Segmented Motor Rotor with Variable Coercivity Magnets
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Solution Overview
Problem
Traditional permanent magnet motors face challenges in achieving both high-frequency and low-frequency efficiency due to fixed magnetic fields, limiting their operating frequency and flux adjustment range, which results in reduced efficiency during flux intensifying control.
Innovation Solution
The motor rotor design incorporates a specific arrangement of permanent magnets with varying coercivity and dimensions, including a central rotating shaft and flux barrier slots, to enhance flux adjustment range and reduce magnetizing and demagnetizing difficulties, ensuring optimal operating efficiency by maintaining magnetic steel in a flux intensifying state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed magnetic field is provided by permanent magnets, then the motor structure is simple, but the flux adjustment range is limited and operating efficiency at different frequencies deteriorates
Solution Approach 1:
The motor rotor is segmented into multiple independent permanent magnets with different coercivity values arranged in specific patterns. This segmentation allows each magnet to contribute differently to the overall magnetic field, enabling flux adjustment while maintaining structural simplicity.
Solution Approach 2:
Different regions of the rotor are equipped with permanent magnets having locally optimized coercivity properties. High-coercivity magnets provide stable baseline flux, while low-coercivity magnets enable flux adjustment, creating local quality variations that achieve overall flux control capability.
2Reliability
If high-coercivity permanent magnets are used, then magnetic stability is improved, but magnetizing and demagnetizing difficulty increases
Solution Approach 1:
The rotor employs a hybrid configuration where high-coercivity permanent magnets are positioned in regions requiring magnetic stability, while low-coercivity permanent magnets are placed in regions where ease of magnetizing/demagnetizing is prioritized for flux adjustment operations.
Solution Approach 2:
The motor rotor uses a composite arrangement of permanent magnets with different coercivity characteristics, combining high-coercivity and low-coercivity materials in a single system to simultaneously achieve magnetic stability and ease of flux control.
3Adaptability or versatility
If flux weakening control is used to expand operating range, then operating frequency range is increased, but operating efficiency during flux intensifying control deteriorates
Solution Approach 1:
The motor enables dynamic flux adjustment by selectively controlling which permanent magnets are magnetized or demagnetized based on operating conditions. This dynamic control allows the motor to optimize efficiency across different operating frequencies without relying solely on flux weakening control.
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 motor's flux adjustment range, reduces magnetizing and demagnetizing currents, and improves operating efficiency by maintaining magnetic stability and optimizing inductance, thereby enhancing the motor's performance under flux intensifying control.
Implementation Method 1
Magnetic flux is supplied to a traditional permanent magnet motor by a permanent magnet
Implementation Method 2
a magnetic field created by a current of an armature coil magnetizes the first permanent magnet, to irreversibly change a flux amount of the first permanent magnet
Data Source
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AI summary
The present disclosure discloses a motor rotor and a permanent magnet motor. The motor rotor comprises a rotor core (1) and a plurality of magnetic poles provided in the rotor core (1). The magnetic pole comprises a first permanent magnet (2), a second permanent magnet (3), and a third permanent magnet (4), and the size relationship of the first permanent magnet (2), the second permanent magnet (3) and the third permanent magnet (4) in the cross section of the rotor core (1) meets m/2>H1∗Hcj1∗L1/[(H2∗Hcj2∗L2+1/2H3∗Hcj2∗L3)]>m/10, wherein m is a multiple of the motor flux adjustment range; L1 is the length of the first permanent magnet (2); H1 is the width of the first permanent magnet (2); Hcj 1 is the intrinsic coercivity of the first permanent magnet (2); L2 is the length of the second permanent magnet (3); H2 is the width of the second permanent magnet (3); Hcj2 is the intrinsic coercivity of the second permanent magnet (3); L3 is the length of the third permanent magnet (4); H3 is the width of the third permanent magnet (4); and Hcj3 is the intrinsic coercivity of the third permanent magnet (4). With the described motor rotor, the magnetizing and demagnetizing difficulty can be effectively reduced, the motor flux adjustment range is increased, and the operating efficiency of the motor in flux intensifying control is improved.