Integrated Electric Machine Coils for High-Frequency Loss Reduction
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Solution Overview
Problem
Large electric machines face power losses due to parasitic effects like the Skin Effect and Proximity Effect, especially at high frequencies, and traditional designs are inefficient in minimizing these losses, leading to suboptimal power density and efficiency.
Innovation Solution
The design optimizes the geometry of stator coils and cores using the Dowell approach and Nonlinear Conjugate Gradient method to minimize AC resistance, with varying conductor thickness and shape to reduce parasitic effects, and integrates power electronics and coolant systems to enhance cooling and reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the supply frequency is increased to increase power density, then power density is improved, but parasitic effects (Skin Effect and Proximity Effect) increase causing power losses
Solution Approach 1:
The patent applies parameter changes by optimizing the slot fill factor through specific geometric configurations of the stator core slots and conductor arrangement. The slot fill factor is increased to 0.55 or higher through careful design of slot dimensions, conductor shape, and packing arrangement, which reduces the AC resistance and mitigates parasitic effects at high frequencies, thereby enabling high power density operation with reduced power losses
Solution Approach 2:
The patent employs composite material strategies by using high-permeability magnetic materials for the stator core with optimized magnetic properties. The core material is selected and designed to have appropriate saturation flux density and permeability characteristics that minimize eddy current losses and improve the overall magnetic circuit efficiency, reducing parasitic effects while maintaining high power density
2Power
If the size of electric machine is increased, then power output is improved, but parasitic effects become more significant causing efficiency degradation
Solution Approach 1:
The patent applies parameter changes by scaling the slot fill factor and geometric parameters proportionally with machine size. The slot dimensions, conductor cross-sections, and winding configurations are optimized together to maintain high slot fill factors across different size scales. This ensures that larger machines achieve the same reduced AC resistance and parasitic effect mitigation as smaller machines, enabling efficient high-power operation
Solution Approach 2:
The patent applies local quality by optimizing the magnetic material properties and geometric parameters in different regions of the stator core. The core is designed with varying local characteristics including different yoke thicknesses, tooth dimensions, and slot geometries in different zones to minimize flux density variations and reduce eddy current losses throughout the entire magnetic circuit, thereby mitigating parasitic effects in large machines
3Quantity of substance
If traditional slot designs are used to increase slot fill factor, then conductor material amount is improved, but manufacturing complexity and inefficiency increase
Solution Approach 1:
The patent applies segmentation by dividing the stator core into modular units with standardized slot geometries and conductor configurations. The core is designed with repeating patterns of slots, teeth, and yoke sections that can be manufactured independently and assembled systematically. This modular approach maintains high slot fill factors while significantly improving manufacturing efficiency through standardization and reduced complexity
Solution Approach 2:
The patent applies universality by designing a standardized slot and conductor configuration that serves multiple functions: achieving high slot fill factor, facilitating easy manufacturing, enabling effective cooling, and maintaining electrical performance. The universal geometric parameters and conductor shapes are optimized to simultaneously satisfy multiple design requirements, reducing the need for complex custom designs and improving overall manufacturing efficiency
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 reduces power losses by an order of magnitude and improves power density, enabling efficient operation at high frequencies in large electric machines.
Implementation Method 1
An electric machine typically includes a rotor and a stator. In some designs, the stator includes a core about which a wire is wound to form a coil.
Implementation Method 2
increasing the supply frequency may result in two types of parasitic effects known as the 'Skin Effect' and the 'Proximity Effect'
Implementation Method 3
increasing the supply frequency may result in two types of parasitic effects known as the 'Skin Effect' and the 'Proximity Effect'
Data Source
AI summary
Improved electric machines with tuned coils, integrated power electronics, and stator and rotor cooling assemblies.