Reluctance-based rotary transformer design method

Abstract

The invention discloses a reluctance-based rotary transformer design method, which is characterized by comprising the following steps of: establishing an electromagnetic simulation model of a rotary transformer through software; according to a corresponding relation table of the number of teeth and the number of rotor pole pairs, calculating the number of turns of windings, and adjusting the total number of turns of sine output windings to be equal to the total number of turns of cosine output windings; according to the fact that the stator assembly and the rotor assembly are not coaxial, simulation of a magnetic circuit and output voltage is conducted, a flux linkage oscillogram is drawn by collecting data, and the relation between the flux linkage oscillogram and the voltage is analyzed according to the flux linkage oscillogram; according to a flux linkage oscillogram, Fourier transform is used for carrying out frequency domain analysis on extracted waveforms, the proportion of higher harmonics to principal component waveforms is calculated, and in the design stage of a principle prototype of the reluctance type rotary transformer transmitter, the product performance can be effectively verified, so that it is ensured that the difference between the performance index of a finally designed product and a theoretical value is within 10%; therefore, the design repeatability and the experiment frequency are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of rotary transformers, and in particular to a design method of a rotary transformer based on a magnetoresistive type. Background Art

[0002] Resolvers, precision shaft angle sensors, play a vital role in modern servo systems, data transmission systems, and follow-up systems. Their unique measurement principle and precise angle conversion capabilities provide these systems with reliable and stable angle information, ensuring proper operation and efficient performance. To ensure the output windings can output standard sine and cosine waveforms, reluctance resolvers feature a bold innovation in rotor design, employing a unique "plum petal" rotor structure. This "plum petal" design is not simply aesthetically pleasing but based on profound electromagnetic principles and the need for waveform output. The relative motion between the rotor and stator is fundamental to the operation of a resolver. When the excitation winding is externally excited, it generates a varying magnetic field that travels across the air gap between the rotor and stator, inducing an electric potential in the output windings wound on the stator teeth. The "plum petal" rotor structure facilitates this electromagnetic induction process, enabling the output windings to output sine and cosine waveforms.

[0003] However, designing a "plum petal" rotor is no easy task. The curvature of the "plum petal" shape requires careful calculation and design for rotors of varying sizes and pole pairs. The magnitude of the curvature directly affects the fit between the rotor and stator, as well as the degree of output waveform distortion. Improper curvature design can lead to waveform distortion or even the inability to output sine and cosine waveforms, severely impacting the resolver's performance and accuracy.

[0004] To address this issue, the curvature of the "Plum Petal" rotor must be fully considered during the design phase. They utilized advanced electromagnetic simulation technology to simulate and analyze the coordination between the rotor and stator. This simulation visually demonstrates the waveform changes in the output windings for different curvatures. Furthermore, data analysis of the simulation results can be performed to further assess the impact of the curvature design on output waveform distortion. In addition to electromagnetic simulation, data analysis is also a key tool for optimizing the curvature design of the "Plum Petal" rotor. Summary of the Invention

[0005] The present application provides a design method for a magnetoresistive rotary transformer, which can effectively verify product performance during the prototype design stage of a magnetoresistive rotary transformer transmitter to ensure that the performance indicators of the final design are within 10% of the theoretical values, thereby reducing design repeatability and the number of experiments.

[0006] This application provides a design method for a reluctance-based rotary transformer, including:

[0007] S101, establishing an electromagnetic simulation model of the rotary transformer through software;

[0008] S102, calculating the number of winding turns based on a table showing a correspondence between the number of teeth and the number of rotor pole pairs, where the number of winding turns includes the number of turns of the excitation winding, the number of turns of the sine winding, and the number of turns of the cosine winding, and adjusting the total number of turns of the sine output winding to be equal to the total number of turns of the cosine output winding. Simultaneously, performing a magnetic circuit simulation using simulation software, taking into account the non-coaxiality factor between the stator assembly and the rotor assembly;

[0009] S103, simulating the magnetic circuit and output voltage based on the misalignment between the stator assembly and the rotor assembly, drawing a flux waveform diagram based on the collected data, and analyzing the relationship between the flux waveform diagram and the voltage based on the flux waveform diagram;

[0010] S104, performing frequency domain analysis on the extracted waveform using Fourier transform based on the magnetic flux waveform diagram, and calculating the ratio of the higher harmonics to the main component waveform;

[0011] S105: Adjust the number of winding turns, rotor forward rotation coefficient, etc. according to the simulation and analysis results.

[0012] Preferably, the working principle of the reluctance rotary transformer is based on the reluctance effect. The magnetic permeability of the reluctance material in the magnetic field changes with the change of the magnetic field strength. When the rotor rotates, the reluctance of the magnetic circuit is changed, thereby changing the induced electromotive force in the output winding.

[0013] Preferably, the formula for calculating the number of winding turns is: in, is the number of turns of the excitation, sine, and cosine windings on the 14 teeth, and the values ​​of i are 1, 2, 3...14; P is the winding base number of the excitation, sine and cosine windings; W is the number of winding turns and cycle period 2; Z is the number of teeth 14.

[0014] Preferably, the total number of turns of the sine and cosine output windings are equal, and the formula is: in, and is the number of sine and cosine winding turns on the 14 teeth.

[0015] Preferably, the relationship between the flux waveform and the voltage waveform is: Where V is the voltage, For magnetic chain.

[0016] Preferably, the relationship between the excitation voltage and the flux linkage is: in, is the magnetic flux, V 激磁 is the excitation voltage of the excitation winding.

[0017] Preferably, a magnetic line of force diagram is extracted based on the magnetic flux waveform diagram. In the magnetic line of force diagram, the magnetic lines of force form a closed loop across the teeth, and do not pass through the rotor to form a closed magnetic line of force loop in the stator pole shoe. The closed loop of magnetic lines of force formed across the teeth forms high-order harmonics, resulting in an increase in the output voltage distortion.

[0018] One or more technical solutions provided in this application have at least the following technical effects or advantages: During the prototype design phase of a reluctance resolver transmitter, product performance can be effectively verified to ensure that the final design's performance indicators are within 10% of the theoretical values, thereby reducing design repetitiveness and the number of experiments. The aforementioned method is used to detect whether the output voltage amplitude and waveform of the output winding are correct, and to determine whether the designed rotor meets requirements. This allows adjustments to the number of winding turns and the rotor's positive rotation coefficient to be made during the prototype theoretical phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a three-dimensional model diagram of a 5-pole product based on a reluctance type rotary transformer design method of the present invention;

[0020] Figure 2 Schematic diagram of the structure of a two-dimensional finite element model according to an embodiment of the present invention;

[0021] Figure 3 A diagram showing the corresponding relationship between the number of teeth and the number of rotor pole pairs according to an embodiment of the present invention;

[0022] Figure 4 Magnetic flux cloud diagram of the rotor of an embodiment of the present invention;

[0023] Figure 5 This is a cloud diagram of the working air gap magnetic flux of an embodiment of the present invention;

[0024] Figure 6 A diagram showing the number of turns of each tooth winding according to an embodiment of the present invention;

[0025] Figure 7 The waveform diagram of the excitation voltage and the excitation winding flux linkage of an embodiment of the present invention;

[0026] Figure 8 1 is a waveform diagram of the Sin phase output voltage and the Sin winding flux linkage according to an embodiment of the present invention;

[0027] Figure 9 1 is a waveform diagram of the Cos phase output voltage and the Cos winding flux linkage according to an embodiment of the present invention;

[0028] Figure 10 A magnetic field line diagram of an embodiment of the present invention;

[0029] Figure 11 is a Fourier transform diagram of the excitation voltage according to an embodiment of the present invention;

[0030] Figure 12 is a Fourier transform diagram of the magnetic flux of the excitation winding according to an embodiment of the present invention;

[0031] Figure 13 This is a Fourier transform diagram of the Sin phase magnetic flux according to an embodiment of the present invention;

[0032] Figure 14 is a Fourier transform diagram of the Sin phase output voltage according to an embodiment of the present invention;

[0033] Figure 15 This is a Fourier transform diagram of the Cos phase magnetic flux according to an embodiment of the present invention;

[0034] Figure 16 FIG. 4 is a Fourier transform diagram of the Cos phase output voltage according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] To facilitate understanding of the present invention, the present application will be described more comprehensively below with reference to the relevant drawings; the drawings show preferred embodiments of the present invention, but the present invention can be implemented in many different forms and is not limited to the embodiments described herein; on the contrary, the purpose of providing these embodiments is to enable a more thorough and comprehensive understanding of the disclosed content of the present invention.

[0036] It should be noted that the terms “vertical”, “horizontal”, “up”, “down”, “left”, “right” and similar expressions used in this document are for illustrative purposes only and do not represent the only implementation method.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains; the terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0038] Example 1: Figure 1 1 is a flow chart of a method for designing a reluctance type rotary transformer according to an embodiment of the present invention, comprising:

[0039] S101, establishing an electromagnetic simulation model of the rotary transformer through software;

[0040] Furthermore, Maxwell software was used to establish a two-dimensional finite element model of a 5-pole magnetoresistive rotary transformer. The 5-pole magnetoresistive rotary transformer has a series dual-channel structure. The two channels do not interfere with each other and have independent outputs. Each channel has its own output winding and can independently provide signals related to the rotor angle. Although the two channels are independent, their output signal characteristics are consistent. The 5-pole magnetoresistive rotary transformer has 5 pairs of magnetic poles, that is, a total of 10 magnetic poles (5 north poles and 5 south poles). The working principle of the magnetoresistive rotary transformer is based on the magnetoresistive effect, that is, the magnetic permeability of the magnetoresistive material (such as the iron core) in the magnetic field changes with the magnetic field strength. When the rotor rotates, it changes the magnetic resistance of the magnetic circuit, thereby changing the induced electromotive force in the output winding. For the plum petal-shaped rotor material, the rotor is the core component of the rotary transformer. In this product, the rotor is made of high-permeability soft magnetic alloy material, brand 1J79. This material has excellent magnetic properties, such as high magnetic permeability, low coercive force, etc., which can ensure the stable rotation of the rotor in the magnetic field and accurate angle measurement. The shape of the rotor is designed to be plum petal-shaped. This special shape helps to optimize the distribution of the magnetic field and improve the resolution and accuracy of the rotary transformer; for the stator material, the stator is also made of high-permeability soft magnetic alloy material. Material, brand 1J79, the stator and rotor work together to form the magnetic circuit of the resolver. The excellent magnetic properties of the stator material can ensure the stable transmission of the magnetic field and improve the overall performance of the resolver. As for the number of winding turns, the winding is responsible for converting the change of the magnetic field into an electrical signal. In this product, the number of winding turns should be determined according to the actual design requirements to ensure that the resolver has appropriate output sensitivity and accuracy. The winding material is φ0.8 homologous enameled wire, which has good conductivity and insulation, and can ensure the stable operation and long-term reliability of the winding. As for the excitation voltage, the effective value of the excitation voltage is set to 4V, and the frequency The frequency is 10kHz, and the voltage value of 4V can ensure that the resolver operates stably within the normal working range and provides accurate angle measurement signals. The selection of excitation voltage needs to consider factors such as the power consumption, temperature rise and output signal stability of the resolver. For the rotor speed, the rotor speed is between 0 and 15000rpm according to the product requirements. This speed range can meet the needs of most application scenarios. The selection of rotor speed needs to consider factors such as the dynamic response characteristics, measurement accuracy and service life of the resolver. In actual applications, the appropriate speed should be selected according to specific working conditions and performance requirements.

[0041] According to the product dimensions and pole number requirements, refer to the corresponding relationship between the number of teeth and the number of poles as shown below: Figure 3 As shown, the number of stator lamination teeth Z is determined to be 14 teeth, and the number of winding cycles Pw is determined to be 2.

[0042] S102, calculating the number of winding turns based on a table showing a correspondence between the number of teeth and the number of rotor pole pairs, where the number of winding turns includes the number of turns of the excitation winding, the number of turns of the sine winding, and the number of turns of the cosine winding, and adjusting the total number of turns of the sine output winding to be equal to the total number of turns of the cosine output winding. Simultaneously, performing a magnetic circuit simulation using simulation software, taking into account the non-coaxiality factor between the stator assembly and the rotor assembly;

[0043] Specifically, the formula for calculating the number of winding turns is: in, is the number of turns of the excitation, sine, and cosine windings on the 14 teeth, and the values ​​of i are 1, 2, 3...14; P is the winding base number of the excitation, sine and cosine windings; W is the number of winding turns, cycle number 2; Z is the number of teeth, 14; in order to make the maximum output amplitude of the sine and cosine output windings equal, the effective value of the output winding should be between 1.14±0.2V, the excitation voltage in the excitation winding is 4V, 10kHz, and the number of winding turns should not only meet the above formula, but also meet the following formula: Only in this way can the total number of turns of the sine and cosine output windings be equal, and then the maximum output amplitudes of the sine and cosine output windings be equal. The equal maximum output amplitudes of the sine and cosine output windings can improve the stability of the system and the consistency of system performance, making the signal more symmetrical and accurate.

[0044] Since it is impossible for the stator assembly and the rotor assembly to achieve a completely coaxial state during the actual processing, the non-coaxiality factor between the stator assembly and the rotor assembly is introduced in the magnetic circuit simulation. According to the actual processing level and the indicators clearly specified in the product design, 6 non-coaxialities are set between the stator and the rotor. The "path" here is a specific unit of measurement used to describe the degree of non-coaxiality. In actual applications, it may be necessary to convert or understand it according to the specific situation to reflect the non-coaxial conditions that the motor may encounter during actual manufacturing and use, thereby improving the accuracy and reliability of the simulation. Maxwell two-dimensional transient electromagnetic simulation software is selected as the modeling tool because its powerful electromagnetic field analysis capabilities and flexible modeling environment can meet the needs of motor magnetic circuit simulation. Through Maxwell two-dimensional transient electromagnetic simulation modeling and calculation of the number of turns of the excitation winding and output winding, the calculated output windings on the stator are as follows Figure 4As shown in the figure, during the modeling process, a simulation model was first designed based on the actual structure of the motor, including the geometry, material properties, and relative position of the stator and rotor. To ensure that the excitation winding and output winding meet the design requirements, the number of turns was calculated. The calculation of the number of turns is based on a comprehensive consideration of factors such as the motor's electromagnetic performance parameters, operating frequency, and the required output voltage and current. Through precise calculation and adjustment, we ensured that the winding configuration in the simulation model matches the actual operating conditions of the motor. Through magnetic circuit simulation, the performance and output characteristics of the motor can be more accurately predicted, including key indicators such as the motor's efficiency, power factor, torque, and speed. This helps to verify the feasibility of the design and can also identify and resolve potential problems before actual manufacturing, thus avoiding unnecessary waste and loss. In particular, considering the impact of non-coaxiality of the stator and rotor assemblies on motor performance during manufacturing, simulation can assess the specific impact of this non-coaxiality on motor performance, providing useful guidance and reference for subsequent manufacturing and assembly processes. Simulation results can also provide strong support for motor optimization design and performance improvement.

[0045] S103, simulating the magnetic circuit and output voltage based on the misalignment between the stator assembly and the rotor assembly, drawing a flux waveform diagram based on the collected data, and analyzing the relationship between the flux waveform diagram and the voltage based on the flux waveform diagram;

[0046] Furthermore, in order to reduce the calculation pressure of the software and collect more data in one cycle, the rotor speed is set to 10000r / min, which is about 0.006s / r, and the excitation frequency is 10000Hz, that is, when the rotor rotates one circle, there are 60 excitation signals working. According to the above set data, the magnetic circuit and output voltage are simulated. According to the simulation, the excitation voltage and excitation winding flux waveform, the Sin phase output voltage and Sin winding flux waveform and the Cos phase output voltage and Cos winding flux waveform are obtained, as shown in the following figure. Figure 7 、 Figure 8 and Figure 9As shown in the figure, based on a rotor speed of 10,000 r / min (approximately 6 ms / r) and a rotor with five pole pairs, it can be found that when the rotor rotates one revolution relative to the stator, the output voltage waveform changes by five cycles. From the figure, it can be seen that when the horizontal axis is 2.5 ms and the rotor rotates 0.42 revolutions relative to the stator, the output voltage waveform is approximately 2.1 cycles, which is consistent with the Sin and Cos phase voltage output characteristics of the five-pole reluctance resolver transmitter. At the same time, from the data waveform diagram, it can be seen that the peak value of the Sin and Cos phase output voltages is 1.82 V (effective value is 1.32 V), which is within the upper deviation of the output voltage of 1.14±0.2 V. Because the simulation is a purely theoretical mathematical model, the stator and rotor materials and the size and position of the winding coils (fixed value 8 for different axes) are relatively ideal. In actual situations, due to the influence of materials, coil position, processing accuracy, and heat treatment of soft magnetic materials, the Sin and Cos phase output voltages are smaller than the theoretical output voltages. Therefore, the number of turns of the Sin and Cos phase output windings is not adjusted. Figure 4 The data shown is used for winding and embedding. At the same time, from the flux waveform of each winding and the output voltage waveform, it is not difficult to see that there is a derivative relationship between the output winding flux waveform and the output voltage waveform with respect to time t: Where V is the voltage, is the flux linkage; the excitation voltage of the excitation winding has an integral relationship with the flux linkage: in, is the magnetic flux, V 激磁 is the excitation voltage of the excitation winding.

[0047] S104, performing frequency domain analysis on the extracted waveform using Fourier transform based on the magnetic flux waveform diagram, and calculating the ratio of the higher harmonics to the main component waveform;

[0048] Specifically, from Figure 5 From the magnetic force line diagram (at a certain moment), it is observed that the magnetic force lines form a closed loop across the teeth, and do not pass through the rotor, but form a closed magnetic force line loop at the stator pole shoe, resulting in a waste of excitation voltage. The closed magnetic force line loop formed across the teeth directly forms high-order harmonics, resulting in an increase in the output voltage distortion. Therefore, it is necessary to avoid the closed loop across the teeth and the closed loop formed at the pole shoe as much as possible. However, due to the characteristics of the material and the precision of the parts, the closed loop across the teeth and the closed loop formed at the pole shoe cannot be completely avoided. Therefore, it is necessary to perform Fourier analysis on the magnetic flux waveform and the output voltage waveform to indirectly determine whether the designed stator and rotor sizes are qualified. For the Fourier transform of the excitation voltage, such as Figure 11 As shown in the figure, after the excitation voltage is Fourier transformed, the voltage signal only contains an AC voltage signal with a frequency of 10kHz and an amplitude of 5.631V (effective value is 4V), and the excitation voltage has no noise. The excitation terminal voltage does not affect the voltage waveform of the Sin and Cos phase output windings; the magnetic flux generated by the excitation winding is Fourier transformed, as shown in Figure 12 As shown in the figure, the magnetic flux generated by the excitation end is mainly composed of a high-frequency signal of 10kHz and a fundamental frequency signal. The main magnetic flux signal that generates the induced voltage in the Sin and Cos phase output windings is the 10kHz magnetic flux signal generated by the excitation winding. At the same time, the coupling coefficient of the transformer is calculated to be approximately 0.5 from the fundamental frequency signal. The Fourier transform of the Sin phase includes the Fourier transform of the Sin phase magnetic flux and the Fourier transform of the Sin phase output voltage, which are respectively as shown in the figure. Figure 13 and 14 As shown, the Sin phase output winding flux waveform mainly contains the following Figure 13 The three frequency signals shown are low-frequency flux of 0.8kHz and high-frequency flux of about 10kHz. The proportion of 10kHz signal (in the total signal component) is about 50%, and the stator-rotor coupling coefficient is about 0.5. According to the Fourier transform of the sin-phase output voltage, it can be concluded that the signal with a frequency component of 0.8kHz accounts for about 7.9%, and when the stator and rotor are not on the same axis for 8 channels, the waveform distortion is 7.9%, which is within the acceptable range. For the Cos phase Fourier transform, it includes the Cos phase flux Fourier transform and the Cos phase output voltage Fourier transform, as shown in the following figure: Figure 15 and 16 As shown in the figure, since the total number of turns of the Cos phase flux is the same as that of the Sin phase flux, and they form a 90° angle only in the mechanical position, the Cos phase flux signal has the same components as the Sin flux signal, containing a low-frequency flux of 0.8kHz and a high-frequency flux of about 10kHz. The flux amplitude of 10kHz is approximately equal to the flux amplitude of 0.8kHz.

[0049] S105: Adjust the number of winding turns, rotor forward rotation coefficient, etc. according to the simulation and analysis results.

[0050] The technical solutions in the embodiments of the present application described above have at least the following technical effects or advantages: During the prototype design phase of a reluctance resolver transmitter, product performance can be effectively verified to ensure that the final design's performance indicators are within 10% of the theoretical values, thereby reducing design repetitiveness and the number of experiments. The aforementioned method is used to detect whether the output voltage amplitude and waveform of the output winding are correct, and to determine whether the designed rotor meets the requirements. This allows adjustments to the number of winding turns and the rotor's positive rotation coefficient to be made during the prototype theoretical phase.

[0051] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A design method for a reluctance-based rotary transformer, characterized in that: include: S101, establishing an electromagnetic simulation model of the rotary transformer through software; S102, calculating the number of winding turns based on a table showing a correspondence between the number of teeth and the number of rotor pole pairs, where the number of winding turns includes the number of turns of the excitation winding, the number of turns of the sine winding, and the number of turns of the cosine winding, and adjusting the total number of turns of the sine output winding to be equal to the total number of turns of the cosine output winding. Simultaneously, performing a magnetic circuit simulation using simulation software, taking into account the non-coaxiality factor between the stator assembly and the rotor assembly; S103, simulating the magnetic circuit and output voltage based on the misalignment between the stator assembly and the rotor assembly, drawing a flux waveform diagram based on the collected data, and analyzing the relationship between the flux waveform diagram and the voltage based on the flux waveform diagram; S104, performing frequency domain analysis on the extracted waveform using Fourier transform based on the magnetic flux waveform diagram, and calculating the ratio of the higher harmonics to the main component waveform; S105: Adjust the number of winding turns, rotor forward rotation coefficient, etc. according to the simulation and analysis results.

2. The design method of a reluctance-based rotary transformer according to claim 1, wherein: The working principle of the reluctance rotary transformer is based on the reluctance effect. The magnetic permeability of the reluctance material in the magnetic field changes with the change of the magnetic field strength. When the rotor rotates, the reluctance of the magnetic circuit is changed, thereby changing the induced electromotive force in the output winding.

3. The design method of a reluctance-based rotary transformer according to claim 1, wherein: The formula for calculating the number of winding turns is: in, is the number of turns of the excitation, sine, and cosine windings on the 14 teeth, and the values ​​of i are 1, 2, 3...14; P is the winding base number of the excitation, sine and cosine windings; W is the number of winding turns and cycle period 2; Z is the number of teeth 14.

4. The design method of a reluctance-based rotary transformer according to claim 1, wherein: The total number of turns of the sine and cosine output windings are equal, and the formula is: in, and is the number of turns of the sine and cosine windings on the 14 teeth.

5. The design method of a reluctance-based rotary transformer according to claim 1, wherein: The relationship between the flux waveform and the voltage waveform is: Where V is the voltage, For magnetic chain.

6. The method for designing a reluctance type rotary transformer according to claim 1, wherein: The relationship between the excitation voltage and the magnetic flux is: in, is the magnetic flux, V 激磁 is the excitation voltage of the excitation winding.

7. The method for designing a reluctance type rotary transformer according to claim 1, wherein: The magnetic force line diagram is extracted based on the magnetic flux waveform diagram. In the magnetic force line diagram, the magnetic force lines form a closed loop across the teeth, and do not pass through the rotor to form a closed magnetic force line loop in the stator pole shoe. The closed loop of magnetic force lines formed across the teeth generates high-order harmonics, resulting in increased output voltage distortion.

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