CN102497077A - Rotor slotless switched reluctance motor - Google Patents

Abstract

The invention discloses a rotor cogging-free switched reluctance motor, which belongs to the field of electromechanical switched reluctance motors, and in particular relates to a rotor cogging-free switched reluctance motor. The stator of the rotorless cogging switched reluctance motor adopts a magnetic pole structure with a combination of main magnetic poles and auxiliary magnetic poles. The rotor adopts an anisotropic axial lamination structure. The rotor is stacked into a 4-pole structure. The structure consists of a rotating shaft, a non-magnetically permeable bracket, an axial lamination, a non-magnetically permeable filling material and a non-magnetically permeable fastening ring. The axial laminated magnetic poles are made of silicon steel sheets of high magnetic permeability and non-magnetic insulating material laminations alternately laminated along the axial direction. The invention adopts the combination of stator magnetic poles and axial laminated rotors to greatly shorten the length of the magnetic circuit. It can reduce the iron loss of the switched reluctance motor, and effectively reduce the torque ripple of the switched reluctance motor; only the main magnetic pole is wound with windings, which is convenient for embedding the windings, no need to consider the phase-to-phase insulation problem, and the slot utilization rate is high.

Description

A rotor coggingless switched reluctance motor

technical field

The invention belongs to the field of electromechanical switched reluctance motors, and in particular relates to a rotor-free switched reluctance motor composed of a combined magnetic pole stator and an axially laminated rotor.

Background technique

The switched reluctance motor transmission system is a mechatronic AC speed control system, which has many advantages such as simple structure, reliable operation, flexible system control, good speed control performance, and high operating efficiency. It is especially suitable for harsh environments and ultra-high speed applications. Therefore, it is widely used in coal mines, aviation, automobiles and other fields. The power range is from several watts to several megawatts, and the speed range is from several to tens of thousands of revolutions. The traditional switched reluctance motor has a double-salient pole structure. There is neither winding nor permanent magnet on the rotor. Concentrated windings are wound on the stator. The windings on the radially opposite magnetic poles are connected in series to form a phase. Switched reluctance motors can be designed into single-phase, two-phase, three-phase and multi-phase different structures, and have single-tooth per pole and multi-tooth per pole structures. The double salient pole structure and switching power supply of traditional switched reluctance motors lead to its It has certain disadvantages: first, the marginal flux generated before the stator teeth and rotor teeth overlap causes current nonlinearity; second, the torque on the rotor of the switched reluctance motor is superimposed by a series of pulse torques. Moment is not a constant value. These will lead to the inherent torque ripple of the switched reluctance motor, especially when the motor is running at low speed, the torque ripple is large. Therefore, minimizing the torque ripple from the motor itself has become an important research content in the field of switched reluctance motors.

Contents of the invention

The technical problem to be solved in the present invention is to invent a switched reluctance motor with no cogging in the rotor, which breaks through the double salient pole category of the traditional switched reluctance motor structurally, and changes the defect of the torque ripple of the traditional switched reluctance motor from the characteristic , from making the switched reluctance motor a high-performance servo drive system.

The technical solution adopted in the present invention is a rotor-less cogging switched reluctance motor. The stator of the rotor non-cogging switched reluctance motor adopts a magnetic pole structure with a combination of main magnetic poles and auxiliary magnetic poles, and the rotor adopts an anisotropic axial lamination structure. The rotor of the rotor cogging-free switched reluctance motor is stacked into a 4-pole structure, the main pole of the stator is 6 poles, the auxiliary pole of the stator is also 6 poles, the number of poles of the stator and the rotor is 12/4 poles, and the motor is 3 phases; the stator core is 1 6 main magnetic poles 1-U1, 1-U2, 1-V1, 1-V2, 1-W1, 1-W2 are respectively wound with 6 windings 2-U1, 2-U2, 2-V1, 2-V2 , 2-W1, 2-W2, in order to improve the structural characteristics of the magnetic circuit, there are 6 auxiliary magnetic poles 1-a1, 1-a2, 1-a3, 1-a4, 1-a5, 1-a6; the U phase winding is composed of The two windings 2-U1 and 2-U2 on the two main magnetic poles 1-U1 and 1-U2 that are radially opposite in space are connected in series, and the V-phase winding is composed of the two main magnetic poles 1-V1 and 1-V1 that are radially opposite in space. The two windings 2-V1 and 2-V2 on 1-V2 are connected in series, and the W-phase winding consists of two windings 2-W1 and 2 on the two main magnetic poles 1-W1 and 1-W2 that are radially opposite in space. -W2 is connected in series to form the stator U, V, W three-phase winding; the rotor of the motor adopts an anisotropic axial lamination structure, which includes a rotating shaft 3, a non-magnetic support 4, and an axial lamination 5. The non-magnetic filling material 6 and the non-magnetic fastening ring 7 are composed; the axial lamination 5 is made of high magnetic permeability material silicon steel sheets and non-magnetic insulation material laminations laminated alternately in the axial direction, and the conduction is controlled. The thickness ratio of the magnetic lamination to the non-magnetic lamination is 10:1.

Let the polar arc angle of the auxiliary magnetic pole be βs2, and the pole arc angle of the main magnetic pole be βs1, in degrees; the relationship between the auxiliary magnetic pole and the main magnetic pole satisfies the following conditions:

β _s2 = (0.5～0.8) β _s1 (1)

Set the total pole arc angle of the sub-poles as β _s , then, β _s = β _s1 + β _s2 (2)

The relationship between the total pole arc angle of the rotor and stator poles is β _r > β _s (3)

The maximum groove depth h of axial laminations should satisfy h≥20δ (4)

where δ is the length of the air gap in mm.

The present invention has following remarkable effect:

1) The combined stator poles and anisotropic axial laminated rotor can effectively reduce the volume and torque ripple of the switched reluctance motor, and greatly shorten the length of the magnetic circuit, which can reduce the iron loss of the switched reluctance motor .

2) Since the stator poles are divided into main poles and auxiliary poles, and only the main poles are wound with windings, it is more convenient to embed the windings, without considering the phase-to-phase insulation problem, and the slot utilization rate is high.

3) Since the rotor adopts an anisotropic axial laminated rotor structure, the salient pole ratio of the rotor is high, which can effectively reduce the volume of the motor.

Description of drawings

Figure 1 is the stator structure diagram of the rotor cogging switched reluctance motor, in which, 1 is the stator core, 1-U1, 1-U2, 1-V1, 1-V2, 1-W1, 1-W2 are 6 main Magnetic poles, 1-a1, 1-a2, 1-a3, 1-a4, 1-a5, 1-a6 are 6 auxiliary magnetic poles, βs1, βs2 are respectively the central angles of the main magnetic pole and auxiliary magnetic pole arc, called Pole arc angle, unit is degree; 2-U1, 2-U2, 2-V1, 2-V2, 2-W1, 2-W2 are 6 stator windings.

Fig. 2 is the substructure diagram of the rotor of the rotor cogging switched reluctance motor, in which, 3 is the rotating shaft, 4 is the non-magnetic bracket, 5 is the axial lamination magnetic pole, 5a is the top of the axial lamination magnetic pole, and 6 is the non-magnetic pole. Magnetic filling material, 7 is a non-magnetic fastening ring; βr is the pole arc angle of the rotor magnetic pole, the unit is degree, h is the groove depth of the rotor magnetic pole, the unit is m.

Fig. 3 shows the magnetic field distribution of the main magnetic pole and the axial laminated pole top 5a of the axial laminated pole 5 in the non-aligned position when the U-phase winding is energized.

Fig. 4 shows the magnetic field distribution of the main magnetic pole and the axial laminated pole top 5a of the axial laminated pole 5 in the aligned position when the U-phase winding is energized.

Fig. 5 is a moment-angle characteristic curve of a 200W 3-phase 12/4-pole rotor without cogging switched reluctance motor, where the abscissa is the rotor position angle θ, the unit is degree, and the stator main poles 1-U1, 1- The misalignment position between U2 and the axial laminated magnetic pole top 5a of the rotor axial laminated magnetic pole 5 is θ=0°; the ordinate is the electromagnetic torque T of the motor, and the unit is N·m.

Detailed ways

The specific implementation of the present invention will be described in detail below in conjunction with the accompanying drawings and technical solutions. The stator of the rotorless cogging switched reluctance motor adopts a combined magnetic pole structure, and the rotor adopts an anisotropic axial lamination structure. Considering the manufacturability of the axial lamination, the rotor is stacked into a 4-pole structure. According to the constraint relationship of the stator and rotor poles of the switched reluctance motor, the main poles of the stator are selected as 6 poles, and the number of auxiliary poles of the stator is determined accordingly, which is also 6 poles, so the poles of the stator and rotor are 12/4 poles. According to the relationship between the number of poles and the number of phases, the motor has 3 phases. The invented 3-phase 12/4-pole rotor slotless switched reluctance motor consists of a stator and a rotor, and the stator includes two parts: a stator core 1 and a stator winding 2 . The stator core 1 has 6 main magnetic poles 1-U1, 1-U2, 1-V1, 1-V2, 1-W1, 1-W2 and 6 auxiliary magnetic poles 1-a1, 1-a2, 1-a3, 1- a4, 1-a5, 1-a6; 6 windings 2-U1, 2- U2, 2-V1, 2-V2, 2-W1, 2-W2; the U-phase winding consists of two windings 2-U1, 2- U2 is connected in series, the V-phase winding is composed of two windings 2-V1 and 2-V2 on the two main magnetic poles 1-V1 and 1-V2 that are radially opposite in space, and the W-phase winding is composed of The two windings 2-W1 and 2-W2 on the two opposite main magnetic poles 1-W1 and 1-W2 are connected in series to form a U, V and W three-phase winding. There are no windings on the six auxiliary magnetic poles 1-a1, 1-a2, 1-a3, 1-a4, 1-a5, 1-a6, see accompanying drawing 1. As shown in Figure 2, the rotor is an anisotropic axial lamination structure, which consists of a rotating shaft 3, a non-magnetic support 4, an axial lamination 5, a non-magnetic filling material 6 and a non-magnetic fastening ring 7, wherein , βr is the pole arc angle of the rotor pole, the unit is degree; h is the groove depth of the rotor pole, the unit is m. The axial lamination 5 is made of silicon steel sheet of high magnetic permeability material and lamination of non-magnetic insulating material laminated alternately in the axial direction, and the thickness ratio of the magnetic permeable lamination and the non-magnetic lamination is controlled to be 10:1. The salient pole ratio of the invented rotor coggingless switched reluctance motor is close to that of the traditional double salient pole switched reluctance motor.

As shown in Figure 3, the main magnetic pole in the non-cogging switched reluctance motor and the axial laminated pole top 5a of the axial laminated pole 5 are in the misaligned position, so that the U-phase winding is energized, and the U-phase winding 2-U1 The generated magnetic field lines pass through the U-phase magnetic pole 1-U1 and its adjacent auxiliary magnetic poles 1-a1, 1-a6 and main magnetic poles 1-V1, 1-W2 through the air gap and enter the axial laminated rotor to form a closed loop. The magnetic field lines generated by the U-phase winding 2-U2 pass through the U-phase magnetic pole 1-U2 and its adjacent auxiliary magnetic poles 1-a3, 1-a4 and main magnetic poles 1-V2, 1-W1 through the air gap and enter the axial laminated rotor , forming a closed loop. When the magnetic force lines enter the rotor from the stator through the air gap, they are twisted, and the tangential force generated by the twisted magnetic force lines drives the rotor to rotate. The auxiliary magnetic poles 1-a1, 1-a6, 1-a3, 1-a4 shorten the closed path of the magnetic force line when the U phase is energized; at the same time, when the axially laminated rotor poles pass through the auxiliary magnetic poles, due to the axially laminated rotor magnetic poles The anisotropic magnetic conduction characteristic distorts the magnetic lines of force, thereby increasing the torque range of the motor; when the motor rotates counterclockwise, the auxiliary magnetic poles 1-a1 and 1-a4 work; when the motor rotates clockwise, the auxiliary poles Pole 1-a3 and 1-a6 are active; keep energizing the U-phase winding and the motor will rotate to the aligned position, i.e. the main pole in a non-cogging switched reluctance motor and the axial lamination pole of axial lamination pole 5 The top 5a is in the aligned position, as shown in FIG. 4 . At this time, cut off the current of the U-phase winding and energize the other phase windings, and the motor will continue to generate tangential electromagnetic force to rotate; in this way, the energization state of each phase winding will be changed in turn, so that the motor will continue to rotate; if the power-on sequence is U-V-W-U, the motor will reverse Clockwise rotation; if the power-on sequence is U-W-V-U, the motor rotates clockwise.

The total pole arc angle of the stator pole is β _s = β _s1 + β _s2 , for a motor with 12 poles, the value of the stator pole arc angle βs is

The relationship between stator and rotor pole arc angles is β _r > β _s , take

β _r ≥ 32° (6)

In order to distribute the magnetic flux density of the motor reasonably, the width of the auxiliary magnetic poles of the stator should be equal to the width of the main magnetic poles. However, from the perspective of increasing the torque generation area and controlling the full rate of the slot, the width of the auxiliary magnetic poles should not be too wide. Comprehensive consideration These two factors should make the pole arc angle of the auxiliary magnetic pole and the main magnetic pole satisfy β _s2 = (0.5～0.8) β _s1 , so

β _s1 = 16°～20° (7)

β _s2 = 10°～16° (8)

For axial laminated rotors, in order to ensure a reasonable distribution of magnetic force lines, the maximum groove depth h of axial laminates should satisfy the following relationship

h≥20δ (9)

where δ is the length of the air gap in mm.

The main dimensions of the invented rotorless switched reluctance motor are similar to those of traditional switched reluctance motors. For a rotorless switched reluctance motor with a rated power of 200W and a rated speed of 1500r/min, the outer diameter of the stator is taken as D _s ＝120mm, rotor outer diameter D _r ＝60mm, air gap length δ＝0.3mm, taking stator arc angles as β _s1 =20°, β _s2 =10°, β _s =30°, rotor arc angle is β _r =32°. Compared with the traditional 6/4-pole switched reluctance motor with the same size, its output torque is similar, see Table 1. Figure 5 is a torque-angle characteristic curve of a 200W 3-phase 12/4-pole rotor without cogging switched reluctance motor. From the curve in the figure, it can be seen that the flat top part of the output torque is widened, and the change is small with the position angle. Therefore, the ripple of torque can be greatly reduced.

Table 1 Comparison of 200W prototypes

The torque ripple is improved by adopting the axial laminated rotor switched reluctance motor of the present invention, and the efficiency of the motor is greatly improved. The structure of the invention can be used to manufacture two-phase, three-phase, four-phase or five-phase rotor-less switched reluctance motors with different phase numbers.

Claims (1)

1. A rotor-less cogging switched reluctance motor, characterized in that the stator of the rotor non-cogging switched reluctance motor adopts a magnetic pole structure in which main magnetic poles and auxiliary magnetic poles are combined, the rotor adopts an anisotropic axial lamination structure, and the rotor The rotor of the non-cogging switched reluctance motor is stacked into a 4-pole structure, the main pole of the stator is 6 poles, the auxiliary pole of the stator is also 6 poles, the poles of the stator and the rotor are 12/4 poles, and the motor is 3 phases; the stator core (1 ) are wound with 6 windings (2-U1, 2-U2, 2-V1 , 2-V2, 2-W1, 2-W2), in order to improve the structural characteristics of the magnetic circuit, there are 6 auxiliary magnetic poles (1-a1, 1-a2, 1-a3, 1-a4, 1-a5, 1-a6) ; The U-phase winding is composed of two windings (2-U1, 2-U2) connected in series on the two main magnetic poles (1-U1, 1-U2) that are radially opposite in space, and the V-phase winding is composed of two windings (2-U1, 2-U2) in the space radial direction The two windings (2-V1, 2-V2) on the two opposite main magnetic poles (1-V1, 1-V2) are connected in series, and the W-phase winding is composed of two main magnetic poles (1- Two windings (2-W1, 2-W2) on W1, 1-W2) are connected in series to form three-phase windings of stator U, V, and W; the rotor of the motor adopts an anisotropic axial lamination structure, and the axial The lamination structure consists of a rotating shaft (3), a non-magnetic bracket (4), an axial lamination (5), a non-magnetic filling material (6) and a non-magnetic fastening ring (7); the axial lamination ( 5) It is made of silicon steel sheets of high magnetic permeability material and laminations of non-magnetic insulating material laminated alternately in the axial direction, and the thickness ratio of the magnetic permeable lamination and the non-magnetic lamination is controlled to be 10:1; Let the pole arc angle of the auxiliary magnetic pole be βs2, and the pole arc angle of the main magnetic pole be βs1 in degrees; the relationship between the auxiliary magnetic pole and the main magnetic pole arc angle satisfies the following conditions: β _s2 = (0.5～0.8) β _s1 (1) Set the total pole arc angle of the sub-poles as βs, then, β _s = β _s1 + β _s2 (2) The relationship between the total pole arc angle of the rotor and stator poles is: β _r > β _s (3) The maximum groove depth h of axial laminations should satisfy: h≥20δ (4) In the formula, δ is the air gap length in mm.

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