Stator Split Core Inductance Control for Aircraft Motor Safety
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Solution Overview
Problem
Electric motors used in aircraft with electric flight controls face challenges in managing short-circuit torque, leading to increased size, mass, and cost due to the need for higher torque compensation, which existing solutions either increase losses or require significant modifications to the magnetic circuit and manufacturing processes.
Innovation Solution
The stator design is adapted by controlling the inductance through a specific arrangement of laminations and decoupling teeth, allowing for adjustable short-circuit torque without altering the manufacturing process, using a conventional tool to achieve a predefined torque suited to the application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motors are sized to compensate for braking force from faulty motors, then safety is improved, but the motor size, mass and cost increase
Solution Approach 1:
The patent adjusts the inductance parameter of the stator by modifying the spacing between laminations to change the motor's short-circuit torque characteristics. This allows the motor to be sized appropriately for the application without requiring excessive torque compensation capability, thereby reducing mass while maintaining safety.
2Force
If the resistance of the coils is increased to limit short-circuit torque, then the maximum torque speed increases, but the Joule losses increase and motor performance degrades
Solution Approach 1:
Instead of changing coil resistance, the patent changes the inductance parameter by adjusting lamination spacing. This modifies the back-EMF constant and torque-speed characteristics without increasing resistive losses, thereby limiting short-circuit torque while maintaining motor efficiency and performance.
3Force
If the flux of the magnets is reduced to limit torque, then the short-circuit torque decreases, but the motor performance decreases and cooling becomes necessary
Solution Approach 1:
The patent changes the inductance parameter through lamination spacing rather than reducing magnet flux. This allows torque limitation while preserving the motor's power output and efficiency characteristics, avoiding the need for additional cooling systems.
4Reliability
If three stators are mounted along the shaft to satisfy safety requirements, then redundancy is improved, but the mass and bulk increase
Solution Approach 1:
By adjusting the inductance parameter of each stator through lamination spacing, the patent enables each motor to be properly sized for its intended duty including fault tolerance requirements. This eliminates the need for redundant motor assemblies, reducing overall mass and bulk while maintaining safety through proper single-motor sizing.
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 approach enables easy adaptation of the motor to a predetermined maximum short-circuit torque, reducing the motor's size, mass, and cost while maintaining performance by limiting magnetic coupling between poles, thus optimizing the motor's design for safety and efficiency.
Implementation Method 1
a bundle of laminations (2) delimiting poles (4), said bundle of laminations comprising a plurality of first laminations (21), each comprising portions (21.1) forming a pole part that are joined by an annular internal portion (21.2), second laminations (22) each forming a pole part that are mounted between the first laminations (21)
Implementation Method 2
The stator (1) comprises decoupling teeth (31.2) extending between the adjacent poles (4)
Data Source
AI summary
An electric motor stator wherein an annular central part and a yoke surrounding the central part, the central part includes a bundle of laminations delimiting poles, wherein the bundle of laminations includes a plurality of first laminations each containing portions forming a pole part that are joined by an annular internal portion, second laminations each forming a pole part being mounted between the first laminations, the first laminations being spaced apart from one another at a predetermined spacing according to a required inductance.