CN117097043A - Brushless alternating current exciter stator structure for reducing torque pulsation and design method thereof - Google Patents

Brushless alternating current exciter stator structure for reducing torque pulsation and design method thereof Download PDF

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Publication number
CN117097043A
CN117097043A CN202310874264.9A CN202310874264A CN117097043A CN 117097043 A CN117097043 A CN 117097043A CN 202310874264 A CN202310874264 A CN 202310874264A CN 117097043 A CN117097043 A CN 117097043A
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CN
China
Prior art keywords
stator
groove
width
pole
height
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Application number
CN202310874264.9A
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Chinese (zh)
Inventor
鲍晓华
赵博
刘业军
翁德红
田康
狄冲
黄贤法
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Anhui Eggset Electric Technology Co ltd
Hefei University of Technology
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Anhui Eggset Electric Technology Co ltd
Hefei University of Technology
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Application filed by Anhui Eggset Electric Technology Co ltd, Hefei University of Technology filed Critical Anhui Eggset Electric Technology Co ltd
Priority to CN202310874264.9A priority Critical patent/CN117097043A/en
Publication of CN117097043A publication Critical patent/CN117097043A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/16—Stator cores with slots for windings
    • H02K1/165—Shape, form or location of the slots
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
    • H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)

Abstract

The application discloses a stator structure for reducing torque pulsation of a brushless alternating current exciter and a design method thereof. The application can effectively improve the conditions of high magnetic density at the two sides of the stator pole of the brushless alternating current exciter and low magnetic density at the central axis, and reduce the torque pulsation of the motor.

Description

Brushless alternating current exciter stator structure for reducing torque pulsation and design method thereof
Technical Field
The application relates to the technical field of motors, in particular to a brushless alternating current exciter stator structure for reducing torque pulsation and a design method thereof.
Background
Brushless ac exciter machines are commonly used in large power plants and function to provide exciting current to a main generator, one of the core components in a generator set. The brushless alternating current exciter, the rotary rectifier and the main generator coaxially rotate, and in the actual operation process, the connecting part of the brushless alternating current exciter and the main generator and the rotating shaft simultaneously provide traction force for the brushless alternating current exciter. If the torque ripple of the brushless ac exciter is too large, the metal fatigue damage at the connection part is caused to a certain extent, and the risk of disconnection from the main generator is generated.
Disclosure of Invention
Aiming at the problem of larger torque pulsation when the load of the brushless alternating current exciter fluctuates, the application provides a brushless alternating current exciter stator structure for reducing the torque pulsation and a design method thereof, and the reliability of a generator set is improved.
The stator structure for reducing torque pulsation of the brushless alternating current exciter comprises a stator body, wherein a yoke part and stator teeth are arranged on the stator body, the stator teeth comprise pole shoes and pole bodies, the pole bodies are used for connecting the pole shoes with the yoke part, through grooves are formed in the stator teeth, and the centers of the through grooves are positioned on connecting lines of the pole bodies and the pole shoe connecting points.
Preferably, one of the stator teeth is provided with two through grooves, and the two through grooves are symmetrical relative to the pole shoe along the radial central line of the stator.
Preferably, the through groove is rectangular.
Preferably, the width of the through groove is b 1 ，b 1 ＝k 3 l 3 Wherein: l (L) 3 For the width of the pole body, k 3 K is obtained by experiment for the width coefficient of the through groove 3 Taking 0.1-0.5 optimally.
Preferably, the height of the through groove is h 4 ，h 4 ＝k 4 h 3 Wherein: k (k) 4 For the height coefficient of the through groove, through experiment k 4 Taking 0.2 to 1, optimally, h 3 Is the pole shoe height.
As a further optimized scheme of the application, the application further comprises an extension groove, wherein the extension groove is communicated with the through groove, the width of the extension groove is equal to that of the through groove, one side wall of the extension groove along the height direction is in the same plane with one side wall of the through groove along the height direction, the other side wall of the extension groove along the height direction is in the same plane with the other side wall of the through groove along the height direction, and one side wall of the extension groove far away from the through groove extends to the yoke part.
A brushless alternating current exciter stator structure design method for reducing torque pulsation comprises the following steps:
step 1: according to the formulaDetermining pole shoe arc length, wherein: l (L) 1 Is the arc length of the pole shoe, k 1 D is the ratio of the arc length of all pole shoes to the inner circumference of the stator 1 Is the stator inner diameter, p is the motor pole pair number, k 1 Take 0 to 1, preferably take k 1 ＝0.7；
Step 2: determining pole shoe width by the formulaThe angle of the pole shoe is brought into a pole shoe angle calculation formula, and can be obtained,wherein: l (L) 2 Is the width of the pole shoe;
wherein:determining an angle corresponding to the pole shoe, wherein: θ the angle corresponding to the pole shoe arc length is the angle of the pole shoe arc length relative to the axis of the stator;
step 3: determining pole body widthThe formula is l 3 ＝k 2 l 2 Wherein: l (L) 3 For the width of the pole body, k 2 K is the proportionality coefficient of the width of the pole body and the width of the pole shoe 2 Take 0 to 1, preferably take k 2 ＝0.75；
Step 4: determining the height of the pole body by the formula ofDetermining a pole body contact position with the pole shoe, wherein: h is a 1 For the height of the pole body, D 2 Is the outer diameter of the stator, h 2 Is the height of the yoke part of the stator, h 3 Is the height of the pole shoe;
step 5: determining the width of the through groove, wherein the formula is b 1 ＝k 3 l 3 ，b 1 To pass groove width, k 3 To be the through groove width coefficient, k 3 Taking 0.1 to 0.5, preferably, taking k 3 ＝0.28；
Step 6: determining the height of the through groove, wherein the formula is h 4 ＝k 4 h 3 ，h 4 To pass groove height, k 4 For the height coefficient of the through groove, through experiment k 4 Most preferably, k is taken when 0.2 to 1 is taken 4 ＝0.8；
Step 7: after the contact position of the pole shoe and the pole body is determined (the contact position of the pole shoe and the pole body can be determined by determining the width height of the pole shoe, the corresponding angle of the pole shoe and the arc length of the pole shoe), two through grooves with the sizes calculated in the step 6 and the step 5 are formed on the left side and the right side of the stator tooth, the center line of the height of the through groove corresponds to the contact position, namely, the center line of the through groove along the width direction coincides with the connecting line of the contact point of the pole shoe and the pole body, and the midpoint of the through groove is ensured to be on the connecting line of the contact point of the pole shoe and the pole body.
As a further optimized scheme of the application, the method further comprises the following steps: in the step 6, the bottom end of the through slot is kept unchanged and the width is unchanged, and the through slot extends upwards to the stator yoke part along the height direction of the through slot, that is, the extending slot structure is formed.
According to the stator, the pole body and the pole shoe are determined according to the inner diameter and the outer diameter of the stator and the yoke part, so that the shape and the position of a through slot are determined, the magnetic induction intensity of the central axis of a stator pole is increased, the air gap flux density is optimized, the air gap harmonic wave is reduced, and finally the torque pulsation of the motor is reduced; the application can effectively improve the conditions of high magnetic density at the two sides of the stator pole of the brushless alternating current exciter and low magnetic density at the central axis, and reduce the torque pulsation of the motor.
Compared with the prior art, the application has the beneficial effects that:
(1) According to the stator structure for reducing torque pulsation of the brushless alternating current exciter and the design method thereof, through arranging the through grooves at the opposite positions of the pole shoes and the pole body connection positions, the air gap flux density of the motor is improved, and the torque pulsation is reduced;
aiming at the actual working condition of the brushless alternating current exciter, the method considers the problem that excessive torque pulsation can cause metal fatigue at the joint, and through reasonably designing stator poles, through slots are added in the prior art, the air gap flux density of the motor is improved, and the torque pulsation is reduced.
(2) The application has simple structure, obvious torque pulsation reducing effect and wide universality.
Additional aspects and advantages of the application 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 application.
Drawings
FIG. 1 is a schematic diagram of a prior art motor stator core;
FIG. 2 is a schematic view of a stator core structure according to the present application;
FIG. 3 is a schematic view of a stator pole structure according to the present application;
FIG. 4 is a waveform of the air gap flux density of a brushless AC exciter with and without slots in the stator, with the abscissa being the electrical angle;
FIG. 5 is a torque waveform of a brushless AC exciter with and without slots in the stator, with time on the abscissa;
FIG. 6 is a schematic diagram of a simulation of the first embodiment and the prior art;
FIG. 7 is a schematic diagram of simulation of the second embodiment and the prior art;
reference numerals in the drawings: 1. a stator yoke part, 2, a pole body, 3 and a through groove,4. pole shoe D 1 Stator inner diameter D 2 An angle corresponding to the outer diameter of the stator, the arc length of the theta pole shoe, h 1 Pole body height, h 2 Stator yoke height, h 3 Pole shoe height, l 1 Pole shoe arc length l 2 Pole shoe width, l 3 Width of pole body, contact position of A pole body and pole shoe, b 1 Width of through groove, h 4 Through groove height.
Detailed Description
The following detailed description of embodiments of the application is exemplary, and is presented only to illustrate the application and not to limit the application.
Example 1
As shown in fig. 2-3, a stator structure for reducing torque pulsation of a brushless alternating current exciter comprises a stator body, wherein a yoke part 1 and stator teeth are arranged on the stator body, the stator teeth comprise pole shoes 4 and pole bodies 2, the pole bodies 2 connect the pole shoes 4 with the yoke part 1, through grooves 3 are formed in the stator teeth, and the centers of the through grooves 3 are positioned on connecting lines of connecting points of the pole bodies 2 and the pole shoes 4;
specifically, one of the stator teeth is provided with two through slots 3, the two through slots 3 are symmetrical relative to the pole shoe 4 along the radial central line of the stator, in this embodiment, preferably, the through slots 3 are rectangular, and the width of the through slots 3 is b 1 ，b 1 ＝k 3 l 3 Wherein: l (L) 3 For the width of the pole body 2, k 3 For the width coefficient of the through groove 3, k 3 Taking 0.1 to 0.5;
the height of the through groove 3 is h 4 ，h 4 ＝k 4 h 3 Wherein: k (k) 4 For the height coefficient of the through groove 3, k 4 Taking 0.2 to 1 h 3 Is the pole shoe 4 height.
It will be appreciated by those skilled in the art from the above formulas that the configuration of the through slots 3 described above can be determined directly from the existing width of the pole body 2 and height of the pole pieces 4.
As shown in fig. 2, the known stator outer diameter D 2 650mm stator inside diameter D 1 354mm, 348mm rotor outer diameter, 180mm rotor inner diameter, 1 height h of stator yoke 2 Is 50mm in diameter and is suitable for the treatment of the steel plate,pole shoe 4 height h 3 15mm, the pole pair number p of the motor is 4;
the design method of the stator structure for reducing the torque pulsation of the brushless alternating current exciter comprises the following steps:
step 1: according to the formulaDetermining the arc length, k, of pole shoe 4 1 For all pole pieces 4 arc length and proportionality coefficient to stator inner circumference, D 1 Is the inner diameter of the stator, p is the pole pair number of the motor, and k is taken 1 =0.77, determining pole piece 4 arc length l 1 ＝97.31mm；
Step 2: according to the formulaAs shown in fig. 2, θ is the angle corresponding to the arc length of the pole piece 4, i.e., the angle of the pole piece 4 arc length relative to the stator axis, determines the width l of the pole piece 4 2 ＝96.1mm；
Step 3: taking k 2 Determine the width l of pole body 2 =0.75 3 ＝k 2 l 2 ＝72.1mm；
Step 4:determining the height h of the pole body 2 1 ＝83mm；
Step 5: according to formula b 1 ＝k 3 l 3 Calculating the width of the through groove 3 according to the formula h 4 ＝k 4 h 3 Calculating the height of the through groove 3 and taking k 3 ＝0.28，k 4 =0.8, determining the width b of the through slot 3 1 Pass groove 3 height h =20.12 mm 4 ＝12mm；
(7) After the contact position of the pole shoe 4 and the pole body 2 is determined, (the contact position of the pole shoe 4 and the pole body 2 can be determined by determining the width and the height of the pole body 2, the corresponding angle of the pole shoe 4 and the arc length of the pole shoe 4) two through grooves 3 with calculated sizes are formed on the left side and the right side of the stator tooth, the center line of the height corresponds to the contact position, namely, the center line of the through groove 3 along the width direction coincides with the connecting line of the contact point of the pole shoe 4 and the pole body 2, and the midpoint of the through groove 3 is ensured to be positioned on the connecting line of the contact point of the pole shoe 4 and the pole body 2, as shown in fig. 3.
The stator structure designed in the prior art (the stator structure shown in fig. 1) is different from the stator structure calculated in the above-mentioned manner by using finite element software, in that the through slot 3 is not formed in fig. 1, other dimensions are the same as those of the stator calculated in the above-mentioned manner, and the stator structure (the stator structure shown in fig. 2-3) in this embodiment is subjected to simulation with a rated power of 46kW, and the load resistance is set to 0.516 Ω. By comparing the waveforms of the air gap magnetic densities of the two, as shown in fig. 5, the brushless ac exciter in the embodiment improves the air gap magnetic density near the center line position of the stator pole, suppresses the magnetic density at two sides, and improves the condition that the air gap magnetic field is unevenly distributed under the stator pole.
As shown in fig. 6, the stator structure of the prior art design has an average torque of-135.2n.m, a required load torque of-181n.m at maximum, a required load torque of-93.9n.m at minimum, and a torque ripple of 64.4%; while the average torque in this example was-121.7n.m, the required load torque was-158.5n.m at maximum, the required load torque was-89 n.m at minimum, and the torque ripple was 57.1%. It can be obtained that the load average torque required for the stator structure in this embodiment is reduced by 13.5n.m and the torque ripple is reduced by 7.3% compared to the prior art.
Example two
The stator structure for reducing torque ripple of the brushless ac exciter is different from the above embodiment in that, as shown in fig. 4, the stator structure further includes an extension groove, the extension groove is communicated with the through groove 3, the width of the extension groove is equal to the width of the through groove 3, one side wall of the extension groove along the height direction is in the same plane with one side wall of the through groove 3 along the height direction, the other side wall of the extension groove along the height direction is in the same plane with the other side wall of the through groove 3 along the height direction, and one side wall of the extension groove far away from the through groove 3 extends to the stator yoke 1.
The design method of the stator structure for reducing torque pulsation of the brushless alternating current exciter of the embodiment is based on the design method of the embodiment, and further comprises the following steps: in the step 6, the bottom end of the through slot 3 is kept unchanged and the width is unchanged, and the through slot 3 extends upwards to the stator yoke 1 along the height direction of the through slot 3, i.e. the above-mentioned extending slot structure is formed.
The stator of this embodiment has the same size as the stator of the embodiment, and the only difference is that the embodiment is also provided with an extension slot structure, and the stator of this embodiment is simulated with the existing stator, specifically, as shown in fig. 7, the average torque of the rectangular slot with the top extending to the stator yoke 1 is-95.1 n.m, the required load torque is-124.2 n.m at maximum, the required load torque is-69.3 n.m at minimum, and the torque ripple is 57.7%, and compared with the prior art, the torque ripple is reduced by 6.7%.
The foregoing is only a preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art, who is within the scope of the present application, should make equivalent substitutions or modifications according to the technical scheme of the present application and the inventive concept thereof, and should be covered by the scope of the present application.

Claims (10)

1. The stator structure is characterized in that a through groove is formed in the stator tooth, and the center of the through groove is positioned on a connecting line of a pole body and a pole shoe connecting point.
2. A brushless ac exciter torque ripple reducing stator structure in accordance with claim 1, wherein one of said stator teeth is provided with two of said through slots, said two through slots being symmetrical about said pole piece along a radial centerline of said stator.
3. A brushless ac exciter torque ripple reducing stator structure in accordance with claim 1 or 2, wherein said through slots are rectangular.
4. A reduced brushless ac excitation according to claim 3The stator structure of the motor torque pulsation is characterized in that the width of the through groove is b 1 ，b 1 ＝k 3 l 3 Wherein: l (L) 3 For the width of the pole body, k 3 To be the through groove width coefficient, k 3 Taking 0.1 to 0.5.
5. A brushless ac exciter torque ripple reducing stator structure in accordance with claim 3, wherein said through slots have a height h 4 ，h 4 ＝k 4 h 3 Wherein: k (k) 4 For the height coefficient of the through slot, k 4 Taking 0.2 to 1 h 3 Is the pole shoe height.
6. The brushless ac exciter torque ripple reducing stator structure of claim 5, further comprising an extension groove, said extension groove communicating with said through groove, said extension groove having a width equal to a width of said through groove, a side wall of said extension groove in a height direction being in a same plane as a side wall of said through groove in a height direction, another side wall of said extension groove in a height direction being in a same plane as another side wall of said through groove in a height direction, said extension groove extending away from a side wall of said through groove to said yoke.
7. A stator structural design method for reducing torque ripple of a brushless ac exciter, comprising the steps of:
step 1: calculating the arc length of the pole shoe, wherein the formula isWherein: l (L) 1 Is the arc length of the pole shoe, k 1 D is the pole shoe arc length and the proportionality coefficient to the stator inner circumference 1 Is the stator inner diameter, p is the motor pole pair number;
step 2: calculating the width of the pole shoe, wherein the formula isWherein: l (L) 2 Is of the width of the pole shoeA degree;
step 3: calculating the width of the pole body, wherein the formula is l 3 ＝k 2 l 2 Wherein: l (L) 3 For the width of the pole body, k 2 The ratio coefficient of the width of the pole body to the width of the pole shoe;
step 4: calculating the height of the pole body, the formula isWherein: h is a 1 For the height of the pole body, D 2 Is the outer diameter of the stator, h 2 Is the height of the yoke part of the stator, h 3 Is the height of the pole shoe;
step 5: calculating the width of the through groove, wherein the formula is b 1 ＝k 3 l 3 ，b 1 To pass groove width, k 3 To be the through groove width coefficient, k 3 The value is 0.1 to 0.5;
step 6: determining the height of the through groove, wherein the formula is h 4 ＝k 4 h 3 ，k 4 For the height coefficient of the through slot, k 4 The value range is 0.2-1;
step 7: and (3) forming through grooves with the sizes calculated in the step (5) and the step (6) on the stator teeth, wherein the central line of the through grooves along the width direction coincides with the connecting line of the pole shoe and the pole body contact point.
8. The stator structural design method for reducing torque ripple of a brushless ac exciter of claim 1, wherein: in step 1, k 1 Taking 0 to 1.
9. The stator structural design method for reducing torque ripple of a brushless ac exciter of claim 1, wherein: k in step 3 2 Taking 0 to 1.
10. The stator structural design method for reducing torque ripple of a brushless ac exciter of claim 5, wherein: further comprising step 8: the bottom position and the width of the through slot are kept unchanged, and the top position of the through slot is prolonged to the stator yoke.
CN202310874264.9A 2023-07-17 2023-07-17 Brushless alternating current exciter stator structure for reducing torque pulsation and design method thereof Pending CN117097043A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310874264.9A CN117097043A (en) 2023-07-17 2023-07-17 Brushless alternating current exciter stator structure for reducing torque pulsation and design method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310874264.9A CN117097043A (en) 2023-07-17 2023-07-17 Brushless alternating current exciter stator structure for reducing torque pulsation and design method thereof

Publications (1)

Publication Number Publication Date
CN117097043A true CN117097043A (en) 2023-11-21

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310874264.9A Pending CN117097043A (en) 2023-07-17 2023-07-17 Brushless alternating current exciter stator structure for reducing torque pulsation and design method thereof

Country Status (1)

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