Asymmetrical V-Barrier Rotor for Low-Harmonic Reluctance Machines
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Solution Overview
Problem
Synchronous reluctance electrical machines with permanent magnets face issues with 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 reduce working tolerances.
Innovation Solution
A rotor design featuring a lamellar pack with axial recesses and embedded permanent magnets, along with asymmetrical flow barriers forming a 'V' shape, which reduces torque ripple and counter-electromotive force harmonics, allowing for a larger air gap and increased working tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the air gap between rotor and stator is reduced to improve machine performance, then efficiency and performance are improved, but manufacturing precision requirements increase and working tolerances decrease
Solution Approach 1:
The patent introduces asymmetrical flow barriers with a 'V' shape configuration where the two branches of the V have different angles relative to the radial direction. This asymmetrical design creates specific magnetic flux distribution patterns that reduce torque ripples and harmonics, thereby improving machine performance while allowing for larger air gaps and relaxed manufacturing tolerances
Solution Approach 2:
The patent modifies the geometric parameters of the flow barriers by defining specific angle ranges for the V-shaped branches (first branch angle α between 10°-30° and second branch angle β between 30°-50°). By optimizing these angular parameters, the magnetic flux distribution is controlled to minimize harmful harmonics, enabling the machine to achieve high performance with larger air gaps
2Power
If permanent magnets are embedded in the rotor to improve performance, then machine performance is improved, but torque ripples and counter-electromotive force harmonics increase causing vibrations and losses
Solution Approach 1:
The patent converts the harmful magnetic flux paths that would normally cause torque ripples and harmonics into beneficial patterns by introducing asymmetrical flow barriers. These barriers strategically redirect and shape the magnetic flux, transforming what would be disruptive harmonics into controlled flux distribution that improves overall machine performance while reducing vibrations and losses
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 design enhances efficiency and performance by minimizing torque ripple and counter-electromotive force harmonics, enabling higher working tolerances and lower costs while maintaining better machine performance with a larger air gap.
Implementation Method 1
the sheets comprise seats for the permanent magnets
Implementation Method 2
electric coils adapted to generate a magnetic field which allows rotating the rotor
Implementation Method 3
asymmetrical flow barriers forming a 'V' shape, which reduces torque ripple and counter-electromotive force harmonics
Data Source
Figure 1
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Figure 3
AI summary
A rotor (1) for electrical machine is described, comprising a rotation shaft; a lamellar pack comprising a plurality of sheets (3), comprising three 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).