Wind Generator Asymmetric Poles Reduce Cogging Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wind power installations face noise issues due to vibrational excitations caused by slot cogging torques and meshing of teeth, which existing solutions like asymmetric pole arrangements and trapezoidal pole pieces do not fully address.
Innovation Solution
A generator design with a fractional ratio of slots to the product of poles and winding phases (>1 and ≤1.5), where the edges of successive poles or pole groups are oppositely inclined to the axis of rotation, and permanent magnets are integrated with the rotor, reducing cogging torques and vibrational excitations by compensating forces acting on teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If asymmetric pole arrangement is used to reduce slot cogging torques, then noise is reduced, but device complexity increases
Solution Approach 1:
The patent applies asymmetric pole arrangement where the front and rear edges of successive poles or groups of poles are oppositely inclined to the axis of rotation. This asymmetric geometry modifies the magnetic field distribution to reduce slot cogging torques and associated noise while maintaining generator functionality
Solution Approach 2:
The patent specifies a fractional ratio of the number of slots to the product of the numbers of poles and winding phases, where the ratio is greater than 1 and preferably between 1 and 1.5. This parameter optimization works in conjunction with the asymmetric pole arrangement to further reduce cogging torques and noise
2Productivity
If direct drive configuration is used without transmission, then productivity increases, but noise increases due to lack of dampening coupling elements
Solution Approach 1:
The asymmetric pole arrangement with oppositely inclined edges compensates for the lack of mechanical dampening coupling elements by modifying the magnetic field to reduce slot cogging torques, thereby controlling noise directly at the source in direct drive configurations
Solution Approach 2:
The optimized fractional slot-to-pole-phase ratio provides an additional mechanism to reduce cogging torques in direct drive configurations, compensating for the absence of transmission-based noise dampening
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 design effectively suppresses slot cogging torques and vibrational excitations, leading to significant noise reduction in wind power installations, especially when used in direct drive configurations without transmission, where dampening elements are not feasible.
Implementation Method 1
Generator for wind power installations with teeth which are surrounded by windings and separated by slots, and permanent magnets that form the poles of the exciter field
Implementation Method 2
vibrational excitations are suppressed during generator operation by the compensation of forces generated by the poles and acting on the teeth by successive poles or successive groups of poles generating forces opposed to each of the aforesaid forces
Data Source
AI summary
A generator for a wind power has teeth which are surrounded by windings and separated by slots, and permanent magnets that form the poles of the exciter field. The ratio of the number of slots to the product of the numbers of poles and winding phases is fractional and >1. Alternatively or additionally, the front and/or rear edges of successive poles or groups of poles are oppositely inclined to the axis of rotation.