Stator Winding Geometry Tuning for High-Frequency AC Loss Reduction
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Solution Overview
Problem
High frequency electric machines face challenges due to parasitic effects like the Skin Effect and Proximity Effect, which hinder their ability to utilize high frequency supply sources effectively, particularly in large-sized machines.
Innovation Solution
The optimization of stator winding geometry using a computing device, considering parasitic effects such as skin and proximity effects, through methods like the nonlinear conjugate gradient approach, to minimize AC resistive losses, with varying conductor sizes and geometries inside and outside slots, and elongated slots to reduce energy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the supply frequency of an electric machine is increased to decrease its weight and size, then the machine weight and size are reduced, but parasitic effects (skin effect and proximity effect) increase, leading to higher AC resistive losses
Solution Approach 1:
The patent applies local quality by varying the conductor geometry specifically in the slot region where parasitic effects are most severe. The first portion of the conductor inside the slot has optimized dimensions (width, height, position) different from the second portion outside the slot, creating local geometric variations that reduce skin and proximity effects precisely where they occur most intensely.
Solution Approach 2:
The patent implements parameter changes by optimizing multiple geometric parameters of the conductor including width, height, position within the slot, and the number of layers. These parameter variations are specifically tailored to minimize AC resistance at high frequencies while maintaining the desired power density and machine size.
2Power
If large conductor sizes are used in electric machines, then the power handling capability is improved, but the skin effect and proximity effect intensify, increasing AC resistive losses
Solution Approach 1:
The patent applies local quality by creating non-uniform conductor geometry where the first portion inside the slot has different dimensions than the second portion outside. This local variation allows the conductor to handle large power while minimizing the impact of parasitic effects in the critical slot region where magnetic fields are strongest.
Solution Approach 2:
The patent utilizes dimensional optimization by adjusting the conductor's width, height, and position within the slot. This multi-dimensional geometric optimization allows large conductors to be configured in a way that reduces the severity of skin and proximity effects while maintaining power handling capability.
3Weight of moving object
If high frequency supply is used in large size electric machines, then the weight and size reduction benefit is achieved, but the parasitic effects prevent full advantage utilization
Solution Approach 1:
The patent applies local quality by optimizing the conductor geometry specifically in the slot region to address parasitic effects that become severe at high frequencies. This localized geometric optimization enables large machines to operate effectively at high frequencies by minimizing AC losses in the most critical area.
Solution Approach 2:
The patent implements parameter changes by adjusting conductor dimensions and positioning to specifically address high frequency operation challenges. These parameter optimizations enable large electric machines to reliably operate at high frequencies, achieving the desired weight and size reductions while maintaining effectiveness.
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 approach enables high power, high frequency electric machines to achieve reduced weight and size while minimizing AC resistive losses, making them suitable for applications like electric flight and hybrid jet engines, and can be applied to various electric machine categories.
Implementation Method 1
increasing the frequency produces two parasitic effects known as the 'Skin Effect' and the 'Proximity Effect'
Implementation Method 2
increasing the frequency produces two parasitic effects known as the 'Skin Effect' and the 'Proximity Effect'
Data Source
AI summary
An example method of producing an electric machine is described herein. The method can include providing the electric machine. The electric machine can include a rotor and a stator, where the stator includes a magnetic core and a stator winding. Additionally, the magnetic core can include a plurality of teeth defining a plurality of slots between adjacent teeth. The stator winding can also include a first portion arranged inside a slot and a second portion arranged outside the slot. The method can further include optimizing, using a computing device, a geometry of the first portion of the stator winding, where the first portion of the stator winding in the provided electric machine has the optimized geometry.