CN103929026A - permanent magnet motor - Google Patents

Abstract

The invention provides a permanent magnet motor. The permanent magnet motor includes: an inner rotor including an inner rotor iron core; a stator arranged around the inner rotor and having a gap with the inner rotor, and the stator includes a plurality of stators arranged at intervals in the circumferential direction The stator core with slots and multiple teeth and the stator winding placed in the stator slots; the outer rotor, the outer rotor is coaxially arranged with the inner rotor and rotates at the same speed at the same speed, the outer rotor is arranged around the stator and has a gap with the stator , the inner rotor core is provided with a plurality of first magnetic pole slots arranged side by side along the radial direction of the inner rotor. The invention effectively solves the problems of large motor drive current and low motor efficiency of the permanent magnet motor in the prior art.

Description

permanent magnet motor

technical field

The invention specifically relates to a permanent magnet motor.

Background technique

Compared with traditional motors, dual-rotor permanent magnet motors have the advantages of small axis size, high power density, large torque/mass ratio, and stable low-speed operation, and have been widely used. However, the permanent magnets of permanent magnet motors in the prior art are mostly The surface-mounted structure is adopted, that is, the permanent magnets are arranged on the surface of the rotor facing the stator, but the permanent magnet motor in the prior art does not increase the utilization of the reluctance torque, resulting in a large motor drive current and low motor efficiency.

Contents of the invention

The present invention aims to provide a permanent magnet motor to solve the problems of high motor drive current and low motor efficiency of the permanent magnet motor in the prior art.

In order to achieve the above object, the present invention provides a permanent magnet motor, comprising: an inner rotor, including an inner rotor iron core; a stator, arranged around the inner rotor and having a gap with the inner rotor, and the stator includes multiple A stator core with a stator slot and multiple teeth and a stator winding placed in the stator slot; an outer rotor, the outer rotor and the inner rotor are coaxially arranged and rotate at the same speed at the same direction, and the outer rotor is arranged around the stator and between the stator and the stator With gaps, the inner rotor core is provided with a plurality of first magnetic pole slots arranged side by side along the radial direction of the inner rotor.

Further, the outer rotor includes an outer rotor iron core, the inner surface of the outer rotor iron core is provided with a second permanent magnet, and the included angle between the first magnetic pole centerline of the inner rotor and the corresponding second magnetic pole centerline of the outer rotor is between 20° and 45°.

Further, the outer rotor includes an outer rotor iron core, and the outer rotor iron core is provided with multiple layers of second magnetic pole slots distributed along the radial direction of the outer rotor at intervals, and multiple sets of second magnetic pole units are arranged on the outer rotor iron core, each The set of second magnetic pole units includes second permanent magnets respectively arranged in the second magnetic pole slots. The axially superimposed magnetic force lines of multiple second permanent magnets in each set of second magnetic pole units point to the same direction to form magnetic poles N or S. The inner rotor There is a first included angle between the first magnetic pole centerline of the corresponding outer rotor and the second magnetic pole centerline of the corresponding outer rotor.

Further, multiple sets of first magnetic pole units are arranged on the inner rotor core, and each set of first magnetic pole units includes multiple first permanent magnets, and the multiple first permanent magnets are respectively arranged in different first magnetic pole slots. The axially superimposed magnetic force lines of the first permanent magnets of the first magnetic pole unit are aligned to form a magnetic pole N or S, and the outer rotor is arranged opposite to the inner rotor with the same magnetic pole.

Further, the stator core has an annular structure, the stator slots include first slots and second slots, the teeth include first teeth and second teeth, and the first slots and first teeth are arranged at intervals along the circumferential direction of the stator on the stator core. On the inner wall, the second slots and the second teeth are arranged at intervals along the circumferential direction of the stator on the outer wall of the stator core, and there is a first tooth between the center line of the first tooth and the center line of the second tooth adjacent to the first tooth. Two included angles.

Further, the quantity ratio of the first grooves to the second grooves is 1:2.

Further, the interior of the inner rotor iron core is provided with a plurality of magnetic flux blocking parts, and the plurality of magnetic flux blocking parts are respectively arranged in the first magnetic pole slots, the magnetic flux blocking parts are the magnetic isolation medium, and the inner rotor iron core is the magnetic conduction medium .

Further, the magnetic flux blocking portion corresponds to the outer rotor magnetic pole, and a third angle is formed between the center line of the magnetic flux blocking portion and the second magnetic pole center line of the corresponding outer rotor magnetic pole.

Further, the third included angle is between 40° and 50°.

Furthermore, the stator core is composed of a plurality of stator blocks sequentially snapped together, the splicing gap between the multiple stator blocks is located in the middle of the teeth of the stator, and a gap is formed between the first teeth and the second teeth on both sides of the stator core. Iron core yoke, each stator block is located at the iron core yoke for winding.

Applying the technical solution of the present invention, the permanent magnet motor includes: an inner rotor, including an inner rotor core; a stator, which is arranged around the inner rotor and has a gap with the inner rotor, and the stator includes a plurality of stator slots and a plurality of A stator core with three teeth and a stator winding placed in the stator slot; the outer rotor, the outer rotor and the inner rotor are coaxially arranged and rotate at the same speed in the same direction, the outer rotor is arranged around the stator and has a gap with the stator, and the inner rotor The iron core is provided with a plurality of first magnetic pole slots arranged in parallel along the radial direction of the inner rotor. The inner rotor has a multi-layer first magnetic pole slot structure and is distributed with the same polarity in the same tangential direction. The magnetic poles N and S of the inner rotor are alternately distributed. Since multiple first magnetic pole slots are arranged side by side along the radial direction of the inner rotor, the inner rotor The asymmetrical magnetic circuit of the rotor produces reluctance torque, and the increase in the utilization of reluctance torque is beneficial to reduce the driving current of the motor, reduce the loss of the motor, and improve the overall efficiency of the motor.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 shows the structural representation of the first embodiment of the permanent magnet motor of the present invention;

Fig. 2 shows the structural representation of the inner rotor of the permanent magnet motor of Fig. 1;

Fig. 3 shows the distribution diagram of the magnetic pole center line of the permanent magnet motor of Fig. 1;

Fig. 4 shows the structural representation of the stator of the permanent magnet motor of Fig. 1;

Fig. 5 shows a schematic diagram of the distribution of tooth centerlines of the stator of Fig. 4;

Fig. 6 shows a schematic structural view of the stator block of Fig. 4;

Fig. 7 shows the schematic structural diagram of the outer rotor of the permanent magnet motor of the second embodiment of the present invention;

Fig. 8 shows the distribution diagram of the magnetic pole centerlines of the inner and outer rotors of the permanent magnet motor of Fig. 7;

Fig. 9 shows the structural schematic diagram of the inner rotor of the third embodiment of the permanent magnet motor of the present invention;

Fig. 10 shows a schematic diagram of the distribution of the centerline of the magnetic poles of the outer rotor of the permanent magnet motor of Fig. 9 and the centerline of the magnetic flux blocking part of the inner rotor;

Fig. 11 shows the comparative schematic diagram of the driving current of the permanent magnet motor of the first embodiment and the prior art;

Fig. 12 shows a schematic diagram of the influence of the α angle on the synthetic electromagnetic torque of the motor in the first embodiment of the permanent magnet motor;

Fig. 13 shows a schematic diagram of the influence of the β angle on the synthetic electromagnetic torque of the motor in the third embodiment of the permanent magnet motor;

Fig. 14 shows a schematic diagram of the influence of the γ angle on the cogging torque of the motor in the first embodiment of the permanent magnet motor;

Fig. 15 is a schematic diagram showing the influence of the θ angle on the cogging torque of the motor in the second embodiment of the permanent magnet motor.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and examples.

The present invention provides the first embodiment of the permanent magnet motor, referring to Fig. 1 and Fig. 2, the permanent magnet motor of this embodiment comprises the inner rotor 10, the stator 20 and the outer rotor 30, the inner rotor 10 comprises the inner rotor iron core 11, the stator 20 is arranged around the inner rotor 10 and has a gap with the inner rotor 10. The stator 20 includes a stator core 21 with a plurality of stator slots 22 and a plurality of teeth 23 spaced apart in the circumferential direction and a stator winding 24 placed in the slots. The outer rotor 30 is arranged coaxially with the inner rotor 10 and rotates in the same direction at the same speed. The outer rotor 30 is arranged around the stator 20 and has a gap with the stator 20. The inner rotor core 11 is arranged in parallel along the radial direction of the inner rotor 10. A plurality of first magnetic pole slots 13 are provided.

The inner rotor 10 has a structure of multi-layer first magnetic pole slots 13 and is distributed with the same polarity in the same tangential direction. The magnetic poles forming the inner rotor are shown in Figure 2, and the magnetic poles N and S are alternately distributed. The radial juxtaposition of the inner rotor 10 causes the magnetic circuit of the inner rotor to be asymmetrical, resulting in an unequal inductance between the d-axis and the q-axis, resulting in a reluctance torque. The increase in the utilization of the reluctance torque is conducive to reducing the drive current of the motor and reducing the inductance of the motor. Loss, improve the overall efficiency of the motor. Fig. 11 illustrates the comparison between the permanent magnet motor A of the prior art and the permanent magnet motor B of the present embodiment under the same output torque situation, and the magnitude of the motor drive current. It can be clearly seen from Fig. 11 that the permanent magnet motor of the present embodiment The motor drive current of the magnetic motor is smaller than that of the prior art under the condition of the same output torque.

As shown in Figures 1 and 3, the outer rotor 30 in this embodiment includes an outer rotor core 31, the inner surface of the outer rotor core 31 is provided with second permanent magnets 32 with magnetic poles N and S alternately distributed, and the inner rotor The angle α between the first magnetic pole centerline 14 of 10 and the corresponding second magnetic pole centerline 34 of the outer rotor is between 20° and 45°, and the magnetic pole centerline of the outer rotor is ahead of the inner rotor magnetic pole in the direction of rotor rotation center line. It should be noted that all angles involved in this application are electrical angles, electrical angle = mechanical angle X number of motor pole pairs, and electrical angle is equal to mechanical angle multiplied by number of motor pole pairs.

Figure 12 illustrates the influence of the outer rotor magnetic pole centerline forming an α angle with the inner rotor magnetic pole centerline in the direction of rotor rotation on the combined electromagnetic torque of the motor. It can be seen from the figure that the magnetic pole centerlines of the inner and outer rotors are staggered by a certain angle It can make the motor obtain greater synthetic electromagnetic torque under the same current, and when the magnetic pole centerline of the outer rotor leads the inner rotor by an angle of 20° to 45° in the direction of rotor rotation, that is, the included angle α is 20° to 45° Between, under the same current, the effective value of the combined electromagnetic torque of the motor is the largest.

The inner rotor core is provided with multiple sets of first magnetic pole units, each set of first magnetic pole units includes multiple first permanent magnets 12, and multiple first permanent magnets 12 are respectively arranged in different first magnetic pole slots 13, each set The axially superimposed magnetic force lines of the first permanent magnets 12 of the first magnetic pole unit are aligned to form a magnetic pole N or S, and the outer rotor 30 is opposite to the inner rotor 10 with the same N or S polarity. By arranging the inner and outer rotors with the same polarity relative to each other, the motor can generate a larger torque under the same current than the opposite arrangement with different polarities, thereby reducing the winding loss of the motor and increasing the efficiency of the motor.

As shown in Figure 4 and Figure 5, the stator core 21 is an annular structure, the stator slot 22 includes a first slot 221 and a second slot 222, the teeth 23 include a first tooth 231 and a second tooth 232, the first slot 221 and the second slot One tooth 231 is arranged at intervals on the inner wall of the stator core 21 along the circumferential direction of the stator, the second slot 222 and the second tooth 232 are arranged at intervals on the outer wall of the stator iron core 21 along the circumferential direction of the stator, and the center of the first tooth 231 There is a second included angle γ between the line and the center line of the second tooth 232 adjacent to the first tooth 231 . In the manufacturing process, the first teeth and the second teeth are formed by cutting the first slots 221 and the second slots 222 on the stator core 21, and the first teeth and the first slots are arranged adjacent to each other at intervals, so that the second The two teeth are adjacent to the second groove and arranged at intervals. Figure 14 shows the influence of the included angle between the first tooth centerline and the second tooth centerline of the stator on the cogging torque ripple of the motor. It can be seen from Figure 14 that the motor in the prior art with γ' being 0 The fluctuation amplitude of the motor cogging torque, and the fluctuation amplitude of the motor cogging torque decreases with the existence of the γ angle. Within the adjustable range of the second included angle γ, there is an optimal included angle γ1 to make the cogging torque The torque ripple reaches the minimum value, and the optimal angle γ1 changes with the change of the matching value of the motor slot and pole.

The quantity ratio of the first grooves 221 to the second grooves 222 is 1:2. Since the outer wall of the stator has a larger space than the inner wall, setting more slots on the outer wall can effectively reduce the cogging torque ripple of the outer rotor.

The stator core 21 is composed of a plurality of stator blocks sequentially clamped. The splicing gap between the multiple stator blocks is located in the middle of the teeth of the stator, and an iron gap is formed between the first teeth and the second teeth on both sides of the stator core 21. Core yoke, where each stator segment is wound at the core yoke. The stator core 21 is composed of a plurality of stator blocks 111 sequentially snapped together. The yoke of the stator core is formed between the first tooth and the second tooth on both sides of the stator core 21. The stator core adopts a splicing structure, and the splicing gap is located in the middle of the teeth of the stator. wire, each stator block is located at the yoke for winding, as shown in Figure 6, the stator core is formed by splicing stator blocks 111 into a ring, and the shape of the stator block is determined according to the specific shape of the stator core, and A buckle structure is provided on the yoke of the stator core, so that the stator core can be sequentially buckled together. By adopting the above method, the effective utilization rate of the electromagnetic steel plate material of the motor can be effectively improved, the winding speed of the stator can be increased, and the production time can be reduced.

The present invention also provides the second embodiment of the permanent magnet motor, specifically referring to Fig. 7 and Fig. 8, the permanent magnet motor of this embodiment includes an inner rotor, a stator and an outer rotor 30, the structure and connection of the permanent magnet motor of this embodiment The relationship is basically the same as that of the permanent magnet motor of the first embodiment, and the only difference is that the outer rotor core 31 is provided with multiple layers of second magnetic pole slots 33 spaced along the radial direction of the outer rotor 30. The outer rotor core 31 Multiple sets of second magnetic pole units are arranged on the top, each set of second magnetic pole units includes second permanent magnets 32 respectively arranged in different second magnetic pole slots 33, and a plurality of second permanent magnets 32 in each set of second magnetic pole units The axially superimposed magnetic lines of force point to the same direction to form the magnetic pole N or S, and there is a first angle θ between the first magnetic pole centerline 14 of the inner rotor 10 and the corresponding second magnetic pole centerline 34 of the outer rotor. Both the outer rotor and the inner rotor in this embodiment adopt the structure of multi-layer permanent magnets, the inner rotor and the outer rotor are coaxially arranged, and the inner rotor magnetic poles opposite to the second teeth of the stator have the same polarity as the outer rotor magnetic poles.

Figure 15 shows a schematic diagram of the influence of the angle between the inner and outer rotor pole centerlines on the cogging torque ripple of the motor. It can be seen from Figure 15 that the motor cogging torque of the motor in the prior art where θ' is 0 degrees Fluctuation amplitude, the motor cogging torque fluctuation amplitude decreases with the existence of the angle θ of the center line of the magnetic pole. Within the adjustable range of the angle θ, there is an optimal angle θ1 to minimize the cogging torque ripple. The optimal angle θ1 changes with the change of the matching value of the motor slot and pole. The technical effect of the permanent magnet motor of the second embodiment is basically the same as that of the permanent magnet motor of the first embodiment.

The present invention also provides a third embodiment of the permanent magnet motor, specifically referring to Fig. 9 and shown in Fig. 10, the permanent magnet motor of this embodiment includes an inner rotor 10, a stator and an outer rotor 30, the permanent magnet motor of this embodiment The structure and connection relationship are basically the same as those of the permanent magnet motor of the first embodiment, and the only difference is that a plurality of magnetic flux blocking parts 15 are arranged inside the inner rotor core 11, and the plurality of magnetic flux blocking parts 15 are respectively arranged on the first In the magnetic pole slot 13, the magnetic flux blocking part 15 is a magnetic isolation medium, and the inner rotor iron core is a magnetic conduction medium.

The inner rotor 10 has a multi-layer magnetic flux blocking part structure, and the magnetic flux blocking part is air or other non-magnetic medium. When the stator winding is energized, the magnetic force lines of the magnetic field mainly flow in or out from the inner rotor core, resulting in the magnetic flux blocking part of the inner rotor It is asymmetrical with the magnetic circuit of the inner rotor core, generates reluctance torque, and rotates synchronously with the outer rotor; the surface of the permanent magnet of the outer rotor 30 in this embodiment is glued to the inner surface of the outer rotor iron core.

The magnetic flux blocking portion 15 corresponds to the outer rotor magnetic pole, and there is a third angle β between the centerline of the magnetic flux blocking portion 15 and the second magnetic pole centerline 34 of the corresponding outer rotor magnetic pole, as can be seen in FIG. 13 , The magnetic pole centerline of the outer rotor is ahead of the flux blocking part centerline of the inner rotor in the rotor rotation direction, and when the magnetic pole centerline of the outer rotor forms an angle β between the rotor rotating direction and the flux blocking part centerline of the inner rotor, β An angle other than 0 can make the motor obtain greater electromagnetic torque under the same current. And it can be seen from Figure 13 that when β is at an angle of 40° to 50°, the effective value of the combined electromagnetic torque of the motor is the largest.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A permanent magnet motor, comprising: Inner rotor (10), including inner rotor core (11); The stator (20) is arranged around the inner rotor (10) and has a gap with the inner rotor (10). The stator (20) includes a plurality of stator slots (22) and a plurality of A stator core (21) with teeth (23) and a stator winding (24) placed in the stator slot (22); An outer rotor (30), the outer rotor (30) is arranged coaxially with the inner rotor (10) and rotates at the same speed and in the same direction, the outer rotor (30) is arranged around the stator (20) and is connected with the inner rotor (10) There are gaps between the stators (20), It is characterized in that the inner rotor iron core (11) is provided with a plurality of first magnetic pole slots (13) arranged side by side along the radial direction of the inner rotor (10). 2. The permanent magnet motor according to claim 1, characterized in that, the outer rotor (30) includes an outer rotor core (31), and the inner surface of the outer rotor core (31) is provided with a second For permanent magnets (32), the included angle between the first magnetic pole centerline (14) of the inner rotor (10) and the corresponding second magnetic pole centerline (34) of the outer rotor (30) is between 20° and between 45°. 3. The permanent magnet motor according to claim 1, characterized in that, the outer rotor (30) includes an outer rotor core (31), and the outer rotor core (31) is internally provided with (30) has multiple layers of second magnetic pole slots (33) distributed at intervals in the radial direction, the outer rotor core (31) is provided with multiple sets of second magnetic pole units, and each set of second magnetic pole units includes a set of In the second permanent magnet (32) in the second magnetic pole slot (33), the axially superimposed magnetic force lines of the plurality of second permanent magnets (32) in each group of the second magnetic pole units are aligned to form together For the magnetic pole N or S, there is a first angle (θ) between the first magnetic pole centerline (14) of the inner rotor (10) and the corresponding second magnetic pole centerline (34) of the outer rotor. 4. The permanent magnet motor according to claim 1, characterized in that, the inner rotor core (11) is provided with multiple sets of first magnetic pole units, and each set of first magnetic pole units includes multiple first permanent magnet pole units. A magnet (12), a plurality of the first permanent magnets (12) are respectively arranged in different first magnetic pole slots (13), and the axis of the first permanent magnets (12) of each group of the first magnetic pole units The superimposed magnetic force lines point to the same direction to form a magnetic pole N or S, and the outer rotor (30) is arranged opposite to the inner rotor (10) with the same magnetic pole. 5. The permanent magnet motor according to claim 1, characterized in that, the stator core (21) is an annular structure, and the stator slot (22) includes a first slot (221) and a second slot (222) , the teeth (23) include first teeth (231) and second teeth (232), the first slots (221) and the first teeth (231) are arranged at intervals along the circumferential direction of the stator On the inner wall of the stator core (21), the second slots (222) and second teeth (232) are arranged at intervals along the circumferential direction of the stator (20) on the outer wall of the stator core (21) , there is a second included angle (γ) between the centerline of the first tooth (231) and the centerline of the second tooth (232) adjacent to and corresponding to the first tooth (231). 6. The permanent magnet motor according to claim 5, characterized in that the quantity ratio of the first slots (221) to the second slots (222) is 1:2. 7. The permanent magnet motor according to claim 1, characterized in that a plurality of magnetic flux blocking parts (15) are arranged inside the inner rotor core (11), and a plurality of magnetic flux blocking parts (15) ) are respectively arranged in the first magnetic pole slots (13), the magnetic flux blocking part (15) is a magnetic isolation medium, and the inner rotor core (11) is a magnetic conduction medium. 8. The permanent magnet motor according to claim 7, characterized in that, the magnetic flux blocking part (15) corresponds to the magnetic pole of the outer rotor, and the center line of the magnetic flux blocking part (15) is in line with the phase There is a third included angle (β) between the second magnetic pole centerlines (34) of the corresponding outer rotor magnetic poles. 9. The permanent magnet motor according to claim 8, characterized in that, the third included angle (β) is between 40° and 50°. 10. The permanent magnet motor according to claim 5, characterized in that, the stator core (21) is composed of a plurality of stator blocks connected sequentially, and the splicing gaps between the plurality of stator blocks are located at the In the middle of the teeth (23) of the stator, an iron core yoke is formed between the first teeth and the second teeth on both sides of the stator core (21), and each stator block is located at the Winding at the yoke of the iron core.