Solid Iron Stator Back Iron for EMA Damping
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Solution Overview
Problem
Conventional stators in AC motors for electromechanical actuators require additional damping devices to oppose drag torque, which increases the motor's volume and size, and existing methods to prevent induced currents are inefficient.
Innovation Solution
A solid piece of iron or iron alloy is used to form the stator back iron, allowing induced currents to provide damping, eliminating the need for external damping devices and reducing volume and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional damping devices are added to provide damping function, then damping performance is improved, but motor volume increases
Solution Approach 1:
The damping function is merged with the stator back iron by using solid iron material that allows induced currents. The back iron itself becomes the damping device, eliminating the need for separate damping components and reducing overall motor volume.
Solution Approach 2:
The solid iron back iron performs multiple functions: it provides the structural support of the stator, conducts magnetic flux, and simultaneously provides damping through induced currents. This multi-functionality eliminates the need for dedicated damping devices.
2Loss of energy
If laminated iron alloy sheets are used to prevent induced currents, then energy losses are reduced, but damping function requires additional devices
Solution Approach 1:
Instead of preventing induced currents as in conventional laminated structures, this invention allows induced currents to flow in the solid iron back iron. The induced currents are harnessed to provide the damping function, inverting the conventional approach to induced current management.
Solution Approach 2:
The induced currents that would normally cause energy losses in conventional motors are converted into a beneficial damping effect. The solid iron structure allows these currents to flow and create the desired damping torque, turning a potential harm into a useful function.
3Device complexity
If solid iron material is used for back iron to enable induced currents, then damping function is integrated, but manufacturing complexity increases
Solution Approach 1:
The solid iron back iron is divided into circumferential segments that can be manufactured separately and then assembled. This segmentation makes manufacturing easier while maintaining the solid iron structure needed for integrated damping functionality.
Solution Approach 2:
The material parameters of the iron alloy are optimized to balance damping performance with manufacturability. The specific composition and properties are adjusted to enable both the desired damping effect and practical manufacturing processes.
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
The solution effectively integrates damping within the motor, reducing size and manufacturing time while improving thermal performance at low speeds.
Implementation Method 1
forming the stator back iron of a solid piece of iron material or iron alloy... creates or allows induced currents thus providing a damping function
Implementation Method 2
Pure iron can be used for the solid back iron component(s). Such a material has a high saturation point, high conductivity...
Data Source
AI summary
The present invention goes away from conventional teaching and provides a stator having a construction that creates or allows induced currents thus providing a damping function. This effect is provided by forming the stator back iron of a solid piece of iron material or iron alloy as opposed to a stack of laminations or compressed powder.