CN104795951B - A Flux Controllable Axial Field Hybrid Permanent Magnet Memory Motor - Google Patents

Abstract

The invention discloses a magnetic flux controllable axial magnetic field mixed hybrid permanent magnet memory motor comprising two rotor discs, a stator and an installation shaft. NdFeB permanent magnets and iron core poles, which are arrayed in inner and outer circles at intervals alternately, are bonded to the inner surfaces of the rotor discs; the NdFeB permanent magnets are magnetized axially, the polarities of the NdFeB permanent magnets of the outer circle are the same, the polarities of the NdFeB permanent magnets of the inner circle are opposite to those of the NdFeB permanent magnets of the outer circle, and the magnetizing directions of the NdFeB permanent magnets arranged in corresponded positions of two rotor discs are the same; the stator comprises a stator iron core, a three-phase armature winding and a single-phase pulse winding. The motor has high power density and wide rotating speed operation range and is adaptive to relevant drive occasions of low axial size requirements, compacted structure and flux weakening requirements.

Description

A Flux Controllable Axial Field Hybrid Permanent Magnet Memory Motor

technical field

The invention relates to the technical field of permanent magnet motors, in particular to an axial magnetic field hybrid permanent magnet memory motor with controllable magnetic flux.

Background technique

With the continuous improvement of the performance of rare earth permanent magnet materials, permanent magnet motors characterized by high efficiency and high power density have developed rapidly, and have been widely used in many industrial fields such as aviation, aerospace, and automobiles. Among all kinds of permanent magnet motors, axial field permanent magnet motors, also known as disc motors, not only have the characteristics of short axial size, small size, and compact structure, but also because of their high torque density and high efficiency, It has obvious advantages in many special applications and has become a research hotspot. It is mainly used in motion control, especially suitable for direct drive applications with small axial size requirements and large torque requirements, such as electric vehicle hub motors.

As a permanent magnet synchronous motor for driving, it is hoped that when the motor works in the low-speed constant torque region, the air-gap magnetic field is high enough to have a high force index; and when the motor works in the high-speed constant power region, the air-gap magnetic field should be able to The attenuation is low enough to allow the motor to have a wide speed range. Due to the inherent characteristics of permanent magnet materials such as NdFeB, the conventional axial magnetic field permanent magnet synchronous motor keeps the air gap magnetic field in the motor basically constant, which limits its application in wide speed regulation direct drive applications such as electric vehicles. At present, in order to maintain the constant power operation of the permanent magnet motor in a wide speed range, people have adopted the field-weakening speed expansion technology to expand the output power of the permanent magnet motor at high speed. In the prior art, there are mainly two schemes for realizing field-weakening control of permanent magnet motors. One is to adjust the armature current through the controller, and use the demagnetization magnetic potential generated by the direct axis current component in the armature winding to offset the generation of some permanent magnets. In order to achieve the purpose of weakening the main magnetic flux; the second is to adopt a hybrid excitation scheme, that is, to add a DC excitation coil on the basis of the traditional permanent magnet motor, and the magnetomotive force generated by the DC coil above the base speed is used as Demagnetization magnetic potential, to achieve the purpose of weakening the magnetic flux. Although the above solution can achieve the purpose of weakening the magnetic flux, it needs to add a controller or a DC excitation coil, which will cause an increase in copper loss, which will lead to a decrease in the efficiency of the system in the high-speed area, and may cause irreversible demagnetization of the permanent magnet.

Therefore, how to realize the adjustable air gap magnetic field of permanent magnet motors has become a research hotspot in the field of motors in recent years. A method of adjusting the air gap magnetic field by changing the magnetization level of permanent magnets is called a real variable flux permanent magnet. Magneto. This type of motor adopts AlNiCo, a permanent magnet material with high remanence and low coercive force, and uses the direct-axis armature magnetomotive force generated by DC pulse winding current or three-phase stator winding current to control its magnetization intensity, and its The magnetization level can be memorized, so that the flexible adjustment of the air-gap permanent magnet magnetic field can be realized, and the wide speed range operation can be realized without sacrificing other performance indicators of the motor. Since the magnetization of the motor is to directly change the magnetization state of the permanent magnet, instead of using an external magnetomotive force to offset it, it can be said to be a permanent magnet motor with flux control in the true sense.

Lin Heyun of Southeast University proposed a surface-mounted permanent magnet memory motor with axial magnetic flux switching. Although the motor can adjust the air gap magnetic field by applying different currents to the single-phase pulse winding, the motor is only AlNiCo permanent magnets with relatively low coercive force are used, and the maximum air gap flux of the motor is difficult to reach the level of NdFeB permanent magnet motors, and the power index of the motor is not satisfactory; or in order to obtain sufficient flux Therefore, thicker permanent magnet materials must be used, and the magnetization and demagnetization fluxes pass through the air gap of the motor, which leads to a larger magnetomotive force of the magnetic modulation pulse and increases the winding capacity.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a flux controllable axial magnetic field hybrid permanent magnet memory motor, and provide a hybrid permanent magnet motor with higher power density and flux controllability Memory motor, this motor not only meets the requirements of field weakening and speed expansion of the hub motor of electric vehicles, but also can obtain high power index at the same time.

The present invention adopts the following technical solutions for solving the problems of the technologies described above:

A magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor proposed according to the present invention includes two rotor disks, a stator and a mounting shaft, the two rotor disks are symmetrically arranged on both sides of the stator, the stator and the two rotor disks Coaxially installed on the installation shaft; it is characterized in that the inner and outer circles of NdFeB permanent magnets and core poles arranged alternately and alternately are pasted on the inner surface of the rotor disc, wherein the NdFeB permanent magnet shaft Magnetically charged, the polarity of the NdFeB permanent magnets on the outer ring is consistent, the polarity of the NdFeB permanent magnets on the inner ring is opposite to that of the NdFeB permanent magnets on the outer ring, and the relative positions of the two rotor disks The magnetization direction of NdFeB permanent magnets is the same.

As a further optimization scheme of a magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor according to the present invention, the stator includes a stator core, a three-phase armature winding and a single-phase pulse winding; the stator core is bilaterally symmetrical, and the stator The iron core includes the stator yoke and the stator teeth, the stator teeth and the stator yoke are assembled into a cylindrical shape, and the stator slots are formed between the adjacent stator teeth; the three-phase armature winding and the single-phase pulse winding are located in the stator slot and wound on the stator teeth superior.

As a further optimization scheme of the magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor described in the present invention, the stator core is made of silicon steel sheets.

As a further optimization scheme of the magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor described in the present invention, AlNiCo permanent magnets are fixed at intervals on the stator teeth, forming alternately arranged stator permanent magnet teeth and stator teeth. The core teeth, the three-phase armature winding turns are wound on the stator core teeth, and the single-phase pulse winding turns are wound on the stator permanent magnet teeth.

As a further optimization scheme of a magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor according to the present invention, the magnetization state of the alnico permanent magnet is determined by the magnitude and direction of the pulse current of the single-phase pulse winding.

As a further optimization scheme of a magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor according to the present invention, the alnico permanent magnet is in the shape of a fan and is axially magnetized.

As a further optimization scheme of the magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor described in the present invention, the three-phase armature winding and the single-phase pulse winding both adopt the non-overlapping concentrated winding type.

As a further optimization scheme of a magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor according to the present invention, the number of the NdFeB permanent magnets and the core poles are the same.

As a further optimization scheme of the magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor of the present invention, the rotor disk is made of non-magnetic material.

As a further optimization scheme of a magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor according to the present invention, the shapes of the NdFeB permanent magnets and the core poles are fan-shaped, and they are located in the same radial direction on the rotor disk. They are NdFeB permanent magnets and core poles.

Compared with the prior art, the present invention adopts the above technical scheme and has the following technical effects:

(1) The motor proposed by the present invention combines the advantages of the disc permanent magnet motor and the memory motor, adds AlNiCo permanent magnets and single-phase pulse windings in the stator structure, and adjusts the AlNiCo permanent magnets by controlling the magnitude and direction of the pulse current. The magnetization state of the magnet, thereby adjusting the air gap magnetic field of the motor; at the same time, the motor structure of the present invention retains the characteristics of compact structure and small magnetic flux leakage of the disc permanent magnet motor, which is convenient to manufacture and is very suitable for thin installation occasions, such as electric motors Wheel drive motors for automobiles, etc.;

(2) The inner surface of the rotor disk of the present invention is divided into inner and outer circles, and high-performance NdFeB permanent magnets and iron core poles are pasted according to the law. The maximum air gap flux and torque density are greatly improved;

(3) The core pole on the surface of the rotor disc of the present invention provides a low reluctance flux path for the pulse current, so that the NdFeB permanent magnet is not affected by the magnetic field;

(4) Both the three-phase armature winding and the single-phase pulse winding of the motor of the present invention adopt the concentrated winding type, which effectively reduces the end length and saves copper wire materials;

(5) Both the permanent magnets on the rotor and the stator of the present invention adopt a surface-mounted structure, and anaerobic adhesive is used to paste the permanent magnets on the surface of the disk, which is convenient to manufacture, greatly reduces the magnetic flux leakage of the motor, and improves the utilization rate of the permanent magnets; At the same time, the surface-mounted installation method is conducive to the heat dissipation of the permanent magnet material of the motor, reduces heat loss, and further improves the operating efficiency of the motor.

Description of drawings

Fig. 1 is a schematic three-dimensional structure diagram of an embodiment of a motor of the present invention: (a) is a first rotor disk, (b) is a stator, and (c) is a second rotor disk.

Fig. 2 is a plane expanded view of the running state of the motor of the present invention.

The reference signs in the figure are interpreted as: 1-rotor disk, 2-NdFeB permanent magnet, 3-core pole, 4-stator core, 5-stator permanent magnet tooth, 6-stator core tooth, 7-three-phase electric Pivot winding, 8-single-phase pulse winding.

detailed description

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:

Figure 1 is a three-dimensional structural schematic diagram of an embodiment of the motor of the present invention: (a) in Figure 1 is the first rotor disk, which is arranged on one side of the stator, (b) in Figure 1 is the stator, and (c) in Figure 1 ) is the second rotor disc, which is set on the other side of the stator. A magnetic flux controllable axial magnetic field hybrid permanent magnet memory motor, including two rotor disks 1, a stator and a mounting shaft, the two rotor disks are symmetrically arranged on both sides of the stator, and the stator and the two rotor disks are coaxially installed on the Installed on the shaft; on the inner surface of the rotor disk, there are respectively pasted NdFeB permanent magnets 2 and core poles 3 arranged alternately in inner and outer circles, that is, on the inner surface of the rotor disk, it is formed by the center of the circle. In the circumferential direction, NdFeB permanent magnets and core poles arranged alternately in the inner and outer circles are pasted in sequence. The polarity of the NdFeB permanent magnets on the ring is opposite to that of the NdFeB permanent magnets on the outer ring, and the opposite positions of the NdFeB permanent magnets on the two rotor disks have the same magnetization direction.

The stator includes a stator core 4, a three-phase armature winding and a single-phase pulse winding; the stator core is bilaterally symmetrical, the stator core includes a stator yoke and stator teeth, the stator teeth and the stator yoke are assembled into a cylindrical shape, and the adjacent stator teeth A stator slot is formed between them; the three-phase armature winding 7 and the single-phase pulse winding 8 are located in the stator slot and wound on the stator teeth.

The stator core is made of silicon steel sheet.

Alnico permanent magnets are fixed at intervals on the stator teeth, forming alternately arranged stator permanent magnet teeth 5 and stator core teeth 6, the three-phase armature winding turns are wound on the stator core teeth, and the single-phase pulse winding turns are wound on the stator teeth. on the permanent magnet teeth of the stator.

The magnetization state of the AlNiCo permanent magnet is determined by the magnitude and direction of the pulse current of the single-phase pulse winding. The magnitude and direction of the pulse current of the single-phase pulse winding determine the magnetization state of the alnico permanent magnet, thereby controlling the strength of the synthesized magnetic field in the air gap of the motor.

The AlNiCo permanent magnet is fan-shaped and magnetized in the axial direction.

Preferably, both the three-phase armature winding and the single-phase pulse winding adopt the non-overlapping concentrated winding type, the winding termination part is shorter, the consumption is less, the copper consumption is less, and the structure of this winding type is simple, and the processing is convenient.

The number of the NdFeB permanent magnets and the core poles is the same.

The rotor disc is made of non-magnetic material.

The shapes of the NdFeB permanent magnets and the core poles are fan-shaped, and the NdFeB permanent magnets and the core poles are respectively located in the same radial direction on the rotor disk.

The stator is arranged between two rotor disks to form an axial double air gap motor, and the stator and the rotor disk are coaxially installed to form a three-disk structure of the inner stator of the outer rotor disk; the structures of the two rotor disks are the same, And it is arranged symmetrically about the stator; the inner surface of the rotor disk is divided into two circles: the inner and outer circles are respectively pasted with 8 sector-shaped NdFeB permanent magnets and 8 sector-shaped iron core poles; the NdFeB permanent magnets are axially filled Magnetic, there is a gap between the permanent magnets and the core poles, arranged at intervals, the polarity of the permanent magnets in the outer ring is the same, and the polarity of the permanent magnets in the inner ring is opposite, and the magnetization direction of the two opposite permanent magnets on the two rotors same.

The stator core includes a stator yoke and stator teeth, and 8 fan-shaped alnico permanent magnets are fixed at intervals on the 16 stator teeth, forming a regular arrangement of 8 stator permanent magnet teeth and 8 stator core teeth alternately, adjacent A stator slot is formed between the stator permanent magnet teeth and the stator core teeth; the three-phase armature winding and the single-phase pulse winding are located in the stator slot, the three-phase armature winding turns are wound on the stator core teeth, and the single-phase pulse winding turns are wound around the stator core teeth.

Among them: the rotor disk 1 is made of non-magnetic material, the inner surface is divided into inner and outer circles, a total of 16 NdFeB permanent magnets 2 and 16 core poles 3 are fixed, all in the shape of a fan, with a gap in the middle, arranged at intervals , that is, the 8 NdFeB permanent magnets 2 and 8 core poles 3 of the same inner ring (or outer ring) are arranged at intervals, and the inner ring and outer ring in the same radial direction fix the NdFeB permanent magnets 2 and core poles respectively 3. The NdFeB permanent magnets are axially magnetized, the magnetization direction of the 8 NdFeB permanent magnets in the outer ring is the same, the magnetization direction of the 8 NdFeB permanent magnets in the inner ring is opposite to that of the outer ring, and the two opposite NdFeB permanent magnets on the two rotors The magnetization direction of the iron boron permanent magnet is the same.

Among them: the stator core 4 is made of silicon steel sheets, the stator teeth and the stator yoke are assembled into a cylindrical shape, and the stator teeth protrude toward the rotor; 8 fan-shaped alnico permanent magnets are fixed at intervals on the 16 stator teeth, forming a 8 stator permanent magnet teeth 5 and 8 stator core teeth 6 are arranged alternately. Stator slots are formed between adjacent stator teeth, the stator three-phase armature concentrated winding 7 and the single-phase pulse winding 8 are placed in the stator slot, the three-phase armature winding 7 turns are wound on the stator core teeth 6, and the single-phase pulse winding 8 turns of the winding are wound on the permanent magnet teeth 5 of the stator.

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

As shown in Figure 2, during the operation of the motor, the NdFeB permanent magnet 2 pasted on the inner surface of the rotor disk 1 generates a constant direction magnetic field, as shown by the solid line closed loop in Figure 2, the constant magnetic flux flows from the outer ring of the rotor disk The (N pole) permanent magnet starts, passes through the air gap, stator teeth, stator yoke, stator teeth, and air gap, and returns to the inner ring of the rotor disc (S pole), thus forming a closed magnetic circuit; and the stator permanent magnet teeth 5 are pasted The magnetization state of the AlNiCo permanent magnet is controlled by the magnitude and direction of the current of the single-phase pulse winding 8 wound on the stator teeth, as shown by the dotted closed loop in Figure 2, the controllable magnetic flux flows from the stator AlNiCo permanent magnet The magnet starts from the stator yoke, the adjacent stator AlNiCo permanent magnet, the air gap, the core pole of the rotor inner ring, the iron core pole of the rotor outer ring, and the air gap, and returns to the AlNiCo permanent magnet, thus forming a controllable magnetic flux Close the magnetic circuit. When the positive pulse current is applied to the single-phase pulse winding to magnetize the AlNiCo permanent magnet so that the magnetization direction is consistent with the magnetic field direction of the NdFeB permanent magnet, the motor reaches the maximum air gap flux density; under light load or When high-speed operation is required, a pulse current in the opposite direction is applied to demagnetize or even reversely magnetize the AlNiCo permanent magnet to reduce or even offset the magnetic flux generated by the NdFeB permanent magnet, thereby achieving the effect of weakening the magnetic field and expanding the speed.

The above is only a preferred embodiment of the present invention, and it should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the principle of the present invention. It should be regarded as the protection scope of the present invention.

Claims (8)

1. the controllable axial magnetic field hybrid permanent magnet memory electrical machine of a kind of magnetic flux, including two rotor disks, stator and installation axles, two Rotor disk is symmetricly set on the both sides of stator, and stator and two rotor disks are co-axially mounted on the mounting shaft；Characterized in that, institute The Nd-Fe-B permanent magnet and pole unshakable in one's determination for being pasted with inside and outside two circles alternate intervals arrangement on the inner surface of rotor disk respectively is stated, wherein, Nd-Fe-B permanent magnet axial charging, the polarity of Nd-Fe-B permanent magnet is consistent on outer ring, on inner ring the polarity of Nd-Fe-B permanent magnet with The opposite polarity of Nd-Fe-B permanent magnet on outer ring, the Nd-Fe-B permanent magnet magnetizing direction of relative position is identical on two rotor disks；

The stator includes stator core, threephase armature winding and monophasic pulses if winding；Stator core is in bilateral symmetry, stator iron Pericardium includes stator yoke and stator tooth, and stator tooth is assembled between cylindric, adjacent stator tooth together with stator yoke and forms stator Groove；Threephase armature winding and monophasic pulses if winding are located in stator slot and circle is around on the stator teeth；

Interval secures Al-Ni-Co permanent magnet on the stator tooth, defines the stator permanent magnet tooth and stator core being alternately arranged Tooth, threephase armature winding turns are wound in stator core tooth, and monophasic pulses if winding turns are wound on stator permanent magnet tooth.

2. a kind of controllable axial magnetic field hybrid permanent magnet memory electrical machine of magnetic flux according to claim 1, it is characterised in that institute State stator core to be made up of silicon steel sheet.

3. a kind of controllable axial magnetic field hybrid permanent magnet memory electrical machine of magnetic flux according to claim 1, it is characterised in that institute The magnetized state for stating Al-Ni-Co permanent magnet is determined by the pulse current size and Orientation of monophasic pulses if winding.

4. a kind of controllable axial magnetic field hybrid permanent magnet memory electrical machine of magnetic flux according to claim 1, it is characterised in that institute Al-Ni-Co permanent magnet is stated in fan shape and for axial charging.

5. a kind of controllable axial magnetic field hybrid permanent magnet memory electrical machine of magnetic flux according to claim 1, it is characterised in that institute State threephase armature winding and monophasic pulses if winding adopts non-overlapped concentratred winding pattern.

6. a kind of controllable axial magnetic field hybrid permanent magnet memory electrical machine of magnetic flux according to claim 1, it is characterised in that institute State Nd-Fe-B permanent magnet identical with the quantity of pole unshakable in one's determination.

7. a kind of controllable axial magnetic field hybrid permanent magnet memory electrical machine of magnetic flux according to claim 1, it is characterised in that institute State rotor disk to be made up of non-magnet material.

8. a kind of controllable axial magnetic field hybrid permanent magnet memory electrical machine of magnetic flux according to claim 1, it is characterised in that institute The shape of Nd-Fe-B permanent magnet and pole unshakable in one's determination is stated in sector, the same radial direction on rotor disk is respectively Nd-Fe-B permanent magnetic Body and pole unshakable in one's determination.