A switched reluctance motor

Abstract

The application discloses a switched reluctance motor, comprising a stator, winding coil and rotor, the stator and rotor are both salient pole structure, the rotor is coaxially nested in the inside of the stator, and three-dimensional air gap is formed between the stator and rotor; the stator comprises stator pole and stator yoke, the stator pole comprises excitation pole and auxiliary pole, the stator yoke is composed of several modules and is connected with each other through stator mortise and tenon; the rotor comprises rotor block and non-permeable rotor sleeve, the rotor block with same size and shape is embedded into the surface of the non-permeable rotor sleeve in concentric and equal interval, and rotor block gap is formed between adjacent rotor blocks. The application can effectively shorten the magnetic circuit length, increase the overlapping area of stator and rotor poles in alignment position, eliminate the magnetic flux reverse phenomenon in the stator, reduce the magnetic coupling between each phase, improve the output torque density and efficiency of the switched reluctance motor under the condition of not changing the motor volume, and enhance the reliability and fault tolerance of the motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to a switched reluctance motor. BACKGROUND

[0002] The switched reluctance motor is a single-excitation doubly salient motor, which has broad application prospects in electric vehicles, aerospace and other high-end equipment fields due to its simple structure, low cost, high reliability, strong fault tolerance and wide speed regulation range. 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 large amount of research work around the switched reluctance motor itself. Among them, some scholars based on the structure of the traditional switched reluctance motor, comprehensively optimize the pole number and size parameters of the stator and rotor of the motor, and some scholars propose new structures of the switched reluctance motor such as block stator type, block rotor type and axial flux type. Although these structures can effectively improve the performance of the switched reluctance motor, the performance advantage is not obvious compared with other types of motors. In order to enhance the competitiveness of the switched reluctance motor in the high-end equipment field, 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

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

[0005] In order to achieve the above purpose, the present application provides a switched reluctance motor, which comprises a stator, a winding coil and a rotor, the stator and the rotor are both salient pole structures, the rotor is coaxially nested on the inside of the stator, and a three-dimensional air gap is formed between the stator and the rotor.

[0006] The stator comprises a stator pole and a stator yoke, the stator pole comprises an excitation pole and an auxiliary pole, the excitation pole and the auxiliary pole are uniformly and alternately arranged on the inside of the stator yoke along the circumferential direction, the number of the excitation poles and the auxiliary poles is the same, and the stator yoke is composed of a plurality of modules and is connected to each other through stator mortise and tenon.

[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 the 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, the rotor blocks of the same size and shape are embedded on the surface of the non-magnetic rotor sleeve in a concentric and equidistant manner, and rotor block gaps exist 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 arcs of the rotor block gaps, the pole arc of the auxiliary pole is not less than the step angle, the sum of the pole arcs of the excitation pole and the auxiliary pole is less than the included angle between two excitation pole axes, and the pole arc of the rotor block is not less than twice the sum of the step angle and the pole arc between the excitation pole and the auxiliary pole, but is less than a 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.

[0011] Preferably, the surfaces of the stator poles and the rotor blocks are provided with 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 coils on each excitation pole form a phase, and when m ≥ 2, the winding coils on every two excitation poles are connected to form a phase, and the connection modes of the three-phase windings need to be completely the same to ensure that the motor circuits and magnetic circuits are consistent.

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

[0014] Preferably, the stator and the rotor blocks are punched and laminated from an electrical steel plate with good magnetic conductivity, the non-magnetic rotor sleeve is made of a material with certain strength but without magnetic conductivity and light weight, the rotor block gaps are filled with a material without magnetic conductivity and electrical conductivity, and the winding coils are made of copper wires with good electrical conductivity, which are wound, dipped in paint and dried.

[0015] Therefore, the application has the beneficial effects of the above-mentioned switch reluctance motor.

[0016] (1) By adopting mixed stator pole, block rotor and 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, thereby reducing the magnetic motive force requirement, increasing the air gap flux density, reducing the motor loss, and enhancing the electromagnetic isolation between the phases of the motor, 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 of the present application can be obtained by laser cutting or wire cutting machining, and the shape and size of the air gap do not need to consider the thickness of the electrical steel sheet, so that the air gap design is more flexible.

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

[0018] (3) By setting the rotor block gap and filling the non-magnetic and non-conductive material in the rotor block gap, 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 solutions of the present application will be further described in detail below by means of the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a whole structure schematic diagram of a switched reluctance motor embodiment one of the present application;

[0021] Figure 2 is a cross-sectional structure schematic diagram of a switched reluctance motor embodiment one of the present application;

[0022] Figure 3 is a schematic diagram of an air gap structure scheme one of a switched reluctance motor of the present application;

[0023] Figure 4 is a schematic diagram of an air gap structure scheme two of a switched reluctance motor of the present application;

[0024] Figure 5 is a schematic diagram of an air gap structure scheme three of a switched reluctance motor of the present application;

[0025] Figure 6 is a winding connection schematic diagram of a switched reluctance motor embodiment one of the present application;

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

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

[0028] Figure 9 is a schematic diagram of a magnetic flux path after the C-phase winding of the embodiment one of the switched reluctance motor of the present application is energized;

[0029] Figure 10 is a schematic diagram of the overall structure of the embodiment two of the switched reluctance motor of the present application;

[0030] Figure 11 is a schematic diagram of the winding connection of the embodiment two of the switched reluctance motor of the present application;

[0031] Figure 12 is a schematic diagram of a magnetic flux path after the A-phase winding of the embodiment two of the switched reluctance motor of the present application is energized.

[0032] Reference numerals

[0033] 1, stator; 10, field 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 solutions of the present application are further described below by means of the accompanying drawings and embodiments.

[0035] Unless otherwise defined, technical terms or scientific terms used in the present application shall be understood as having the usual meaning as understood by a person having ordinary skill in the art to which the present application pertains. The terms "first", "second", and similar terms used in the present application do not indicate any order, number, or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects listed before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are only used to indicate relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0036] The switch reluctance motor of the application is a three-phase motor, 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 not less than 1. The switch reluctance motor of the application will be described in detail below in combination with the drawings:

[0037] Embodiment one

[0038] As shown in Figure 1 and Figure 2 , the switch reluctance motor of the application 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 comprises stator poles and a stator yoke 12, the stator poles comprise excitation poles 10 and auxiliary poles 11, wherein the excitation poles 10 and the auxiliary poles 11 are uniformly and alternately arranged at 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, and each is half of the total number of stator poles, the stator yoke 12 is provided with stator mortise and tenon joints 5, the stator 1 is divided into a plurality of modules according to the stator mortise and tenon joints 5, and the number of the modules is the same as the number of the stator mortise and tenon joints 5. The winding coil 2 adopts a concentrated winding structure, the winding coil 2 is only wound on the excitation poles 10, and there is no winding coil of any form on the auxiliary poles 11, which only provides a return path for the magnetic flux generated by the winding coil 2. By adopting the concentrated winding and the mortise and tenon joint 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, the assembly problem of the stator and the rotor caused by the three-dimensional air gap 4 is solved, and the production cost of the motor is reduced.

[0040] The rotor 3 comprises rotor blocks 30, a non-magnetic rotor sleeve 31 and rotor block gaps 32, the number of the rotor blocks 30 is matched with the number of the stator poles according to the relationship of 5m / 6m, the rotor blocks 30 which are the same in size and shape are concentrically and equidistantly embedded into the surface of the non-magnetic rotor sleeve 31 through dovetail grooves, the rotor block gaps 32 are formed between adjacent rotor blocks 30, the rotor block gaps 32 can be filled with non-magnetic and non-conductive materials, the rotor block gaps 32 can effectively suppress the eddy current loss generated in the rotor 3 during the operation of the motor, reduce the wind friction loss, and further reduce the operating loss of the motor and improve the operating efficiency of the motor.

[0041] The stator 1 and the rotor block 30 in the embodiment are punched and laminated from an electric sheet steel with good magnetic conductivity, such as electric pure iron, electric silicon steel sheet B35A350, 50WW470, DR510, 35PN440 and M19, etc. The non-magnetic rotor sleeve 31 is made of a material with certain strength but without magnetic conductivity and light weight, such as aluminum, titanium alloy, etc. The rotor block gap 32 is filled with a material without magnetic and electric conductivity, such as epoxy resin, etc. The winding coil 2 is made of copper wire with good electric conductivity, which is wound, dipped in paint and dried.

[0042] In addition, in order to make the motor output the largest torque, the pole arc of the excitation pole 10 is greater than or equal to twice the sum of 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 the step angle, the sum of the pole arcs of the excitation pole 10 and the auxiliary pole 11 is less than the included angle between the axes of two excitation poles 10, and the pole arc of the rotor block 30 is greater than or equal to twice the sum of the step angle and the pole arc between the excitation pole 10 and the auxiliary pole 11, but less than a rotor pole pitch. 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 the 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] As shown in Figure 3 , the surfaces of the stator poles and the rotor 3 are provided with concave-convex structures. In the embodiment, the concave-convex structures are trapezoidal, and the concave-convex structures on the surfaces of the stator poles match the concave-convex structures on the surfaces of the rotor 3 to form the three-dimensional air gap 4.

[0044] In addition, other structure schemes can also be selected, such as Figure 4 , in which the surfaces of the stator poles and the rotor 3 are provided with triangular concave-convex structures, the concave-convex structures on the surfaces of the stator poles match the concave-convex structures on the surfaces of the rotor 3 to form the three-dimensional air gap 4. As shown in Figure 5 , the surfaces of the stator poles and the rotor 3 are provided with wave-shaped concave-convex structures, the concave-convex structures on the surfaces of the stator poles match the concave-convex structures on the surfaces of the rotor 3 to form the three-dimensional air gap 4. The trapezoidal, triangular and wave-shaped concave-convex structures can be obtained by machining methods such as laser cutting or wire cutting. When the motor is provided with the three-dimensional air gap 4, the overlapping area between the stator poles and the rotor poles at the aligned position of the rotor can be enlarged without changing the outer diameter, the stack length, the air gap length and the stator-rotor pole arc coefficient of the motor, which can effectively reduce the magnetic resistance of the air gap, increase the magnetic flux density of the air gap, and further effectively improve the output torque density and the efficiency of the motor. Figure 6 As shown in

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

[0046] Similarly, when phase B winding is energized, magnetic flux will be generated in the motor, such as... Figure 8 As shown, its path is similar to that of the magnetic flux generated by the A-phase winding. This magnetic flux causes the motor to produce electromagnetic torque, pushing rotor 3 to move to a position aligned with B. When the C-phase winding is energized, magnetic flux is generated in the motor as follows: Figure 9 As shown, its path is similar to that of the magnetic flux generated by phase A winding. This magnetic flux causes the motor to produce electromagnetic torque, driving rotor 3 to move to a position aligned with phase C. Therefore, when the three-phase windings A, B, and C are alternately switched on and off, the motor can generate continuous reluctance torque, driving the rotor to rotate. Furthermore, due to... Figure 7 , Figure 8 and Figure 9 As can be seen, the magnetic flux flow path of the switched reluctance motor in this embodiment is a short magnetic circuit, and there is no reverse magnetic flux in the stator core when the motor commutates. This structural feature can significantly improve the magnetic flux utilization rate of the motor, thereby increasing the output torque of the motor and reducing the operating losses of the motor, thus 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] Example 2

[0048] like Figure 10 As shown, the difference between this embodiment and Embodiment 1 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 Figure 11 As shown, in this embodiment, the winding coils 2 on every two excitation poles 10 are connected to form one phase. For example, phase A winding is formed by connecting the windings on excitation poles Ps1 and Ps4, phase B winding is formed by connecting the windings on excitation poles Ps2 and Ps5, and phase C winding is formed by connecting the windings on excitation poles Ps3 and Ps6. Meanwhile, to ensure consistency in the circuit and magnetic circuit of each phase of the motor, the connection methods (series or parallel) of the three-phase windings A, B, and C are also completely identical.

[0050] like Figure 12As shown, in the embodiment, the magnetic flux in the motor is radially symmetrical, the motor does not generate unbalanced radial magnetic pull, which is beneficial to reduce the vibration and noise of the motor, thereby improving the service life of the motor bearing and reducing the operation and maintenance cost of the motor.

[0051] In summary, the switch reluctance motor is a three-phase motor, 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, 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, every two winding coils 2 on the excitation pole 10 are connected to form a phase, and the connection mode of the three-phase winding needs to be completely the same to ensure that the motor circuits and magnetic circuits are consistent.

[0052] Therefore, by using the above switch reluctance motor, the magnetic path length can be effectively shortened, the overlapping area of the stator and rotor poles at the aligned position can be increased, the magnetic flux reversal phenomenon in the stator can be eliminated, the magnetic coupling between the phases can be reduced, and the output torque density and efficiency of the switch reluctance motor can be improved without changing the volume of the motor, thereby solving the problems of low output torque density and low efficiency of the traditional switch reluctance motor, and enhancing the reliability and fault tolerance of the motor.

[0053] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A switched reluctance motor characterised in that: The motor comprises a stator, winding coils and a rotor, the stator and the rotor are salient pole structures, 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 stator poles and a stator yoke, the stator poles comprise excitation poles and auxiliary poles, the excitation poles and the auxiliary poles are uniformly and alternately arranged on the inner side of the stator yoke along the circumferential direction, the number of the excitation poles is the same as that of the auxiliary poles, the stator yoke is composed of a plurality of modules and is connected to each other through stator mortise and tenon; The winding coils adopt a concentrated winding structure, the winding coils are wound on the excitation poles only, and the number of turns and the winding direction of the winding coils on each excitation pole are the same; The rotor comprises rotor blocks and a non-magnetic rotor sleeve, the rotor blocks which are the same in size and shape are concentrically and equidistantly embedded 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; The surfaces of the stator poles and the rotor blocks adopt matching concave-convex structures to form the three-dimensional air gap; The stator and the rotor blocks are stamped and laminated from an electrical steel plate with good magnetic conductivity, the non-magnetic rotor sleeve is made of a material without magnetic conductivity, the rotor block gaps are filled with a material without magnetic conductivity and electrical conductivity, and the winding coils are made of copper wires with good electrical conductivity, which are wound, dipped in paint and dried.

2. A switched reluctance machine according to claim 1, characterised in that: The pole arc of the excitation poles is not less than twice the step angle and the sum of the pole arcs of the rotor block gaps, the pole arc of the auxiliary poles is not less than the step angle, the sum of the pole arcs of the excitation poles and the auxiliary poles is less than the included angle between the axes of two excitation poles, and the pole arc of the rotor blocks is not less than twice the step angle and the sum of the pole arcs between the excitation poles and the auxiliary poles, but is less than a 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.

3. A switched reluctance machine according to claim 1, characterised in that: The motor is a three-phase motor, when m = 1, the winding coils on each excitation pole separately form a phase, and when m ≥ 2, the winding coils on every two excitation poles are connected to form a phase, and the connection modes of the three-phase winding coils need to be completely the same to ensure that the motor circuits and magnetic circuits of each phase are consistent.

4. A switched reluctance machine according to claim 1, characterised in that: Each phase winding adopts a pulse power supply mode.

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