Composite winding for double-speed asynchronous motor

Abstract

The invention discloses a composite winding for a double-speed asynchronous motor, relates to the technical field of motor design and manufacturing, and aims to solve the problem that specific harmonic weakening and fundamental wave strengthening are difficult to realize on the premise of not increasing the material consumption in the conventional double-speed asynchronous motor. According to the scheme, a stator core is of a lamination structure, and an upper layer and a lower layer are wound in a groove in the radial direction; the 10p stator coil I and the 10p stator coil II are symmetrically arranged in space; the number of turns of the 12p stator coils is equal, and the 12p stator coils and the 10p coil layers are distributed in different layers; a 2.0 drawing filler strip, a 3.0 drawing filler strip and a platinum thermal resistor are arranged at the end part of the stator, so that mechanical support and temperature rise monitoring are realized; the winding adopts a double-Y-shaped loop structure, and 10-pole and 12-pole mode switching is realized through external switching. The structure can effectively reduce harmonic distortion and additional loss, improve efficiency and reduce temperature rise, and is suitable for design and manufacturing of a high-efficiency energy-saving double-speed asynchronous motor.

Description

Technical Field

[0001] This invention relates to the field of motor design and manufacturing technology, and in particular to a composite winding structure design for a dual-speed asynchronous motor. Background Technology

[0002] In dual-speed asynchronous motors, a common practice is to use traditional distributed windings with equal number of turns, equal pitch, and 60° phase bands to accommodate the operation of both pole pairs. However, the magnetomotive force of such windings generally contains strong odd-order space harmonics (especially the 5th and 7th). These harmonics induce harmonic currents and harmonic torques on the rotor side, resulting in additional losses, reduced efficiency, increased temperature rise, and vibration and noise problems, which have a long-term impact on the overall lifespan and performance stability of the motor.

[0003] In order to achieve "acceptable" performance at two speeds, engineers often improve magnetic flux density and losses by lengthening the iron core or enlarging the slot shape. However, this approach trades performance for increased effective material usage, which not only significantly increases costs but also fails to suppress the source of space harmonics and additional losses from a mechanistic perspective. Therefore, the improvement in efficiency and temperature rise is limited, resulting in poor cost-effectiveness.

[0004] Another common approach is to simply shorten the pitch to weaken specific harmonics (such as the 5th and 7th harmonics). However, shortening the pitch directly reduces the number of effective series conductors per phase and the fundamental magnetomotive force, thus sacrificing output and efficiency. In dual-speed scenarios, this side effect creates a sharper trade-off between the two pole pair numbers, resulting in one condition improving while the other deteriorates, making it difficult to achieve overall optimization.

[0005] A deeper pain point lies in the fact that traditional equal-turn symmetrical windings struggle to achieve selective harmonic suppression and fundamental frequency enhancement while simultaneously satisfying slot fill factor and conductor number constraints. There is a lack of a design method for dual-speed motors that can quantitatively determine the turns ratio of each coil to eliminate or weaken a specific harmonic under given slot-pole configurations. As a result, designers often have to weigh experience against trial and error, unable to achieve controllable and reproducible suppression of specific harmonics, and struggling to achieve consistent low harmonic and high efficiency performance across two pole pair numbers (e.g., 10 poles / 12 poles). The corresponding reality is that in typical dual-speed motor original winding schemes, the 5th and 7th harmonics are relatively high, directly increasing additional losses, temperature rise, and noise (e.g., the 5th harmonic coefficient of the original 10-pole scheme in this article is 0.13985, and the 7th harmonic is 0.06066, which is considered high), reflecting the inherent deficiencies of traditional windings in dual-speed synergistic optimization.

[0006] Furthermore, from the perspective of manufacturing economics and energy conservation, the existing dilemma is particularly prominent: either rely on the cumbersome method of "adding materials" to meet performance targets by increasing the investment in copper and silicon steel; or rely on the hard suppression of harmonics by "reducing pitch," but at the cost of output and efficiency. Neither approach can simultaneously take into account material costs, fundamental magnetomotive force, specific harmonic suppression, dual-speed consistency, and a replicable design process.

[0007] In summary, existing technologies have the drawback of failing to achieve selective weakening of specific harmonics under two pole pair numbers and simultaneous strengthening of the fundamental wave without increasing the effective material usage and ensuring the effective number of series conductors and slot fill factor, thereby reducing additional losses, improving efficiency, voltage drop and temperature rise, and vibration and noise reduction, and possessing a reproducible quantitative winding design method. Summary of the Invention

[0008] To address the shortcomings of existing technologies, which struggle to selectively weaken specific harmonics and simultaneously strengthen the fundamental wave under two pole pair numbers without increasing effective material usage or ensuring the effective number of series conductors and slot fill factor, thereby reducing additional losses, improving efficiency, voltage drop and temperature rise, and reducing vibration and noise while possessing a reproducible quantitative winding design method, the present invention provides the following technical solution: A composite winding for a dual-speed asynchronous motor, comprising: The stator core has a laminated structure, which is arranged in two layers in the radial direction within the slot, and the slot opening is fixed by slot wedges; The 10p stator coil one, the 10p stator coil two, and the 12p stator coil are respectively embedded in the slots of the stator core, and the 10p stator coil one and the 10p stator coil two are arranged symmetrically in space. The 12p stator coil has the same number of turns and is not on the same layer as the 10p stator coil one and the 10p stator coil two; 2.0 and 3.0 pull-out pads are installed at the ends of the stator core to support and position the coil lead-out end and the bent section; Platinum resistance thermometers are also embedded at the ends of the stator core to detect the temperature rise of the windings during operation; The three-phase terminals of 10p stator coil one and 10p stator coil two are connected in a Y-shape, and the 12p stator coil is connected in a Y-shape. The neutral point and phase terminal of the two Y-shaped circuits are respectively led to the terminal block.

[0009] Furthermore, a preferred embodiment is provided in which polyester glass fiber rope is wound around the ends of the 10p stator coil one, the 10p stator coil two, and the 12p stator coil for end binding and overall fixation.

[0010] Furthermore, a preferred embodiment is provided in which a platinum resistance thermometer is connected to a temperature detection unit via leads to monitor the winding temperature rise in real time, thereby achieving stable operation control of the composite winding of a dual-speed asynchronous motor.

[0011] Furthermore, a preferred embodiment is provided in which the stator core has a laminated structure and a slot wedge is provided at the slot opening to limit the space inside the slot and fix the winding position.

[0012] Furthermore, a preferred embodiment is provided in which the turns ratios of both the 10p stator coil one and the 10p stator coil two are 6 / 9 / 6, forming a composite winding structure.

[0013] Furthermore, a preferred embodiment is provided in which the 2.0 pull-out pad and the 3.0 pull-out pad are respectively arranged at the two ends of the stator core to support and traction fix the coil lead-out end and the bent part.

[0014] Based on the same inventive concept, this invention also provides a control method for a composite winding of a dual-speed asynchronous motor, implemented based on the aforementioned winding, comprising: The steps for receiving platinum resistance thermometer signals and calculating the temperature rise of the 10p stator coil one, 10p stator coil two, and 12p stator coils; When the temperature rise exceeds the threshold, an alarm will be triggered or a shutdown protection procedure will be executed. The steps to determine whether the device is in 10-pole or 12-pole operating mode based on the status of the external switching device; The steps for selecting the corresponding Y-shaped circuit of 10p stator coil one, 10p stator coil two or 12p stator coil for on / off control; The steps involve monitoring the current balance and adjusting the excitation phase to maintain a stable magnetomotive force.

[0015] Based on the same inventive concept, the present invention also provides a computer storage medium for storing a computer program, wherein when the computer program is read by a computer, the computer executes the method described thereon.

[0016] Based on the same inventive concept, the present invention also provides a computer, including a processor and a storage medium, wherein when the processor reads a computer program stored in the storage medium, the computer executes the method described thereon.

[0017] Based on the same inventive concept, the present invention also provides a computer program product, which, when executed, implements the method described.

[0018] Compared with the prior art, the advantages of the technical solution provided by the present invention are as follows: This solution introduces a composite winding structure into a dual-speed asynchronous motor, using coil arrangements with unequal turns and pitches to weaken specific high-order harmonic magnetomotive forces (MTFs). By employing a 6-9-6 turns ratio combination in the 10-pole winding, the harmonic MMFs generated by coils in different slots cancel each other out, thereby significantly reducing the 5th and 7th harmonic components. Compared to existing solutions using equal-turn, equal-pitch windings, this design reduces harmonic distortion while maintaining the fundamental MMF strength, improves the air gap magnetic field distribution, and results in smoother motor output torque and significantly improved efficiency.

[0019] This design, by shortening the pitch to 7 and optimizing the coil arrangement, effectively reduces high-order harmonics while maintaining high slot fill factor and conductor utilization. Compared to traditional solutions that improve performance by increasing core length or enlarging slot size, this design reduces additional losses caused by harmonics without increasing material usage, achieving energy saving and consumption reduction. The overall harmonic distortion rate of the motor is reduced by approximately 5%–6%, and copper wire usage is reduced by approximately 10%, achieving a balance between performance improvement and material conservation.

[0020] This scheme utilizes a composite design method based on harmonic winding coefficient calculation to perform harmonic optimization calculations for windings with different pole pair numbers. This method achieves a performance balance for the dual-speed motor under two operating conditions by programmatically solving for the harmonic attenuation effect under different turns ratio distributions. Compared with traditional empirical winding design methods, this method is quantifiable and repeatable, ensuring uniform magnetic field distribution and minimal losses at different speeds, thus improving the electromagnetic performance and reliability of the dual-speed motor.

[0021] This design utilizes a composite winding structure to eliminate or significantly weaken high-order harmonic magnetomotive forces, thereby reducing additional losses and copper losses during motor operation and resulting in a significant decrease in temperature rise. Unlike existing methods that enhance heat dissipation through cooling systems, this design suppresses heat sources at the electromagnetic origin, reducing thermal stress and energy waste, and achieving higher energy efficiency and more stable operating performance.

[0022] This solution reduces vibration and noise caused by harmonic torque by improving the symmetry of the magnetomotive force waveform. Traditional motors often experience torque pulsation and noise problems due to the presence of high-order harmonics, while the composite winding can achieve steady-state operation under the premise of smoothing the magnetomotive force curve, thereby simultaneously reducing mechanical vibration and electromagnetic noise, and improving the overall stability and service life of the motor.

[0023] This design breaks away from the traditional high-efficiency motor approach that relies on increasing the amount of usable material. It employs a design method based on the harmonic compensation principle of composite windings, achieving a balance between energy conservation, environmental protection, and manufacturing costs. Compared to existing technologies, this solution not only reduces material costs but also significantly improves efficiency and power density, aligning with the development trend of high-efficiency and energy-saving motors. It possesses significant promotional value and a competitive advantage in the industry.

[0024] It is suitable for the design and manufacturing of dual-speed asynchronous motors that require efficient operation at different speeds. Attached Figure Description

[0025] Figure 1 A schematic diagram of the stator core; Figure 2 for Figure 1 A sectional view; Figure 3 This is a schematic diagram of the 10P winding coefficient.

[0026] Among them, 1 is the slot wedge, 2 is the 2.0 pull-out pad, 3 is the 12p stator coil, 4 is the 3.0 pull-out pad, 5 is the platinum resistance thermometer, 6 is the 10p stator coil one, 7 is the 10p stator coil two, 8 is the polyester glass fiber rope, and 9 is the stator core. Detailed Implementation

[0027] To make the advantages and benefits of the technical solution provided by the present invention clearer, the technical solution provided by the present invention will now be described in further detail with reference to the accompanying drawings, specifically: Implementation Method 1: This implementation method provides a composite winding for a dual-speed asynchronous motor, comprising: The stator core 9 has a laminated structure, which is arranged in two layers in the radial direction within the slot, and the slot opening is fixed by the slot wedge 1; The 10p stator coil 6, the 10p stator coil 7, and the 12p stator coil 3 are respectively embedded in the slots of the stator core 9. The 10p stator coil 6 and the 10p stator coil 7 are arranged symmetrically in space. The 12p stator coil 3 has the same number of turns, and is not on the same layer as the 10p stator coil 6 and the 10p stator coil 7. 2.0 pull-out pads 2 and 3.0 pull-out pads 4 are provided at the ends of the stator core 9 to support and position the coil lead-out end and the bent section; The stator core 9 is also equipped with a platinum resistance thermometer 5 at its end, which is used to detect the temperature rise of the winding during operation; The three-phase terminals of 10p stator coil 6 and 10p stator coil 7 are connected in a Y-shape, and 12p stator coil 3 is connected in a Y-shape. The neutral point and phase terminals of the two Y-shaped circuits are respectively led to the terminal blocks.

[0028] Polyester glass fiber rope 8 is wound around the ends of 10p stator coil 1 6, 10p stator coil 2 7 and 12p stator coil 3 for end binding and overall fixation.

[0029] The platinum resistance thermometer 5 is connected to the temperature detection unit via leads to monitor the winding temperature rise in real time, thereby enabling stable operation control of the composite winding of the dual-speed asynchronous motor.

[0030] The stator core 9 has a laminated structure, and a slot wedge 1 is provided at the slot opening to limit the space inside the slot and fix the winding position.

[0031] The turns ratios of both the 10p stator coil 6 and the 10p stator coil 7 are 6 / 9 / 6, forming a composite winding structure.

[0032] 2.0 Pull-out pad 2 and 3.0 pull-out pad 4 are respectively arranged at the two ends of the stator core 9 to support and traction fix the coil lead-out end and the bent part.

[0033] A control method for a composite winding of a dual-speed asynchronous motor is also provided, based on the aforementioned winding, comprising: The steps for receiving the signal from the platinum resistance thermometer 5 and calculating the temperature rise of the 10p stator coil 6, the 10p stator coil 7, and the 12p stator coil 3; When the temperature rise exceeds the threshold, an alarm will be triggered or a shutdown protection procedure will be executed. The steps to determine whether the device is in 10-pole or 12-pole operating mode based on the status of the external switching device; The steps for selecting the corresponding Y-shaped circuit of 10p stator coil 6, 10p stator coil 7 or 12p stator coil 3 to perform on / off control; The steps involve monitoring the current balance and adjusting the excitation phase to maintain a stable magnetomotive force.

[0034] A computer storage medium is also provided for storing a computer program, which, when read by the computer, executes the method.

[0035] A computer is also provided, including a processor and a storage medium, wherein the computer executes the method when the processor reads a computer program stored in the storage medium.

[0036] A computer program product is also provided, which, when executed, implements the method described.

[0037] Implementation Method Two: This implementation method is a further detailed description of the technical solution provided in Implementation Method One, specifically: The embodiments provided by this invention are geared towards dual-speed asynchronous motors, constructing a composite winding and assembly structure consisting of a stator core 9, a 10p stator coil one 6, a 10p stator coil two 7, a 12p stator coil 3, a slot wedge 1, a 2.0mm pull-out pad 2, a 3.0mm pull-out pad 4, a platinum resistance thermometer 5, and a polyester glass fiber rope 8. Under both 10-pole and 12-pole operating conditions, through a composite design of turns ratio and pitch, selective attenuation of specific high-order harmonics is achieved while maintaining the fundamental magnetomotive force, thereby reducing additional losses and temperature rise, while ensuring slot fill factor and the effective number of series conductors. Specifically: Implementation steps: Step S1: Determine electromagnetic and structural input parameters Obtain the slot-pole fit, number of parallel circuits, and winding layer type of the motor to form the basic input for subsequent winding design calculations.

[0038] In detail: The number of slots in stator core 9 and the combination of two pole pair numbers are selected. For example, Z1 is 90, Z2 is 110, and the number of pole pairs is 10 / 12, using a double-layer lap winding structure. The number of slots per pole per phase of the coil is 3 in the 10-pole configuration and 2.5 in the 12-pole configuration. The number of parallel connections in the stator is determined to be 1 Y-connection. The core length is 940 mm, and the original number of conductors per slot is 14 and 20 under the two pole pair numbers, respectively, serving as constraints for subsequent conductor utilization and slot fill factor. This step outputs the determination result of the "slot-pole combination and parallel connection method," which serves as the input for S2.

[0039] Step S2: Set the harmonic suppression target and solve for the winding turns ratio. Under a given slot-pole configuration, determine the harmonic order that needs to be reduced and calculate the coil turns ratio and pitch.

[0040] In detail: For the 5th and 7th space harmonics, which commonly have a significant impact on operation, the winding coefficient is set to be significantly reduced or close to zero; in the 10-pole state, the turns ratio of each coil group is determined to be 6-9-6 through programmed solution, and the coil pitch is adjusted from 8 to 7; in the 12-pole state, the 12p stator coil 3 is determined to have equal turns distribution, and the wire gauge is optimized accordingly to maintain the fundamental magnetomotive force and conductor utilization. This step outputs the design data of "10-pole turns ratio 6-9-6 and pitch 7, 12-pole equal turns and wire gauge matching", which is used as the input of S3.

[0041] Step S3: Establish slot-coil allocation table and winding sequence Map the turns ratio and pitch data of S2 to specific slots to determine the upper and lower layer relationships and phase sequence of the double-layer winding.

[0042] In detail: In each of the three slots of each pole and each phase of the stator core 9, 10p stator coil 1 (6 turns) and 10p stator coil 2 (7 turns) are arranged in the order of 6 turns, 9 turns, and 6 turns, so that they form a symmetrical unequal turn arrangement in space; in the 12-pole state, 12p stator coil 3 is mapped to the corresponding slot according to the principle of equal turns and equal spacing. A slot-coil allocation table containing phase, layer, pitch, span, and lead-out terminal number is formed, and the phase sequence consistency is checked. This step outputs the "slot-coil allocation table and winding sequence" as the input of S4.

[0043] Step S4: Preparation of stator core insulation system and pre-assembly of sensing elements An in-slot insulation and end positioning system is constructed on the stator core 9, and temperature monitoring elements are pre-installed.

[0044] In detail: Slot insulation is laid in each slot of the stator core 9. Slot wedges 1 are assembled at the slot openings according to the allocation table to define the coil positions. 2.0 pull-out pads 2 and 3.0 pull-out pads 4 are set at the ends and key bends to form a mechanical base for lead-out and traction protection. Platinum resistance thermometers 5 are embedded at appropriate positions at the ends as winding temperature rise monitoring elements, and the leads of the platinum resistance thermometers 5 are reserved to the terminal area. This step outputs "Stator core 9 assembly with winding conditions", which serves as the input for S5. In the figure, 1 is slot wedge 1, 2 is 2.0 pull-out pad 2, 3 is 12p stator coil 3, 4 is 3.0 pull-out pad 4, 5 is platinum resistance thermometer 5, 6 is 10p stator coil one 6, 7 is 10p stator coil two 7, 8 is polyester glass fiber rope 8, and 9 is stator core 9.

[0045] Step S5: Coil forming and winding Complete the forming and winding of 10p stator coil 6, 10p stator coil 7 and 12p stator coil 3 according to the allocation table.

[0046] In detail: First, 10p stator coil one (6) and 10p stator coil two (7) are formed on the winding fixture, followed by the formation of 12p stator coil three. According to the hierarchical sequence of S3, 10p stator coil one (6), 10p stator coil two (7), and 12p stator coil three are sequentially embedded into the corresponding slots of the stator core 9. At each slot, the pitch and span are checked to ensure the accuracy of the 6-9-6 turns ratio and equal turns distribution, and the pre-reserved leads at the ends naturally transition to the 2.0 pull-out pads 2 and 3.0 pull-out pads 4. This step outputs "Completed winding stator assembly," which serves as the input for S6.

[0047] Step S6: End binding, positioning and mechanical fixation The end coils are bound and reinforced as a whole to form a stable geometric shape.

[0048] In detail: Polyester glass fiber rope 8 is used to bind the ends of 10p stator coil 6, 10p stator coil 7, and 12p stator coil 3 in a circumferential and cross-linked manner. This, along with 2.0mm pull-out pads 2 and 3.0mm pull-out pads 4, establishes mechanical buffering at the bends and provides traction fixation for the lead wires. The tightness of the slot wedge 1 and the gap at the coil ends are checked to ensure sufficient electrical clearance and mechanical strength during operation. This step outputs "Reinforced Stator Winding End Structure," which serves as the input for S7.

[0049] Step S7: Circuit connection and terminal lead-out The electrical connection of the windings and the lead-out of external terminals are completed to form a circuit topology for dual-speed operation.

[0050] In detail: The 10p stator coil 6 and 10p stator coil 7 are connected in parallel at their respective ends to form a Y-shape, and the 12p stator coil 3 is also connected in a Y-shape according to its phase. The three-phase terminals and neutral point of the 10-pole and 12-pole circuits are led to the terminal blocks for easy connection to an external switching device to select 10-pole or 12-pole operation. The leads at both ends of the platinum resistance thermometer 5 are connected to the temperature measurement terminal for subsequent temperature rise monitoring. The number of parallel stator circuits is maintained at 1 to ensure symmetry under both pole pair numbers. This step outputs "Electrical connection status with power-on conditions," which serves as the input to S8.

[0051] Step S8: Insulation treatment, impregnation curing and shaping The stator after winding is insulated and cured to improve dielectric and mechanical stability.

[0052] In detail: The entire stator assembly is subjected to vacuum pressure impregnation and cured under a specified temperature profile, so that the 10p stator coil 6, 10p stator coil 7, and 12p stator coil 3 form a solidified whole within the stator core 9. After curing, end shaping and secondary binding verification are performed to ensure that the slot wedge 1 is locked, the pull-out pad is in place, and the polyester glass fiber rope 8 has uniform tension. This step outputs "Stator assembly with completed curing and shaping," which serves as the input for S9.

[0053] Step S9: Routine Testing and Performance Verification The electrical parameters and harmonic parameters were verified based on the objectives to confirm the design effectiveness.

[0054] In detail: Under the 10-pole configuration, the winding coefficients and no-load harmonic voltages for common harmonic sequences are measured. The measured results should show a significant reduction in the 5th harmonic and near elimination of the 7th harmonic, with the overall harmonic distortion rate decreasing by approximately 5.8% compared to the original scheme, and copper wire usage reduced by approximately 10.1%. Under the 12-pole configuration, the overall harmonic distortion rate is verified to be approximately 5.1% lower than the original scheme, and copper wire usage reduced by approximately 5.6%. Simultaneously, the temperature rise is measured using a platinum resistance thermometer 5 to confirm the correlation between the reduction in additional losses and the reduction in temperature rise. This step outputs a "standardized result meeting the specifications."

[0055] In terms of structure: Mechanical structure and material composition: The stator core 9 adopts a laminated structure. The slot is arranged with slot insulation, 10p stator coil 1 6, 10p stator coil 2 7 and 12p stator coil 3 in a double-layered winding. The slot opening is locked by slot wedge 1. At the end, 2.0 pull-out pads 2 and 3.0 pull-out pads 4 are set at the bending and wire exit positions. The entire end is tied and fixed by polyester glass fiber rope 8. Platinum resistance thermometer 5 is embedded near the hot spot at the end and a lead wire is reserved to the terminal area, forming an assembly structure of "core - winding - end support - temperature measuring component".

[0056] Circuit topology and wiring construction: The 10p stator coil 6 and the 10p stator coil 7 are connected in parallel in phase and then connected in a Y-shape. The 12p stator coil 3 is also connected in a Y-shape. The two sets of Y-shaped circuits and the neutral point are respectively led to the terminal blocks. The external switching device can select 10-pole or 12-pole operation. The number of stator parallel circuits is 1 to ensure consistent phase current distribution and electromagnetic symmetry. The platinum resistance thermometer 5 is connected to the control and protection unit through the temperature measurement terminal to provide temperature rise monitoring signals.

[0057] In practical operation: In the 10-pole configuration, the fundamental magnetomotive force is strengthened by matching the 6-9-6 turns ratio and pitch 7 of the 10p stator coil 6 and 10p stator coil 7, the 5th harmonic is reduced to a significantly low level and the 7th harmonic is nearly eliminated, resulting in a significant decrease in the overall harmonic distortion rate. In the 12-pole configuration, the equal turns and wire gauge matching of the 12p stator coil 3 achieve synergistic optimization under the two pole pair numbers. Both configurations show a decrease in copper wire usage and a reduction in temperature rise, proving that the composite winding design achieves selective weakening and efficiency improvement of specific harmonics without increasing the effective material usage.

[0058] Implementation Method 3: This implementation method is described in detail with reference to the accompanying drawings. Specific embodiments are provided to further illustrate the technical solutions offered above. Specifically: In asynchronous motors, the regular 60° phase winding generates all odd-order harmonic magnetomotive forces except for multiples of 3. These harmonics induce harmonic currents at the rotor sides, producing harmonic torque and additional losses, affecting motor performance. To achieve good performance at both speeds, most dual-speed motors employ methods such as lengthening the core and enlarging the slots to increase effective material usage and reduce temperature rise. However, this results in significant cost waste and does not solve the key problem of high additional losses, while also significantly increasing motor cost.

[0059] The composite winding of a dual-speed asynchronous motor consists of two sets and one set of harmonic reduction windings. The two sets refer to the 10p coil having 6 turns and another having 9 turns; the one set refers to the 12p coil having the same number of turns. This winding can eliminate a large portion of harmonic magnetomotive force, improve motor performance, increase efficiency for motors with large additional losses, reduce temperature rise, and allow for smaller stator wire gauges or shorter cores to save effective raw materials.

[0060] Starting from the analysis of the magnetomotive force of q coils with unequal turns and pitches in the positive and negative phases, where q represents the number of slots per pole per phase of the coil, while obtaining the general expression form of the winding coefficient, a composite winding is designed under the condition of ensuring the slot fill factor as much as possible. The turns ratio of each coil when a certain harmonic is to be eliminated or weakened is calculated. Therefore, a new winding structure for a dual-speed asynchronous motor is developed to improve motor performance and achieve the purpose of energy saving and environmental protection.

[0061] The main performance parameters of the motor are shown in Table 1.

[0062]

[0063] The composite winding calculation and analysis of the YDKK900-10 / 12 high-voltage dual-speed motor (1250kW / 900kW) is performed. The motor parameters are: Z1=90, Z2=110, p=10 / 12, double-layer lap winding, q=3 / 2.5, where q represents the number of slots per pole per phase of the coil, 3 for 10p and 2.5 for 12p, the original number of conductors per slot z=14 / 20, the pitch y=8 / 7, the core length l=940, and the number of stator parallel circuits is 1 Y-connected.

[0064] According to preliminary calculations, reducing the motor pitch by one can lower the motor's 5th harmonic, but it also reduces the number of effective series conductors per phase, directly affecting the motor's performance parameters. This necessitates modifying the motor windings to design a composite winding.

[0065] To ensure that the effective number of series conductors is only slightly different from the original scheme and to meet the motor performance parameters, the number of coil turns needs to be increased. Using the calculation of harmonic winding coefficients and relevant parameters from the electromagnetic calculation sheet, a program is used to calculate the number of turns per coil group for a 10P motor as 6-9-6, i.e., three slots per pole per phase, with the three slots having 6 / 9 / 6 turns respectively. The pitch is changed to 7 for calculation. After analysis, the symmetrical unequal turn winding can improve motor performance, reduce additional losses, and save copper wire usage. The modified winding stator core has 9 turns. Figure 1 As shown, the 10P winding coefficient is compared to, for example Figure 3 As shown.

[0066] according to Figure 3 It can be seen that the 5th harmonic of the original 10P motor design is 0.13985, which is too high. After the modification, the 5th harmonic is reduced to below 0.06. The 7th harmonic of the original design is 0.06066. After the modification, the 7th harmonic coefficient is basically reduced to 0. The overall harmonic distortion rate is reduced by 5.8%, and the amount of copper used in the 10P coil is reduced by 10.1%.

[0067] By changing the coil pitch and stator wire gauge of the 12P winding, the overall harmonic distortion rate of the motor was reduced by 5.1%, and the amount of copper used in the 12P coil copper wire was reduced by 5.6%.

[0068] The dual-speed asynchronous motor adopts a new type of composite winding structure. This winding can eliminate a large part of the harmonic magnetomotive force, improve motor performance, reduce temperature rise and improve efficiency for motors with large additional losses, and is more energy-saving and environmentally friendly. It can save effective raw materials and improve economic benefits.

[0069] The above description of several specific embodiments further details the technical solution provided by the present invention in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the above-described specific embodiments are not intended to limit the present invention. Any reasonable modifications and improvements to the present invention, combinations of embodiments, and equivalent substitutions based on the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A compound winding for a two-speed asynchronous motor, characterized in that, The stator core is a laminated structure, and is arranged in two layers in the radial direction in the slot, and the slot opening is fixed by a slot wedge. 10p stator coil one, 10p stator coil two and 12p stator coil are embedded in the slot of the stator core, and 10p stator coil one and 10p stator coil two are arranged symmetrically in space. The number of turns of 12p stator coil is equal, and is not in the same layer as 10p stator coil one and 10p stator coil two. 2.0 drawing pad strips and 3.0 drawing pad strips are arranged at the end of the stator core, which are used to support and position the coil outlet end and the bending section. A platinum resistance is embedded at the end of the stator core, which is used to detect the operating temperature rise of the winding. The three-phase end points of 10p stator coil one and 10p stator coil two are connected in Y shape, and 12p stator coil is connected in Y shape, and the neutral points of the two Y-shaped loops are respectively led to the connection terminal. Polyester glass silk rope is wound on the end of 10p stator coil one, 10p stator coil two and 12p stator coil, which is used for end binding and overall fixation.

2. A compound winding for a two-speed asynchronous motor according to claim 1, characterized in that, The platinum resistance is connected to the temperature detection unit through the lead wire, which is used to monitor the winding temperature rise in real time and realize the stable operation control of the compound winding of the double-speed asynchronous motor.

3. A compound winding for a two-speed asynchronous motor according to claim 1, characterized in that, The stator core is a laminated structure, and a slot wedge is arranged at the slot opening to limit the space in the slot and fix the position of the winding.

4. A compound winding for a two-speed asynchronous motor according to claim 1, characterized in that, The turn ratio of 10p stator coil one and 10p stator coil two is 6 / 9 / 6, which constitutes a compound winding structure.

5. A compound winding for a two-speed asynchronous motor according to claim 1, characterized in that, 2.0 drawing pad strips and 3.0 drawing pad strips are arranged at the two ends of the stator core, which are used to support and pull the coil outlet end and the bending section.

6. A compound winding for a two-speed asynchronous motor according to claim 1, characterized in that, The winding implementation based on claim 1, comprising:

7. A control method for a compound winding of a two-speed asynchronous motor, characterized in that, receiving the platinum resistance signal and calculating the temperature rise of 10p stator coil one, 10p stator coil two and 12p stator coil; issuing an alarm or executing a shutdown protection when the temperature rise exceeds a threshold value; determining whether to be in 10-pole or 12-pole operation mode according to the state of the external switching device; selecting the Y-shaped loop of 10p stator coil one, 10p stator coil two or 12p stator coil for on-off control; monitoring current balance and adjusting excitation phase to maintain magnetic potential stability. When the computer program is read by the computer, the computer executes the method of claim 7.

8. Computer storage medium for storing a computer program, characterized in that When the processor reads the computer program stored in the storage medium, the computer executes the method of claim 7.

9. A computer comprising a processor and a storage medium, characterized in that When the computer program is executed, the method of claim 7 is implemented.

10. Computer program product as computer program, characterized in that ​

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