A rotor for a remote power supply starting induction motor and an optimization method thereof

Abstract

This invention discloses a rotor suitable for long-distance power supply starting induction motors and its optimization method. The rotor includes a rotor core with multiple convex slots. These slots include interconnected top-level slots and bottom-level slots. The bottom-level slots are located further away from the air gap than the top-level slots, meaning they are closer to the rotor core axis. The top-level slots are parallel slots. The width of the bottom-level slots gradually narrows from the side closer to the top-level slots towards the side farther away. This invention, by modifying the rotor slot structure, increases the starting torque and reduces the starting current, improving starting performance while ensuring minimal impact on the motor's overall operating performance. The invention has a simple structure, significantly increases starting torque and reduces starting current, and has wide applicability.

Description

Technical Field

[0001] This invention relates to the field of equipment technology related to motor production, and in particular to a rotor suitable for starting induction motors with power supply over long distances. Background Technology

[0002] Induction motors started over long distances suffer from several drawbacks due to the long power transmission lines. Firstly, this results in a significant voltage drop and a large current flow, increasing the risk of motor burnout during startup. Secondly, the voltage across the motor is often too low to achieve the required starting torque, preventing successful starting. Existing and widely used methods, such as... Figure 1 The pear-shaped slot structure shown has a very limited effect on improving starting performance; the existing convex rotor slot structure is rarely used in actual production because the top part is mostly a trapezoidal or inverted trapezoidal structure, which is complex in shape and makes it difficult to process with a die. Furthermore, since the rotor teeth corresponding to the top slot are parallel teeth, it cannot improve starting performance over a wide range. Summary of the Invention

[0003] This invention proposes a rotor suitable for remote power supply starting induction motors. Its purpose is to solve the problems existing in the background technology and improve the starting performance of remote power supply starting induction motors, that is, to reduce the starting current of the induction motor and increase the starting torque of the induction motor within a wider range, so that the induction motor can start and work normally.

[0004] The present invention proposes a rotor suitable for long-distance power supply starting induction motor, comprising a rotor core, wherein the rotor core has multiple convex slots, the convex slots including a top-level slot portion and a bottom-level slot portion that are interconnected, the bottom-level slot portion being farther away from the air gap relative to the top-level slot portion, that is, the bottom-level slot portion being closer to the axis of the rotor core relative to the top-level slot portion, the top-level slot portion being a parallel slot, and the slot width of the bottom-level slot portion gradually narrowing from the side closer to the top-level slot portion to the side farther away from the top-level slot portion.

[0005] Rotor teeth are formed between any two adjacent convex slots. Compared with existing parallel teeth, the rotor teeth of this application have the largest effective rotor slot area when consuming the same magnetic flux. When the slot depth is large, the lamination utilization area is larger, which can effectively reduce aluminum consumption and improve motor efficiency.

[0006] Preferably, the convex groove is a semi-open groove.

[0007] Preferably, the convex groove is an axial inclined groove.

[0008] Preferably, the depth of the top-level groove is less than the depth of the bottom-level groove.

[0009] Preferably, when the rotor is used in an induction motor with a power greater than or equal to 100kW, the groove depth of the convex groove is greater than 45mm; when the rotor is used in an induction motor with a power less than 100kW, the groove depth of the convex groove is less than 30mm. This convex groove, when the groove depth is larger, has a larger groove leakage resistance during startup and a smaller groove leakage resistance during operation compared to a parallel groove, thus simultaneously meeting the requirements for both startup and running performance.

[0010] Preferably, the width of the top-level groove is smaller than the bottom width of the bottom-level groove.

[0011] When the rotor convex slot of this application has a relatively large slot depth, its performance is significantly better than that of parallel teeth and parallel slots. The parameters that have a greater impact on the slot leakage reactance of the motor are the top slot depth, top slot width, bottom slot depth, and bottom width of the bottom slot portion. Among them, the top slot width and the bottom width of the convex slot have the main influence. By changing these parameters, the size of the slot leakage reactance can be changed, thereby adjusting the starting performance of the motor.

[0012] A rotor suitable for long-distance power supply starting induction motor and its optimization method, used to optimize the above-mentioned convex slot structure, includes the following steps:

[0013] S1: Establish a rotor model and match the rotor model with the stator to form a motor model;

[0014] S2: Perform finite element simulation on the motor model formed in S1, and obtain the effective value of the corresponding starting current by analyzing the stall current in the simulation results.

[0015] S3: The particle swarm optimization algorithm is used to optimize the groove depth hup and groove width bup of the top groove of the rotor convex groove, the groove depth hdown and bottom width bdown of the bottom groove as optimization factors, and the finite element optimization software is used for optimization calculation and analysis.

[0016] S4: Optimization factors for selecting motors to obtain minimum starting current and maximum starting torque.

[0017] The rotor and its optimization method for long-distance power supply starting induction motors proposed in this invention have the following effects: By changing the rotor slot structure, the starting torque of the motor is increased and the starting current is reduced, improving starting performance while ensuring that the motor's operating performance is basically unaffected, all while facilitating the machining of the rotor slots. This invention has a simple structure, significantly increases starting torque and reduces starting current, and has wide applicability.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a pear-shaped slot structure for a motor rotor, which is widely used in existing technologies.

[0020] Figure 2 This is a schematic diagram of a convex groove structure in the prior art;

[0021] Figure 3 Schematic diagram of the structure of this invention;

[0022] Figure 4 for Figure 3 Enlarged view of area A in the image;

[0023] Figure 5 The Pareto optimal solution set calculated by the particle swarm optimization algorithm;

[0024] Figure 6 The slot dimensions are optimized using the particle swarm optimization algorithm.

[0025] Figure 7 The starting current and starting torque are optimized for the particle swarm optimization algorithm.

[0026] In the figure: 1. Rotor core; 2. Convex slot; 20. Top-level slot section; 21. Bottom-level slot section; 3. Rotor teeth. Detailed Implementation

[0027] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0028] like Figures 3-4 The rotor shown is suitable for starting an induction motor with power supply over long distances. It includes a rotor core 1 with multiple convex slots 2. Rotor teeth 3 are formed between any two adjacent convex slots 2. The convex slots 2 include a top slot portion 20 and a bottom slot portion 21 that are interconnected. The bottom slot portion 21 is farther away from the air gap than the top slot portion 20, or in other words, the bottom slot portion 21 is closer to the axis of the rotor core 1 than the top slot portion 20. The top slot portion 20 is a parallel slot. The slot width of the bottom slot portion 21 gradually narrows from the side closer to the top slot portion 20 to the side farther away from the top slot portion 20.

[0029] Compared with existing parallel teeth, the rotor tooth section 3 of this application has a larger effective rotor slot area when consuming the same magnetic flux. When the slot depth is large, the lamination utilization area is larger, which can effectively reduce aluminum consumption and improve the efficiency of the motor.

[0030] Preferably, the convex groove is a two-part semi-open groove.

[0031] Preferably, the convex groove 2 is an axial inclined groove.

[0032] Preferably, the depth of the top-level groove portion 20 is less than the depth of the bottom-level groove portion 21.

[0033] Preferably, when the rotor is used in an induction motor with a power greater than or equal to 100kW, the groove depth of the convex groove 2 is greater than 45mm; when the rotor is used in an induction motor with a power less than 100kW, the groove depth of the convex groove 2 is less than 30mm. This convex groove 2, when the groove depth is larger, has a larger groove leakage resistance during startup and a smaller groove leakage resistance during operation compared to a parallel groove, thus simultaneously meeting the requirements for both startup and running performance.

[0034] Preferably, the width of the top groove portion 20 is smaller than the bottom width of the bottom groove portion 21.

[0035] A rotor optimization method for a remote power supply starting induction motor, used to optimize the rotor convex slot 2 structure described above, includes the following steps:

[0036] S1: Establish the rotor model described above and match it with the stator to form a motor model;

[0037] S2: Perform finite element simulation on the motor model formed in S1, and obtain the effective value of the corresponding starting current by analyzing the stall current in the simulation results.

[0038] S3: The particle swarm optimization algorithm is used to optimize the groove depth hup and groove width bup of the top groove part 20 of the rotor convex groove 2, the groove depth hdown and bottom width bdown of the bottom groove part 21 as optimization factors, and the finite element optimization software is used for optimization calculation and analysis.

[0039] S4: Optimization factors for selecting motors to obtain minimum starting current and maximum starting torque.

[0040] Taking the YKK5004-6 high-voltage induction motor as an example, the motor has a rated output power of 900kW, a rated voltage of 10kV, 6 poles, a stator outer diameter of 850mm, a stator inner diameter of 590mm, a rotor inner diameter of 350mm, an air gap of 1.8mm, and a stator core with 72 straight slots and double-layer windings.

[0041] like Figures 3-4As shown, the present invention provides a rotor suitable for long-distance power supply starting induction motor. The rotor is a cast aluminum rotor. The rotor core 1 has 86 convex slots 2, all of which are semi-closed slots with an oblique slot structure. The convex slots 2 are divided into upper and lower levels. The level closer to the air gap is called the top level slot 20, and the level further away from the air gap is called the bottom level slot 21. The top level slot 20 has a parallel slot structure with a slot depth of hup and a slot width of bup. Its skin effect is more significant than that of the parallel tooth slot type, which is beneficial to improving starting performance. The rotor teeth 3 corresponding to the bottom level slot 21 have a parallel tooth structure with a slot depth of hdown and a bottom width of bdown.

[0042] The rotor is as follows Figure 1 When the pear-shaped slot is shown, the relevant performance parameters of the motor are initially obtained by the RMxprt module in the finite element software. The starting current amplitude is 234.812A, the effective value is 166.037A, the effective value of the starting torque is 8678.62Nm, and the efficiency is 95.3476%.

[0043] For the rotor convex groove 2 structure in this embodiment ( Figure 3-4 A stall simulation was performed on the rotor convex slot 2 structure shown. The stator matched with the rotor is a general stator with an outer diameter of 850 mm and an inner diameter of 590 mm. The motor with the rotor convex slot 2 structure was simulated using finite element software, and the motor speed was set to 0 rpm. By analyzing the stall current in the simulation results, the effective value of the corresponding starting current can be obtained.

[0044] like Figure 5-7 As shown, a particle swarm optimization algorithm is used, with the goal of obtaining a larger starting torque and a smaller starting current. The groove depth hup and groove width bup of the top-level groove 20 of the rotor convex groove 2, and the groove depth hdown and bottom width bdown of the bottom-level groove 21 are used as optimization factors. Finite element optimization software is used for optimization calculation and analysis, resulting in the following... Figure 5 The Pareto optimal solution set shown in the figure has a solid black circle in the lower left corner representing the optimal solution. There is more than one optimal solution, and the choice needs to be made based on the actual situation. The result is as follows: Figure 6 When the motor shown obtains the minimum starting current and the maximum starting torque, the top slot 20 of the rotor convex slot 2 has a slot depth hup of 20.836 mm and a slot width bup of 3.00657 mm, and the bottom slot 21 has a slot depth hdown of 47.2446 mm and a bottom width bdown of 6.0442 mm.

[0045] like Figure 7 As shown, these four parameters were brought back into the finite element software model and the simulation was performed again. The effective value of the minimum starting current was 132.709A, and the effective value of the maximum starting torque was 9810.9Nm. (This is in contrast to...) Figure 1Compared to the pear-shaped slot shown, the motor with the convex slot 2 rotor has a starting current that is reduced by about 20% and a starting torque that is increased by about 13%. While ensuring that the operating performance meets the requirements, the convex slot 2 rotor structure motor significantly increases the starting torque and significantly reduces the starting current, effectively improving the starting performance of induction motors for long-distance power supply.

[0046] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0048] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A rotor optimization method suitable for long-distance power supply starting induction motors, characterized in that, The rotor includes a rotor core (1), on which a plurality of convex slots (2) are formed. Each convex slot (2) includes a top-level slot portion (20) and a bottom-level slot portion (21) that are interconnected. The bottom-level slot portion (21) is farther away from the air gap than the top-level slot portion (20). The top-level slot portion (20) is a parallel slot. The slot width of the bottom-level slot portion (21) gradually narrows from the side closer to the top-level slot portion (20) to the side farther away from the top-level slot portion (20). The rotor optimization method is used to optimize the structure of the rotor convex slots (2), and includes the following steps: S1: Establish a rotor model and match the rotor model with the stator to form a motor model; S2: Perform finite element simulation on the motor model formed in S1, and obtain the effective value of the corresponding starting current by analyzing the stall current in the simulation results; S3: The particle swarm optimization algorithm is used to optimize the groove depth hup and groove width bup of the top groove part (20) of the rotor convex groove (2), the groove depth hdown and bottom width bdown of the bottom groove part (21) as optimization factors, and the finite element optimization software is used for optimization calculation and analysis. S4: Optimization factors for selecting motors to obtain minimum starting current and maximum starting torque.

2. The rotor optimization method suitable for the remote power supply starting of the induction motor according to claim 1, characterized in that, The convex groove (2) is a semi-open groove.

3. The rotor optimization method suitable for the remote power supply starting of the induction motor according to claim 1, characterized in that, The convex groove (2) is an axial inclined groove.

4. The rotor optimization method suitable for the remote power supply starting of the induction motor according to claim 1, characterized in that, The depth of the top-level groove (20) is less than the depth of the bottom-level groove (21).

5. The rotor optimization method suitable for the remote power supply starting of the induction motor according to claim 1, characterized in that, When the rotor is used for an induction motor with a power greater than or equal to 100kW, the groove depth of the convex groove (2) is greater than 45mm. When the rotor is used for an induction motor with a power less than 100kW, the groove depth of the convex groove (2) is less than 30mm.

6. The rotor optimization method suitable for the remote power supply starting of an induction motor according to claim 1, characterized in that, The width of the top-level groove portion (20) is smaller than the minimum width of the bottom-level groove portion (21).

Images