Axial magnetic field hybrid excitation synchronous motor based on L-shaped magnetic conductor

Abstract

The embodiment of the application discloses an axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor, and relates to the technical field of hybrid excitation motors.The application comprises a stationary annular magnetic bridge and a direct-current excitation winding, a stator core and an armature winding, a rotating L-shaped magnetic conductor and a Halbach permanent magnet.Two rotating components are installed on a non-magnetic rotor disc and rotate with a rotating shaft.The hybrid excitation motor adopts an annular magnetic bridge structure, so that the excitation winding can be installed on the stator, and the L-shaped magnetic bridge structure makes the electric excitation magnetic circuit axially closed, thereby meeting the brushless requirement;the permanent magnet magnetic circuit and the electric excitation magnetic circuit are axially connected in parallel, the irreversible demagnetization risk of the permanent magnet is reduced, and the power density and the operation reliability are further improved.

Description

Technical Field

[0001] This invention relates to the field of hybrid excitation motor design technology, and more particularly to an axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor. Background Technology

[0002] Traditional permanent magnet motors use permanent magnets as the excitation source. The high energy product of permanent magnets gives permanent magnet motors advantages such as high power density and high efficiency. However, a single excitation source leads to inherent problems with permanent magnet motors, such as difficulty in magnetic field regulation and fault demagnetization, limiting the expansion of the high-efficiency operating range, voltage regulation during generation, and fault protection capabilities. Introducing an electric excitation source allows the air gap magnetic field to be generated simultaneously by two excitation sources. The air gap magnetic field can be adjusted by regulating the excitation current. The ratio of the electric excitation magnetomotive force (EMF) to the permanent magnet MMF directly reflects the motor's magnetomotive force regulation capability. Based on the placement of the permanent magnets, hybrid excitation motors can be divided into rotor permanent magnet hybrid excitation motors and stator permanent magnet hybrid excitation motors. Among them, rotor permanent magnet hybrid excitation motors have relatively higher power density and efficiency, and have received widespread attention and application. For hybrid excitation motors, if the electric excitation winding is directly wound on the rotor of a permanent magnet motor, it will form a series hybrid excitation magnetic circuit through which the electric excitation magnetic circuit passes. This increases the total magnetic reluctance of the magnetic circuit and poses a greater risk of irreversible demagnetization of the permanent magnet. At the same time, the electric excitation winding on the rotor requires brushes and slip rings to construct the electric excitation magnetic field. Mechanical wear and commutation sparks caused by the mechanical commutator will limit the motor's operating speed range and reliability.

[0003] Therefore, a brushless hybrid excitation motor topology is key to achieving high-reliability motor operation. Positioning the excitation winding on the stator facilitates brushless excitation, and a special magnetic conductive structure allows for the organic integration of the electrically excited magnetic circuit and the permanent magnet magnetic circuit. The requirement for brushless operation presents challenges to the construction of the electrically excited magnetic circuit and the improvement of excitation efficiency.

[0004] In summary, the new direction for permanent magnet motor structural design is to meet the requirements of brushless operation while maintaining the parallel relationship between the permanent magnet circuit and the electrically excited circuit, and to ensure that the electrically excited circuit does not pass through the permanent magnet, thereby reducing the risk of irreversible demagnetization of the permanent magnet and improving operational reliability. Summary of the Invention

[0005] The embodiments of the present invention provide an axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor, which can meet the requirements of brushless operation and realize the axial parallel connection of permanent magnet circuit and electric excitation circuit. At the same time, it can also reduce the risk of irreversible demagnetization of permanent magnet by eliminating the passage of electric excitation circuit through permanent magnet, thereby further improving operational reliability.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] Main shaft (1), stator core (2), armature winding (3), rotor disk (4), Halbach permanent magnet array (5), L-shaped magnetic conductor (7), ring magnetic bridge (6) and excitation winding (8);

[0008] The armature winding (3) is a stationary component, wound on the axial teeth of the stator core (2);

[0009] Halbach permanent magnet array (5) and L-shaped magnetic bridge (7) are fixed on rotor disk (4), rotor disk (4) is fixed on main shaft (1), and is supported by bearings on both sides of rotor disk (4) on main shaft (1) to form a rotating component;

[0010] The excitation winding (8) is embedded in the annular magnetic bridge (6), which is fixed on the end cover and is a stationary component, thereby realizing brushless excitation;

[0011] The magnetic circuit formed after the motor is powered on includes two parts: permanent magnet circuit and electric excitation circuit. The permanent magnet flux path sequence is: Halbach permanent magnet array (5) → rotor disk (4) → working air gap 2 → stator core (2) → working air gap 2 → rotor disk (4) → Halbach permanent magnet array (5).

[0012] The sequence of the electromagnetic flux path is as follows: annular magnetic bridge (6) → working air gap 1 → N-pole L-shaped magnetic conductor → rotor disk (4) → working air gap 2 → stator core (2) → working air gap 2 → rotor disk (4) → S-pole L-shaped magnetic conductor → working air gap 1 → annular magnetic bridge (6).

[0013] The stator core (2) includes a stator back yoke and axial stator teeth (10). The stator slots formed are straight slots. The armature winding (3) is wound on the axial stator teeth (10), and a slot wedge or pole shoe or other structure is used to fix the winding.

[0014] The rotor disk (4) is a thin disc made of non-magnetic material with high structural strength. Specifically, the non-magnetic rotor disk can be made of 3Cr13 stainless steel. The L-shaped magnetic conductor (7) and the Halbach permanent magnet array (5) are fixedly mounted on the rotor disk (4) so ​​that the rotor disk (4) rotates with the main shaft (1) when the main shaft (1) rotates, while the L-shaped magnetic conductor (7) and the Halbach permanent magnet array (5) rotate with the rotor disk (4). By fixing the L-shaped magnetic conductor and the Halbach permanent magnet array on the rotor disk, the three components rotate simultaneously with the main shaft.

[0015] The L-shaped magnetic conductor (7) is divided into two sections along the axial and radial directions. The cross-sectional shape of the axial section is a fan ring. According to the inner and outer radius dimensions and installation direction of the fan ring of the axial section, the structure of the L-shaped magnetic conductor (7) is divided into a first type of magnetic conductor structure and a second type of magnetic conductor structure. The first type of magnetic conductor structure and the second type of magnetic conductor structure are arranged alternately along the circumference of the annular magnetic bridge (6), and the gap between each two adjacent magnetic conductors is evenly distributed. Specifically, there are multiple gaps in the motor structure, which can be divided into effective air gaps and ordinary gaps according to whether there is a main magnetic flux passing through them. The gaps with main magnetic flux passing through are effective air gaps, and the gaps without main magnetic flux passing through them are ordinary gaps. The first type of magnetic conductor structure includes: the inner radius and outer radius of the cross-section of the axial section are the same as the inner ring radius and outer ring radius of the inner ring of the annular magnetic bridge (6), respectively. The second type of magnetic conductor structure includes: the inner radius and outer radius of the cross-section of the axial section are the same as the inner ring radius and outer ring radius of the outer ring of the annular magnetic bridge (6), respectively.

[0016] The annular magnetic bridge (6) is made of magnetically conductive material. Specifically, the magnetically conductive material can be No. 10 steel, 1J22 iron-cobalt-vanadium soft magnetic alloy, etc. The structure of the annular magnetic bridge (6) includes a base plate and two annular sidewalls. The dimensions of the two annular sidewalls are constrained by the L-shaped magnetic conductor. In order to increase the cross-sectional area of ​​the electric excitation magnetic circuit, the inner and outer diameters of the two annular walls are the same as the inner and outer diameters of the axial section of the L-shaped magnetic conductor. The excitation winding (8) is embedded and fixed in the annular groove formed by the base plate and the two annular sidewalls. The excitation winding (8) adopts DC excitation.

[0017] In the Halbach permanent magnet array (5), each pair of poles is composed of several permanent magnets with different magnetization directions; the number of pole pairs of the Halbach permanent magnet array (5) determines the number of pole pairs of the motor.

[0018] The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor provided in this invention has a stationary annular magnetic bridge and DC excitation winding, a stator core and armature winding, and a rotating L-shaped magnetic conductor and Halbach permanent magnet. Two rotating components are mounted on a non-magnetic rotor disk and rotate with the shaft. This hybrid excitation motor uses an annular magnetic bridge structure, allowing the excitation winding to be mounted on the stator. Combined with the L-shaped magnetic bridge structure, the electrical excitation circuit is axially closed, meeting the requirements for brushless operation. Its permanent magnet circuit and electrical excitation circuit are axially paralleled, reducing the risk of irreversible demagnetization of the permanent magnet and further improving operational reliability. Furthermore, the above design also has a high power density, possessing certain design advantages. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is an exploded topology diagram of the axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to the present invention.

[0021] Figure 2 This invention relates to the overall structural topology of the axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor.

[0022] Figure 3 This is a schematic diagram of the magnetic circuit of the axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to the present invention;

[0023] Figure 4 This is a schematic diagram of the stator core structure according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the magnetization direction of a pair of permanent magnets under a pole in a Halbach permanent magnet array according to an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the back structure of the L-shaped magnetic conductor according to an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the air gaps at various points in the motor according to an embodiment of the present invention;

[0027] Explanation of component symbols in the figure: 1-Main shaft; 2-Stator; 3-Armature winding; 4-Rotor disk; 5-Halbach permanent magnet array; 6-Annular magnetic bridge; 7-L-shaped magnetic conductor; 8-Excitation winding; 9-Stator back yoke; 10-Axial stator teeth; 11-Stator slot. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0029] The electric excitation source of the axial magnetic field hybrid excitation synchronous motor based on the L-shaped magnetic conductor proposed in this embodiment is located on the stationary component, which can meet the brushless requirement. Moreover, the permanent magnet circuit and the electric excitation circuit are connected in parallel. The electric excitation circuit does not pass through the permanent magnet, which has a stronger magnetic field regulation capability.

[0030] like Figure 1 As shown, this embodiment provides an axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor, including a main shaft 1, a stator core 2, an armature winding 3, a rotor disk 4, a Halbach permanent magnet array 5, an L-shaped magnetic conductor 7, an annular magnetic bridge 6, and an excitation winding 8. Combined with... Figure 2The armature winding 3 is wound on the axial teeth of the stator core 2; the Halbach permanent magnet array 5 surrounds the outside of the L-shaped magnetic bridge 7, and both are fixed on the rotor disk 4. The rotor disk 4 is fixed on the main shaft 1 and is supported by bearings on both sides to form a rotating component; the excitation winding 8 is embedded in the annular magnetic bridge 6, and the annular magnetic bridge 6 is fixed on the end cover, thereby realizing brushless excitation; wherein the rotor disk 4, Halbach permanent magnet array 5, and L-shaped magnetic bridge 7 are rotating components, and the stator core 2, armature winding 3, annular magnetic bridge 6, and excitation winding 8 are stationary components.

[0031] like Figure 3 As shown, the total magnetic circuit of the axial hybrid excitation synchronous motor based on the L-shaped magnetic conductor 7 includes two parts: a permanent magnet circuit and an electrically excited magnetic circuit. The permanent magnet flux path is: Halbach permanent magnet array 5 → rotor disk 4 → air gap → stator core 2 → air gap → rotor disk 4 → Halbach permanent magnet array 5; the electrically excited flux path is: annular magnetic bridge 6 → air gap → N-pole L-shaped magnetic conductor → rotor disk 4 → air gap → stator core 2 → air gap → rotor disk 4 → S-pole L-shaped magnetic conductor → air gap → annular magnetic bridge 6.

[0032] Furthermore, the stator core comprises two parts: a stator back yoke and axial stator teeth. Different motor output performances can be obtained by optimizing the stator tooth profile. As a specific example, the formed stator slots are straight slots, with a total of 12 slots. The armature winding is wound on the stator teeth, and structures such as slot wedges or pole shoes can be used to fix the winding.

[0033] Furthermore, the annular magnetic bridge 6 includes a base plate and two annular sidewalls, the thickness of which is designed to be related to the magnetomotive force of the excitation winding. The excitation winding is embedded in the annular groove formed by the base plate and the sidewalls, and uses DC excitation. The range of variation of the DC excitation magnetomotive force affects the motor's magnetic adjustment capability. Fixing the annular magnetic bridge to the end cover facilitates heat dissipation from the excitation winding.

[0034] like Figure 4 As shown, the stator core includes a stator back yoke and axial stator teeth, and the resulting stator slots are straight slots.

[0035] In the motor topology, the N and S poles are combined to form a pole pair. The Halbach array selects the number of permanent magnets and the magnetization direction based on the specific magnetization effect. Specifically, as follows... Figure 5 As shown, each pole pair of the Halbach permanent magnet array 5 consists of several permanent magnets with different magnetization directions. The number of pole pairs in the Halbach permanent magnet array is equal to the number of pole pairs in the motor. As a specific example, this axial hybrid excitation motor uses 10 pole pairs, with each pole pair corresponding to a central angle of 36°. Figure 4The magnetization directions of the five permanent magnets under each pair of poles are shown. The magnetization direction of the first permanent magnet is 0°, the magnetization direction of the second permanent magnet changes 90° counterclockwise, and so on.

[0036] like Figure 6 As shown, the L-shaped magnetic conductor 7 can be divided into two segments along the axial and radial directions. The cross-sectional shape of the axial segment is a fan-shaped ring. Based on the inner and outer radii of the fan-shaped ring and the installation direction, the L-shaped magnetic conductors can be divided into two categories. The inner and outer radii R1 and R2 of the axial cross-section of the first type of magnetic conductor correspond to the radii of the inner ring of the annular magnetic bridge, respectively. The inner and outer radii R3 and R4 of the axial cross-section of the second type of magnetic conductor correspond to the radii of the outer ring of the annular magnetic bridge, respectively. The two types of L-shaped magnetic conductors are arranged alternately along the circumference of the annular magnetic bridge. As a specific example, the gap between every two magnetic conductors is uniformly distributed.

[0037] like Figure 7 As shown, there are multiple air gaps in the motor structure. According to the "principle of minimum magnetic reluctance," the dimensional constraints of these gaps affect the direction of the electromagnetic flux. The air gaps satisfy the following dimensional relationship equation.

[0038] min{σ3,σ4}≥5max{σ1,σ2}

[0039] In the formula, σ1 is the axial distance from the stator teeth to the top surface of the L-shaped magnetic conductor, σ2 is the axial distance from the bottom surface of the L-shaped magnetic conductor to the top boundary of the annular magnetic conductor, σ3 is the axial distance between the top surface of the annular magnetic bridge and the bottom surface of the radial section of the L-shaped magnetic conductor, and σ4 is the circumferential distance between the two types of L-shaped magnetic conductors.

[0040] The main advantages of this embodiment in practical applications are as follows: The use of a Halbach permanent magnet array provides excellent magnetic focusing, increasing the motor's power density; the parallel magnetic circuit reduces the risk of demagnetization of the permanent magnets, improving the motor's magnetic field regulation capability and reliability; the ring-shaped magnetic bridge structure positions the excitation winding on the stator, and the L-shaped magnetic bridge structure ensures axial closure of the electrical excitation magnetic circuit, meeting brushless requirements and further enhancing the motor's operational reliability; the L-shaped magnetic bridge structure allows the electrical excitation magnetic field to be equivalent to a rotor-excited rotating magnetic field, further increasing the motor's power density.

[0041] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A synchronous motor with hybrid axial magnetic field excitation based on an L-shaped magnetic conductor, characterized in that, include: Main shaft (1), stator core (2), armature winding (3), rotor disk (4), Halbach permanent magnet array (5), L-shaped magnetic conductor (7), ring magnetic bridge (6) and excitation winding (8); The armature winding (3) is wound on the axial teeth of the stator core (2); Halbach permanent magnet array (5) and L-shaped magnetic bridge (7) are fixed on rotor disk (4), rotor disk (4) is fixed on main shaft (1), and is supported by bearings on main shaft (1) to form a rotating component; The excitation winding (8) is embedded in the annular magnetic bridge (6), and the annular magnetic bridge (6) is fixed on the end cover; The magnetic circuit formed after the motor is energized consists of two parts: the permanent magnet magnetic circuit and the electrically excited magnetic circuit. The L-shaped magnetic conductor (7) is divided into two sections along the axial and radial directions, wherein the cross-sectional shape of the axial section is a fan ring; According to the inner and outer radius dimensions and installation direction of the fan ring of the axial section, the structure of the L-shaped magnetic conductor (7) is divided into the first type of magnetic conductor structure and the second type of magnetic conductor structure; The first type of magnetic conductor structure and the second type of magnetic conductor structure are arranged alternately along the circumference of the annular magnetic bridge (6), and the gap between each two adjacent magnetic conductors is evenly distributed.

2. The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to claim 1, characterized in that, The permanent magnet flux path sequence is as follows: Halbach permanent magnet array (5) → rotor disk (4) → working air gap 2 → stator core (2) → working air gap 2 → rotor disk (4) → Halbach permanent magnet array (5); The sequence of the electromagnetic flux path is as follows: annular magnetic bridge (6) → working air gap 1 → N-pole L-shaped magnetic conductor → rotor disk (4) → working air gap 2 → stator core (2) → working air gap 2 → rotor disk (4) → S-pole L-shaped magnetic conductor → working air gap 1 → annular magnetic bridge (6).

3. The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to claim 1, characterized in that, The stator core (2) includes a stator back yoke (9) and axial stator teeth (10), and the stator slots (11) formed are straight slots. The armature winding (3) is wound on the axial stator teeth (10).

4. The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to claim 1, characterized in that, The rotor disk (4) is made of non-magnetic material; The L-shaped magnetic conductor (7) and the Halbach permanent magnet array (5) are both fixedly mounted on the rotor disk (4) so ​​that the rotor disk (4) rotates with the main shaft (1) when the main shaft (1) rotates, while the L-shaped magnetic conductor (7) and the Halbach permanent magnet array (5) rotate with the rotor disk (4).

5. The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to claim 1, characterized in that, In the Halbach permanent magnet array (5), each pair of poles is composed of several permanent magnets with different magnetization directions; The number of pole pairs in the Halbach permanent magnet array (5) is equal to the number of pole pairs in the motor.

6. The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to claim 1, characterized in that, The first type of magnetic conductor structure includes: the inner radius and outer radius of the cross section of the axial segment are the same as the inner ring radius and outer ring radius of the inner ring of the annular magnetic bridge (6); The second type of magnetic conductor structure includes: the inner radius and outer radius of the cross section of the axial segment are the same as the inner and outer ring radii of the outer ring of the annular magnetic bridge (6).

7. The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to claim 1, characterized in that, The annular magnetic bridge (6) is made of magnetic material. The structure of the annular magnetic bridge (6) includes a base plate and two annular sidewalls. The dimensions of the two annular sidewalls are constrained by the L-shaped magnetic conductor. In order to increase the cross-sectional area of ​​the electric excitation magnetic circuit, the inner and outer diameters of the two annular walls are the same as the inner and outer diameters of the axial section of the L-shaped magnetic conductor. The excitation winding (8) is embedded and fixed in the annular groove formed by the base plate and the two circular sidewalls. The excitation winding (8) adopts DC excitation.

8. The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to any one of claims 1-7, characterized in that, The rotor disk (4) is made of 3Cr13 stainless steel and is made into a thin disc shape.

9. The axial magnetic field hybrid excitation synchronous motor based on an L-shaped magnetic conductor according to any one of claims 1-7, characterized in that, The magnetic material is made of No. 10 steel or 1J22 iron-cobalt-vanadium soft magnetic alloy.

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