Built-in double-layer V-shaped mixed magnetic steel magnetism gathering type permanent magnet rotor
By setting multiple V-shaped magnets and radial magnets on the rotor core of the built-in permanent magnet synchronous motor, combining air permanent magnet slots and magnets with different coercive forces, a multi-layer permanent magnet structure is formed, which solves the problem of difficulty in taking into account power density, torque density and high-speed operation safety in the prior art, achieving higher torque density and power density, and reducing noise and fluctuations.
Patent Information
- Application Number
- CN202510024493.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-12-30
- Filing Date
- 2025-01-07
- Publication Date
- 2025-02-28
AI Technical Summary
When the existing built-in permanent magnet synchronous motor improves the magnetic density of the air gap, it is difficult to take into account the power density, torque density and high-speed operation safety.
A built-in double-layer V-shaped hybrid magnet steel polymagnetic permanent magnet rotor is used. By setting multiple V-shaped magnets and radial magnets on the rotor core, combining air permanent magnet slots and magnets with different coercive forces, a multi-layer permanent magnet structure is formed to improve the air gap magnetic density.
It significantly improves torque density and power density, reduces motor noise and torque fluctuations, and enhances the overload capacity and reliability of the motor.
Smart Images
Figure CN119543496A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of motor technology, and in particular to the technology of a built-in double-layer V-shaped hybrid magnetic steel magnetic concentrating type permanent magnet rotor. Background Art
[0002] Currently, permanent magnet synchronous motors suitable for electric vehicles and industrial automation have defects such as large torque fluctuations, low power and torque density, low overload capacity and poor reliability, which make it difficult to meet the requirements. The drive motors restrict the research and development and industrialization process of China's electric vehicles and industrial automation.
[0003] For a long time, improving power and torque density and reducing motor torque fluctuation have been one of the focuses of motor research at home and abroad. One way to improve power density is to increase the speed, but it is necessary to increase the input power supply voltage frequency, which leads to an increase in high-order harmonics, permanent magnet rotor losses and motor temperature rise; an effective way to improve power density and torque density is to increase the air gap flux and air gap flux density, thereby increasing the no-load back EMF and reducing leakage flux. For this reason, the existing internal permanent magnet synchronous motor (IPMSM) takes two measures to jointly resist leakage flux and improve air gap flux density: 1) Air permanent magnet slots are set at both ends of the internal magnetic steel, that is, non-magnetic flux barriers (Non-magnetic flux barriers), which play a magnetic isolation role and improve air gap flux density; 2) Magnetic isolation bridges are set between the two ends of the permanent magnet poles (q axis) and the outer edge of the rotor to improve the air gap flux density.
[0004] The narrower the magnetic bridge thickness is designed, the deeper the magnetic circuit is saturated, and the smaller the magnetic permeability coefficient is, which can limit the leakage flux, increase the effective magnetic flux, and improve the air gap magnetic density; however, 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 increased, and the service life of the rotor silicon steel sheet 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. At high speed, there is a hidden danger of plastic deformation of the rotor, and the high-speed operation of the motor is unsafe. Therefore, the existing IPMSM, the magnetic bridge is difficult to isolate leakage flux, and it is difficult to balance the power density of the motor by increasing the air gap magnetic density and the safety of the motor's high-speed operation. Summary of the invention
[0005] In view of the defects existing in the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a built-in double-layer V-shaped hybrid magnetic steel magnetic concentrating permanent magnet rotor which can increase the air gap magnetic density, thereby increasing the torque density and power density, and reducing the motor noise and torque fluctuation.
[0006] In order to solve the above technical problems, the present invention provides a built-in double-layer V-shaped hybrid magnetic steel magnetic concentrating permanent magnet rotor, including a rotor core and a rotating shaft, wherein the rotor core is provided with a plurality of V-shaped magnetic steels symmetrically arranged around the axis of the rotor core, wherein the V-shaped magnetic steel is composed of two middle magnetic steels, which are arranged on both sides of the d-axis respectively and are arranged in an eight-shaped shape with a narrow opening facing inward, and an inner end air permanent magnet slot is provided in the narrow opening of the eight-shaped shape, and the portion of the rotor core enclosed by the two middle magnetic steels of the V-shaped magnetic steel constitutes a pole shoe; characterized in that: A radial magnetic steel is provided between adjacent V-shaped magnetic steels, and the radial magnetic steel is arranged on the q axis. A fan-shaped hole is opened on the pole shoe, and the fan-shaped hole is arranged symmetrically with respect to the d axis. Assuming that the distance between the radius edge of the fan-shaped hole and the middle magnetic steel is a, and the distance between the arc edge of the fan-shaped hole and the outer edge of the rotor core is b, then a=b; The coercive force of the radial magnetic steel is lower than the coercive force of the central magnetic steel.
[0007] The built-in double-layer V-shaped hybrid magnetic steel magnetic concentrating permanent magnet rotor provided by the present invention adopts a structure of U-shaped arrangement of magnetic steel and mixed V-shaped arrangement, utilizes multiple groups of magnetic steel for multi-directional magnetization, has a strong magnetic concentrating effect, and utilizes magnetic steel settings with different coercive forces to effectively suppress the armature reaction at both ends of the magnetic steel, thereby improving the overload capacity and overload multiple of the motor. The air permanent magnet slots (non-magnetic flux barriers) play the role of isolating magnetic flux and suppressing leakage magnetic flux. The multi-layer permanent magnet structure and the radial and high- and low-energy magnetic steel mixed multi-path magnetic concentrating make the d-axis radial center line of the magnetic pole and the q-axis radial force of the inter-pole center line tend to be balanced, which can improve the air gap magnetic density, thereby improving the torque density and power density, and reducing the motor noise and torque fluctuation. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 It is a schematic radial cross-sectional view of a built-in double-layer V-shaped hybrid magnetic steel magnetic concentrating permanent magnet rotor according to an embodiment of the present invention. DETAILED DESCRIPTION
[0009] The following is a further detailed description of an embodiment of the present invention in conjunction with the accompanying drawings, but this embodiment is not intended to limit the present invention. All similar structures and similar variations of the present invention should be included in the protection scope of the present invention. The commas in the present invention all represent the relationship of and.
[0010] like Figure 1As shown, an embodiment of the present invention provides a built-in double-layer V-shaped hybrid magnetic steel magnetic concentrating permanent magnet rotor, including a rotor core 11 and a rotating shaft 12, wherein the rotor core 11 is provided with a plurality of V-shaped magnetic steels symmetrically arranged around the axis of the rotor core 11, wherein the V-shaped magnetic steels are composed of two middle magnetic steels 143, which are arranged on both sides of the d-axis respectively and are arranged in an eight-shaped shape with a narrow opening facing inward, and an inner end air permanent magnet slot 142 is provided at the narrow opening of the eight-shaped shape, and the portion of the rotor core 11 enclosed by the two middle magnetic steels 143 of the V-shaped magnetic steels constitutes a pole shoe 13; it is characterized in that: A radial magnetic steel 141 is provided between adjacent V-shaped magnetic steels, and the radial magnetic steel 141 is provided on the q axis. A fan-shaped hole 144 is provided on the pole shoe, and the fan-shaped hole 144 is arranged symmetrically with respect to the d axis. Assuming that the distance between the radius edge of the fan-shaped hole 144 and the middle magnetic steel 143 is a, and the distance between the arc edge of the fan-shaped hole 144 and the outer edge of the rotor core is b, then a=b; The coercive force of the radial magnetic steel 141 is lower than the coercive force of the central magnetic steel 143 . The radial magnetic steel 141 is made of a ferrite material with a low coercive force, and the central magnetic steel 143 is made of a neodymium iron boron material with a high coercive force.
[0011] The motor using the permanent magnet rotor of this embodiment is compared with a motor of the same specification using the existing built-in double-layer U-shaped permanent magnet rotor; The parameters of the existing motor with built-in double-layer U-shaped permanent magnet rotor are: rated power 36KW, rated current 109A, efficiency 94.2%, rated speed 3000r / min, maximum speed 9000r / min, rated torque 115Nm, maximum torque 253Nm; Compared with the existing motor with the same specification of built-in double-layer U-shaped permanent magnet rotor, the motor using the permanent magnet rotor of the embodiment of the present invention has a rated current reduced from 109A to 101A, an efficiency increased from 94.2% to 96.7%, a rated power increased from 36KW to 38KW, a rated torque increased from 115Nm to 121Nm, and a maximum torque increased from 253Nm to 268Nm, that is, the power density and torque density are significantly improved; It can be seen that the embodiments of the present invention improve the air gap magnetic flux density waveform and reduce motor noise and torque fluctuation by increasing power density and torque density.
Claims
1. A built-in double-layer V-shaped hybrid magnetic steel magnetic concentrating permanent magnet rotor, comprising a rotor core and a rotating shaft, wherein the rotor core is provided with a plurality of V-shaped magnetic steels symmetrically arranged around the axis of the rotor core, wherein the V-shaped magnetic steels are composed of two middle magnetic steels, which are arranged on both sides of the d-axis respectively and are arranged in an eight-shaped shape with a narrow opening facing inward, and an inner end air permanent magnet slot is provided at the narrow opening of the eight-shaped shape, and the portion of the rotor core surrounded by the two middle magnetic steels of the V-shaped magnetic steels constitutes a pole shoe; characterized in that: A radial magnetic steel is provided between adjacent V-shaped magnetic steels, and the radial magnetic steel is arranged on the q axis. A fan-shaped hole is opened on the pole shoe, and the fan-shaped hole is arranged symmetrically with respect to the d axis. Assuming that the distance between the radius edge of the fan-shaped hole and the middle magnetic steel is a, and the distance between the arc edge of the fan-shaped hole and the outer edge of the rotor core is b, then a=b; The coercive force of the radial magnetic steel is lower than the coercive force of the central magnetic steel.