EV Drive Stator Winding Asymmetry for Low Torque Ripple
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Solution Overview
Problem
Existing electric vehicle drive systems experience torque ripples and parasitic forces, leading to undesirable noise, vibration, and harshness (NVH) behavior, which are challenging to mitigate with symmetrically disposed stator windings in the stator core.
Innovation Solution
The drive equipment is designed with a converter equipment that preferentially sets one rotation direction of the rotor movement, where the second side along this direction succeeds the first side, and each winding zone on the first side occupies a smaller cross-sectional area than on the second side, ensuring symmetric disposition of stator windings in the slots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stator windings are disposed symmetrically in the stator core, then manufacturing ease and production reliability are improved, but torque ripples and parasitic forces increase leading to poor NVH behavior
Solution Approach 1:
The patent applies asymmetry by making the winding zones asymmetric with respect to the stator core centerline. Specifically, the first winding zone has a different cross-sectional area than the second winding zone, creating an asymmetric magnetic field distribution that reduces torque ripples and parasitic forces while improving NVH behavior, thereby resolving the contradiction between symmetrical manufacturing ease and harmful torque ripple effects
2Ease of manufacture
If stator windings are disposed symmetrically in the stator core, then manufacturing ease and production reliability are improved, but NVH behavior deteriorates due to increased torque ripples and parasitic forces
Solution Approach 1:
The patent applies asymmetry by making the winding zones asymmetric with respect to the stator core centerline. Specifically, the first winding zone has a different cross-sectional area than the second winding zone, creating an asymmetric magnetic field distribution that reduces torque ripples and parasitic forces while improving NVH behavior, thereby resolving the contradiction between symmetrical manufacturing ease and harmful torque ripple effects
3Shape
If winding zones occupy equal cross-sectional area in slots, then symmetrical winding disposition is achieved, but torque ripple increases and smooth operation is reduced
Solution Approach 1:
The patent applies asymmetry by making the winding zones asymmetric with respect to the stator core centerline. Specifically, the first winding zone has a different cross-sectional area than the second winding zone, creating an asymmetric magnetic field distribution that reduces torque ripples and parasitic forces while improving NVH behavior, thereby resolving the contradiction between symmetrical manufacturing ease and harmful torque ripple effects
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 achieves low torque ripple and smooth operation, enhancing the NVH behavior by optimizing the winding zone occupation according to the preferred rotation direction, resulting in more efficient transmission and cooling in the preferred direction.
Implementation Method 1
a stator which is configured for generating a magnetic rotating field
Implementation Method 2
a converter equipment for converting magnetic energy of the rotating field into a rotating output movement
Data Source
AI summary
Drive equipment for an electric vehicle is disclosed with a stator which is configured for generating a magnetic rotating field, a stator core in which a multiplicity of slots disposed in the circumferential direction are configured, and a stator winding which occupies a plurality of winding zones in the slots. Each winding zone in a cross-sectional plane that is perpendicular to the longitudinal axis by way of a centric radial division is sub-divided into a first side and a second side. Converter equipment converts magnetic energy of the rotating field into a rotating output movement of the drive equipment. The converter equipment has a rotor which conjointly with the stator forms a rotating electric machine such that the rotor is able to be set in a rotating rotor movement which, as a function of the rotating field, selectively has one of two opposite rotation directions.