winding voltage (1.38V), the designers obtained the following results through electromagnetic field simulation experiments: Sine reference number of turns Cosine reference number of turns To illustrate this more clearly, we will select a few key teeth for detailed explanation:

[0076] For the first tooth, Angle 0:

[0077] Number of turns in the sinusoidal winding: turn

[0078] Number of turns in the cosine winding:

[0079] For the second tooth, :

[0080] Number of turns in the sinusoidal winding: turn

[0081] Number of turns in the cosine winding: turn

[0082] For the third tooth, :

[0083] Number of turns in the sinusoidal winding: turn

[0084] Number of turns in the cosine winding: turn

[0085] The negative sign indicates that the winding direction of the tooth is opposite to the positive direction.

[0086] S4. Construct an electromagnetic simulation model, extract the voltage signal of the output winding, and calculate the mechanical angle error of the rotary transformer based on the voltage signal. If the mechanical angle error exceeds a preset threshold, adjust the radius of the reference circle of the rotor profile or the amplitude of the periodic sinusoidal fluctuation component described in step S2 until the error meets the requirements.

[0087] The calculation process for mechanical angle error includes the following steps:

[0088] S41: Select multiple sampling points within one electrical cycle to obtain the sinusoidal output voltage at each sampling point. Sum and cosine output voltage ;

[0089] S42: Calculate the angle based on the sinusoidal and cosine output voltages, and calculate the difference between the calculated angle and the theoretical electrical angle to obtain the instantaneous electrical angle error. The formula is as follows:

[0090]

[0091] in: , These are the sinusoidal and cosine winding output voltages obtained from simulation or actual measurement, respectively. This represents the theoretical electrical angle of the corresponding sampling point.

[0092] S43: Calculate the range of instantaneous electrical angle errors at all sampling points, and combine this range with the number of pole pairs of the rotary transformer to calculate the mechanical angle error. The formula is as follows:

[0093] Where p is the number of pole pairs of the rotary transformer.

[0094] Using simulation software, such as Maxwell, a two-dimensional model is created, such as... Figure 1-4 As shown. The rotor physical speed is set to... The effective voltage applied to the excitation winding is 4V, and the excitation frequency is 10kHz. Next, a transient simulation is performed for a complete electrical cycle, for example, for a 5-pole rotary transformer corresponding to a mechanical angle of 72°, to extract the voltage data of the output winding. Figure 6 As shown, this embodiment selected 10 key sampling points for analysis. Table 2 shows the specific data obtained from selecting individual sampling points as follows:

[0095]

[0096] Sampling point 2, corresponding to a rotor rotation time of 0.58 ms: The sinusoidal output voltage obtained from the simulation. Cosine output voltage .

[0097] Sampling point 3, corresponding to a rotor rotation time of 1.28 ms: The sinusoidal output voltage obtained from the simulation. Cosine output voltage .

[0098] Utilizing instantaneous electrical angle error The calculation formula yields:

[0099]

[0100] For sampling point 2: Solve the angle The theoretical electrical angle is 52.2°, and the instantaneous electrical angle error at this time is... =50.62° - 52.2° = -1.58°. This is the maximum negative deviation within this period.

[0101] For sampling point 3: Solve the angle The theoretical electrical angle is 113.4°, and the instantaneous electrical angle error at this time is... =114.19°-113.4°=+0.79°. This is the maximum positive deviation within this period.

[0102] Finally, calculate the mechanical angle error. Using the formula:

[0103]

[0104] Substituting the above results +0.79° get:

[0105]

[0106] It should be noted that Table 2 only lists data for some key sampling points. In actual simulation verification, by combining a denser simulation step size and data processing, the final verification showed that the system error of the rotary transformer designed in this embodiment converged to 15.14'.

[0107] The results demonstrate that the parametric design method provided by this invention allows for product accuracy to meet application requirements simply by adjusting the d and h parameters, without the need for complex magnetic pole chamfering or eccentric shaping. If the calculated results do not meet the requirements, designers only need to fine-tune the sinusoidal fluctuation coefficient h in step S2 to quickly complete the iterative design. The final product performance indicators differ from the theoretical values ​​by less than 10%, reducing design repetition and the number of experiments.

Claims

1. A design method for a reluctance rotary transformer, characterized in that, Includes the following steps: S1: Select soft magnetic alloy materials with high initial permeability to fabricate stator and rotor stacks respectively; S2: Based on the preset working air gap between the stator and rotor, construct the rotor outline; The rotor profile is generated as follows: taking the rotor rotation center as the origin, a periodic sinusoidal fluctuation coefficient h that varies with the angle is superimposed on the reference circle radius d, thereby generating a closed curve of the rotor profile in the shape of plum petals; the frequency of the periodic sinusoidal fluctuation coefficient h is related to the number of pole pairs of the rotary transformer. S3: Based on the relative positional relationship between the stator slots and the magnetic pole center, determine the turn distribution pattern of the excitation winding and the output winding, and calculate the number of coil turns on each stator tooth; S4: Construct an electromagnetic simulation model, extract the voltage signal of the output winding, and calculate the mechanical angle error of the rotary transformer based on the voltage signal; if the mechanical angle error exceeds the preset threshold, adjust the radius d of the reference circle of the rotor profile or the amplitude of the periodic sinusoidal fluctuation component h in step S2 until the error meets the requirements.

2. The design method of a reluctance rotary transformer according to claim 1, characterized in that, In step S2, the coordinates of any point on the rotor's outer contour are... Satisfy the following parametric equations: in: t , For parameter variables; d , is the radius of the rotor reference circle, corresponding to the distance from the lowest point of the rotor to the center, and b is the diameter of the rotor center hole; , R is the sinusoidal fluctuation coefficient, corresponding to the maximum increment of the rotor salient pole relative to the reference circle, R is the stator inner diameter, and r is the single-sided working air gap. denoted as the number of pole pairs of the rotary transformer.

3. The design method of a reluctance rotary transformer according to claim 1, characterized in that, In step S1, the soft magnetic alloy material is selected as 1J79 permalloy.

4. The design method of a reluctance rotary transformer according to claim 1, characterized in that, In step S3, determining the turns distribution pattern based on the relative positional relationship between the stator slots and the magnetic pole center specifically includes: When the winding axis coincides with the center line of the stator slot, the number of turns is calculated using a standard sinusoidal sampling distribution; When the winding axis coincides with the center line of the stator teeth, a phase compensation angle is introduced into the standard sinusoidal sampling distribution to correct the influence of tooth slot offset on the magnetic field distribution.

5. The design method of a reluctance rotary transformer according to claim 4, characterized in that, The number of winding turns on each stator tooth The calculation formula is as follows: For the excitation winding: For sine output windings and cosine output windings: in: , , This refers to the number of turns of the excitation, sine, and cosine windings on the teeth; , , These are the reference number of turns for the excitation, sine, and cosine windings, respectively; This refers to the stator tooth number. ; This represents the total number of stator teeth. It is the extreme logarithm; This is the phase compensation angle; when the winding axis coincides with the stator slot centerline, When the winding axis coincides with the center line of the stator teeth, .

6. The design method of a reluctance rotary transformer according to claim 1, characterized in that, In step S4, the electrical angle error is calculated by selecting multiple sampling points within one electrical cycle to obtain the sinusoidal output voltage. Sum and cosine output voltage The angle is calculated using the arctangent function and then the difference between the calculated angle and the theoretical electrical angle is used to obtain the electrical angle error.

7. The design method of a reluctance rotary transformer according to claim 1, characterized in that, In step S4, the calculation process of the mechanical angle error includes the following sub-steps: S41: Select multiple sampling points within one electrical cycle to obtain the sinusoidal output voltage at each sampling point. Sum and cosine output voltage ; S42: Calculate the angle based on the sinusoidal and cosine output voltages, and calculate the difference between the calculated angle and the theoretical electrical angle to obtain the instantaneous electrical angle error. ; S43: Calculate the range of instantaneous electrical angle errors at all sampling points, and combine this range with the number of pole pairs of the rotary transformer to calculate the mechanical angle error. .

8. The design method of a reluctance rotary transformer according to claim 7, characterized in that, The mechanical angle error The specific calculation formula is as follows: Where: p is the number of pole pairs of the rotary transformer; Instantaneous electrical angle error The calculation formula is: in: , These are the sinusoidal and cosine winding output voltages obtained from simulation or actual measurement, respectively. This represents the theoretical electrical angle of the corresponding sampling point.

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