Asymmetrical Rotor Flow Barriers for Low Torque Ripple Motors
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Solution Overview
Problem
Synchronous reluctance electrical machines with permanent magnets face issues of torque ripples and counter-electromotive force harmonics, leading to rotor vibrations and high losses, which are exacerbated by the need for small air gaps that increase costs and precision requirements.
Innovation Solution
A rotor design with a lamellar pack comprising sheets with axial recesses and magnetic flow generators, featuring asymmetrical flow barriers that reduce torque ripple and counter-electromotive force harmonics, allowing for a larger air gap and increased working tolerances, comprising eight magnetic poles with three flow barriers each, and specific opening angles to optimize magnetic flux distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the air gap between rotor and stator is reduced to improve electrical machine performance, then efficiency and performance are improved, but manufacturing precision requirements and costs increase
Solution Approach 1:
The patent applies asymmetry by designing flow barriers with different configurations in alternating poles. Specifically, in poles of the same magnetic polarity, adjacent flow barriers have different opening angles relative to the radial direction, creating an asymmetric magnetic flux distribution that reduces torque ripples and allows for larger air gaps without sacrificing performance
2Ease of manufacture
If the air gap between rotor and stator is increased to reduce manufacturing costs and tolerances, then working tolerances and costs are improved, but electrical machine performance deteriorates
Solution Approach 1:
The patent changes the geometric parameters of the flow barriers, specifically the opening angles, to optimize magnetic flux distribution. By adjusting these parameters, the invention maintains strong magnetic coupling across the air gap even when the air gap itself is enlarged, thereby preserving performance while improving manufacturability
3Device complexity
If conventional rotor design is used, then结构简单 is maintained, but torque ripple and counter-electromotive force harmonics increase
Solution Approach 1:
The patent introduces asymmetry in the flow barrier design where alternating poles have flow barriers with different opening angles. This asymmetric configuration modifies the magnetic flux distribution in a controlled manner, effectively reducing torque ripples and counter-electromotive force harmonics while maintaining reasonable structural complexity
Solution Approach 2:
The rotor is segmented into multiple poles with alternating flow barrier configurations. Each pole contains multiple flow barriers with specific opening angles, creating a segmented approach to flux control that reduces harmful harmonics through distributed magnetic field modification
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 rotor design enhances efficiency and performance by minimizing torque ripple and counter-electromotive force harmonics, enabling a larger air gap that reduces costs and increases working tolerances, while maintaining high performance.
Implementation Method 1
specific opening angles to optimize magnetic flux distribution
Implementation Method 2
The rotor is rotated by reluctance torque and magnet torque
Implementation Method 3
The rotor is rotated by reluctance torque and magnet torque
Implementation Method 4
electric coils adapted to generate a magnetic field which allows rotating the rotor
Data Source
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AI summary
A rotor (1) for electrical machine is described, comprising a rotation shaft; a lamellar pack comprising a plurality of sheets (3), comprising a number (Pp) of pairs of primary magnetic poles (13) and secondary magnetic poles (14), each of the primary magnetic poles (13) and secondary magnetic poles (14) comprising an internal flow barrier (11), an intermediate flow barrier (10), and an external flow barrier (9).