CN101170270A - Magnetic bearing plane permanent magnetic synchronization electromotor - Google Patents

Abstract

An in-plane permanent-magnet synchronous motor with magnetic suspension type bearings belongs to a magnetic suspension bearing type permanent-magnet synchronous motor. The motor comprises a rotor (2), motor stators (3, 6), a magnetic suspension bearing type stator (1), a transducer (5) and a transducer support (4). The two motor stators are respectively positioned axially on both sides of the rotor; the magnetic suspension bearing type stator is positioned radially outside the rotor; the magnetic field of the generated suspension force is distributed inside the radial plane of the rotor; the transducer support is positioned radially inside the rotor. The invention adopts an 8-pole symmetrical structure for radial magnetic suspension bearings; the suspension force in the two radial directions is separately controlled, so as to fulfill radial suspension of the motor. The motor rotor is in a sheet-shaped structure to control radial suspension with two degrees of freedom of the motor, so as to realize the stable suspension with five degrees of freedom in the rotor space. The invention simplifies a magnetic suspension structure control system and reduces the volume of the motor; therefore, having such unique advantages as simple control mechanism, low power consumption and no friction and etc, and having wide application foregrounds in the field of aerospace and aeroplane, mini-type rotary and high-speed machine, and energy and life sciences and etc.

Description

Magnetic bearing plane permanent magnetic synchronization electromotor

Technical field

The invention belongs to a kind of motor, particularly a kind of magnetic suspension bearing plane permanent magnetic synchronization electromotor.

Background technology

So-called plane permanent magnetic synchronization electromotor is exactly the axial both sides that stator is positioned at rotor, and air-gap field becomes a kind of motor of plane distribution vertically.1821, first motor in the world of faraday's invention was exactly plane permanent magnetic synchronization electromotor.Be limited to material and technological level at that time, plane permanent magnetic synchronization electromotor fails to be further developed.Yet people recognized some weakness that common cylinder formula motor exists gradually afterwards, and were low etc. as cooling difficulty and rotor core utilance.Rise the forties in last century, and plane permanent magnetic synchronization electromotor has been subjected to the attention of motor industry again.At present, developed the plane permanent magnetic synchronization electromotor of many variety classeses, different structure abroad.

Active Magnetic Suspending Bearing is to utilize magneticaction that rotor is suspended in the space, makes a kind of novel high-performance bearing of realizing not having machinery friction supporting between rotor and the stator.Magnetic bearing has unique advantages---and contactless, need not lubricate, there are not wearing and tearing, life-span is long, rigidity and damping are online adjustable, can adapt to various service conditionss, thus more and more attractive in the supporting field, and it has obtained increasingly extensive application in fields such as high-speed machine tool, steam turbine engine, air compressor, vacuum molecular pump, vibration isolator, accumulated energy flywheel, multidimensional platform, rate gyroscope and satellite antenna positioning.

If magnetic suspension bearing is combined with plane permanent magnetic synchronization electromotor, will bring a series of advantage.

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, magnetic bearing plane permanent magnetic synchronization electromotor that high efficiency requires.

Purpose of the present invention can reach by following measure:

At first, rotor of the present invention adopts the radially layered structure, and internal layer is a magnetic layer, and motor torque magnetic field is passed through wherein; Skin also is a magnetic layer, and radial suspension force magnetic field is passed through wherein; The centre is every magnetosphere, is used for separating two magnetic fields, and they are not intercoupled.

Secondly, motor stator of the present invention adopts six salient poles, and last coiling also passes to three-phase current, thereby produces the rotating magnetic field of one four utmost point in air gap.

The 3rd, magnetic bearing of the present invention partly adopts 8 utmost point symmetrical structures of common radial magnetic bearing, and its magnetic field distributes in the sagittal plane, and the control of the suspending power of directions X and Y direction is independently.

This motor comprises magnetic suspension bearing, rotor, motor stator, transducer, sensor stand, it is characterized in that, described magnetic suspension bearing is 8 utmost point symmetrical structures of radial magnetic bearing, is positioned at the radial outside of rotor; Described rotor is the flake structure of radial diameter greater than axial length, is made up of every magnetosphere clamping one cover between outer magnetic layer and internal layer magnetic layer and the inside and outside magnetic layer, and the upper and lower surface of rotor all is pasted with permanent magnet coating; Described motor stator is meant on the motor stator under the Stator and electrical machine, and upper and lower two motor stators place the upper and lower both sides of rotor axial respectively, equal coiling excitation winding on the salient pole of upper and lower two motor stators; Described transducer is installed on the sensor stand, is positioned at the radially inner side of rotor by sensor stand.

For simplified structure, the rotor of this motor adopts flaky texture (that is: the rotor radial size is far longer than axial dimension), as long as its radially suspension of two degrees of freedom of ACTIVE CONTROL, and on axial and torsional direction, realize driven suspension, thereby realize the stable suspersion of five degrees of freedom of rotor space, remove axial magnetic bearing, dwindled the volume of motor greatly, and simplified the control system of motor greatly.Therefore, magnetic bearing plane permanent magnetic synchronization electromotor of 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.

Description of drawings

Fig. 1 is a structure chart of the present invention;

Among Fig. 1: stator under stator, 4 sensor stands, 5 transducers, 6 motors on 1 magnetic suspension bearing, 2 rotors, 3 motors;

Fig. 2 is an electric machine structure expanded view of the present invention;

Fig. 3 is a magnetic bearing structure chart of the present invention;

Fig. 4 is a rotor structure figure of the present invention;

Among Fig. 4: 7 outer magnetic layers, 8 middle levels are every magnetosphere, 9 permanent magnet coatings, 10 internal layer magnetic layers;

Fig. 5 moves towards schematic diagram for radial suspension magnetic circuit of the present invention;

Fig. 6 is the driven suspension schematic diagram of rotor of the present invention; Wherein figure (a) for when rotor when axially skew being arranged, be subjected to reciprocal magnetic pull and the schematic diagram of homing; Figure (b) for when rotor when torsional direction has skew, be subjected to reciprocal magnetic pull and the schematic diagram of homing.

Embodiment

As shown in Figure 1, the main composition of magnetic bearing plane permanent magnetic synchronization electromotor of the present invention is: laminar rotor, two motor stators, magnetic suspension bearing stator and sensor stand (above lay four displacement transducers).

Accompanying drawing 2 has been set forth the electric machine structure and the magnetic circuit trend thereof of magnetic bearing plane permanent magnetic synchronization electromotor of the present invention, it has two motor stators as can be seen, be symmetrically distributed in the both sides of rotor, so formed air gap is a plane between them, magnetic direction is vertically.Respectively there are four plane permanent magnetic pasters on the upper and lower surface of rotor of the present invention, and arrange two N utmost points and two S utmost point spaces, and stator then has six salient poles, and last coiling also passes to three-phase current, thereby produces the rotating magnetic field of one four utmost point in air gap.The magnetic field that magnetic field that the permanent magnet coating of rotor surface of the present invention produces and stator winding produce can be regarded Sine distribution approx as, and they have excited magnetic force jointly, is motor torque and axial suction.

Can regard the magnetic field equivalence that forms by permanent magnet coating of rotor surface of the present invention by hot-wire coil as to produce that coil turn is N _f, size of current is i _fAnd N _f, i _fBig I obtain by following formula:

$N_f{i}_f=2P{H}_m{l}_m=2P\frac{B_m{l}_m}{{\mathrm{\μ}}_r{\mathrm{\μ}}_0}---\left(1\right)$

H wherein _mBe the magnetic field size of permanent magnet, B _mBe the induction level of permanent magnet, l _mBe the thickness of permanent magnet, μ ₀Be the magnetic permeability rate in the vacuum, μ _rBe the relative permeability of permanent magnet coating, P is the field pole logarithm.

The three-phase current of stator is transformed in the rotating coordinate system,, can obtains monolateral torque T through calculating _sWith axial suction F _sFinal expression formula:

$T_s=\frac{3{\mathrm{\μ}}_0\mathrm{\π}({R_0}^2-{R_i}^2)N_s{N}_f}{16\mathrm{Pg}}---\left(2\right)$

$F_s=\frac{{\mathrm{\μ}}_0\mathrm{\π}({R_0}^2-{R_i}^2)}{16P^2{g}^2}\·[{N_f}^2{i_f}^2+\frac{5}{2}{N}_f{N}_s{i}_f{i}_d+\frac{3}{2}{N_s}^2({i_d}^2+{i_q}^2)]---\left(3\right)$

N wherein _sBe the number of turn of every phase winding in the stator, R _i, R ₀Be the inside and outside radius of rotor, P is the field pole logarithm, and g is the size of monolateral magnetic field air gap, i _d, i _qSize for direct-axis current and friendship shaft current.

So total torque and axial force can be expressed as:

T _Always=T _On+ T _Down(4)

F _Always=F _On-F _Down(5)

T wherein _AlwaysBe two synthetic torques that motor stator produces rotor up and down, T _OnBe the torque that last motor stator produces rotor, T _DownBe the torque that following motor stator produces rotor, F _AlwaysBe two synthetic axial suction that motor stator produces rotor up and down, F _OnBe the axial suction that last motor stator produces rotor, F _DownBe the axial suction of following motor stator to the rotor generation.

This shows, by changing direct-axis current i _dCan change synthetic axial suction F _AlwaysSize, but can't have influence on synthetic torque T _AlwaysSize.Therefore, when radial direction magnetic bearing can't produce enough axial driven suspension power, can be by the synthetic axial suction F of control _AlwaysSize realize that axial active suspends.

Accompanying drawing 3 is axial magnetic bearing structure figure of the present invention, adopt 8 utmost point symmetrical structures of common radial magnetic bearing, its magnetic field distributes in the sagittal plane, and the control of the suspending power of directions X and Y direction is independently, finally can be expressed as:

F _y＝k _i·i _x+k _y·y (6)

Wherein: k _iBe electric current-force coefficient, k _yBe displacement-force coefficient, i _xBe magnetic suspension bearing winding current size, y is the rotor displacement amount.

As shown in Figure 4, do not intercouple in order to make motor torque magnetic field and radial suspension force magnetic field, rotor of the present invention must adopt the radially layered structure: internal layer is a magnetic layer, and motor torque magnetic field is in axial direction passed through wherein; Skin also is a magnetic layer, and the radial suspension force magnetic field radially direction on plane is passed through wherein, shown in the black line in the accompanying drawing 5; The centre is every magnetosphere, is used for separating two magnetic fields.

Accompanying drawing 6 is a laminar rotor of the present invention 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.

Claims (1)

1. magnetic suspension bearing plane permanent magnetic synchronization electromotor, comprise magnetic suspension bearing (1), rotor (2), motor stator (3,6), transducer (5), sensor stand (4), it is characterized in that, described magnetic suspension bearing (1) is 8 utmost point symmetrical structures of radial magnetic bearing, is positioned at the radial outside of rotor (2); Described rotor (2) is the flake structure of radial diameter greater than axial length, be made up of every magnetosphere (8) clamping one cover between outer magnetic layer (7) and internal layer magnetic layer (10) and the inside and outside magnetic layer (7,10), the upper and lower surface of rotor (2) all is pasted with permanent magnet coating (9); Described motor stator is meant stator (6) under stator on the motor (3) and the motor, and upper and lower two motor stators (3,6) place the upper and lower both sides of rotor axial respectively, equal coiling excitation winding on the salient pole of upper and lower two motor stators (3,6); Described transducer (5) is installed on the sensor stand (4), is positioned at the radially inner side of rotor (2) by sensor stand (4).

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