CN108964396B - Stator Partitioned Alternating Pole Hybrid Excitation Motor - Google Patents

Abstract

The invention discloses a stator partitioned alternating-pole hybrid excitation motor, comprising armature windings, excitation windings, permanent magnets, a stator where the armature windings are located, a rotor and a stator where the excitation windings are located. The stator where the armature windings are located and the stator where the excitation windings are located are located on both sides of the rotor. When the stator where the armature windings are located is the outer stator, the stator where the excitation windings are located is the inner stator; when the stator where the excitation windings are located is the outer stator, the armature windings are located on the outer stator. The stator is the inner stator. The number of stator teeth where the armature winding is located is Nst, and the number of stator teeth where the excitation winding is located is Nst/3. The tooth tip of the stator tooth where the excitation winding is located faces the direction of the rotor, and the tooth tip of the stator tooth where each excitation winding is located has one or two permanent magnet poles, and the number of poles formed is 3; The magnetization direction is opposite. While solving the space limitation of the permanent magnet and the armature winding, the invention realizes the effective adjustment of the air-gap magnetic field by arranging a set of excitation windings on the stator.

Description

Stator Partitioned Alternating Pole Hybrid Excitation Motor

technical field

The invention relates to the field of motor manufacturing, in particular to a stator partition type alternating-pole hybrid excitation motor.

Background technique

Permanent magnet motors have the characteristics of simple structure, high efficiency and high power density, and have been widely used in home appliances, electric vehicles, wind power generation, aerospace and other occasions.

According to the different placement of permanent magnets, permanent magnet motors can be divided into rotor permanent magnet type and stator permanent magnet type. As a research hotspot in recent years, the stator permanent magnet motor has permanent magnets and armature windings located on the stator, while the rotor has neither windings nor permanent magnets. Because of its simple structure, reliable operation, easy heat dissipation, and high power density, high efficiency, good fault tolerance and strong load capacity, it has a good application prospect.

However, because the permanent magnets and the armature windings are both arranged on the stator side, there is a geometric conflict between the permanent magnets and the armature windings, which limits the available space for both. Thus, torque density is limited.

Therefore, in 2015, Professor Z. Q. Zhu (Zhu Ziqiang) and others published the paper "Novel electrical machines having separate PMexcitation stator" in IEEE TRANSACTIONS ONMAGNETICS Vol. 51 No. 4 and the paper "Novel doubly salient permanent magnetmachines with Partitioned stator and iron pieces rotor" proposes a stator partitioned stator permanent magnet motor. The armature winding is located on the stator where the armature winding is located, and the permanent magnet is located on the stator where the excitation winding is located, which solves the problem of the space between the armature winding and the permanent magnet. conflict, increasing torque density.

However, because the permanent magnet field is a constant magnetic field, the permanent magnet motor with a partitioned stator also faces an inherent problem of the permanent magnet motor, that is, the limited ability to adjust the magnetic field. This limits the constant power operating range of this type of motor. Although the vector control method can be used to weaken the air gap magnetic field by applying a negative direct-axis current component (-id) in the armature winding, the speed regulation range is very limited due to the limitation of the armature current and the capacity of the inverter. The efficiency and power factor are low in the field weakening speed-up region.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is aimed at the deficiencies of the above-mentioned prior art, and provides a stator partitioned alternating-pole hybrid excitation motor, which can solve the space limitation of permanent magnets and armature windings. At the same time, by setting a set of excitation windings on the stator, the effective adjustment of the air-gap magnetic field is realized.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

A stator partition type alternating-pole hybrid excitation motor comprises armature windings, excitation windings, a stator where the armature windings are located, a rotor, a stator where the excitation windings are located, and a central axis; the rotor is connected with the central axis.

The rotor includes rotor iron core blocks and non-magnetic-conductive blocks arranged alternately in the circumferential direction, and the numbers of the rotor iron-core blocks and the non-magnetic-conductive blocks are equal to the number p of rotor poles.

The stator where the armature winding is located, the stator where the excitation winding is located, and the rotor core block are all made of magnetically conductive materials.

The stator where the armature windings are located and the stator where the excitation windings are located are respectively arranged on both sides of the rotor, there is an air gap 1 between the stator where the armature windings are located and the rotor, and an air gap 2 between the rotor and the stator where the excitation windings are located.

When the stator where the armature winding is located is the outer stator, the stator where the excitation winding is located is the inner stator; when the stator where the excitation winding is located is the outer stator, the stator where the armature winding is located is the inner stator; the number of teeth of the stator where the armature winding is located is Nst, and the excitation The number of teeth of the stator where the windings are located is Nst/3; the currents passing through the excitation coils on the stator teeth where the adjacent excitation windings are located are in opposite directions.

The tooth tip of the stator tooth where the excitation winding is located faces the direction of the rotor. One or two permanent magnets are nested on the tooth tip of the stator tooth where each excitation winding is located to form one or two permanent magnet poles. The tooth tip of the stator where each excitation winding is located The number of poles formed is 3, and the sum of the number of permanent magnet poles and the number of core poles on the stator teeth where all the excitation windings are located is equal to the number of poles Nsp of the stator where the excitation windings are located, and Nsp=Nst; the stator teeth where the adjacent excitation windings are located are permanently The magnets are magnetized in the opposite direction.

A permanent magnet is nested in the middle of the tooth top of the stator tooth where each field winding is located to form a permanent magnet pole. Both sides of the permanent magnet pole are iron core poles; that is, the stator tooth where each field winding is located includes a permanent magnet pole and two Hardcore.

A permanent magnet is nested on both sides of the tooth top of the stator tooth where each excitation winding is located to form two permanent magnet poles, and the stator part between the two permanent magnet poles where the excitation winding is located forms an iron core pole; that is, the stator where each excitation winding is located Each tooth includes two permanent magnet poles and one iron core pole; the magnetization directions of the permanent magnets on the stator teeth where the adjacent excitation windings are located are opposite, and the magnetization directions of the two permanent magnets on the stator teeth where the same excitation winding is located are the same.

Both the armature winding and the field winding are concentrated windings.

The armature winding of each phase is made up of Nst/m coils in series, where m is the number of motor phases.

The excitation winding consists of Nst/3 coils connected in series.

The magnetic flux generated by the excitation winding is carried out through "core pole → air gap 2 → rotor core block → air gap 1 → stator core where the armature winding is located → air gap 1 → rotor core block → air gap 2 → the stator core where the excitation winding is located". closure.

Magnetization is achieved by feeding positive excitation current into the excitation winding; field weakening is achieved by feeding negative excitation current.

The present invention has the following beneficial effects: the present invention provides two excitation sources (permanent magnets and excitation windings) on the stator by arranging a set of excitation windings on the stator. Passing a positive excitation current into the excitation winding can achieve magnetization; passing a negative excitation current into the excitation winding can achieve field weakening. Moreover, the magnetic field (excitation magnetic field) generated by the excitation winding of the present invention does not pass through the permanent magnet, thereby avoiding irreversible demagnetization of the permanent magnet. In addition, the excitation winding is located on the stator, which realizes brushless excitation.

Description of drawings

FIG. 1 shows a first structural diagram of the stator teeth where the excitation windings are located in Embodiment 1 of a stator partitioned alternating-pole hybrid excitation motor.

FIG. 2 shows a second structural diagram of the stator teeth where the excitation windings are located in Embodiment 1 of a stator-partitioned alternating-pole hybrid excitation motor.

FIG. 3 shows a schematic diagram of the magnetic regulation effect of a stator partitioned alternating-pole hybrid excitation motor of the present invention.

Including:

10. The stator where the armature winding is located; 11. The armature winding;

20. The stator where the excitation winding is located; 21. The permanent magnet pole; 22. The excitation winding; 23. The iron core pole;

31. Rotor core; 32. Non-magnetic conductive block.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings and specific preferred embodiments.

Example 1

As shown in Figures 1 and 2, a stator partitioned alternating-pole hybrid excitation motor includes an armature winding 11, an excitation winding 22, a stator 10 where the armature winding is located, a rotor, a stator 20 where the excitation winding is located, and a central axis.

The stator where the armature winding is located and the stator where the excitation winding is located are respectively arranged on both sides of the rotor, the stator where the armature winding is located is an outer stator, and the stator where the excitation winding is located is an inner stator.

There is an air gap 1 between the stator where the armature winding is located and the rotor, and an air gap 2 between the rotor and the stator where the excitation winding is located.

The rotor can be connected with the central shaft through bearings, and the central shaft does not move to form a direct drive motor; the rotor can also be fixedly connected with the central shaft to drive the central shaft to rotate.

The armature winding is preferably wound on the stator teeth where the armature winding is located by centralized winding. Assuming that the number of stator teeth where the armature winding is located is Nst, the armature winding of each phase is formed by Nst/m coils in series, where m is the number of motor phases.

The excitation windings are preferably wound on the stator teeth where the excitation windings are located by centralized winding, and the currents passing through the excitation coils on the stator teeth where the adjacent excitation windings are located are in opposite directions. The excitation winding consists of Nst/3 coils connected in series.

In the present invention, the present invention is described in detail by taking the three-phase motor m=3, Nst=18, and p=17 as an example.

As shown in Figure 1 and Figure 2, there are three-phase armature windings A, B and C on the stator where the armature windings are located; each phase armature winding is formed by 6 coils connected in series, for example, the A-phase windings are connected in series by A1-A6 made. The excitation winding consists of 6 coils connected in series.

The rotor includes rotor core blocks 31 and non-magnetic-conductive blocks 32 that are alternately arranged in the circumferential direction, and the numbers of the rotor-core blocks and the non-magnetic-conductive blocks are both equal to the number p of rotor poles, that is, equal to 17.

The stator where the armature winding is located, the stator where the excitation winding is located, and the rotor core block are all made of magnetically conductive materials.

The number of stator teeth where the excitation winding is located is Nst/3, which is 6.

The tooth tip of the stator tooth where the excitation winding is located faces the direction of the rotor. One or two permanent magnets are nested on the tooth tip of the stator tooth where each excitation winding is located to form one or two permanent magnet poles. The tooth tip of the stator where each excitation winding is located The number of poles formed is 3, and the sum of the number of permanent magnet poles and the number of iron core poles on the stator where all the excitation windings are located is equal to the number of poles Nsp of the stator where the excitation windings are located, and Nsp=Nst; the permanent magnets are preferably radial or parallel magnetized. In this way, the magnetizing directions of the permanent magnets on the stator teeth where the adjacent excitation windings are located are opposite, as shown in Fig. 1 and Fig. 2 , in which the arrows indicate the magnetizing directions.

The number of stator poles of the stator teeth where the excitation winding is located is preferably arranged in the following two ways.

first structure

As shown in Figure 1, a permanent magnet is nested in the middle of the tooth tip of the stator tooth where each excitation winding is located to form a permanent magnet pole, and both sides of the permanent magnet pole are core poles; that is, the stator tooth where each excitation winding is located includes a With one permanent magnet pole 21 and two iron core poles 23, the stator where the excitation winding is located has 6 permanent magnet poles and 12 iron core poles.

second structure

As shown in Figure 2, a permanent magnet is nested on both sides of the tooth top of the stator tooth where each excitation winding is located to form two permanent magnet poles, and the stator part where the excitation winding is located between the two permanent magnet poles forms an iron core pole; that is, The stator tooth where each excitation winding is located includes two permanent magnet poles and one iron core pole; the stator where the excitation winding is located has 12 permanent magnet poles and 6 core poles.

The magnetization directions of the permanent magnets on the stator teeth where the adjacent excitation windings are located are opposite, and the magnetization directions of the two permanent magnets on the stator teeth where the same excitation winding is located are the same.

The field winding's ability to tune the field is limited by the reluctance on its flux path. According to the principle of "minimum reluctance", the magnetic field lines are always closed by the path of least reluctance. Since the reluctance of the permanent magnet is much greater than that of the iron core, the magnetic flux generated by the excitation winding of the present invention does not pass through the permanent magnet, and passes through "core pole → air gap 2 → rotor core block → air gap 1 → the stator core where the armature winding is located. → Air gap 1 → Rotor core block → Air gap 2 → The stator core where the excitation winding is located” is closed. Therefore, the present invention not only has good magnetic regulation ability of magnetic regulation, but also avoids irreversible demagnetization of the permanent magnet caused by the excitation magnetic field.

In addition, by passing a positive excitation current into the excitation winding, the magnetization is realized; the negative excitation current is passed in to realize the weakening.

The present invention has the following beneficial effects:

1. The use of partitioned stator solves the space limitation of permanent magnets and armature windings and improves the torque density.

2. The ability to adjust the magnetization of the excitation winding is limited by the reluctance on its magnetic flux path. According to the principle of "minimum reluctance", the magnetic field lines are always closed by the path of least reluctance. Since the reluctance of the permanent magnet is much greater than that of the iron core, the magnetic flux generated by the excitation winding of the present invention does not pass through the permanent magnet, and passes through "core pole → air gap 2 → rotor core block → air gap 1 → the stator core where the armature winding is located. → Air gap 1 → Rotor core block → Air gap 2 → The stator core where the excitation winding is located” is closed. Therefore, the present invention not only has good magnetic regulation ability of magnetic regulation, but also avoids irreversible demagnetization of the permanent magnet caused by the excitation magnetic field.

3. By applying positive excitation current (magnetization) and negative excitation current (weakening), the adjustment effect of its no-load back EMF is shown in Figure 3.

3. The stator where the excitation winding of the present invention is located, although the permanent magnet poles and the iron core poles are arranged alternately, contains permanent magnets with opposite magnetization directions, so there is no problem of unipolar flux leakage and magnetization of mechanical parts.

4. The excitation winding is located on the stator, which realizes the brushless excitation.

5. The motor of the present invention can be used for both electric operation and power generation operation.

Example 2

Embodiment 2 is basically the same as Embodiment 1, except that the structure of the stator where the excitation winding is located is exchanged with that of the stator where the armature winding is located. That is, the stator where the excitation winding is located is the outer stator, and the stator where the armature winding is located is the inner stator.

At this time, the specific structure of the stator teeth where the excitation winding is located is the same as that of the first embodiment, and will not be repeated here.

The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention. These equivalent transformations All belong to the protection scope of the present invention.

Claims (7)

1. A stator partition type alternate pole hybrid excitation motor comprises an armature winding, an excitation winding, an outer stator, a rotor, an inner stator and a rotating shaft, wherein the outer stator, the rotor, the inner stator and the rotating shaft are coaxially arranged from outside to inside in sequence; an outer gap is formed between the outer stator and the rotor, an inner gap is formed between the rotor and the inner stator, and the rotor is fixedly connected with the rotating shaft; the method is characterized in that: the armature winding is wound on the outer stator teeth, the excitation winding is wound on the inner stator teeth, and the directions of currents introduced into the excitation windings on the adjacent inner stator teeth are opposite;

the rotor comprises rotor iron core blocks and non-magnetic conducting blocks which are circumferentially and alternately arranged, and the number of the rotor iron core blocks and the number of the non-magnetic conducting blocks are equal to the number p of rotor poles;

the outer stator, the inner stator and the rotor iron core block are all made of magnetic materials;

the number of outer stator teeth is Nst,

the number of the inner stator teeth is Nst/3, the tooth tops of the inner stator teeth face the direction of the rotor, one or two permanent magnets are nested on the tooth tops of the inner stator teeth to form one or two permanent magnet poles, the number of poles of each inner stator tooth is 3, the sum of the number of all the permanent magnet poles on the inner stator and the number of all the iron core poles is equal to the number of poles Nsp of the inner stator, and the number of poles Nsp = Nst of the inner stator; the magnetizing directions of the permanent magnets on the adjacent inner stator teeth are opposite;

the magnetic flux generated by the field winding is closed by the "core pole → inner air gap → rotor core block → outer air gap → outer stator core → outer air gap → rotor core block → inner air gap → inner stator core".

2. The stator-partitioned alternating-pole hybrid excitation motor according to claim 1, characterized in that: the middle part of the tooth top of each inner stator tooth is respectively nested with a permanent magnet to form a permanent magnet pole, and the two sides of the permanent magnet pole are iron core poles; i.e. each inner stator tooth comprises one permanent magnet pole and two core poles.

3. The stator-partitioned alternating-pole hybrid excitation motor according to claim 1, characterized in that: two permanent magnets are respectively nested at two sides of the tooth top of each inner stator tooth to form two permanent magnet poles, and an iron core pole is formed at the inner stator part between the two permanent magnet poles; that is, each inner stator tooth comprises two permanent magnet poles and an iron core pole; the magnetizing directions of the permanent magnets on the adjacent inner stator teeth are opposite, and the magnetizing directions of the two permanent magnets on the same inner stator tooth are the same.

4. The stator-partitioned alternating-pole hybrid excitation motor according to claim 1, characterized in that: the armature winding and the excitation winding both adopt concentrated windings.

5. The stator-partitioned alternating-pole hybrid excitation motor according to claim 4, characterized in that: each phase of armature winding is formed by connecting Nst/m coils in series, wherein m is the number of motor phases.

6. The stator-partitioned alternating-pole hybrid excitation motor according to claim 4, characterized in that: the excitation winding is formed by connecting Nst/3 coils in series.

7. The stator-partitioned alternating-pole hybrid excitation motor according to claim 1, characterized in that: the positive exciting current is introduced into the exciting winding to realize the magnetization increase; and negative exciting current is introduced to realize field weakening.

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