PMSM Rotor Structure With Magnetic Isolation for End Flux Leakage
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Solution Overview
Problem
Conventional permanent magnet synchronous motors suffer from magnetic flux leakage at the ends of the rotor, leading to poor utilization of permanent magnets and reduced operational performance.
Innovation Solution
A rotor structure is designed with a first rotor core, a second rotor core with magnetic isolation grooves, and axially magnetized first and second permanent magnets. The first permanent magnet partially covers the magnetic isolation groove when projected onto the end surface of the second rotor core, reducing magnetic flux leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axial magnet steel is added to reduce magnetic flux leakage, then the utilization rate of permanent magnets is improved, but the rotor core becomes saturated and the utilization rate of axial magnet steel decreases
Solution Approach 1:
A non-magnetic isolation groove is introduced as an intermediary element between the axial magnet steel and the rotor core. This groove prevents direct magnetic coupling, allowing the axial magnet steel to generate magnetic field without causing saturation in the rotor core, thus resolving the contradiction between improving magnet utilization and avoiding core saturation
Solution Approach 2:
The rotor structure is segmented into distinct functional zones: the axial magnet steel at the ends, the non-magnetic isolation groove in the middle, and the rotor core. This segmentation allows each component to perform its specific function independently, with the isolation groove acting as a buffer zone that prevents magnetic flux from saturating the rotor core
2Device complexity
If conventional tangential or radial magnetization is used, then the motor structure is simple, but magnetic flux leakage occurs at the ends resulting in poor utilization of permanent magnets
Solution Approach 1:
The patent transitions from conventional tangential or radial magnetization (2D magnetic field distribution) to axial magnetization (3D magnetic field distribution). By adding the axial dimension of magnetization and introducing axial magnet steel at the ends, the magnetic field is distributed more effectively throughout the motor volume, reducing end leakage while maintaining structural simplicity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the utilization rate of the axial magnet steel by reducing saturation in the rotor core, thereby improving the efficiency and torque density of the permanent magnet synchronous motor.
Implementation Method 1
a side of the mounting slot close to a central axis of the second rotor core being provided with magnetic isolation groove
Implementation Method 2
a first permanent magnet, which is axially magnetized... two ends of the second rotor core in an axial direction are respectively provided with the first permanent magnet
Implementation Method 3
reducing a saturation effect of a rotor core caused by axial magnet steel
Data Source
AI summary
A rotor structure includes: a first rotor core; a second rotor core being provided a plurality of mounting slots at intervals in a circumferential direction, a side of the plurality of mounting slots close to a central axis of the second rotor core being provided with a magnetic isolation groove; first permanent magnets axially magnetized; and a plurality of second permanent magnets mounted in the plurality of mounting slots in one-to-one correspondence. Two ends of the second rotor core in an axial direction are respectively provided with the first permanent magnets, and a side of the first permanent magnet away from the second rotor core in the axial direction is provided with the first rotor core. In the axial direction, a projection of the first permanent magnet is constructed to partially cover a projection of the magnetic isolation groove.