Asymmetric consequent pole rotor

Abstract

The present invention relates to a rotor and, more particularly, to an asymmetric consequent pole rotor for reducing cogging torque and torque ripple. The asymmetric consequent pole rotor of the present invention is an asymmetric consequent pole-type rotor in which permanent magnets and iron cores other than the permanent magnets are alternately arranged in a circumferential direction, and the permanent magnets are provided to be wider than the iron cores, that is, provided to have a high pole-arc ratio, thereby minimizing a reduction in no-load counter electromotive force, and determining,through FEA analysis, the pole-arc ratio of the permanent magnets and the iron cores as points exhibiting reduction of magnet usage and minimizing reduction in no-load counter electromotive force, thus maximizing efficiency and performance.

Description

Asymmetric Consequent Pole Rotor

[0001] The present invention relates to a rotor, and more specifically, to an asymmetric consequent pole rotor that minimizes the reduction of no-load back EMF while maximally reducing the amount of permanent magnets used.

[0002] The present invention is the result of the research project "2024 Export-Oriented 'Tech-Bridge' of the SME Technology Innovation Development Project" conducted with funding from the government (Korea Institute of Technology Information Promotion Agency for SMEs) and support from the Korea Institute of Technology Information Promotion Agency for SMEs (No.RS-2024-00470254).

[0003]

[0004] The need for permanent magnet motors is on the rise because they can deliver higher efficiency and power density compared to conventional motors. These permanent magnet motors can be applied to automotive applications (vacuum pumps, EPS, EV and HEV drives, electric compressors, ISGs, etc.) and home appliances (washing machine drives, refrigerator compressors, air conditioner compressors, air conditioner fans, electric fan fans, etc.).

[0005] In addition, as illustrated in FIG. 1, the permanent magnet motor may include a rotor (1), a permanent magnet (2) inserted into the rotor, and a stator slot (3) provided on the outer surface of the permanent magnet (2). It has been pointed out that the main problems of the permanent magnet motor are cogging torque, which is generated by the attractive force between the permanent magnet (2) of the rotor (1) and the stator slot (3), and torque ripple, which causes the output torque to periodically increase or decrease as the rotor (1) rotates. Cogging torque and torque ripple were the main causes of vibration and noise during motor operation, and since this affects the overall performance of the motor, it was necessary to reduce them.

[0006] Accordingly, slotless motors and slotless consequent pole type motors have been developed. However, conventional consequent pole rotors had a problem in that they could not satisfy the output targeted by the application because the magnetic flux of the permanent magnets was reduced. More specifically, conventional consequent pole rotors had a limit in increasing the polarity of one permanent magnet, making it difficult to satisfy the reduced no-load back EMF achieved by increasing the amount of magnets used.

[0007] [Prior Art Literature]

[0008] [Patent Literature]

[0009] Republic of Korea Registered Patent No. 10-2242638 “Rotor for Maximizing Air Gap Magnetic Flux of a Slotless Motor and Slotless Motor Including the Same”

[0010]

[0011] The present invention has been devised to solve the above-mentioned problems, and the objective of the present invention is to provide an asymmetric consequent pole type rotor capable of minimizing the reduction of no-load back EMF by providing a rotor in which permanent magnets and non-permanent magnet iron cores are alternately arranged in the circumferential direction, wherein the permanent magnets are provided wider than the iron cores, that is, provided to have a high polarity ratio.

[0012] Furthermore, the invention provides an asymmetric consequent pole rotor that maximizes efficiency and performance by determining, through FEA analysis, the polarity ratio of the permanent magnet and iron core to the point that minimizes magnet usage reduction and the drop in no-load back EMF.

[0013]

[0014] In order to solve the problem described above, an asymmetric consequent pole rotor according to one embodiment of the present invention is formed in a cylindrical shape with a hole formed in the center and includes a rotor core that rotates along a predetermined central axis, and a magnetic force generating part provided along the circumferential direction on the outer surface of the rotor core and generating magnetic force, wherein the magnetic force generating part includes two or more permanent magnets and an iron core that is inserted between the permanent magnets and has no polarity, and the area provided with the permanent magnets is wider than the area provided with the iron core.

[0015] In addition, the permanent magnet is formed in an arc shape having a predetermined first central angle with respect to the central axis of the rotor core, and the iron core is disposed between the permanent magnets and is characterized by being formed in an arc shape having a predetermined second central angle with respect to the central axis of the rotor core.

[0016] In addition, the first central angle and the second central angle are characterized by being formed such that the asymmetric consequent pole constant, which is the ratio of the amount of permanent magnet usage to the amount of no-load back EMF reduction compared to the case where the permanent magnet and the iron core are provided in equal proportions, has a maximum value.

[0017] In addition, the first central angle is characterized by being 1.12 to 1.36 times larger than the second central angle.

[0018] In addition, each permanent magnet is characterized by having the same polarity.

[0019] In addition, the iron core is characterized by being formed integrally with the rotor core.

[0020] In addition, one surface of the permanent magnet and one surface of the iron core are formed to face each other, and one surface of the permanent magnet is formed to tilt toward the iron core as it extends radially outward, and one surface of the iron core is formed to tilt toward the permanent magnet as it extends radially outward.

[0021] In addition, the rotor core is characterized by having an insertion groove formed concavely on its outer surface into which a permanent magnet is inserted.

[0022]

[0023] The asymmetric consequent pole rotor of the present invention, configured as described above, has the effect of minimizing the reduction of no-load back electromotive force by providing an asymmetric consequent pole type rotor in which permanent magnets and non-permanent magnet iron cores are alternately arranged in the circumferential direction, and the permanent magnets are provided wider than the iron cores, i.e., provided to have a high polarity ratio.

[0024] In addition, through FEA analysis, the polarity ratio of the permanent magnet and iron core is determined to the point that minimizes magnet usage reduction and the drop in no-load back EMF, thereby maximizing efficiency and performance.

[0025]

[0026] Figure 1 is a schematic diagram illustrating a conventional permanent magnet motor.

[0027] FIG. 2 is an overall perspective view of the asymmetric consequent pole rotor of the present invention.

[0028] FIG. 3 is a partial cross-sectional view of the asymmetric consequent pole rotor of the present invention.

[0029] Figure 4 is a graph showing the change in the asymmetric consequent pole constant according to the polarity of the permanent magnet of the present invention.

[0030] FIG. 5 is a graph showing the change in no-load back EMF according to the rotation angle of the asymmetric consequent pole rotor of the present invention in the case where the permanent magnet is formed asymmetrically and in the case where it is formed symmetrically, respectively.

[0031]

[0032] Hereinafter, the technical concept of the present invention will be explained in more detail using the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical concept of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0033]

[0034] Below, the basic configuration of the asymmetric consequent pole rotor (1000) of the present invention will be described with reference to FIG. 2.

[0035] The asymmetric consequent pole rotor (1000) of the present invention may include a rotor core (100) and a magnetic force generating unit (200). More specifically, the rotor core (100) is formed in a cylindrical shape with a hole formed in the center and can rotate along a predetermined central axis, and the magnetic force generating unit (200) is provided along the circumferential direction on the outer surface of the rotor core (100) and can generate magnetic force. At this time, the magnetic force generating unit (200) includes two or more permanent magnets (210) and an iron core (220) that is inserted between the permanent magnets (210) and has no polarity, and the area where the permanent magnets (210) are provided may be wider than the area where the iron core (220) is provided. More clearly, the polarity of the permanent magnets (210) may be higher than that of the iron core (220). By forming the magnetic force generating part (200) in this way, the size of the permanent magnet (210) can be increased compared to a case in which the permanent magnet (210) and the iron core (220) are symmetrically provided, thereby minimizing the reduction of the no-load back electromotive force.

[0036] At this time, each permanent magnet (210) may have the same polarity, for example, it may be the N pole. Also, each permanent magnet (210) may all have the same size and the same shape. Accordingly, a magnetic field can be generated uniformly when the rotor rotates.

[0037] Additionally, the iron core (220) can be formed integrally with the rotor core (100), can be made of the same material as the rotor core (100), and can be manufactured together with the rotor core (100). Accordingly, the asymmetric consequent pole rotor (1000) of the present invention can be produced simply by assembling the permanent magnet (210) to the rotor core (100), and furthermore, the manufacturing efficiency of the asymmetric consequent pole rotor (1000) can be increased.

[0038]

[0039] Hereinafter, the magnetic force generating unit (200) of the present invention will be described in more detail with reference to FIGS. 3 to 5.

[0040] As shown in FIG. 3, the permanent magnet (210) has a predetermined first central angle with respect to the central axis of the rotor core (100). It can be formed in an arc shape having. In addition, the iron core (220) is disposed between the permanent magnets (210), and a predetermined second central angle with respect to the central axis of the rotor core (100). It can be formed into an arc shape having. At this time, the first central angle Task 2 central angle It can be formed to have a predetermined extreme ratio. The extreme ratio to be described below is the ratio of the first central angle to the second central angle. / This means that as the polarity rate increases to 1 or more, the size of the permanent magnet (210) becomes larger than the iron core (220).

[0041] The first central angle in more detail Task 2 central angle The extreme success rate of is the asymmetric consistent pole constant explained in Equation 1 below. It can be formed to have a maximum value. : (Amount of reduction in the use of permanent magnet (210) compared to the case where the permanent magnet (210) and the iron core (220) are provided in equal proportions) / (Amount of reduction in no-load back EMF compared to the case where the permanent magnet (210) and the iron core (220) are provided in equal proportions))

[0042] Formula 1 :

[0043]

[0044] Referring to the graph in Fig. 4 derived through finite element analysis (FEA) to limit the range of the aforementioned extreme efficiency, the asymmetric consequent pole constant It generally appears to increase as the extreme acceptance rate increases, but shows a phenomenon of decreasing again starting from a specific point (where the extreme acceptance rate is 1.24). That is, the asymmetric consistent pole constant at the point where the extreme acceptance rate is 1.24 It can be seen that it has a maximum value, and the efficiency of the asymmetric consequent pole rotator (1000) is also at its maximum. Accordingly, the most desirable extreme efficiency may be 1.12 to 1.36 (a range of approximately 10 percent from the point where the asymmetric consequent pole constant is at its maximum). That is, the first central angle is the second central angle It can be 1.12 to 1.36 times larger than that.

[0045] In this way, the first central angle and the second central angle By forming them differently, as shown in FIG. 5, it was confirmed that the no-load back EMF of the asymmetric consequent pole rotor (1000) of the present invention, which has an extreme efficiency of 1 or more as indicated by the dotted line, is measured to be higher than that of the conventional case, which has an extreme efficiency of 1 as indicated by the solid line.

[0046] Additionally, as shown in FIG. 3, one side of the permanent magnet (210) and one side of the iron core (220) are formed to face each other, and one side of the permanent magnet (210) is formed to tilt toward the iron core (220) as it extends radially outward, and one side of the iron core (220) is formed to tilt toward the permanent magnet (210) as it extends radially outward. Accordingly, manufacturing convenience can be increased. In addition, the rotor core (100) may have an insertion groove (110) formed concavely on its outer surface into which the permanent magnet (210) is inserted, and accordingly, the bonding strength between the rotor core (100) and the permanent magnet (210) can be increased.

[0047]

[0048] The technical concept of the present invention should not be interpreted as being limited to the above-described embodiments. Not only is the scope of application diverse, but various modifications are possible at the level of a person skilled in the art without departing from the essence of the invention claimed in the claims. Accordingly, such improvements and modifications fall within the scope of protection of the present invention insofar as they are obvious to a person skilled in the art.

[0049] [Explanation of the symbol]

[0050] 1000 : Asymmetric Consequent Pole Rotor

[0051] 100: Rotor core

[0052] 110 : Insertion slot

[0053] 200 : Magnetic force generating unit

[0054] 210 : Permanent magnet

[0055] 220 : Iron core

[0056] S: Stator

Claims

1. A rotor core formed in a cylindrical shape with a hole formed in the center and rotating along a predetermined central axis; A magnetic force generating part provided along the circumferential direction on the outer surface of the rotor core and generating magnetic force; is included. The above magnetic force generating unit is, It includes two or more permanent magnets and an iron core that is inserted between the permanent magnets and has no polarity, and An asymmetric consequent pole rotor characterized in that the region equipped with the permanent magnet is wider than the region equipped with the iron core.

2. In Paragraph 1, The above permanent magnet is, It is formed in an arc shape having a predetermined first central angle with respect to the central axis of the rotor core, and The above iron core is, An asymmetric consequent pole rotor characterized by being disposed between the above permanent magnets and formed in an arc shape having a predetermined second central angle with respect to the central axis of the rotor core.

3. In Paragraph 2, The above first central angle and the above second central angle are, Regarding the amount by which the no-load back EMF is reduced compared to the case where the above permanent magnet and the above iron core are provided in the same ratio An asymmetric consequent pole rotor characterized by being formed such that an asymmetric consequent pole constant, which is the ratio of the amount of permanent magnet usage that decreases compared to the case where the above permanent magnet and the above iron core are provided in equal proportions, has a maximum value.

4. In Paragraph 2, The above first central angle is, An asymmetric consequent pole rotator characterized by being 1.12 to 1.36 times larger than the second central angle mentioned above.

5. In Paragraph 1, An asymmetric consequent pole rotor characterized in that each of the above-mentioned permanent magnets has the same polarity.

6. In Paragraph 5, An asymmetric consequent pole rotor characterized in that the iron core is formed integrally with the rotor core.

7. In Paragraph 2, One side of the above permanent magnet and one side of the above iron core are formed to face each other, and One surface of the above permanent magnet is formed to tilt toward the iron core as it extends radially outward, and An asymmetric consequent pole rotor characterized in that one surface of the iron core is formed to tilt toward the permanent magnet side as it extends radially outward.

8. In Paragraph 1, The above rotor core is, An asymmetric consequent pole rotor having a recessed insertion groove formed on the outer surface into which the above-mentioned permanent magnet is inserted.

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