CN107453573A - A kind of not equidistant mixed excitation bisalient-pole permanent-magnet synchronous machine of stator poles - Google Patents

Abstract

The invention belongs to the field of double salient pole permanent magnet synchronous motors, and discloses a mixed excitation double salient pole permanent magnet synchronous motor with unequal spacing between stator poles. It includes stator, rotor, shaft, permanent magnets, DC field winding and three-phase AC armature winding. The stator is spliced by multiple modules; the DC excitation winding is set in the slot between the two stator poles of the same module; the rotor is equipped with evenly distributed salient pole structure rotor poles; the permanent magnet is set between the adjacent modules The space is used to generate the air gap magnetic field between the stator and the rotor; the rotating shaft is arranged inside the rotor; the AC armature winding is arranged in the slot between adjacent stator poles of different modules. Through the invention, the DC excitation winding can be used to adjust the size of the air gap magnetic field, thereby adjusting the counter electromotive force generated in the armature winding when the motor runs at high speed, and further expanding the constant power operating range of the motor.

Description

A Hybrid Excited Doubly Salient Permanent Magnet Synchronous Motor with Unequal Stator Pole Spacing

technical field

The invention belongs to the field of double salient pole permanent magnet synchronous motors, and more specifically relates to a hybrid excitation double salient pole permanent magnet synchronous motor with unequal spacing between stator poles.

Background technique

In recent years, doubly salient permanent magnet motors in which the stator poles and rotor poles are salient poles have been extensively studied. The doubly salient permanent magnet synchronous motors in the prior art can obtain bipolar flux linkages, which can greatly improve the Torque and power density of the motor.

If the air-gap magnetic field of the doubly salient permanent magnet synchronous motor is completely generated by permanent magnets, the air-gap magnetic field is difficult to adjust. When the motor operates in a high speed range, a high back EMF will be induced in the AC armature winding; When the potential is higher than the power supply voltage, the energy cannot be input into the motor from the power supply, so that the motor cannot be maintained at this speed. Shortcomings such as poor speed ability. Although a hybrid excitation doubly salient permanent magnet synchronous motor has been proposed in the prior art to improve its magnetic field weakening performance, the flux linkage interlinked with its AC armature winding is unipolar (causing a small torque density) or its DC excitation The slot area occupied by the winding is extremely limited (due to the limitation of its own structure), so it is difficult to give full play to its magnetic modulation performance and solve the field-weakening speed regulation problem of the double salient permanent magnet synchronous motor.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the present invention provides a hybrid excitation double salient pole permanent magnet synchronous motor with unequal spacing between stator poles, by adopting multi-phase AC windings and two sets of DC excitation windings, wherein by controlling the DC The direction and magnitude of the current in the excitation winding can adjust the magnetic field generated by it, and then interact with the magnetic field generated by the permanent magnet to increase or weaken the air gap magnetic field. At the same time, the stator poles are set at unequal intervals, and the DC excitation is adjusted through optimal design. The ratio of the slot area occupied by the winding and the AC armature winding increases the adjustment ability of the air gap magnetic field of the motor, thereby solving the technical problems of poor magnetic field weakening capability and narrow speed regulation range of the double salient permanent magnet synchronous motor.

In order to achieve the above object, according to the present invention, a hybrid excitation double salient pole permanent magnet synchronous motor with unequal stator spacing is provided. is that

The stator is arranged on the outside of the rotor, and the stator is spliced by a plurality of identical modules, and each module is provided with an included angle of The two salient stator poles of , the angle between adjacent stator poles in different modules is θ, where, is not equal to θ, thereby forming stator poles with unequal spacing; in addition, the permanent magnets are arranged between adjacent modules; the adjacent stator poles in the same module are provided with the DC excitation windings, the AC armature windings are arranged on adjacent stator poles in different modules, and all the AC armature windings form an AC winding set, and multiple phases are connected to the AC armature windings in the AC winding set current;

The rotor is arranged on the rotating shaft, and a plurality of rotor poles with a salient pole structure are evenly distributed on the outer circumference of the rotor, and the rotor poles are arranged opposite to the stator poles.

Further preferably, currents of various phases are fed into the AC armature winding, and the phase angle δ between each current is performed according to the following expression,

Wherein, m is the number of current phases passed in, and m is a positive integer greater than or equal to 3.

Further preferably, the magnetization directions of adjacent permanent magnets are opposite.

Further preferably, the relationship among the stator poles, rotor poles and phase numbers is carried out according to the following expressions,

Among them, N _s represents the number of poles of the stator, N _r represents the number of poles of the rotor, and k is any integer.

Further preferably, the included angle The relationship between and θ is carried out according to the following expression,

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

1. The present invention adopts multi-phase AC armature windings, and the phase difference between the currents (sine waves or square waves) of different phase windings is 360/m (m is the phase number of the motor) electrical angle, so that higher rotational speed can be obtained. Moment density and starting torque, and improve the reliability of the motor;

2. The motor of the present invention is provided with a DC excitation winding, which can realize the adjustment of the air gap magnetic field of the motor by controlling the magnitude and direction of the current in the DC excitation winding, thereby improving the field-weakening speed expansion capability of the motor and expanding its constant power operating range ;

3. The slot area occupied by the multi-phase armature winding and the DC field winding of the motor according to the present invention can be distributed by adjusting the angle between the two stator poles on the same module, so as to ensure that the DC field winding has a relatively Large slot area and high number of turns ensure that it has a strong magnetic field adjustment capability, enabling the motor to obtain stronger magnetic field-weakening speed expansion capabilities;

4. The present invention simplifies the product structure by integrating the stator, rotor, rotating shaft, permanent magnet and armature winding into one body, making the overall structure of the motor more compact, and has the characteristics of ingenious overall layout, convenient operation and use, etc. .

Description of drawings

Fig. 1 is a schematic structural view of a three-phase, 12-slot, 5-pole stator pole with unequal spacing hybrid excitation double salient pole permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention;

Fig. 2 is a structural schematic diagram of a three-phase, 12-slot, 8-pole stator pole with unequal spacing hybrid excitation double salient pole permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention;

Fig. 3 is a structural schematic diagram of a hybrid excitation double salient pole permanent magnet synchronous motor with unequal spacing between five-phase, 20-slot, 12-pole stator poles constructed according to a preferred embodiment of the present invention;

Fig. 4 is a three-phase 12-slot 5-pole stator pole unequal spacing hybrid excitation double salient permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention, when the excitation current is zero, the flux linkage generated in the A-phase AC armature winding Curve;

Fig. 5 is a three-phase 12-slot 5-pole stator pole with unequal spacing hybrid excitation double salient pole permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention. The generated flux linkage change curve;

Fig. 6 is a no-load flux variation curve of a three-phase, 12-slot, 5-pole stator pole with unequal spacing hybrid excitation double salient pole permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention under different excitation currents.

Throughout the drawings, the same reference numerals are used to designate the same elements or structures, wherein:

1-Stator 2-Permanent magnet 3-Rotor 4, 5, 6-A, B, C three-phase AC armature winding 7-DC excitation winding 8-rotating shaft 9-D-phase AC armature winding 10-E-phase AC armature winding

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

Below in conjunction with a preferred embodiment of the present invention, Fig. 1 is a structural schematic diagram of a three-phase, 12-slot, 5-pole stator pole with unequal spacing hybrid excitation double salient permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention, Fig. 2 It is a structural schematic diagram of a three-phase, 12-slot, 8-pole stator pole with unequal spacing hybrid excitation double salient pole permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention. Fig. 3 is a five-phase motor constructed according to a preferred embodiment of the present invention Schematic diagram of the structure of a hybrid excitation double salient pole permanent magnet synchronous motor with 20 slots and 12 poles with unequal spacing between stator poles. Stator 1, rotor 3, rotating shaft 8, permanent magnet 2, three-phase AC armature windings 4, 5, 6 and DC field winding 7.

The stator 1 is spliced by multiple identical modules, each module is a "π"-shaped iron core, and the angle between the two stator poles on the same "π"-shaped iron core is The angle θ between the two stator poles on the adjacent "π"-shaped iron core is not equal, so the stator poles are unevenly distributed on the stator circumference; the permanent magnet 2 is arranged between two adjacent "π"-shaped iron cores, The magnetization direction of permanent magnets is along the circumferential direction, and the magnetization directions of adjacent permanent magnets are opposite; The winding 7 is arranged in the slot between two stator poles of adjacent "π" type iron cores;

The rotor 3 is provided with evenly distributed rotor poles with a plurality of salient pole structures; the rotating shaft 8 is arranged inside the rotor. When the AC armature winding is fed with current, the magnetic field generated by the AC armature winding interacts with the magnetic field generated by the permanent magnet and the DC field winding. function, so that the rotor 3 and the rotating shaft 8 can rotate relative to the stator.

The permanent magnet 2 is arranged between two adjacent "π" type iron cores, the permanent magnet is magnetized along the circumferential direction, and the magnetization directions of the two adjacent permanent magnets are opposite.

The three-phase AC armature windings 4, 5, 6 are set in the slot between the two stator poles of the same "π"-shaped iron core, and the DC field winding 7 is set in the two stator poles of the adjacent "π"-shaped iron core in the slot between.

For the number of stator poles, rotor poles and phases of the motor, the following relationship (1) is preferably adopted:

Among them, N _s represents the number of stator poles, N _r represents the number of rotor poles, m represents the number of phases, and k is any integer.

The angle between two stator poles on adjacent "π"-shaped iron cores is θ, and the angle between two stator poles on the same "π"-shaped iron core is where θ is less than any value of .

In order to fully describe the working principle of the motor of the present invention, to reflect the characteristics of the motor of the present invention, the following motor parameters (shown in Table 1) have been designed, and relevant analysis has been carried out:

Table 1 Main parameters of the motor

In order to fully illustrate the working principle of the hybrid excitation doubly salient permanent magnet synchronous motor of the present invention and its field-weakening effect, the motor with the structural parameters shown in Table 1 is modeled by finite element, and analyzed to obtain the current when the field winding does not pass into it. The change curve of phase A no-load flux linkage with the electric angle of the rotor position, Fig. 4 is a three-phase 12-slot 5-pole stator pole with unequal spacing hybrid excitation double salient pole permanent magnet synchronous motor constructed according to the preferred embodiment of the present invention in excitation When the current is zero, the flux linkage change curve produced in the A-phase AC armature winding is shown in Figure 4. The hybrid excitation double salient permanent magnet synchronous motor of the present invention can be in the AC armature winding when only the permanent magnets are excited. A more sinusoidal flux linkage is generated, so that a more sinusoidal back EMF can be induced, and its amplitude is about 0.1234Wb.

Fig. 5 is a three-phase 12-slot 5-pole stator pole with unequal spacing hybrid excitation double salient pole permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention. The generated flux linkage change curve is shown in FIG. 5 , when only the DC excitation winding 7 is excited, the change curve of the no-load flux linkage in the A-phase AC armature winding with the electrical angle of the rotor position. It can be seen from Figure 5 that when a forward excitation current of 50A is passed into the DC excitation winding, the magnetic flux generated in the A-phase AC armature winding is close to a sine wave, and its amplitude is about 0.0340Wb. When the reverse excitation current of 100A is passed into the DC excitation winding, the flux linkage of the opposite phase can be generated in the A-phase AC armature winding, but it is still close to a sine wave, and its amplitude is about 0.0681Wb.

Fig. 6 is a three-phase, 12-slot, 5-pole stator pole with unequal spacing hybrid excitation double salient pole permanent magnet synchronous motor constructed according to a preferred embodiment of the present invention. The no-load flux linkage variation curve under different excitation currents, as shown in Fig. 6 , when the permanent magnet 2 and the DC excitation winding 7 act at the same time, the change curve of the no-load permanent magnet flux linkage in the A-phase AC armature winding with the electrical angle of the rotor position. It can be seen from Figure 6 that when the excitation current of -100A is passed into the DC excitation winding, the no-load magnetic chain generated in the AC armature winding of phase A is close to a sine wave, and its amplitude is about 0.0547Wb; when the DC excitation winding 7 When the excitation current of 50A is passed through, the no-load flux linkage generated in the A-phase AC armature winding is a sine wave with an amplitude of 0.1414Wb. Therefore, by controlling the size and direction of the current in the DC excitation winding, the strength of the air-gap magnetic field can be adjusted, and then the magnitude of the flux linkage generated in the A-phase AC armature winding can be adjusted. Therefore, the hybrid excitation double salient pole permanent magnet synchronous motor of the present invention It has a strong magnetic field adjustment capability, which can greatly improve the motor's field-weakening speed expansion capability and broaden its constant power operating range.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (5)

1. a kind of not equidistant mixed excitation bisalient-pole permanent-magnet synchronous machine of stator, the motor include stator (1), rotor (3), Permanent magnet (2), exchange armature winding, DC excitation winding (7) and rotating shaft (8), it is characterised in that

The stator (1) is arranged on the outside of the rotor, and the stator is spliced by multiple identical modules, in each module Being provided with angle isTwo salient pole stator poles, the angle in disparate modules between adjacent stator poles is θ, wherein,With θ is unequal, is consequently formed not equidistant stator poles；In addition, it is provided with the permanent magnet between the adjacent module (2)；The DC excitation winding (7) is provided with adjacent stator pole in the same module, in the different modules The exchange armature winding is provided with adjacent stator pole, all exchange armature winding forms exchange winding collection, should The electric current of a variety of phases is passed through on exchange armature winding in exchange winding collection；

The rotor (3) is arranged in the rotating shaft (8), and equally distributed multiple salient pole knots are provided with the excircle of the rotor The rotor pole of structure, and the rotor pole is oppositely arranged with the stator poles.

2. a kind of not equidistant mixed excitation bisalient-pole permanent-magnet synchronous machine of stator as claimed in claim 1, its feature exist In being passed through the electric currents of a variety of phases on the exchange armature winding, the phase angle δ between each electric current reaches according to following table Formula is carried out,

Wherein, m is the electric current number of phases being passed through, and m is greater than or equal to 3 positive integer.

3. a kind of not equidistant mixed excitation bisalient-pole permanent-magnet synchronous machine of stator poles as claimed in claim 1 or 2, it is special Sign is that the direction of magnetization of the adjacent permanent magnet (2) is opposite.

4. a kind of not equidistant mixed excitation bisalient-pole permanent-magnet synchronous machine of stator as claimed in claim 2, its feature exist In, the relation between the stator poles, rotor pole and the number of phases is carried out according to following expression formula,

<mrow> <mfrac> <msub> <mi>N</mi> <mi>s</mi> </msub> <msub> <mi>N</mi> <mi>r</mi> </msub> </mfrac> <mo>=</mo> <mfrac> <mrow> <mn>4</mn> <mi>m</mi> </mrow> <mrow> <mn>4</mn> <mi>m</mi> <mo>&amp;PlusMinus;</mo> <mi>k</mi> </mrow> </mfrac> </mrow>

Wherein, N_sRepresent stator poles, N_rRotor number of poles is represented, k is arbitrary integer.

5. the not equidistant mixed excitation bisalient-pole permanent-magnet synchronous machine of a kind of stator as described in claim any one of 1-4, Characterized in that, the angleRelation between θ is carried out according to following expression formula,