Switched reluctance motor

Abstract

The invention discloses a switched reluctance motor which comprises a stator, a winding coil and a rotor, the stator and the rotor are both of a salient pole structure, the rotor is coaxially nested on the inner side of the stator, and a three-dimensional air gap is formed between the stator and the rotor; the stator comprises a stator pole and a stator yoke, the stator pole comprises an excitation pole and an auxiliary pole, and the stator yoke is composed of a plurality of modules which are mutually connected through stator mortises and tenons; the rotor comprises rotor blocks and a non-magnetic-conductive rotor sleeve, the rotor blocks with the same size and shape are concentrically embedded into the surface of the non-magnetic-conductive rotor sleeve at equal intervals, and a rotor block gap is formed between every two adjacent rotor blocks. According to the switched reluctance motor, the length of a magnetic circuit can be effectively shortened, the overlapping area of stator and rotor poles at the aligned position is increased, the magnetic flux reversal phenomenon in the stator is eliminated, magnetic coupling among phases is reduced, the output torque density and efficiency of the switched reluctance motor are improved under the condition that the size of the motor is not changed, and meanwhile the reliability and fault tolerance of the motor are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a switched reluctance motor. Background Art

[0002] The switched reluctance motor is a single-excitation double-pole motor. Due to its simple structure, low cost, high reliability, strong fault tolerance and wide speed regulation range, it has broad application prospects in high-end equipment such as electric vehicles and aerospace. However, the torque density and efficiency of the switched reluctance motor are slightly lower than those of other types of motors, which limits its further application in high-end equipment.

[0003] In order to improve the output torque density and efficiency of the switched reluctance motor, domestic and foreign scholars have carried out a lot of research work around the switched reluctance motor itself. Among them, some scholars have comprehensively optimized the number of stator and rotor poles and size parameters of the motor based on the traditional switched reluctance motor structure, and some scholars have proposed new switched reluctance motor structures such as block stator type, block rotor type, and axial flux. Although these structures can effectively improve the performance of the switched reluctance motor, their performance advantages are not obvious compared with other types of motors. In order to enhance the competitiveness of the switched reluctance motor in the field of high-end equipment, new switched reluctance motor structures should be explored as soon as possible to further improve the output torque density and efficiency of the switched reluctance motor. Summary of the invention

[0004] The purpose of the present invention is to provide a switched reluctance motor, which can effectively shorten the length of the magnetic circuit, increase the overlapping area of ​​the stator and rotor poles in the aligned position, eliminate the flux reversal phenomenon in the stator, and reduce the magnetic coupling between the phases, thereby improving the output torque density and efficiency of the switched reluctance motor without changing the volume of the motor, solving the problems of low output torque density and low efficiency of traditional switched reluctance motors, and enhancing the reliability and fault tolerance of the motor.

[0005] To achieve the above object, the present invention provides a switched reluctance motor, comprising a stator, a winding coil and a rotor, wherein the stator and the rotor are both salient pole structures, the rotor is coaxially nested inside the stator, and a three-dimensional air gap is formed between the stator and the rotor;

[0006] The stator includes a stator pole and a stator yoke, the stator pole includes an excitation pole and an auxiliary pole, the excitation pole and the auxiliary pole are evenly arranged on the inner side of the stator yoke along the circumferential direction, the number of the excitation pole and the auxiliary pole is the same, and the stator yoke is composed of a plurality of modules and connected to each other through stator mortise and tenon joints;

[0007] The winding coil adopts a concentrated winding structure, the winding coil is only wound on the excitation pole, and the number of turns and winding direction of the winding coil on each excitation pole are the same;

[0008] The rotor comprises rotor blocks and a non-magnetic rotor sleeve, wherein the rotor blocks of the same size and shape are embedded concentrically and at equal intervals on the surface of the non-magnetic rotor sleeve, and rotor block gaps are formed between adjacent rotor blocks;

[0009] The number of the stator poles is 6m, and the number of the rotor blocks is 5m, wherein m is an integer not less than 1.

[0010] Preferably, the pole arc of the excitation pole is not less than twice the step angle and the sum of the pole arc of the rotor block gap, the pole arc of the auxiliary pole is not less than one time the step angle, the sum of the pole arcs of the excitation pole and the auxiliary pole is smaller than the angle between the two excitation pole axes, the pole arc of the rotor block is not less than twice the step angle and the sum of the pole arcs between the excitation pole and the auxiliary pole, but is smaller than one rotor pole pitch; wherein the rotor pole pitch is 360° divided by the number of rotor poles, and the step angle is the rotor pole pitch divided by the number of phases of the motor.

[0011] Preferably, the surfaces of the stator poles and the rotor blocks both adopt mutually matching concave-convex structures to form the three-dimensional air gap.

[0012] Preferably, the motor is a three-phase motor. When m=1, the winding coil on each of the excitation poles constitutes a phase alone; when m≥2, the winding coils on every two of the excitation poles are connected to constitute a phase, and the connection method of the three-phase windings must be exactly the same to ensure that the circuits and magnetic circuits of each phase of the motor are consistent.

[0013] Preferably, each phase winding adopts a pulse power supply mode.

[0014] Preferably, the stator and rotor blocks are made of electrical steel plates with good magnetic conductivity by stamping and stacking; the non-magnetic rotor sleeve is made of a lightweight material with certain strength but no magnetic conductivity; the gaps in the rotor blocks are filled with non-magnetic and non-conductive materials; the winding coil is made of copper wire with good conductivity, which is then dipped in paint and dried.

[0015] Therefore, the beneficial effects of the present invention using the above-mentioned switched reluctance motor are as follows:

[0016] (1) By adopting a hybrid stator pole, a segmented rotor and a three-dimensional air gap structure, the magnetic flux path of the motor is shortened, the overlapping area of ​​the stator and rotor poles in the aligned position is increased, the magnetic flux reversal phenomenon in the motor stator is eliminated, the magnetic coupling between the phases is reduced, and the magnetomotive force requirement is reduced, the air gap magnetic flux density is increased, the loss of the motor is reduced, and the electromagnetic isolation between the phases of the motor is enhanced, thereby improving the output torque density and efficiency of the switched reluctance motor without changing the volume of the motor, solving the problems of low output torque density and low efficiency of the traditional switched reluctance motor, and improving the reliability and fault tolerance of the motor. In addition, the three-dimensional air gap proposed by the present invention can be obtained by machining methods such as laser cutting or wire cutting, and the shape and size of the air gap can be selected without considering the thickness of the electrical silicon steel sheet, making the air gap design more flexible.

[0017] (2) By adopting concentrated winding and using mortise and tenon structure in the stator yoke to modularize the stator, the winding process and the assembly process between the stator and rotor are greatly simplified, solving the stator and rotor assembly problem caused by the three-dimensional air gap and reducing the production cost of the motor.

[0018] (3) By setting the rotor block gap and filling the rotor block gap with non-magnetic and non-conductive materials, the eddy current loss generated in the rotor during the operation of the motor is effectively suppressed, and the wind friction loss is reduced, thereby reducing the operating loss of the motor and improving the operating efficiency of the motor.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of a switched reluctance motor embodiment 1 of the present invention;

[0021] Figure 2 It is a cross-sectional structural schematic diagram of a switched reluctance motor embodiment 1 of the present invention;

[0022] Figure 3 It is a schematic diagram of a first air gap structure scheme of a switched reluctance motor of the present invention;

[0023] Figure 4 It is a schematic diagram of a second air gap structure scheme of a switched reluctance motor of the present invention;

[0024] Figure 5 Schematic diagram of a third air gap structure scheme of a switched reluctance motor of the present invention;

[0025] Figure 6 It is a winding connection diagram of a switched reluctance motor embodiment 1 of the present invention;

[0026] Figure 7It is a schematic diagram of the magnetic flux path after the A-phase winding of the switched reluctance motor embodiment 1 of the present invention is energized;

[0027] Figure 8 It is a schematic diagram of the magnetic flux path after the B-phase winding of the first embodiment of the switched reluctance motor of the present invention is energized;

[0028] Fig. 9 It is a schematic diagram of the magnetic flux path after the C-phase winding of the first embodiment of the switched reluctance motor of the present invention is energized;

[0029] Fig.10 It is a schematic diagram of the overall structure of a second embodiment of a switched reluctance motor of the present invention;

[0030] Fig.11 It is a winding connection diagram of a second embodiment of a switched reluctance motor of the present invention;

[0031] Fig.12 It is a schematic diagram of the magnetic flux path after the A-phase winding of the second embodiment of the switched reluctance motor of the present invention is energized.

[0032] Reference numerals

[0033] 1. Stator; 10. Excitation pole; 11. Auxiliary pole; 12. Stator yoke; 2. Winding coil; 3. Rotor; 30. Rotor block; 31. Non-magnetic rotor sleeve; 32. Rotor block gap; 4. Three-dimensional air gap; 5. Stator mortise and tenon. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0035] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] A switched reluctance motor of the present invention is a three-phase motor, the number of stator poles and the number of rotor blocks thereof are matched according to the relationship of 6m / 5m, the number of stator poles is 6m, the number of rotor blocks 30 is 5m, wherein m is an integer not less than 1. A switched reluctance motor of the present invention is described in detail below in conjunction with the accompanying drawings:

[0037] Embodiment 1

[0038] like Figure 1 and Figure 2 As shown, a switched reluctance motor provided by the present invention comprises a stator 1, a winding coil 2 and a rotor 3. The stator 1 and the rotor 3 are salient pole structures, the stator 1 is at the outermost side, the rotor 3 is at the inner side of the stator 1, the stator 1 and the rotor 3 are coaxially nested, and a three-dimensional air gap 4 is formed between the stator 1 and the rotor 3.

[0039] The stator 1 includes a stator pole and a stator yoke 12. The stator pole includes an excitation pole 10 and an auxiliary pole 11. The excitation pole 10 and the auxiliary pole 11 are evenly arranged on the inner side of the stator yoke 12 along the circumferential direction. The number of the excitation poles 10 and the auxiliary poles 11 is the same, which is half of the total number of the stator poles. The stator yoke 12 is provided with a stator tenon 5. The stator 1 is divided into a plurality of modules according to the stator tenon 5. The number of the modules is the same as the number of the stator tenon 5. The winding coil 2 adopts a concentrated winding structure. The winding coil 2 is only wound on the excitation pole 10. There is no winding coil of any form on the auxiliary pole 11, which only provides a return path for the magnetic flux generated by the winding coil 2. By adopting a concentrated winding and using a tenon structure in the stator yoke 12 to modularize the stator, the winding process of the winding coil 2 and the assembly process between the stator and the rotor are greatly simplified, and the assembly problem of the stator and the rotor caused by the three-dimensional air gap 4 is solved, while reducing the production cost of the motor.

[0040] The rotor 3 includes rotor blocks 30, a non-magnetic rotor sleeve 31 and a rotor block gap 32. The number of rotor blocks 30 matches the number of stator poles in a ratio of 5m / 6m. The rotor blocks 30 of the same size and shape are concentrically and evenly embedded in the surface of the non-magnetic rotor sleeve 31 through dovetail grooves at equal intervals. There is a rotor block gap 32 between adjacent rotor blocks 30. The rotor block gap 32 can be filled with non-magnetic and non-conductive materials. The rotor block gap 32 can effectively suppress the eddy current loss generated in the rotor 3 when the motor is running, and reduce the wind friction loss, thereby reducing the operating loss of the motor and improving the operating efficiency of the motor.

[0041] The stator 1 and the rotor block 30 in this embodiment are made of electrical thin steel plates with good magnetic conductivity, such as electrical pure iron, electrical silicon steel sheets B35A350, 50WW470, DR510, 35PN440 and M19, etc., which are stamped and stacked; the non-magnetic rotor sleeve 31 is made of a lightweight material with certain strength but no magnetic conductivity, such as aluminum, titanium alloy, etc.; the rotor block gap 32 is filled with a non-magnetic and non-conductive material, such as epoxy resin, etc.; the winding coil 2 is made of copper wire with good conductive properties, which is then dipped in paint and dried.

[0042] In addition, in order to enable the motor to output the largest possible torque, the pole arc of the excitation pole 10 is greater than or equal to the sum of twice the step angle and the pole arc of the rotor block gap 32, the pole arc of the auxiliary pole 11 is greater than or equal to one step angle, the sum of the pole arcs of the excitation pole 10 and the auxiliary pole 11 is less than the angle between the axes of the two excitation poles 10, and the pole arc of the rotor block 30 is greater than or equal to twice the step angle and the sum of the pole arcs between the excitation pole 10 and the auxiliary pole 11, but less than one rotor pole pitch. Among them, the rotor pole pitch is equal to 360° divided by the number of rotor poles, and the step angle is equal to the rotor pole pitch divided by the number of phases of the motor. In this embodiment, the value of m is equal to 1, the number of stator poles of the motor is 6, the number of rotor poles is 5, the rotor pole pitch of the motor is 72°, and the step angle is 24°.

[0043] like Figure 3 As shown, the surfaces of the stator pole and the rotor 3 both adopt a concave-convex structure. The embodiment adopts scheme 1, and the shape of the concave-convex structure is trapezoidal. The concave-convex structure on the surface of the stator pole matches the concave-convex structure on the surface of the rotor 3 to form a three-dimensional air gap 4.

[0044] In addition, other structural solutions can also be selected, such as Figure 4 As shown in the second scheme, the surfaces of the stator pole and the rotor 3 both adopt triangular concave-convex structures, and the concave-convex structure of the stator pole surface matches the concave-convex structure of the rotor 3 surface to form a three-dimensional air gap 4. Figure 5 As shown in scheme three, the surfaces of the stator pole and the rotor 3 both adopt a wavy concave-convex structure, and the concave-convex structure on the surface of the stator pole matches the concave-convex structure on the surface of the rotor 3 to form a three-dimensional air gap 4. Among them, the trapezoidal, triangular and wavy concave-convex structures can be obtained by machining methods such as laser cutting or wire cutting. When the motor adopts a three-dimensional air gap 4, without changing the outer diameter of the motor, the stack length, the air gap length and the stator and rotor pole arc coefficient, the motor can expand the overlapping area between the stator pole and the rotor pole in the rotor alignment position, which can effectively reduce the magnetic resistance of the air gap, increase the magnetic flux density of the air gap, and thereby effectively improve the output torque density and efficiency of the motor. As shown Figure 6 As shown, the winding coil 2 on each excitation pole 10 independently constitutes one phase, and the number of turns and winding direction of the winding coil 2 on each excitation pole 10 are the same.

[0045] like Figure 7 As shown, when the A-phase winding is energized, the magnetic flux starts from the excitation pole 10 where the A-phase winding is located, passes through the air gap, passes through the rotor block 30 and the auxiliary poles 11 on both sides of the excitation pole 10 where the A-phase winding is located to form a closed loop. According to the "minimum magnetic resistance principle", the magnetic flux will cause the motor to generate electromagnetic torque, pushing the rotor 3 to move to the A-phase alignment position, that is, the position where the axis of the excitation pole 10 where the A-phase winding is located is aligned with the axis of the rotor block gap 32.

[0046] Similarly, when the B phase winding is energized, a magnetic flux will be generated in the motor. Figure 8 As shown in FIG. 1 , its path is similar to the path of the magnetic flux generated by the A-phase winding. This magnetic flux enables the motor to generate electromagnetic torque and push the rotor 3 to move to a position aligned with the B-phase. When the C-phase winding is energized, a magnetic flux is generated in the motor. Fig. 9 As shown in the figure, its path is similar to the path of the magnetic flux generated by the A-phase winding. This magnetic flux enables the motor to generate electromagnetic torque and push the rotor 3 to move to the position aligned with the C-phase. Therefore, when the A, B, and C three-phase windings are alternately turned on and off, the motor can generate continuous magnetic resistance torque to drive the rotor to rotate. In addition, Figure 7 , Figure 8 and Fig. 9 It can be seen that the magnetic flux flow path of the switched reluctance motor of this embodiment is a short magnetic circuit, and when the motor changes phase, there is no reverse magnetic flux in the stator core. This structural feature can significantly improve the magnetic flux utilization of the motor, thereby increasing the output torque of the motor and reducing the operating loss of the motor, thereby improving the operating efficiency of the motor. In addition, the magnetic flux of each phase of the motor is basically uncoupled, which can effectively improve the reliability and fault tolerance of the motor.

[0047] Embodiment 2

[0048] like Fig.10 As shown, the difference between this embodiment and the first embodiment is that: in this embodiment, the value of m is equal to 2, the number of stator poles of the motor is 12, the number of rotor poles is 10, the rotor pole pitch of the motor is 36°, and the step angle is 12°.

[0049] like Fig.11 As shown, in this embodiment, the winding coils 2 on every two excitation poles 10 are connected to form one phase, such as: the A-phase winding is formed by connecting the windings on the Ps1 excitation pole and the Ps4 excitation pole, the B-phase winding is formed by connecting the windings on the Ps2 excitation pole and the Ps5 excitation pole, and the C-phase winding is formed by connecting the windings on the Ps3 excitation pole and the Ps6 excitation pole. At the same time, in order to ensure that the circuits and magnetic circuits of each phase of the motor are consistent, the connection method (series or parallel) of the three-phase windings A, B, and C is also exactly the same.

[0050] like Fig.12As shown, in this embodiment, the magnetic flux in the motor is radially symmetrical, and the motor does not generate unbalanced radial magnetic pull, which is beneficial to reducing the vibration and noise of the motor, thereby increasing the service life of the motor bearings and reducing the operation and maintenance costs of the motor.

[0051] In summary, a switched reluctance motor of the present invention is a three-phase motor, and the number of stator poles and the number of rotor blocks are matched according to the relationship of 6m / 5m, the number of stator poles is 6m, and the number of rotor blocks 30 is 5m, wherein m is an integer greater than or equal to 1. When m is equal to 1, the connection principle of the winding coil 2 is consistent with the connection principle of the winding coil 2 in the first embodiment; when m is greater than or equal to 2, the connection principle of the winding coil 2 is consistent with the connection principle of the winding coil 2 in the second embodiment, that is, the winding coils 2 on every two excitation poles 10 are connected to form one phase, and the connection method of the three-phase windings must be exactly the same to ensure that the circuits and magnetic circuits of each phase of the motor are consistent.

[0052] Therefore, the present invention adopts the above-mentioned switched reluctance motor, which can effectively shorten the length of the magnetic circuit, increase the overlapping area of ​​the stator and rotor poles in the aligned position, eliminate the flux reversal phenomenon in the stator, and reduce the magnetic coupling between the phases. Therefore, without changing the volume of the motor, the output torque density and efficiency of the switched reluctance motor are improved, and the problems of low output torque density and low efficiency of traditional switched reluctance motors are solved, while the reliability and fault tolerance of the motor are enhanced.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A switched reluctance motor, characterized in that: It includes a stator, a winding coil and a rotor, wherein the stator and the rotor are both salient pole structures, the rotor is coaxially nested inside the stator, and a three-dimensional air gap is formed between the stator and the rotor; The stator includes a stator pole and a stator yoke, the stator pole includes an excitation pole and an auxiliary pole, the excitation pole and the auxiliary pole are evenly arranged on the inner side of the stator yoke along the circumferential direction, the number of the excitation pole and the auxiliary pole is the same, and the stator yoke is composed of a plurality of modules and connected to each other through stator mortise and tenon joints; The winding coil adopts a concentrated winding structure, the winding coil is only wound on the excitation pole, and the number of turns and winding direction of the winding coil on each excitation pole are the same; The rotor comprises rotor blocks and a non-magnetic rotor sleeve, wherein the rotor blocks of the same size and shape are embedded concentrically and at equal intervals on the surface of the non-magnetic rotor sleeve, and rotor block gaps are formed between adjacent rotor blocks; The number of the stator poles is 6m, and the number of the rotor blocks is 5m, wherein m is an integer not less than 1.

2. A switched reluctance motor according to claim 1, characterized in that: The pole arc of the excitation pole is not less than twice the step angle and the sum of the pole arc of the rotor block gap, the pole arc of the auxiliary pole is not less than one time the step angle, the sum of the pole arcs of the excitation pole and the auxiliary pole is smaller than the angle between the two excitation pole axes, the pole arc of the rotor block is not less than twice the step angle and the sum of the pole arcs between the excitation pole and the auxiliary pole, but is smaller than one rotor pole pitch; wherein the rotor pole pitch is 360° divided by the number of the rotor poles, and the step angle is the rotor pole pitch divided by the number of phases of the motor.

3. The switched reluctance motor according to claim 1, characterized in that: The surfaces of the stator poles and the rotor blocks both adopt concave-convex structures that match each other to form the three-dimensional air gap.

4. The switched reluctance motor according to claim 1, characterized in that: The motor is a three-phase motor. When m=1, the winding coil on each of the excitation poles constitutes a phase alone; when m≥2, the winding coils on every two of the excitation poles are connected to constitute a phase, and the connection method of the three-phase windings must be exactly the same to ensure that the circuits and magnetic circuits of each phase of the motor are consistent.

5. The switched reluctance motor according to claim 1, characterized in that: Each phase winding adopts pulse power supply.

6. The switched reluctance motor according to claim 1, characterized in that: The stator and rotor blocks are made of electrical steel plates with good magnetic conductivity by stamping and stacking; the non-magnetic rotor sleeve is made of material without magnetic conductivity; the gap between the rotor blocks is filled with non-magnetic and non-conductive materials; the winding coil is made of copper wire with good conductivity, which is then dipped in paint and dried.

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