Cylindrical Direct Drive Generator with Interleaved Annuli
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Solution Overview
Problem
Existing wind and tidal energy conversion systems using direct drive generators face challenges with large component sizes disrupting airflow, high maintenance costs due to rare earth magnets, and inefficiencies in electromagnetic force generation.
Innovation Solution
The design employs coaxial cylinders with self-contained interleaving stator and armature annuli, using low-grade ferrite magnets and circular coils, optimizing magnetic flux and reducing component size and material costs, while minimizing flux leakage through strategic magnet placement and coil arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large diameter planar stator and armature are used to compensate for slow rotary speed, then electromagnetic force generation is improved, but wind flow disruption and device complexity increase
Solution Approach 1:
The patent transitions from a planar two-dimensional generator design to a three-dimensional cylindrical design with coaxial stator and armature. This dimensional change allows the generator to produce electromagnetic force along the axial direction rather than requiring a large planar surface area, thereby maintaining power generation capability while reducing wind flow disruption.
Solution Approach 2:
The cylindrical generator is divided into multiple segments including interleaved stator and armature annuli, allowing the magnetic circuit to be distributed along the axial length rather than requiring a large radial diameter. This segmentation enables compact design while maintaining sufficient electromagnetic force generation.
2Power
If rare earth permanent magnets are used to provide high field strengths, then power generation efficiency is improved, but material cost and supply constraints increase
Solution Approach 1:
The patent changes the magnetic material parameter from rare earth permanent magnets to ferrite magnets. This substitution uses abundant, low-cost ferrite material while maintaining sufficient magnetic field strength through optimized magnetic circuit design including interleaved annular structures and strategic placement of magnets and coils.
Solution Approach 2:
The patent employs composite construction with ferrite magnets combined with ferromagnetic materials in the annular structures. This composite approach enhances the overall magnetic circuit efficiency, allowing the use of lower-cost ferrite magnets while achieving required field strengths through the synergistic combination of materials.
3Power
If flat rectangular magnets and coils are used to maximize flux utilization, then electromagnetic force generation is improved, but manufacturing complexity and material cost increase
Solution Approach 1:
The patent replaces flat rectangular magnets and coils with curved annular configurations that follow the cylindrical geometry. The magnets are arranged in annular patterns around the cylindrical core, and coils are wound concentrically, simplifying manufacturing while maintaining effective flux utilization through the curved magnetic paths.
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 enhances electromagnetic force generation efficiency, reduces material costs significantly, and minimizes maintenance challenges by using abundant ferrite magnets, while maintaining effective energy conversion with a more compact and efficient generator design.
Implementation Method 1
the coils are mounted in effect upon a separate annulus, sandwiched between the magnets, and which is mechanically linked to the rotor such that rotation of the rotor causes the coil carrying annulus to rotate and thus cut the lines of flux provided by the magnets. An electro-magnetic force (emf) is thereby generated.
Data Source
Figure 1~2
Figure 3a~3c
Figure 4~5b
AI summary
A direct drive rotary generator formed of an elongate cylindrical series of stator annuli and a coaxial elongate cylindrical series of armature annuli and mounted for relative rotational movement around their common axis, the series of stator annuli interleaving the series of armature annuli, and either of the armature/stator annuli having a contiguous or substantially contiguous sequence of coils around its circumference, and the other of the armature/stator annuli having a corresponding sequence of permanent magnets of alternating polarity spaced around its circumference and at the same pitch as that of the coils, the arrangement being such that lines of magnetic flux passing across the air gap between one magnet carrying annulus to the next cut the turns of the coils of the corresponding interleaved coil carrying annulus, and thus induce in the coils electromagnetic forces as the armature is caused to rotate relative to the stator.