Linear Power Generator Cogging Reduction via Yoke Segmentation
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Solution Overview
Problem
In linear power generators, cogging forces hinder smooth reciprocating motion and efficient power generation due to the lack of constraints on these forces, unlike in rotary power generators.
Innovation Solution
The design incorporates center and outer yokes with strategically positioned projecting portions to maintain constant attractive forces and prevent cogging by ensuring consistent magnetic flux densities across the yokes' interaction, allowing for efficient power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cogging is not constrained in the linear power generator, then the structure remains simple, but the cogging force prevents smooth reciprocating motion and reduces power generation efficiency
Solution Approach 1:
The yoke is divided into multiple segments along the circumferential direction, with each segment containing permanent magnets. This segmentation allows independent positioning of magnetic poles, enabling the creation of multiple magnetic poles (e.g., 4 poles) that interact to produce balanced magnetic forces, thereby reducing cogging while maintaining structural simplicity
Solution Approach 2:
The patent employs asymmetric positioning of permanent magnets within yoke segments, where magnets are arranged at specific angular intervals (e.g., 45 degrees apart) to create a balanced magnetic field distribution. This asymmetric arrangement ensures that attractive and repulsive forces are evenly distributed, minimizing net cogging force on the reciprocating component
2Ease of operation
If cogging is constrained through strategic positioning of projecting portions, then smooth reciprocating motion is achieved, but the manufacturing complexity increases
Solution Approach 1:
The yoke segments and permanent magnets are pre-positioned and fixed in their optimal configurations before assembly. This preliminary action ensures that the magnetic poles are correctly aligned to minimize cogging, and the structure is ready for smooth operation without requiring complex adjustment mechanisms during assembly or operation
Solution Approach 2:
The patent employs a nested structure where permanent magnets are embedded within yoke segments, which are then assembled into the complete yoke. This nesting approach simplifies manufacturing by allowing separate fabrication of components that are later integrated, reducing overall manufacturing complexity while achieving the desired magnetic field configuration
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 ensures continuous power generation by maintaining constant attractive forces and minimizing cogging, thus optimizing the reciprocating motion for efficient energy conversion.
Implementation Method 1
ensure consistent magnetic flux densities across the yokes' interaction
Implementation Method 2
maintain constant attractive forces
Implementation Method 3
power generated in the winding portion by reciprocating motion of the center yoke
Data Source
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AI summary
One aspect of the present invention provides a linear power generator in which cogging is sufficiently constrained. The linear power generator (1) includes a columnar or cylindrical center yoke (2) made of a soft magnetic material and an outer yoke (3) made of a soft magnetic material. In the center yoke (2), plural rod-shaped permanent magnets (10) magnetized in a circumferential direction are arranged in the circumferential direction in an outer circumference of the center yoke (2) such that opposed magnetic poles of the permanent magnets (10) adjacent to each other become identical, the permanent magnets (10) are extended in an axial direction, and the center yoke (2) includes plural center-side projecting portions (11a) linearly arranged in the circumferential direction. The cylindrical or columnar outer yoke (3) includes plural winding portions (25), plural groove portions (22), and an outer-side projecting portion (23a). The winding portions (25) are arranged in the circumferential direction about a center axis. The groove portions (22) are arranged at positions opposed to the permanent magnets (10). The outer-side projecting portion (23a) is arranged while opposed to the center-side projecting portion (11), the outer-side projecting portion (23a) is deviated from the center-side projecting portion (11a) by a half pitch, and the groove portion (22) is pinched by the outer-side projecting portion (23a) in the circumferential direction.