Switched Reluctance Machine Pole Configuration for Torque Ripple Reduction
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Solution Overview
Problem
Conventional switched reluctance machines (SRMs) suffer from high torque ripple, low torque density, and vibration due to their design, which limits their efficiency and performance in various applications.
Innovation Solution
The design of SRMs with an even number of stator poles per phase, where the number of rotor poles and stator poles are symmetrically disposed and configured according to specific equations based on the number of phases, pole-phase index, and configuration index, using soft magnetic materials, and employing a symmetrical and evenly distributed stator and rotor pole construction to reduce torque ripple and enhance torque density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional switched reluctance machines use concentrated windings around each stator pole, then the machine can generate electromagnetic field and operate, but it suffers from high torque ripple, low torque density, vibration and acoustic noise
Solution Approach 1:
The patent divides the concentrated winding into multiple distributed coils arranged around each stator pole. Instead of one large coil, multiple smaller coils are distributed spatially, which segments the magnetic field generation process and reduces the harmonic content that causes torque ripple while maintaining the overall electromagnetic field strength
Solution Approach 2:
The patent applies different winding configurations to different stator poles based on their local position and function. Each phase has coils distributed around specific poles with optimized turn ratios and connection patterns, creating locally optimized magnetic fields that reduce overall torque ripple while maintaining high torque density
2Power
If conventional switched reluctance machines use concentrated windings, then the structure is simpler, but the torque density is low and vibration is high
Solution Approach 1:
The patent creates a universal winding configuration that serves multiple functions simultaneously: the distributed coils generate the main electromagnetic field, reduce torque ripple through spatial distribution, minimize vibration through symmetric arrangement, and provide flexible connection options for different phase configurations. This multi-functional design achieves high torque density without proportionally increasing complexity
3Power
If the number of stator poles and rotor poles follows conventional ratios, then the machine operates, but it produces high torque ripple and low torque density
Solution Approach 1:
The patent systematically varies key parameters including the number of stator poles per phase, the number of rotor poles, the distribution of coils around each pole, and the connection patterns between coils. By optimizing these parameters together rather than individually, the patent achieves a configuration that maximizes torque density while minimizing torque ripple through improved magnetic field distribution
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 results in lower manufacturing costs, reduced torque ripple, higher torque density, and improved performance characteristics, such as increased strokes per mechanical revolution and reduced implementation costs, while maintaining efficient torque production.
Implementation Method 1
a plurality of coils provided around the predetermined number of stator poles to form at least one phase of the switched reluctance machine, the plurality of coils adapted to carry electric current to generate magnetic flux
Implementation Method 2
torque is produced by the tendency of the movable part of the machine to move into a position where the inductance of an excited winding is maximized
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 comprises a stator including a predetermined number of salient stator poles (Ns), a rotor rotatably mounted with respect to the stator, with the rotor comprising a plurality of salient rotor poles, and a plurality of coils provided around the predetermined number of stator poles to form at least one phase of the switched reluctance machine, where the rotor poles and the stator poles are symmetrically disposed, and a number of rotor poles is related to 0□ and a number of phases according to: i) (Ns/m)k ceil (mod(k,m)/m) number of phases, and ii) (Ns/m)k ceil (mod(k,m/2)/m/2) for an even number of phases, where m is the number of phases, and k is a configuration index based on Ns and m.