Bundled Armature Windings to Limit Circulating Current in Motors
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Solution Overview
Problem
Rotating electrical machines face issues with high electrical current circulation due to varying magnetic flux interlinkage, leading to increased voltage differences across conductor portions, which can result in excessive current flow and potential magnetic saturation in the stator teeth, reducing torque output.
Innovation Solution
The design incorporates a magnetic field-producing unit with alternately arranged magnetic poles, armature windings with conductor portions made of bundled wires, and a rotor structure that optimizes the arrangement of magnet-facing portions to reduce voltage differences across wires, along with the use of conductor-to-conductor members and a slot-less stator structure to minimize magnetic saturation and enhance torque production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wires are connected in parallel to form closed loop circuits, then eddy-current loss is reduced, but voltage difference between wires increases causing excessive current circulation
Solution Approach 1:
The conductor portion is divided into multiple independent insulated wires instead of a solid conductor. Each wire is electrically isolated from others, preventing the formation of closed loop circuits. This segmentation eliminates the circulating current path while maintaining the reduced eddy-current loss benefit.
Solution Approach 2:
An insulating layer is introduced between adjacent wires to prevent electrical contact. This intermediary material blocks the formation of closed loops between wires, eliminating the circulating current issue while allowing each wire to independently experience reduced eddy-current loss.
2Loss of energy
If conductor portions are made of bundled wires, then eddy-current loss is reduced, but manufacturing complexity increases
Solution Approach 1:
The conductor is segmented into multiple thin insulated wires that can be individually manufactured and then easily assembled into bundles. This segmentation approach reduces eddy-current loss while the modular nature of insulated wires simplifies the bundling process compared to machining grooves into solid conductors.
Solution Approach 2:
The conductor uses a composite structure of multiple insulated wires bundled together. Each wire is a composite of conductive material and insulating coating, creating a flexible, easy-to-manufacture bundle that achieves reduced eddy-current loss without complex manufacturing processes.
3Use of energy by moving object
If stator teeth are present, then magnetic flux path is provided, but magnetic saturation occurs reducing torque output
Solution Approach 1:
The stator teeth are completely removed from the stator core structure. This extraction eliminates the magnetic saturation problem that limited torque output, while the magnetic flux path is maintained through the continuous stator core and rotor magnet arrangement.
Solution Approach 2:
Instead of providing magnetic flux path through discrete teeth, the design inverts the approach by using a continuous stator core structure. The magnetic flux flows through the continuous core and rotor magnets, eliminating saturation while maintaining efficient flux path.
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 effectively reduces electrical current circulation, enhances torque output by minimizing magnetic saturation, and optimizes magnetic flux distribution, leading to improved efficiency and performance in rotating electrical machines.
Implementation Method 1
A rotating electrical machine is known which is, as described in patent literature 1, equipped with a field-producing unit and an armature. The field-producing unit has a plurality of magnetic poles whose polarities are arranged alternately in a circumferential direction thereof.
Implementation Method 2
The armature is equipped with multiple phase armature windings. The armature winding of each phase includes a conductor portion which is equipped with magnetic facing portions which face the magnet unit and are arranged at a given interval away from each other in the circumferential direction.
Implementation Method 3
There are rotating electrical machines in which the conductor portion are each made of a collection or bundle of a plurality of wires, and a value of resistance between the bundled wires is higher than that of each of the wires itself. Such a structure serves to reduce eddy-current loss arising from interlinkage of a magnet-produce magnetic field, as created by a magnet unit, with the conductor portions.
Data Source
AI summary
A rotating electrical machine has a magnetic field-producing unit, an armature with armature windings for multiple phases, and a rotor implemented by one of the magnetic field-producing unit and armature. The armature winding of each phase has a conductor portion. The conductor portion is made of a bundle of wires and has a resistance value between the bundled wires larger than that within each of the wires. Each conductor portion includes magnet facing portions arranged at a given interval away from each other and face the magnet unit. The magnet facing portions of the same phase are connected in series. The wires of the conductor portion of the same phase are connected in parallel. The order of locations of the wires of each of the magnet facing portions for the same phase is different between given portions of the magnet facing portion in an axial direction of the rotor.