Eddy Current Repulsion Motor Reduces Rotor Weight
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Solution Overview
Problem
Current electric motors used in aircraft and other applications face challenges with weight, cost, responsiveness, and speed due to the use of ferromagnetic materials and complex assembly processes, leading to increased inertia and limited performance.
Innovation Solution
The development of an electric motor with a rotor made of electrically conductive materials, utilizing repulsive forces generated by eddy currents to reduce weight and complexity, and a current control system that controls alternating current flow to optimize torque and speed without the need for permanent magnets or heavy components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If ferromagnetic materials are used in the rotor, then the motor can generate sufficient torque, but the weight of the rotor increases
Solution Approach 1:
The patent changes the fundamental operating principle from magnetic attraction (ferromagnetic) to electromagnetic induction (eddy currents). By using an electrically conductive rotor without ferromagnetic materials and driving it with high-frequency AC through stator coils, the motor generates torque through repulsive eddy currents rather than magnetic attraction, thereby eliminating the need for heavy ferromagnetic rotor materials
Solution Approach 2:
The patent replaces the traditional mechanical/magnetic attraction-based rotor-stator interaction with an electromagnetic repulsion mechanism. The stator coils generate a time-varying magnetic field that induces eddy currents in the conductive rotor, creating a repulsive force that drives rotation, substituting the need for ferromagnetic materials and their associated weight
2Loss of energy
If permanent magnets are used in the rotor, then the motor achieves high efficiency, but the cost and manufacturing complexity increase
Solution Approach 1:
The patent extracts and eliminates permanent magnets from the motor design entirely. By using an electrically conductive rotor material and generating the necessary magnetic interactions through induced eddy currents from the stator coils, the motor achieves its function without requiring any permanent magnets, thereby reducing both cost and manufacturing complexity
Solution Approach 2:
The rotor material serves dual purposes: it provides structural integrity and simultaneously generates the necessary electromagnetic interaction through induced eddy currents. The electrically conductive rotor material essentially serves itself by converting the stator's magnetic field into the repulsive force needed for rotation, eliminating the need for separate permanent magnet components
3Strength
If the rotor uses heavy materials, then the motor structure is more robust, but the responsiveness and speed decrease
Solution Approach 1:
The patent changes the rotor material properties from heavy ferromagnetic materials to lightweight electrically conductive materials. This parameter change enables both high structural robustness and high speed performance by reducing rotational inertia while maintaining sufficient mechanical strength through the conductive material selection
4Manufacturing precision
If multiple parts and assembly steps are used, then the motor can be manufactured with precise tolerances, but the cost increases
Solution Approach 1:
The patent merges multiple traditional motor components into a simplified structure. The rotor is designed as a single electrically conductive component without laminations, magnets, or windings, while the stator uses simple coils without complex magnetic circuits. This merging reduces the number of parts and assembly steps while maintaining manufacturing precision through fewer interfaces and tolerances to control
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 solution results in a lighter, more cost-effective electric motor with improved responsiveness and speed, capable of providing higher torque and power density, suitable for applications in aircraft and other demanding environments.
Implementation Method 1
The stator coil generates an alternating magnetic field that causes an eddy current in the rotor
Implementation Method 2
The stator coil generates an alternating magnetic field that causes an eddy current in the rotor
Data Source
Figure 1
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AI summary
A method and apparatus for controlling an electric motor. A flow of an alternating current through stator coils in the electric motor is controlled based on a position of a rotor in the electric motor such that a repulsive force between a rotor and a stator coil in the stator coils occurs when the alternating current flows through the stator coil.