CN104184236B - Permanent magnet and the method for designing of this permanent magnet thereof for motor - Google Patents

Abstract

A kind of permanent magnet for motor, described motor includes rotor and motor stator, air gap is formed between described rotor and motor stator, it is characterised in that: described permanent magnet includes basal surface, and this basal surface fits with the outer surface of described rotor；Upper end face, on this, end face is relative with described air gap and set, and the contour line of described upper end face is sinusoidal wave and the curve of triple-frequency harmonics function superposition, and the function that the concrete shape of this curve is represented by equation below determines:It is an advantage of the current invention that: add optimum triple-frequency harmonics function by a sine and obtain new magnet structure, on the premise of the torque pulsation not increasing motor, adding torque output, motor has the advantages such as power density smooth movement high, energy-efficient, noise are low.

Description

Permanent magnet and the method for designing of this permanent magnet thereof for motor

Technical field

The present invention relates to a kind of permanent magnet, the permanent magnet of a kind of mounted magneto for face and this permanent magnet thereof Method for designing.

Background technology

The rotor of existing mounted magneto generally could be used without through cutting the permanent magnet that pole processes, as it is shown in figure 1, The outer cross section of the permanent magnet of this motor is cylinder, this permanent magnet the Gas-gap Magnetic Field Resonance Wave content produced is high, thus causes The cogging torque of motor is big and runs the pulsation of torque greatly, produces bigger vibration and noise, affects the control of whole set equipment Precision and positioning precision.

In order to reduce the cogging torque of motor and run torque pulsation, the control accuracy of raising equipment, in the prior art, The Chinese invention patent " permanent magnet motor and the permanent magnet for motor " of existing Application No. 201080013643.X Disclosing a kind of motor with PM rotor and a kind of permanent magnet, in described motor, permanent magnet is assembled in cylinder On the outer surface of shape rotor, the permanent magnet forming rotor magnetic pole is shaped as the middle part at magnetic pole of the air gap so that motor Substantially the most constant, and described air gap when moving towards pole edge by substantially straight line forward in the way of increase, Permanent magnet has uniform thickness at middle part, and attenuates towards edge.

The motor of above-mentioned patent is by changing the shape of conventional permanent magnet, and its permanent magnet is shaped as existing so that the air gap of motor The zone line of magnetic pole is substantially constant, when moving to the edge of magnetic pole from the zone line of magnetic pole described air gap with Substantially straight line mode forward increases, and the width that described zone line is in rotor tangential direction is magnet width At least half.The permanent magnet shape of this patent reduces moment ripple and the profile of tooth moment of motor, but cannot well control The average torque of motor processed, it is the same that this realizes permanent magnet with the method using SIN function processing at present, as in figure 2 it is shown, Although the method can reduce the cogging torque of motor and run torque pulsation, but also reduce the average of motor simultaneously and turn Square, and then reduce the torque density of motor, operational efficiency.Therefore, how to turn at the cogging torque and operation reducing motor On the premise of square pulsation, it is ensured that the average torque of motor and operational efficiency are that urgently to be resolved hurrily one of the mounted magneto in face asks Topic, needs to make further improvement.

Summary of the invention

First to be solved by this invention technical problem is that and provide the defeated of a kind of motor for above-mentioned prior art present situation Go out the permanent magnet of the mounted magneto in face that efficiency is high and output torque pulsation is little.

Second technical problem to be solved by this invention is to provide the permanent magnet of a kind of above-mentioned mounted magneto Method for designing.

The present invention solves the technical scheme that above-mentioned first technical problem used: a kind of permanent magnet for motor, institute The motor stated includes rotor and motor stator, forms air gap, its feature between described rotor and motor stator It is: described permanent magnet includes

Basal surface, this basal surface fits with the outer surface of described rotor；

Upper end face, on this, end face is relative with described air gap and set, and the contour line of described upper end face is sinusoidal wave and triple-frequency harmonics The curve of function superposition, the function that the concrete shape of this curve is represented by equation below (I) determines:

$\left\{\begin{array}{c}{\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)={\mathrm{\Δm}}_a[\sin \left(\mathrm{p\θ}\right)+a\sin \left(3\mathrm{p\θ}\right)]\\ {\mathrm{\Δm}}_a=\frac{1}{8a}{\left(\frac{1+3a}{12a}\right)}^{-\frac{3}{2}}\end{array}\right.---\left(I\right)$

Wherein, above-mentioned public formula (I) uses polar coordinate system, the Δ h in public formula (I)_m(θ) it is the upper top surface profile of described permanent magnet The footpath, pole of any point M on line, θ is the polar angle of any point M on the upper top surface profile line of described permanent magnet；P is motor Number of pole-pairs；A is the amplitude of triple-frequency harmonics function；Δm_aIt it is the value changed with amplitude a of triple-frequency harmonics function.

The present invention solves the technical scheme that above-mentioned second technical problem used: the method for designing of a kind of permanent magnet, its It is characterised by: described method for designing comprises the following steps that

(1) basal surface, setting described permanent magnet is shaped as the arc surface that the outer surface with rotor is fitted, this circular arc The radius size in face is determined by the radius size of described rotor；

(2), setting amplitude a=1/6 of described triple-frequency harmonics function, the upper end face curve shape of described permanent magnet is by following public The function representation of formula (II):

${\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)=\frac{2\sqrt{3}}{3}[\sin \left(\mathrm{p\θ}\right)+\frac{1}{6}\sin \left(3\mathrm{p\θ}\right)]---\left(\mathrm{II}\right)$

(3), the curve that the function in described public formula (II) is formed is substituted by three sections of camber lines being sequentially connected with, described three sections of arcs Line is respectively left half arc, top arc and right half arc, the most left half arc and right half arc for being symmetrical arranged；

(4), the curve peak Δ h that the function in described public formula (II) is formed is set_m(θ)_maxWith the level representing motor gas-gap The tangent point of line is P1, sets the curve minimum point Δ h that the function in described public formula (II) is formed_m(θ)_minFor P2；

(5), described top arc is by with the maximum radius of described permanent magnet as radius and respectively through drawn by described some P1, some P2 Circular arc determine；

(6), described left half arc is by respectively through described some P1, P2 and the circular arc tangent with the horizontal line of described motor gas-gap Determining, described right half arc is symmetrical arranged with described left half arc and arc radius is equal；

(7), described left half arc, top arc and right half arc be sequentially connected with, the camber line formed is the upper top of described permanent magnet Facial contour curve.

Curved face processing for convenience, as preferably, described left half arc, between top arc and right half arc for the connection that smoothly transits.

Compared with prior art, it is an advantage of the current invention that: add optimum triple-frequency harmonics function by a sine and obtain new Magnet structure, the magnetic field harmonics produced due to this permanent magnet only adds triple-frequency harmonics, but for Y-connection winding Its tertiary current does not exists, thus on the premise of the torque pulsation not increasing motor, adds torque output, and make It is low etc. that the mounted magneto in face using this permanent magnet shape has power density smooth movement high, energy-efficient, noise Advantage.

Accompanying drawing explanation

Fig. 1 is one of conventional permanent magnet structural representation of the prior art (rectangle).

Fig. 2 is two (sinusoidal wave) of conventional permanent magnet structural representation of the prior art.

Fig. 3 is the motor general assembly drawing of the embodiment of the present invention.

Fig. 4 is the motor rotor construction schematic diagram shown in Fig. 3.

Fig. 5 is the magnet structure schematic diagram of embodiment of the present invention rotor.

Fig. 6 is the schematic diagram that the permanent magnet external surface shape of the embodiment of the present invention changes with polar angle.

Fig. 7 is the schematic diagram that the permanent magnet torque of the embodiment of the present invention changes with triple-frequency harmonics amplitude.

Fig. 8 is the magnet structure schematic diagram of the syllogic processing method realization of the embodiment of the present invention.

The comparison diagram that Fig. 9 is the motor of the present embodiment permanent magnet and the cogging torque of existing motor changes with rotor-position.

The comparison diagram that Figure 10 is the motor of the present embodiment permanent magnet and the torque of existing motor changes with rotor-position.

Detailed description of the invention

The present invention is described in further detail by lower combination accompanying drawing embodiment.

As shown in Fig. 3～Fig. 7, the present embodiment relates to the method for designing of a kind of permanent magnet and this permanent magnet, the present embodiment Permanent magnet is used for surface stuck type motor, is illustrated in figure 3 the general assembly drawing of this motor, and motor is by motor stator 1 and rotor 2 compositions, permanent magnet 3 is fixed on the surface of rotor 2 by High-strength glue.

The distribution of air-gap field during motor work is closely related with the shape of permanent magnet, and traditional permanent magnet 3 ' is usually Rectangular configuration as shown in Figure 1, the magnetic field harmonics content of the square-wave profile produced during the work of this permanent magnet 3 ' is high, thus leads The cogging torque sending a telegraph machine and the pulsation running torque are big；Permanent magnet 3 shown in Fig. 2 " have employed the sinusoidal wave magnetic being distributed , although its amplitude size is identical with square wave field, but fundamental voltage amplitude reduces, thus reduces the torque density of motor, Reduce overall efficiency.

Sine wave and triple-frequency harmonics have been done superposition by the permanent magnet 3 of the present embodiment, it is thus achieved that have novel curved surface profile shape Magnet structure.The permanent magnet 3 of the present embodiment includes basal surface and upper end face, and wherein, basal surface is circular arc, should Basal surface fits with the outer surface of rotor；

Upper end face arcuately, the air gap formed between rotor and motor stator, on this, end face is relative with air gap and set, The contour line of upper end face is sinusoidal wave and the curve of triple-frequency harmonics function superposition, and the concrete shape of this curve is by following public The function that formula (I) represents determines, sees Fig. 5, Fig. 6:

$\left\{\begin{array}{c}{\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)={\mathrm{\Δm}}_a[\sin \left(\mathrm{p\θ}\right)+a\sin \left(3\mathrm{p\θ}\right)]\\ {\mathrm{\Δm}}_a=\frac{1}{8a}{\left(\frac{1+3a}{12a}\right)}^{-\frac{3}{2}}\end{array}\right.---\left(I\right)$

Above-mentioned public formula (I) uses polar coordinate system, the Δ h in public formula (I)_m(θ) be described permanent magnet 3 upper top surface profile line on The footpath, pole of any point M, θ is the polar angle of any point M on the upper top surface profile line of described permanent magnet 3；P is motor pole Logarithm；A is the amplitude of triple-frequency harmonics function；Δm_aIt it is the value changed with amplitude a of triple-frequency harmonics function.

Wherein, amplitude a of triple-frequency harmonics function is the numerical value of a change, as a=0, and the upper end face wheel of permanent magnet 3 Profile is the curve shown in Fig. 6 dotted line t1, and now, permanent magnet 3 shape can be by with the change of position pole coordinate parameter Formula Δ h_m(θ)=Δ msin (p θ) represents, Δ m is the maximum gauge (i.e. the height of curve peak) of permanent magnet 3；When During a=1/6, triple-frequency harmonics function is the curve shown in Fig. 6 dotted line t2, and now, permanent magnet 3 shape is sat with pole, position The change of mark parameter can be by formulaRepresent, it can be seen that when injecting three When subharmonic amplitude a is the first-harmonic of 1/6, the torque output maximum of motor, see Fig. 7.Dotted line t1 and dotted line t2 is respectively Representing SIN function and the curve of triple-frequency harmonics function, permanent magnet 3 true form of the present embodiment is i.e. folded by these two curves Add and obtain；Visible, the peak of the curve t1 that SIN function obtains is added triple-frequency harmonics function by SIN function and obtains 1.15 times of the peak of curve T.

But, the permanent magnet 3 obtained shown in Fig. 6 needs to add optimum triple-frequency harmonics function by a sine during fabrication and realizes, Its course of processing is complicated, and manufacturing cost is high.In order to simplify manufacture process, the present embodiment also proposed one and can substitute Stating permanent magnet and simplify the Design of Permanent Magnet method of the course of processing, see Fig. 8, this method for designing comprises the following steps that

(1), set permanent magnet basal surface be shaped as with rotor outer surface laminating arc surface, this arc surface Radius size is determined by the radius size of rotor；

(2), when setting amplitude a=1/6 of triple-frequency harmonics function,The now upper end face curve of permanent magnet Shape is by the function representation of equation below (II):

${\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)=\frac{2\sqrt{3}}{3}[\sin \left(\mathrm{p\θ}\right)+\frac{1}{6}\sin \left(3\mathrm{p\θ}\right)]---\left(\mathrm{II}\right)$

(3) curve, by the function in public formula (II) formed is substituted by three sections of camber lines being sequentially connected with, and three sections of camber lines are respectively Left half arc, top arc and right half arc, the most left half arc and right half arc are for being symmetrical arranged；

(4), the curve peak Δ h that the function in public formula (II) is formed is set_m(θ)_maxWith the horizontal line phase representing motor gas-gap The point cut is P1, sets the curve minimum point Δ h that the function in public formula (II) is formed_m(θ)_minFor P2；

(5), described top arc is by with the maximum radius of described permanent magnet as radius and respectively through drawn by described some P1, some P2 Circular arc determine；

(6), the radius of described left half arc is respectively by through described some P1, some P2 and the horizontal line phase with described motor gas-gap The circular arc cut determines, the radius of described right half arc is equal with the radius of described left half arc；

(7), left half arc, top arc and right half arc be sequentially connected with, the upper top surface profile that the camber line formed is permanent magnet is bent Line, and, left half arc, between top arc and right half arc for the connection that smoothly transits.

It will be seen that its contour curve of permanent magnet that above-mentioned method for designing obtains is formed by three sections of circular sliding slopes, and lead to The permanent magnet actual curve shape crossing public formula (II) acquisition is the structure that centre is the most recessed and two ends are protruding, due under centre Recessed amplitude is the least, and in the actual course of processing, middle lower concave part can approximate by with permanent magnet maximum radius as radius Circularity substitution, the curve of both sides is determined by the way of step (4) and step (6) by left half arc and right half arc the most respectively, this Just enormously simplify the course of processing, reduce difficulty of processing.

Fig. 9 show the cogging torque comparison diagram of the mounted magneto in face of different permanent magnet shape, and Figure 10 show not With the mounted magneto in the face of permanent magnet shape electromagnetic torque comparison diagram in the case of nominal load；Can from figure Go out, relative to traditional mounted magneto in face, permissible by adding the permanent magnet of triple-frequency harmonics functional based method design with sine Reducing torque pulsation, compare sine and cut the magneto of pole, the output of its average torque improves 11.5%, and torque pulsation Do not increase.On the other hand, the syllogic designed arc-shaped appearance method that the present embodiment uses obtains permanent magnet and is possible not only to reduce forever The difficulty of processing of magnet, and its average torque delivery efficiency with cut pole with the sine of standard and cut pole with triple-frequency harmonics and superpose and set The permanent magnet that meter obtains is compared and is also increased, and torque pulsation does not increase, therefore by syllogic designed arc-shaped appearance method The middle sine of place of equation (II) is cut pole and is cut the method for designing that pole superposes with triple-frequency harmonics and process the permanent magnet of the present embodiment The most feasible, also it is a kind of the most practical and efficient method.

Claims (1)

1., for a permanent magnet for motor, described motor includes rotor and motor stator, and described motor turns Air gap is formed between son and motor stator, it is characterised in that: described permanent magnet includes

Basal surface, this basal surface fits with the outer surface of described rotor；

Upper end face, on this, end face is relative with described air gap and set, and the contour line of described upper end face is sinusoidal wave and triple-frequency harmonics The curve of function superposition, the function that the concrete shape of this curve is represented by equation below determines:

$\left\{\begin{array}{c}{\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)={\mathrm{\Δm}}_a\[sin\left(p\mathrm{\θ}\right)+asin\left(3p\mathrm{\θ}\right)\]\\ {\mathrm{\Δm}}_a=\frac{1}{8a}{\left(\frac{1+3a}{12a}\right)}^{-\frac{3}{2}}\end{array}\right.---\left(I\right)$

Wherein, above-mentioned public formula (I) uses polar coordinate system, the Δ h in public formula (I)_m(θ) it is the upper top surface profile of described permanent magnet The footpath, pole of any point M on line, θ is the polar angle of any point M on the upper top surface profile line of described permanent magnet；P is motor Number of pole-pairs；A is the amplitude of triple-frequency harmonics function；Δm_aIt it is the value changed with amplitude a of triple-frequency harmonics function.