CN101697431B - Multi-gear fault-tolerance permanent magnetism magnetic flux switching electric machine and fault-tolerance method thereof - Google Patents

Abstract

The invention discloses a multi-gear fault-tolerance permanent magnetism magnetic flux switching electric machine and a fault-tolerance method thereof, belonging to a permanent magnetism fault-tolerance electric machine and a method. The electric machine comprises a salient pole stator, an armature winding and a salient pole rotor. Stator salient poles are E-shaped stator iron blocks; bar-shaped permanent magnets are embedded into a gap between every two E-shaped stator iron blocks in sequence; and stator windings which are coils from a first coil to a sixth coil are wounded on two E-shaped arms connected with the bar-shaped permanent magnets. Since the method employs the multitooth fault-tolerance permanent magnetism magnetic flux switching electric machine, the self inductance of the armature winding is increased; when the multi-gear fault-tolerance permanent magnetism magnetic flux switching electric machine uses high-coercive force permanent magnets, the short circuit current if can be restrained within the rated current iL without considerably increasing the number of turns of the armature winding. The invention has high reliability; the armature magnetic field makes small impact on the permanent magnets; the multi-gear structures of the stator and the rotor of the electric machine enable the electric machine to have small mutual inductance, strong magnetism isolating capability, big electrical inductance, strong capability of restraining the short circuit current and reduced location torque.

Description

Multiple tooth fault-tolerant permanent magnet flux switching motor and fault-tolerance approach thereof

Technical field

The present invention relates to a kind of fault-tolerant motor and method, relate in particular to a kind of multiple tooth fault-tolerant permanent magnet flux switching motor and fault-tolerance approach thereof, belong to the fault tolerant permanent magnet machine field.

Background technology

That starting/generator should have is simple in structure, reliable operation, efficient height, advantage such as safe in utilization.Type from starter-generator, there is not permanent magnet on the rotor, no winding, have simple in structure, firm, cost is low, reliable operation, control is flexible, operational efficiency is high, fault-tolerant ability is strong, have the adaptive switched reluctance machines of High Temperature And Velocity and have competitiveness, become the main research object of the U.S. from last century since the late nineteen eighties always in this field in this field.U.S. Kentucky university and GE, Sundstrand company have carried out a large amount of research and experiments to switch magnetic-resistance starting generator, developed the switch magnetic-resistance starting generator of 30kW, 250kW, 375kW, 500kW in succession, rotating speed is up to 48000 rev/mins.Domestic Nanjing Aero-Space University, Northwestern Polytechnical University have also developed low power principle prototype (being no more than 7.5kW) in succession at aviation aircraft.

Yet switched reluctance machines belongs to self-magnetized motor, and be half period work, the power density of motor and efficient await further raising, and its vibration and noise also are its intrinsic defectives, therefore the permanent-magnet type starter-generator of studying a kind of high efficiency, high power density, high fault-tolerant ability replaces the inevitable requirement that switch magnetic-resistance starting generator also is scientific and technological progress, also is the inexorable trend of this field development.

Magneto has suitable advantage aspect efficient, power density, the torque density, but its permanent magnet places on the rotor, high-power/as to exist during the operation of wide rotating speed such as the rotor protection and heat radiation, permanent magnet demagnetization, magnetic field are difficult to regulate and problem such as demagnetization difficulty during fault, cause classical at present permagnetic synchronous motor, brshless DC motor in starting/generating system is used, to be restricted.

Path has been opened up in the research that appears as novel starter-generator of stator permanent-magnet magneto.The stator permanent-magnet magneto mainly comprises doubly salient permanent magnet motor, flux switch motor, the anti-phase magneto of magnetic flux at present.This is wherein the highest with flux switch motor torque density and power density again.The summary of benefits of flux switch motor as: (1) permanent magnet places stator, be easy to the cooling, be not subjected to centrifugal force.(2) distinctive " poly-magnetic " effect makes motor also can obtain higher air gap flux density when adopting the lower permanent magnet of coercive force.(3) rotor structure is simple, is easy to high-speed cruising.(4) influenced by armature field little for permanent magnet, and when being short-circuited fault, the probability of permanent magnet generation irreversible demagnetization is minimum, and weak magnetic energy power is better than the rotor permanent-magnetic electric machine.(5) sine degree of back electromotive force is higher.(6) motor adopts centralized winding, and is simple in structure, and the end copper loss is little, the electric efficiency height.Above-mentioned superior function is that flux switch motor has been created condition in the application in starting-generating field.

From the angle of fault freedom, when switched reluctance machines one phase winding broke down, motor was with having certain fault-tolerance.But it torque ripple inevitably occurs, reduces its fault freedom.The Z.Q.Zhu professor of the Atkinson.D.J of Newscastle university, B.C.Mecrow professor and Shefield university, professor D.Howe then carry out the research of fault tolerant permanent magnet machine from the height of system's (being the system that motor and control combine together), and this motor at first is applied to aviation electrical actuation system.

The structure of fault tolerant permanent magnet machine is similar to general permanent magnetic brushless, but it is not a three phase electric machine, but polyphase machine, the notch number and the number of pole-pairs of stator are close, armature winding all is to adopt the mode of individual layer every the tooth coiling simultaneously, therefore fault tolerant permanent magnet machine also has the following advantages except the characteristics with general magneto: have the ability of heat isolation, magnetic isolation, electrical isolation between each phase winding, every phase winding has the short circuit current of inhibition ability.Yet at present at the fault-tolerant motor of rotor magneto still well do not solve such as rotor protection and heat radiation, permanent magnet demagnetization, magnetic field is regulated and problem such as demagnetization during fault.So, carried out apparent especially necessity of research of fault tolerant permanent magnet flux switch motor.

Isolate though realized heat isolation, electromagnetic isolation and the magnetic of motor stator winding every tooth excitation type flux switch motor, the self-induction L ratio of its unloaded permanent magnetism magnetic linkage φ and motor is bigger, i.e. short circuit current i _fBigger.Make short circuit current i _fLess than rated current, must reduce permanent magnet remanent magnetism greatly and increase umber of turn, cause the power density of motor and efficient lower.

Summary of the invention

The objective of the invention is defective at prior art, guarantee permanent magnet flux switching motor power density height, torque density height, (permanent magnet places stator to the inherent reliability height, good heat dissipation, be not subjected to centrifugal force) advantage under, the permanent magnet flux that self-induction L ratio is less, the magnetic isolating power is strong, location torque is little that proposes a kind of unloaded permanent magnetism magnetic linkage φ and motor switches fault-tolerant motor and fault-tolerance approach thereof.

Multiple tooth fault-tolerant permanent magnet flux switching motor comprises salient pole stator, armature winding, field spider, it is characterized in that:

Stator salient poles is an E type stator iron block, and the space between per two E type stator iron blocks embeds strip permanent magnet successively, twines i.e. first coil to the, six coils of stator winding on two E type arms that above-mentioned strip permanent magnet links to each other.

Described multiple tooth fault-tolerant permanent magnet flux switching motor is characterized in that: described E type stator iron block be " Y " type structure every the magnetic tooth, the stator number of teeth is 4 times of strip permanent magnet number; Rotor adopts multiple tooth structure, and its number of teeth can be 17 or 18 or 19.

The fault-tolerance approach of described multiple tooth fault-tolerant permanent magnet flux switching motor, it is characterized in that: adopt described multiple tooth fault-tolerant permanent magnet flux switching motor, reduce the mutual inductance between the adjacent windings and the location torque of described multiple tooth fault-tolerant permanent magnet flux switching motor, increased described armature winding self-induction, when described multiple tooth fault-tolerant permanent magnet flux switching motor when using the high-coercive force permanent magnet, need not to roll up the armature winding number of turn can be with short circuit current i _fBe suppressed at rated current i _LIn:

$i_f=\frac{\mathrm{\&phi;}}{\mathrm{NL}}<i_L=\frac{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="H2009101849471E00011.png"\; state="\{\{state\}\}">T</figure-callout>}}{\frac{3}{2}*{\mathrm{\&phi;}}_{\max }*N}---\left(1\right)$

Promptly make armature winding inductance and rated current i _LProduct more than or equal to the unloaded permanent magnetism magnetic linkage of armature winding, thereby improve the power density and the efficient of described multiple tooth fault-tolerant permanent magnet flux switching motor,

In the formula (1), φ represents the unloaded permanent magnet flux of coil, and N represents every circle coil turn, and L represents the inductance of single-turn circular coil, and T represents the nominal torque of motor, φ _MaxThe unloaded permanent magnet flux amplitude of representing every phase winding.

E type stator iron block be " Y " type structure every the magnetic tooth, increased magnetic circuit magnetic conductance every the magnetic tooth, reduced the mutual inductance of the armature winding adjacent windings of motor.

The present invention with compare every the fault-tolerant permanent magnet flux switching motor of tooth excitation type, when motor volume, draw ratio, the motor windings number of turn were consistent, the unloaded permanent magnetism magnetic linkage φ of multiple tooth fault-tolerant permanent magnet flux switching motor and the self-induction L ratio of motor reduced greatly, i.e. short circuit current i _fReduce greatly.Will be with short circuit current i _fBe suppressed at rated current i _LIn, the umber of turn that multiple tooth fault-tolerant permanent magnet flux switching motor increases is than lacking every the fault-tolerant permanent magnet flux switching motor of tooth excitation type, and so, the copper loss of motor is little, and it is high that efficient is wanted.The voltage that guarantees motor is certain, need further reduce permanent magnet coercive force every the fault-tolerant permanent magnet flux switching motor of tooth excitation type, thereby its power density, torque density reduce.

(permanent magnet places stator, is easy to cooling, is not subjected to centrifugal force making full use of permanent magnet flux switching motor inherent reliability height in the present invention; It is little that permanent magnet is influenced by armature field, when being short-circuited fault, the probability of permanent magnet generation irreversible demagnetization is minimum) the basis on, propose multiple tooth fault-tolerant permanent magnet flux switching motor, the self-induction L ratio of its unloaded permanent magnetism magnetic linkage φ and motor will be far smaller than every the fault-tolerant permanent magnet flux switching motor of tooth excitation type; The multiple tooth structure of the stator and rotor of motor makes that the motor mutual inductance is little, and the magnetic isolating power is strong, and the motor inductance is big, and it is strong to suppress the short circuit current ability, and the motor location torque reduces.This motor will have wide practical use to the higher field of starting-generating System Fault Tolerance performance near space aircraft, the how electric aircraft of full electricity etc.

Description of drawings

Fig. 1 is a structural section schematic diagram of the present invention.

The number in the figure title: 1, E type stator iron block, 2, field spider, 3, strip permanent magnet, first coil---the 6th coil is the concentrated armature coil of armature winding; Arrow among the figure on the strip permanent magnet is represented excitation direction.

Embodiment

As shown in Figure 1, multiple tooth fault-tolerant permanent magnet flux switching motor comprises salient pole stator, armature winding, field spider 2, it is characterized in that:

Stator salient poles is an E type stator iron block 1, and the space between per two E type stator iron blocks embeds strip permanent magnet 3 successively, twines i.e. first coil to the, six coils of stator winding on two E type arms that above-mentioned strip permanent magnet links to each other.

E type stator iron block be " Y " type structure every the magnetic tooth, make that the stator number of teeth is 4 times of strip permanent magnet number." Y " type structure makes the magnetic conductance every the tooth loop increase greatly every the magnetic tooth, has reduced the mutual inductance of stator winding adjacent windings.

Rotor adopts multiple tooth structure, and its number of teeth can be 17 or 18 or 19.The multiple tooth structure of stator and rotor makes the armature winding self-induction of motor increase, and reduces the location torque of motor simultaneously.The increase of self-induction makes power density, torque density, the efficient of motor improve, and embodiment is as follows:

When coil 1---arbitrary coil fault that is short-circuited in the coil 6, short circuit current i _fExpression formula is shown in (1):

$i_f=\frac{\mathrm{\&phi;}}{\mathrm{NL}}---\left(1\right)$

In the formula (1), φ represents the unloaded permanent magnet flux of coil, and N represents every circle coil turn, and L represents the inductance of single-turn circular coil.Rated current i _LExpression formula is shown in (2):

$i_L=\frac{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="H2009101849471E00011.png"\; state="\{\{state\}\}">T</figure-callout>}}{\frac{3}{2}*{\mathrm{\&phi;}}_{\max }*N}---\left(2\right)$

In the formula (2), T represents the nominal torque of motor, φ _MaxRepresent the unloaded permanent magnet flux amplitude of every phase winding, N represents each coil turn.

Rated current and nominal torque one timing when motor reduce strip permanent magnet quantity and reduce permanent magnet coercive force, then the unloaded permanent magnet flux amplitude φ of the unloaded permanent magnet flux φ of coil and every phase winding _MaxAll reduce, each coil turn of motor increases short circuit current i _fReduce.

Because the inductance of multiple tooth fault-tolerant permanent magnet flux switching motor is bigger, therefore to make winding inductance and rated current product more than or equal to the unloaded permanent magnetism magnetic linkage of winding, the motor windings number of turn that needs to increase will be less than far away every tooth excitation type permanent magnet flux switching motor, thereby the copper loss of multiple tooth fault-tolerant permanent magnet flux switching motor and cost will be lower than every tooth excitation type permanent magnet flux switching motor.

Because the umber of turn that multiple tooth fault-tolerant permanent magnet flux switching motor increases is less, guarantees that so the motor rated voltage is certain, the motor permanent magnet coercive force degree of reduction is less, thereby wants high every power density, the torque density of tooth excitation type permanent magnet flux switching motor.

Claims (1)

1. the fault-tolerance approach of a multiple tooth fault-tolerant permanent magnet flux switching motor, described multiple tooth fault-tolerant permanent magnet flux switching motor comprises salient pole stator, armature winding, field spider (2), stator salient poles is an E type stator iron block (1), space between per two E type stator iron blocks embeds strip permanent magnet (3) successively, twines i.e. first coil to the, six coils of stator winding on two E type arms that above-mentioned strip permanent magnet links to each other;

It is characterized in that: adopt described multiple tooth fault-tolerant permanent magnet flux switching motor, reduce the mutual inductance between the adjacent windings and the location torque of described multiple tooth fault-tolerant permanent magnet flux switching motor, increased described armature winding self-induction, when described multiple tooth fault-tolerant permanent magnet flux switching motor when using the high-coercive force permanent magnet, need not to roll up the armature winding number of turn can be with short circuit current i _fBe suppressed at rated current i _LIn:

$i_f=\frac{\mathrm{\&phi;}}{\mathrm{NL}}<i_L=\frac{T}{\frac{3}{2}*{\mathrm{\&phi;}}_{\max }*N}---\left(1\right)$

Promptly make armature winding inductance and rated current i _LProduct more than or equal to the unloaded permanent magnetism magnetic linkage of armature winding, thereby improve the power density and the efficient of described multiple tooth fault-tolerant permanent magnet flux switching motor,

In the formula (1), φ represents the unloaded permanent magnet flux of coil, and N represents every circle coil turn, and L represents the inductance of single-turn circular coil, and T represents the nominal torque of motor, φ _MaxThe unloaded permanent magnet flux amplitude of representing every phase winding.

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