Rotor Structure with Radial Magnet Segments for Ferrite Motors
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Solution Overview
Problem
Existing electric vehicle motors face challenges with high production costs due to rare earth permanent magnets, noise issues, demagnetization, and low efficiency, particularly in ferrite permanent magnet auxiliary synchronous reluctance motors.
Innovation Solution
A rotor structure with a permanent magnet slot group featuring permanent magnet segments of varying lengths arranged radially, including inner and outer layers with curved segments and magnetic barriers, and buffer structures to reduce eddy current loss, torque ripple, and noise, while enhancing anti-demagnetization capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ferrite permanent magnet auxiliary synchronous reluctance motors are used, then cost is reduced, but efficiency and power density decrease
Solution Approach 1:
The patent applies local quality by creating non-uniform permanent magnet segment lengths arranged radially, where inner layer segments have different lengths than outer layer segments. This localized variation optimizes magnetic field distribution in different radial zones, improving motor efficiency while maintaining ferrite material cost-effectiveness
Solution Approach 2:
The patent uses composite material strategy by combining ferrite permanent magnets with auxiliary synchronous reluctance motor structure. The multi-layer permanent magnet configuration (inner and outer layers with varying segment lengths) creates a composite magnetic circuit that enhances overall motor performance beyond what single-material motors achieve
2Productivity
If rare earth permanent magnets are used, then motor efficiency and power density increase, but production cost increases
Solution Approach 1:
The patent replaces expensive rare earth permanent magnets with cheaper ferrite permanent magnets. While ferrite has lower intrinsic magnetic properties, the innovative multi-layer segment structure compensates for this, achieving acceptable efficiency at reduced material cost
3Ease of manufacture
If traditional permanent magnet slots are used, then manufacturing is simple, but eddy current loss and torque ripple increase
Solution Approach 1:
The patent applies segmentation by dividing permanent magnets into multiple segments arranged in inner and outer layers with varying lengths. This segmentation disrupts eddy current paths, reducing eddy current losses and torque ripple while maintaining manufacturing feasibility through modular assembly
Solution Approach 2:
The patent introduces radial dimension variation by arranging permanent magnet segments at different radial positions with different lengths. This multi-dimensional configuration optimizes magnetic flux distribution and reduces electromagnetic losses compared to traditional uniform slot designs
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
The solution effectively reduces eddy current loss, increases inductance, decreases motor vibration and noise, and improves efficiency and anti-demagnetization performance, leading to a more cost-effective and efficient motor design.
Implementation Method 1
a permanent magnet arranged in the permanent magnet slot, the permanent magnet including a plurality of permanent magnet segments, and partial lengths of the permanent magnet segments gradually decreasing outwards along a radial direction of the rotor body
Implementation Method 2
partial lengths of the permanent magnet segments gradually decreasing outwards along a radial direction of the rotor body
Data Source
AI summary
Rotor structure, permanent magnet auxiliary synchronous reluctance motor and electric vehicle. The rotor structure includes: a rotor body provided with a permanent magnet slot group, the permanent magnet slot group including a permanent magnet slot, a first segment and a second segment of the permanent magnet slot being arranged to extend towards an outer edge of the rotor body, and an intermediate portion of the permanent magnet slot being arranged to protrude towards a side where a shaft hole of the rotor body is disposed; and a permanent magnet arranged in the permanent magnet slot, the permanent magnet including a plurality of permanent magnet segments, and partial lengths of the permanent magnet segments gradually decreasing outwards along a radial direction of the rotor body.