CN103178668B - Radial magnetic field double-stator vernier motor - Google Patents

Abstract

The invention discloses a radial magnetic field double-stator vernier motor, comprising: a rotor (2), which is in the form of a ring, and a plurality of permanent magnets are evenly spaced on the circumference of the ring; stators (1, 4), which are in the form of a circle Cylindrical, a plurality of grooves are evenly opened on the peripheral wall of the cylinder, each groove is used to accommodate windings, and the raised parts between the grooves form stator teeth; it is characterized in that the stator (1, 4) has a diameter of The two different ones are arranged coaxially, inner and outer, and the number of grooves on the two stators is the same. The rotor (2) is coaxially sleeved between the two stators (1, 4), and the inner stator The stator teeth of (4) and the stator teeth of the outer stator (1) are separated by half a slot pitch angle in the circumferential direction. When the torque density of the motor of the invention is similar to that of the traditional vernier motor, the power factor is significantly improved and can reach above 0.8.

Description

Radial Field Dual Stator Vernier Motor

technical field

The invention belongs to the field of motors, and in particular relates to a vernier motor, which is suitable for such as wind power generation, ship driving and the like.

Background technique

As a very important part of renewable energy, wind energy has been highly valued by countries all over the world including China. In the past few years, the installed capacity of wind power has increased by a large proportion for many consecutive years. Especially in China, wind power has become an important renewable energy industry. Among them, the wind turbine is one of the most critical components in the wind power generation system. Its design technology and production process have become the technological commanding heights of the competition among countries all over the world. Especially the direct drive wind turbine has low speed, large volume and heavy weight. , wind turbines with high power density can greatly reduce the weight and cost of wind turbines, and have great social and economic benefits.

The vernier motor (Vernier Machine) has received more and more attention from the industry in recent years. The topology of this motor has the advantages of ultra-high power density and simple mechanical structure, and it is expected to be applied in large-scale engineering. Since the torque of the motor is related to its no-load back EMF when the speed is constant, for a traditional motor, the number of pole pairs of the stator and the rotor is the same, so increasing the number of poles will reduce the stator flux linkage in the same proportion, Therefore, the no-load back EMF cannot be increased by increasing the number of poles.

As shown in Figure 1, the structure of the existing vernier motor is similar to that of ordinary permanent magnet motors, consisting of a rotor and a stator. It is several times of the number of stator pole pairs. Under the condition of constant speed, more rotor pole pairs can increase the alternating frequency of stator flux linkage. The reduction solves the contradiction that increasing the number of pole pairs of the traditional motor will reduce the stator flux linkage proportionally, so that the product of the flux linkage alternating frequency and the stator flux linkage can be increased, thereby increasing the no-load back EMF, and increasing the torque and power density.

The main disadvantage of the existing vernier motor is its low power factor, which leads to the need to increase the capacity of the drive converter for a given output power, which brings about problems such as increased cost and reduced system operation reliability. The reason for the low power factor of the vernier permanent magnet motor is related to the ratio of the main flux linkage and the product of the motor inductance and the phase current. Compared with the traditional motor, the vernier motor rotor has a large number of poles, which is close to the number of teeth. It can be seen from Figure 1 that a large amount of magnetic flux passes through the air gap from the magnetic pole directly through the stator teeth, and then returns to the other magnetic pole without passing through the stator winding. , which causes the leakage flux of the permanent magnets to increase greatly. At the same time, when one of the adjacent permanent magnets faces the stator teeth and the other faces the stator slot, the magnetic circuit formed by the adjacent permanent magnets has a large reluctance, resulting in a very large main flux. Low, so the existing vernier motor power factor is very low. In fact, in the case of using an electric load similar to that of the traditional permanent magnet motor, the power factor of the vernier motor in the prior art can be as low as 0.2-0.3, while the power factor of the traditional permanent magnet motor can reach above 0.90.

Contents of the invention

The present invention aims to propose a radial magnetic field double-stator vernier motor, through the arrangement of the rotor and the two stators and setting the relative positional relationship between the stator teeth and the rotor pole shoes, thereby improving the power factor and power density of the vernier motor and solving the current problem There is a problem of low operational reliability caused by low power factor of the vernier motor.

A radial magnetic field double stator vernier motor of the present invention comprises:

The rotor is in the shape of a ring, and a plurality of permanent magnets are arranged at intervals on the circumference of the ring;

The stator is in the shape of a cylinder, and there are multiple grooves on the peripheral wall of the cylinder, each groove is used to accommodate the winding, and the raised parts between the grooves form stator teeth;

It is characterized in that the stators are two with different diameters, and the two are arranged coaxially, inner and outer, and the number of grooves on the two stators is the same, and the rotor is coaxially sleeved between the two stators, and the inner fixed The stator teeth of the stator and the stator teeth of the outer stator are separated by half a slot pitch angle in the circumferential direction.

As an improvement of the present invention, the stator teeth of the inner stator are arranged opposite to the grooves of the outer stator.

As an improvement of the present invention, the groove of the inner stator is provided on the outer peripheral wall of the cylinder.

As an improvement of the present invention, the groove of the outer stator is provided on the inner peripheral wall of the cylinder.

As an improvement of the present invention, the permanent magnets are separated by pole shoes, and the pole shoes are connected by silicon steel bridges or non-magnetic conductive materials.

As an improvement of the present invention, bolt holes are provided on the pole pieces, and the rotor is connected to the torque tube through the bolt holes.

As an improvement of the present invention, the rotor is integrally formed, and the permanent magnets are housed in grooves arranged circumferentially on the rotor.

As an improvement of the present invention, the outer stator is fixed on the casing, and the inner stator is fixed by a stationary shaft or a frame arm.

As an improvement of the present invention, the rotating shaft is fixedly connected to the torque tube provided on the rotating shaft through an axial screw.

As an improvement of the present invention, the torque tube is a cantilever structure with one end fixed on the rotating shaft, or one end is fixed on the rotating shaft and the other end is relatively rotatably fixed and supported on the shaft through a bearing.

Structures on stationary axes.

The invention adopts a radial magnetic field double-stator structure, in which the rotor and the two stators are nested, and by setting the relative position relationship between the stator teeth and the rotor pole shoes, a compact motor structure is obtained, and the torque density of the traditional vernier motor is similar to the situation Under this condition, the power factor is significantly improved and can reach more than 0.8.

Description of drawings

Fig. 1 is a schematic structural view of a vernier motor in the prior art;

In Fig. 2, (a) is a three-dimensional structural schematic diagram of a radial magnetic field double-stator vernier permanent magnet motor according to an embodiment of the present invention; (b) is a schematic cross-sectional structure diagram of a radial magnetic field double-stator vernier permanent magnet motor according to an embodiment of the present invention;

Figure 3 (a)-(d) is a schematic diagram of four different rotor structures (1/4 model) of the radial magnetic field double-stator vernier permanent magnet motor according to the embodiment of the present invention;

4(a)-(d) are structural schematic diagrams of radial magnetic field double-stator vernier permanent magnet motors with four different rotor structures according to the embodiment of the present invention.

Fig. 5 is a schematic diagram of the application of the vernier motor in the direct drive wind power generation system according to the embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and effect of the present invention clearer, the present invention will be described in further detail below in conjunction with the accompanying drawings and specific examples. The following examples are only used to explain the present invention and do not constitute a limitation to the present invention.

As shown in Figure 2, the vernier motor of this embodiment includes two stators and a rotor, the two stators are respectively the inner stator 4 and the outer stator 1, the rotor 2 is in the middle of the outer stator 1 and the inner stator 4, and the three are concentric.

The motor topology of this embodiment contains double air gaps; the two stator windings 3 adopt single-phase or multi-phase windings (Figure 2 only shows the effective part of the winding, and the end part is not shown).

The rotor 2 permanent magnet is preferably built-in and tangentially magnetized. The magnetic field direction of the permanent magnet is shown by the arrow in Figure 2(b). Combination of the number of stator slots, the vernier motor in Fig. 2 of this embodiment preferably has 44 rotor poles, 4 stator poles and 24 slots.

The magnetic circuit of adjacent magnetic poles of the vernier motor in this embodiment is as follows: first, the yoke of the inner stator 4 passes through the teeth of the inner stator 4, then passes through the air gap between the inner stator 4 and the rotor 2, and then passes through the pole shoe and The air gap between the outer stator 1 and the rotor 2, and the teeth of the outer stator 1 to the yoke of the outer stator 1.

The vernier motor of this embodiment adopts a double-sided stator, and the difference between the inner stator teeth and the outer stator teeth is half a slot pitch angle, that is, the inner stator teeth are opposite to the outer stator slots, and because the number of rotor poles is similar to the number of stator teeth, when the motor is stationary, The inner stator teeth and the outer stator teeth are respectively opposite to adjacent pole pieces. As shown in Figure 2(b), compared with the traditional vernier motor, the double-stator structure utilizes half a slot pitch in the position of the inner stator and the outer stator structure, so that the teeth of the inner stator and the teeth of the outer stator cooperate to form the main flux linkage , and the magnetic circuit reluctance is small, and the main magnetic field is enhanced, which solves the problem that the adjacent magnetic poles of the vernier motor are composed of stator teeth and slots to form a magnetic circuit with large reluctance and leakage flux, which greatly reduces the leakage flux. In addition, the use of magnets The placement method realizes the magnetic concentration effect, which greatly improves the main magnetic flux and the utilization rate of the permanent magnet, which strengthens the magnetic field of the permanent magnet of the vernier motor, increases its torque output capability, and greatly improves its power factor.

The present invention adopts a double-stator structure, and its mechanical structure is relatively complicated. The design of the mechanical structure not only affects the operational reliability of the present invention, but also affects the electromagnetic performance of the present invention.

The rotor magnet of the present invention adopts circumferential magnetization. Figure 3 shows four different rotor mechanical structures. The pole shoes of the rotor shown in Figure 3 (a) are connected by narrow silicon steel bridges. There are bolt holes on the pole shoes, bolt holes The number of them is variable; the rotor is connected to the torque tube through these axial bolts. Due to the narrow silicon-steel bridge of this structure, the leakage magnetic circuit formed has a large reluctance, which can reduce the leakage flux of the permanent magnet.

Figure 3(b) has no axial bolt holes compared with (a), and the other parts have the same structure; with this structure, since there are no bolt holes, the main magnetic circuit will not be affected by the bolt holes, but the mechanical stability of the rotor is not as good as ( a).

In the structure shown in Figure 3(c), each pole piece can be connected by non-magnetic materials such as epoxy resin. With this structure, there is no silicon steel bridge, and the magnetic flux leakage of the permanent magnet is small, which increases the utilization rate of the permanent magnet and improves the rotation speed. Torque output capacity;

Figure 3(d) The rotor is integrated, and the permanent magnets are placed in the slots opened on the rotor. This structure has good mechanical stability, but the magnetic flux leakage is relatively large.

The above rotor structures are only schematic structures, and the present invention is not limited to these structures, and other similar structural transformations are within the protection scope of the present invention.

The double-stator vernier permanent magnet motor contains double stators and a rotor, and its mechanical structure is relatively complicated. Figure 4 shows four schematic mechanical structures, the present invention is not limited to these mechanical structures, and other similar structures are also within the protection scope of the present invention. Figure 4(a) is a cantilever beam structure, the rotor 2 and the torque tube are connected by axial screws, the torque tube is in the form of a cantilever beam, which is fixed on the rotating shaft 6, and the outer stator 1 is fixed on the casing 7, The inner stator 4 is fixedly arranged on the stationary shaft 5 through a support frame. In Figure 4(b), the rotor 2 is supported on both sides of the axial direction, that is, the rotor 2 is connected by axial screws through the torque tube and then fixed by the support frames at both ends of the axial direction. The outer stator 1 is fixed on the casing 7, and the inner stator 1 The child 4 is fixedly arranged on the stationary shaft 5 by a support frame. In Fig. 4(c), the inner stator 4 is placed on the frame arm 8, which is fixedly arranged on the casing 7. At this time, no stationary shaft is needed, and the rotor structure is similar to that in Fig. 4(a). The stator structure in Fig. 4(d) is the same as that in Fig. 4(a). The effective part of the rotor 2 is connected to the torque tube through the pressure of two bearings. In this structure, there is no need to drill bolt holes on the pole pieces of the rotor.

As an electromechanical energy conversion device, the generation of motor torque can be attributed to the interaction between the stator's rotating magnetic field and the rotor's magnetic field to drive the rotor to rotate (motor). In order to generate constant torque, the number of poles of the two rotating magnetic fields must be the same. The vernier motor can realize its function only if the sum of the pole pairs of the stator and rotor is equal to the number of slots. Specifically, the magnetic field generated by the permanent magnets of the rotor interacts with the slots of the stator to generate many harmonics of the magnetic field. , the harmonic magnetic field with the same number of stator poles has a large content. At this time, the harmonic magnetic field interacts with the magnetic field generated by the stator to generate a constant torque, thereby realizing power generation.

The radial vernier motor of the present invention can be applied in a direct-drive wind power generation system, as shown in Figure 5, it is a direct-drive wind power generation system based on a radial magnetic field double-stator vernier motor, which consists of wind blades and radial magnetic field double stators Composed of vernier generator, rectifier, DC bus, and inverter. Of course, the application of the radial magnetic field double-stator vernier generator in the field of wind power is not limited to the above-mentioned systems, and can also be used in conjunction with different wind power systems. The vernier motor of the present invention can also be used in other power system fields such as the electric propulsion field of ships.

Claims (3)

1. A radial magnetic field double stator vernier motor, comprising: The rotor (2) is in the shape of a ring, and a plurality of permanent magnets are arranged at intervals on the circumference of the ring; The stator (1, 4) has a cylindrical shape, and a plurality of grooves are uniformly opened on the peripheral wall of the cylinder, and each groove is used to accommodate the winding, and the protrusions between the grooves on the peripheral wall of the cylinder form the stator teeth ; It is characterized in that the stators (1, 4) are two with different diameters, and the two are arranged in a coaxial inner and outer sleeve, the number of grooves on the two stators (1, 4) is the same and the number of poles is the same, the The rotor (2) is coaxially sleeved between the two stators (1, 4), wherein the stator teeth of the inner stator (4) are arranged opposite to the grooves of the outer stator (1), and the stator teeth of the inner stator (4) The stator teeth of the outer stator (1) are at a distance of half a slot pitch angle in the circumferential direction, so that the teeth of the inner stator and the teeth of the outer stator cooperate to form the main magnetic chain; wherein, the grooves of the inner stator (4) are provided in the cylinder On the peripheral wall of the outer body, the groove of the outer stator (1) is provided on the inner peripheral wall of the cylinder, the permanent magnets are separated by pole shoes, and the pole shoes are connected by silicon steel bridges or non-magnetic materials, and the pole shoes are Bolt holes are provided, and the rotor (2) is connected to the torque tube through the above bolt holes; The outer stator (1) is fixed on the casing, the inner stator (4) is fixed by the stationary shaft (5) or the frame arm (8), and the rotor (2) is connected to the shaft of the motor by axial screws The torque tube on (6) is fixedly connected, and the torque tube is a cantilever structure with one end fixed on the motor shaft (6), or one end is fixed on the motor shaft (6) and the other end is relatively rotatable through a bearing A gate-shaped structure fixedly supported on a stationary shaft (5). 2. A radial magnetic field double-stator vernier motor according to claim 1, wherein the rotor (2) is integrally formed, and the permanent magnets are accommodated in concave holes arranged at uniform intervals in the circumferential direction of the rotor (2). in the slot. 3. The application of the radial magnetic field double-stator vernier motor according to claim 1 or 2 in a wind power generation system or a ship power system.