Built-in tangential mixed magnetic steel magnetism gathering type permanent magnet rotor

Abstract

A built-in tangential mixed magnetic steel magnetism gathering type permanent magnet rotor relates to the technical field of motors, the rotor comprises a rotor iron core and a rotating shaft, the rotor iron core is provided with a plurality of permanent magnet units which are symmetrically arranged around the axis of the rotor iron core, and the permanent magnet rotor is characterized in that each permanent magnet unit comprises a middle magnetic steel, middle air permanent magnet grooves and radial magnetic steel are arranged between the adjacent permanent magnet units, the middle air permanent magnet grooves and the radial magnetic steel are arranged on the q shaft, the middle air permanent magnet grooves are arranged on the inner sides of the radial magnetic steel, and the middle magnetic steel and the adjacent radial magnetic steel on the two sides of the middle magnetic steel are arranged in a U shape. The rotor provided by the utility model can reduce motor noise and torque ripple.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technical field, especially a kind of built-in tangential mixed magnetic steel magnetic type permanent magnet rotor technology. BACKGROUND

[0002] Current permanent magnet synchronous motor suitable for electric vehicle and industrial automation, there is torque fluctuation, power and torque density is low, overload capacity is low and poor reliability and other defects, difficult to meet the requirements, drive motor restricts the research and development of Chinese electric vehicle and industrial automation and its industrialization process.

[0003] For a long time, improving power and torque density, reducing motor torque fluctuation is one of the priorities of motor research at home and abroad. One of the ways to improve power density is to increase speed, but it needs to increase the input power voltage frequency, resulting in the increase of high harmonic, permanent magnet rotor loss and motor temperature rise;Effective way to improve power density and torque density is to improve air gap flux and air gap flux density, thereby, improve no-load back emf, reduce leakage, for this, existing built-in permanent magnet synchronous motor (IPMSM), take two measures to resist leakage together, improve air gap flux density: 1) air permanent magnet slot is arranged at both ends of built-in magnetic steel, namely non-magnetic flux barrier, which plays a role of magnetic separation, improves air gap flux density;2) set up magnetic bridge between the two ends of permanent magnet pole (q axis) and rotor outer edge, improve air gap flux density.

[0004] The thinner the thickness of the magnetic bridge is designed, the more saturated the magnetic circuit is, and the smaller the magnetic permeability coefficient is, so as to limit the leakage, increase the effective flux and improve the air gap flux density;But the magnetic bridge is located at the outer edge of the rotor, and the thickness of the magnetic bridge is too narrow, the mechanical strength is poor, the motor manufacturing process and manufacturing cost are improved, the service life of the rotor silicon steel sheet punching die is reduced;The maximum stress of the rotor is inversely proportional to the thickness of the magnetic bridge and proportional to the square of the speed, and there is a hidden danger of plastic deformation of the rotor at high speed, so the motor is not safe at high speed. Therefore, the existing IPMSM, the magnetic bridge, is difficult to isolate the leakage, improve the air gap flux density to improve the power density of the motor and the safety of the motor at high speed. UTILITY MODEL CONTENTS

[0005] In view of the defects in the prior art, the utility model solves the technical problems to provide a built-in tangential mixed magnetic steel magnetic type permanent magnet rotor which can improve the air gap flux density, thereby improving the torque density and power density, and reducing the motor noise and torque fluctuation.

[0006] In order to solve the above technical problems, the utility model provides a built-in tangential mixed magnetic steel magnetic type permanent magnet rotor, which comprises a rotor core and a rotating shaft, the rotor core is provided with a plurality of permanent magnet units which are symmetrically arranged around the axis of the rotor core, and characterized in that:

[0007] The permanent magnet unit includes a central magnet. A central air permanent magnet slot and radial magnets are provided between adjacent permanent magnet units. The central air permanent magnet slot and radial magnets are both arranged on the q-axis, and the central air permanent magnet slot is located inside the radial magnets. The central magnet and the radial magnets on both sides are arranged in a U-shape.

[0008] Furthermore, the coercivity of the radial magnet is lower than that of the central magnet.

[0009] Furthermore, the permanent magnet unit also includes a V-shaped magnet, which is located outside the middle magnet. The V-shaped magnet is composed of two straight magnets, which are respectively arranged on both sides of the d-axis and arranged in a figure-eight shape with the narrow opening facing inward. An inner air permanent magnet groove is provided at the narrow opening of the figure-eight shape, and an outer air permanent magnet groove is provided at the outer end of each of the two straight magnets.

[0010] Furthermore, the coercivity of the two straight magnets that make up the V-shaped magnet is higher than that of the radial magnet.

[0011] The built-in tangential hybrid magnet-focusing permanent magnet rotor provided by this utility model adopts a U-shaped arrangement of magnets and utilizes multiple sets of magnets for multi-directional magnetization, resulting in a strong magnetizing effect. Moreover, by using magnets with different coercivities, it can effectively suppress armature reaction at both ends of the magnets, thereby improving the motor's overload capacity and overload multiple. The air permanent magnet slot (non-magnetic flux barrier) plays a role in magnetic isolation and suppressing leakage flux. The multi-layer permanent magnet structure, with radial, tangential, and high- and low-energy magnets mixed for multi-path magnetization, makes the radial force of the d-axis of the magnetic pole radial centerline and the q-axis of the inter-pole centerline tend to be balanced, which can improve the air gap magnetic flux density, thereby improving torque density and power density, and reducing motor noise and torque fluctuation. Attached Figure Description

[0012] Figure 1 This is a radial cross-sectional schematic diagram of the built-in tangential hybrid magnet concentrated permanent magnet rotor of the first embodiment of this utility model;

[0013] Figure 2 This is a radial cross-sectional schematic diagram of the built-in tangential hybrid magnet concentrated permanent magnet rotor of the second embodiment of this utility model. Detailed Implementation

[0014] The embodiments of this utility model are described in further detail below with reference to the accompanying drawings. However, these embodiments are not intended to limit this utility model. Any similar structures or variations thereof that adopt this utility model should be included in the protection scope of this utility model. The commas in this utility model all indicate the relationship between and.

[0015] like Figure 1As shown, the first embodiment of this utility model provides a built-in tangential hybrid magnet type permanent magnet rotor, including a rotor core 11 and a rotating shaft 12. The rotor core 11 is provided with multiple permanent magnet units symmetrically arranged around the axis of the rotor core. Its characteristic is that:

[0016] The permanent magnet unit includes a central magnet 143. A central air permanent magnet slot 142 and radial magnets 141 are provided between adjacent permanent magnet units. The central air permanent magnet slot 142 and radial magnets 141 are both arranged on the q-axis. The central air permanent magnet slot 142 is located inside the radial magnets 141 (the side facing the rotor core axis is the inner side). The central magnet 143 and the radial magnets 141 on both sides are arranged in a U-shape. The part of the rotor core 11 that is surrounded by the central magnet 143 and the radial magnets 141 constitutes the pole shoe 13.

[0017] The coercivity of the radial magnet 141 is lower than that of the central magnet 143. The radial magnet 141 is made of a low-coercivity ferrite material, while the central magnet 143 is made of a high-coercivity neodymium iron boron material.

[0018] like Figure 2 As shown, the second embodiment of this utility model is similar to the first embodiment. The second embodiment also includes a rotor core 21 and a rotating shaft 22. The rotor core 21 is also provided with a plurality of permanent magnet units symmetrically arranged around the axis of the rotor core. The permanent magnet unit includes a central magnet 243. A central air permanent magnet slot 242 and a radial magnet 241 are provided between adjacent permanent magnet units. The central air permanent magnet slot 242 and the radial magnet 241 are both arranged on the q-axis. The central air permanent magnet slot 242 is arranged inside the radial magnet 241. The central magnet 243 and the radial magnets 241 adjacent to it on both sides are arranged in a U-shape.

[0019] The coercivity of the radial magnet 241 is lower than that of the central magnet 243. The radial magnet 241 is made of a low-coercivity ferrite material, while the central magnet 243 is made of a high-coercivity neodymium iron boron material.

[0020] The difference between the second embodiment and the first embodiment of this utility model is that the permanent magnet unit further includes a V-shaped magnet. The V-shaped magnet is located outside the central magnet 243. The V-shaped magnet is composed of two straight magnets 251. The two straight magnets 251 are respectively arranged on both sides of the d-axis and are arranged in a figure-eight shape with the narrow opening facing inward. An inner air permanent magnet groove 252 is provided in the narrow opening of the figure-eight shape. An outer air permanent magnet groove 253 is provided at the outer end of each of the two straight magnets 251. The coercivity of the two straight magnets 251 is higher than that of the radial magnet 241. Both straight magnets 251 are made of neodymium iron boron material with high coercivity. The part of the rotor core 21 surrounded by the two straight magnets 251 constitutes the pole shoe 23.

[0021] The motor with the permanent magnet rotor of the embodiment is compared with the motor with the existing built-in double-layer U-shaped permanent magnet rotor of the same specification, and the parameters of the motor with the existing built-in double-layer U-shaped permanent magnet rotor are as follows: the rated power is 36KW, the rated current is 109A, the efficiency is 94.2%, the rated rotating speed is 3000r / min, the maximum rotating speed is 9000r / min, the rated torque is 115Nm, and the maximum torque is 253Nm;

[0022] Compared with the motor with the existing built-in double-layer U-shaped permanent magnet rotor of the same specification, the motor with the permanent magnet rotor of the first embodiment of the utility model has the rated current reduced from 109A to 102A, the efficiency increased from 94.2% to 96.5%, the rated power increased from 36KW to 38KW, the rated torque increased from 115Nm to 121Nm, and the maximum torque increased from 253Nm to 268Nm, that is, the power density and the torque density are both significantly improved.

[0023] Compared with the motor with the existing built-in double-layer U-shaped permanent magnet rotor of the same specification, the motor with the permanent magnet rotor of the second embodiment of the utility model has the efficiency increased from 94.2% to 97.2%, the rated power increased from 36KW to 38KW, and the rated torque increased from 115Nm to 121Nm under the condition that the rated current is reduced from 109A to 121A, that is, the power density and the torque density are both significantly improved.

[0024] Therefore, the first embodiment and the second embodiment of the utility model both improve the air gap flux density waveform, reduce the motor noise and torque fluctuation by improving the power density and the torque density.

Claims

1. A built-in tangential mixed magnetic steel magnetic type permanent magnet rotor, comprising a rotor core and a rotating shaft, the rotor core is provided with a plurality of permanent magnet units arranged symmetrically around the axis of the rotor core, characterized in that: the permanent magnet unit comprises a middle magnetic steel, and a middle air permanent magnet slot and a radial magnetic steel are arranged between adjacent permanent magnet units, the middle air permanent magnet slot and the radial magnetic steel are arranged on the q-axis, and the middle air permanent magnet slot is arranged inside the radial magnetic steel, and the middle magnetic steel and the radial magnetic steels on both sides thereof are arranged in a U shape. The coercive force of the radial magnetic steel is lower than that of the middle magnetic steel.

2. The built-in tangential hybrid mixed magnetic steel magnetically-polymerized permanent magnet rotor according to claim 1, characterized in that: The permanent magnet unit further comprises a V-shaped magnetic steel, the V-shaped magnetic steel is located outside the middle magnetic steel, the V-shaped magnetic steel is composed of two linear magnetic steels, the two linear magnetic steels are arranged on both sides of the d-axis and are arranged in a figure-eight shape with the narrow opening facing inward, and an inner end air permanent magnet slot is arranged at the narrow opening of the figure-eight shape, and each outer end of the two linear magnetic steels is provided with an outer end air permanent magnet slot.

3. The built-in tangential mixing magnetic steel magnetic type permanent magnet rotor according to claim 1 or 2, characterized in that: The coercive force of the two linear magnetic steels constituting the V-shaped magnetic steel is higher than that of the radial magnetic steel.

4. The built-in tangential hybrid mixed magnetic steel magnetic type permanent magnet rotor according to claim 3, characterized in that: ​

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