Multi-Teeth Switched Reluctance Motor Flux Path Reduction
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Solution Overview
Problem
Conventional switched reluctance machines (SRMs) with concentrated windings exhibit long flux paths and increased core losses due to their conventional configurations, which hinder enhanced torque performance.
Innovation Solution
A multi-teeth switched reluctance machine design is implemented with an axially extending shaft and rotor, and an axially extending stator with salient poles and teeth, where the number of stator poles, rotor poles, and phases are related by specific constraints to create shorter flux paths, including a greater distance between adjacent rotor poles and specific angle relationships, optimizing the configuration to reduce core losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional concentrated windings are used in SRM, then the structure is simple and ease of manufacture is improved, but flux path length increases and core losses increase
Solution Approach 1:
The stator is segmented into multiple teeth with specific arc length constraints, dividing the flux path into shorter segments. Each tooth has an arc length less than the arc length between adjacent rotor poles, creating multiple discrete flux paths that are shorter individually, thereby reducing overall core losses while maintaining manufacturability through modular tooth structures
Solution Approach 2:
The patent changes critical geometric parameters including setting the number of stator teeth Nt equal to the number of rotor poles Nr, constraining stator tooth arc length to be less than rotor pole arc length, and specific relationships between stator slot angles and rotor slot angles. These parameter changes optimize flux path length and distribution, reducing core losses while maintaining conventional winding simplicity
2Ease of manufacture
If conventional SRM configuration is used, then manufacturing is simpler, but torque performance is limited due to long flux paths
Solution Approach 1:
By segmenting the stator into multiple teeth with optimized arc lengths, the flux paths are divided into shorter, more efficient segments. This segmentation creates better magnetic coupling between stator and rotor poles, enhancing torque production per unit of current while maintaining the simplicity of conventional concentrated windings
Solution Approach 2:
The patent introduces asymmetric angular relationships between stator and rotor features, with specific constraints on stator tooth arc length versus rotor pole arc length, and specific relationships between stator slot angles and rotor slot angles. This asymmetric design optimizes the magnetic interaction for enhanced torque performance while keeping the overall structure manufacturable
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 optimized configuration results in reduced core losses and improved torque performance by minimizing flux path length, enhancing the efficiency of the SRM.
Implementation Method 1
electrical machines establish and control electromagnetic fields to create the desired electromagnetic performance
Implementation Method 2
the electromagnetic torque is produced by the magnetic attraction of the steel rotor to steel electromagnets
Implementation Method 3
conventional configurations of SRMs have conventional concentrated windings that may result in long flux paths and increased core losses
Implementation Method 4
SRM operates based on varying reluctance
Data Source
AI summary
Various embodiments are described herein for switched reluctance machine configurations. In at least one embodiment, a switched reluctance machine configured according to the teachings herein includes an axially extending shaft, an axially extending rotor mounted to the shaft, the rotor having a plurality of salient rotor poles, an axially extending stator disposed coaxially and concentrically with the rotor, the stator having a plurality of salient stator poles protruding radially from the stator towards the rotor poles, a plurality of stator teeth and tooth-tips, and a plurality of electrical coils wound about the stator poles to define a plurality of phases of the switched reluctance machine, where a number of stator poles can be determined according to the following equation and at least one constraint condition:Ns=Nt×LCM(Ns,Nr)Nr×Nph×S1×S2.