CN111245125B - Rotor magnetic pole segmented permanent magnet synchronous motor and electromagnetic vibration weakening method thereof - Google Patents

Rotor magnetic pole segmented permanent magnet synchronous motor and electromagnetic vibration weakening method thereof Download PDF

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CN111245125B
CN111245125B CN202010059019.9A CN202010059019A CN111245125B CN 111245125 B CN111245125 B CN 111245125B CN 202010059019 A CN202010059019 A CN 202010059019A CN 111245125 B CN111245125 B CN 111245125B
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pole
rotor
permanent magnet
motor
stator
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CN111245125A (en
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王道涵
彭晨
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Shandong University
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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
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/278—Surface mounted magnets; Inset magnets
    • 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
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/02—Details
    • H02K21/021—Means for mechanical adjustment of the excitation flux
    • H02K21/028—Means for mechanical adjustment of the excitation flux by modifying the magnetic circuit within the field or the armature, e.g. by using shunts, by adjusting the magnets position, by vectorial combination of field or armature sections
    • H02K21/029—Vectorial combination of the fluxes generated by a plurality of field sections or of the voltages induced in a plurality of armature sections
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
    • 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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  • Power Engineering (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)

Abstract

The invention provides a rotor magnetic pole segmented permanent magnet synchronous motor and an electromagnetic vibration weakening method thereof, wherein the rotor magnetic pole segmented permanent magnet synchronous motor comprises a stator, a permanent magnet rotor and an armature winding, the permanent magnet rotor comprises a rotor core and a permanent magnet, the permanent magnet rotor is sleeved in the stator and is coaxially arranged with the stator, and the stator is provided with the armature winding; the permanent magnet rotor is divided into two sections along the axial direction, the two sections of the permanent magnet rotors are completely identical in structure and are installed in a staggered mode along the axial direction, 2p permanent magnets are placed on the surface of each section of the rotor, p is the number of pole pairs of the motor, the width of a pole arc corresponding to one permanent magnet in the permanent magnets is different from the width of pole arcs corresponding to other permanent magnets, and the width of pole arcs of other 2p-1 permanent magnets is the same. The suppression of torque pulsation and electromagnetic vibration of the surface-mounted permanent magnet motor under the condition of the non-oblique pole chute can be realized, and the input cost is low.

Description

Rotor magnetic pole segmented permanent magnet synchronous motor and electromagnetic vibration weakening method thereof
Technical Field
The invention belongs to the technical field of electromagnetic vibration weakening, and relates to a rotor magnetic pole segmented permanent magnet synchronous motor and an electromagnetic vibration weakening method thereof.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
In recent years, with the improvement of high temperature resistance and the reduction of price of permanent magnet materials, permanent magnet motors are widely applied in national defense, industry, agriculture and daily life, and are developing towards high power, high functionality and miniaturization, and the variety and application field of the permanent magnet motors are continuously expanded. At present, the power of the permanent magnet motor ranges from several milliwatts to several kilowatts, the application range is from small to toy motors and large to large permanent magnet motors used for ship traction, and the permanent magnet motor is widely applied to various aspects of national economy, daily life, military industry and aerospace.
Generally speaking, the servo control systems of the above application fields are generally feedback control systems for accurately following or reproducing a certain process. In many cases, a servo system refers to a feedback control system in which the controlled variable (the output quantity of the system) is mechanical displacement or displacement speed, acceleration, and the function of the feedback control system is to make the output mechanical displacement (or rotation angle) accurately track the input displacement (or rotation angle), and the control precision is high. The surface-mounted permanent magnet motor is a non-salient pole motor, has equal quadrature-direct axis inductance and good control performance, is very suitable for being used as a permanent magnet alternating current servo motor in a servo control system, and has the following two main advantages:
(1) the permanent-magnet synchronous motor has the advantages of simple structure, lower manufacturing cost and small rotational inertia, thereby being widely applied to the rectangular wave permanent-magnet synchronous motor and the sine wave permanent-magnet synchronous motor with a narrow constant-power operation range.
(2) The permanent magnetic pole in the surface-mounted rotor structure is easy to realize the optimal design, so that the permanent magnetic pole is in a magnetic pole shape which can enable the air gap magnetic flux density waveform of the motor to approach to a sine wave, and the performance of the motor and even the whole transmission system can be obviously improved.
However, surface-mounted permanent magnet motors also have the common disadvantage of permanent magnet motors, namely having cogging torque. The existence of the cogging torque can increase the torque pulsation of the permanent magnet motor, is not beneficial to the application of the motor to high-precision control occasions, and can bring extra electromagnetic vibration to the motor. At present, the cogging torque, the torque pulsation and the electromagnetic vibration of the permanent magnet motor are weakened mainly by adopting a stator skewed slot or a rotor skewed pole in the industry, but the difficulty and the cost of industrial manufacturing are increased by adopting a skewed pole or a skewed slot mode, and the method is difficult to realize when the axial length of the motor is short.
Disclosure of Invention
The invention provides a rotor magnetic pole segmented permanent magnet synchronous motor and an electromagnetic vibration weakening method thereof in order to solve the problems.
According to some embodiments, the invention adopts the following technical scheme:
a rotor magnetic pole segmented permanent magnet synchronous motor comprises a stator, a permanent magnet rotor and an armature winding, wherein the permanent magnet rotor comprises a rotor iron core and a permanent magnet, the permanent magnet rotor is sleeved inside the stator and is arranged coaxially with the stator, and the armature winding is arranged on the stator;
the permanent magnet rotor is divided into two sections along the axial direction, the two sections of the permanent magnet rotors are completely identical in structure and are installed in a staggered mode along the axial direction, 2p permanent magnets are placed on the surface of each section of the rotor, p is the number of pole pairs of the motor, the width of a pole arc corresponding to one permanent magnet in the permanent magnets is different from the width of pole arcs corresponding to other permanent magnets, and the width of pole arcs of other 2p-1 permanent magnets is the same.
As an alternative embodiment, the two sections of permanent magnet rotors are staggered by 180 degrees along the axial direction when being installed, and two key slots which are symmetrical up and down are arranged on the rotor shaft. The staggered installation of the two sections of rotors in the processing and assembling process is convenient.
In an alternative embodiment, the rotor poles with unequal pole arc widths in the two-segment rotor are symmetrically distributed along the center of the rotor, and the magnetic flux of the whole rotor is symmetrically distributed along the rotor. The unbalanced radial magnetic pull force caused by the unequal magnetic pole widths of the rotor can be completely counteracted, and the electromagnetic vibration during the running of the motor is further reduced.
As an alternative embodiment, a plurality of stator slots are arranged on the stator, and the stator slots are in a straight slot structure.
As a further limitation, the armature windings are housed in stator slots, and the two segments of permanent magnet rotors are arranged concentrically with the stator.
A method for weakening electromagnetic vibration of a rotor magnetic pole segmented permanent magnet synchronous motor comprises the following steps: divide into two sections with permanent magnet rotor along axial direction, two sections permanent magnet rotor's structure is the same completely, and staggers the installation along the axial, has placed 2p permanent magnet on every section rotor surface, and wherein p is the pole pair number of motor, the pole arc width that corresponds of a permanent magnet among the permanent magnet is different with the pole arc width that corresponds of other permanent magnets, and the pole arc width of other 2p-1 permanent magnets is the same.
As a further limitation, the permanent magnets with different magnetic pole widths are set to correspond to a pole arc width thetaaThe other 2p-1 permanent magnets with the same magnetic pole width correspond to the pole arc width thetabThe width between poles between two adjacent magnetic poles is thetacAnd is provided with KtThe ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the pole arc widths of other magnetic poles, the process of determining the pole arc width corresponding to each permanent magnet includes:
from analytical calculations, the expression for cogging torque is expressed as:
Figure BDA0002373796480000041
in the formula, LaIs the axial length, R, of the armature core1And R2Respectively, the outer radius of the armature and the inner radius of the stator yoke, n is an integer such that nz/2p is an integer, z is the number of stator teeth, mu0Is a vacuum magnetic permeability.
When the rotor magnetic poles have unequal pole arc widths, B thereofrnThe Fourier expansion of (A) is:
Figure BDA0002373796480000042
in the formula, KtIs the ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the other magnetic poles, p is the pole pair number, thetacThe inter-pole width between two magnetic poles.
The width theta of the pole arc corresponding to the permanent magnetaAnd thetabBy BrnIn the expanded form of (K)tSelecting K and determining the pole arc coefficient of the original motor according to the performance and design principle of the motortWhen, should choose the nearest 1 and let BrnK equal to 0tValue of thetaaAnd thetabThe difference of (a) is minimal.
By way of further limitation, the number of stator slots corresponding to rotor poles formed by permanent magnets with different pole arc widths is:
Figure BDA0002373796480000051
wherein Z is the number of stator teeth, p is the number of pole pairs, KtThe ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the other magnetic poles.
By way of further limitation, the number of stator slots corresponding to rotor magnetic poles formed by 2p-1 permanent magnets with the same pole arc width is as follows:
Figure BDA0002373796480000052
wherein Z is the number of stator teeth, p is the number of pole pairs, KtThe ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the other magnetic poles.
Compared with the prior art, the invention has the beneficial effects that:
1. the stator of the motor is of a straight slot structure, and compared with the skewed slot stator commonly used in the industry at present, the stator of the motor is low in processing cost and simple in processing technology, and can effectively increase the manufacturing efficiency of the motor and reduce the manufacturing cost of the motor.
2. Compared with the conventional torque pulsation weakening method (stator chute or rotor oblique pole), the permanent magnet consumption and the effective magnetic flux of each pole of the motor are the same, so that the effective magnetic flux of each pole is not reduced or increased, the material consumption is the same as that of the conventional motor, and the manufacturing cost of the motor is not increased.
3. The permanent magnet rotors of the motor are staggered by 180 degrees when being assembled, unbalanced radial magnetic tension caused by unequal pole widths of the rotors can be completely offset, and compared with torque pulsation weakening modes (such as magnetic pole deviation) of other asymmetric structures, the motor reduces electromagnetic vibration generated by unbalanced magnetic circuits, and compared with a traditional motor, reduces electromagnetic vibration generated by torque fluctuation.
4. The stator of the motor is of a straight slot structure, compared with a skewed slot stator commonly used in the industry at present, the stator does not bring extra axial force, the axial force of the motor is equivalent to that of a traditional straight slot motor, and the electromagnetic vibration caused by the axial force of the motor can be further reduced.
5. The rotor shaft of the motor is provided with the two key slots which are symmetrical up and down, so that the staggered installation of the two sections of rotors in the process of processing and assembling is facilitated, the processing cost of two sets of dies required by the staggered installation of the traditional single-key-slot rotor is saved, and the manufacturing difficulty and the processing cost are reduced. The two key grooves are symmetrically distributed, the staggered angle is 180 degrees, and compared with the traditional magnetic pole segmentation method, the staggered angle is large. The double-key-groove design of the motor obviously reduces the processing difficulty in the process and is easy to realize.
6. The method for weakening the cogging torque of the motor is realized by arranging unequal magnetic pole widths, and compared with the traditional magnetic pole segmented motor, the method has better effect of weakening the cogging torque. The weakening degree of the traditional magnetic pole segmented motor to the cogging torque is related to the number of the segments of the rotor, and the cogging torque of the permanent magnet motor cannot be completely eliminated theoretically; the motor can theoretically completely eliminate the cogging torque of the permanent magnet motor by a method of unequal magnetic pole widths, and the weakening effect of the cogging torque of the motor is superior to that of the traditional magnetic pole segmented motor.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
Fig. 1 is a structural view of a motor embodiment 1 of the present invention;
fig. 2 is a schematic illustration of the unequal pole arc width form of the permanent magnet in motor embodiment 1 of the present invention, wherein (a) is a rotor of a conventional motor, and (b) is a rotor after the unequal pole arc width method of the permanent magnet is adopted;
fig. 3 is a schematic view of rotor magnetic poles of the rotor of motor embodiment 1 of the present invention installed with a 180 ° offset.
Fig. 4 is a comparison of cogging torque results for motor embodiment 1 of the present invention versus a conventional permanent magnet motor, a stator skewed slot motor, and a conventional pole segment motor;
fig. 5 is a comparison of the radial magnetic pull results of motor embodiment 1 of the present invention with conventional permanent magnet motors, stator skewed slot motors and conventional pole segmented motors, and a segment of rotor unequal pole width motors;
fig. 6 is a comparison of the axial magnetic pull results of embodiment 1 of the motor of the present invention with conventional permanent magnet motors, stator skewed slot motors, and conventional pole segmented motors;
fig. 7 is a comparison of no-load back emf results for motor embodiment 1 of the present invention versus a conventional permanent magnet motor, a stator skewed slot motor, and a conventional pole segment motor;
fig. 8 is a comparison of dynamic torque results for motor embodiment 1 of the present invention versus a conventional permanent magnet motor, a stator skewed slot motor, and a conventional pole segmented motor;
fig. 9 is a schematic structural view of an embodiment 2 of the motor of the present invention;
fig. 10 is an illustration of the unequal arc width form of permanent magnets according to embodiment 2 of the motor of the present invention, wherein (a) is a rotor of a conventional motor and (b) is a rotor after the unequal arc width method of permanent magnets is adopted;
fig. 11 is a schematic view of rotor magnetic poles of a rotor of motor embodiment 2 of the present invention installed with a 180 ° offset.
Fig. 12 is a comparison of cogging torque results for motor embodiment 2 of the present invention versus a conventional permanent magnet motor, a stator skewed slot motor, and a conventional pole segment motor;
fig. 13 is a comparison of the radial magnetic pull results for motor embodiment 2 of the present invention versus a conventional permanent magnet motor, a stator skewed slot motor and a conventional pole segmented motor, and a segment of a rotor motor with unequal pole widths;
fig. 14 is a comparison of the axial magnetic pull results for motor embodiment 2 of the present invention versus a conventional permanent magnet motor, a stator skewed slot motor, and a conventional pole segmented motor;
fig. 15 is a comparison of no-load back emf results for motor embodiment 2 of the present invention versus a conventional permanent magnet motor, a stator skewed slot motor, and a conventional pole segment motor;
fig. 16 is a comparison of dynamic torque results for motor embodiment 2 of the present invention versus a conventional permanent magnet motor, a stator skewed slot motor, and a conventional pole segmented motor;
in the figure, 1, a stator, 2, a stator yoke, 3, stator teeth, 4, an armature winding, 5, permanent magnets, 6, a rotor core, 7, a rotor shaft key groove, 8, rotor magnetic poles with unequal pole arc widths, 9, other rotor magnetic poles with the same pole arc width, 10, a first section of permanent magnet rotor in a segmented rotor, and 11, a second section of permanent magnet rotor in the segmented rotor.
The specific implementation mode is as follows:
the invention is further described with reference to the following figures and examples.
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, 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 invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
A rotor magnetic pole segmentation permanent magnet synchronous motor comprises a stator 1, permanent magnet rotors 10 and 11 and an armature winding 4, wherein each permanent magnet rotor comprises a rotor core 6 and a permanent magnet 5, the permanent magnet rotors are sleeved inside the stator and are arranged coaxially with the stator, and air gaps are formed between the stators and the rotors. The stator 1 comprises stator slots, stator teeth 3 and a stator yoke 2, and armature windings 4 are arranged in the stator slots.
The permanent magnet rotor is divided into two sections 10 and 11 along the axial direction, 2p permanent magnets 5 are placed on the surface of each section of the permanent magnet rotor, the width of a polar arc corresponding to one permanent magnet 8 in each permanent magnet 5 is different from the width of polar arcs corresponding to other permanent magnets 9, the width of polar arcs of the other 2p-1 permanent magnets 9 is the same, the width of the polar arc of each permanent magnet is determined through specific analytic calculation and electromagnetic calculation according to the size of an actual motor, and the permanent magnets can be radially magnetized and can also be parallelly magnetized.
The two sections of permanent magnet rotors 10 and 11 are staggered by 180 degrees in the axial direction, two key grooves 7 which are symmetrical up and down are arranged on the rotor shaft, so that the two sections of permanent magnet rotors 10 and 11 in processing and assembling can be conveniently and staggeredly installed, and the torque pulsation and the tooth harmonic current of the motor during operation can be effectively weakened through the novel rotor magnetic pole segmenting method, so that the electromagnetic vibration of the motor is greatly weakened. Meanwhile, the two sections of permanent magnet rotors 10 and 11 are staggered by 180 degrees along the axial direction, and flux linkages generated by permanent magnets on the rotors keep symmetry along the central line of the rotors, so that unbalanced radial magnetic tension caused by unequal magnetic pole widths of the rotors can be completely offset, and the electromagnetic vibration during the operation of the motor is further reduced.
By the rotor magnetic pole segmentation method, the cogging torque, the tooth harmonic electromotive force and the torque ripple of the surface-mounted permanent magnet motor can be greatly weakened, so that the electromagnetic vibration of the surface-mounted permanent magnet motor is effectively weakened.
The motor is greatly different from the traditional magnetic pole segmented motor, the traditional magnetic pole segmented motor generally divides the rotor into 2 to multiple segments and staggers a certain angle to achieve the effect of rotor oblique poles, the staggered angle is small, the process precision requirement is high, the motor divides the permanent magnet rotor into two segments, the two segments are staggered by 180 degrees, the staggered angle is large, and the implementation is easy. For the weakening effect of the cogging torque and the tooth harmonic current, the weakening degree of the traditional magnetic pole segmentation to the cogging torque is related to the number of segments of the rotor segmentation, and the cogging torque can not be weakened to 0 in theory; the motor and the method thereof avoid radial and axial unbalanced magnetic pull force generated by adopting the traditional skewed pole and skewed slot process, can keep the use amount of permanent magnet materials unchanged, and realize weakening of cogging torque and electromagnetic vibration of the motor under the condition of not reducing the effective magnetic flux of each pole of the motor.
Compared with a skewed pole or skewed slot method adopted in the traditional motor production process, the method has the advantages that the processing and assembling realization process is simple, the processing and assembling cost of the motor is greatly reduced, the actual engineering implementation is easy, and the control precision performance of the surface-mounted permanent magnet motor servo system is favorably improved. When the pole arc width of each permanent magnet is calculated, the pole arc width corresponding to the rotor magnetic poles with different widths may be larger than the pole arc widths of other 2p-1 magnetic poles, and may also be smaller than the pole arc widths of other 2p-1 magnetic poles.
Setting the width of the corresponding pole arc of the permanent magnets with different magnetic pole widths as thetaaThe other 2p-1 permanent magnets with the same magnetic pole width correspond to the pole arc width thetabThe width between poles between two adjacent magnetic poles is thetacAnd is provided with KtThe ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the pole arc widths of other magnetic poles is adopted, and the selection of the pole arc widths corresponding to each permanent magnet follows the following principle:
from analytical calculations, the expression for cogging torque can be expressed as:
Figure BDA0002373796480000111
when the rotor magnetic poles have unequal pole arc widths, B thereofrnThe Fourier expansion of (A) is:
Figure BDA0002373796480000112
in theory BrnWhen the torque is equal to 0, the value of the cogging torque is 0, and reasonable K is selectedtThe cogging torque of the permanent magnet motor can be effectively weakened, so the pole arc width theta corresponding to the permanent magnetaAnd thetabCan pass through BrnIn the expanded form of (K)tAnd the pole arc coefficient of the original motor. Taking the performance and the design principle of the motor into consideration, K is selectedtWhen, should choose the nearest 1 and let BrnK equal to 0tValue of thetaaAnd thetabThe difference value of (a) is minimum to ensure the reasonability of the motor design.
The width of the pole arc corresponding to the permanent magnet is changed, so that the number of the slots corresponding to each rotor magnetic pole is changed, wherein the number of the stator slots corresponding to the rotor magnetic poles formed by the permanent magnets with different pole arc widths is as follows:
Figure BDA0002373796480000113
the number of stator slots corresponding to the rotor magnetic poles formed by other 2p-1 permanent magnets with the same pole arc width is as follows:
Figure BDA0002373796480000121
due to KtThe number of the stator slots corresponding to each rotor magnetic pole of the motor is a fraction, the number of the stator slots occupied by each phase belt under each rotor magnetic pole is different, so that the phases of the tooth harmonic electromotive force induced by the conductors in the same phase in the stator slots are different, and when the tooth harmonic electromotive force vectors of the coils in the same phase are added, most of the tooth harmonic electromotive force is counteracted, so that the tooth harmonic electromotive force in the armature winding can be greatly weakened under the condition that the corresponding pole arc widths of the permanent magnet are different.
The following two embodiments can be specifically classified according to whether the pole arc width of the rotor magnetic pole with different widths is larger or smaller than the pole arc width of other 2p-1 rotor magnetic poles.
The first embodiment is as follows:
as shown in fig. 1 to 8, the number of poles of the motor of the present embodiment is 6, the number of stator slots is 36, the present embodiment includes a stator 1, permanent magnet rotors 10 and 11, and an armature winding 4, the permanent magnet rotors 10 and 11 comprise rotor iron cores 6 and permanent magnets 5, the stator 1 is provided with stator slots, the armature windings 4 are placed in the stator slots, the permanent magnet rotors 10 and 11 are concentrically arranged with the stator 1, the permanent magnet rotors are divided into two sections 10 and 11 along the axial direction, 6 permanent magnets 5 are placed on the surface of each section of the rotors, the width of the pole arc corresponding to one permanent magnet 8 in the 6 permanent magnets 5 is different from the width of the pole arc corresponding to the other permanent magnets 9, the width of the pole arc corresponding to the permanent magnet 8 in the embodiment is larger than the width of the pole arc corresponding to the other permanent magnets 9, the other 5 permanent magnets 9 have the same pole arc width, and the magnetic pole width of each permanent magnet 5 is determined by specific analytical calculation and electromagnetic calculation according to the size of the actual motor.
The two sections of permanent magnet rotors 10 and 11 are staggered by 180 degrees along the axial direction, and two key grooves 7 which are symmetrical up and down are arranged on the rotor shaft, so that the staggered installation of the two sections of permanent magnet rotors 10 and 11 in the process of processing and assembling is facilitated. The novel rotor magnetic pole segmentation method can effectively weaken torque pulsation and tooth harmonic current when the motor runs, and further greatly weaken electromagnetic vibration of the motor.
Meanwhile, the two sections of rotors 10 and 11 are staggered by 180 degrees along the axial direction, and flux linkages generated by the permanent magnets 5 on the rotors keep symmetry along the central line of the rotors, so that unbalanced radial magnetic tension caused by unequal magnetic pole widths of the rotors can be completely offset, and the electromagnetic vibration during the operation of the motor is further reduced. Fig. 4 shows a comparison of the cogging torque of the conventional straight slot motor, the stator skewed slot motor, the conventional magnetic pole segment motor and the motor of embodiment 1 of the present invention, and the motor of the present invention can greatly weaken the cogging torque to a degree superior to that of the skewed slot motor and the conventional magnetic pole segment motor.
Fig. 5 compares the radial magnetic pull of the conventional straight slot motor, the stator skewed slot motor, the conventional magnetic pole segmented motor, the rotor motor with different magnetic pole widths and the motor embodiment 1 of the present invention, and the motor of the present invention effectively eliminates the radial unbalanced magnetic pull caused by the asymmetric rotor magnetic poles by the method of segmenting and staggering the magnetic poles by 180 degrees.
Fig. 6 compares the axial magnetic pull force of the conventional straight slot motor, the stator skewed slot motor, the conventional magnetic pole segment motor and the motor embodiment 1 of the present invention, and compared with the skewed slot method commonly used in the industry, the motor of the present invention does not introduce additional axial force, which is beneficial to further reducing the electromagnetic vibration caused by the axial force.
Fig. 7 compares the idle-load back emf of the conventional straight slot motor, the stator skewed slot motor, the conventional pole segmented motor and the motor embodiment 1 of the present invention, and the motor of the present invention has a significant attenuation of the tooth harmonic emf to a degree comparable to the stator skewed slot method and the conventional pole segmented method.
Fig. 8 compares the dynamic torque of the conventional straight slot motor, the stator skewed slot motor, the conventional pole segment motor and the motor embodiment 1 of the present invention, and the torque ripple of the motor of the present invention is small, verifying the excellent effect of the motor of the present invention on the torque ripple attenuation.
Example two:
as shown in fig. 9-16, the number of poles of the motor of the present embodiment is 6, the number of stator slots is 36, the present embodiment includes a stator 1, permanent magnet rotors 10 and 11, and an armature winding 4, where the permanent magnet rotors 10 and 11 include a rotor core 6 and permanent magnets 5, the stator 1 is provided with stator slots, the armature winding 4 is placed in the stator slots, the permanent magnet rotors 10 and 11 are concentrically arranged with the stator 1, the permanent magnet rotors are divided into two segments 10 and 11 along an axial direction, and 6 permanent magnets 5 are placed on the surface of each segment of the rotor.
The width of the pole arc corresponding to one permanent magnet 8 in the 6 permanent magnets 5 is different from the width of the pole arc corresponding to the other permanent magnets 9. In this embodiment, the width of the pole arc corresponding to the permanent magnet 8 is smaller than the width of the pole arc corresponding to the other permanent magnets 9, the width of the pole arc of the other 5 permanent magnets 9 is the same, and the width of the magnetic pole of each permanent magnet 5 is determined by specific analytic calculation and electromagnetic calculation according to the size of the actual motor. The two sections of rotors 10 and 11 are staggered by 180 degrees along the axial direction, and two key grooves 7 which are symmetrical up and down are arranged on the rotor shaft, so that the staggered installation of the two sections of rotors 10 and 11 in the process of processing and assembling is facilitated.
The novel rotor magnetic pole segmentation method can effectively weaken torque pulsation and tooth harmonic current when the motor runs, and further greatly weaken electromagnetic vibration of the motor. Meanwhile, the two sections of rotors 10 and 11 are staggered by 180 degrees along the axial direction, and flux linkages generated by the permanent magnets 5 on the rotors keep symmetry along the central line of the rotors, so that unbalanced radial magnetic tension caused by unequal magnetic pole widths of the rotors can be completely offset, and the electromagnetic vibration during the operation of the motor is further reduced.
Fig. 12 shows a comparison between the cogging torque of the conventional straight slot motor, the conventional skewed slot motor, the conventional segmented pole motor, and the motor of the present invention in embodiment 2, which can greatly reduce the cogging torque, and the effect of reducing the cogging torque is substantially the same as that of the stator skewed slot motor and the conventional segmented pole motor.
Fig. 13 shows the radial magnetic pull of the conventional straight slot motor, stator skewed slot motor, conventional magnetic pole segmented motor, one-segment rotor motor with unequal magnetic pole widths, and the embodiment 2 of the motor of the present invention, which effectively eliminates the radial unbalanced magnetic pull caused by asymmetric rotor magnetic poles by means of magnetic pole segmentation and 180-degree stagger.
Fig. 14 compares the axial magnetic pull force of the conventional straight slot motor, the stator skewed slot motor, the conventional pole segment motor and the motor embodiment 2 of the present invention, and compared with the skewed slot method commonly used in the industry, the motor of the present invention does not introduce additional axial force, which is beneficial to further reducing the electromagnetic vibration caused by the axial force.
Fig. 15 compares the no-load back emf of the conventional straight slot motor, the stator skewed slot motor, the conventional pole segmented motor and the motor embodiment 2 of the present invention, which has a significant attenuation of the tooth harmonic emf to a degree comparable to the stator skewed slot method and the conventional pole segmented method.
Fig. 16 compares the dynamic torque of the conventional straight slot motor, the stator skewed slot motor, the conventional pole segment motor and the motor embodiment 2 of the present invention, and the torque ripple of the motor of the present invention is small, verifying the excellent effect of the motor of the present invention on the torque ripple attenuation.
The motor obtains a non-oblique-pole skewed slot, and under the condition of the same permanent magnet material dosage, the torque pulsation and the electromagnetic vibration suppression which change the corresponding pole arc width of the permanent magnet on the rotor are suppressed.
The motor provided by the invention can be used in many ways, and the following are simply exemplified:
(1) household appliances: including television audio and video equipment, fans, air-conditioning external hanging machines, food processing machines, smoke exhaust ventilators and the like.
(2) Computer and its peripheral equipment: including computers (drives, fans, etc.), printers, plotters, optical drives, optical disc recorders, scanners, etc.
(3) Industrial production: including industrial drives, material processing systems, automation equipment, robots, transmission systems, and the like.
(4) The automobile industry: the system comprises a permanent magnet starter, a windscreen wiper motor, a door lock motor, a seat lifting motor, a sunshade ceiling motor, a cleaning pump motor, a motor for a recorder, a glass lifting motor, a radiator cooling fan motor, an air conditioner motor, an antenna lifting motor, an oil pump motor, a rearview mirror adjustment and the like.
(5) The field of public life: including clocks, beauty machines, vending machines, cash dispensers, cash registers, etc.
(6) The field of transportation: including trolleybuses, aircraft accessories, ships, and the like.
(7) The aerospace field: including rockets, satellites, spacecraft, space shuttles, and the like.
(8) The national defense field: including tanks, missiles, submarines, planes, etc.
(9) The medical field is as follows: including dental burs, artificial hearts, medical instruments, and the like.
(10) The field of power generation: the system comprises a generator for wind power generation, waste heat power generation, small hydroelectric power generation, a small internal combustion generator set, an auxiliary exciter of a large generator and the like.
(11) The field of servo control.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.

Claims (8)

1. A rotor magnetic pole segmentation permanent magnet synchronous motor is characterized in that: the permanent magnet motor comprises a stator, a permanent magnet rotor and an armature winding, wherein the permanent magnet rotor comprises a rotor core and a permanent magnet, the permanent magnet rotor is sleeved in the stator and is coaxially arranged with the stator, and the armature winding is arranged on the stator;
the permanent magnet rotor is divided into two sections along the axial direction, the two sections of permanent magnet rotors are completely identical in structure and are installed in a staggered mode along the axial direction, 2p permanent magnets are placed on the surface of each section of rotor, p is the number of pole pairs of the motor, the width of a pole arc corresponding to one permanent magnet in the permanent magnets is different from the width of pole arcs corresponding to other permanent magnets, and the width of pole arcs of the other 2p-1 permanent magnets is identical;
the two sections of permanent magnet rotors are staggered by 180 degrees along the axial direction when being installed, and two key grooves which are symmetrical up and down are arranged on the rotor shaft;
the rotor magnetic poles with unequal pole arc widths in the two sections of rotors are symmetrically distributed along the center of the rotor, and the magnetic flux of the whole rotor is symmetrically distributed along the rotor.
2. The rotor pole segment permanent magnet synchronous motor of claim 1, wherein: the stator is provided with a plurality of stator slots, and the stator slots are of a straight slot structure.
3. The rotor pole segment permanent magnet synchronous motor of claim 1, wherein: the armature winding is placed in a stator groove, and the two sections of permanent magnet rotors and the stator are concentrically arranged.
4. The rotor pole segment permanent magnet synchronous motor of claim 1, wherein: the permanent magnets are magnetized radially or in parallel.
5. A method for weakening electromagnetic vibration of a rotor magnetic pole segmented permanent magnet synchronous motor is characterized by comprising the following steps: the method comprises the following steps: the permanent magnet rotor is divided into two sections along the axial direction, the two sections of permanent magnet rotors have the same structure and are installed in a staggered mode of 180 degrees along the axial direction, and two key grooves which are distributed up and down symmetrically are arranged on a rotor shaft; 2p permanent magnets are placed on the surface of each section of the rotor, wherein p is the number of pole pairs of the motor, the width of a pole arc corresponding to one permanent magnet in the permanent magnets is different from the width of pole arcs corresponding to other permanent magnets, and the width of the pole arcs of other 2p-1 permanent magnets is the same; the rotor magnetic poles with unequal pole arc widths in the two sections of rotors are symmetrically distributed along the center of the rotor, and the magnetic flux of the whole rotor is symmetrically distributed along the rotor.
6. The method for weakening the electromagnetic vibration of the rotor pole segment permanent magnet synchronous motor as claimed in claim 5, wherein the method comprises the following steps: provided with different magnetic pole widthsThe width of the pole arc corresponding to the permanent magnet is thetaaThe other 2p-1 permanent magnets with the same magnetic pole width correspond to the pole arc width thetabThe width between poles between two adjacent magnetic poles is thetacAnd is provided with KtThe ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the pole arc widths of other magnetic poles, the process of determining the pole arc width corresponding to each permanent magnet includes:
from analytical calculations, the expression for cogging torque is expressed as:
Figure FDA0003479232170000021
in the formula, LaIs the axial length, R, of the armature core1And R2Respectively, the outer radius of the armature and the inner radius of the stator yoke, n is an integer such that nz/2p is an integer, z is the number of stator teeth, mu0Is a vacuum magnetic conductivity;
when the rotor magnetic poles have unequal pole arc widths, B thereofrnThe Fourier expansion of (A) is:
Figure FDA0003479232170000031
in the formula, KtIs the ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the other magnetic poles, p is the pole pair number, thetacThe inter-pole width between two magnetic poles;
the width theta of the pole arc corresponding to the permanent magnetaAnd thetabBy BrnIn the expanded form of (K)tSelecting K and determining the pole arc coefficient of the original motor according to the performance and design principle of the motortWhen, should choose the nearest 1 and let BrnK equal to 0tValue of thetaaAnd thetabThe difference of (a) is minimal.
7. The method for weakening the electromagnetic vibration of the rotor pole segment permanent magnet synchronous motor as claimed in claim 5, wherein the method comprises the following steps: the number of stator slots corresponding to the rotor magnetic poles formed by the permanent magnets with different pole arc widths is as follows:
Figure FDA0003479232170000032
wherein Z is the number of stator teeth, p is the number of pole pairs, KtThe ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the other magnetic poles.
8. The method for weakening the electromagnetic vibration of the rotor pole segment permanent magnet synchronous motor as claimed in claim 5, wherein the method comprises the following steps: the number of stator slots corresponding to rotor magnetic poles formed by 2p-1 permanent magnets with the same pole arc width is as follows:
Figure FDA0003479232170000033
wherein Z is the number of stator teeth, p is the number of pole pairs, KtThe ratio of the pole arc widths of the rotor magnetic poles with different pole arc widths to the other magnetic poles.
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Citations (3)

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Publication number Priority date Publication date Assignee Title
JPH0823664A (en) * 1994-05-02 1996-01-23 Aisin Aw Co Ltd Motor
CN105529852A (en) * 2016-02-23 2016-04-27 珠海格力节能环保制冷技术研究中心有限公司 Built-in permanent magnet motor rotor structure and motor with same
CN105958691A (en) * 2016-06-27 2016-09-21 伊泽瑞尔(大连)科技有限公司 Segmented inclined-pole rotor and motor comprising same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0823664A (en) * 1994-05-02 1996-01-23 Aisin Aw Co Ltd Motor
CN105529852A (en) * 2016-02-23 2016-04-27 珠海格力节能环保制冷技术研究中心有限公司 Built-in permanent magnet motor rotor structure and motor with same
CN105958691A (en) * 2016-06-27 2016-09-21 伊泽瑞尔(大连)科技有限公司 Segmented inclined-pole rotor and motor comprising same

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