Built-in multi-layer arc-shaped mixed magnetic steel magnetism gathering type permanent magnet rotor
By designing a built-in multi-layer arc-shaped hybrid magnet permanent magnet rotor, the problems of torque fluctuation and low power density of existing built-in permanent magnet synchronous motors are solved, achieving higher torque density and power density, reducing noise and expanding the constant power speed range of the motor.
Patent Information
- Application Number
- CN202520033225.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Priority Date
- 2024-12-30
- Filing Date
- 2025-01-07
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2035-01-07
AI Technical Summary
Existing built-in permanent magnet synchronous motors suffer from problems such as large torque fluctuations, low power and torque density, low overload capacity, and poor reliability, making it difficult to simultaneously improve air gap magnetic flux density and ensure the safety of high-speed motor operation.
The rotor adopts a built-in multi-layer arc-shaped hybrid magnet with a magnetizing permanent magnet. Through the segmented arrangement of three-layer arc-shaped magnet groups and the design of air permanent magnet slots, multiple air magnetic barriers are formed. Combined with the use of high and low coercivity magnets, the air gap magnetic flux density and magnetic reluctance torque ratio are improved. The width of the magnetic guide bridge is adjusted to control magnetic circuit saturation, thereby achieving multi-path magnetization and magnetic pole force balance.
It significantly improves torque density and power density, reduces motor noise and torque fluctuation, expands the constant power speed range, and enhances motor reliability and starting capability.
Smart Images
Figure CN223729526U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to motor technical field, especially a kind of built-in multi-layer arc type 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 the 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 the outer edge of rotor, 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 problem to provide a built-in multi-layer arc type mixed magnetic steel magnetic type permanent magnet rotor which can improve air gap flux density, thereby improving torque density and power density, reducing motor noise and torque fluctuation.
[0006] In order to solve the above technical problem, the utility model provides a built-in multi-layer arc type mixed magnetic steel magnetic type permanent magnet rotor, which comprises a rotor core, a plurality of permanent magnet units are arranged on the rotor core, each permanent magnet unit is arranged symmetrically around the axis of the rotor core, characterized in that:
[0007] The permanent magnet unit includes three arc-shaped magnet groups, which are arranged sequentially from the inside to the outside along the radial direction of the rotor. The two ends of the three arc-shaped magnet groups face outward, and each end of the arc-shaped magnet group is provided with a first air permanent magnet slot. The arc-shaped magnet groups are divided into left magnet, middle magnet and right magnet from left to right. A second air permanent magnet slot is provided between the middle magnet and the left magnet and the right magnet.
[0008] The coercivity of the left and right magnets is greater than that of the middle magnet.
[0009] This utility model provides a built-in multi-layer arc-shaped hybrid magnet permanent magnet rotor, which adopts a three-layer segmented arc-shaped arrangement of magnets. Utilizing multiple sets of magnets for multi-directional magnetization, it achieves a strong magnetizing effect. Air permanent magnet slots (non-magnetic flux barriers) form multiple air magnetic barriers at different positions and structures, effectively improving the saliency ratio and reluctance torque ratio. Simultaneously, the use of low-energy-product ferrite magnets enhances the armature magnetic field's ability to weaken and extend speed, significantly reducing centrifugal force during high-speed rotor operation. This facilitates frequent motor starts and provides magnetic isolation and suppression of leakage flux. The magnet groups form a magnetic bridge with the rotor's outer edge. By adjusting the width of the magnetic bridge, the magnetic circuit saturation level is changed, achieving a constant power speed extension effect in the high-speed range, resulting in a wider constant power speed range than existing built-in permanent magnet motors. The multi-layer permanent magnet structure and the hybrid high- and low-energy magnets with multi-path magnetization balance the radial forces along the d-axis of the magnetic pole radial centerline and the q-axis of the inter-pole centerline, increasing the air gap magnetic flux density, thereby improving torque and power density and reducing motor noise and torque fluctuations. Attached Figure Description
[0010] Figure 1 This is a radial cross-sectional schematic diagram of the built-in multi-layer arc-shaped hybrid magnet concentrated permanent magnet rotor according to an embodiment of the present invention. Detailed Implementation
[0011] 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.
[0012] like Figure 1 As shown in the figure, the present invention provides a built-in multi-layer arc-shaped hybrid magnet permanent magnet rotor, comprising a rotor core 1, wherein the rotor core 1 is provided with a plurality of permanent magnet units, and the permanent magnet units are symmetrically arranged around the axis of the rotor core 1. The invention is characterized in that:
[0013] The permanent magnet unit comprises three arc-shaped magnet steel groups, and the three arc-shaped magnet steel groups are arranged from inside to outside along the radial direction of the rotor, two ends of the three arc-shaped magnet steel groups are outward, and the two ends of the arc-shaped magnet steel group are provided with first air permanent magnet grooves 31, the arc-shaped magnet steel group is divided into a left magnet steel 21, a middle magnet steel 22 and a right magnet steel 23 from left to right, and the middle magnet steel 22 is provided with a second air permanent magnet groove 32 between the left magnet steel 21 and the right magnet steel 23.
[0014] The coercive force of the left magnet steel 21 and the right magnet steel 23 is greater than the coercive force of the middle magnet steel 22.
[0015] The motor adopting the permanent magnet rotor of the embodiment is compared with the motor of the same specification adopting the existing built-in double-layer U-shaped permanent magnet rotor, the parameters of the motor of 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 speed is 3000r / min, the maximum speed is 9000r / min, the rated torque is 115Nm, and the maximum torque is 253Nm.
[0016] Compared with the motor of the same specification of the existing built-in double-layer U-shaped permanent magnet rotor, the motor adopting the permanent magnet rotor of the embodiment has the rated current reduced from 109A to 102A, the efficiency increased from 94.2% to 96.3%, 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 significantly improved.
[0017] Therefore, the embodiment of the utility model improves the air gap flux density waveform, reduces the motor noise and torque fluctuation by improving the power density and torque density.
Claims
1. A built-in multi-layer arc-shaped hybrid magnetic steel magnetic gathering type permanent magnet rotor, comprising a rotor core, a plurality of permanent magnet units are arranged on the rotor core, and each permanent magnet unit is arranged symmetrically around the axis of the rotor core, characterized in that: the permanent magnet unit comprises three arc-shaped magnetic steel groups, and the three arc-shaped magnetic steel groups are arranged from inside to outside along the radial direction of the rotor, the two ends of the three arc-shaped magnetic steel groups are outward, and the two ends of the arc-shaped magnetic steel group are provided with first air permanent magnet grooves, the arc-shaped magnetic steel group is divided into left magnetic steel, middle magnetic steel and right magnetic steel from left to right, and the middle magnetic steel is provided with second air permanent magnet grooves between the left magnetic steel and the right magnetic steel. The coercive force of the left magnetic steel and the right magnetic steel is greater than the coercive force of the middle magnetic steel.