CN103151859A - Magnetic flow switched and surface-mounted type permanent magnet memory motor - Google Patents

Abstract

The invention discloses a magnetic flux switching type surface-mounted permanent magnet memory motor, which includes a casing, a stator, a rotor and a rotating shaft accommodated in the casing, the rotor is a cylinder with a through hole, and the rotor includes a center The through-hole sleeve and the segmented rotor core, the rotating shaft is fixedly connected in the central through hole of the sleeve; the segmented rotor core is in the shape of a fan, and is evenly distributed along the circumference of the rotor and fixedly connected to the outer surface of the sleeve; the stator includes Stator core, permanent magnet, three-phase armature winding and pulse winding; stator core includes stator yoke and stator teeth; stator teeth are composed of permanent magnet teeth and armature teeth; permanent magnets are tile-shaped, and permanent magnets are fixedly connected to permanent magnets On the outer surface of the teeth; the permanent magnets are radially magnetized, and the magnetization directions of two adjacent permanent magnets are opposite; the three-phase armature winding turns are wound on the armature teeth, and the pulse winding turns are wound on the permanent magnets. The permanent magnet memory motor can improve the motor's magnetic field weakening capability and speed operating range, and the no-load air gap magnetic field is adjustable.

Description

A flux-switching surface-mount permanent magnet memory motor

technical field

The invention relates to an adjustable magnetic flux permanent magnet motor, in particular to a magnetic flux switching surface-mounted permanent magnet memory motor. the

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 speed regulation range 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

The traditional memory motor was proposed in 2001 by Professor Ostovic, a Croatian-German motor 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. the

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. the

In recent years, a new type of stator permanent magnet motor—Switched Flux Permanent Magnet (hereinafter referred to as SFPM) motor has attracted extensive attention from scholars at home and abroad due to its excellent performance. SFPM motors have the advantages of high power density, high efficiency, no-load flux linkage bipolarity, and high sine degree of no-load induced electromotive force. Compared with rotor permanent magnet motors, SFPM motors also have simple installation, good heat dissipation, and low rotation Small inertia, suitable for high-speed operation and other advantages. 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. the

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. the

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. the

Contents of the invention

Technical problem: The technical problem to be solved by the present invention is to provide a flux-switching surface-mounted permanent magnet memory motor, which can improve the motor’s field weakening capability and speed operating range, and the no-load air gap magnetic field can Tune. the

Technical scheme: in order to solve the above technical problems, the technical scheme adopted in the present invention is:

其中，m是永磁记忆电机的相数，n为整数，N_s=6k，k为正整数。  A magnetic flux switching type surface-mounted permanent magnet memory motor, the permanent magnet memory motor includes a casing, and a stator, a rotor and a rotating shaft accommodated in the casing, the casing is fixedly connected to the stator, and the stator is located outside the rotor, The rotor is a cylinder with a through hole. The rotor includes a sleeve with a central through hole and a segmented rotor core. The rotating shaft is fixedly connected in the central through hole of the sleeve. Evenly distributed and fixedly connected on the outer surface of the sleeve; the stator includes a stator core, permanent magnets, three-phase armature windings and pulse windings; the stator core includes a stator yoke and stator teeth protruding from the stator yoke to the center of the stator core ; The stator teeth are composed of permanent magnet teeth and armature teeth with the same number, and the permanent magnet teeth and armature teeth are arranged alternately along the circumference of the stator core; stator slots are formed between adjacent permanent magnet teeth and armature teeth; permanent magnets In the shape of tiles, the permanent magnets are fixedly connected to the outer surface of the permanent magnet teeth, and the permanent magnets are opposite to the rotor; the permanent magnets are radially magnetized, and the magnetization directions of two adjacent permanent magnets are opposite; the three-phase armature The windings and pulse windings are respectively located in the stator slots, and the three-phase armature winding turns are wound on the armature teeth, and the pulse winding turns are wound on the permanent magnets; the number N _r of the segmented rotor core and the number N _s of the stator teeth satisfy:

Wherein, m is the phase number of the permanent magnet memory motor, n is an integer, N _s =6k, and k is a positive integer.

Further, the stator core is U-shaped, and the stator core is made of silicon steel sheets. the

Further, the pulse current direction of the pulse winding is determined according to the magnetization or demagnetization effect of the pulse current magnetomotive force on the permanent magnet wound by the pulse winding. the

Beneficial effect: compared with prior art, the present invention has following beneficial effect:

1. The overall structure of the whole motor is simple. Because the motor adopts the stator permanent magnet structure, the permanent magnet, pulse winding and armature winding are all placed in the stator, which is easy to dissipate heat and cool down. The rotor only acts as a magnetic core. Compared with the traditional permanent magnet synchronous motor, the cylindrical structure of the rotor is very stable in the present invention, which significantly reduces the wind resistance and oil resistance of the motor, and is especially suitable for high-speed operation. the

2. Both the armature winding and the pulse winding adopted by the motor of the present invention adopt concentrated windings, and the armature windings are wound at intervals, which ensures that the flux linkage of the winding turn chain is bipolar, and reduces the mutual influence between the windings. Effectively reduces the length of the end and reduces the end effect of the motor. The copper consumption of the motor is very small, which improves the operating efficiency of the motor. the

3. The utilization rate of the permanent magnet and the magnetic density of the air gap are improved. Different from the traditional magnetic flux switching permanent magnet motor, the present invention adopts a surface-mounted permanent magnet structure, and the permanent magnet is attached to the outer surface of the permanent magnet teeth. This greatly reduces the extra magnetic flux leakage of the motor, improves the utilization rate of the permanent magnet, and relatively reduces the amount of permanent magnet material; and the "magnetic effect" feature of the motor can make the motor use a low coercivity Higher air gap magnetic density is obtained when permanent magnets are used. the

4. Small excitation loss. The motor of the present invention can repeatedly irreversibly charge and demagnetize the permanent magnet on-line at any time, and call it at any time according to the recorded charging and demagnetization parameters to meet the operation target, realize the online magnetic regulation of the air gap magnetic field, and at the same time, the pulse winding only operates in a very short time Internal charge and demagnetization currents are applied. Therefore, compared with the hybrid excitation flux switching motor, the flux switching permanent magnet memory motor has a small excitation loss, and the complexity of the speed control system is relatively small, and there is no interaction between the electric excitation magnetomotive force and the permanent magnet magnetomotive force. The influence and the electromagnetic characteristics of the motor are more complicated. the

5. The motor of the present invention not only has the characteristics of SFPM motor permanent magnet flux linkage and high sine degree of back electromotive force, low harmonic content, and torque and power density compared with other stator permanent magnet motors, but also inherits the prominent weak points of memory motors. Magnetic expansion capability. the

6. The motor of the present invention adopts the magnetic circuit structure of electric excitation magnetic flux and permanent magnetic flux in series, which greatly improves the instantaneous charging and demagnetization efficiency of the permanent magnet by the pulse current, and ensures that the pulse current can be used with fewer turns of the pulse winding. The pulse current can change the magnetization of AlNiCo permanent magnets in a large range, so it is very suitable for aerospace, electric vehicles and other fields. the

Description of drawings

Fig. 1 is a schematic structural diagram of the motor of the present invention, wherein the direction of the arrow indicates the magnetization direction of the permanent magnet. the

Fig. 2 is when the pulsed magnetomotive force magnetizes the permanent magnet, and when the rotor moves to position A, the motor flux path diagram of the present invention, wherein, the dotted rectangular frame represents the permanent magnet flux magnetic field line, and the solid line rectangular frame represents the pulse Current magnetic flux magnetic field lines. the

Fig. 3 is when the pulsed magnetomotive force magnetizes the permanent magnet, and when the rotor moves to position B, the magnetic flux path diagram of the motor of the present invention, wherein, the dotted line rectangular frame represents the permanent magnet flux magnetic field line, and the solid line rectangular frame represents the pulse Current magnetic flux magnetic field lines. the

Fig. 4 is when the pulse magnetomotive force demagnetizes the permanent magnet, and when the rotor moves to position A, the motor flux path diagram of the present invention, wherein, the dotted rectangular frame represents the permanent magnet flux magnetic field line, and the solid line rectangular frame represents the pulse Current magnetic flux magnetic field lines. the

Fig. 5 is when the pulsed magnetomotive force demagnetizes the permanent magnet and the rotor moves to position B, the motor flux path diagram of the present invention, wherein the dotted rectangular frame represents the permanent magnet flux magnetic force line, and the solid rectangular frame represents the pulse Current magnetic flux magnetic field lines. the

In the figure, there are: stator 1, rotor 2, rotating shaft 3, sleeve 201, segmented rotor core 202, stator core 101, permanent magnet 102, three-phase armature winding 103, pulse winding 104, stator yoke 1011, stator teeth 1012, Permanent magnet teeth 1013, armature teeth 1014, and stator slots 1015. the

Detailed ways

The technical solution of the present invention will be described in further detail below in conjunction with the accompanying drawings. the

其中，m是永磁记忆电机的相数，n为整数，N_s=6k，k为正整数。  As shown in FIG. 1 , a flux-switching surface-mounted permanent magnet memory motor of the present invention includes a casing, and a stator 1 , a rotor 2 and a rotating shaft 3 accommodated in the casing. The casing is fixedly connected to the stator 1 , and the stator 1 is located outside the rotor 2 . The rotor 2 is a cylinder with through holes. The rotor 2 includes a sleeve 201 with a central through hole and a segmented rotor core 202 . The rotating shaft 3 is fixedly connected in the central through hole of the sleeve 201; the segmented rotor core 202 is fan-shaped, and is evenly distributed along the circumference of the rotor 2 and fixedly connected to the outer surface of the sleeve 201. Both the shaft 3 and the sleeve 201 are made of non-magnetic materials. Non-magnetic materials can choose aluminum, copper, or steel. The stator 1 includes a stator core 101 , a permanent magnet 102 , a three-phase armature winding 103 and a pulse winding 104 . The permanent magnet 102 is preferably made of Alnico permanent magnet material. The stator core 101 includes a stator yoke 1011 and stator teeth 1012 protruding from the stator yoke 1011 toward the center of the stator core. The stator teeth 1012 are composed of the same number of permanent magnet teeth 1013 and armature teeth 1014 . That is to say, the number of permanent magnet teeth 1013 is equal to the number of armature teeth 1014 . The permanent magnet teeth 1013 and the armature teeth 1014 are arranged alternately along the circumferential direction of the stator core 101 . Stator slots 1015 are formed between adjacent permanent magnet teeth 1013 and armature teeth 1014 . The permanent magnet 102 is tile-shaped, and the permanent magnet 102 is fixedly connected to the outer surface of the permanent magnet tooth 1013 , and the permanent magnet 102 is opposite to the rotor 2 . The permanent magnets 102 are radially magnetized, and the magnetization directions of two adjacent permanent magnets 102 are opposite. The three-phase armature winding 103 and the pulse winding 104 are respectively located in the stator slot 1015 , and the three-phase armature winding 103 turns are wound on the armature tooth 1014 , and the pulse winding 104 turns is wound on the permanent magnet 102 . The number N _r of the segmented rotor core 202 and the number N _s of the stator teeth 1012 satisfy:

Wherein, m is the phase number of the permanent magnet memory motor, n is an integer, N _s =6k, and k is a positive integer.

Further, the stator core 101 is U-shaped, and the stator core 101 is made of silicon steel sheets. The stator core 101 is U-shaped, has a simple and reliable structure, and is easy to process and cool. the

Further, the pulse current direction of the pulse winding 104 is determined according to the magnetization or demagnetization effect of the pulse current magnetomotive force on the permanent magnet 102 wound by the pulse winding 104 . When the pulse current magnetomotive force produces magnetization effect on the permanent magnet 102 wound by the pulse winding 104 turns, the pulse current direction of the pulse winding 104 is the same as the magnetization direction of the permanent magnet 102, and when the pulse current magnetomotive force acts on the pulse winding 104 When the permanent magnet 102 wound with turns produces a demagnetization effect, the pulse current direction of the pulse winding 104 is opposite to the magnetization direction of the permanent magnet 102 . the

The pulse winding 104 in the above structure is a concentrated winding, which is wound on the permanent magnet teeth 1013 of the stator core 101 . The pulse windings 104 are connected in series end to end with alternate teeth to form two groups of single-phase pulse windings. The direction of the pulse currents of the adjacent pulse windings 104 is the same, forming two pairs of alternating distribution on the whole. According to the right-hand rule, the current direction in each pulse winding 104 is the same as or opposite to the magnetization direction on the permanent magnet teeth 1013 . The motor adjusts the residual magnetization intensity of the permanent magnet 102 by applying instantaneous magnetization and demagnetization pulse currents, so as to realize the adjustment of the no-load air gap magnetic field of the motor in a true sense, and improve the magnetic field weakening capability and speed operating range of the motor. the

The AlNiCo permanent magnet material used to make the permanent magnet 102 has the characteristics of high coercive force and high remanence, adopts casting manufacturing process, and has high temperature stability. The magnetic potential of the permanent magnet and the magnetic potential of the pulse winding 104 form a series magnetic circuit. This series magnetic circuit can ensure that the magnetic field of the pulse current is applied to charge and demagnetize it to a large extent, thereby greatly improving the efficiency of electric excitation, improving the operating range of the motor speed and the field weakening capability. the

Since the pulse winding 104 applies an instantaneous current pulse to generate an instantaneous magnetic field, the pulse magnetic potential will not significantly affect the air gap magnetic field, and the air gap magnetic field is mainly provided by the permanent magnet 102 . In practical applications, the magnitude of the magnetomotive force of the charging and demagnetizing pulse current 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

The present invention adopts the cylindrical rotor 2, which has a very stable structure and obviously reduces the wind resistance and oil resistance of the motor. The fan-shaped structure of the segmented rotor core 202 can effectively shorten the magnetic flux path, reduce the mutual inductance between armature windings of different phases, enhance the fault-tolerant operation capability of the motor, and is especially suitable for high-speed operation. the

The working principle of the permanent magnet memory motor with the above structure is as follows:

During the operation of the motor, the magnetic flux (flux linkage) flowing in the armature teeth 1014 of the motor will switch direction according to the different positions of the rotor 2, as shown in Figure 2, because when the motor rotor 2 moves to position A and the rotor 2 When running to position B, the direction of the permanent magnet flux of the 103-turn link of the three-phase armature winding is opposite, so the 103-turn link permanent magnet flux of the three-phase armature winding will induce a sinusoidal waveform and bipolar counter electromotive force, and the rotor 2. During continuous rotation, the magnetic flux direction of the turn chain in the three-phase armature winding 103 changes periodically to realize electromechanical energy conversion. Based on the salient pole effect formed by the stator teeth 1012 and the segmented rotor core 202, and the unequal interlacing characteristics of the stator teeth 1012 and the segmented rotor core 202, the permanent magnet memory motor of the present invention is essentially a new type of reluctance induction permanent Magneto. the

The most important thing is that the pulse winding 104 of the permanent magnet memory motor of the present invention is in an open circuit state during normal operation, and the air gap magnetic field is provided by the alnico permanent magnet 102 alone, which avoids the excitation loss, and generates a magnetic field by applying a pulse current to the aluminum The nickel cobalt permanent magnet 102 is magnetized and demagnetized so that the air gap magnetic field is provided by the permanent magnet 102 with a new flux density level. 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. the

Specifically, as shown in Figure 2, when the rotor 2 moves to position A (at position A: each segmented rotor core 202 on the rotor 2 is respectively connected to a permanent magnet tooth 1013, an armature tooth 1014 and a The stator slots 1015 are opposite, and from left to right, the permanent magnet teeth 1013, the stator slots 1015 and the armature teeth 1014 are arranged in sequence), the pulse magnetomotive force generated by the pulse winding 104 is the same as the magnetization direction of the permanent magnet 102, Indicates that the pulse winding 104 is magnetizing the permanent magnet 102, and when the rotor 2 rotates to position B (at position B: each segmented rotor core 202 on the rotor 2 is respectively connected to a permanent magnet tooth 1013, an armature The tooth 1014 is opposite to a stator slot 1015, and from left to right, the armature tooth 1014, the stator slot 1015 and the permanent magnet tooth 1013 are arranged in sequence), as shown in Figure 3, the permanent magnet through which the armature tooth 1014 flows The magnetic flux will alternate, so that the three-phase armature winding 103 induces a sinusoidal alternating back electromotive force. Similarly, when the motor is running in the demagnetized state of the permanent magnet 102, when the rotor 2 rotates to position A, the motor flux path is shown in Figure 4; when the rotor 2 rotates to position B, the motor flux path is shown in Figure 5 Show. FIG. 4 is relative to FIG. 2 , and FIG. 5 is relative to FIG. 3 , only the current direction of the pulse winding 104 is reversed. That is to say, in FIG. 4 and FIG. 5 , the permanent magnet 102 works in a demagnetized state, while in FIG. 2 and FIG. 3 , the permanent magnet 102 works in a magnetized state. the

The above is only a preferred embodiment of the present invention. It should be pointed out that the rotor of the motor can be in the form of a chute, which is beneficial to improve the sinusoidal nature of the back electromotive force and realize the sensorless operation of the motor. The invention is also applicable to the external rotor magnetic flux switching type surface-mounted permanent magnet memory motor. the

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. the

Claims (6)

1. Magneticflux-switching type surface-mount type permanent magnetism memory electrical machine, it is characterized in that: this permanent magnetism memory electrical machine comprises casing, and be housed in stator (1), rotor (2) and rotating shaft (3) in casing, casing is fixedly connected on stator (1), stator (1) is positioned at the outside of rotor (2), rotor (2) is the cylinder with through hole, rotor (2) comprises sleeve (201) and the piecemeal rotor core (202) that is provided with central through hole, and rotating shaft (3) is fixedly connected in the central through hole of sleeve (201); Piecemeal rotor core (202) is fan shape, and circumferentially evenly distributes and be fixedly connected on the outer surface of sleeve (201) along rotor (2);

Stator (1) comprises stator core (101), permanent magnet (102), threephase armature winding (103) and pulse winding (104); Stator core (101) comprises stator yoke (1011) and the stator tooth (1012) that protrudes to the stator core center position from stator yoke (1011); Stator tooth (1012) is comprised of quantity identical permanent magnetism tooth (1013) and armature tooth (1014), and permanent magnetism tooth (1013) and armature tooth (1014) are circumferentially alternately arranged along stator core (101); Form stator slot (1015) between adjacent permanent magnetism tooth (1013) and armature tooth (1014);

Permanent magnet (102) is tile, and permanent magnet (102) is fixedly connected on the outer surface of permanent magnetism tooth (1013), and permanent magnet (102) is relative with rotor (2); Permanent magnet (102) radial magnetizing, and the magnetizing direction of adjacent two permanent magnets (102) is opposite;

Threephase armature winding (103) and pulse winding (104) lay respectively in stator slot (1015), and threephase armature winding (103) circle is on armature tooth (1014), and pulse winding (104) circle is on permanent magnet (102);

The quantity N of piecemeal rotor core (202) _rAnd the quantity N of stator tooth (1012) _sSatisfy: Wherein, m is the number of phases of permanent magnetism memory electrical machine, and n is integer, N _s=6k, k are positive integer.

2. Magneticflux-switching type surface-mount type permanent magnetism memory electrical machine according to claim 1, it is characterized in that: described stator core (101) is U-shaped, and stator core (101) is made by silicon steel sheet.

3. Magneticflux-switching type surface-mount type permanent magnetism memory electrical machine according to claim 2 is characterized in that: the pulse current direction of described pulse winding (104) according to the pulse current magnetomotive force to this pulse winding (104) circle around permanent magnet (102) produce the effect of magnetizing or demagnetizing effect decides.

4. Magneticflux-switching type surface-mount type permanent magnetism memory electrical machine according to claim 1, it is characterized in that: described permanent magnet (102) is made by the Al-Ni-Co permanent magnet material.

5. Magneticflux-switching type surface-mount type permanent magnetism memory electrical machine according to claim 1, it is characterized in that: described rotating shaft (3) and sleeve (201) are made by non-magnet material.

6. Magneticflux-switching type surface-mount type permanent magnetism memory electrical machine according to claim 1, it is characterized in that: described rotating shaft (3) and sleeve (201) are by aluminium, copper, and perhaps steel is made.

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