Rotor Interlocking Elements for Low-Torque-Ripple Laminations
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Solution Overview
Problem
Synchronous reluctance motors (SynRM) and permanent magnet assisted synchronous reluctance motors (PMASynRM) experience high ripple torque at high and low speeds due to the presence of internal bridges in the rotor lamination stack, which reduces motor performance and mechanical strength.
Innovation Solution
The introduction of non-metallic and non-magnetic interlocking elements within the barriers of the rotor lamination stack, which are strategically designed to match the curves and edges of the barriers, allowing them to be positioned within the barriers and reducing torque ripple without compromising mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If internal bridges are added to rotor laminations to reduce mechanical stresses, then mechanical strength is improved, but torque ripple increases at high and low speeds
Solution Approach 1:
The patent removes internal bridges from the rotor lamination stack, extracting the harmful element that caused torque ripple while maintaining mechanical strength through alternative design configurations of the laminations themselves
Solution Approach 2:
The patent modifies the geometric parameters of the rotor laminations, including the shape and positioning of magnetic poles and air gaps, to optimize both mechanical strength and torque characteristics without requiring internal bridges
2Power
If complex rotor designs with strategic magnetic reluctance regions are implemented to achieve desired torque production, then torque production is improved, but device complexity increases
Solution Approach 1:
The rotor is segmented into multiple laminations with specific magnetic pole configurations, allowing complex magnetic reluctance patterns to be achieved through simple, repeatable modular units that reduce overall design complexity
Solution Approach 2:
Different regions of the rotor lamination are given different magnetic properties through selective material orientation and pole configuration, creating strategic high and low reluctance zones without requiring complex overall structure
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 effectively reduces torque ripple and pulsing radial forces at various operating speeds, maintaining mechanical strength and potentially lowering manufacturing costs by simplifying the rotor design.
Implementation Method 1
Rotor reluctance depends on empty regions of the lamination that comprise magnetically insulating materials, such as air. The empty regions, henceforth called barriers, may create magnetic barriers where magnetic flux encounters high resistance (e.g., high reluctance) that may hinder flow of the magnetic field.
Data Source
AI summary
Methods and systems are disclosed for reducing ripple torque associated with internal bridges arranged within one or more barriers of a rotor lamination stack and increasing mechanical strength when the rotor lamination stack is configured without internal bridges. In one example, a rotor lamination stack includes at least one interlocking element arranged in one or more barriers. In another example, the at least one interlocking elements may be fabricated individually and independent of the rotor lamination stack or by employing the rotor lamination stack as a mold.