CN117239969B - Outer rotor variable magnetic flux alternating pole permanent magnet synchronous motor - Google Patents

Abstract

The invention relates to the technical field of motors, and particularly discloses an outer rotor variable magnetic flux alternating pole permanent magnet synchronous motor which comprises an inner stator and an outer rotor, wherein the inner stator comprises a stator core, an armature winding, a stator yoke and a direct current magnetic regulating winding, wherein the stator core is symmetrically arranged, the armature winding is arranged on the stator core, the stator yoke is arranged in the stator core, and the direct current magnetic regulating winding is arranged between the two stator cores; wherein the inner surface of the outer rotor is uniformly provided with memory permanent magnets at intervals along the circumferential direction. According to the invention, after the traditional permanent magnets with alternating poles are replaced by the memory permanent magnets, the combination of the memory permanent magnets and the direct-current magnetic regulating windings can regulate the excitation magnetic field of the motor in real time. In the rated load state, the memory permanent magnet is completely magnetized, and the output performance of the motor system is not affected. In the weak magnetic state, the direct-current magnetic regulating winding is controlled to generate a direct-current pulse magnetic field to regulate the magnetism of the memory permanent magnet, so that the rotating speed range of the motor is further improved.

Description

An external rotor variable flux alternating pole permanent magnet synchronous motor

Technical field

This application relates to the field of motor technology, and specifically discloses an external rotor variable flux alternating pole permanent magnet synchronous motor.

Background technique

Alternating pole permanent magnet motors have received widespread attention in fields such as electric vehicles and aviation power generation due to their high permanent magnet material utilization.

Traditional alternating pole permanent magnet synchronous motors mostly use an outer stator-inner rotor topology, in which the rotor permanent magnet poles and core poles are alternately arranged along the circumference to form alternating magnetic poles. In order to suppress the eddy current losses caused by the air gap harmonic magnetic field in the rotor, the rotor core of traditional alternating pole permanent magnet synchronous motors is often made of laminated silicon steel sheets, and when the rotor permanent magnets are at high speed, additional auxiliary devices need to be added to protect the rotor. is destroyed, which greatly limits the application of alternating pole permanent magnet synchronous motors in the field of high-speed rotating machinery.

As a type of permanent magnet motor, the traditional alternating pole permanent magnet motor has the inherent defect that the permanent magnet magnetic field cannot be adjusted. The inherent high magnetic permeability characteristics of the alternating pole permanent magnet motor core enable it to be used as an electric excitation-permanent magnet hybrid excitation synchronous motor. The magnetic field generated by the electric excitation coil can be used to flexibly adjust the permanent magnet magnetic field to enhance the motor output performance and increase the motor speed range. However, when the electric excitation coil generates a continuous magnetic field, there is serious excitation copper loss, which increases the thermal load of the motor system. In severe cases, the motor insulation will be burned, reducing the reliability of the motor system. In addition, the non-negligible excitation copper loss reduces the energy conversion efficiency of the motor, which is not conducive to the efficient operation of the motor system.

Therefore, in view of this, the inventor provides an external rotor variable flux alternating pole permanent magnet synchronous motor in order to solve the above problems.

Contents of the invention

The purpose of the present invention is to improve the topological structure of the alternating pole permanent magnet motor, increase the rotor strength, and increase the motor speed range. In addition, by flexibly adjusting the no-load magnetic field of alternating pole permanent magnet synchronous motors, the high-efficiency operating range of this type of motors can be broadened.

In order to achieve the above object, the basic solution of the present invention provides an external rotor variable flux alternating pole permanent magnet synchronous motor, including an inner stator and an outer rotor, wherein the inner stator includes a symmetrically arranged stator core, and is provided on the stator core. The armature winding, the stator yoke located in the stator core and the DC magnetizing winding located between the two stator cores.

The outer rotor is located outside the inner stator, and the inner surface of the outer rotor is evenly spaced with memory permanent magnets along the circumferential direction.

Further, the stator core is made of silicon steel sheets laminated along the axial direction of the outer rotor.

Furthermore, the outer wall of the stator core has a cogging-free structure, and the armature winding is connected to the outer surface of the stator core by pouring epoxy resin to achieve a physical connection between the armature winding and the stator core.

Furthermore, the outer wall of the stator core has a cogging structure, and the armature winding is embedded in the cogging of the outer wall of the stator core to achieve physical connection between the armature winding and the stator core.

Further, the armature winding is a three-phase AC winding, and the armature winding adopts a delta or star connection.

Further, the DC magnetizing winding is a concentrated winding.

Further, one side of the inner surface of the outer rotor is provided with first rotor teeth and first rotor slots evenly spaced along the circumferential direction, and the other side of the inner surface of the outer rotor is provided with second rotor teeth and second rotor teeth evenly spaced along the circumferential direction. Rotor slots, the memory permanent magnets are respectively arranged in the first rotor slot and the second rotor slot.

Further, the memory permanent magnet has the same axial length as the first rotor slot and the second rotor slot.

Further, the tooth axes of the first rotor teeth and the second rotor teeth are spatially different by 0 or 180 electrical degrees.

Furthermore, when the motor is under rated load, the memory permanent magnet is in a fully magnetized state; when the motor needs to perform field weakening and speed expansion, the DC magnetizing winding generates a DC pulse magnetic field in the opposite direction to the memory permanent magnet magnetic field to realize the permanent magnet magnetic field. flexible adjustment.

The principle and effect of this program are:

The present invention replaces the rare earth permanent magnets of the traditional alternating pole permanent magnet synchronous motor with memory permanent magnets, and the combination of the memory permanent magnets and the DC excitation winding can adjust the motor excitation magnetic field in real time. Under rated load conditions, the memory permanent magnet is fully magnetized and does not affect the system output performance. In the field weakening state, the DC magnetizing winding is controlled to generate a DC pulse magnetic field to adjust the magnetization of the memory permanent magnet, thereby increasing the motor speed range and broadening the motor's efficient operating range.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 shows an overall schematic structural diagram of an external rotor variable flux alternating pole permanent magnet synchronous motor proposed by an embodiment of the present application;

Figure 2 shows an exploded schematic structural diagram of an external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application;

Figure 3 shows a schematic diagram of the stator core with a cogging structure in an external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application;

Figure 4 shows a schematic diagram of the stator core without cogging structure in an external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application;

Figure 5 shows the front view and cross-sectional view of an external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application, wherein (a) is an external rotor variable flux alternating pole permanent magnet synchronous motor The front view, (b) is a cross-sectional view of the A-A section of an external rotor variable flux alternating pole permanent magnet synchronous motor;

Figure 6 shows a schematic assembly diagram of the rotor and memory permanent magnets in an external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application;

Figure 7 shows a schematic structural diagram of the rotor in an external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application;

Figure 8 shows a schematic diagram of the radial excitation magnetic circuit generated by the memory permanent magnet when the external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application is under load operation;

Figure 9 shows a schematic diagram of the axial excitation magnetic circuit generated by the memory permanent magnet when the external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application is in a load operating state;

Figure 10 shows the axial excitation magnetic circuit generated by the memory permanent magnet and the DC excitation winding generated when the external rotor variable flux alternating pole permanent magnet synchronous motor proposed by the embodiment of the present application is in the load state and transitions to the weak field state. Schematic diagram of the axial magnetic circuit.

Detailed ways

In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined inventive purpose, the specific implementation manner, structure, features and effects of the present invention are described in detail below with reference to the drawings and preferred embodiments.

The reference signs in the drawings of the description include: stator yoke 1, stator core 2, first stator core 2-1, second stator core 2-2, memory permanent magnet 3, first memory permanent magnet 3 -1. Second memory permanent magnet 3-2, outer rotor 4, first rotor teeth 4-11, first rotor slots 4-12, second rotor teeth 4-21, second rotor slots 4-22, armature Winding 5, DC excitation winding 6, radial magnetic circuit 7, axial magnetic circuit 8, DC excitation winding excitation circuit 9.

An external rotor variable flux alternating pole permanent magnet synchronous motor, the embodiment of which is shown in Figures 1 and 2, includes an inner stator and an outer rotor 4, and the overall performance is an inner stator-outer rotor 4 topology, as follows:

The inner stator includes a stator yoke 1, a stator core 2, an armature winding 5 and a DC magnetizing winding 6. The stator yoke 1 is located in the stator core 2. There are two stator cores 2 and two stator irons. The core 2 has exactly the same material properties and structural dimensions. To facilitate understanding by those skilled in the art, the core 2 is named the first stator core 2-1 and the second stator core 2-2 respectively; the first stator core 2-1 and the second stator core 2-2 are both made of silicon steel sheets laminated along the axial direction of the outer rotor 4. As shown in Figure 3, the first stator core 2-1 and the second stator core 2 -2 are all cogging structures. Of course, the structures of the first stator core 2-1 and the second stator core 2-2 of the present invention are not limited to this. As shown in Figure 4, the first stator core 2 The surface of -1 and the second stator core 2-2 can also have a cogging structure; the armature winding 5 is a three-phase double-layer distributed short-distance AC winding, using a Y-shaped connection method, and other AC winding forms can also be used; DC regulation Magnetic winding 6 is a concentrated winding.

As shown in Figure 5, the stator yoke 1, the first stator core 2-1, the second stator core 2-2, the DC magnetizing winding 6, the armature winding 5, the memory permanent magnet 3 and the outer rotor 4 are the same. Shaft assembly. Furthermore, the outer diameter of the stator yoke 1 is equal to the inner diameters of the first stator core 2-1 and the second stator core 2-2. The armature winding 5 is embedded in the outer wall or the slot of the outer wall of the first stator core 2-1 and the second stator core 2-2. When the outer wall of the stator core 2 has a cogging structure, the armature winding 5 The physical connection between the armature winding 5 and the stator core 2 is realized by pouring epoxy resin on the outer surface of the stator core 2; when the outer wall of the stator core 2 has a cogging structure, the armature winding 5 is embedded in into the slots on the outer wall of the stator core 2 to realize the physical connection between the armature winding 5 and the stator core 2 .

As shown in Figures 6 and 7, the outer rotor 4 has tooth groove structures evenly distributed on both sides of the inner surface, so that the outer rotor 4 includes first rotor teeth 4-11, first rotor slots 4-12, and second rotor teeth. Structural features of teeth 4-21 and second rotor slots 4-22, wherein first rotor teeth 4-11 and first rotor slots 4-12 are alternately arranged along the circumference, second rotor teeth 4-21 and second rotor The slots 4-22 are alternately arranged along the circumference, and the axis of the first rotor tooth 4-11 and the axis of the second rotor tooth 4-21 differ by 0 or 180 electrical degrees to improve the energy storage density of the permanent magnet motor. There are two memory permanent magnets 3 and the two memory permanent magnets 3 have exactly the same material properties and structural dimensions. To facilitate the understanding of those skilled in the art, they are named the first memory permanent magnet 3-1 and the second memory permanent magnet respectively. The magnet 3-2 and the memory permanent magnet 3 have a tile structure. The first memory permanent magnet 3-1 is adhesively connected to the first rotor slot 4-12, and the second memory permanent magnet 3-2 is connected to the second rotor slot 4. -22 adopts adhesive connection. The outer rotor 4 is forged from a single piece of steel with good magnetic permeability. The outer rotor 4 has an integrated structure, which increases the strength of the outer rotor 4 to meet the demand for higher speeds.

As shown in Figures 8 and 9, when the motor is under rated load, there is no current flowing inside the DC excitation winding 6, and the memory permanent magnet 3 is in a fully magnetized state. The radial magnetic circuit 7 produced by the memory permanent magnet 3 is shown in FIG. 8 , and the axial magnetic circuit 8 produced by the memory permanent magnet 3 is shown in FIG. 10 . Among them, the radial magnetic circuit 7 is the working magnetic circuit of the motor, and the axial magnetic circuit 8 is the leakage magnetic circuit.

As shown in Figure 10, during the transition of the motor from the load state to the weakened field state, the DC pulse magnetic field in the opposite direction to the memory permanent magnet magnetic field is generated by the DC magnetizing winding 6 to adjust the air gap magnetic field. The excitation magnetic circuit 9 of the DC magnetizing winding 6 generated by the DC magnetizing winding 6 is shown in Figure 10 , and the axial magnetic circuit 8 generated by the memory permanent magnet 3 is shown in Figure 10 . The DC magnetizing magnetic field adjusts the permanent magnet magnetic field to achieve the purpose of weakening the permanent magnet magnetic field.

By changing the structure of the traditional alternating pole permanent magnet motor and adopting an outer rotor-inner stator topology, the present invention increases the strength of the rotor and improves the speed range. In addition, after replacing the rare earth permanent magnets of the traditional alternating pole permanent magnet motor with the memory permanent magnet 3, the combination of the memory permanent magnet 3 and the DC excitation winding 6 can adjust the motor excitation magnetic field in real time. Under rated load conditions, the memory permanent magnet 3 is fully magnetized and does not affect the system output performance. In the weakened field state, the DC magnetizing winding 6 is controlled to generate a DC pulse magnetic field to adjust the magnetization of the memory permanent magnet 3, thereby increasing the high-efficiency operating range of the motor.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above in preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art , without departing from the scope of the technical solution of the present invention, the technical contents disclosed above can be used to make some changes or modifications to equivalent embodiments with equivalent changes. However, without departing from the technical solution of the present invention, according to the technical solution of the present invention, In essence, any brief modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims (6)

1. An external rotor variable flux alternating pole permanent magnet synchronous motor, characterized in that it includes an inner stator and an outer rotor: The inner stator includes a symmetrically arranged stator core, an armature winding provided on the stator core, a stator yoke provided within the stator core, and a DC magnetizing winding provided between the two stator cores; The outer rotor is located outside the inner stator, and the inner surface of the outer rotor is provided with memory permanent magnets evenly spaced along the circumferential direction; one side of the inner surface of the outer rotor is provided with first rotor teeth and first rotor teeth evenly spaced along the circumferential direction. Rotor slots, the other side of the inner surface of the outer rotor is provided with second rotor teeth and second rotor slots evenly spaced along the circumferential direction, the axis of the first rotor tooth and the axis of the second rotor tooth differ by 0 or 180 electrical degrees, so The memory permanent magnets are respectively provided in the first rotor slot and the second rotor slot; When the motor is under rated load, the memory permanent magnet is in a fully magnetized state; when the motor needs to be driven in a wide speed range or to generate electricity at constant voltage, the DC magnetizing winding generates a DC pulse magnetic field in the opposite direction to the memory permanent magnet magnetic field, thereby allowing flexible adjustment. Memory of the magnetic field strength generated by the permanent magnet. 2. An outer rotor variable flux alternating pole permanent magnet synchronous motor according to claim 1, characterized in that the stator core is made of silicon steel sheets laminated along the axial direction of the outer rotor. 3. An external rotor variable flux alternating pole permanent magnet synchronous motor according to claim 1 or 2, characterized in that the outer wall of the stator core has a cogging-free structure, and the armature winding is formed by pouring epoxy resin. Connected to the outer surface of the stator core to achieve physical connection between the armature winding and the stator core. 4. An external rotor variable flux alternating pole permanent magnet synchronous motor according to claim 1 or 2, characterized in that the outer wall of the stator core has a cogging structure, and the armature winding is embedded in the stator core. in the slots on the outer wall to realize the physical connection between the armature winding and the stator core. 5. An external rotor variable flux alternating pole permanent magnet synchronous motor according to claim 4, characterized in that the DC magnetizing winding is a concentrated winding. 6. An external rotor variable flux alternating pole permanent magnet synchronous motor according to claim 1, characterized in that the memory permanent magnet has the same axial direction as the first rotor slot and the second rotor slot. length.