Magnetic gear with changeable gear ratio

Abstract

The present disclosure relates to a magnetic gear comprising: a stator formed in a fixed state and having a first magnetomotive force formed when electricity flows through a provided coil; a first rotor formed to be rotatable outside the stator; and a second rotor formed to be rotatable outside the first rotor and having a second magnetomotive force formed by a provided permanent magnet, wherein the first rotor may be configured such that a magnetic body and a non-magnetic body are alternately formed, and each of the magnetic bodies may include at least one notch structure.

Description

Technology Field

[0001] The present disclosure relates to a magnetic gear, and more specifically to a magnetic gear capable of changing the gear ratio. Background Technology

[0003] Mechanical gears transmit power through mechanical contact as the primary and secondary sides mesh with each other. This causes wear and mechanical failure due to friction, so lubricants are used to prevent them.

[0004] As a solution to these drawbacks, magnetic gears operating through the interaction of permanent magnets are being proposed in various fields, such as automotive systems, wind turbines, and low- and high-speed equipment. Since magnetic gears have no physical contact, there is no wear or damage to contact interfaces caused by friction; they also have the advantage of being free from lubrication and maintenance. Furthermore, magnetic gears, being non-physical, are characterized by very low noise and vibration.

[0005] However, there is a disadvantage that the configuration of the magnetic gear becomes complex and the size increases because new configurations or mechanisms must be added to vary the gear ratio of the magnetic gear. In addition, there is a problem in that continuously changing gear ratios cannot be implemented because the number of pole pieces must also change according to the change in the number of poles.

[0006] Therefore, recently, various gear ratio conversion technologies are being researched to increase efficiency in high-speed ranges, and attempts to implement gear ratio conversion through electronic control are continuing. The problem to be solved

[0008] The present disclosure aims to provide a magnetic gear capable of changing the gear ratio without changing the physical configuration. means of solving the problem

[0010] A magnetic gear according to an aspect of one embodiment of the present disclosure comprises: a stator formed in a fixed state and having a first magnetic force formed when electricity flows through a provided coil; a first rotor formed to be rotatable outside the stator; and a second rotor formed to be rotatable outside the first rotor and having a second magnetic force formed by a provided magnet, wherein the first rotor may be configured such that a magnetic body and a non-magnetic body are alternately formed, and each of the magnetic bodies may include at least one notch structure.

[0011] According to one embodiment, the at least one notch structure may be formed on either the outer or inner side of the magnetic body.

[0012] According to one embodiment, the total number of magnetic bodies included in the first rotor can be determined based on a predetermined gear ratio.

[0013] According to one embodiment, the number of magnetic bodies can be identified as changed in the magnetic gear based on a change in the number of pole pairs of the stator.

[0014] According to one embodiment, the number of magnetic bodies is identified differently in the magnetic gear depending on whether the notch is applied, which is determined based on the change in the number of pole pairs of the fixed magnet, and the number of magnetic bodies identified in the magnetic gear when the notch is applied may be greater than the number of magnetic bodies identified in the magnetic gear when the notch is not applied.

[0015] According to one embodiment, when the notch is applied, the number of magnetic bodies identified in the magnetic gear can increase in proportion to the number of notches included in one magnetic body.

[0016] According to one embodiment, the gear ratio of the magnetic gear can be determined based on a change in the number of pole pairs of the stator.

[0017] According to one embodiment, the speed of the first rotor may be slower than the speed of the second rotor.

[0018] According to one embodiment, the gear ratio of the magnetic gear can be increased in proportion to the number of magnetic bodies.

[0019] In a magnetic gear according to an aspect of another embodiment of the present disclosure, the gear comprises: a stator formed in a fixed state and having a first magnetic force formed when electricity flows through a provided coil; a first rotor formed to be rotatable inside the stator; and a second rotor formed to be rotatable inside the first rotor and having a second magnetic force formed by a provided magnet, wherein the first rotor may be configured such that a magnetic body and a non-magnetic body are alternately formed, and each of the magnetic bodies may include at least one notch structure. Effects of the invention

[0021] According to the present disclosure, the gear ratio of a magnetic gear can be changed without structural changes.

[0022] According to the present disclosure, since the gear ratio is converted using an electromagnet instead of a permanent magnet, it may be advantageous for cost reduction. Brief explanation of the drawing

[0024] A brief description of each drawing is provided to help to better understand the drawings cited in the detailed description of the present disclosure. FIG. 1 is a diagram showing the configuration of a magnetic gear according to one embodiment of the present disclosure. FIG. 2 is a cross-sectional view of a magnetic gear including a notched pole piece according to one embodiment of the present invention. FIG. 3 illustrates the principle of operation for changing the gear ratio of a magnetic gear according to one embodiment of the present disclosure. FIG. 4 relates to a method for inducing a change in the number of pole pieces of a magnetic gear by adjusting the number of pairs of poles according to one embodiment of the present disclosure. FIGS. 5A and 5B illustrate a mode for inducing a gear ratio of a magnetic gear by adjusting the number of inner / outer poles according to one embodiment of the present disclosure. FIG. 6 shows a cross-sectional view of an internal magnetic gear according to one embodiment of the present disclosure. FIG. 7 is a cross-sectional view of a structure of pole pieces with notches formed therein included in a first rotor according to one embodiment of the present disclosure. FIG. 8 is a flowchart illustrating a method for generating and controlling a magnetic gear according to one embodiment of the present disclosure. Specific details for implementing the invention

[0025] The technical concept of the present disclosure is subject to various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the technical concept of the present disclosure to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the scope of the technical concept of the present disclosure.

[0026] In describing the technical concept of the present disclosure, detailed descriptions of related prior art are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the technical concept of the present disclosure. Furthermore, numbers used in the description of the present invention (e.g., First, Second, etc.) are merely identification symbols to distinguish one component from another.

[0027] In addition, when a component is described in this document as being "connected" or "joined" with another component, it should be understood that the component may be directly connected or joined to the other component, but unless otherwise specifically stated, it may also be connected or joined through another component in between.

[0028] Additionally, terms such as “~part,” “~device,” and “~part” described herein refer to a unit that processes at least one function or operation, and this may be implemented as hardware such as a processor, microprocessor, microcontroller, CPU (Central Processing Unit), GPU (Graphics Processing Unit), APU (Accelerate Processor Unit), DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), software, or a combination of hardware and software.

[0029] Furthermore, it is intended to clarify that the classification of the components in this document is merely based on the primary function each component is responsible for. That is, two or more components described below may be combined into a single component, or a single component may be divided into two or more components based on more subdivided functions. Additionally, each component described below may additionally perform some or all of the functions of other components in addition to its own primary function, and it goes without saying that some of the primary functions of each component may be exclusively performed by other components.

[0030] Hereinafter, various embodiments according to the technical concept of the present disclosure will be described in detail in turn.

[0032] FIG. 1 is a diagram showing the configuration of a magnetic gear according to one embodiment of the present disclosure.

[0033] To clarify the understanding of the present disclosure, the operating principle of the magnetic gear is briefly explained.

[0034] Referring to FIG. 1, the magnetic gear generally has a structure in which a pole piece (110), which is a piece of iron core between the permanent magnets of the inner rotor and the outer rotor, is present, and torque can be generated as the magnetic flux created by the inner rotor (105) and / or the outer rotor (115) passes through the pole piece (110).

[0035] For example, the 14th-order (sinus wave repeated 14 times) harmonic magnetic flux generated by the 28-pole permanent magnets of the outer rotor passes through 16 pole pieces (Assuming that magnetic flux passes through the iron core and not the air due to the difference in magnetic resistance between the iron core and the air) Then, it is modulated into the second harmonic and magnetically coupled with the second harmonic generated by the 4-pole permanent magnet of the inner rotor, thereby generating torque. Furthermore, the second harmonic generated by the 4-pole permanent magnet of the inner rotor also passes through the pole piece and is modulated into the 14th harmonic, and torque can be generated when the modulated 14th harmonic is magnetically coupled with the 14th harmonic generated by the 28-pole permanent magnet of the outer rotor. At this time, the number of pole pieces and the gear ratio of the magnetic gear (As a concept encompassing both reduction ratio and torque ratio, the ratio of the speed of the outer rotor to the speed of the inner rotor) It can be determined by the number of inner and outer poles of the permanent magnet.

[0036] The magnetomotive force generated by the permanent magnets of the inner rotor and / or the outer rotor can be expressed as a periodic waveform as the N and S poles are spatially repeated, as shown at the bottom of FIG. 1 (a waveform in which the sin wave is repeated as many times as the number of pole pairs). Therefore, the magnetomotive force generated by the permanent magnets of the inner rotor can be expressed as a Fourier series as follows:

[0037] [Mathematical Formula 1]

[0038]

[0039] Here, is the Fourier series of the magnetomotive force, and is the magnitude of the magnetomotive force harmonic, and is the order of the magnetomotive force harmonic, and is the number of permanent magnet pole pairs of the inner rotor, and is the rotational speed of the inner rotor, and can be the angular position of the magnetomotive force.

[0040] Furthermore, permeance (the reciprocal of magnetic resistance) can be represented as a periodic waveform because air gaps with high magnetic resistance and iron cores with low magnetic resistance (pole pieces) are spatially repeated. Permeance can be expressed as a Fourier series as follows:

[0041] [Mathematical Formula 2]

[0042]

[0043] Here, It is the Fourier series of permeance, and is the permeance offset, and is the magnitude of the permeance harmonic, and j is the order of the permeance harmonic, and is the number of pole pieces, can be an angular position of permeance.

[0044] The magnetic flux density can be expressed as the product of the magnetomotive force and permeance described above. In this case, since the offset component (P0) of the magnetomotive force and permeance and the fundamental component (k=1, j=1) account for most of the total magnitude, harmonics of the second order or higher can be ignored, and accordingly, the modulated magnetic flux density can be obtained from the product of the magnetomotive force and permeance of the inner rotor permanent magnet. Therefore, the magnetic flux density of the modulated inner permanent magnet is given by the following mathematical formula.

[0045] [Mathematical Formula 3]

[0046]

[0047] For the magnetic flux density of the 4-pole inner rotor permanent magnet to be magnetically coupled with the magnetic flux density of the 28-pole outer rotor permanent magnet, the order of time (+ ) and the order of space( ) must match. When the magnetic flux density generated by the unmodulated 28-pole outer rotor permanent magnet is expressed as in Equation 4 below, if the spatial and temporal orders of the magnetic flux density of the modulated inner rotor permanent magnet and the magnetic flux density of the unmodulated outer rotor permanent magnet are matched, the relationship for determining the number of pole pieces and the gear ratio (including both reduction ratio and torque ratio) can be defined as in Equation 4 below.

[0048] [Mathematical Formula 4]

[0049]

[0050] Here, is the magnetic flux density of the outer rotor permanent magnet, and is the magnitude of the magnetic flux density component, and is the number of pole pairs of the outer rotor permanent magnets, and is the rotational speed of the outer rotor, and is the phase difference between the modulated flux and the flux by the pole piece, and can be the angular position of the magnetic flux density of the outer rotor permanent magnet.

[0051] [Mathematical Formula 5]

[0052]

[0053] [Mathematical Formula 6]

[0054]

[0055] Here It can be a gear ratio (or reduction ratio).

[0056] [Mathematical Formula 7]

[0057]

[0058] When magnetic coupling occurs between the magnetic flux density of the modulated inner rotor permanent magnet and the magnetic flux density of the unmodulated outer rotor permanent magnet, if the magnitude of the time order is the same but the sign is opposite, the inner rotor and the outer rotor will rotate in opposite directions.

[0059] When each element (Component 1 to Component 3) of the above mathematical formula is defined as follows, for the magnetic flux density of Component 1 and the outer rotor permanent magnet to be coupled, the number of poles of the inner rotor and the outer rotor permanent magnet must be the same and the rotational speed must be the same, regardless of the number of pole pieces. This is the same as the motor operating principle in which the rotor rotates according to the rotating magnetic field of a stator with the same number of poles and speed. In this case, Component 2 and Component 3, which are not coupled, become losses.

[0060] In Component 2, when the magnetic flux densities of the modulated inner rotor permanent magnet and the outer rotor permanent magnet are combined, the magnitude and sign of the spacetime order are both the same, so the outer and inner rotors rotate in the same direction. On the other hand, in Component 3, when the magnetic flux densities of the modulated inner rotor permanent magnet and the outer rotor permanent magnet are combined, the magnitude of the time order is the same but the sign is opposite, so the outer and inner rotors rotate in opposite directions.

[0061] [Component 1]

[0062]

[0063] [Component 2]

[0064]

[0065] [Component 3]

[0066]

[0067] In FIG. 2 and below, a magnetic gear structure is included that forms a notch in a pole piece and rotates it in order to convert the gear ratio of the magnetic gear to a desired value. Hereinafter, a magnetic gear according to various embodiments of the present disclosure will be described in detail.

[0069] FIG. 2 is a cross-sectional view of a magnetic gear including a notched pole piece according to one embodiment of the present invention.

[0070] Referring to FIG. 2, a cross-section of a magnetic gear (200) according to one embodiment of the present invention is illustrated. A magnetic gear (200) according to one embodiment of the present invention may include a stator (210), a first rotor (220), and a second rotor (230).

[0071] The stator (210) is formed in a fixed state, and a first magnetomotive force can be formed when electricity flows through the provided coil. For example, the stator (210) may be formed by being fixed inside the magnetic gear (200). Additionally, the stator (210) may include an electromagnet (260) that includes a coil. For example, the stator (210) may include a direct current (DC) field coil. The DC field coil may include a set of coils wound around the poles of the motor to generate a magnetic field.

[0072] The first rotor (220) may be formed to be rotatable outside the stator (210). Additionally, the first rotor (220) may be formed with alternating magnetic and non-magnetic materials. For example, the first rotor (220) may be a low-speed rotor in which pole pieces (240) and air gaps (245) are alternately formed.

[0073] The pole piece (240) included in the first rotor (220) may include a notch (250) shape. At least one notch (250) formed in the pole piece (240) may be included, and the notch (250) of the pole piece (240) may be formed on the outer or inner side of the pole piece.

[0074] The second rotor (230) may be formed to be rotatable outside the first rotor (220). Additionally, the second rotor (230) may have a second magnetomotive force formed by a magnet. For example, the second rotor (230) may include a permanent magnet, and the second magnetomotive force may be formed by said permanent magnet.

[0075] The first rotor (220) can be rotated by the magnetic coupling of the first magnetomotive force and the second magnetomotive force, and the ratio of the speed of the first rotor (220) to the speed of the second rotor (230) can be converted by the electricity flowing through the stator (210). In addition, the rotational direction of the first rotor (220) and the second rotor (230) can be converted by the electricity flowing through the stator (210).

[0076] The magnetic gear (200) of the first rotor (220) and the second rotor (230) can determine the speed relationship equation for the first rotor (220) including the pole piece, the second rotor (230) formed on the outer side of the first rotor (220), the first rotor (220), and the stator (210) formed on the inner side. At this time, since an electromagnet is formed in the stator (210) instead of a permanent magnet, speed control of the rotating magnetic field can be performed, and the speed ratio of the physically rotating second rotor (230) and the first rotor (220) can be controlled.

[0078] FIG. 3 illustrates the principle of operation for changing the gear ratio of a magnetic gear according to one embodiment of the present disclosure.

[0079] The magnetic gear (300) of Fig. 3 may be the same as the magnetic gear (200) described in Fig. 2.

[0080] The magnetomotive force generated by the permanent magnet of the second rotor (330) of the magnetic gear (300) can be calculated as follows:

[0082] [Mathematical Formula 8]

[0083]

[0084] Here, is the speed of the second rotor (330), and ☐ can represent the number of pole pairs of the second rotor (330), and a can represent the harmonic order.

[0085] When the rotational speed of the first rotor (320) is reflected in the magnetic gear (300), the relative permeance can be derived as shown in the mathematical formula below.

[0087] [Mathematical Formula 9]

[0088]

[0089] Here, is the rotational speed of the first rotor (320), and ε is the permeance offset, and j can be the harmonic order. In this case, The preceding sign may be set to - if the rotation direction of the first rotor (320) and the second rotor (330) is the same, and to + if the rotation direction of the first rotor (320) and the second rotor (330) is opposite. Below, the case where the rotation direction of the second rotor (330) and the first rotor (320) is the same is assumed and explained.

[0090] Also, magnetomotive force (F), offset of permeance ( The magnetic flux density of the second rotor (330) permanent magnet induced by the first rotor (320) rotating by considering only the fundamental wave component is as shown in the mathematical formula below.

[0091] [Mathematical Formula 10]

[0092]

[0093] Here, may be the number of pole pieces included in the first rotor (220).

[0094] Additionally, for the magnetic coupling of the first magnetomotive force formed by the electromagnet of the stator (310) and the second magnetomotive force formed by the permanent magnet of the second rotor (230), the spacetime order of the magnetic flux density of the electromagnet of the stator (310) and the magnetic flux density of the permanent magnet of the second rotor (330) may be matched. At this time, the number of pole pieces of the first rotor (320) may be determined by the match of the spacetime order.

[0095] [Mathematical Formula 11]

[0096]

[0097] Here, The stator (310) may be a pair of poles. Also, The sign of the first rotor (320) and the second rotor (330) can be determined by whether they rotate in the same direction.

[0098] On the other hand, the speed relationship of the magnetic gear (300) of the present disclosure may include the speeds of the second rotor (330), the first rotor (320), and the outer rotating magnetic field.

[0099] [Mathematical Formula 12]

[0100]

[0101] Here, can be the outer rotating magnetic field speed.

[0102] In addition, the gear ratio can be calculated as follows:

[0104] [Mathematical Formula 13]

[0105]

[0106] Here, It can represent the gear ratio.

[0108] FIG. 4 relates to a method for inducing a change in the number of pole pieces of a magnetic gear by adjusting the number of pairs of poles according to one embodiment of the present disclosure.

[0109] The magnetic gear (400) of FIG. 4 may be the same or similar to the magnetic gear described in FIG. 2 and FIG. 3.

[0110] FIG. 4 describes a method for demonstrating the effect of changing the number of first rotors including notched pole pieces by changing the number of paired poles of the stator. Here, it is explained that one notch is applied to the pole piece and six pole pieces are included in the first rotor.

[0111] Magnetic gears can adjust the gear ratio in various modes by changing the number of pairs of poles in the stator.

[0112] First, in the first mode (405), by adjusting the paired pole value of the stator (410) to 2, the pole piece (420) included in the first rotor (415) can be applied as if it were not notched. At this time, the first rotor (415) can operate as if it contains 6 pole pieces. When the first mode is utilized, the number of pole pieces becomes smaller than when notched, and the gear ratio also becomes relatively lower.

[0113] In the second mode (455), by adjusting the paired pole value of the stator (460) to 8, the pole piece (470) included in the first rotor (415) can be applied as if it were separated by notching. At this time, the first rotor (415) can operate as if it contains 12 pole pieces (470). When the second mode is utilized, the number of pole pieces increases compared to when notching is not applied, and the gear ratio also becomes relatively higher.

[0114] Therefore, by adjusting the bipolar value of the stator, it is possible to achieve the same effect as applying two or more pole pieces using a single pole piece.

[0115] When the pole piece (480) is made large and the pole piece (485) is made small, when applied to the permeance (490) calculation formula, it can be confirmed that the permeance (490) decreases as the number of pole pieces (475) increases.

[0116] The permeance of the pole piece can be determined by the magnetic resistance that changes periodically according to the electrical angle (495) in the air gap.

[0118] FIGS. 5A and 5B illustrate a mode for inducing a gear ratio of a magnetic gear by adjusting the number of inner / outer poles according to one embodiment of the present disclosure.

[0119] FIGS. 5A and 5B describe a method for determining the gear ratio of a magnetic gear using a pole piece including a notch and controlling the number of stator poles as in FIG. 4.

[0120] Referring to FIG. 5a, the stator winding (520) is controlled to obtain a pair of poles (pp w By changing the number of pole pieces (525), the effect of changing the gear ratio (530) when the number of pole pairs of the second rotor is 4 can be achieved.

[0121] First, in the no-load (505) mode, current is not applied to the stator winding (520) so that the number of poles is controlled to 0, and the pole piece is applied in its original form and the gear ratio (530) may not be transmitted.

[0122] In the first mode (510), current is applied to the stator winding (520) to control the number of paired poles to 2, so that the pole piece is recognized as not having a notch applied, so that it is applied as having 6 pole pieces, and the gear ratio can be determined to be 1.5.

[0123] In the second mode (515), current is applied to the stator winding (520) to control the number of paired poles to 8, so that the pole piece is recognized as having a notch applied and is applied as having 12 pole pieces, and the gear ratio can be determined to be 3.

[0124] In FIG. 5b, various indicators can be shown for the case (565) in which the number of stator poles is set to 16 / 4 as in FIG. 5a, as well as for the case (550) in which the number of stator poles is set to 12 / 2. In this case, considering the gear ratio to be controlled, five pole pieces with notches applied to match the number of stator poles may be included. Thus, the number of pole pieces with notches applied can be adjusted based on the gear ratio to be controlled.

[0125] In the case (550) where the number of stator poles is set to 12 / 2, the gear (555) with a stator pair of poles of 6 and the gear (560) with a stator pair of poles of 1 can be distinguished.

[0126] When the second rotor pole pair number is assumed to be 4, the gear (555) with the stator pole pair number 6 is recognized as containing 10 pole pieces and the gear ratio can be determined to be 2.5.

[0127] In a gear (560) with 1 pair of stator poles, it is recognized that 5 pole pieces are included, and the gear ratio can be determined to be 1.25.

[0128] At this time, the difference in gear ratio can be controlled to 1.25.

[0129] Figure 5c shows the results of torque analysis in a magnetic gear with a pole piece including stator pair pole control and notch.

[0131] FIG. 6 shows a cross-sectional view of an internal magnetic gear according to one embodiment of the present disclosure.

[0132] The magnetic gear (600) of FIG. 6 may include the same or similar functions as the magnetic gear described in FIG. 1 to FIG. 5.

[0133] The internal magnetic gear (600) may include a stator (610), a first rotor (620), and a second rotor (630).

[0134] In the internal type magnetic gear (600), the stator (610) may be located on the outside of the first rotor (620), and the second rotor (630) may be located on the inside of the first rotor (630).

[0135] The stator (610) is formed in a fixed state, and when electricity flows through the provided coil, a first magnetomotive force can be formed.

[0136] The first rotor (620) may be formed to be rotatable within the stator (610). Additionally, the first rotor (620) may include a pole piece with a notch formed therein. The first rotor (620) may be a low-speed rotor that rotates at a relatively low speed.

[0137] The second rotor (630) can be formed to be rotatable inside the first rotor (620). Additionally, the second rotor (630) can generate a second magnetic force by a provided magnet.

[0138] The first rotor (620) can be rotated by the magnetic coupling of the first magnetomotive force and the second magnetomotive force, and the ratio of the speed of the first rotor (620) to the speed of the second rotor (630) can be converted by the electricity flowing through the stator (610). In addition, the rotational direction of the first rotor (620) and the second rotor (630) can be converted by the electricity flowing through the stator (610).

[0140] FIG. 7 is a cross-sectional view of a structure of pole pieces with notches formed therein included in a first rotor according to one embodiment of the present disclosure.

[0141] The pole piece of FIG. 7 may include an inner notched pole piece (705) or an outer notched pole piece (710).

[0142] The inner notched pole piece (705) may include a notched portion (720) and a flat portion (715). The inner notched pole piece (705) may have a notch formed in the inner part of the magnetic gear.

[0143] The outer notched pole piece (710) may include a notched portion (730) and a flat portion (725). The outer notched pole piece (710) may have a notch formed in the outer part of the magnetic gear.

[0144] Both the inner notched pole piece (705) and the outer notched pole piece (710) can be applied to an internal rotating magnetic gear and an external rotating magnetic gear.

[0145] Both the inner notched pole piece (705) and the outer notched pole piece (710) may include multiple notches in a single pole piece.

[0147] FIG. 8 is a flowchart illustrating a method for generating and controlling a magnetic gear according to one embodiment of the present disclosure.

[0148] The magnetic gear of FIG. 8 may be the same or similar to the magnetic gear described in FIG. 1 to 7.

[0149] FIG. 8 may be a method performed in a control device for generating and controlling magnetic gears.

[0150] In step S810, the control device can determine the gear ratio to be used for the magnetic gear and the rotational direction of the rotors of the magnetic gear. For example, depending on the mode, the gear ratio can be determined to be 3 or 1.5 so that the difference in the gear ratio is 1.5. Additionally, it can determine whether the first rotor and the second rotor of the magnetic gear will rotate in the same direction or in different directions.

[0151] In step S820, the control device can determine the number of pole pieces to be included in the first rotor and the number of permanent magnet pole pairs of the second rotor based on the determined gear ratio. At this time, different mathematical formulas may be applied depending on whether the rotational direction of the rotors is the same or opposite. Here, mathematical formula 14 may be applied.

[0152] [Mathematical Formula 14]

[0153] -(Rotation in the same direction)

[0154] -(Rotate in the opposite direction)

[0155] For example, assuming there is one notch per pole piece, if the gear ratio is 3, the number of pole pieces is determined to be 6, and the number of permanent magnet pole pairs of the second rotor can be determined to be 4. In this case, the gear ratio can be determined to be + or - depending on the direction.

[0156] In step S830, the number of low gear ratio pole pairs of the stator can be determined based on the lower gear ratio among the gear ratios determined in steps S810 and S820. The number of low gear ratio pole pairs can be calculated as follows.

[0157] [Mathematical Formula 15]

[0158]

[0159] In step S840, the number of high gear ratio pole pairs of the stator for a high gear ratio can be determined in a manner similar to that in step S830. The number of high gear ratio pole pairs can be calculated as follows. At this time, the number of notches is 1 (2N p It can represent an operation expression when ).

[0161] [Mathematical Formula 16]

[0162]

[0163] At this time, depending on the number of notches (N p It can be calculated by multiplying by +1.

[0164] In the S850 stage, the number of slots in the stator can be determined. The number of slots can be determined as twice the number of pole pairs of the high gear ratio.

[0166] [Mathematical Formula 17]

[0167]

[0168] For example, if the number of pole pieces is 6 and there is 1 notch, the number of low gear ratio pole pairs can be 2 and the number of high gear ratio pole pairs can be 8. In this case, the number of slots can be determined to be 16, which is twice the number of high gear ratio pole pairs.

[0169] In step S860, the magnetic gear can be controlled by distinguishing modes based on the operating gear ratio through DC current control. That is, depending on the mode of the operating gear ratio, the current can be controlled based on the number of poles corresponding to the low gear ratio and high gear ratio determined in steps S830 and S840.

[0171] The operation of the magnetic gear or control device according to the above-described disclosure may be implemented as computer-readable code on a computer-readable recording medium. Computer-readable recording media include all types of recording media in which data that can be decoded by a computer system is stored. Examples include ROM (Read Only Memory), RAM (Random Access Memory), magnetic tape, magnetic disk, flash memory, optical data storage devices, etc. Additionally, computer-readable recording media may be distributed across computer systems connected via a computer network and may be stored and executed as code that can be read in a distributed manner.

[0172] The various operations of the methods described above may be performed by any suitable means capable of performing the corresponding functions. The means include, but are not limited to, various hardware and / or software component(s) and / or module(s), including application-specific integrated circuits (ASICs) or processors. Generally, where there are operations corresponding to the drawings, these operations may have corresponding relative means plus functional components having the same number.

[0173] The various exemplary logic blocks, modules, and circuits described in connection with this disclosure may be implemented or performed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions disclosed herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented by a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors coupled with a DSP core, or any other such configuration.

[0174] Furthermore, the aforementioned term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, database, or other data structure), verifying, etc. Additionally, "determining" may include receiving (e.g., receiving information), accessing (accessing data in memory), etc. Furthermore, "determining" may include resolving, selecting, choosing, establishing, etc.

[0175] A person skilled in the art to which this disclosure pertains will be able to make various modifications and variations without departing from the essential nature of the technical concept of this disclosure.

[0176] Accordingly, the embodiments exemplified in this disclosure are intended to explain, not limit, the technical concept of this disclosure, and the scope of the technical concept of this disclosure is not limited by these embodiments.

[0177] The scope of protection of the technical concept of the present disclosure shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of the technical concept of the present disclosure.

Claims

Claim 1 A magnetic gear comprising: a stator formed in a fixed state and having a first magnetomotive force formed when electricity flows through a provided coil; a first rotor formed to be rotatable outside the stator; and a second rotor formed to be rotatable outside the first rotor and having a second magnetomotive force formed by a provided permanent magnet, wherein the first rotor is formed alternately with magnetic and non-magnetic materials, and each of the magnetic materials is configured to include at least one notch structure. Claim 2 In claim 1, the at least one notch structure is formed on either the outer or inner side of the magnetic body, forming a magnetic gear. Claim 3 In claim 1, the total number of magnetic bodies included in the first rotor is a magnetic gear determined based on a predetermined gear ratio. Claim 4 In claim 1, the number of the magnetic bodies is identified as changed in the magnetic gear based on the change in the number of pole pairs of the fixed magnet. Claim 5 A magnetic gear according to claim 4, wherein the number of magnetic bodies is identified differently in the magnetic gear in accordance with whether the notch is applied, which is determined based on the change in the number of pole pairs of the fixed magnet, and wherein the number of magnetic bodies identified in the magnetic gear when the notch is applied is greater than the number of magnetic bodies identified in the magnetic gear when the notch is not applied. Claim 6 In claim 5, a magnetic gear in which, when the above notch is applied, the number of magnetic bodies identified in the magnetic gear increases in proportion to the number of notches included in one magnetic body. Claim 7 In paragraph 4, the gear ratio of the magnetic gear is determined based on a change in the number of pole pairs of the stator. Claim 8 In claim 1, the magnetic gear in which the speed of the first rotor is slower than the speed of the second rotor. Claim 9 In claim 1, the gear ratio of the magnetic gear increases in proportion to the number of magnetic bodies. Claim 10 A magnetic gear comprising: a stator formed in a fixed state and having a first magnetomotive force formed when electricity flows through a provided coil; a first rotor formed to be rotatable inside the stator; and a second rotor formed to be rotatable inside the first rotor and having a second magnetomotive force formed by a provided permanent magnet, wherein the first rotor is configured such that a magnetic body and a non-magnetic body are alternately formed, and each of the magnetic bodies is configured to include at least one notch structure.

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