Segmented Baseplate for PM Machine Eddy Current Reduction
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Solution Overview
Problem
Permanent magnet machines in wind turbines experience high eddy current losses due to magnetic fields, leading to increased temperatures, reduced performance, and efficiency, with existing solutions like laminated materials being costly and compromising mechanical strength, or requiring expensive alternative fixing methods.
Innovation Solution
A permanent magnet module with a baseplate featuring a laminated or soft magnetic composite second portion to reduce eddy current losses, where the second portion is attached to the permanent magnet, and a stainless steel first portion for mechanical strength, allowing for conventional welding of the cover without affecting assembly or structural performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If laminated materials are used in the baseplate to reduce eddy current losses, then eddy current losses are reduced, but mechanical strength is largely reduced and cost increases
Solution Approach 1:
The baseplate is divided into two distinct portions: a first portion made of solid steel for mechanical strength and attachment, and a second portion made of laminated material for reducing eddy current losses. This segmentation allows each portion to fulfill its specific function optimally without compromising the other.
Solution Approach 2:
Different portions of the baseplate are assigned different material properties: the first portion (lower part) uses solid steel for strength and welding, while the second portion (upper part) uses laminated material for eddy current reduction. This local differentiation of material quality resolves the contradiction between strength and loss reduction.
2Loss of energy
If soft magnetic composite (SMC) materials are used in the baseplate to reduce eddy current losses, then eddy current losses are reduced, but welding capability is prevented
Solution Approach 1:
The baseplate is segmented into a first portion made of weldable solid steel and a second portion made of SMC material for eddy current reduction. The solid steel first portion maintains welding capability while the SMC second portion reduces losses, resolving the contradiction between manufacturing ease and energy loss reduction.
Solution Approach 2:
The first portion is assigned weldable solid steel material properties while the second portion uses SMC material for loss reduction. This local quality differentiation allows welding operations to be performed on the first portion without affecting the electrical properties of the second portion.
3Strength
If a solid baseplate is used to maintain mechanical strength, then mechanical strength is maintained, but eddy current losses increase
Solution Approach 1:
The baseplate is divided into a first portion made of solid steel for mechanical strength and a second portion made of laminated or SMC material for reducing eddy current losses. This segmentation allows the solid portion to maintain strength while the laminated portion reduces losses.
Solution Approach 2:
The first portion uses solid steel material for strength while the second portion uses laminated material with different electrical properties for loss reduction. This local quality differentiation resolves the contradiction between maintaining strength and reducing eddy current 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
Significantly reduces eddy current losses by up to 50% while maintaining mechanical strength and allowing for cost-effective construction, enhancing the efficiency and Annual Energy Production (AEP) of the generator.
Implementation Method 1
eddy currents are induced due to asynchronous rotating fields in the airgap
Implementation Method 2
The second portion has a structure for reducing eddy current losses or comprises a material for reducing eddy current losses
Implementation Method 3
eddy currents are induced due to asynchronous rotating fields in the airgap
Implementation Method 4
The second portion has a structure for reducing eddy current losses or comprises a material for reducing eddy current losses
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention describes a permanent magnet module (101, 102) for a permanent magnet machine (10). The permanent magnet module (101, 102) comprises at least a permanent magnet (200) and a baseplate (301, 302), the baseplate (301, 302) including at least a first portion (400) and a second portion (501, 502), the first portion (400) providing an interface for attaching the permanent magnet module (101, 102) to a permanent magnet machine (10) and the second portion (501, 502)being attached to the at least one permanent magnet (200), wherein the second portion (501, 502)has a structure or comprises a material for reducing eddy current losses.