Rotor Assembly Arc-Trimming Depth Optimization
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Solution Overview
Problem
Conventional permanent magnet motors face challenges in balancing the arc depth, magnet position, and rib size to maintain optimal torque performance while minimizing torque ripple, leading to increased design complexity and difficulty in calculating optimal rotor dimensions.
Innovation Solution
The rotor assembly features a main-body portion with magnet-receiving slots and arc-trimming portions, optimized to maintain a specific arc-trimming depth and interval, which reduces torque ripple to less than 10% and improves output torque performance by minimizing the magnetic component thickness and input current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a flower-petal-shaped rotor design is used to improve torque and reduce cogging torque, then output torque performance is improved, but design complexity increases due to the need to balance multiple parameters (arc depth, magnet position, rib size)
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between rotor parameters (arc-trimming depth, slot width, air gap width) to optimize torque performance. The arc-trimming depth is set within a specific range (0.05-0.15 times the slot width) and the arc-trimming interval is set to 0.5-2 times the minimum air gap width, transforming the complex multi-parameter balancing problem into a standardized parameter selection process based on the slot width and air gap width.
2Power
If simulation analysis is used to balance torque performance and torque ripple, then optimal performance can be achieved, but development time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-establishing the optimal parameter ranges through theoretical analysis and experimental validation. The arc-trimming depth range (0.05-0.15 times slot width) and arc-trimming interval range (0.5-2 times minimum air gap width) are determined in advance, allowing designers to directly select optimal parameters without performing extensive simulation analyses during the design process.
3Object-generated harmful factors
If rotor dimensions are optimized to reduce torque ripple, then torque ripple is suppressed, but calculating optimal size becomes more difficult due to mutual influence of dimensional parameters
Solution Approach 1:
The patent transforms the complex multi-parameter optimization problem into a simplified parameter selection process by establishing that the arc-trimming depth should be 0.05-0.15 times the slot width and the arc-trimming interval should be 0.5-2 times the minimum air gap width. This parameter transformation approach eliminates the need for complex iterative calculations while ensuring torque ripple is reduced to less than 10%.
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 torque ripple, enhances motor efficiency, and simplifies the design process by optimizing rotor parameters, resulting in improved anti-demagnetization endurance and reduced input current requirements.
Implementation Method 1
The rotor is rotated by the magnetic force generated between the stator and the rotor
Data Source
AI summary
A rotor assembly for a motor is disclosed. The motor has a minimum air gap width value. The rotor assembly includes magnets, a main-body portion, magnet-receiving slots and arc-trimming portions. Each of the magnet-receiving slots is disposed around a central axis of the main-body portion and locates through the main-body portion for accommodating the corresponding magnet therein. The magnet-receiving slot has a slot width value. The arc-trimming portions spatially correspond to the magnet-receiving slots. Each of the arc-trimming portions and a geometric symmetry center of the corresponding magnet-receiving slot together form an arc-trimming depth value. The arc-trimming depth value is greater than a sum value of a rate constant multiplied by the slot width value and then subtracted 2 times of the minimum air gap width value, and is less than the sum value of the rate constant multiplied by the slot width value and then plus 2 times of the minimum air gap width value.