Concentric Dual-Axis Alternator Layout for Compact Field Control
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Solution Overview
Problem
Existing alternator designs, such as permanent magnet generators, face challenges with space efficiency and flexibility due to the permanent nature of magnets, which limits their use in applications where space is constrained and requires significant space, and they are less flexible in electrical operation.
Innovation Solution
A dual axis generator design where the exciter generator and main generator are arranged concentrically around a common shaft, reducing axial space requirements while maintaining control flexibility, utilizing a controlled field system that can be integrated with a flywheel to optimize power density and reduce torque variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separately excitable generator with an exciter generator is used, then control flexibility is improved, but the axial space requirement increases by 5-30%
Solution Approach 1:
The exciter generator is nested within the main generator structure, with the exciter rotor positioned inside the main stator and the main rotor positioned outside the exciter stator. Both generators share a common shaft and rotate together, allowing the exciter to be housed within the spatial envelope of the main generator, thereby eliminating the need for additional axial space while maintaining separate excitation control capability.
2Length of stationary object
If permanent magnet generators are used, then space efficiency is improved, but control flexibility deteriorates due to the permanent nature of magnets
Solution Approach 1:
The invention replaces static permanent magnets with dynamic electromagnetic fields. The exciter generator produces a controllable rotating magnetic field that interacts with the main generator rotor, enabling the magnetic field strength and polarity to be dynamically adjusted through electrical control of the exciter, thereby achieving control flexibility without sacrificing space efficiency.
Solution Approach 2:
The exciter generator acts as an intermediary between the electrical control system and the main generator. By controlling the exciter's field current and output, the invention indirectly controls the main generator's magnetic field and output characteristics, providing a mediator mechanism that enables flexible control while maintaining a compact permanent magnet-like structure.
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
The dual axis generator achieves space efficiency similar to permanent magnet generators while offering the control flexibility of controlled field generators, optimizing power density and reducing torque variations through a concentric design that integrates the exciter and main components within a flywheel, enhancing operational flexibility and efficiency.
Implementation Method 1
As the exciter armature is rotated in a magnetic flux, a time varying voltage is induced in the windings of the exciter armature.
Implementation Method 2
As the field portion of the alternator is rotated relative to the stator, a magnetic flux is passed through and across the alternator stator windings producing time varying voltage.
Data Source
AI summary
An alternator includes an exciter field device generating an exciter magnetic field in a first air gap, an exciter armature device configured to rotate with respect to the exciter magnetic field and impart a first voltage in a first set of coils at the first air gap, a main stator device including a second set of coils, and a rotor field device configured to be energized by the first current in the first set of coils and generate a main magnetic field that imparts a second voltage on the main stator device at a second air gap. The main stator device and the exciter field device lie in on a common plane normal to an axis of rotation, and the exciter armature device is inwardly spaced from the exciter field device, main stator device, and the rotor field device.