WO2021120680A1

WO2021120680A1 - Motor rotor and alternating-pole motor

Info

Publication number: WO2021120680A1
Application number: PCT/CN2020/111625
Authority: WO
Inventors: 李权锋; 桂鹏千; 史进飞; 丁佳婷; 马晓皓
Original assignee: 珠海格力电器股份有限公司
Priority date: 2019-12-16
Filing date: 2020-08-27
Publication date: 2021-06-24
Also published as: CN110994839B; CN110994839A

Abstract

Provided are a motor rotor and an alternating-pole motor; said motor rotor comprises a rotor core (1); the rotor core (1) comprises a first permanent magnet pole (2), a second permanent magnet pole (3), a first alternating pole (4), and a second alternating pole (5); the first permanent magnet pole (2) and the second permanent magnet pole (3) are adjacent, forming a set of permanent magnet poles; the polarities of the first permanent magnet pole (2) and the second permanent magnet pole (3) are opposite; the first alternating pole (4) and the second alternating pole (5) are adjacent, forming a set of alternating poles; the set of permanent magnet poles and the set of alternating poles are alternately arranged along the circumferential direction of the motor rotor. The motor rotor can reduce the difficulty of control, reduce motor torque ripple, and improve motor performance.

Description

Motor rotor and alternating pole motor

The present disclosure claims the priority of a Chinese patent application filed with the Chinese Patent Office on December 16, 2019, with an application number of 201911295317.1 and an invention title of "Motor Rotor and Alternating Pole Motor", the entire content of which is incorporated into the present disclosure by reference.

Technical field

The present disclosure relates to the technical field of electrical equipment, in particular to a motor rotor and an alternating-pole motor.

Background technique

The number of permanent magnets used in alternating-pole permanent magnet synchronous motors is only half of the number of permanent magnets in traditional permanent magnet synchronous motors. Therefore, the permanent magnets are more fully utilized, which can significantly reduce the amount of permanent magnets used, thereby reducing the cost of the motor.

In the existing alternating-pole permanent magnet motor, when the axis of one group of U-phase winding is aligned with the permanent magnet, the axis of the other two groups of U-phase winding is also aligned with the permanent magnet, and the V-phase or W-phase winding is now aligned with the permanent magnet. It can only face the alternating poles, that is, the iron core poles. The three-phase winding magnetic circuit is asymmetrical, which causes the control difficulty to increase, the motor torque fluctuation increases, and the motor performance decreases.

Summary of the invention

Therefore, the technical problem to be solved by the present disclosure is to provide a motor rotor and an alternating-pole motor, which can reduce control difficulty, reduce motor torque fluctuations, and improve motor performance.

In order to solve the above problems, the present disclosure provides a motor rotor, including a rotor core, the rotor core includes a first permanent magnetic pole, a second permanent magnetic pole, a first alternating pole and a second alternating pole, the first permanent magnetic pole and the second permanent magnetic pole The magnetic poles are adjacent to form a set of permanent magnetic pole groups. The first and second permanent magnetic poles have opposite polarities. The first and second alternating poles are adjacent to form a set of alternating pole groups. The permanent magnetic pole groups and the alternating pole groups are adjacent to each other. The circumferential direction of the motor rotor is alternately arranged.

In some embodiments, a first air groove is provided at the location where the first alternating pole and the second alternating pole meet.

In some embodiments, the first air slot extends along the circumferential direction of the rotor core.

In some embodiments, in a section perpendicular to the central axis of the rotor core, the angle formed by the line connecting the two end points of the radially outer side of the first air groove with the center of the rotor core is a1, A first installation slot is provided on a permanent magnet pole, a second installation slot is provided on the second permanent magnet pole, a first permanent magnet is provided in the first installation slot, and a second permanent magnet is provided in the second installation slot. The angle formed by the line connecting the radially outer end points of the adjacent sides of the magnet and the second permanent magnet with the center of the rotor core is ar, 1≤a1/ar≤3.

In some embodiments, the first permanent magnet pole is provided with a first installation groove, the second permanent magnet pole is provided with a second installation groove, the first installation groove is provided with a first permanent magnet, and the second installation groove is provided with a second installation groove. Two permanent magnets, in a section perpendicular to the central axis of the rotor core, the angle formed by the line connecting the two end points of the radially outer side of the first permanent magnet and the center of the rotor core is am, and the second permanent magnet The angle formed by the connection between the two end points of the radially outer side of the magnet and the center of the rotor core is an, the first air slot is close to the radially outer end point of the second permanent magnet and the second permanent magnet is close to the first air The angle formed by the line connecting the radially outer end point of the slot and the center of the rotor core is a1m, where 0.8≤a1m/am≤1.1 and 0.8≤a1m/an≤1.1.

In some embodiments, the radial thickness of the first air groove is t1, the radial thickness of the first permanent magnet is tm, and the radial thickness of the second permanent magnet is tn, where 1.2≤t1/tm≤2.5.

In some embodiments, a second air slot is further provided on the rotor core, and the second air slot is provided on the radially inner circumferential side of the first air slot and extends radially toward the center of the rotor core. The air groove communicates with the first air groove.

In some embodiments, a third air slot is further provided on the rotor core, and the third air slot is connected to the radially inner circumferential side of the second air slot and extends on both sides of the rotor core in the circumferential direction, adjacent to each other. A bridge is formed between the third air grooves.

In some embodiments, in a cross-section perpendicular to the central axis of the rotor core, the side extension line of the bridge portion and the radially inner side of the first permanent magnet form an intersection, and the intersection is the dividing point, the first permanent magnet The ratio of the circumferential length on the side of the intersection away from the bridging portion to the total circumferential length of the first permanent magnet is 0.67 to 0.9; the side extension of the bridging portion forms an intersection with the radially inner side of the second permanent magnet, Taking the intersection as the boundary point, the ratio of the circumferential length of the second permanent magnet on the side of the intersection away from the bridge to the total circumferential length of the second permanent magnet is 0.67-0.9.

According to another aspect of the present disclosure, there is provided an alternating-pole motor including a motor rotor and a motor stator, and the motor rotor is the above-mentioned motor rotor.

In some embodiments, the motor stator includes a stator iron core, stator iron cores are provided with stator teeth, and three-phase evenly distributed coil windings are wound on the stator teeth.

The motor rotor provided by the present disclosure includes a rotor core. The rotor core includes a first permanent magnetic pole, a second permanent magnetic pole, a first alternating pole, and a second alternating pole. The first permanent magnetic pole and the second permanent magnetic pole are adjacent to each other to form a set Permanent magnet pole group, the polarity of the first permanent magnet pole and the second permanent magnet pole are opposite, the first alternating pole and the second alternating pole are adjacent to form a set of alternating pole group, the permanent magnet pole group and the alternating pole group alternate along the circumferential direction of the motor rotor Set up. In the motor rotor of the present disclosure, the distribution structure of the permanent magnetic poles and the alternating poles is changed, so that the permanent magnetic poles and the alternating poles are alternately arranged in a group along the circumferential direction, and the polarities of the two permanent magnetic poles in a group are opposite, which can make the three The phase winding magnetic circuit is symmetrical, which effectively reduces the difficulty of control, reduces the torque fluctuation of the motor, and improves the performance of the motor.

Description of the drawings

FIG. 1 is a schematic diagram of the structure of a motor rotor of the first embodiment of the disclosure;

2 is a schematic diagram of the structure of the motor rotor of the second embodiment of the disclosure;

3 is a schematic diagram of the structure of the motor rotor of the third embodiment of the disclosure;

4 is a schematic diagram of the armature magnetic force line impedance of the motor rotor of the embodiment of the disclosure;

Fig. 5 is a graph showing the influence of a1/ar of a motor rotor on torque ripple according to an embodiment of the disclosure;

FIG. 6 is a comparison diagram of current waveforms between the rotor of the electric motor and related technologies according to an embodiment of the disclosure

FIG. 7 is a comparison diagram of torque curves between the motor rotor of the embodiments of the disclosure and related technologies.

The reference signs are indicated as:

1. The rotor core; 2. The first permanent magnetic pole; 3. The second permanent magnetic pole; 4. The first alternating pole; 5. The second alternating pole; 6. The first air slot; 7. The first mounting slot; 8. The second installation slot; 9, the first permanent magnet; 10, the second permanent magnet; 11, the second air slot; 12, the third air slot; 13, the bridge portion; 14, the stator core; 15, the stator tooth; 16 , Coil winding.

Detailed ways

With reference to Figures 1 to 7, according to an embodiment of the present disclosure, the motor rotor includes a rotor core 1, and the rotor core 1 includes a first permanent magnetic pole 2, a second permanent magnetic pole 3, a first alternating pole 4, and a second Alternating pole 5, the first permanent magnetic pole 2 and the second permanent magnetic pole 3 are adjacent to form a set of permanent magnetic poles, the first permanent magnetic pole 2 and the second permanent magnetic pole 3 are opposite in polarity, the first alternating pole 4 and the second alternating pole 5 are adjacent to each other to form a set of alternating pole groups. The permanent magnet pole groups and the alternating pole groups are alternately arranged along the circumference of the motor rotor.

In the motor rotor of the present disclosure, the distribution structure of the permanent magnetic poles and the alternating poles is changed, so that the permanent magnetic poles and the alternating poles are alternately arranged in a group along the circumferential direction, and the polarities of the two permanent magnetic poles in a group are opposite, which can make The three-phase winding magnetic circuit is symmetrical, which effectively reduces the difficulty of control, reduces the torque fluctuation of the motor, and improves the performance of the motor.

In some embodiments, the first air groove 6 is provided at the location where the first alternating pole 4 and the second alternating pole 5 meet.

In this disclosure, the installation relationship of permanent magnets is changed, and the installation relationship of permanent magnets is optimized, forming a permanent magnet installation relationship of permanent magnet pole-permanent magnet pole-alternating pole-alternating pole, which is significantly different from the traditional method, so the traditional alternate The optimization strategy of the pole motor is no longer applicable to the optimization of the alternating pole motor of the present disclosure. In the solution of the present disclosure, not only the coordination between adjacent permanent magnetic poles and alternating poles needs to be optimized, but also the relationship between adjacent permanent magnetic poles-permanent magnetic poles and alternating poles-alternating poles and their respective combinations need to be optimized. Therefore, in the present disclosure, the first air slot 6 is provided between the adjacent alternating poles, which can adjust the matching of the adjacent alternating poles, so that the distribution of the magnetic field lines is more uniform, and the torque fluctuation is reduced; the alternating poles can be adjusted to the adjacent alternating poles. The permanent magnet pole-permanent magnet pole relationship makes the permanent magnet pole alternate pole more symmetrical overall and reduces the torque fluctuation. It can also adjust the adjacent permanent magnet pole-alternate pole coordination to reduce the torque fluctuation.

In this embodiment, the first permanent magnet pole 2 is provided with a first installation groove 7, the second permanent magnet pole 3 is provided with a second installation groove 8, the first installation groove 7 is provided with a first permanent magnet 9, and the second permanent magnet A second permanent magnet 10 is provided in the installation groove 8. The above-mentioned permanent magnet is made of neodymium iron boron material, for example.

In some embodiments, the first air groove 6 extends along the circumferential direction of the rotor core 1. In this embodiment, the first air groove 6 is, for example, a fan ring segment.

In a section perpendicular to the central axis of the rotor core 1, the angle formed by the line connecting the two end points of the radially outer side of the first air slot 6 and the center of the rotor core 1 is a1, and the first permanent magnet The angle formed by the line connecting the radially outer ends of the adjacent sides of 9 and the second permanent magnet 10 with the center of the rotor core 1 is ar, 1≤a1/ar≤3.

The first air slot 6 is located between two alternating poles of opposite polarity, which is where they demarcate. ar represents the size of the boundary between the two permanent magnets. The ratio of the two determines the ratio of the permanent magnet pole to the alternating pole. If the ratio is too small, the distance between the alternating poles is large, and the ratio is too small, and the distance between the permanent magnet poles is too large. It will cause the asymmetry between the permanent magnetic pole and the alternating pole, and due to the particularity of the alternating pole, the two are not designed to be equal. Research shows that a1/ar=1～3 have the best effect, as shown in Figure 5.

In a section perpendicular to the central axis of the rotor core 1, the angle formed by the line connecting the two end points of the radially outer side of the first permanent magnet 9 and the center of the rotor core 1 is am, and the second permanent magnet The angle formed by the line connecting the two end points of the radially outer side of 10 and the center of the rotor core 1 is an, and the first air slot 6 is close to the radially outer end point of the second permanent magnet 10 and the second permanent magnet 10 The included angle formed by the line connecting the radially outer end point of the first air slot 6 and the center of the rotor core 1 is a1m, where 0.8≤a1m/am≤1.1 and 0.8≤a1m/an≤1.1. The ratio characterizes the width ratio of the adjacent permanent magnet poles to the alternating poles. Within the ratio range, the torque ripple of the motor can be minimized.

The radial thickness of the first air groove 6 is t1, the radial thickness of the first permanent magnet 9 is tm, and the radial thickness of the second permanent magnet 10 is tn, where 1.2≤t1/tm≤2.5. Although there are no permanent magnets on the alternating poles, considering that the air gaps facing the two are the same, this is the main source of magnetic resistance. In order to make the two more symmetrical, the thickness of the first air slot 6 can be used to make the alternating poles There is a magnetic resistance equivalent to that of the permanent magnetic poles. At the same time, in order to ensure the division effect of the first air slot 6 on the adjacent alternating poles, it is best to set the ratio in the range.

The rotor core 1 is also provided with a second air slot 11, the second air slot 11 is provided on the radially inner circumferential side of the first air slot 6, and extends in the radial direction toward the center of the rotor core 1. The second air slot 11 The tank 11 communicates with the first air tank 6. Since the magnetic field lines of the permanent magnet always start from the N pole to the S pole, when the permanent magnet installation slots that are far away are not too far apart, there will be a leakage magnetic circuit 1 as shown in FIG. 2, causing a decrease in torque. Providing the second air groove 11 with eyes in the radial direction can cut off the leakage magnetic circuit 1 and greatly increase the output torque of the motor. The second air groove 11 has a decreasing width along the direction away from the first air groove 6 to form a trapezoidal groove structure. At a place far away from the first air groove 6, the width of the second air groove 11 has less influence on the air gap magnetic density, so its width is reduced to improve the mechanical strength.

The rotor core 1 is also provided with a third air slot 12, the third air slot 12 is connected to the radially inner circumferential side of the second air slot 11, and extends along the circumferential direction of the rotor core 1 on both sides, adjacent A bridge 13 is formed between the third air grooves 12. In order to enhance the role of the air slots in guiding the magnetic lines of force, a third air slot 12 extending in the circumferential direction is provided on the radially inner peripheral side of the second air slots 11, which can better constrain the direction of the magnetic lines of force, as shown in Figures 2 and As shown in Fig. 3, when the magnetic field lines are emitted from the N-pole permanent magnet surface of the first permanent magnet 9 shown, the magnetic field lines of about the left half are from the N pole to the S surface of the adjacent permanent magnet on the left, and the magnetic field lines of the right half are about It extends from the N pole to the rotor yoke, and then extends radially outward to the adjacent alternating poles, forming an S pole. The second air slot 11 can shorten the length of the part of the magnetic field lines extending to the rotor yoke. The long magnetic circuit will cause the reduction of the utilization rate of the magnetic field lines, and guide the magnetic field lines to the iron core pole on the right side better and faster. At the same time, the alternating pole motor has the problem of magnetic flux leakage in the rotating shaft, that is, a part of the magnetic field lines emitted by the permanent magnet will enter the rotating shaft of the motor, as shown in the magnetic flux leakage circuit 2. By arranging the third air slot 12 along the circumferential direction, the magnetic field lines entering the motor shaft can be obstructed, and the magnetic field lines entering the motor shaft can be reduced, thereby reducing the magnetic flux leakage problem of the shaft and improving the operating efficiency of the motor.

In a cross section perpendicular to the central axis of the rotor core 1, the side extension line of the bridge 13 and the radially inner side of the first permanent magnet 9 form an intersection. The intersection is the dividing point, and the first permanent magnet 9 is located at the intersection. The ratio of the circumferential length of the side away from the bridging portion 13 to the total circumferential length of the first permanent magnet 9 is 0.67 to 0.9; the side extension of the bridging portion 13 and the radially inner side of the second permanent magnet 10 form The intersection point, taking the intersection point as the demarcation point, the ratio of the circumferential length of the second permanent magnet 10 on the side of the intersection away from the bridging portion 13 to the total circumferential length of the second permanent magnet 10 is 0.67-0.9.

The magnetic field lines adjusted by the third air slot 12 are mainly the magnetic field lines emitted from the right half of the N pole face of the first permanent magnet in Figure 3, so that it can better enter the adjacent iron core pole, so the third air slot 12 mainly shields It is the magnetic field lines of the right half of the permanent magnet it faces. If the range of intersection A is less than 0.67 of the total circumferential length of the first permanent magnet 9, the right half of the permanent magnet cannot be effectively covered. If the position of the intersection A is greater than 0.9 of the total circumferential length of the first permanent magnet 9, The third air slot 12 will not only cover the right half, but also the left half, because the left half is equivalent to two permanent magnets connected in series to generate magnetic lines of force. The magnetic density is relatively strong. If more shielded, magnetic saturation is likely to occur. , Cause the torque to drop, and the size of the bridge 13 will be limited, and the mechanical strength will drop. The arrangement relationship between the third air groove 12 and the second permanent magnet 10 is the same as the arrangement relationship between the third air groove 12 and the first permanent magnet 9 and will not be described in detail here.

According to an embodiment of the present disclosure, an alternating-pole motor includes a motor rotor and a motor stator, and the motor rotor is the above-mentioned motor rotor.

In some embodiments, the motor stator includes a stator iron core 14 with stator teeth 15 provided on the stator iron core 14, and three-phase evenly distributed coil windings 16 are wound on the stator teeth 15.

In this embodiment, the alternating-pole motor is an 18-slot 12-pole motor, and each of the three-phase windings has 6 coils. When U1 faces the permanent magnetic poles, U2 faces the alternating poles, U3 faces the permanent magnetic poles, and U4 faces the alternating poles. U5 faces the permanent magnetic poles, U6 faces the alternating poles, and the V phase is the same as W. The schematic diagram of the winding magnetic circuit is shown in Figure 1 and Figure 4. R permanent magnetic pole represents permanent magnetic pole reluctance, R alternate pole represents alternating pole reluctance , It is not difficult to see that the magnetic resistance of the three-wire winding magnetic circuit is completely symmetrical, and the control difficulty is significantly reduced.

The current waveform of the motor adopting the motor rotor of the embodiment of the present disclosure is as shown in Fig. 6. It can be clearly seen from the figure that the control current of the motor of the embodiment of the present disclosure has a smaller harmonic content, and the torque curve is compared with, for example, As shown in FIG. 7, the motor of the embodiment of the present disclosure has smaller torque ripple.

It is easy for those skilled in the art to understand that, on the premise that there is no conflict, the above advantageous methods can be freely combined and superimposed.

The above are only the preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Any modification, equivalent replacement and improvement made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure. Inside. The above are only the preferred embodiments of the present disclosure. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principles of the present disclosure, several improvements and modifications can be made, and these improvements and modifications should also be made. It is regarded as the protection scope of this disclosure.

Claims

A motor rotor, comprising a rotor iron core (1), the rotor iron core (1) comprising a first permanent magnetic pole (2), a second permanent magnetic pole (3), a first alternating pole (4) and a second alternating pole (5), the first permanent magnetic pole (2) and the second permanent magnetic pole (3) are adjacent to form a set of permanent magnetic poles, the first permanent magnetic pole (2) and the second permanent magnetic pole (3) ) Is opposite in polarity, the first alternating pole (4) and the second alternating pole (5) are adjacent to form a set of alternating pole groups, and the permanent magnet pole group and the alternating pole group are along the motor rotor The circumferential direction is alternately set.
The motor rotor according to claim 1, wherein a first air slot (6) is provided at the contact position of the first alternating pole (4) and the second alternating pole (5).
The motor rotor according to claim 2, wherein the first air slot (6) extends along the circumferential direction of the rotor core (1).
The motor rotor according to claim 3, wherein, in a section perpendicular to the central axis of the rotor core (1), the two end points of the radially outer side of the first air slot (6) and The included angle formed by the central line of the rotor core (1) is a1, the first permanent magnetic pole (2) is provided with a first mounting slot (7), and the second permanent magnetic pole (3) is provided with a first mounting slot (7). A second installation groove (8) is provided, a first permanent magnet (9) is provided in the first installation groove (7), and a second permanent magnet (10) is provided in the second installation groove (8), The angle formed by the line connecting the radially outer ends of the adjacent sides of the first permanent magnet (9) and the second permanent magnet (10) with the center of the rotor core (1) is ar, 1≤ a1/ar≤3.
The motor rotor according to claim 3, wherein a first mounting slot (7) is provided on the first permanent magnetic pole (2), and a second mounting slot (8) is provided on the second permanent magnetic pole (3). ), a first permanent magnet (9) is provided in the first installation slot (7), and a second permanent magnet (10) is provided in the second installation slot (8), which is perpendicular to the rotor core In the section of the central axis of (1), the angle formed by the line connecting the two end points of the radially outer side of the first permanent magnet (9) and the center of the rotor core (1) is am, The included angle formed by the line connecting the two end points of the radially outer side of the second permanent magnet (10) and the center of the rotor core (1) is an, and the first air slot (6) is close to The radially outer end point of the second permanent magnet (10) and the radially outer end point of the second permanent magnet (10) close to the first air slot (6) are formed by connecting the line with the center of the rotor core (1) The included angle is a1m, where 0.8≤a1m/am≤1.1, 0.8≤a1m/an≤1.1.
The motor rotor according to claim 2, wherein the radial thickness of the first air slot (6) is t1, the radial thickness of the first permanent magnet (9) is tm, and the second permanent magnet The radial thickness of (10) is tn, where 1.2≤t1/tm≤2.5.
The motor rotor according to any one of claims 2 to 6, wherein a second air slot (11) is further provided on the rotor core (1), and the second air slot (11) is provided in the rotor core (1). The first air groove (6) is on the radially inner circumferential side and extends in the radial direction toward the center of the rotor core (1), and the second air groove (11) is connected to the first air groove ( 6) Connectivity.
The motor rotor according to claim 7, wherein a third air slot (12) is further provided on the rotor core (1), and the third air slot (12) is connected to the second air slot ( 11) radially inner peripheral side, and extend along the circumferential direction of the rotor core (1) to both sides, and a bridge portion (13) is formed between the adjacent third air grooves (12).
The motor rotor according to claim 8, wherein, in a section perpendicular to the central axis of the rotor core (1), the side extension line of the bridge portion (13) and the first permanent magnet ( The radially inner side of 9) forms a point of intersection, and taking the point of intersection as the demarcation point, the circumferential length of the first permanent magnet (9) on the side of the intersection away from the bridge portion (13) accounts for the The ratio of the total circumferential length of the first permanent magnet (9) is 0.67-0.9; the side extension of the bridge portion (13) forms an intersection with the radially inner side of the second permanent magnet (10), Taking the intersection as the demarcation point, the circumferential length of the second permanent magnet (10) located on the side of the intersection away from the bridging portion (13) accounts for the total circumferential length of the second permanent magnet (10) The length ratio is 0.67 to 0.9.
An alternating-pole motor, comprising a motor rotor and a motor stator, and the motor rotor is the motor rotor according to any one of claims 1 to 9.
The alternating-pole motor according to claim 10, wherein the motor stator comprises a stator core (14), the stator core (14) is provided with stator teeth (15), and the stator teeth (15) are Three-phase evenly distributed coil windings (16) are wound.