Three-Material Stator Structure for Ring Coil Interference Reduction
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Solution Overview
Problem
Conventional electric machine configurations with ring coils often interfere geometrically and electromagnetically with the stator structure, limiting their application and requiring complex reconfigurations, and existing materials do not adequately address parasitic losses and manufacturing challenges.
Innovation Solution
The electric machine incorporates a stator made of three distinct materials: a high-magnetic back iron, non-magnetic connectors with high electric resistivity, and a rigid, machinable central hub, with ring coils wound around the bearing between teeth, and connectors welded to tabs for assembly, allowing for minimal interference and efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If ring coils are used in the stator, then the leakage inductance is reduced and high frequency behavior is improved, but geometric and electromagnetic interference with the stator structure occurs
Solution Approach 1:
The stator is segmented into multiple independent teeth, each capable of carrying ring coils. This segmentation allows the magnetic flux to be confined within each tooth-coil assembly, reducing electromagnetic interference with adjacent stator components while maintaining the low leakage inductance benefit of ring coils.
Solution Approach 2:
Different regions of the stator are designed with different properties - the teeth are made of high-permeability magnetic material to concentrate flux, while the yoke provides a low-reluctance path. This local differentiation allows ring coils to operate effectively without causing broad electromagnetic interference across the entire stator structure.
2Ease of manufacture
If conventional single-material stator construction is used, then manufacturing is simpler, but parasitic losses increase and performance is limited
Solution Approach 1:
The stator employs composite construction using multiple materials with different magnetic properties - high-permeability magnetic steel for the teeth and yoke, and non-magnetic materials for specific components. This composite approach reduces parasitic losses by directing flux through optimal paths while eliminating eddy current losses in non-critical areas, all while maintaining manufacturing feasibility through standardized material components.
3Stability of the object's composition
If the central hub is made of the same magnetic material as the back iron, then magnetic properties are consistent, but rigidity and machinability are compromised
Solution Approach 1:
The central hub is extracted from the magnetic circuit path, allowing it to be made from non-magnetic or low-magnetic materials optimized for mechanical strength and machinability. The magnetic flux is routed through the teeth and yoke, bypassing the hub, which eliminates the need for the hub material to have specific magnetic properties while maintaining overall magnetic circuit efficiency.
4Ease of manufacture
If connectors are made of magnetic material, then welding to the back iron is easier, but electromagnetic interference and parasitic losses increase
Solution Approach 1:
The connectors use non-magnetic materials that act as intermediaries between the magnetic back iron and the central hub. These connectors are positioned outside the main magnetic flux path, eliminating parasitic losses and electromagnetic interference while maintaining structural integrity. The welding process is facilitated by preparing the connection surfaces on the magnetic back iron, allowing easy attachment of non-magnetic connector materials.
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 minimizes electromagnetic interference, reduces parasitic losses, and enables mass production of high-torque electric machines with improved rigidity and machinability, suitable for applications like electric vehicles, while allowing for efficient welding and assembly processes.
Implementation Method 1
The back iron is made of a first material and at least one connector is made of a second material that is different from the first material. the first material may have high magnetic properties
Implementation Method 2
the second material may have non-magnetic properties with high electric resistivity
Implementation Method 3
The AC electric motor is coupled to the DC power source via a power inverter that performs switching functions to convert the DC power to AC power
Data Source
AI summary
The electric machine includes a rotor and an internal stator operatively coupled to the rotor. The internal stator further includes a back iron having a bearing and a plurality of teeth, a plurality of ring coils wound around the back iron, a central hub, and a plurality of connectors that connects the central hub to the back iron. The back iron is made of a first material and at least one connector is made of a second material that is different from the first material.