Skewed Permanent Magnet Modules for Electric Machine Rotors
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Solution Overview
Problem
The existing assembly methods for permanent magnet electric machines result in permanent magnet modules being arranged in axially directed straight rows, which can lead to cogging torque and voltage harmonics, necessitating a deviation from this construction to achieve improved performance.
Innovation Solution
The design incorporates permanent magnet modules with base-plates having bottom sections arranged in axially directed straight rows and upper sections positioned differently, allowing the permanent magnet elements to be arranged in rows skewed or deviating from the axial direction, facilitating assembly and attachment without complicating the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If permanent magnet modules are arranged in axially directed straight rows to simplify assembly, then ease of manufacture is improved, but cogging torque and voltage harmonics increase
Solution Approach 1:
The permanent magnet modules are segmented into different subsets with different axial positions of upper sections relative to bottom sections. This segmentation allows the bottom sections to be arranged in straight rows for easy assembly while the upper sections with permanent magnet elements are positioned at different axial locations to create skewed arrangements that reduce cogging torque and voltage harmonics.
Solution Approach 2:
The invention introduces axial offset as an additional dimension for positioning permanent magnet elements. By varying the axial position of upper sections relative to bottom sections across different subsets, the permanent magnet elements achieve skewed three-dimensional arrangements that reduce harmful electromagnetic effects while maintaining straightforward assembly of the base structure.
2Object-generated harmful factors
If permanent magnet elements are arranged in skewed rows to reduce cogging torque, then performance is improved, but assembly complexity increases
Solution Approach 1:
The permanent magnet modules are divided into subsets where each subset has a specific axial offset configuration. This segmentation allows complex skewed arrangements to be achieved through simple modular variations rather than complex individual positioning, reducing overall assembly complexity.
Solution Approach 2:
The base-plates with bottom sections are pre-configured in straight rows with standardized positions. This preliminary arrangement simplifies the assembly process by establishing a regular base structure, while the permanent magnet elements achieve skewed positions through the pre-designed axial offsets of upper sections in different subsets.
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 configuration enables the construction of rotors with skewed or non-straight permanent magnet element arrangements, reducing cogging torque and voltage harmonics while maintaining straightforward assembly and fastening, enhancing the performance of permanent magnet electric machines.
Implementation Method 1
permanent magnet electric machine that can be, for example but not necessarily, a generator of a wind power plant
Implementation Method 2
permanent magnets generate magnetic field without losses
Data Source
AI summary
Each permanent magnet module for a permanent magnet rotor includes a base-plate and a permanent magnet element attached to the base-plate. The base-plate includes a bottom section and an upper section between the bottom section and the permanent magnet element. The permanent magnet modules constitute subsets so that permanent magnet modules of different subsets differ from each other by positions of the upper sections of the base-plates with respect to the bottom sections of the base-plates so that the permanent magnet elements of the permanent magnet modules of the different subsets are axially successive and circumferentially shifted when the bottom sections of these permanent magnet modules are axially successive and circumferentially aligned. Thus, the permanent magnet elements of the permanent magnet modules can be arranged into, for example, skewed rows on a surface of the rotor.