Rotor Flux Shields for Higher Torque Density in Compact Motors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric motors face limitations in achieving high torque and power densities in compact designs, necessitating innovative approaches to enhance motor performance without increasing size or relying solely on stronger magnetic fields.
Innovation Solution
The integration of flux barriers made from electrically conductive materials between rotor poles, which alter the path of magnetic flux to increase the magnetically induced motive force, allowing for higher torque and power densities by redirecting magnetic flux more tangentially, thereby improving motor efficiency and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the size of the motor is increased to achieve higher torque and power densities, then the motor performance is improved, but the compactness and applicability are reduced
Solution Approach 1:
The patent changes the magnetic flux distribution parameters by introducing flux barriers with specific electrical conductivity properties. The flux barriers have higher electrical conductivity than the surrounding ferromagnetic material, which alters the magnetic flux path to increase the tangential component. This parameter change enables higher torque density without increasing motor volume.
Solution Approach 2:
The patent employs composite magnetic circuit structures combining ferromagnetic material with flux barriers of different electrical conductivity. This composite approach creates optimized magnetic flux paths that enhance torque production while maintaining compact dimensions, resolving the contradiction between power density and size.
2Force
If stronger magnetic fields are created to increase electromagnetic force, then motor performance is improved, but the complexity and cost of magnetic materials increase
Solution Approach 1:
The patent replaces the conventional approach of using stronger magnets or higher current with a geometric and material property-based solution. By strategically placing flux barriers with specific conductivity properties, the system redirects existing magnetic flux to produce higher electromagnetic force without requiring stronger magnetic fields, thus reducing complexity.
Solution Approach 2:
The flux barriers act as intermediary elements that mediate the magnetic flux distribution. These barriers with higher electrical conductivity than ferromagnetic material serve as conductors that redirect flux paths, enabling enhanced force production without directly increasing magnetic field strength or complexity.
3Volume of moving object
If conventional motor designs are used to achieve compact size, then motor compactness is maintained, but torque and power densities are limited
Solution Approach 1:
The patent applies local quality changes by introducing flux barriers with specific electrical conductivity properties at strategic locations within the motor. The flux barriers have higher electrical conductivity than the surrounding ferromagnetic material, creating localized regions that redirect magnetic flux to enhance torque production while maintaining overall compact dimensions.
4Power
If magnetic flux is redirected more tangentially to increase motive force, then torque density is improved, but magnetic fringing effects may increase
Solution Approach 1:
The patent changes the magnetic flux distribution parameters by using flux barriers with higher electrical conductivity than ferromagnetic material. This parameter change redirects flux more tangentially to increase motive force while the controlled geometry of flux barriers helps manage fringing effects.
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 design significantly enhances torque and power densities, allowing for more efficient energy transfer and reduced magnetic fringing, leading to improved motor performance and efficiency, particularly in compact motor applications.
Implementation Method 1
flux barriers made from electrically conductive materials between rotor poles, which alter the path of magnetic flux to increase the magnetically induced motive force
Implementation Method 2
alter the path of magnetic flux to increase the magnetically induced motive force
Implementation Method 3
Generally, eddy currents will be induced in the flux barrier that cause destructive interference of an impending magnetic field, such that the flux barrier effectively acts to inhibit a change in magnetic flux during motor operation, which in some cases will result in a repulsive force
Implementation Method 4
eddy currents will be induced in the flux barrier that cause destructive interference of an impending magnetic field... which in some cases will result in a repulsive force that will act to increase an induced motive force on the passive poles
Data Source
AI summary
An electric motor has a stator defining multiple stator poles with associated electrical windings, and a rotor having multiple rotor poles. The rotor has flux barriers between adjacent rotor poles, the flux barriers each having a material with an electrical conductivity higher than the rotor pole material. The flux barriers are electrically isolated from one another external to the ferromagnetic material. Eddy currents are induced in the flux barrier to cause destructive interference of an impending magnetic field, such that the flux barrier effectively acts to inhibit magnetic flux during motor operation, which in some cases will result in a repulsive force that will act to increase an induced motive force on the rotor poles.