Rotor Core Auxiliary Groove Configuration for Torque Ripple Reduction
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Solution Overview
Problem
Existing step-skewing motors and permanent magnet synchronous motors experience torque ripple and radial electromagnetic forces due to stator slotting and magnetic saturation, leading to noise and vibration issues, particularly in applications like new energy vehicles, where NVH quality is critical.
Innovation Solution
A rotor core with staggered segments and auxiliary grooves of varying positions and shapes across the rotor core segments, optimized by rotating each segment to offset groove centers and adjust groove shapes, effectively dispersing harmonic energy and reducing torque ripple and vibration noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If rotor skewing and auxiliary grooves are used to reduce torque ripple and radial electromagnetic forces, then vibration and noise are reduced, but the comprehensive vibration and noise reduction effect is not optimal when all segments use the same punching piece structure
Solution Approach 1:
The patent applies local quality by making each rotor core segment have different auxiliary groove configurations (different positions, cross-sectional shapes, or both) while maintaining the overall rotor structure. This localized differentiation allows each segment to optimally suppress specific harmonic components of radial electromagnetic forces, achieving better comprehensive vibration and noise reduction compared to uniform segment structures.
Solution Approach 2:
The rotor core is divided into multiple segments with different punching piece structures. Each segment can be independently designed with specific auxiliary groove characteristics, allowing the system to address different frequency components of vibration and noise through segmented optimization rather than treating the entire rotor as a single uniform structure.
2Object-affected harmful factors
If auxiliary grooves with varying positions and shapes are implemented across rotor core segments, then torque ripple and radial electromagnetic forces are suppressed, but manufacturing complexity increases
Solution Approach 1:
The patent implements local quality by configuring different auxiliary grooves in different rotor core segments. Each segment's punching piece is designed with specific groove positions and shapes tailored to suppress particular harmonic orders of radial electromagnetic forces. This localized customization targets specific vibration sources while maintaining manufacturing feasibility through standardized production processes for each segment type.
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 significantly suppresses torque ripple and radial electromagnetic forces, resulting in improved vibration and noise reduction, enhancing the overall NVH quality of the motor.
Implementation Method 1
effectively dispersing harmonic energy and reducing torque ripple and vibration noise
Implementation Method 2
suppress torque ripple and vibration noise when the motor rotates
Data Source
AI summary
A rotor core is provided for a step-skewing motor that includes rotor core segments mutually staggered by a preset angle. Each of the rotor core segments includes magnet slots along a circumferential direction, with a magnet provided in the magnet slot. An outer circular surface of each of the rotor core segments is provided thereon with a number of auxiliary grooves extending across the segment in an axial direction, and positions and/or cross-sectional shapes of the auxiliary grooves on the rotor core segments are not completely same so as to suppress torque ripple and vibration noise when the motor rotates.