Two-Layer V-Magnet Rotor Layout for Lower Torque Pulsation
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Solution Overview
Problem
Interior-permanent-magnet synchronous rotary electric machines experience torque pulsation due to leakage magnetic flux, leading to increased vibration and noise, as existing configurations do not adequately consider the harmonic components of the rotor magnetomotive force.
Innovation Solution
A rotary electric machine design featuring a rotor with magnet slots arranged in a V shape in a two-layer structure, where the first-layer effective magnetic flux is not greater than half the second-layer effective magnetic flux, reducing harmonic components of the rotor magnetomotive force and suppressing torque pulsation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If permanent magnets are arranged in two layers in the rotor core, then reluctance torque and magnet torque are increased, but torque pulsation increases due to leakage magnetic flux and harmonic components
Solution Approach 1:
The patent applies local quality by differentiating the magnet widths in the two layers. The inner-layer magnets have a first width while the outer-layer magnets have a second width that is smaller than the first width. This local differentiation optimizes the magnetic flux distribution in different radial zones, reducing leakage flux and harmonic components while maintaining high torque output.
Solution Approach 2:
The patent changes the geometric parameters of the permanent magnets, specifically the width parameter. By setting the outer-layer magnet width to be smaller than the inner-layer magnet width, the patent optimizes the magnetic flux density distribution and reduces the harmonic components that cause torque pulsation, while still achieving high reluctance torque and magnet torque.
2Power
If magnets are arranged in multiple layers, then torque is improved through increased magnet torque and reluctance torque, but vibration and noise increase due to torque pulsation
Solution Approach 1:
The patent applies local quality by differentiating the magnet widths in the two layers. The inner-layer magnets have a first width while the outer-layer magnets have a second width that is smaller than the first width. This local differentiation optimizes the magnetic flux distribution in different radial zones, reducing leakage flux and harmonic components while maintaining high torque output.
Solution Approach 2:
The patent changes the geometric parameters of the permanent magnets, specifically the width parameter. By setting the outer-layer magnet width to be smaller than the inner-layer magnet width, the patent optimizes the magnetic flux density distribution and reduces the harmonic components that cause torque pulsation, while still achieving high reluctance torque and magnet torque.
3Quantity of substance
If two-layer magnet structure is used, then magnetic flux density is increased, but harmonic components increase causing increased torque pulsation
Solution Approach 1:
The patent applies local quality by differentiating the magnet widths in the two layers. The inner-layer magnets have a first width while the outer-layer magnets have a second width that is smaller than the first width. This local differentiation optimizes the magnetic flux distribution in different radial zones, reducing leakage flux and harmonic components while maintaining high torque output.
Solution Approach 2:
The patent changes the geometric parameters of the permanent magnets, specifically the width parameter. By setting the outer-layer magnet width to be smaller than the inner-layer magnet width, the patent optimizes the magnetic flux density distribution and reduces the harmonic components that cause torque pulsation, while still achieving high reluctance torque and magnet torque.
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 design effectively reduces vibration and noise by minimizing harmonic components of the rotor magnetomotive force, thereby enhancing the torque consistency and reducing magnetic saturation, which in turn decreases the gap magnetic flux density and harmonic content.
Implementation Method 1
a magnetic flux generated from an armature winding of a stator, magnet torque due to attraction and repulsion of a magnetic flux generated from permanent magnets of a rotor
Implementation Method 2
torque is improved by a magnetic flux generated from an armature winding of a stator, magnet torque due to attraction and repulsion of a magnetic flux generated from permanent magnets of a rotor
Implementation Method 3
reluctance torque due to magnetic saliency of the rotor
Implementation Method 4
a magnet width excluding a magnet width for magnetically saturating a first-layer center bridge and a magnet width for magnetically saturating a first-layer radially-outer bridge
Data Source
AI summary
In a rotor in which magnet slots arranged in a V shape so as to open toward the outer circumferential side and having permanent magnets inserted therein are formed in a two-layer structure in a radial direction, the magnet slots in each layer are composed of a pair of slots formed between a center bridge located at the center and respective ones of two radially-outer bridges located between the outer surface of the rotor and the respective slots. Of magnetic fluxes generated from the permanent magnets, magnetic fluxes excluding magnetic fluxes for magnetically saturating the bridges are defined as effective magnetic fluxes. The rotor is configured such that the effective magnetic flux generated from the permanent magnet on the radially outer side is not greater than half the effective magnetic flux generated from the permanent magnet on the radially inner side.