Hybrid excitation switched reluctance machine combining axial and radial air gaps

Abstract

The application relates to the technical field of electric machines, in particular to a hybrid excitation type switched reluctance motor combining axial and radial air gaps, which comprises a stator, a rotor, winding coils and permanent magnets, the stator comprises a stator yoke and stator poles with salient pole structures, the stator poles are divided into excitation poles and auxiliary poles, the permanent magnets are arranged between adjacent excitation poles and auxiliary poles, the rotor is coaxially nested in the interior of the stator, the rotor comprises a magnetic isolation sleeve and rotor blocks with salient pole structures, the inner surfaces of the stator poles and the outer surfaces of the rotor blocks are both provided with rectangular teeth, and the rectangular teeth of the stator poles and the rectangular teeth of the rotor blocks are gap matched to form axial and radial mixed air gaps. The hybrid stator poles, the blocked rotor and the axial and radial mixed air gap structure are adopted, and the permanent magnets are installed between the stator poles to perform auxiliary excitation, so that the output torque density and the efficiency of the switched reluctance motor are greatly improved, and the problems of low output torque density and low efficiency of the traditional switched reluctance motor are effectively solved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electric machines, in particular to a hybrid excitation switched reluctance motor combining axial and radial air gaps. BACKGROUND

[0002] With the further improvement of the performance and the reduction of the use cost of rare earth permanent magnet materials, permanent magnet motors have become the main choice of the new generation of driving motors, but the rotors of the permanent magnet motors have the problems of difficulty in protection and heat dissipation, poor high-temperature resistance and the like, which limit the application of the permanent magnet motors in occasions requiring a wide temperature range or a wide speed regulation range. The switched reluctance motor has the advantages of simple structure, strong fault tolerance, high reliability, flexible control mode, low cost and suitability for application in harsh working conditions, and is widely applied in many fields such as household appliances, electric vehicles and aerospace. SUMMARY

[0003] The application aims to provide a hybrid excitation switched reluctance motor combining axial and radial air gaps, which greatly improves the output torque density and efficiency of the switched reluctance motor by adopting a hybrid stator pole, a split rotor and an axial-radial hybrid air gap structure and installing permanent magnets between the stator poles for auxiliary excitation, and effectively solves the problem of low output torque density and efficiency of the traditional switched reluctance motor.

[0004] To achieve the above-mentioned purpose, the application provides a hybrid excitation switched reluctance motor combining axial and radial air gaps, which comprises a stator, a rotor, a winding coil and a permanent magnet, the stator comprises a stator yoke and a stator pole with a salient structure, the stator pole is divided into an excitation pole and an auxiliary pole, the excitation pole and the auxiliary pole are arranged uniformly and alternately on the inner side of the circumference of the stator yoke, the winding coil is sleeved on the excitation pole, the permanent magnet is arranged between the adjacent excitation pole and auxiliary pole, the rotor is coaxially nested in the interior of the stator, the rotor comprises a magnetic separation sleeve and a rotor block with a salient structure, the rotor block is concentrically and equidistantly arranged on the outer side of the circumference of the magnetic separation sleeve, the inner surface of the stator pole and the outer surface of the rotor block are both provided with a rectangular tooth, and the rectangular tooth of the stator pole and the rectangular tooth of the rotor block are gap-fitted to form an axial-radial hybrid air gap.

[0005] Preferably, the number of the stator poles is twelve, including six excitation poles and six auxiliary poles.

[0006] Preferably, the number of the rotor blocks is eight, the side of the rotor block close to the magnetic separation sleeve is provided with a dovetail-shaped protrusion, the outer side of the circumference of the magnetic separation sleeve is provided with a plurality of dovetail-shaped grooves, and the dovetail-shaped protrusion is embedded into the dovetail-shaped grooves.

[0007] Preferably, the pole arc of the excitation pole is greater than twice the pole arc of the auxiliary pole, the sum of the pole arcs of the excitation pole and the auxiliary pole is less than the included angle between the axes of two adjacent auxiliary poles, and the pole arc of the rotor block is greater than the included angle between the axis of the auxiliary pole and the axis of the adjacent excitation pole and is less than a rotor pole pitch.

[0008] Preferably, the excitation pole and the auxiliary pole are provided with fixing grooves on both sides, and the two ends of the permanent magnet are respectively inserted and connected in the adjacent two fixing grooves.

[0009] Preferably, the stator comprises a plurality of stator modules, one side of the stator module is provided with an arc-shaped groove, the other side of the stator module is provided with an arc-shaped protrusion, and the arc-shaped protrusions and the arc-shaped grooves of the adjacent two stator modules are inserted and connected.

[0010] Preferably, the winding coil adopts a concentrated winding, and the number of turns and the winding direction of the winding coil on each excitation pole are the same.

[0011] Preferably, the winding coil is divided into three phases, the winding coils on the axially symmetrical excitation poles are connected to form one phase, and the connection modes of the three-phase winding coils are completely the same.

[0012] Preferably, the axial length of the permanent magnet is the same as the axial length of the whole motor, the permanent magnet is tangentially magnetized, one end in contact with the excitation pole is N-pole, and the other end in contact with the auxiliary pole is S-pole.

[0013] Preferably, the shaft-diameter hybrid air gap comprises an axial air gap and a radial air gap.

[0014] The beneficial effects of the present application are as follows:

[0015] (1) The hybrid excitation switched reluctance motor combined with axial and radial air gaps is adopted, the hybrid stator pole, the block rotor and the shaft-diameter hybrid air gap structure are adopted, the permanent magnet is installed between the stator poles to assist excitation, the magnetic flux path of the motor is shortened, the air gap reluctance is reduced, the excitation magnetic motive force is increased, the air gap flux utilization rate is improved, the air gap flux density is increased, and the motor loss is reduced, so that the output torque density and the efficiency of the motor are greatly improved, and the problems of low output torque density and low efficiency of the traditional switched reluctance motor are solved.

[0016] (2) The hybrid excitation switched reluctance motor combined with axial and radial air gaps is adopted, the permanent magnet is installed between the stator poles, the air gap flux density is increased, the magnetic saturation in the stator is reduced, the output torque density and the efficiency of the motor are improved, and the overload capacity of the motor is also improved.

[0017] The permanent magnet is installed between the stator poles and is not affected by the rotating speed of the rotor, heat of the permanent magnet can be dissipated through the stator, the heat dissipation mode is simple, even if the permanent magnet is demagnetized or damaged, the motor can still keep running without shutdown, therefore, the motor has higher reliability and fault tolerance, and can be applied to occasions requiring high temperature range and wide speed regulation range to replace the permanent magnet motor.

[0018] (3) The mixed excitation switched reluctance motor combined with axial and radial air gaps has a special matching relationship between the number of stator poles and the number of rotor blocks, so that the positive torques generated by different rotor blocks are crossed, the torque generation area is widened, and the torque pulsation of the motor is reduced.

[0019] (4) The mixed excitation switched reluctance motor combined with axial and radial air gaps adopts concentrated winding and modularization of the stator, the winding process and the assembly process between the stator and the rotor are simplified, the assembly cost of the motor is reduced, and the industrial production of the motor is beneficial.

[0020] The technical solutions of the present application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a whole schematic view of a mixed excitation switched reluctance motor combined with axial and radial air gaps of the present application;

[0022] Figure 2 is an axial sectional view of a mixed excitation switched reluctance motor combined with axial and radial air gaps of the present application;

[0023] Figure 3 is a schematic view of a stator structure of a mixed excitation switched reluctance motor combined with axial and radial air gaps of the present application;

[0024] Figure 4 is a partial enlarged view of a permanent magnet fixing groove of a mixed excitation switched reluctance motor combined with axial and radial air gaps of the present application;

[0025] Figure 5 is a schematic view of a rotor structure of a mixed excitation switched reluctance motor combined with axial and radial air gaps of the present application;

[0026] Figure 6 is a partial enlarged view of an air gap of a mixed excitation switched reluctance motor combined with axial and radial air gaps of the present application;

[0027] Figure 7 is a schematic view of winding connection and permanent magnet polarity distribution of a mixed excitation switched reluctance motor combined with axial and radial air gaps of the present application;

[0028] Figure 8This is a schematic diagram of the no-load magnetic flux path of a hybrid excitation switched reluctance motor combining axial and radial air gaps according to the present invention.

[0029] Figure 9 This is a schematic diagram of the load flux path of a hybrid excitation switched reluctance motor combining axial and radial air gaps according to the present invention (phase A is conducting);

[0030] Figure 10 This is a schematic diagram showing the overlap of the stator pole and rotor pole of phase A in a hybrid excitation switched reluctance motor with axial and radial air gaps under different rotor position angles according to the present invention. Figure 10 In the diagram, 'a' represents the rotor position I. Figure 10 b in the diagram is a schematic diagram of rotor position II.

[0031] Figure label:

[0032] 1. Stator; 11. Excitation pole; 12. Auxiliary pole; 13. Stator yoke; 14. Fixing slot;

[0033] 2. Winding coil; 3. Rotor; 31. Rotor block; 32. Magnetic shielding sleeve; 33. Dovetail protrusion; 34. Dovetail groove;

[0034] 4. Permanent magnet; 5. Arc-shaped groove; 6. Arc-shaped protrusion; 7. Rectangular tooth; 8. Mixed shaft-diameter air gap; 81. Axial air gap; 82. Radial air gap. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0036] Example

[0037] like Figures 1 to 2 As shown, this invention provides a hybrid excitation switched reluctance motor combining axial and radial air gaps, including a stator 1, a rotor 3, winding coils 2, and a permanent magnet 4. The stator 1 includes several stator 1 modules. One side of each stator 1 module has an arc-shaped groove 5, and the other side has an arc-shaped protrusion 6. The arc-shaped protrusions 6 of two adjacent stator 1 modules are inserted into the arc-shaped grooves 5. Modularizing the stator 1 reduces the assembly difficulty between the stator 1 and the rotor 3, and also simplifies the installation of the winding coils 2.

[0038] like Figure 3As shown in the figure, the stator 1 includes a stator yoke 13 and a stator pole of a salient pole structure, the stator pole is divided into a field pole 11 and an auxiliary pole 12, the number of the stator pole is twelve, including six field poles 11 and six auxiliary poles 12, the field poles 11 and the auxiliary poles 12 are evenly arranged in the circumferential inside of the stator yoke 13. In order to make the torque generated by the motor as large as possible, the pole arc of the field pole 11 is greater than twice the pole arc of the auxiliary pole 12; in order to ensure that the stator 1 has space to install the winding coil 2, the sum of the pole arcs of the field pole 11 and the auxiliary pole 12 is less than the included angle between the axes of two adjacent auxiliary poles 12.

[0039] As shown in the figure, Figure 4 The permanent magnet 4 is arranged between the adjacent field poles 11 and auxiliary poles 12, and the two sides of the field pole 11 and the auxiliary pole 12 are provided with fixing grooves 14, and the two ends of the permanent magnet 4 are respectively inserted and connected in the adjacent two fixing grooves 14. By means of the insertion and connection with the fixing grooves 14, the permanent magnet 4 is convenient to install and disassemble, so that when the permanent magnet 4 is demagnetized and damaged, it can be replaced. The axial length of the permanent magnet 4 is the same as the axial length of the whole motor, and the permanent magnet 4 is tangentially magnetized, wherein one end in contact with the field pole 11 is N pole and the other end in contact with the auxiliary pole 12 is S pole. The permanent magnet 4 is installed between the stator poles, and the permanent magnet 4 is not affected by the rotating speed of the rotor 3, and the heat can be dissipated through the stator core, so that the heat dissipation mode is simple. Even if the permanent magnet 4 is demagnetized or damaged, the motor can still keep running without stopping, so that the motor has higher reliability and fault tolerance, and can be applied in occasions requiring high temperature range and wide speed regulation range.

[0040] As shown in the figure, Figure 3 And Figure 7 The winding coil 2 adopts concentrated winding, the winding coil 2 is sleeved on the field pole 11, and there is no winding coil 2 wound on the auxiliary pole 12 in any form, and the auxiliary pole 12 only provides a return path for the magnetic flux generated by the winding coil 2. The number of turns and the winding direction of the winding coil 2 wound on each field pole 11 are the same. The winding coil 2 is divided into three phases, and the winding coils 2 on the axially symmetrical field poles 11 are connected to form a phase, such as the A-phase winding formed by the winding coils 2 on the P A1 field poles 11 and the winding coils 2 on the P A2 field poles 11, the B-phase winding formed by the winding coils 2 on the P B1 field poles 11 and the winding coils 2 on the P B2 field poles 11, and the C-phase winding formed by the winding coils 2 on the P C1 field poles 11 and the winding coils 2 on the P C2 field poles 11. The connection modes of the three-phase winding coils 2 are completely the same, which ensures the symmetry of the motor circuit and magnetic circuit.

[0041] As shown in the figure, Figure 5As shown, the rotor 3 is coaxially nested inside the stator 1. The rotor 3 includes a magnetic shielding sleeve 32 and rotor blocks 31 with salient pole structures. The rotor blocks 31 are concentrically and equally spaced on the outer circumference of the magnetic shielding sleeve 32. There are eight rotor blocks 31. The side of the rotor block 31 closest to the magnetic shielding sleeve 32 has a dovetail-shaped protrusion 33. The outer circumference of the magnetic shielding sleeve 32 has several dovetail-shaped grooves 34. The dovetail-shaped protrusion 33 is embedded in the dovetail-shaped grooves 34. In order to maximize the range of torque generated by the motor, the pole arc of the rotor block 31 is greater than the angle between the axis of the auxiliary pole 12 and the axis of the adjacent excitation pole 11 and less than one rotor pole pitch.

[0042] like Figure 2 and Figure 6 As shown, both the inner surface of the stator poles and the outer surface of the rotor block 31 are provided with rectangular teeth 7. The rectangular teeth 7 of the stator poles and the rectangular teeth 7 of the rotor block 31 are clearance-fitted to form a shaft-diameter mixed air gap 8. The shaft-diameter mixed air gap 8 includes an axial air gap 81 and a radial air gap 82. The motor adopts a shaft-diameter mixed air gap 8, which increases the overlap area of ​​the stator and rotor poles in the aligned position. Without changing the outer diameter, stack length, and air gap length of the motor, the magnetic reluctance of the air gap can be reduced, and the magnetic flux utilization rate of the air gap can be increased, thereby effectively improving the output torque density and efficiency of the motor.

[0043] like Figure 8 As shown, when no current flows through the winding coil 2, only the magnetic flux generated by the permanent magnet 4 exists in the motor. The magnetic flux generated by the permanent magnet 4 mainly forms a closed magnetic circuit through the excitation pole 11, stator yoke 13 and auxiliary pole 12 in contact with it. No matter how the rotor 3 changes position, the magnetic flux generated by the permanent magnet 4 hardly passes through the air gap, so the cogging torque generated by the motor when it is unloaded is close to zero.

[0044] like Figure 9 As shown, when current flows through phase A winding coil 2, the motor contains magnetic flux generated by permanent magnet 4 and magnetic flux generated by phase A winding coil 2. Since the direction of the magnetic flux generated by phase A winding coil 2 is completely opposite to the direction of the magnetic flux generated by permanent magnet 4 in the excitation pole 11, stator yoke 13, and auxiliary pole 12, they cancel each other out. Therefore, the magnetic flux generated by permanent magnet 4 can only pass downwards sequentially through the excitation pole 11 in contact with it, the shaft diameter mixing air gap 8, the rotor block 31, and the auxiliary pole 12 in contact with it to form a closed loop. Furthermore, since the direction of the magnetic flux generated by phase A winding coil 2 is completely opposite to the direction of the magnetic flux generated by permanent magnet 4 in its adjacent slot in the auxiliary pole 12, the magnetic flux generated by permanent magnet 4 in the slot adjacent to phase A winding coil 2 also forms a closed loop through the shaft diameter mixing air gap 8 and rotor block 31. These two magnetic fluxes, together with the magnetic flux generated by phase A winding coil 2, superimpose at the air gap, increasing the air gap magnetic flux density and significantly increasing the motor's output torque, thereby improving the motor's overload capacity and operating efficiency.

[0045] Therefore, by installing permanent magnets 4 between the stator poles, this invention not only increases the air gap magnetic flux density under the same excitation current but also reduces magnetic saturation in the stator 1. This not only improves the output torque density and efficiency of the motor but also enhances its overload capacity, solving the problems of low output torque density and low efficiency in switched reluctance motors and exploring a new path for the development of high-performance switched reluctance motors. Figure 10 As shown, when rotor 3 rotates counterclockwise, the rotor first rotates to rotor position I, and then to rotor position II. At rotor position I, P r1 and P r5 Rotor block 31 overlaps with both excitation pole 11 and auxiliary pole 12 simultaneously. At rotor position II, P r2 and P r6 Rotor block 31 overlaps with both excitation pole 11 and auxiliary pole 12 simultaneously. Therefore, when rotor 3 rotates counterclockwise, P r1 and P r5 Rotor block 31 first interacts with the stator poles to generate electromagnetic torque T1, P r2 and P r6 The rotor block 31 interacts with the stator pole to generate an electromagnetic torque T2. The electromagnetic torque generated by the A-phase winding is equal to T1 + T2. Since T1 and T2 are generated at different times, they overlap. This design helps to broaden the range of positive torque generated by the motor and reduce the torque pulsation of the motor.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A hybrid excitation switched reluctance motor combining axial and radial air gaps, characterized in that: The system includes a stator, rotor, winding coils, and permanent magnets. The stator consists of a stator yoke and stator poles with salient pole structures. The stator poles are divided into excitation poles and auxiliary poles, which are evenly and alternately arranged on the inner circumference of the stator yoke. The winding coils are sleeved on the excitation poles. The permanent magnets are arranged between adjacent excitation poles and auxiliary poles. The rotor is coaxially nested inside the stator. The rotor consists of a magnetic shielding sleeve and rotor blocks with salient pole structures. The rotor blocks are concentrically and equally spaced on the outer circumference of the magnetic shielding sleeve. The inner surface of the stator poles and the outer surface of the rotor blocks are provided with rectangular teeth. The rectangular teeth of the stator poles and the rectangular teeth of the rotor blocks are clearance-fitted to form a shaft-diameter mixed air gap. There are eight rotor blocks. The side of the rotor block near the magnetic shielding sleeve is provided with a dovetail-shaped protrusion. The outer circumference of the magnetic shielding sleeve is provided with several dovetail-shaped grooves. The dovetail-shaped protrusions are embedded in the dovetail-shaped grooves. The pole arc of the excitation pole is twice as large as that of the auxiliary pole. The sum of the pole arcs of the excitation pole and the auxiliary pole is less than the angle between the axes of two adjacent auxiliary poles. The pole arc of the rotor block is greater than the angle between the axis of the auxiliary pole and the axis of the adjacent excitation pole and less than one rotor pole pitch. Both sides of the excitation pole and the auxiliary pole are provided with fixing slots, and the two ends of the permanent magnet are respectively inserted into the two adjacent fixing slots; the axial length of the permanent magnet is the same as the axial length of the motor as a whole. The permanent magnet is tangentially magnetized, with the end in contact with the excitation pole being the N pole and the end in contact with the auxiliary pole being the S pole.

2. The hybrid excitation switched reluctance motor combining axial and radial air gaps according to claim 1, characterized in that: The stator has twelve poles, including six excitation poles and six auxiliary poles.

3. The hybrid excitation switched reluctance motor combining axial and radial air gaps according to claim 1, characterized in that: The stator includes several stator modules. One side of the stator module is provided with an arc-shaped groove, and the other side of the stator module is provided with an arc-shaped protrusion. The arc-shaped protrusions of two adjacent stator modules are inserted and connected to the arc-shaped groove.

4. A hybrid excitation switched reluctance motor combining axial and radial air gaps according to claim 1, characterized in that: The winding coil adopts a concentrated winding, and the number of turns and the winding direction of the winding coil are the same on each excitation pole.

5. A hybrid excitation switched reluctance motor combining axial and radial air gaps according to claim 1, characterized in that: The winding coil is divided into three phases. The winding coils on the axially symmetrical excitation poles are connected to form one phase. The connection method of the three-phase winding coils is exactly the same.

6. A hybrid excitation switched reluctance motor combining axial and radial air gaps according to claim 1, characterized in that: The shaft-diameter mixed air gap includes axial air gap and radial air gap.

Images