CN103051138B - Multi-tooth magnetic flux switching permanent magnetic memory motor - Google Patents

Abstract

The invention discloses a multi-tooth magnetic flux switching permanent magnet memory motor, which comprises a casing, a stator accommodated in the casing, a rotor (2) and a non-magnetic rotating shaft (8), and the stator (1) is arranged on the rotor ( 2) External; the rotor (2) is fixed on the non-magnetic rotating shaft (8), which is a salient pole type; the stator includes a stator core (1), a permanent magnet (3), a three-phase armature winding (4) and a pulse winding ( 5); the stator core (1) includes several stator yokes and stator poles protruding from the stator yoke to the center of the stator core; the three-phase armature concentrated winding (4) is wound on the stator poles; the permanent magnet (3) is embedded in the stator In the pole, there is a cavity (6) between the permanent magnet (3) and the non-magnetic rotating shaft (8), and the pulse winding (5) is arranged in the cavity (6); the pulse winding (5) and the casing There is a magnetic bridge (7) between them. The invention improves the magnetic field weakening capability and the operating range of the rotating speed of the motor, and increases the magnetic density of the air gap of the motor.

Description

A multi-tooth flux switching permanent magnet memory motor

technical field

The invention relates to an adjustable magnetic flux permanent magnet motor, in particular to a novel magnetic flux switching permanent magnet memory motor, which can improve the magnetic field weakening capability of the motor, is suitable for wide speed regulation operation occasions, and belongs to the technical field of motor manufacturing.

Background technique

In the field of motors, due to the inherent characteristics of ordinary permanent magnet materials (such as NdFeB), the air gap magnetic field in the motor is basically kept constant, and the range of speed regulation is very limited when operating as an electric motor. The application of wide-speed adjustable direct drive applications such as electric vehicles and aerospace is limited to a certain extent. Therefore, the adjustable flux permanent magnet motor aimed at realizing the effective adjustment of the air gap magnetic field of the permanent magnet motor has always been a hot spot and difficulty in the field of motor research. . Permanent magnet memory motor (hereinafter referred to as "memory motor") is a new type of flux controllable permanent magnet motor, which uses low coercivity alnico permanent magnets to generate a circumferential magnetic field through stator windings or DC pulse windings. Thereby changing the magnetization intensity of the permanent magnet to adjust the air gap magnetic field, and at the same time the magnetic density level of the permanent magnet has the characteristic of being memorized by the permanent magnet.

The traditional memory motor was proposed in 2001 by Professor Ostovic, a Croatian-German electrical scholar. The memory motor of this topology is developed from the pole-writing motor, and the rotor consists of an AlNiCo permanent magnet, a non-magnetic interlayer and a rotor core to form a sandwich structure. This special structure can repeatedly irreversibly charge and demagnetize the permanent magnet online at any time, and at the same time reduce the influence of the quadrature-axis armature reaction on the air-gap magnetic field.

However, there are deficiencies in the rotor structure of the memory motor with this basic structure. Due to the use of AlNiCo permanent magnets, in order to obtain sufficient magnetic flux, materials with sufficient thickness must be used. However, under the above-mentioned tangential structure, it is not easy to realize; at the same time, the rotor must be treated with magnetic isolation, and the whole rotor is fastened on the shaft by multiple parts, which reduces the mechanical reliability; finally, in the occasion where wide speed regulation is required , such as in machine tools and electric vehicles, the main magnetic flux of the permanent magnet air gap adopting the above structure is not high, and the power index of the motor is not satisfactory.

In recent years, a new type of stator permanent magnet motor-Switched Flux Permanent Magnet (SFPM) motor has attracted extensive attention from scholars at home and abroad due to its excellent performance. SFPM motor has the advantages of high power density, high efficiency, no-load flux bipolarity, high sine degree of no-load induced electromotive force, simple structure and high reliability. In the field of permanent magnet synchronous motors, SFPM motors have gradually replaced traditional built-in and surface-mounted permanent magnet motors, and have greater industrial value in aviation and other fields.

However, there are hysteresis loss and eddy current loss in the rotor core of traditional SFPM motors, and the air gap magnetic field is generated by permanent magnet excitation, which is difficult to adjust, which limits its application in electric vehicles with wide speed regulation; secondly, there is also the problem of magnetic flux leakage. The utilization rate of permanent magnets is not high, resulting in electromagnetic compatibility problems.

French scholar Emmanuel. Huang (E.Hoang) proposed a hybrid excitation flux switching permanent magnet (Hybrid Excitation Switched Flux Permanent Magnet, hereinafter referred to as HESFPM) motor. Its characteristics are: the adjustable air gap magnetic field is realized, the permanent magnet utilization rate and power density are improved, and the cogging torque is small; protrude. However, this kind of motor has two magnetic potential sources at the same time, and the two magnetic fluxes are easy to couple and influence each other, which increases the complexity of electromagnetic characteristics, and has weaknesses such as increased excitation loss and difficult implementation of the excitation current control system.

Contents of the invention

Technical problem: The technical problem to be solved by the invention is to propose a multi-tooth switched flux permanent magnet memory motor (Multi-tooth Switched Flux Memory Machine) with high power density and outstanding air gap flux adjustability.

Technical solution: In order to solve the above technical problems, the present invention discloses a multi-tooth magnetic flux switching permanent magnet memory motor, which includes a casing, a stator contained in the casing, a rotor and a non-magnetic rotating shaft, and the stator is arranged outside the rotor ;The rotor is fixed on the non-magnetic rotating shaft, which is a salient pole type;

The stator includes stator core, permanent magnet, three-phase armature winding and pulse winding; the stator core includes several stator yokes and stator poles protruding from the stator yoke to the center of the stator core;

The three-phase armature concentrated winding is wound on the stator pole;

The permanent magnet is embedded in the stator pole, and a cavity is provided between the permanent magnet and the non-magnetic rotating shaft, and the pulse winding is arranged in the cavity; a magnetic bridge is provided between the pulse winding and the casing.

Preferably, the shape of the stator core is "V", and the material is silicon steel sheet.

Preferably, the stator pole includes a main body of the stator pole and a plurality of armature teeth extending inward from the main body of the stator pole;

Wherein, the second armature teeth are composed of permanent magnets and the permeable core edge of the stator pole body of the "V"-shaped stator silicon steel sheet, and independent first armature teeth are respectively provided on both sides of the second armature teeth.

Preferably, the pulse windings are all concentrated windings, the pulse windings are wound on the stator yoke of the stator core, the pulse windings are connected in series end to end to form a single-phase pulse winding, and the pulse current directions are alternately distributed.

Preferably, the permanent magnet is an alnico permanent magnet material with a trapezoidal structure, the permanent magnet is magnetized tangentially along the circumference, N poles and S poles are alternately arranged, and the shape is a trapezoidal structure.

Preferably, the cavity has an inverted trapezoidal structure, and the two bottom corners are smooth and rounded.

Beneficial effects: 1. The overall structure of the whole motor is simple. Since the motor adopts a stator permanent magnet structure, the alnico permanent magnet, pulse winding, and armature winding are all placed in the stator, which is easy to dissipate heat and cool, and improve power density. The rotor structure is very stable, especially suitable for high-speed operation.

2. The armature winding pulse winding used in this motor adopts centralized winding, which effectively reduces the length of the end and reduces the effect of the end of the motor. And the copper consumption is very small, which improves the operating efficiency of the motor.

3. The stator core of this motor adopts a multi-tooth structure. On the premise of keeping the inner and outer diameters of the stators, the length of the air gap, the width of the rotor teeth, the thickness of the permanent magnets, the material of the permanent magnets and the number of turns, etc., the multi-tooth magnetic flux switching type The motor can save a lot of permanent magnets and simplify the processing. At the same time, under light load conditions, the multi-tooth flux switching motor has the characteristics of high torque density and small torque ripple.

4. This motor can repeatedly irreversibly charge and demagnetize the alnico permanent magnet online at any time, and call it at any time according to the recorded charging and demagnetization parameters to meet the operation target, and realize the online magnetic regulation of the air gap magnetic field. At the same time, the pulse winding is only in the very Apply charge and demagnetization current in a short time.

5. This motor inherits the outstanding magnetic field weakening speed expansion capability of the memory motor, and the magnetic bridge structure is provided to ensure that the pulse current can change the magnetization intensity of the AlNiCo permanent magnet in a large range by using fewer pulse winding turns. , so it is very suitable for aerospace, electric vehicles and other fields.

Description of drawings

Fig. 1 is a schematic diagram of the motor structure of the present invention, wherein the direction of the arrow represents the magnetization direction of the permanent magnet;

Fig. 2 is the outer rotor form of the present invention, that is, the outer rotor multi-tooth magnetic flux switching type permanent magnet memory motor, wherein the direction of the arrow indicates the magnetization direction of the permanent magnet;

In the figure: 1 stator core, 2 rotor, 3 alnico permanent magnet, 4 three-phase armature winding, 5 single-phase pulse winding, 6 pulse winding cavity, 7 magnetic bridge, 8 non-magnetic rotating shaft, 1.1 first Armature teeth, 1.2 second armature teeth.

Detailed ways

Below in conjunction with accompanying drawing, the present invention will be further described.

The invention discloses a multi-tooth magnetic flux switching type permanent magnet memory motor, which comprises a casing, a stator accommodated in the casing, a rotor 2 and a non-magnetic rotating shaft 8, the stator 1 is arranged outside the rotor 2; the rotor 2 is fixed on the On the non-magnetic rotating shaft 8, it is a salient pole type; the stator includes a stator core 1, a permanent magnet 3, a three-phase armature winding 4 and a pulse winding 5; the stator core 1 includes a number of stator yokes and the direction from the stator yoke to the center of the stator core Protruding stator poles; three-phase armature concentrated windings 4 are wound on the stator poles; permanent magnets 3 are embedded in the stator poles, a cavity 6 is provided between the permanent magnets 3 and the non-magnetic rotating shaft 8, and the pulse winding 5 is arranged on Inside the cavity 6, a magnetic bridge 7 is provided between the pulse winding 5 and the casing.

The shape of the stator core 1 is "V", and the material is silicon steel sheet.

The stator pole includes a main body of the stator pole and a plurality of armature teeth extending inward from the main body of the stator pole;

Among them, the second armature tooth 1.2 is composed of the permanent magnet 3 and the magnetic core edge of the stator pole main part of the "V"-shaped stator silicon steel sheet 1, and the two sides of the second armature tooth 1.2 are respectively provided with independent first armatures. Teeth 1.1.

The pulse windings 5 are all concentrated windings, and the pulse windings 5 are wound on the stator yoke of the stator core 1, and the pulse windings 5 are connected in series end to end to form a single-phase pulse winding, and the direction of the pulse current is alternately distributed.

The permanent magnet 3 is an alnico permanent magnet material with a trapezoidal structure. The permanent magnet 3 is magnetized tangentially along the circumference, N poles and S poles are alternately arranged, and the shape is a trapezoidal structure.

The cavity 6 is an inverted trapezoidal structure, and the two bottom corners are smooth and rounded.

Each of the stator teeth is composed of "trapezoidal" AlNiCo permanent magnets and "V"-shaped stator cores. The permanent magnets are magnetized along the circumferential direction, and the N poles and S poles are alternately distributed; the single-phase pulse windings are concentrated windings. On the stator yoke, the adjacent pulse windings are connected in series end to end, and the direction of the pulse current is distributed alternately. The three-phase windings of the stator are concentrated windings.

The stator core adopts a multi-tooth magnetic accumulation structure, which saves the amount of permanent magnet materials and effectively improves the air gap flux density of the motor; at the same time, the tooth flux switching permanent magnet memory motor has a high torque density under light load conditions. And the characteristics of small torque ripple.

The permanent magnet adopts a special AlNiCo permanent magnet. The permanent magnet material has the characteristics of high coercive force and high remanence. It adopts a casting manufacturing process and has high temperature stability. The magnetic potential of the permanent magnet and the magnetic potential of the pulse winding form a parallel magnetic circuit. The trapezoidal design can ensure that the magnetic field of the applied pulse current can charge and demagnetize it to a large extent, so as to realize the adjustable air gap magnetic field of the motor, improve the operating range of the motor speed and the field weakening ability.

The cavity of the pulse winding adopts an "inverted trapezoidal" shape, and a smooth transition is adopted between the two bottom corners and the bottom edge; the pulse excitation magnetic force line is closed by the iron core, the permanent magnet and the magnetic bridge, so that less pulse winding is used The number of turns can ensure that the pulse current has a better magnetic modulation effect on the AlNiCo permanent magnet.

The magnetic bridge can provide a closed loop for the magnetic circuit of the pulse winding, reduce the copper loss of electric excitation, and realize the flexible and adjustable characteristic of the magnetic field strength of the permanent magnet. Moreover, the magnetic permeable bridge and the "V"-shaped stator core are integrated.

The operating principle of a multi-tooth flux switching permanent magnet memory motor of the present invention is as follows:

The magnetic flux (flux linkage) of the turn chain in the stator winding of the motor will switch direction according to the different positions of the rotor, so a sinusoidal waveform and bipolar back electromotive force will be induced. When the rotor rotates continuously, the magnetic flux direction of the turn chain in the stator winding will It changes periodically to realize electromechanical energy conversion. Due to the saliency effect formed by the stator and rotor teeth and the unequal interlacing characteristics of the stator and rotor teeth, the flux switching permanent magnet memory motor is essentially a new type of reluctance induction permanent magnet motor.

The most important thing is that the pulse winding of the multi-tooth flux switching permanent magnet memory motor is in an open state during normal operation, and the air gap magnetic field is provided by the alnico permanent magnet alone, which avoids the excitation loss, and the magnetic field is generated by applying pulse current. AlNiCo permanent magnets are augmented and demagnetized to provide an air-gap magnetic field from permanent magnets with new flux density levels. Due to the "memory" function of the permanent magnet, the flexible controllability of the air gap magnetic field of the motor can be realized by adjusting the direction and magnitude of the pulse current, and the constant power operating range of the motor can be widened when the motor operates as a motor.

As shown in Figure 1, a multi-tooth flux switching permanent magnet memory motor of the present invention mainly includes a stator part and a rotor part. It is characterized in that the stator part includes a multi-tooth stator core 1, an alnico permanent magnet 3, a three-phase armature concentrated winding 4 and a pulse winding 5; the rotor 2 is fixed on a non-magnetic rotating shaft 8, which is a salient pole type; The stator part fixed in the shell 9 is composed of a "V"-shaped silicon steel sheet magnetic core 1 and a trapezoidal permanent magnet 3 in sequence along the circumferential direction; an inverted trapezoidal cavity 6 is left between the stator yoke and the permanent magnet 3 for placing pulses. Winding 5; a magnetic bridge 7 is provided between the pulse winding cavity 6 and the casing. As specifically shown in FIG. 1 , the stator has six armature teeth wound with armature windings and six pulse winding cavities 6 .

The above-mentioned inverted trapezoidal pulse winding cavity 6 and the casing are provided with a magnetic bridge structure 7, and the magnetic bridge and the "V"-shaped stator core are integrated to provide a corresponding parallel magnetic circuit for the pulse magnetic force magnetic force line, so that the The invention adopts fewer turns of the pulse winding to ensure that the pulse current has a better online magnetic modulation effect on the alnico permanent magnet 3 .

The stator pole includes the main body of the stator pole and a number of armature teeth extending inward from the main body of the stator pole; specifically, the permanent magnet 3 magnetized along the circumferential direction and the guide of the main body of the stator pole of the "V"-shaped stator silicon steel sheet 1 The side of the magnet core constitutes the second armature tooth 1.2, and the two sides of the second armature tooth 1.2 are respectively provided with independent first armature teeth 1.1; and the pulse winding 5 is wound on the stator yoke part of the "V"-shaped stator core, and The single-phase pulse windings are formed in series end to end in sequence. As specifically shown in FIG. 1 , the stator has six armature teeth wound with armature windings and six pulse winding cavities 6 .

By loading the three-phase armature winding with a three-phase voltage of frequency f, a three-phase current of frequency f flows through the three-phase armature winding, so the speed of the motor is n=60 f/p (p is the number of pole pairs of the motor) , the speed of the motor can be adjusted by controlling the voltage and frequency applied to the three-phase armature winding. The single-phase pulse winding is directly connected to the DC power supply. According to the needs of the motor operation, the pulse winding is loaded with a transient forward or reverse pulse current to charge and demagnetize the AlNiCo permanent magnet of the motor, thereby affecting the gas flow of the motor. The gap magnetic field realizes the complete controllability of the motor flux.

Since the pulse winding 5 applies an instantaneous current pulse to generate an instantaneous magnetic field, the pulse magnetic potential will not significantly affect the air gap magnetic field, which is mainly provided by the AlNiCo permanent magnet 3 . In practical applications, the radial thickness of the magnetic permeable bridge 7 can be appropriately selected according to the required magnetic adjustment coefficient, so as to achieve the optimal online adjustment of the air gap magnetic field.

The above descriptions are only preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments, but all equivalent modifications or changes made by those of ordinary skill in the art according to the disclosure of the present invention should be included within the scope of protection described in the claims.

Claims (1)

1. A multi-tooth magnetic flux switching type permanent magnet memory motor, comprising a casing, a stator contained in the casing, a rotor (2) and a non-magnetic rotating shaft (8), characterized in that: the stator (1) is located at The outside of the rotor (2); the rotor (2) is fixed on the non-magnetic rotating shaft (8) and is salient pole type; The stator includes a stator core (1), a permanent magnet (3), a three-phase armature winding (4) and a pulse winding (5); the stator core (1) includes a number of stator yokes and a stator pole; The three-phase armature concentrated winding (4) is wound on the stator pole; The permanent magnet (3) is embedded in the stator pole, and a cavity (6) is provided between the stator yoke and the permanent magnet (3), and the pulse winding (5) is arranged in the cavity (6); the pulse winding (5 ) and the casing are provided with a magnetic bridge (7); The shape of the stator core (1) is "V", and the material is silicon steel sheet; The stator pole includes a main body of the stator pole and a plurality of armature teeth extending inward from the main body of the stator pole; Wherein, the second armature teeth (1.2) are composed of permanent magnets (3) and the conductive core side of the stator pole main part of the "V"-shaped stator core (1), and the two sides of the second armature teeth (1.2) are respectively provided with There is an independent first armature tooth (1.1); The pulse windings (5) are all concentrated windings, the pulse windings (5) are wound on the stator yoke of the stator core (1), the pulse windings (5) are connected in series end to end to form a single-phase pulse winding, and the pulse current directions are alternately distributed; The permanent magnet (3) is an alnico permanent magnet material with a trapezoidal structure, the permanent magnet (3) is magnetized tangentially along the circumference, N poles and S poles are arranged alternately, and the shape is a trapezoidal structure; The cavity (6) has an inverted trapezoidal structure, and the two bottom corners are smooth and rounded.