Bi-Magnet Rotor Cavities for Torque and Cost Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional permanent magnet synchronous motors using rare earth magnets are costly due to their high price, which increases the overall motor cost without effectively optimizing torque and rotational speed.
Innovation Solution
The use of bi-permanent magnets with different magnetic field strengths, such as a combination of rare earth and ferrite magnets in a multilayer structure within the rotor, where the lesser magnetic strength magnets extend at least half the radial distance between the outer and inner cylinder walls to enhance torque and rotational speed, reducing the need for rare earth magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rare earth magnets are used in the rotor, then magnetic field strength and torque are improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent applies local quality by using different magnet materials in different regions of the rotor. High-strength rare earth magnets are placed only in the first layer where maximum magnetic field strength is needed, while lower-cost ferrite magnets are used in the second layer. This regional differentiation maintains necessary magnetic performance while reducing overall material cost.
Solution Approach 2:
The patent employs composite materials by combining two types of permanent magnets (rare earth and ferrite) with different magnetic properties in a multilayer configuration. This composite approach allows the rotor to achieve adequate magnetic field strength through the combination of materials rather than using expensive rare earth magnets throughout the entire structure.
2Ease of manufacture
If the number and mass of rare earth magnets are reduced, then manufacturing cost decreases, but magnetic field coverage and torque may be compromised
Solution Approach 1:
The patent transitions from a single-layer magnet configuration to a multilayer three-dimensional structure. By stacking multiple layers of V-shaped cavities with permanent magnets and extending magnets radially across different depths, the design achieves comprehensive magnetic field coverage throughout the rotor volume, maintaining torque production while using fewer rare earth magnets.
Solution Approach 2:
The patent segments the rotor magnet structure into multiple discrete layers and V-shaped cavity units. Each layer contains multiple V-shaped cavities with permanent magnets arranged in specific patterns. This segmentation allows optimized placement of rare earth magnets in critical areas while using cheaper materials in less critical regions, balancing cost and performance.
3Ease of manufacture
If a multilayer structure with bi-permanent magnets is used, then cost is reduced and magnetic field coverage is improved, but rotor structure complexity increases
Solution Approach 1:
The patent merges multiple functional elements into an integrated multilayer structure. The V-shaped cavities, permanent magnets, and rotor core are combined into a unified assembly where layers are stacked and interconnected. This merging reduces the number of separate components and assembly steps despite the increased internal complexity, making the design more 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
This configuration reduces the overall cost of the motor by minimizing the use of high-cost rare earth magnets while increasing torque and rotational speed through a substantial magnetic field coverage across the rotor.
Implementation Method 1
A permanent magnet synchronous motor is an AC motor in which rotation rate of the shaft is synchronized with the frequency of the AC supply current. A rotating electric field is generated in the stator and the rotor follows the rotating electrical field of the stator.
Implementation Method 2
The permanent magnets used in conventional rotors are configured to provide a uniform field strength. Neodymium magnets, also known as rare earth magnets, are often desired due to their strong magnetic field strength which provides enhanced torque in motors.
Data Source
AI summary
A rotor for a permanent magnet synchronous machine. A first layer of cavities formed circumferentially within the rotor core structure. Pairs of the cavities in the first layer form V-shaped configurations and are spaced circumferentially about the rotor core structure in the first layer. A second layer of cavities is formed circumferentially within the rotor core structure. Pairs of the cavities in the second layer form V-shaped configurations and are spaced circumferentially about the rotor core structure in the second layer. A first set of permanent magnets is inserted within each cavity in the first layer and a second set of permanent magnets inserted within each cavity in the second layer. Each respective V-shaped configuration of the second layer having permanent magnets disposed therein extend greater than half a radial distance from the outer cylindrical wall to the inner cylindrical wall.