Reluctance sine type rotary transformer harmonic suppression method based on cogging optimization

Abstract

The invention discloses a reluctance sine type rotary transformer harmonic suppression method based on cogging optimization, which comprises the following steps: a reluctance sine type rotary transformer harmonic suppression initial model is built, a rotor of the initial model has two pairs of poles, a stator winding is divided into an inner layer and an outer layer, the outer layer is an excitation winding, and the inner layer is an output winding; optimizing a tooth groove of the reluctance sine type rotary transformer, changing flat top teeth into concentric arc teeth, optimizing contour parameters of a rotor and the width of a stator tooth yoke frame, and confirming the optimal range of parameter optimization; and an optimization result and finite element analysis verification are carried out, harmonic suppression is carried out through the cogging optimization design of the rotary transformer, and the performance of the reluctance sine type rotary transformer optimization model and the performance of the preliminary model are compared. By designing the concentric circle tooth crests and combining optimization of the rotor profile and the width of the stator tooth yoke frame, the sinusoidal property of an output signal is remarkably improved, harmonic distortion is reduced, and the output amplitude is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resolver, and particularly relates to a magnetic resistance sine type resolver harmonic suppression method based on slot optimization. BACKGROUND

[0002] Among all the measuring devices for obtaining the speed of motor rotor, the resolver is outstanding because it can maintain high-precision measurement in the environment of high vibration and extreme temperature. At the same time, as a special motor, the resolver has strong robustness and stability at low cost, that is, it can maintain the accuracy of its measurement under external severe disturbance. Therefore, the resolver is widely used, and is currently the key motor speed measuring equipment used in automobiles and other heavy industries.

[0003] In the rapid development of re-electrification, the developing motor needs more precise and reliable speed measuring equipment, and the requirement for the magnetic resistance sine type resolver used for rotor position measurement is also higher and higher. The magnetic resistance sine type resolver is a speed measuring special motor using the magnetic resistance effect, which is generally fixed on the rotor of the measured motor, and the rotor is synchronous with the measured motor. The traditional magnetic guide sine type resolver is composed of an excitation winding in the stator slot, a sine and cosine output winding, and a rotor. The magnetic resistance sine type resolver uses the characteristics of rotor profile or eccentricity to make the air gap present sine, that is, the magnetic resistance presents sine. When the rotor rotates, the signals of the two-phase output winding orthogonally wound on the stator tooth slot present a sine and cosine relationship with the excitation sine signal as the amplitude. The accurate position of the measured motor rotor can be obtained by reverse demodulation of the signal.

[0004] At present, the magnetic guide sine type resolver is mostly used in the market because its output voltage and harmonic distortion rate are better than those of the magnetic resistance sine type resolver. However, in fact, the magnetic resistance sine type resolver also has low cost and high reliability, and it can use leakage magnetic field to improve precision. The high-order harmonic caused by leakage magnetic field is a fatal disadvantage of the magnetic guide sine type resolver, but the slot optimization of the magnetic resistance sine type resolver can compensate the high-order harmonic by using leakage magnetic field. Therefore, it is meaningful to optimize the magnetic resistance sine type resolver, and it is very urgent to suppress the harmonic and improve the strength and accuracy of the output signal of the magnetic resistance sine type resolver.

[0005] Therefore, how to provide a magnetic resistance sine type resolver harmonic suppression method based on slot optimization has become a technical problem to be solved by the person skilled in the art. SUMMARY

[0006] To address the shortcomings of existing technologies, this invention provides a harmonic suppression method for reluctance sinusoidal rotary transformers based on tooth slot optimization. By designing concentric circular tooth tips and optimizing the rotor profile parameters and stator tooth yoke width, the sinusoidality of the output signal is significantly improved, harmonic distortion is reduced, and the output amplitude is increased, providing a new technical path for the design and application of reluctance sinusoidal rotary transformers.

[0007] The present invention solves the technical problem by adopting the following technical solution:

[0008] A harmonic suppression method for a reluctance sinusoidal rotary transformer based on slot optimization includes:

[0009] The initial model for harmonic suppression of a reluctance sinusoidal rotary transformer is constructed. The rotor of the initial model has two pairs of poles, and the stator winding is divided into inner and outer layers. The outer layer is the excitation winding, and the inner layer is the output winding.

[0010] The tooth slots of the reluctance sinusoidal rotary transformer were optimized by changing the flat-topped teeth to concentric circular arc teeth, and the rotor profile parameters and stator tooth yoke width were optimized to confirm the optimal range of parameter optimization.

[0011] The optimization results were verified by finite element analysis. Harmonic suppression was achieved through the slot optimization design of the rotary transformer. The performance of the optimized model of the reluctance sinusoidal rotary transformer was compared with that of the preliminary model.

[0012] Furthermore, before signal demodulation, the output signal is synchronously multiplied with a single-phase sinusoidal signal and then passed through a low-pass filter to obtain a bipolar signal. The amplitude of this signal is then used for demodulation. When the rotor of the rotary transformer rotates synchronously with the motor, due to the non-uniform air gap, the air gap magnetic reluctance keeps changing, causing the two sets of output windings to induce sinusoidal induced voltage signals that change with the rotor position angle. These two signals are used to calculate the rotor angle.

[0013] The output signals are respectively

[0014] e(s) = e sm cosθsin(ωt) (1)

[0015] e(c) = e sm sinθcos(ωt) (2)

[0016] Where θ is the rotor angular displacement and ωt is the time information of the input signal to the excitation winding. The amplitude of the above formula shows that the amplitude of the output signal keeps changing with the rotor position. As long as the output signal is demodulated, the position information of the motor rotor at a certain moment can be obtained, and the motor speed can be obtained through it.

[0017] Furthermore, the design method for concentric tooth tips is as follows: the outer contour line of the tooth tip is distributed on a circle with the center of the rotary transformer as the center and the straight-line distance between the tooth center and the center of the rotary transformer as the radius, and this circle and the rotor contour tangent circle formed by the outer diameter of the rotor are concentric circles.

[0018] Furthermore, the suppression of higher harmonics is mainly affected by the rotor profile parameters and the stator tooth yoke width.

[0019] Furthermore, the optimized parameters are set as stator yoke width CE and rotor profile parameter ramp. The specific formula for the rotor profile when the maximum length is d is as follows:

[0020] x=(d-ramp-ramp·cos(2πt)·sin(2πt)) (3)

[0021] y=(d-ramp-ramp·cos(2πt)·sin(2πt)) (4)

[0022] The time t is from 0 to 1, which forms the outer profile (x, y) of the rotor.

[0023] The beneficial effects of this invention are:

[0024] This invention provides a harmonic suppression method for reluctance sinusoidal rotary transformers based on tooth slot optimization. By designing concentric circular tooth tips and optimizing the rotor profile parameters and stator tooth yoke width, the sinusoidality of the output signal is significantly improved, harmonic distortion is reduced, and the output amplitude is increased, providing a new technical path for the design and application of reluctance sinusoidal rotary transformers. Attached Figure Description

[0025] Figure 1 This is a flowchart of the method of the present invention.

[0026] Figure 2 This is a schematic diagram of the principle simulation of a reluctance sinusoidal rotary transformer.

[0027] Figure 3 This is a diagram of the initial model for harmonic suppression of a reluctance sinusoidal rotary transformer.

[0028] Figure 4 This is a schematic diagram showing the tooth tip in the stator;

[0029] Figure 5 This is a comparison diagram of flat tooth tips and concentric circular tooth tips;

[0030] Figure 6 The result curve of the fundamental amplitude in parametric analysis with ramp as the variable;

[0031] Figure 7 The result curve of the harmonic distortion rate parametric analysis with ramp as the variable;

[0032] Figure 8 The curve showing the fundamental amplitude result of parametric analysis with CE as the variable;

[0033] Figure 9 For parametric analysis of harmonic distortion rate curves with CE as the variable;

[0034] Figure 10 The result diagram for modular optimization;

[0035] Figure 11 The simulation results are shown in the figure.

[0036] Figure 12 To optimize the final model diagram;

[0037] Figure 13 The final optimized model outputs a winding signal diagram;

[0038] Figure 14 The final optimized model outputs a performance graph;

[0039] Figure 15 A comparison chart showing the performance of the optimized model of the reluctance sinusoidal rotary transformer with that of the preliminary model. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Reference Appendix Figure 1 This invention provides a harmonic suppression method for a sinusoidal reluctance rotary transformer based on slot optimization, comprising:

[0042] The initial model for harmonic suppression of a reluctance sinusoidal rotary transformer is constructed. The rotor of the initial model has two pairs of poles, and the stator winding is divided into inner and outer layers. The outer layer is the excitation winding, and the inner layer is the output winding.

[0043] The tooth slots of the reluctance sinusoidal rotary transformer were optimized by changing the flat-topped teeth to concentric circular arc teeth, and the rotor profile parameters and stator tooth yoke width were optimized to confirm the optimal range of parameter optimization.

[0044] The optimization results were verified by finite element analysis. Harmonic suppression was achieved through the slot optimization design of the rotary transformer. The performance of the optimized model of the reluctance sinusoidal rotary transformer was compared with that of the preliminary model.

[0045] As a special type of motor, the reluctance sinusoidal rotary transformer has operating characteristics and structure that are highly similar to those of general motors. This design focuses on the input and output mechanisms, and optimizes the rotary transformer by studying its structure. The optimization model is established through winding design methods and a rotary transformer test platform.

[0046] Reference Appendix Figure 2 A reluctance rotary transformer uses the principle of electromagnetic induction to measure the rotor angle. As a motor speed measuring element, its output signal is used to calculate the rotor's position information. Since the output torque is zero, it can generally be considered an unloaded motor. The basic structure of a reluctance rotary transformer consists of two parts: a stator and a rotor. The rotor is a conductor fixed to the rotor of the motor being tested, allowing them to rotate coaxially and at the same speed. The stator includes three windings: a sine output winding (sin winding), a cosine output winding (cos winding), and an excitation winding (exc winding). These three windings are evenly distributed in a double layer in the stator slots. To achieve the acquisition of the induced voltage, the sine output winding and the cosine output winding need to be spatially separated by 90°.

[0047] The input signal to the stator excitation winding of a rotary transformer is a sinusoidal AC signal. Assuming the input is an excitation current signal, according to the law of electromagnetic induction, if a single-phase excitation current generates a single-phase AC excitation magnetic field in space, the direction of the generated pulsating magnetic field satisfies the right-hand screw rule with respect to the winding direction of the excitation winding. In the analysis, the axial direction of the excitation winding is generally taken as the d-axis. Therefore, there will be an excitation pulsating magnetic field on the d-axis, with a magnetic flux of Φ. The axial direction of the other set of excitation windings is taken as the q-axis. The d-axis and q-axis correspond to the direct axis and quadrature axis, respectively, and form a 90° angle in space. The spatial pulsating magnetic field generated by the excitation current is an alternating magnetic field. According to the principle of electromagnetism in a magnetic field, this magnetic field will induce an electromotive force (EMF) in all windings where magnetic flux intersect through the air gap and ferromagnetic material. The induced EMF in the sinusoidal and cosine output windings is directly output outwards.

[0048] The air gap of a sinusoidal reluctance rotary transformer is sinusoidal, while the rotor profile of a typical rotary transformer is arcsine. Due to the inverse relationship between reluctance and air gap length, the output signal of a sinusoidal reluctance rotary transformer is not sinusoidal. Without sufficient harmonic compensation, the output signal will contain a large number of high-order harmonics. Therefore, preprocessing is required to read the rotor position from the output signal. In this design, the output signal is synchronously multiplied with a single-phase sinusoidal signal before demodulation and then passed through a low-pass filter to obtain a bipolar signal. The amplitude of this signal is then used for demodulation. When the rotor of the rotary transformer rotates synchronously with the motor, the air gap reluctance is constantly changing due to the non-uniform air gap, causing the two sets of output windings to induce sinusoidal voltage signals that vary with the rotor position angle. These two signals can be used to calculate the rotor angle.

[0049] The output signals are respectively

[0050] e(s) = e sm cosθsin(ωt) (1)

[0051] e(c) = e sm sinθcos(ωt) (2)

[0052] Where θ is the rotor angular displacement and ωt is the time information of the input signal to the excitation winding. The amplitude of the above formula shows that the amplitude of the output signal keeps changing with the rotor position. As long as the output signal is demodulated, the position information of the motor rotor at a certain moment can be obtained, and the motor speed can be obtained from it.

[0053] As can be seen from the speed measurement principle of a resolver, the cogging of the resolver's teeth is a key element in realizing the speed measurement function. To achieve more accurate motor speed, this invention will focus on optimizing the cogging mechanism to further improve the resolver's accuracy and output capability. For example... Figure 3 The diagram shows the initial model for harmonic suppression of the sinusoidal reluctance rotary transformer of this invention. The rotor of this model has two pole pairs, and the stator windings are divided into inner and outer layers; the outer layer is the excitation winding, and the inner layer is the output winding. Wherein, Figure 3 (a) is the stator of a reluctance sinusoidal rotary transformer. Figure 3 (b) is the outer excitation winding of a reluctance sinusoidal rotary transformer. Figure 3 (c) is the inner output winding of a reluctance sinusoidal rotary transformer. Figure 3 (d) is the rotor of a sinusoidal reluctance rotary transformer. To achieve harmonic suppression through slot optimization and further improve output accuracy and output signal strength, this invention designs and optimizes this model.

[0054] The stator tooth tip structure of a rotary transformer is separated from the rotor only by the air gap length. It is the part of the stator structure closest to the rotor and directly affects the output performance and overall accuracy of the rotary transformer.Figure 4 As shown. The envelope amplitude and total harmonic distortion of the rotary transformer directly determine the angle sensing accuracy. To improve the performance of the rotary transformer, this invention conducts a comprehensive design of the tooth tip shape.

[0055] The tooth tip shape of magnetic permeability sinusoidal rotary transformers is mostly flat-topped, meaning that any point on the tooth is equidistant from the center of the rotary transformer, and this distance is the straight-line distance from the center of the tooth tip to the center of the rotary transformer. Flat-topped teeth have lower requirements for machining and manufacturing processes and can better ensure the output accuracy of magnetic permeability sinusoidal rotary transformers, such as... Figure 5 As shown in (a). However, the rotary transformer in this invention uses a reluctance sinusoidal rotor, which relies on leakage flux compensation to achieve the sinusoidal signal output of the rotary transformer. This is different from the working principle of the permeability sinusoidal rotor. Therefore, the flat-topped teeth are not the optimal tooth profile for the reluctance sinusoidal rotary transformer.

[0056] Expanding the stator from polar coordinates into a Cartesian coordinate system with rotation angle as the horizontal axis and length as the vertical axis reveals that although the flat-topped tooth tip has a flat cross-section in polar coordinates, it exhibits an upward curvature in Cartesian coordinates. The minimum air gap length between the tooth and rotor is maintained only at the tooth center, while the upward curvature on both sides of the tooth directly increases the air gap length with the rotor. Furthermore, the reluctance sinusoidal rotary transformer relies on the tooth tip edge to construct a leakage magnetic circuit, thereby achieving odd-order harmonic compensation. Therefore, the upward curvature of the tooth edge increases the reluctance of the main magnetic circuit passing through the rotor, while also increasing the reluctance of the leakage magnetic circuit between the teeth of the rotary transformer, thus simultaneously reducing the leakage flux and the magnetic flux of the main magnetic circuit. This suppresses the compensation effect of leakage flux on the third harmonic in the envelope and limits the envelope amplitude by reducing the magnetic flux of the main magnetic circuit.

[0057] To improve the overall performance of a sinusoidal reluctance rotary transformer, this invention replaces the traditional flat-topped teeth with a novel concentric circular tooth tip. Specifically, the outer contour of the tooth tip is distributed on a circle with the center of the rotary transformer as its center and the straight-line distance between the tooth center and the center of the rotary transformer as its radius. This circle is concentric with the rotor contour circle formed by the rotor's outer diameter. Therefore, after expanding the polar coordinate system into a rectangular coordinate system with the horizontal axis as the angle, the tooth tip of this rotary transformer appears as a flat-topped tooth in the rectangular coordinate system, thus preventing differences in air gap length at different tooth tip positions. Figure 5 As shown in (b).

[0058] By replacing the flat-topped teeth with concentric arc-shaped teeth, the magnetic resistance of the leakage flux circuit between the teeth was effectively reduced, thus improving the suppression effect of leakage flux compensation on the third harmonic of the envelope. Furthermore, the relative distance between the tooth tip edge and the rotor was reduced, which, while enhancing the leakage flux compensation effect, also increased the amplitude of the rotary transformer envelope.

[0059] Besides adjusting the stator tooth tip shape to optimize the tooth slots, the rotor tooth shape and the width of the stator yoke are also important factors affecting the performance of a reluctance sinusoidal resolver. To accurately analyze the specific impact of these factors on the resolver output, finite element modular analysis is used to intuitively determine the optimization direction, and the results demonstrate the effectiveness of the optimized parameters.

[0060] The parameters of the resolver rotor profile curve were incorporated during the modular optimization process to increase the adaptability of the optimization. Simultaneous optimization of both the stator and rotor structures ensured that the final optimization result remained unchanged despite multi-directional slotting optimization.

[0061] The width of the stator yoke refers to the difference in radius between the outer and inner circles of the stator annular portion. As the outermost structure of a reluctance sinusoidal rotary transformer, the stator yoke has magnetic flux lines passing through it during operation. Furthermore, there are interactions and interferences between the stator windings, stator teeth, and the stator yoke itself, all of which affect the final output signal. Therefore, the width of the stator yoke needs to be considered in conjunction with other aspects of the motor's structure and operating conditions. An excessively narrow stator yoke may cause distortion of the magnetic flux density, affecting the output, while an excessively wide stator yoke increases the cost of the rotary transformer and also increases ferromagnetic losses, resulting in a higher harmonic content in the output signal.

[0062] The optimized parameters are actually set as the stator yoke width CE and the rotor profile parameter ramp. The specific formula for the rotor profile when the maximum length is 19.5mm is as follows.

[0063] x=(19.5-ramp-ramp*cos(2πt)*sin(2πt)) (3)

[0064] y=(19.5-ramp-ramp*cos(2πt)*sin(2πt)) (4)

[0065] The value of t ranges from 0 to 1, which forms the outer contour of the rotor.

[0066] By setting variables, the simulation software automatically selects appropriate data sets for application and outputs results. After outputting one set of results, the software adjusts the data set based on historical results and trends, outputting the next set of model results. This process is repeated n times within the set range of variation (n is a pre-defined parameter). Based on the trend chart of the automatically generated output results, suitable parameters are selected from the final n sets of results.

[0067] Before performing module optimization, it is necessary to select suitable optimization parameters. Here, the rotor profile parameter `ramp` and the stator yoke width `CE` are selected, meaning that both the rotor shape and the stator yoke are simultaneously selected as optimization conditions. Optimizing both simultaneously increases the likelihood of module optimization convergence and the accuracy of the final optimization results. After selecting the optimization parameters, the operating range of the optimized parameters is chosen. To more intuitively and accurately observe the distribution of the optimal parameters, parametric analysis was performed. The results of the `ramp` parametric analysis are shown below. Figure 6 and Figure 7 As shown.

[0068] Parametric analysis of the model with ramp as the independent variable shows that the total harmonic frequency fluctuates slightly as ramp increases. The two lowest points in the image are around 1 and 3. The signal amplitude first increases and then decreases as ramp increases, with the peak value near ramp 1. Figure 8 For all other points near the initial ramp of 1, the ramp is 1. In cases where CE changes, it can be seen that the overall output signal amplitude of the model is relatively high when ramp is 1, which is a useful reference point. Figure 8 and Figure 9 As shown.

[0069] Based on the parametric analysis above, we selected ramp as 1 for parametric analysis of CE. The simulation results show that the amplitude of the output signal of the rotary transformer increases positively with the increase of CE; while the total harmonic rate fluctuates greatly and has many low values.

[0070] Based on the optimization objectives of increasing the output electromotive force amplitude (Amp) to 0.55 and reducing the harmonic distortion rate (THD, mainly referring to the fifth harmonic) to 0.1%, the optimal parameter results should be achieved by selecting an optimization range of CE around 12-14 and ramp around 1. Modular simulations are then performed using this as a reference.

[0071] This invention underwent two rounds of modular simulation optimization: the first round involved 864 cases to examine the overall trend and confirm that the optimal point occurred within the modular simulation range; the second round involved a smaller-scale, precise simulation optimization with 468 cases. The results graph shows a high point in the target value, indicating the occurrence of the theoretical optimal point. The target is a variable directly proportional to the fundamental value and inversely proportional to the theoretical optimum (thd), so the final optimization result requires that this parameter be as large as possible within the target range. Figure 10 The result diagram of modular optimization, Figure 10 (a) is a diagram showing the overall modular simulation results. Figure 10 (b) is a diagram of the modular simulation results for the target range.

[0072] The final result of this invention is the approximate result of 60 algorithm iterations. Because the goal is a lower ThD and a higher Fundamental, Figure 11 The red dot closest to the top left corner represents the best optimization parameters. The final selected case is ramp=1, CE=13.5mm, which means the stator yoke width is 6.7mm.

[0073] Based on the above research on tooth groove optimization starting from structural details such as tooth tip shape, stator tooth profile, and stator yoke width, this paper derives the final optimized physical model and conducts simulation analysis based on this model to ensure that it meets the parameter objectives of this paper. Furthermore, to make the optimization results more closely resemble practical applications, the output signal of the current model is filtered out by the signal processing section to remove high-order harmonics inherent in the software simulation. Finally, the performance of the current model is determined using the Fourier analysis function within the signal processing software.

[0074] The final optimized model, output signal, and output performance are as follows: Figures 12-14 As shown, the output signal's Thd is only 0.08%, meaning that higher harmonics are almost nonexistent. The proportion of the more noticeable third harmonic Mag in the output signal of the initial physical model is also less than 0.1%. This effect demonstrates that the slot optimization method used in this invention has a significant harmonic suppression effect on the rotary transformer. Slot optimization of the reluctance sinusoidal rotary transformer improves the sinusoidality of the position information by changing the reluctance of the output signal through this path, thus resulting in a lower Thd for the final output signal; maintaining the shortest air gap length increases the fundamental amplitude of the output signal. In slot optimization, changing the shape of the tooth tip, the tooth shape, the tooth width, and the length of the stator yoke all have different effects on various indicators of the output signal. The final optimized model obtained in this invention is based on multiple simulation experiments with controlled variables.

[0075] The purpose of this invention is to suppress harmonics through optimized slot design of a rotary transformer. To achieve this, the amplitude and sinusoidal nature of the output signal are improved during the optimization process. A comparison with the finite element analysis results of the initial optimized model clearly shows that the combination of stator tooth tip shape optimization and stator yoke width design significantly improves the performance of the reluctance sinusoidal rotary transformer. Furthermore, to ensure the accuracy and validity of the simulation analysis results, the remaining circuit design, winding design, and rotor design are kept under the same conditions.

[0076] The change in tooth tip shape primarily affects the spatial distribution of the air gap magnetic field between the stator and rotor, and has a secondary impact on the spatial magnetic field distribution between the stator teeth. Therefore, changing the tooth tip shape will significantly alter both the amplitude and THD of the output signal. The stator tooth yoke width optimization incorporates the stator tooth width, which mainly affects the spatial magnetic field between the slots, while having a smaller impact on the magnetic field between the air gaps. Since the function of the rotary transformer mainly relies on the fit between the slots, it can be seen during the optimization process that the stator tooth yoke and stator tooth width have a less significant impact on the rotary transformer's performance indicators than the former.

[0077] A comparison of the performance of the optimized model of the reluctance sinusoidal rotary transformer with that of the preliminary model. Figure 15 (a) and Figure 15 As shown in (b), a comparison of the two clearly shows that the most prominent third harmonic in the original preliminary physical model has been compensated, the harmonic distortion rate has been reduced, the signal is more concentrated on the fundamental frequency, and the output signal amplitude is also larger. This means that the motor control system can receive a stronger resolver output signal and measure the motor rotor position more accurately.

[0078] The current resolver model has achieved a fundamental output signal (sine envelope) amplitude of 0.58 and a total harmonic distortion (THD) of 0.08%. The performance indicators have reached the target of an output signal amplitude of 0.55 and a THD below 0.1%.

[0079] In the tests above, some errors consistently remained before and after optimization. These harmonics are likely to persist even with improvements to the stator tooth tip, rotor profile, stator tooth width, and stator yoke, requiring further improvement from other aspects. Whether it's the tooth structure, materials, or overall design, these are all internal optimizations of the rotary transformer. The potential sources of error in a rotary transformer are diverse, including machining errors, assembly errors, environmental influences, and more. These variables affecting the durability, stability, and anti-interference capabilities of the rotary transformer are equally worthy of discussion and research.

[0080] With the increasing market demand for precise motor speed measurement, this invention conducts theoretical research on a novel type of rotary transformer: the reluctance sinusoidal rotary transformer. Due to its unique advantages, the reluctance sinusoidal rotary transformer has significant application research value. Based on existing research on resolvers and motor optimization, performance optimization studies are conducted. A model of the slotted structure of the rotor and stator of the reluctance sinusoidal rotary transformer is built. Parametric analysis and finite element analysis of the slotted structure are performed on a suitable optimized physical model to derive a physical model that meets the performance objectives. A rotary transformer demodulation system that meets simulation requirements is established. The experimental results are compared with the unoptimized model to determine the influence of each structure on the resolver performance, thus satisfying the optimization objectives of this invention.

[0081] In the cogging optimization section of the reluctance sinusoidal rotary transformer, simulation optimization was performed on several specific structural details, including the tooth tip shape, stator tooth width, and stator yoke width. The tooth tip shape referenced case studies of motor tooth tips and resolver tooth tips from domestic and international testing. Finite element analysis was performed on the stator tooth width, and parametric analysis was performed on the stator yoke width to confirm the optimal range for parameter optimization. Modular simulation was applied within the stator yoke width parameter CE 13 to 15, successfully increasing the output signal amplitude to 0.58 and reducing the harmonic distortion rate (THD) to 0.08%. The mag proportions of the third and fifth harmonics were both less than 0.1%, demonstrating the significant harmonic suppression effect of this invention on the rotary transformer. Furthermore, this invention optimizes the rotor outer contour and stator yoke width together in the simulation, ensuring the harmony of the internal structure of the final optimized model.

[0082] This invention is based on the topology of a reluctance sinusoidal rotor rotary transformer. Further design research was conducted on the stator tooth tip shape of the reluctance rotary transformer, constructing a concentric circular tooth tip to replace the traditional flat tooth tip, thus improving the leakage flux compensation effect in the reluctance sinusoidal rotary transformer. Based on the concentric circular tooth tip shape, further optimization of structural parameters such as rotor profile, stator tooth width, and yoke width was carried out, improving the output voltage envelope amplitude while suppressing total harmonic distortion of the envelope, further promoting the production, design, and application of reluctance sinusoidal rotor rotary transformers.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A harmonic suppression method for a sinusoidal reluctance rotary transformer based on slot optimization, characterized in that, include: The initial model for harmonic suppression of a reluctance sinusoidal rotary transformer is constructed. The rotor of the initial model has multiple pole pairs, and the stator winding is divided into inner and outer layers. The outer layer is the excitation winding, and the inner layer is the output winding. The tooth slots of the reluctance sinusoidal rotary transformer were optimized by changing the flat-topped teeth to concentric circular arc teeth, and the rotor profile parameters and stator tooth yoke width were optimized to confirm the optimal range of parameter optimization. The optimization results were verified by finite element analysis. Harmonic suppression was achieved through the slot optimization design of the rotary transformer. The performance of the optimized model of the reluctance sinusoidal rotary transformer was compared with that of the preliminary model.

2. The harmonic suppression method for a reluctance sinusoidal rotary transformer based on slot optimization according to claim 1, characterized in that, Before signal demodulation, the output signal is synchronously multiplied with a single-phase sinusoidal signal and then passed through a low-pass filter to obtain a bipolar signal. The amplitude of this signal is then used for demodulation. When the rotor of the rotary transformer rotates synchronously with the motor, due to the non-uniform air gap, the air gap magnetic reluctance keeps changing, causing the two sets of output windings to induce a sinusoidal induced voltage signal that changes with the rotor position angle.

3. The harmonic suppression method for a sinusoidal reluctance rotary transformer based on slot optimization according to claim 2, characterized in that, The design method for concentric tooth tips is as follows: the outer contour of the tooth tip is distributed on a circle with the center of the rotary transformer as the center and the straight-line distance between the tooth center and the center of the rotary transformer as the radius, and this circle is concentric with the rotor contour circle formed by the outer diameter of the rotor.

4. A harmonic suppression method for a reluctance sinusoidal rotary transformer based on slot optimization according to claim 2 or 3, characterized in that, High-order harmonic suppression is mainly affected by rotor profile parameters and stator tooth yoke width.

5. The harmonic suppression method for a sinusoidal reluctance rotary transformer based on slot optimization according to claim 4, characterized in that, The optimized parameters are set as stator yoke width CE and rotor profile parameter ramp. The specific formula for the rotor profile when the maximum length is d is as follows: x=(d-ramp-ramp·cos(2πt)·sin(2πt)) (3) y=(d-ramp-ramp·cos(2πt)·sin(2πt)) (4) The time t is from 0 to 1, which forms the outer profile (x, y) of the rotor.

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