Rotary Electrical Machine Stator Winding Torque Ripple Reduction
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Solution Overview
Problem
Rotating electrical machines in electric vehicles generate significant noise due to torque ripple, which is not effectively addressed by existing technologies.
Innovation Solution
The design incorporates a stator winding with a wave winding pattern and specific slot conductor arrangements, where cross conductors connect slot conductors across slots with varying pitch settings to reduce torque ripple and noise, ensuring no phase difference between voltages induced in stator winding groups, and slot conductors are positioned to minimize harmonic components in the induced voltage and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional winding technologies are used in rotating electrical machines, then the machine can operate, but significant noise is generated due to torque ripple
Solution Approach 1:
The patent applies parameter changes by modifying the winding configuration parameters, specifically using a wave winding pattern with cross conductors connecting slot conductors at specific pitch intervals (Np = N + 1 and Np = N - 1). This changes the electrical parameters of the winding to reduce harmonic components in the induced voltage and torque, thereby reducing noise while maintaining reliable operation
Solution Approach 2:
The patent applies local quality by creating different winding arrangements in different parts of the stator winding. The cross conductors connect slot conductors with different pitch relationships (N + 1 on one side, N - 1 on the other side), creating localized variations in the magnetic field distribution that collectively reduce overall torque ripple and noise
2Object-affected harmful factors
If slot conductors are arranged in conventional patterns, then the winding structure is simple, but higher harmonic components in induced voltage and torque increase noise
Solution Approach 1:
The patent applies segmentation by dividing the stator winding into multiple independent round windings connected in parallel, with each round winding having slot conductors inserted in specific slots. The cross conductors connect these segmented windings with specific pitch relationships, allowing independent optimization of each segment while achieving overall noise reduction through the combined effect
Solution Approach 2:
The patent applies dimensionality change by considering the three-dimensional arrangement of slot conductors in terms of slot positions and layer positions. The cross conductors connect slot conductors not only across different slots but also between different layers, adding a dimensional aspect to the winding configuration that enables more effective harmonic cancellation
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 significantly reduces noise and torque ripple in rotating electrical machines, enhancing their performance and suitability for electric vehicles by minimizing higher harmonic components in induced voltages and torque.
Implementation Method 1
a stator winding assuming a plurality of phases, which includes a plurality of round windings wound with a wave winding pattern
Implementation Method 2
a rotor rotatably supported with an air gap so as to be allowed to rotate relative to the stator core
Data Source
Figure 1
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AI summary
A rotating electrical machine includes: a stator core having a plurality of slots formed therein; a stator winding assuming a plurality of phases, which includes a plurality of round windings wound with a wave winding pattern, each having slot conductors each inserted at one of the slots at the stator core to form one of a plurality of layers and cross conductors each connecting same-side ends of slot conductors inserted at different slots so as to form a coil end; and a rotor rotatably supported with an air gap so as to be allowed to rotate relative to the stator core, wherein: the cross conductors connect the slot conductors so as to run astride slots with the slot pitch Np set to N + 1 at coil ends on one side and run astride slots with the slot pitch Np set to N - 1 at coil ends on another side, with N representing a number of slots per pole; the stator winding includes a plurality of slot conductor groups each having a plurality of slot conductors corresponding to a single phase; the plurality of slot conductors in each slot conductor group are inserted at a predetermined number Ns of successive slots forming a continuous range along a circumference of the stator core so that the slot conductors in the slot conductor group take successive slot positions and successive layer positions; and the predetermined number Ns is set so that Ns = NSPP + NL when NSPP represents a number of slots per phase per pole and a number of layers is expressed as 2 x NL.