Rotary Electric Machine Winding Pattern for Torque Ripple Reduction
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Solution Overview
Problem
Rotary electric machines in electric vehicles face challenges in achieving high torque and low noise simultaneously due to existing winding configurations that do not effectively manage torque ripple and noise levels.
Innovation Solution
The rotary electric machine design incorporates a stator core with wave-wound winding coils and jumper conductors that connect slot conductors across slots with specific pitch variations, allowing for a combination of normal and irregular slot pitches to reduce torque ripple and noise, while maintaining high torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional winding configurations are used, then the structure is simple and easy to manufacture, but torque ripple and noise levels increase
Solution Approach 1:
The patent applies local quality by varying the slot pitch in specific regions of the winding configuration. Different slot pitches (Np=N and Np=N+1) are used in different coil ends to locally optimize the magnetic field distribution, reducing torque ripple and noise while maintaining overall winding functionality.
Solution Approach 2:
The patent introduces asymmetry by using different slot pitch relationships in the two coil ends of the winding. One coil end uses slot pitch Np=N while the other uses Np=N+1, creating an asymmetric winding pattern that balances magnetic forces and reduces torque ripple without requiring complete redesign of the entire winding system.
2Object-affected harmful factors
If irregular slot pitch windings are used, then torque ripple is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the slot pitch parameter from a uniform value to two distinct values (N and N+1) in different coil ends. This parameter variation allows torque ripple reduction while the changes are implemented in discrete, manageable increments that can be accommodated by standard manufacturing tolerances.
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 results in a rotary electric machine that provides higher average torque with reduced torque ripple and noise, enhancing the performance of electric vehicles by optimizing winding patterns.
Implementation Method 1
stator windings of a plurality of phases provided with a plurality of wave-wound winding coils, each having a slot conductor inserted into each slot of the stator core and included in any one of a plurality of layers and a jumper conductor that connects the same side ends of the slot conductors inserted into different slots to form a coil end
Data Source
AI summary
A rotary electric machine includes a rotor, a stator, and stator windings. The stator winding has a plurality of slot conductor groups having a plurality of slot conductors of the same phase. A plurality of slot conductors of the slot conductor group are inserted into a predetermined number (Ns) of slots continuously arranged in a circumferential direction of the stator core such that the slot and the layer are adjacent to each other. The predetermined number (Ns) is set to “Ns=NSPP+1,” where “NSPP” denotes the number of slots per pole per phase.