A high-performance magnetic gear transmission device for disconnector switch operating mechanism

Abstract

This invention provides a high-performance magnetic gear transmission device for disconnecting switch operating mechanisms. Its purpose is to replace the worm gear or lead screw and nut reduction devices of traditional disconnecting switch operating mechanisms with a high-performance magnetic gear transmission device, thereby achieving more reliable opening and closing of high-voltage disconnecting switch operating mechanisms. To achieve the above objective, this invention provides a high-performance magnetic gear transmission device for disconnecting switch operating mechanisms, comprising, from the outside to the inside: an outer rotor yoke, an outer rotor permanent magnet, a modulation ring with coded teeth, an inner rotor permanent magnet, and an inner rotor yoke; air gaps exist between the outer rotor and the modulation ring, and between the inner rotor and the modulation ring; wherein, the modulation ring uses a magnetic adjustment block with coded teeth for magnetization, and the permanent magnets of both the inner and outer rotors adopt a bread-shaped magnetization method, which helps to reduce non-working harmonics, thereby reducing torque pulsation.

Description

Technical Field

[0001] This invention relates to the field of magnetic gear transmission technology, and in particular to a high-performance magnetic gear transmission device for a disconnector switch operating mechanism. Background Technology

[0002] Magnetic gear transmission devices belong to the magnetic field modulation type of magnetic transmission structure. They have attracted widespread attention both domestically and internationally due to their advantages such as high torque density, high operating efficiency, overload protection, and no need for lubrication. They are mainly used in low-speed, high-torque applications, with magnetic field modulation being a key technology for high-performance magnetic gears. Currently, high-voltage disconnect switches are the most widely used and extensive high-voltage switchgear equipment in power systems. Their operating mechanism is driven by a motor-driven worm gear or lead screw-nut reducer, which in turn drives the output shaft to achieve the opening and closing process. However, worm gear or lead screw-nut reducers are prone to severe corrosion, lubrication deterioration, and increased operating resistance, leading to disconnect switches failing to operate or incomplete opening and closing, thus increasing equipment safety hazards and maintenance costs. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a high-performance magnetic gear transmission device for disconnecting switch operating mechanism, which replaces the worm gear or lead screw and nut reduction device of traditional disconnecting switch operating mechanism with a high-performance magnetic gear transmission device.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a high-performance magnetic gear transmission device for a disconnector operating mechanism, comprising, from the outside to the inside: an outer rotor yoke, an outer rotor permanent magnet, a modulation ring with coded teeth, an inner rotor permanent magnet, and an inner rotor yoke; air gaps exist between the outer rotor yoke and the modulation ring with coded teeth, and between the inner rotor yoke and the modulation ring with coded teeth; wherein, the modulation ring with coded teeth is specifically magnetized using a magnetic adjustment block with coded teeth, and both the outer rotor permanent magnet and the inner rotor permanent magnet adopt a bread-shaped magnetization method;

[0005] An optimization method combining response surface methodology and multi-objective genetic algorithm is used to perform optimization analysis on the improved magnetic gear; the process includes the following steps:

[0006] Step 1: Determine the optimization objective, optimization variables, and constraints;

[0007] Step 2: Use response surface methodology and multi-objective genetic algorithm respectively to obtain the optimal design point;

[0008] Step 3: Compare and analyze the electromagnetic performance of the optimized improved magnetic gear and the traditional magnetic gear.

[0009] 2. The high-performance magnetic gear transmission device for the operating mechanism of a disconnecting switch according to claim 1, characterized in that the expression for the spatial harmonic order generated by the inner and outer air gaps is as follows:

[0010] p m,k =|kN+mp (1)

[0012] In the formula, k = 0, ±1, ±2, ..., ∞, m = 1, 3, 5, ..., ∞, N is the number of adjusting blocks; P is the number of pole pairs of the external rotor permanent magnet. out and the number of pole pairs P of the inner rotor permanent magnet in The following relationship must be satisfied: N = P out +P in The harmonic components in the air gap have specific pole pairs and rotational speeds. The angular velocities of the harmonic components in the inner and outer air gaps are expressed as:

[0013]

[0014] In the formula, Ω m,k Ω represents the angular velocity of the spatial harmonic components. r Ω represents the angular velocity of the inner and outer rotors. s To adjust the angular velocity of the magnetic ring.

[0015] 3. The high-performance magnetic gear transmission device for the operating mechanism of a disconnecting switch according to claim 2, characterized in that a comprehensive sensitivity S(x) is introduced. i The overall sensitivity of the comprehensive variable parameters on the various objective functions is determined by establishing reasonable weighting coefficients based on the opening and closing processes of the high-performance magnetic gear transmission device used in disconnecting switches. The comprehensive sensitivity of a single variable parameter to the three optimization objective functions is then calculated, and its expression is as follows:

[0016]

[0017] In the formula, G Te It is the sensitivity coefficient of the external rotor torque, G b1 It is the sensitivity coefficient for external rotor torque pulsation; G b2 It is the sensitivity coefficient of the inner rotor torque ripple, and ω1, ω2 and ω3 are the weight coefficients of the outer rotor torque, the outer rotor torque ripple and the inner rotor torque ripple respectively, and satisfy ω1+ω2+ω3=1.

[0018] 4. The high-performance magnetic gear transmission device for a disconnector operating mechanism according to claim 3, characterized in that, based on the response surface methodology, the response model expression of the magnetic gear is as follows:

[0019]

[0020] In the formula, y(x) is the predicted value of output torque or torque ripple, n is the number of variable parameters, α is the regression coefficient, x is the variable parameter, and δ is the statistical error value.

[0021] 5. A high-performance magnetic gear transmission device for a disconnector operating mechanism according to claim 4, characterized in that the multi-objective genetic algorithm NSGA-II is combined with the finite element method to obtain the optimal design point for high output torque and low torque pulsation targets, and the electromagnetic performance of each design point in the genetic algorithm is calculated by the finite element method; the modulation ring with coded teeth remains stationary, and the high-speed inner rotor and the low-speed outer rotor rotate in opposite directions at 170 r / min and 40 r / min, respectively;

[0022] b is defined as the torque ripple coefficient, representing torque ripple, and the specific formula is as follows:

[0023]

[0024] In the formula, T max For maximum output torque, T min For minimum output torque, T ave This represents the average output torque.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention provides a high-performance magnetic gear transmission device for disconnecting switch operating mechanism, which replaces the worm gear or lead screw nut reduction device of traditional disconnecting switch operating mechanism, improves the reliability of opening and closing of high voltage disconnecting switch operating mechanism, and reduces the safety hazards and maintenance costs of electrical equipment.

[0027] 2. The high-performance magnetic gear transmission device for disconnecting switch operating mechanisms provided by this invention improves the structure of the rotor permanent magnet. Both the inner and outer rotor permanent magnets adopt a bread-shaped magnetization method, which results in higher amplitude of the air gap magnetic flux density in both the inner and outer layers, a higher sinusoidal waveform, and lower non-working harmonic content, thus improving the torque density of the magnetic gear. Using finite element software, the magnetic flux density of the inner and outer air gaps and the torque of the inner and outer rotors are calculated and compared with traditional magnetic gears. The improved magnetic gear provided by this invention shows significantly improved electromagnetic performance and is suitable for transmission devices used in high-voltage disconnecting switch operating mechanisms.

[0028] 3. The high-performance magnetic gear transmission device for the operating mechanism of the disconnect switch provided by the present invention uses a magnetic block with coded teeth for the modulation ring, which can better modulate the inner and outer air gaps, increase the working harmonics, reduce the non-working harmonics, and thus significantly reduce torque pulsation. Attached Figure Description

[0029] Figure 1A multi-objective optimization flowchart provided for the implementation of this invention;

[0030] Figure 2 A schematic diagram of a high-performance magnetic gear transmission device for a disconnector operating mechanism provided for the implementation of this invention;

[0031] Figure 3 A schematic diagram of the high-voltage disconnector operating mechanism provided for the implementation of this invention;

[0032] Figure 4 A schematic diagram of the encoding and modulation process of the magnetic block with encoded teeth provided for the implementation of the present invention;

[0033] Figure 5 Optimization parameters for the magnetic gear model provided for the implementation of this invention;

[0034] Figure 6 Comprehensive sensitivity analysis results provided for the implementation of this invention;

[0035] Figure 7 The response surface plots of variable parameters h1 and h2 to the optimization objective provided for the implementation of this invention;

[0036] Figure 8 The optimization results of the multi-objective genetic algorithm provided for the implementation of this invention;

[0037] Figure 9 A comparison diagram of the radial magnetic flux density waveform of the inner air gap provided for the implementation of this invention;

[0038] Figure 10 A comparison diagram of radial harmonic amplitudes in the inner air gap provided for the implementation of this invention;

[0039] Figure 11 A comparison diagram of the radial magnetic flux density waveform of the outer air gap provided for the implementation of this invention;

[0040] Figure 12 A comparison diagram of radial harmonic amplitudes in the outer air gap provided for the implementation of this invention;

[0041] Figure 13 A torque waveform comparison diagram provided for the implementation of this invention. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0044] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application; as used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise; furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0045] The present invention provides a high-performance magnetic gear transmission device for a disconnector operating mechanism, such as... Figure 1-13 As shown. From the inside out, it includes: an inner rotor yoke 1, an inner rotor permanent magnet 2, a modulation ring 4 with coded teeth, an outer rotor permanent magnet 6, and an outer rotor yoke 7. An outer air gap 3 exists between the inner rotor and the modulation ring, and an inner air gap 5 exists between the modulation ring and the outer rotor; the outer rotor includes the outer rotor yoke 1 and the outer rotor permanent magnet 2; the inner rotor permanent magnet 6 is surface-mounted on the inner rotor yoke 7; both the inner rotor permanent magnet 2 and the outer rotor permanent magnet use a bread-shaped magnetization method, which can effectively reduce torque pulsation. Figure 3 The diagram shows the operating mechanism of a high-voltage disconnector. The operating mechanism mainly consists of a DC motor, a high-performance magnetic gear, an interphase rotating shaft, a crank arm, a contact spring, an insulating pull rod, a triangular crank arm, a stationary contact, and a moving contact. The inner rotor of the high-performance magnetic gear is connected to the output shaft of the DC motor, and the outer rotor is connected to the interphase rotating shaft. The high-performance magnetic gear transmission device replaces the traditional worm gear or lead screw and nut reduction device, enabling the high-voltage disconnector to reliably open and close.

[0046] High-performance magnetic gears mainly consist of an inner rotor, a modulation ring, and an outer rotor. The magnetic fields generated by the permanent magnets of the inner and outer rotors are modulated by the modulation ring, producing harmonic components in the air gap magnetic field. The working harmonics are used to transmit torque, while the non-working harmonics create torque pulsations. The expressions for the spatial harmonic orders generated by the inner and outer air gaps are as follows:

[0047] p m,k =|kN+mp (1)

[0049] In the formula, k = 0, ±1, ±2, ..., ∞, m = 1, 3, 5, ..., ∞, and N is the number of adjusting magnetic blocks. The number of pole pairs P of the external rotor permanent magnet 2 is... out And the number of pole pairs P of the inner rotor permanent magnet 6 in The following relationship must be satisfied: N = P out +P in The harmonic components in the air gap have specific pole pair numbers and rotational speeds. The angular velocities of the harmonic components in the inner and outer air gaps are expressed as:

[0050]

[0051] In the formula, Ω m,k Ω represents the angular velocity of the spatial harmonic components. r Ω represents the angular velocity of the inner and outer rotors. s To adjust the angular velocity of the magnetic ring.

[0052] The modulation ring of the high-performance magnetic gear transmission device for the operating mechanism of the disconnector switch proposed in this invention employs a magnetic adjustment block with coded teeth. The coded teeth not only conform to a unique shape similar to the coded signal, but also reflect the special relationship between the magnetic permeability harmonics and the magnetic adjustment block with coded teeth. Encoding, originally from computer science, is the process of converting information from one form or format to another. For example, characters, numbers, or other objects can be converted into specific electrical pulse signals in a predetermined manner, such that the electrical pulse signals contain specific information; numbers are encoded into electrical pulse signals. Similarly, specific magnetic permeability harmonics are also important information determining machine performance. The magnetic adjustment block with coded teeth is a specific structure that can generate these harmonics. Encoding the magnetic permeability harmonics into the magnetic adjustment block with coded teeth better modulates the harmonic content in the inner and outer air gaps. The encoding modulation process of the magnetic adjustment block with coded teeth is as follows: Figure 4 As shown.

[0053] After selecting the optimization objective, it is also crucial to choose appropriate design variables and evaluate their impact on each objective. Considering the structural dimensional constraints of the improved magnetic gear, its main optimization variable parameters are as follows: Figure 5 As shown. a i It is the eccentricity of the inner rotor permanent magnet, a h The angle of the adjusting magnetic block is h, and the eccentric height of the outer rotor permanent magnet is h. w The heights of the encoder teeth of the magnetic block are h1, h2, h3, h4, h5, and h6, respectively. The optimization range of the variable parameters is shown in Table 1.

[0054] Table 1 Optimization range of variable parameters

[0055]

[0056]

[0057] To better illustrate the impact of the proposed coded tooth tuning block variable parameters on the optimization objective, a comprehensive sensitivity analysis of the variable parameters of the proposed model is conducted, introducing a comprehensive sensitivity S(x) i The comprehensive sensitivity can integrate the influence of variable parameters on each objective function. Based on the opening and closing process of the high-performance magnetic gear transmission device used in disconnecting switches, reasonable weighting coefficients are determined, and the comprehensive sensitivity of a single variable parameter to the three optimization objective functions can be obtained. Its calculation expression is as follows:

[0058]

[0059] In the formula, G Te It is the sensitivity coefficient of the external rotor torque, G b1 It is the sensitivity coefficient for external rotor torque pulsation; G b2 It is the sensitivity coefficient for internal rotor torque ripple. In addition, ω1, ω2 and ω3 are the weighting coefficients for external rotor torque, external rotor torque ripple and internal rotor torque ripple, respectively, and satisfy ω1+ω2+ω3=1.

[0060] The results of the comprehensive sensitivity analysis are as follows: Figure 6 As shown in the figure, it can be seen that the sensitivity factors of the encoding tooth heights h1, h2, h3, h4, h5, and h6 of the adjusting magnetic block on the torque pulsation of both the inner and outer rotors are all greater than 0.2, indicating that the encoding teeth of the adjusting magnetic block have a significant effect on torque pulsation. Similarly, the eccentricity arc a of the inner rotor permanent magnet... i , Adjusting the angle a of the magnetic block h and the eccentric height h of the outer rotor permanent magnet w The sensitivity factor to torque is greater than 0.2, indicating that the angle of the adjusting block and the eccentric height of the outer rotor permanent magnet have a significant impact on the torque.

[0061] In engineering optimization design, polynomial approximation models are mainly used to describe the functional relationship between design variables and response objectives. To clearly and quickly obtain the changing patterns between the response objective and design variables and to calculate the data, based on the response surface methodology, the response model expression for the magnetic gear is as follows:

[0062]

[0063] In the formula, y(x) is the predicted value of output torque or torque ripple, n is the number of variable parameters, α is the regression coefficient, x is the variable parameter, and δ is the statistical error value.

[0064] This invention uses two design variables, h1 and h2, as an example to plot the response surface diagrams of variable parameters h1 and h2 to the optimization objective. The results are as follows: Figure 7 As shown in the figure, it can be seen that when h1 is 1.7mm and h2 is 1.2mm, the torque pulsation b1 of the outer rotor is minimized; when h1 is 1.4mm and h2 is 1.1mm, the torque pulsation b2 of the inner rotor is minimized. It is difficult to accurately determine the optimal design values ​​of design variables through univariate analysis; further reasonable trade-offs are needed among multiple optimization objectives.

[0065] To address the optimization problem involving multiple objectives, this invention combines the multi-objective genetic algorithm NSGA-II with the finite element method (FEM) to obtain the optimal design points for both high output torque and low torque ripple targets. The electromagnetic performance of each design point in the genetic algorithm is calculated using the FEM, meaning the FEM results are simultaneously passed to the optimization program, thus improving the accuracy of the optimization results. The final optimization result obtained using the NSGA-II algorithm is shown below. Figure 8 As shown in the figure, the sphere point is the feasible point for the optimized design of the model, and the square point is the optimal design point. The output torque of this point is the largest, and the torque pulsation of the outer rotor and the torque pulsation of the inner rotor are both the smallest, which is consistent with the optimization scheme of the design model in this paper. The specific parameters of its multi-objective function optimization results are shown in Table 2.

[0066] Table 2 Optimization results of variable parameters

[0067]

[0068] Figure 9 The radial magnetic flux density waveforms of the inner air gap of the improved and traditional magnetic gears are presented. It can be seen that by modulating with a magnetizing block with coded teeth, improving the shape of the inner and outer rotor permanent magnets, and optimizing with a multi-objective genetic algorithm, the amplitude of the radial air gap magnetic flux density increases, and the waveform is closer to a sine wave.

[0069] Figure 10 The harmonic spectrum of the magnetic flux density in the inner air gap is presented. According to the magnetic field modulation theory, the 4th, 17th, 25th, 38th, and 46th harmonic components are the operating harmonics. The operating harmonic components of the improved magnetic gear are larger than those of the traditional type, which is beneficial for torque transmission in the inner air gap. In addition, compared with the traditional magnetic gear, the non-operating harmonic components of the 12th, 20th, 28th, 33rd, 36th, and 41st orders of the improved magnetic gear are significantly suppressed. The reduction of these non-operating harmonics helps to reduce the torque pulsation of the improved magnetic gear.

[0070] like Figure 11 The waveforms of the radial magnetic flux density in the outer air gap of the improved and conventional magnetic gears are shown. The waveform amplitude of the improved magnetic gear is slightly larger than that of the conventional type. Figure 12 The harmonic spectrum of the outer air gap magnetic flux density is given. As can be seen from the figure, under the combined effect of bread-shaped magnetization of the inner and outer rotor permanent magnets and the magnetic adjustment block with adjusting teeth, the amplitude of the working harmonics of the improved magnetic gear is larger than that of the traditional magnetic gear, especially the amplitude of the 17th working harmonic, which helps to increase the output torque of the improved magnetic gear.

[0071] The modulation ring with coded teeth remains stationary, while the high-speed inner rotor and the low-speed outer rotor rotate in opposite directions at 170 r / min and 40 r / min, respectively. The torque waveforms of the inner and outer rotors are as follows: Figure 13As shown in the figure, the improved magnetic gear has a higher output torque than the traditional magnetic gear. The output torque of the outer rotor of the improved magnetic gear is 249.98 Nm, while the output torque of the traditional magnetic gear is 246.53 Nm, an increase of 1.4%. b is defined as the torque ripple coefficient, representing torque ripple, and the specific formula is as follows:

[0072]

[0073] In the formula, T max For maximum output torque, T min For minimum output torque, T ave This represents the average output torque.

[0074] Table 3 lists the torque and torque ripple coefficient of the improved magnetic gear and the traditional magnetic gear, respectively. As can be seen from Table 3, the torque ripple coefficient of the inner rotor decreased from 6.91% to 0.36%, and the torque ripple coefficient of the outer rotor decreased from 3.89% to 0.77%. This is because the improved magnetic gear uses a coded-tooth adjusting block to modulate the inner and outer air gaps, which not only improves the air gap magnetic field, making it more sinusoidal, but also suppresses some higher-order non-working harmonics, thereby reducing torque ripple and improving the stability of the magnetic gear operation.

[0075] Table 3 Torque and Torque Pulse

[0076]

[0077] To investigate the advantages of the high-performance magnetic gear transmission device provided by this invention in improving torque density and reducing torque pulsation, the volume, torque density, and permanent magnet mass of the improved and traditional magnetic gears were calculated and compared. The results are listed in Table 4. The improved magnetic gear uses less permanent magnet, and its torque density is reduced from 141.19 kNm / m. 3 Increased to 143.17 kNm / m 3 .

[0078] Table 4. Quantitative Comparison of Two Types of Magnetic Gears

[0079]

Claims

1. A high-performance magnetic gear transmission device for a disconnector operating mechanism, characterized by, From outside to inside, it includes outer rotor yoke, outer rotor permanent magnet, modulation ring with coding tooth, inner rotor permanent magnet and inner rotor yoke; there are air gaps between outer rotor yoke and modulation ring with coding tooth and between inner rotor yoke and modulation ring with coding tooth; the modulation ring with coding tooth is specifically a modulation block with coding tooth for magnetic modulation, and the outer rotor permanent magnet and the inner rotor permanent magnet are both bread-type magnetization; The improved magnetic gear is optimized by using the optimization method combining response surface method and multi-objective genetic algorithm, including the following steps: Step 1: determining optimization target, optimization variable and constraint condition; Step 2: using response surface method and multi-objective genetic algorithm to obtain optimal design point respectively; Step 3: comparing and analyzing the electromagnetic performance of the optimized improved magnetic gear and the traditional magnetic gear; The space harmonic number expression of the inner and outer air gaps is as follows: p m,k = |kN+mp| (1) where k = 0, ±1, ±2, …, ∞, m = 1, 3, 5, …, ∞, N is the number of flux modulation blocks; pole pair number P of the outer rotor permanent magnet out and pole pair number P of the inner rotor permanent magnet in satisfies the following relationship: N = P out + P in ; the harmonic components in the air gap have specific pole pair numbers and rotational speeds, and the angular velocities of the harmonic components in the inner and outer air gaps are represented as: where Ω m,k is the angular velocity of the spatial harmonic component r is the angular velocity of the inner and outer rotor s is the angular velocity of the field regulating ring The comprehensive sensitivity S(x i ) is introduced, which comprehensively reflects the influence of the variable parameters on the objective functions. According to the high-performance magnetic gear transmission device used for the opening and closing process of the disconnector, reasonable weight coefficients are determined, and the comprehensive sensitivity of the single variable parameter to the three optimization objective functions is obtained. The calculation expression is as follows: wherein G Te is a sensitivity coefficient of the outer rotor torque, G b1 is a sensitivity coefficient of the outer rotor torque pulsation; G b2 is a sensitivity coefficient of the inner rotor torque pulsation, ω1, ω2, and ω3 are weight coefficients of the outer rotor torque, the outer rotor torque pulsation, and the inner rotor torque pulsation, respectively, and satisfy ω1+ω2+ω3=1; Based on the model theory of response surface method, the response model expression of the magnetic gear is as follows: In the formula, y(x) is the predicted value of output torque or torque ripple, n is the number of variable parameters, α is the regression coefficient, x is the variable parameter, and δ is the statistical error value; The multi-objective genetic algorithm NSGA-II is combined with the finite element method to obtain the optimal design point of high output torque and low torque ripple, and the electromagnetic performance of each design point in the genetic algorithm is calculated by the finite element method; the modulation ring with coding tooth remains stationary, and the high-speed inner rotor and the low-speed outer rotor rotate reversely at 170 r / min and 40 r / min respectively; b is defined as torque ripple coefficient, which represents torque ripple, and the specific formula is as follows: where T max is the maximum output torque, T min is the minimum output torque, T ave is the average output torque.

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