Stator Tooth Geometry for Torque Ripple Reduction
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Solution Overview
Problem
Conventional rotating electric machines experience vibrations and noise due to the difference in magnetic flux flow states between inter-hetero-phase and inter-homo-phase teeth, leading to varying magnetic reluctance and torque ripples.
Innovation Solution
The design includes an annularly-shaped stator core with specific geometry for stator teeth, where inter-hetero-phase teeth have a longer magnetic flux path length and tapered structures to match the reluctance of inter-homo-phase teeth, reducing torque variations and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stator teeth are used with uniform structure, then manufacturing is simple, but magnetic flux flow states differ between inter-hetero-phase and inter-homo-phase teeth causing torque ripples and vibrations
Solution Approach 1:
The patent applies local quality by giving different structures to different types of stator teeth. Specifically, inter-hetero-phase teeth are designed with a first structure (including a first protrusion and first recess) while inter-homo-phase teeth are designed with a second structure (including a second protrusion and second recess). This local differentiation allows each tooth type to optimize its magnetic flux flow characteristics for its specific position, thereby reducing torque ripples and vibrations caused by uniform structure limitations.
2Reliability
If magnetic flux path length is not adjusted, then stator tooth structure is simple, but magnetic reluctance varies between inter-hetero-phase and inter-homo-phase teeth causing torque variations
Solution Approach 1:
The patent applies parameter changes by specifically adjusting the magnetic flux path length in inter-hetero-phase teeth. The first protrusion and first recess are designed to create a longer magnetic flux path length compared to the second protrusion and second recess in inter-homo-phase teeth. This parameter adjustment equalizes the magnetic reluctance across different tooth types, stabilizing torque output and reducing variations.
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 configuration reduces vibrations and noise by stabilizing magnetic reluctance and torque, ensuring smoother operation of the rotating electric machine.
Implementation Method 1
a multiphase coil attached to the stator core and including a plurality of phase coils supplied with alternating currents of different phases respectively, and a rotor inserted in the stator and having a plurality of magnetic poles
Implementation Method 2
a magnetic flux is generated from each phase coil when alternating current is supplied to the phase coil
Data Source
AI summary
In a rotating electric machine, a path length between a rotor and an inter-hetero-phase tooth where a magnetic flux from a magnetic pole proceeds from the rotor and starts to enter the inter-hetero-phase tooth is longer than a path length between the rotor and an inter-V-phase tooth where the magnetic flux proceeds from the rotor and starts to enter the inter-V-phase tooth.