Permanent Magnet Rotating Device Cogging Torque Minimization
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Solution Overview
Problem
Permanent magnet generators and motors face challenges with high cogging torque, which leads to vibration, noise, and reduced efficiency, and existing methods to minimize cogging torque often decrease output and increase manufacturing costs.
Innovation Solution
A permanent magnet rotating device with a specific combination of poles and slots, optimized spacing of permanent magnets, and a winding method that balances magnetic fields to minimize cogging torque while maintaining output and efficiency, using equations to determine the number of poles, slots, and turns of coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional methods for reducing cogging torque (skewing, tooth machining) are applied, then cogging torque is reduced, but manufacturing costs increase
Solution Approach 1:
The patent changes the geometric parameters of the permanent magnets (width, height, spacing) and the stator slots to optimize the magnetic field distribution. By adjusting these parameters, the cogging torque is reduced without requiring additional manufacturing processes like skewing or tooth machining, thus avoiding increased manufacturing costs.
Solution Approach 2:
The patent employs asymmetric arrangement of permanent magnets with different widths and heights, and asymmetric slot designs in the stator. This asymmetric configuration creates a more balanced magnetic field distribution that reduces cogging torque while maintaining simple manufacturing processes.
2Power
If radial flux permanent magnet generators with slots are used, then output voltage and efficiency are high, but cogging torque is high causing vibration and noise
Solution Approach 1:
The patent optimizes the parameters of permanent magnets (width w1, height h1, spacing s1) and stator slots to achieve a balanced magnetic field. This parameter optimization reduces cogging torque and associated vibration and noise while preserving the high output voltage and efficiency characteristics of radial flux permanent magnet generators with slots.
Solution Approach 2:
The patent converts the potentially harmful cogging torque into a beneficial force by optimizing the magnetic field distribution. The asymmetric permanent magnet arrangement creates a more uniform magnetic field that reduces the pulsating torque components, thereby converting the harmful cogging effect into a smoother operating condition while maintaining high power output.
3Object-generated harmful factors
If coreless axial flux or slot-less radial flux generators are used to minimize cogging torque, then cogging torque is reduced, but output voltage and efficiency decrease due to high magnetic flux leakage
Solution Approach 1:
The patent changes the geometric parameters of permanent magnets and stator slots to optimize magnetic field confinement. By adjusting the width, height, and spacing of permanent magnets along with corresponding slot dimensions, the magnetic flux leakage is minimized while cogging torque is reduced, achieving both low harmful effects and high power output in a single integrated design.
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 reduces cogging torque, enabling easier initial driving and operation of permanent magnet motors, maximizing output and efficiency without increasing manufacturing costs, and allowing for line-start operation without additional drivers or inverters.
Implementation Method 1
a permanent magnet rotating device having a minimized cogging torque, the permanent magnet rotating device including: a shaft 110; a rotor 200 in which a shaft is coupled to the center thereof and a plurality of permanent magnets 210 are formed at a specific interval; and a stator core 300 having a plurality of slots 310 formed at a specific interval and having slots on which coils are wound
Data Source
AI summary
The inventive concept relates to a permanent magnet rotating device having a minimized cogging torque, a permanent magnet generator using the same, and a motor, and more particularly, an objective of the inventive concept is to minimize a cogging torque of a permanent magnet rotating device including a stator and a rotor used in a motor or a generator by a simple combination of the number of poles and the number of slots and a proper arrangement of permanent magnets without using various conventional methods for reducing cogging torque while increasing costs. Through the inventive concept, cogging torque is minimized when a combination of the number of poles and the number of slots are adjusted, the width of lower ends of slots and a spacing distance between the permanent magnets are made the same, and a proper winding method and a pitch are applied.