Motor symmetric rotor structure with magnetic field conversion and harmonic suppression functions

Abstract

The invention discloses a motor symmetric rotor structure with magnetic field conversion and harmonic suppression functions. Cage bars are sequentially a first-layer cage bar, a second-layer cage bar and a third-layer cage bar from outside to inside in the radial direction. Every two cage bars in one layer are short-circuited; part of the second-layer cage bars form a second-layer cage bar connecting loop according to the fifth harmonic polar distance so as to sense the fifth harmonic; part of the three-layer cage bars form a three-layer cage bar connection loop according to the seventh harmonic polar distance so as to sense the seventh harmonic; a second-layer diode loop / a third-layer diode loop is correspondingly connected in parallel with the second-layer cage bar connecting loop / the third-layer cage bar connecting loop, the second-layer diode loop / the third-layer diode loop is connected in parallel with the second-layer cage bar connecting loop / the third-layer cage bar connecting loop, the second-layer diode loop / the third-layer diode loop adopts a parallel connection mode shared by a single harmonic wave induction cage bar, and corresponding forward fifth and seventh harmonic waves are respectively induced in closed diode direct-current loops; magnetic fields of N and S pole areas of the permanent magnet can be enhanced. The vibration of the permanent magnet motor can be suppressed, the consumption of permanent magnet materials is reduced, and the performance and efficiency of the permanent magnet motor are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to an improved structure of a permanent magnet motor rotor. Background Art

[0002] With the continuous development of modern industry, various industries have increasingly stringent requirements for motor vibration control. Although permanent magnet motors have shown certain advantages in many aspects, the existing structure still exposes a series of defects that cannot be ignored.

[0003] On the one hand, the utilization rate of the permanent magnet motor rotor space needs to be improved, and it has not been fully and efficiently utilized, which has largely restricted the improvement of motor efficiency. On the other hand, the harmonic problem between the stator and rotor, especially the vibration caused by the fifth and seventh harmonics, has become a key challenge facing current permanent magnet motors. The existing motor rotor structure is difficult to effectively suppress the harmonics in the stator and rotor air gap, which leads to a significant increase in motor vibration and seriously affects the stability of motor operation. In addition, the existing technology has great limitations in harmonic magnetic field conversion and cannot achieve effective conversion of magnetic field harmonics.

[0004] Therefore, the present invention innovatively proposes a motor symmetrical rotor structure with magnetic field conversion and harmonic suppression functions. The structure aims to achieve effective magnetic field conversion, significantly reduce motor vibration, save permanent magnet materials, and comprehensively improve the performance and reliability of the motor to meet the urgent needs of modern industry for high-performance motors. Summary of the invention

[0005] The object of the present invention is to provide a motor symmetrical rotor structure with magnetic field conversion and harmonic suppression functions.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A symmetrical rotor structure of a motor with magnetic field conversion and harmonic suppression functions, comprising cage bars, a rotor core and a permanent magnet, wherein the cage bars are divided into three layers along the radial direction, namely, a first layer of cage bars, a second layer of cage bars and a third layer of cage bars from the outside to the inside;

[0008] The cage bars of one layer are short-circuited in pairs to generate torque by induction current, thus realizing the self-starting of the motor.

[0009] Some of the second-layer cage bars are connected in short distances according to the fifth harmonic pole pitch to form a second-layer cage bar connection loop; in the second-layer cage bar connection loop, the second-layer cage bars are called second-layer induction harmonic cage bars, and the connection distance between every two second-layer induction harmonic cage bars corresponds to the fifth harmonic pole pitch, thereby inducing the fifth harmonic, which then offsets the fifth harmonic causing vibration in the air gap, and can effectively reduce the vibration of the motor;

[0010] Some three-layer cage bars are connected in short distance according to the seventh harmonic pole pitch to form a three-layer cage bar connection loop; in the three-layer cage bar connection loop, the three-layer cage bars are called three-layer induction harmonic cage bars, and the connection distance between every two three-layer induction harmonic cage bars corresponds to the seventh harmonic pole pitch, thereby inducing the seventh harmonic, which then offsets the seventh harmonic causing vibration in the air gap, and can effectively reduce the vibration of the motor;

[0011] A two-layer diode circuit / a three-layer diode circuit is also provided in parallel with the two-layer cage bar connection circuit / the three-layer cage bar connection circuit. The two-layer diode circuit / the three-layer diode circuit and the corresponding two-layer cage bar connection circuit / the three-layer cage bar connection circuit adopt a parallel connection mode shared by a single two-layer inductive harmonic cage bar / the three-layer inductive harmonic cage bar. The two-layer cage bar connection circuit / the three-layer cage bar connection circuit includes a diode. The diode has a unidirectional conduction characteristic and can induce positive fifth and seventh harmonics in a closed DC circuit. After harmonic coupling, the magnetic field of the N and S pole regions of the permanent magnet can be enhanced to reduce the permanent magnet material.

[0012] Furthermore, the second-layer cage bar connection loop / the third-layer cage bar connection loop only connects two loops in one wave cycle.

[0013] Furthermore, the first-layer cage bars, the second-layer cage bars and the third-layer cage bars are placed in the same slot of the rotor core and are evenly distributed.

[0014] Furthermore, the first-layer cage bars, the second-layer cage bars and the third-layer cage bars in the same slot are separated by insulating materials.

[0015] Further, the two-layer diode loop cage bar includes a shared two-layer inductive harmonic cage bar and a two-layer diode loop cage bar, and the two-layer diode loop cage bar is one of the remaining cage bars in the middle of the two-layer inductive harmonic loop;

[0016] The two ends of the two-layer diode loop cage bar are electrically connected to the two ends of the shared two-layer induction harmonic cage bar. One end of the loop contains a diode, and the other end of the loop contains only a wire, forming a one-way closed loop, and its conduction sequence is consistent with the magnetic poles of the permanent magnet; this loop contains only direct current, which can induce a positive fifth harmonic and couple with the fundamental wave generated by the permanent magnet, thereby enhancing the magnetic field in the N and S polar regions generated by the permanent magnet;

[0017] The three-layer diode loop includes a common three-layer inductive harmonic cage bar and a three-layer diode loop cage bar, and the three-layer diode loop cage bar is one of the remaining cage bars in the middle of the three-layer inductive harmonic loop;

[0018] The two ends of the three-layer diode loop cage bar are electrically connected to the shared three-layer induction harmonic cage bar respectively. One end of the loop contains a diode, and the other end of the loop contains only a wire, forming a unidirectional closed loop, and its conduction sequence is consistent with the permanent magnet pole; this loop only contains direct current, which can induce a positive seventh harmonic and couple with the fundamental wave generated by the permanent magnet, thereby enhancing the N and S pole magnetic fields generated by the permanent magnet.

[0019] Furthermore, in the two-layer diode loop / three-layer diode loop, only one diode is provided in each loop.

[0020] The beneficial effects of the present invention are:

[0021] 1. Through the unique design, the present invention shows functional advantages in that the rotor cage structure can accurately eliminate specific harmonic content in the air gap magnetic field and effectively suppress vibration during the operation of the motor. At the same time, it is effective in saving permanent magnet materials, reducing the dependence on permanent magnet materials, and thus significantly improving the operating efficiency of the motor.

[0022] 2. The cage bars of the present invention adopt a three-layer design. The second-layer cage bars and the third-layer cage bars can sense the fifth and seventh harmonics, thereby suppressing the fifth and seventh spatial harmonics in the air gap that cause motor vibration.

[0023] 3. The present invention is also provided with a two-layer diode circuit and a three-layer diode circuit. The two-layer cage bar connection circuit / three-layer cage bar connection circuit includes a diode. The diode has a unidirectional conduction characteristic to form a unidirectional closed circuit, and its conduction sequence is consistent with the magnetic poles of the permanent magnet. This circuit only contains direct current, which can induce positive fifth and seventh harmonics, and couple with the fundamental wave generated by the permanent magnet, thereby enhancing the N and S pole magnetic fields generated by the permanent magnet.

[0024] 4. The present invention can suppress the vibration of permanent magnet motors and improve the performance and efficiency of permanent magnet motors. With the improvement of motor operating efficiency, energy consumption can be significantly reduced, thereby reducing environmental pollution caused by energy production and use. This not only helps companies reduce operating costs, but also conforms to the general trend of global sustainable development and makes positive contributions to promoting the development of the green energy industry and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The schematic diagram of the connection of the first, second and third layers of cage bars at one end of the rotor;

[0026] Figure 2 The schematic diagram of the connection of the first, second and third layers of cage bars at the other end of the rotor;

[0027] Figure 3 This is the partial connection diagram of the two-layer cage bars at one end of the rotor;

[0028] Figure 4 This is the partial connection diagram of the two-layer cage bars at the other end of the rotor;

[0029] Figure 5 This is a partial connection diagram of the three-layer cage bars at one end of the rotor;

[0030] Figure 6 This is the partial connection diagram of the three-layer cage bars at the other end of the rotor;

[0031] Figure 7 This is the overall connection diagram of the first, second and third layers of cage bars at one end of the rotor;

[0032] Figure 8 This is the overall connection diagram of the first, second and third layers of cage bars at the other end of the rotor;

[0033] Fig. 9 This is the principle diagram of the harmonic induction of the second and third layers of cage bars;

[0034] Fig.10 This is the schematic diagram of the induced harmonics after the second and third layer cage diode circuits are turned on.

[0035] The drawings are only used for illustrative purposes and should not be construed as limitations on this patent. In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The present invention is intended to be more generally applied to permanent magnet motor rotor bars, so the present invention can be used in any practical application that is suitable for the specific application requirements.

[0037] During the manufacturing process of the motor, the rotor bars are made strictly according to the design requirements. When winding the bar winding, the tightness and uniformity of the winding must be ensured to improve the strength and stability of the induced magnetic field.

[0038] like Figures 1 to 10 As shown, this embodiment provides a motor symmetrical rotor structure with magnetic field conversion and harmonic suppression functions, including cage bars, rotor core 40, permanent magnets 50, shaft and diodes 60. Each component works together to construct a high-efficiency motor rotor system.

[0039] The cage bars are divided into three layers along the radial direction, from the outside to the inside (the one close to the permanent magnet 50 is the inside), which are the first layer of cage bars 10, the second layer of cage bars 20 and the third layer of cage bars 30. The first layer of cage bars 10, the second layer of cage bars 20 and the third layer of cage bars 30 are placed in the same slot of the rotor core 40 and are evenly distributed. The first layer of cage bars 10, the second layer of cage bars 20 and the third layer of cage bars 30 in the same slot are separated by insulating materials.

[0040] The cage bars 10 of one layer are short-circuited in pairs to generate torque by induction current, thereby realizing self-starting of the motor.

[0041] Some of the second-layer cage bars 20 are connected in short distances according to the fifth harmonic pole pitch (corresponding to 1 / 5 of the fundamental wave pitch) to form a second-layer cage bar connection loop; the second-layer cage bars are called second-layer induction harmonic cage bars, and the connection spacing between every two second-layer induction harmonic cage bars corresponds to the fifth harmonic pole pitch, thereby inducing the fifth harmonic, which then offsets the fifth harmonic causing vibration in the air gap, thereby effectively reducing the vibration of the motor.

[0042] Some three-layer cage bars 30 are connected in short distance according to the seventh harmonic pole pitch (corresponding to 1 / 7 of the fundamental wave pitch) to form a three-layer cage bar connection loop; in the three-layer cage bar connection loop, the three-layer cage bars are called three-layer induction harmonic cage bars, and the connection spacing of every two three-layer induction harmonic cage bars corresponds to the seventh harmonic pole pitch, thereby inducing the seventh harmonic, which then offsets the seventh harmonic causing vibration in the air gap, thereby effectively reducing the vibration of the motor.

[0043] Furthermore, the second-layer cage bar connection loop / the third-layer cage bar connection loop only connects two loops in one wave cycle.

[0044] A second-layer diode circuit / a third-layer diode circuit is also provided in parallel with the second-layer cage bar connection circuit / the third-layer cage bar connection circuit. The second-layer diode circuit / the third-layer diode circuit and the corresponding second-layer cage bar connection circuit / the third-layer cage bar connection circuit adopt a parallel connection method shared by a single second-layer inductive harmonic cage bar / the third-layer inductive harmonic cage bar.

[0045] The two-layer cage bar connection circuit / three-layer cage bar connection circuit includes a diode 60. The diode 60 has a unidirectional conduction characteristic and can induce positive fifth and seventh harmonics in a closed DC circuit. After harmonic coupling, the magnetic field in the N and S poles of the permanent magnet can be enhanced to reduce the permanent magnet material (that is, there is only the positive DC part of the fifth / seventh harmonic in the diode, and the sinusoidal harmonic only retains the positive part. After coupling, the positive part becomes the fundamental wave, which enhances the permanent magnet magnetic field. Therefore, the permanent magnet itself can have less material and the same magnetic field as the original).

[0046] When the two-layer diode loop / three-layer diode loop is connected, the remaining cage bars of the second-layer cage bar 20 and the third-layer cage bar 30 (that is, the cage bars not involved in the second-layer cage bar connection loop / three-layer cage bar connection loop) can be used. Specifically:

[0047] As shown in Figure 3 and Figure 4 shown, the two-layer diode loop bar includes a shared two-layer induced harmonic bar and a two-layer diode loop bar. The two-layer diode loop bar is one of the remaining bars in the middle of the two-layer induced harmonic loop. The two ends of the two-layer diode loop bar are electrically connected to the two ends of the shared two-layer induced harmonic bar respectively. One end of the loop contains a diode, and the other end of the loop contains only a wire, forming a unidirectional closed loop. Its conduction sequence is consistent with the permanent magnet poles. This loop only contains direct current, can induce positive fifth harmonic, and is coupled with the fundamental wave generated by the permanent magnet, so as to enhance the magnetic field in the N and S pole regions generated by the permanent magnet.

[0048] As shown in Figure 5 and Figure 6 shown, the three-layer diode loop includes a shared three-layer induced harmonic bar and a three-layer diode loop bar. The three-layer diode loop bar is one of the remaining bars in the middle of the three-layer induced harmonic loop. The two ends of the three-layer diode loop bar are electrically connected to the shared three-layer induced harmonic bar respectively. One end of the loop contains a diode, and the other end of the loop contains only a wire, forming a unidirectional closed loop. Its conduction sequence is consistent with the permanent magnet poles. This loop only contains direct current, can induce positive seventh harmonic, and is coupled with the fundamental wave generated by the permanent magnet, so as to enhance the magnetic field in the N and S pole regions generated by the permanent magnet.

[0049] In the two-layer diode loop / three-layer diode loop, only one diode is set in each loop.

[0050] The harmonic magnetic fields induced by the above two-layer bars and three-layer bars are independent of each other.

[0051] The following takes the total number of bars Z = 70 and the two-pole (one pair of poles) motor P = 1 as an example for detailed description.

[0052] For the fundamental magnetic field, the number of bars corresponding to the fundamental pole pitch (pieces) is:

[0053]

[0054] That is, under the fundamental magnetic field, from the perspective of spatial distribution, one fundamental pole pitch spans 35 bars, and every 35 bars are short-circuited once. Figure 6 It is the overall connection diagram of the one-layer bars.

[0055] For the fifth harmonic, according to the formula

[0056]

[0057] When v = 5, the fifth harmonic pole pitch is 1 / 5 of the fundamental pole pitch, that is, the number of bars corresponding to the fifth harmonic pole pitch (pieces) N5 for:

[0058] Therefore, every two cage bars are short-circuited at a distance of 7-1=6 cage bars compared to the induction fundamental wave. The principle is as follows Fig. 9 The second layer of cage bars is shown in the figure. The specific connection method is as follows: Figure 3 and Figure 4 As shown. The No. 70 second-layer cage bar is connected to the No. 7 second-layer cage bar (the No. 70 second-layer cage bar and the No. 7 second-layer cage bar are second-layer induction harmonic cage bars, and the No. 70 second-layer cage bar is used as a shared second-layer induction harmonic cage bar). Figure 7 and Figure 8 This is the overall connection diagram.

[0059] The two ends of the two-layer diode loop cage bar (No. 4 two-layer cage bar) are connected to the shared two-layer induction harmonic cage bar (No. 70 two-layer cage bar) loop. One end of the loop contains a diode, and the other end of the loop only contains a wire, forming a one-way loop, and its conduction sequence is consistent with the permanent magnet pole. This loop contains only direct current, which can induce a positive fifth harmonic and couple with the fundamental wave generated by the permanent magnet, thereby enhancing the N and S polar magnetic fields generated by the permanent magnet.

[0060] Similarly, for the seventh harmonic (v=7), the pole pitch is 1 / 7 of the fundamental pole pitch, that is, the number of cage bars corresponding to the seventh harmonic pole pitch is N 7 for:

[0061]

[0062] Therefore, every two cage bars are short-circuited at a distance of 5-1=4 cage bars compared to the induction fundamental wave. The principle is as follows Fig. 9 The three-layer cage bar is shown in the figure. The specific connection method is as follows Figure 5 and Figure 6 As shown, the No. 69 three-layer cage bar is connected to the No. 4 three-layer cage bar (the No. 69 three-layer cage bar and the No. 7 three-layer cage bar are three-layer induction harmonic cage bars, and the No. 69 three-layer cage bar is used as a shared three-layer induction harmonic cage bar).

[0063] The two ends of the three-layer diode loop cage bar (No. 2 three-layer cage bar) are connected to the shared three-layer induction harmonic cage bar (No. 69 three-layer cage bar) loop. One end of the loop contains a diode, and the other end of the loop only contains a wire, forming a one-way loop, and its conduction sequence is consistent with the permanent magnet pole. This loop contains only direct current, which can induce the positive seventh harmonic and couple with the fundamental wave generated by the permanent magnet, thereby enhancing the N and S polar magnetic fields generated by the permanent magnet. Figure 5 The overall connection diagram

[0064] Through the above scheme, the present invention uses a layer of cage bars to induce current and generate torque, thereby realizing self-starting of the motor. The cage bars of the second and third layers are partially connected in a short-distance manner, which can induce the fifth and seventh harmonics, and then offset each other with the fifth and seventh harmonics that cause vibration in the air gap, which can effectively reduce the vibration of the motor. The remaining cage bars of the second and third layers are connected through diodes and are connected in parallel with the harmonic circuits of the second and third layers of cage bars, respectively. The diode DC circuit can induce the corresponding positive fifth and seventh harmonics. After coupling, these harmonics can enhance the fundamental magnetic field of the N and S poles of the permanent magnet, thereby reducing the use of rare earth materials in the permanent magnet. This structure can specifically eliminate the harmonic content in the air gap magnetic field, suppress motor vibration, save permanent magnet materials, and effectively improve the operating efficiency of the motor.

[0065] In practical applications, the motor of the present invention can be applied to multiple fields according to different needs, such as driving various machines in industrial production, acting as a power source for electric buses in the field of transportation, and combining with hydropower generation and geothermal power generation systems in the field of new energy to improve energy utilization efficiency.

[0066] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

[0067] If the words "first", "second", etc. are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only to facilitate the description of the present invention and simplify the description. Unless otherwise stated, the above words have no special meaning.

[0068] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0069] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A symmetrical rotor structure of a motor with magnetic field conversion and harmonic suppression functions, comprising cage bars, a rotor core and a permanent magnet, characterized in that: The cage bars are divided into three layers along the radial direction, namely, the first layer of cage bars, the second layer of cage bars and the third layer of cage bars from the outside to the inside; The cage bars of one layer are short-circuited in pairs to generate torque by induction current, thus realizing the self-starting of the motor. Some of the second-layer cage bars are connected in short distances according to the fifth harmonic pole pitch to form a second-layer cage bar connection loop; in the second-layer cage bar connection loop, the second-layer cage bars are called second-layer induction harmonic cage bars, and the connection distance between every two second-layer induction harmonic cage bars corresponds to the fifth harmonic pole pitch, thereby inducing the fifth harmonic, which then offsets the fifth harmonic causing vibration in the air gap, and can effectively reduce the vibration of the motor; Some three-layer cage bars are connected in short distance according to the seventh harmonic pole pitch to form a three-layer cage bar connection loop; in the three-layer cage bar connection loop, the three-layer cage bars are called three-layer induction harmonic cage bars, and the connection distance between every two three-layer induction harmonic cage bars corresponds to the seventh harmonic pole pitch, thereby inducing the seventh harmonic, which then offsets the seventh harmonic causing vibration in the air gap, and can effectively reduce the vibration of the motor; A two-layer diode circuit / three-layer diode circuit is also provided in parallel with the two-layer cage bar connection circuit / three-layer cage bar connection circuit. The two-layer diode circuit / three-layer diode circuit and the corresponding two-layer cage bar connection circuit / three-layer cage bar connection circuit adopt a parallel connection mode shared by a single two-layer inductive harmonic cage bar / three-layer inductive harmonic cage bar; the two-layer cage bar connection circuit / three-layer cage bar connection circuit includes a diode. The diode has a unidirectional conduction characteristic and can induce positive fifth and seventh harmonics in a closed DC circuit. After harmonic coupling, the magnetic field in the N and S pole regions of the permanent magnet can be enhanced to reduce the permanent magnet material.

2. The symmetrical rotor structure of the motor with magnetic field conversion and harmonic suppression functions according to claim 1, characterized in that: The second-layer cage bar connection loop / third-layer cage bar connection loop only connects two loops in one wave cycle.

3. The symmetrical rotor structure of the motor with magnetic field conversion and harmonic suppression functions according to claim 1 is characterized in that: In each rotor cage bar slot, there is one first-layer cage bar, one second-layer cage bar and one third-layer cage bar, and the three cage bars are evenly distributed.

4. The symmetrical rotor structure of the motor with magnetic field conversion and harmonic suppression functions according to claim 1 or 3, characterized in that: The first-layer cage bars, the second-layer cage bars and the third-layer cage bars in the same slot are separated by insulating materials.

5. The symmetrical rotor structure of the motor with magnetic field conversion and harmonic suppression functions according to claim 1, characterized in that: The two-layer diode loop cage bar includes a shared two-layer inductive harmonic cage bar and a two-layer diode loop cage bar, and the two-layer diode loop cage bar is one of the remaining cage bars in the middle of the two-layer inductive harmonic loop; The two ends of the two-layer diode loop cage bar are electrically connected to the two ends of the shared two-layer induction harmonic cage bar. One end of the loop contains a diode, and the other end of the loop contains only a wire, forming a unidirectional closed loop, and its conduction sequence is consistent with the magnetic poles of the permanent magnet; this loop contains only direct current, which can induce a positive fifth harmonic and couple with the fundamental wave generated by the permanent magnet, thereby enhancing the N and S polar magnetic fields generated by the permanent magnet; The three-layer diode loop includes a common three-layer inductive harmonic cage bar and a three-layer diode loop cage bar, and the three-layer diode loop cage bar is one of the remaining cage bars in the middle of the three-layer inductive harmonic loop; The two ends of the three-layer diode loop cage bar are electrically connected to the shared three-layer induction harmonic cage bar. One end of the loop contains a diode, and the other end of the loop contains only a wire, forming a unidirectional closed loop, and its conduction sequence is consistent with the permanent magnet pole; this loop only contains direct current, which can induce a positive seventh harmonic and couple with the fundamental wave generated by the permanent magnet, thereby enhancing the N and S polar magnetic fields generated by the permanent magnet.

6. The symmetrical rotor structure of a motor with magnetic field conversion and harmonic suppression functions according to claim 1 or 5, characterized in that: In a two-layer diode loop / three-layer diode loop, only one diode is provided in each loop.

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