Interior Permanent Magnet Motor Notch Design for Cogging Torque Reduction
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Solution Overview
Problem
Internal permanent magnet motors generate cogging torque due to magnetic field interactions, leading to noise, vibration, and harshness issues in eco-friendly vehicles, affecting their marketability and controllability.
Innovation Solution
The motor design incorporates notches on both the stator and rotor surfaces, with specific dimensions and angles to optimize the notch structure, reducing cogging torque by altering the magnetic field interactions and mechanical resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If notches are formed on the stator and rotor to reduce cogging torque, then noise and vibration are reduced, but the structural complexity increases
Solution Approach 1:
The patent applies local quality by forming notches only in specific regions where the stator and rotor face each other, rather than modifying the entire structure. The notches are strategically positioned at the interfaces between stator teeth and rotor permanent magnets, creating localized geometric changes that reduce cogging torque while preserving the overall structural integrity and simplicity of the motor design.
2Ease of operation
If the notch depth and width are increased to reduce cogging torque, then controllability improves, but the mechanical strength decreases
Solution Approach 1:
The patent employs parameter changes by optimizing the depth and width of the notches to specific ranges that balance cogging torque reduction with mechanical strength preservation. The notch depth is controlled to be within a specific range relative to the stator tooth height, and the width is optimized relative to the stator tooth width, ensuring that the notches are sufficient to reduce cogging torque and improve controllability while maintaining the structural strength required for reliable operation.
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
Significantly reduces cogging torque, improving noise, vibration, and harshness performance, enhancing motor controllability and reducing vibrations in sensitive driving conditions.
Implementation Method 1
an internal permanent magnet motor configured for reducing a cogging torque by forming a notch in a region in which a stator and a rotor face to each other
Implementation Method 2
The internal permanent magnet motor generates a cogging torque due to a change in reluctance in a circumferential direction resulting from a magnetic field of the permanent magnet provided at the rotor
Data Source
AI summary
An internal permanent magnet motor may include a stator of a annular shape, and a rotor coaxially disposed inside the stator by positioned between a gap between the rotor and the stator and having a plurality of permanent magnets embedded therein and spaced from each other in a circumferential direction along a circumference of the rotor, wherein the stator has a plurality of first notches formed on an internal circumferential surface facing the rotor in a height direction perpendicular to the circumferential direction thereof, and the rotor has a plurality of second notches formed on an external circumferential surface facing the stator in a height direction perpendicular to the circumferential direction thereof.