Novel composite magnetic circuit permanent magnet auxiliary switch reluctance motor

Abstract

The invention provides a novel composite magnetic circuit permanent magnet auxiliary switch reluctance motor, which comprises a stator, a winding, block rotors, permanent magnets, a non-magnetic support piece and a rotating shaft, and is characterized in that the non-magnetic support piece is coaxially sleeved in the stator, the block rotors are uniformly arranged on the non-magnetic support piece along the circumferential direction, the rotating shaft is arranged in the middle, and the non-magnetic support piece is sleeved outside the rotating shaft; slotted holes with the number equal to that of the block rotors are uniformly machined in the non-magnetic supporting piece in the circumferential direction, the slotted holes are used for installing the block rotors, the multiple block rotors are uniformly arranged on the outer wall of the non-magnetic supporting piece in the circumferential direction, the permanent magnets are arranged at the tooth ends of the stator, and radial air gaps are reserved between the stator and the block rotors. According to the scheme, the magnetic flux path is greatly shortened, and the characteristics of high power density and low iron loss are effectively considered.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of electric machines, and particularly relates to a novel composite magnetic circuit permanent magnet auxiliary switched reluctance motor. BACKGROUND

[0002] Switched reluctance motor gradually becomes a research hotspot in rare earth-free motors due to its simple structure, flexible control, high efficiency, low cost, strong fault tolerance and other advantages. The salient pole structure of the ordinary switched reluctance motor has low power density and insufficient torque capacity. The topology innovation of the traditional switched reluctance motor focuses on two major technical directions of block design and hybrid excitation. Block design helps to shorten the magnetic flux path, reduce iron loss, and improve reliability and fault tolerance by using electromagnetic isolation effect. Hybrid excitation technology opens up a new path for improving torque performance through permanent magnet auxiliary excitation.

[0003] The motor structure disclosed in the document with publication number CN111740515A and the name of "a hybrid excitation switched reluctance motor with modular rotor" adopts a hybrid excitation structure, the rotor is modularized, permanent magnets are arranged between the stator teeth, windings and permanent magnet double magnetic circuits are arranged to improve the power density of the motor.

[0004] The existing hybrid excitation structure is a double magnetic circuit structure, that is, the magnetic circuit generated by the excitation of the stator winding and the magnetic circuit generated by the excitation of the permanent magnet used by the stator. The torque ripple of the motor is enhanced by superimposing the two magnetic circuits, and there is a lack of more magnetic circuit structure topology configurations. SUMMARY

[0005] The purpose of the application is to solve the problems of low torque density and excessive local magnetic density between teeth of the existing switched reluctance motor. On the basis of the double magnetic circuit, a three-magnetic circuit magnetic flux coordination configuration of the motor during single-phase excitation is further expanded, which significantly improves the air gap magnetic density and torque output capacity. At the same time, by forming a bifurcated structure of the stator teeth, the maximum / minimum inductance ratio of the motor is improved while the inter-tooth magnetic density is reduced. Through reasonable structure topology layout, in addition to the winding excitation circuit, there is a permanent magnet circuit corresponding to the phase stator, and another new excitation circuit is formed by using the permanent magnets on the adjacent phases.

[0006] The technical scheme of the application includes:

[0007] A novel composite magnetic circuit permanent magnet auxiliary switched reluctance motor, comprising: a stator, a winding, a split rotor, a permanent magnet, a non-magnetic support and a rotating shaft, wherein the stator is coaxially sleeved with the non-magnetic support, the split rotor is uniformly arranged on the non-magnetic support in the circumferential direction, the rotating shaft is in the middle, the rotating shaft is sleeved with the non-magnetic support, a plurality of slot holes equal to the number of split rotors are uniformly processed on the non-magnetic support in the circumferential direction, the slot holes are used for mounting the split rotors, a plurality of split rotors are uniformly arranged on the outer wall of the non-magnetic support in the circumferential direction, the permanent magnet is arranged at the tooth end of the stator, and a radial air gap is left between the stator and the split rotor.

[0008] Beneficial effects:

[0009] A novel five-phase 20 / 14 stator / rotor pole configuration switched reluctance motor is proposed, and the stator is divided into a stator wide tooth with winding and a stator narrow tooth without winding. The stator wide tooth is responsible for generating the main magnetic circuit, the split rotor and the stator narrow tooth cooperatively guide the magnetic flux, forming a short magnetic circuit system of the stator and rotor linkage, greatly shortening the magnetic flux path, and effectively balancing the high power density and low iron loss characteristics;

[0010] The permanent magnet array is embedded between the stator wide tooth and the stator narrow tooth, a vector superposition composite magnetic circuit system of the winding excitation magnetic field and the permanent magnet bias magnetic field is constructed, a three-path magnetic flux cooperative configuration with dynamic compensation characteristics is formed, and the air gap magnetic density and torque output capacity are significantly improved;

[0011] The bifurcated structure is arranged at the tooth end of the stator wide tooth, the maximum / minimum inductance ratio is improved, and the tooth saturation magnetic density is reduced;

[0012] The stator narrow tooth without winding in the application can not only be used as a magnetic circuit to realize a shorter magnetic circuit, but also can play an isolation role, effectively realizing the isolation among the magnetic circuit, the electric circuit and the temperature. When a fault occurs in a phase of the motor, the stator narrow tooth can reduce the mutual inductance of the motor by providing a magnetic circuit, reduce the influence on other phase windings, and improve the ability of the motor to operate with faults. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a radial sectional view of a novel composite magnetic circuit permanent magnet auxiliary switched reluctance motor;

[0014] Figure 2 is Figure 1 a single stator structure schematic diagram in

[0015] Figure 3 is a schematic diagram of an excitation circuit when the winding of the motor is excited without considering the permanent magnet;

[0016] Figure 4 is a schematic diagram of an excitation circuit when only the permanent magnet is considered without winding excitation;

[0017] Figure 5 is a schematic diagram of an excitation circuit when the motor is excited according to the present application.

[0018] Reference signs: 1, stator; 1-1, wide stator tooth; 1-2, narrow stator tooth; 1-3, stator yoke; 2, winding; 3, block rotor; 4, permanent magnet; 5, non-magnetic support; 6, rotating shaft. DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present disclosure will be described in greater detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood, and so that the scope of the present disclosure can be completely conveyed to those skilled in the art.

[0020] Figure 1 is a schematic diagram of a radial section of a novel composite magnetic circuit permanent magnet auxiliary switched reluctance motor according to the present application, Figure 2 is Figure 1 a schematic diagram of a single stator structure. Referring to Figure 1 and Figure 2 , the present application takes a five-phase 20 / 14 stator and rotor pole number motor as an example, including a stator 1, a winding 2, a block rotor 3, a permanent magnet 4, a non-magnetic support 5, and a rotating shaft 6. The stator 1 has a non-magnetic support 5 coaxially sleeved inside, and the non-magnetic support 5 has a plurality of block rotors 3 evenly arranged in the circumferential direction. The rotating shaft 6 is in the middle, and the non-magnetic support 5 is sleeved outside the rotating shaft 6. The non-magnetic support 5 has a plurality of slot holes equal in number to the block rotors 3 and evenly machined in the circumferential direction, and the slot holes are used to install the block rotors 3. A plurality of block rotors 3 are evenly arranged in the circumferential direction on the outer wall of the non-magnetic support 5. The permanent magnet 4 is arranged at the tooth end of the stator 1. A radial air gap is left between the stator 1 and the block rotor 3.

[0021] The stator is composed of a stator yoke and stator teeth, and the stator teeth are composed of a plurality of wide stator teeth and narrow stator teeth that are equal in number and arranged alternately. Specifically, as shown in Figure 2 , the stator 1 can be further divided into wide stator teeth 1-1, narrow stator teeth 1-2, and a stator yoke 1-3, and the wide stator teeth 1-1 and the narrow stator teeth 1-2 are alternately and evenly distributed in the circumferential direction. In the case of a five-phase 20 / 14 stator and rotor pole number motor, there are 10 wide stator teeth 1-1, 10 narrow stator teeth 1-2, and 14 block rotors 3.

[0022] The tooth end of the stator wide tooth 1-1 can be bifurcated into two tooth poles, and is arranged in a bifurcated structure. Specifically, a trapezoidal groove is formed in the middle of the inner end surface of each stator wide tooth 1-1, and the groove divides each stator wide tooth 1-1 into two identical bifurcated teeth, which correspond to two adjacent block rotors 3. The two ends refer to the ends of the two tooth poles after the bifurcation of the stator wide tooth 1-1 (i.e. the ends of the bifurcated teeth), which correspond to two adjacent block rotors 3. The bifurcated shape realizes the maximization of motor torque and reduces the problem of magnetic density oversaturation at the tooth end by optimizing the maximum / minimum inductance ratio of the motor.

[0023] The tooth width of the stator wide tooth 1-1 is about twice the tooth width of the stator narrow tooth 1-2. The height of the stator yoke 1-3 is approximately equal to the tooth width of the stator wide tooth 1-1. The stator wide tooth 1-1 is wound with a winding 2, and the stator narrow tooth 1-2 is not wound with a winding. Specifically, the stator wide tooth 1-1 is wound with a concentrated winding 2 at both ends, and the winding direction on each stator wide tooth 1-1 is the same, according to the right-hand screw rule, Figure 2 Each stator wide tooth 1-1 in the example is N-pole. The two opposite stator wide teeth 1-1 constitute a phase winding. The stator narrow tooth 1-2 is not wound with a winding, and only serves to provide an excitation circuit.

[0024] Rectangular block-shaped permanent magnets are arranged between the stator wide tooth 1-1 and the stator narrow tooth 1-2 at the tooth end. When N-pole windings are uniformly arranged on the stator wide tooth 1-1, the magnetization direction of the permanent magnets is that the stator narrow tooth 1-2 points to the stator wide tooth 1-1, as shown by the black arrow in Figure 1 When S-pole windings are uniformly arranged on the stator wide tooth 1-1, the magnetization direction of the permanent magnets is opposite. The two permanent magnets at the two ends of the tooth end of each stator wide tooth 1-1 constitute a pair, Figure 1 Ten pairs of a total of 20 permanent magnet blocks are uniformly arranged in

[0025] The radial outer end of the block rotor 3 is a fan-shaped structure, and the radial inner end is a rectangular structure. The arc surface of the fan-shaped block and the entire air gap arc surface form a complete circular arc surface. The rectangular structure (rectangular block) is used to embed the block rotor 3 in the non-magnetic support 5. The non-magnetic support 5 is internally processed with a rectangular slot hole (or key groove) matching the shape of the radial inner end of the block rotor 3. The rectangular end of the block rotor 3 is inserted into the slot hole for fixation. The slot hole of the non-magnetic support 5 serves as a positioning and mechanical fixation, ensuring uniform distribution of the rotor modules. The block rotor 3 and the non-magnetic support 5 are fixed by interference fit or adhesion, ensuring mechanical stability.

[0026] In this embodiment, the position where the center line of the segmented rotor 3 is aligned with the center line of the stator wide tooth 1-1 is defined as the misaligned position of the motor, at which the inductance of the motor is the smallest, i.e. the minimum inductance position. The position where the center line of the segmented rotor 3 is aligned with the center line of the stator slot is defined as the aligned position of the motor, at which the inductance of the motor is the largest, i.e. the maximum inductance position. When analyzing the excitation circuit, the maximum inductance position is always taken as an example.

[0027] Referring to Figure 3 When the winding on a single stator wide tooth 1-1 is excited without considering the permanent magnet 4, i.e. the winding current I>0 on a single stator wide tooth 1-1 and the current I=0 of the remaining windings. The magnetic circuit generated by the winding can be divided into two circuits at the end part of the stator wide tooth, and the two excitation circuits are symmetrically distributed. The excitation circuit path is: stator wide tooth 1-1, air gap, segmented rotor 3, air gap, stator narrow tooth 1-2, stator yoke 1-3, stator wide tooth 1-1, forming a closed loop.

[0028] Referring to Figure 4 When the permanent magnet 4 is excited alone and the winding is not energized, i.e. all winding currents I=0. At this time, the excitation circuit generated by the permanent magnet 4 only passes through the inside of the stator 1 and does not pass through the air gap, so it does not generate cogging torque. The excitation circuit path is: permanent magnet 4, stator wide tooth 1-1, stator yoke 1-3, stator narrow tooth 1-2, permanent magnet 4, forming a closed loop. Comparing Figure 3 and Figure 4 , the magnetic circuit generated by the winding alone is opposite to the magnetic circuit when the permanent magnet alone, as shown by the arrows in the excitation circuit in the figure.

[0029] Referring to Figure 5 When a single stator tooth winding and all permanent magnets 4 act at the same time, three magnetic circuits can be formed on the rotor side of the corresponding air gap. Through the matching design of the winding polarity and the magnetization direction of the permanent magnet, the winding magnetic field, the current excitation phase stator tooth two side permanent magnet magnetic field and the adjacent two phase permanent magnet in one side direction form three path superposition. The document with publication number CN111740515A and the name of "a self-modular hybrid excitation switched reluctance motor" only has two path superpositions, and the present application utilizes the effect of adjacent phase permanent magnets to further improve the air gap flux density.

[0030] In summary, when the winding is not excited, the magnetic circuit of the permanent magnet only passes through the inside of the stator and does not pass through the air gap, so it does not generate cogging torque. When the winding is excited, in addition to the excitation circuit formed by the winding, the permanent magnets adjacent to the current excitation phase will generate an excitation circuit at the air gap, and the permanent magnets of the adjacent phase will also generate another excitation circuit, so three excitation circuits can be generated at the air gap at the same time.

[0031] While the application has been described in terms of several implementations, those skilled in the art will recognize that the application can be practiced with modifications within the spirit and scope of the application, which are encompassed by the description. Furthermore, it is to be understood that the application can be practiced with other specific forms without departing from the spirit or essential characteristics of the application. The foregoing description is considered as illustrative only of the principles of the application. Further, this description should not be regarded as limiting in any respect.

Claims

1. A novel compound magnetic circuit permanent magnet assisted switched reluctance motor characterized by, It comprises a stator (1), a winding (2), a segmented rotor (3), a permanent magnet (4), a non-magnetic support (5) and a rotating shaft (6), wherein the stator (1) is coaxially sleeved with the non-magnetic support (5), the non-magnetic support (5) is uniformly arranged with the segmented rotor (3) in the circumferential direction, the rotating shaft (6) is in the middle, the rotating shaft (6) is sleeved with the non-magnetic support (5), the non-magnetic support (5) is uniformly processed with a number of slot holes equal to that of the segmented rotor (3) in the circumferential direction, the slot holes are used for mounting the segmented rotor (3), the outer wall of the non-magnetic support (5) is uniformly arranged with a plurality of segmented rotors (3) in the circumferential direction, the permanent magnet (4) is arranged at the tooth end of the stator (1), and a radial air gap is left between the stator (1) and the segmented rotor (3). The stator (1) is divided into a stator wide tooth (1-1), a stator narrow tooth (1-2) and a stator yoke (1-3), and the stator wide tooth (1-1) and the stator narrow tooth (1-2) are alternately and uniformly distributed along the circumference.

2. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 1, wherein, In the case that the motor is a five-phase 20 / 14 stator and rotor pole number motor, it comprises 10 stator wide teeth (1-1), 10 stator narrow teeth (1-2) and 14 segmented rotors (3).

3. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 2, wherein, The tooth end of the stator wide tooth (1-1) is bifurcated into two tooth poles and is arranged in a bifurcated structure.

4. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 2, wherein, A trapezoidal groove is formed in the middle of the inner end face of each stator wide tooth (1-1), and the groove divides each stator wide tooth (1-1) into two identical bifurcated teeth corresponding to the segmented rotors (3) at both ends.

5. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 4, wherein, The tooth body width of the stator wide tooth (1-1) is twice that of the stator narrow tooth (1-2), the height of the stator yoke (1-3) is equal to the tooth body width of the stator wide tooth (1-1), the stator wide tooth (1-1) is wound with the winding (2), and the stator narrow tooth (1-2) is not wound with the winding.

6. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 4, wherein, Rectangular block permanent magnets (4) are arranged between the stator wide tooth (1-1) and the stator narrow tooth (1-2) at the tooth end, when N-pole windings are arranged on the stator wide tooth (1-1), the magnetization direction of the permanent magnet (4) is that the stator narrow tooth (1-2) points to the stator wide tooth (1-1), and when S-pole windings are arranged on the stator wide tooth (1-1), the magnetization direction of the permanent magnet (4) is opposite.

7. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 4, wherein, The radial outer end of the segmented rotor (3) is a fan-shaped structure, the radial inner end is a rectangular structure, and the arc surface of the fan-shaped block and the entire air gap arc surface form a complete circular arc surface.

8. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 4, wherein, The non-magnetic support (5) is internally processed with a rectangular slot hole matched with the shape of the radial inner end of the segmented rotor (3), and the rectangular end of the rotor (3) is inserted into the slot hole for fixation.

9. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 8, wherein, The segmented rotor (3) and the non-magnetic support (5) are fixed by interference fit or adhesion.

10. The novel composite magnetic circuit permanent magnet assisted switched reluctance motor of claim 9, wherein, ​

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