IPM Rotor Magnet Geometry Optimization for Torque
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Solution Overview
Problem
The performance of interior permanent magnet synchronous motors is limited by the restricted use of rare-earth permanent magnets, which are non-renewable and expensive, and the limited volume of the rotor restricts the increase in output torque and efficiency.
Innovation Solution
The motor rotor design includes an iron core with permanent magnets arranged in specific mounting grooves, optimizing the length and width of the magnets to increase magnetic flux and torque without increasing the usage of permanent magnets, thereby enhancing the motor's efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If rare-earth permanent magnets are used to increase permanent magnet torque, then motor efficiency is improved, but cost increases and resource sustainability deteriorates
Solution Approach 1:
The patent changes the geometric parameters of permanent magnets, specifically optimizing the ratio of width to length (H/L) to be 0.5-1.5. This parameter optimization increases the magnetic flux density and utilization rate of the permanent magnets, thereby improving motor efficiency without increasing the quantity of rare-earth materials used.
Solution Approach 2:
The patent divides the permanent magnet arrangement into multiple mounting grooves with different orientations (first mounting grooves along the radial direction, second mounting grooves along the tangential direction). This segmentation allows for optimized magnetic flux distribution and increased torque output without requiring additional permanent magnet material.
2Power
If the volume of permanent magnets is increased to increase output torque, then motor performance is improved, but the limited rotor volume is exceeded
Solution Approach 1:
The patent optimizes the geometric parameters of permanent magnets, specifically the width-to-length ratio (H/L = 0.5-1.5), to maximize magnetic flux density and utilization. This allows achieving higher output torque within the existing rotor volume constraints without physical expansion of the rotor.
Solution Approach 2:
The patent introduces a new dimensional arrangement by creating multiple groups of mounting grooves with different orientations (radial and tangential directions). This multi-dimensional arrangement of permanent magnets maximizes the use of available rotor space and increases torque output without increasing rotor volume.
3Power
If the occupation ratio of permanent magnets in each pole is increased, then permanent magnet torque is improved, but the limited rotor space restricts further increase
Solution Approach 1:
The patent segments the permanent magnet arrangement into multiple mounting grooves with different orientations within each pole. This includes first mounting grooves extending along the radial direction and second mounting grooves extending along the tangential direction, allowing optimized magnetic flux distribution without excessive complexity.
Solution Approach 2:
The patent applies different geometric configurations of permanent magnets in different local regions (different mounting grooves with different orientations) to optimize magnetic flux distribution locally, thereby maximizing permanent magnet torque while maintaining manageable overall complexity.
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 increases the utilization rate of permanent magnets, improving motor efficiency and reducing the need for rare-earth materials, leading to cost savings and environmental benefits.
Implementation Method 1
An interior permanent magnet synchronous motor (IPM) is a motor having a layer of permanent magnet placed inside a rotor and primarily utilizing permanent magnet torque and utilizing auxiliary reluctance torque
Implementation Method 2
the air-gap magnetic flux density of the permanent magnetic may be increased effectively
Implementation Method 3
a plurality of groups of permanent magnets are provided, and permanent magnets in each group of permanent magnets are correspondingly embedded into corresponding mounting grooves
Data Source
AI summary
A motor and a rotor thereof are provided. Taking the distance between the two endpoints of a permanent magnet of a motor rotor that are on the side away from the center of an iron core as the length L of the permanent magnet, and the distance between a line connecting the two endpoints of the permanent magnet that are on the side away from the center of the iron core and the center point on the side of the permanent magnet that is close to the centerline of the iron core as the width H of the permanent magnet, then H/L ≧ 1/10. By adjusting the relationship between the length L and width H of the permanent magnet, the air gap magnetic density of the permanent magnet can be effectively increased.