CN1747281A - Sheet permanent-magnetic electric machine with bearing and its control - Google Patents

Abstract

The invention includes base, case, rotator, machine winding, suspension winding, core axle, bias permanent magnet, bracket of electric vortex sensor, stator bias yoke, rotator bias yoke, permanent bias magnet yoke and bracket system of sensor. The rotator adopts flaky texture to control suspension in two degree of freedom along radial direction so that the rotator can suspends steadily in five degree of freedom. One bias permanent magnet is used to supply bias magnetic flux and control suspension force by controlling current in suspension winding. The rotating excitation is provided by the permanent magnetic paster.

Description

Sheet permanent-magnetic electric machine with bearing and control method

One, technical field

The invention belongs to a kind of motor, particularly a kind of sheet permanent-magnetic electric machine with bearing.

Two, background technology

So-called bearing-free motor is exactly around 2 groups of coils on motor stator, one group is torque coil, is used to drive the rotor rotation, and another group is the magnetic suspension coil, be used to produce axial magnetic power supporting rotor, in fact be exactly the New-type electric machine that magnetic suspension bearing and motor are integrated.Traditional bearing-free motor system generally need two bearing-free motors and axial magnetic suspension bearing or bearing-free motor, one radially constitute with an axial magnetic suspension bearing, its deficiency is that volume is very big, dynamic property is lower.When the axial length of bearing-free motor rotor is compared with its diameter when very little, rotor axially is being a passive stabilization, stable suspersion only need be controlled two of the rotor radially degrees of freedom, and this special bearing-free motor is called as the sheet bearing-free motor, has that volume is little, the dynamic property advantages of higher.

Because the shared cover stator of the magnetic suspension winding of bearing-free motor and motor windings certainly exists coupling between them.In order to realize the decoupling zero control between torque and the magnetic suspension force, vector control technology and air gap field orientation technology are introduced in the control of common bearing-free motor in succession.But, do not solve coupled problem fully.Single bearing-free motor generally can only retrain rotor two degrees of freedom radially, realize that rotor stability suspends, need 2 bearing-free motors and an axial magnetic suspension bearing, perhaps need a bearing-free motor and one radially to add an axial magnetic suspension bearing again.Like this, common bearing-free motor not only is subjected to many restrictions mutually on control strategy, and structure is very complicated.

Three, summary of the invention

The object of the present invention is to provide that a kind of volume is little, simple in structure, cost is low and it is contactless to satisfy, do not have wearing and tearing, pollution-free, bearing-free motor that high efficiency requires.

Purpose of the present invention can reach by following measure:

At first, this rotor adopts laminated structure (that is: the rotor radial size is far longer than axial dimension), thereby makes motor axially and on the torsional direction realizing driven suspension, has removed axial magnetic bearing, has dwindled the volume of motor greatly; And when the motor number of pole-pairs satisfied M 〉=3, lotus root was separated in radial load and torque fully, can separately control, and has simplified control system.

Secondly, motor windings of the present invention adopts four pairs of electrode structures to pass to three-phase alternating current, and suspending windings adopts and passes to direct current, thereby makes the suspending power of motor and torque separate lotus root automatically, has simplified the control system of motor greatly.

Sheet permanent-magnetic electric machine with bearing of the present invention, comprise the housing that places on the base, the housing upper end links to each other with end cap, stator is fixed on the biasing yoke that places in the housing, be wound with motor windings and suspending windings in the stator slot, place in the stator its external peripheral surface of ring-type rotor that is installed in the mandrel stage casing by rotor biasing yoke to post permanent magnet coating symmetrically, the current vortex sensor that links to each other with control system is fixed on the mandrel epimere by sensor stand, place the permanent magnet bias yoke in base inner face and the housing to be installed in the mandrel hypomere, between this biasing yoke and rotor biasing yoke, place the biasing permanent magnet.Current vortex sensor of the present invention detects the radial displacement that the transducer retaining ring is a ring in the rotor (also can by the displacement of another kind of structure detection ring-type rotor exterior ring), displacement signal changes voltage signal into by the transducer treatment circuit, voltage signal is sent into power amplifier after by the PID processing of circuit, power amplifier is converted into corresponding current signal with the voltage signal that is received and sends into suspending windings, thus the radial suspension of control motor.

Because this rotor adopts laminated structure, if the control motor radially the suspension of two degrees of freedom just can realize the stable suspersion of five degrees of freedom of rotor space, simplified the control system of motor greatly, dwindled motor volume; This motor provides the biasing magnetic flux of suspension with a biasing permanent magnet, controls magnetic suspension force by the electric current of controlling in this motor suspending windings, thereby realizes the radial suspension of motor, therefore belongs to hybrid bearing-free motor; This motor rotating excitation is provided by the permanent magnet coating of rotor surface, and therefore the control and the permagnetic synchronous motor of rotation are similar.When the motor number of pole-pairs satisfies M 〉=3, suspend and the control of rotation is separate.Therefore, the present invention has following advantage:

1, volume is little, simple in structure, novel in design rationally, control system is simple, can be operated in contactless, pollution-free, friction free magnetic suspension state.

2, durable reliable, can move and Maintenance free for a long time, more need not change parts.Particularly to some Medical Instruments and need the instrument of continuous operation, application advantage is particularly outstanding.

Four, description of drawings

Fig. 1 is a profile of the present invention;

Fig. 2 is a suspending windings schematic diagram of the present invention;

Fig. 3 is a permanent magnet coating structural representation of the present invention; Wherein figure (a) is four permanent magnet coating excitations that magnetize in the same way; Figure (b) is eight forward and reverse permanent magnet coating excitations that magnetize; Figure (c) is four rhombus permanent magnet coating excitations that magnetize in the same way.

Fig. 4 is a rotor passive stabilization schematic diagram of the present invention;

Fig. 5 is a radial suspension magnetic circuit schematic diagram of the present invention.

Among Fig. 1: 1 base, 2 housings, 3 end caps, 4,5,6 biasing yokes, 7 stators, 8 rotor assembly, 9 sensor stand assemblies, 10 mandrels, 11 windings, 12 biasing permanent magnets, 13 permanent magnet coatings, 14 transducer retaining rings

Among Fig. 5: dotted line is the control magnetic flux that suspending windings produces, the biasing magnetic flux that solid line produces for the biasing permanent magnet.

Five, embodiment

As shown in Figure 1, the concrete composition of sheet permanent-magnetic electric machine with bearing of the present invention is, place housing 2 its upper ends on the base 1 to link to each other with end cap 3, stator 7 is fixed on the biasing yoke 5 that places in the housing 2, stator 7 has groove, in groove, be wound with motor windings and suspending windings 11, ring-type rotor 8 places in the stator and is installed in mandrel 10 stage casings by rotor biasing yoke 6, ring-type rotor 8 external peripheral surfaces post permanent magnet coating 13 symmetrically, the current vortex sensor that links to each other with control system is fixed on mandrel 10 epimeres by sensor stand 9, place the permanent magnet bias yoke 4 in base 1 inner face and the housing 2 to be installed in mandrel 10 hypomeres, between permanent magnet bias yoke 4 and rotor biasing yoke 6, place biasing permanent magnet 12.Wherein the stator in the accompanying drawing 17 is overrided to form by electrical steel sheet, and leaves the groove of some, puts into the motor windings of 8 utmost points and the suspending windings 11 of 2 utmost points, and motor windings passes to alternating current, and suspending windings passes to direct current.The outlet of winding 11 is drawn by the through hole on the base 1.Four current vortex sensors are fixing by sensor stand 9 and mandrel 10, thereby current vortex sensor is by the interior ring radial displacement of the radial displacement detection rotor assembly 8 of detecting sensor retaining ring 14, also can adopt sensor rotor assembly 8 external loop diameters to suspend to displacement mode control rotor radial, the outlet of last transducer is drawn by the through hole on mandrel 10 and the base 1.

With the stator center is initial point, sets up the xyz rectangular coordinate system, and x direction and y direction respectively have a cover magnetic suspension winding to control axial magnetic power on this both direction respectively on the stator, thus the radial position of control rotor.Distribute in order to make suspending windings produce near sinusoidal magnetic flux density in air gap, former suspending windings adopts and strides the tooth method for winding, and its shortcoming is that operation easier is very big.Suspending windings of the present invention adopts monodentate winding mode as shown in Figure 2, constitutes monodentate suspending windings version, the T shown in the accompanying drawing 2 ₁, T ₂And T ₃Be the coil turn of y direction magnetic suspension winding of the present invention on the different teeth.Promptly on three adjacent teeth independently of one another respectively coiling suspending windings (T3), (T2+T3) and (T1+T2+T3) wherein T1, T2, T3 satisfy following rule:

${\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="A20051004154100071.png,A20051004154100081.png"\; state="\{\{state\}\}">T</figure-callout>}}_1=\frac{T_{\mathrm{all}}}{2}(1-\cos \left(\frac{\mathrm{\&pi;}}{6}\right))$ ${\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="A20051004154100071.png,A20051004154100081.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=\frac{T_{\mathrm{all}}}{2}(\cos \left(\frac{\mathrm{\&pi;}}{6}\right)-\cos \left(\frac{\mathrm{\&pi;}}{3}\right))$ ${\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="A20051004154100071.png"\; state="\{\{state\}\}">T</figure-callout>}}_3=\frac{T_{\mathrm{all}}}{2}\cos \left(\frac{\mathrm{\&pi;}}{3}\right),$ T in the formula _AllFor the suspending windings total number of turns on the one degree of freedom promptly: T _All=2 (T ₁+ T ₂₁+ T ₃), it is identical with total bundle number of striding the tooth winding to guarantee that coil on each tooth is always pricked number, and experiment shows that it is approximately uniform that magnetic flux density that the monodentate winding method produces distributes with striding the tooth winding in air gap, but has obviously reduced labour intensity.Therefore the magnetic flux density of selecting suitable number of turn ratio, y direction magnetic suspension winding just can form near sinusoidal in air gap distributes.The suspension magnetic flux density that in like manner can produce the similar sine of x direction distributes.

Accompanying drawing 3 sticks structural representation behind the permanent magnet coating, wherein y for the permanent magnet coating 13 of rotor surface NdFeB material and rotor ₁(x), y ₂(x) be the structure function of permanent magnet coating.What figure (a) adopted is the permanent magnet coating excitation that four homophases magnetize; Figure (b) adopts eight permanent magnet coating excitations, and adjacent permanent magnet coating magnetizing direction is opposite; What figure (c) adopted is the rhombus permanent magnet coating excitation that four homophases magnetize.

The version that original permanent magnet coating adopts each permanent magnet coating two ends shown in the accompanying drawing 3 (c) to be separated from each other, in order further to improve the dynamic property of sheet permanent-magnetic electric machine with bearing, reduce loss and harmful additional torque of motor, the present invention adopts as accompanying drawing 3 (a), (b) four shown in are magnetized or eight permanent magnet coating versions that forward and reverse each permanent magnet coating two ends of magnetizing contact each other in the same way, it is very approaching sinusoidal that its magnetic flux density that produces in air gap is distributed, and greatly reduces the loss of motor, improved efficiency of motor, reduce the pulsation of motor output torque.

Accompanying drawing 4 is a ring-type rotor assembly 8 in axial passive stabilization principle schematic, when rotor when axial or torsional direction have any skew, all can be subjected to reciprocal magnetic pull and make its homing.Accompanying drawing 5 is rotor radial suspension theory figure, and the present invention adopts the biasing permanent magnet that the needed biasing magnetic flux that suspends is provided, and realizes the rotor radial stable suspersion by the electric current of control suspending windings.Solid line is the biasing magnetic flux that permanent magnet produced among the figure, dotted line is the control magnetic flux that suspending windings produced, when the dotted line direction for as shown in Figure 5 left the time, the half of air-gap flux in a motor left side obviously increases, right half of air-gap flux obviously reduces, thereby the electromagnetic force that produces left makes rotor to left avertence.Therefore control the sense of current and the size of suspending windings, just can control the direction and the size of suspension magnetic flux, finally control the radial displacement of rotor, realize the rotor radial stable suspersion.

Claims (5)

1., a kind of sheet permanent-magnetic electric machine with bearing, it is characterized in that: place the housing (2) on the base (1), its upper end links to each other with end cap (3), stator (7) is fixed on and places on the yoke (5) of setovering in the housing (2), stator (7) has groove, be wound with motor windings and suspending windings (11) in the groove, ring-type rotor (8) places in the stator and is installed in mandrel (10) stage casing by rotor biasing yoke (6), ring-type rotor (8) external peripheral surface posts permanent magnet coating, the current vortex sensor that links to each other with control system is fixed on mandrel (10) epimere by sensor stand (9), place the permanent magnet bias yoke (4) in base (1) inner face and the housing (2) to be installed in mandrel (10) hypomere, biasing permanent magnet (12) is installed between permanent magnet bias yoke (4) and rotor biasing yoke (6).

2, sheet permanent-magnetic electric machine with bearing according to claim 1 is characterized in that: this rotor adopts laminated structure, and promptly the rotor radial diameter is far longer than rotor axial length, and permanent magnet adopts the surface-type rotor magnetic circuit structural.

3, sheet permanent-magnetic electric machine with bearing according to claim 1 is characterized in that: this motor rotating excitation permanent magnet coating adopts four to magnetize in the same way or eight forward and reverse magnetizing and each permanent magnet coating two ends contacting structure form each other.

4, sheet permanent-magnetic electric machine with bearing according to claim 1 is characterized in that, suspending windings is a monodentate winding structure form, i.e. difference coiling suspending windings (T3), suspending windings (T2+T3) and suspending windings (T1+T2+T3) on three adjacent teeth.

5, a kind of control method of sheet permanent-magnetic electric machine with bearing is characterized in that, the motor windings of four pairs of electrode structures passes to three-phase alternating current, and suspending windings passes to direct current, and that realizes motor suspending power and torque separates lotus root automatically; The rotor of laminated structure detects the rotor radial displacement by current vortex sensor, displacement signal changes voltage signal into by the transducer treatment circuit, voltage signal enters power amplifier after by the PID processing of circuit, power amplifier is converted into corresponding current signal with the voltage signal that is received and sends into suspending windings, thus the radial suspension of control motor.

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