Field-Modulated Permanent Magnet Motor Harmonic Coupling Control
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Solution Overview
Problem
The dual-air-gap field-modulated permanent magnet motor experiences magnetic field coupling issues due to the interaction of combined magnetic fields, affecting motor performance and torque density, which existing topological improvements do not fully address.
Innovation Solution
A magnetic field coupling analysis method based on harmonic groups is proposed, involving the calculation of flux density components, coupling effect ratios, and harmonic efficiencies to identify and modulate the magnetic field coupling, improving torque performance by adjusting the contour lines and magnetomotive force of surface-mounted permanent magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a dual-air-gap structure is adopted to improve torque density, then the motor achieves high power density and torque capacity, but magnetic field coupling occurs between the two air-gap magnetic fields, affecting motor performance
Solution Approach 1:
The patent analyzes the magnetic field coupling effect between the two air-gap magnetic fields and identifies that while coupling generally has negative effects, certain coupled harmonics can have positive effects on motor performance. The invention converts the harmful magnetic field coupling into a beneficial effect by selectively utilizing positive coupled harmonics to enhance torque density while mitigating negative impacts through harmonic group analysis and modulation.
Solution Approach 2:
The patent employs harmonic group analysis to identify and modulate specific harmonic components in the magnetic field. By analyzing the coupling effect ratio and harmonic coupling efficiency of different harmonic groups, the invention adjusts magnetic field parameters to optimize the balance between utilizing positive coupled harmonics and suppressing negative ones, thereby resolving the contradiction between torque density improvement and magnetic field coupling mitigation.
2Reliability
If existing topological improvements are implemented to avoid magnetic field coupling, then motor structure is modified, but the coupling of the combined magnetic field cannot be fully acquired and torque performance is not fully optimized
Solution Approach 1:
The patent introduces a feedback mechanism through harmonic group analysis, where the coupling effect ratio and harmonic coupling efficiency are calculated and used to guide further optimization. By continuously analyzing the magnetic field coupling characteristics and adjusting the modulation strategy based on the identified positive and negative coupled harmonics, the invention achieves both stable motor performance and optimized torque capacity.
Solution Approach 2:
The patent employs dynamic modulation of the magnetic field through controllable winding structures and adjustable excitation parameters. This allows the motor to dynamically optimize its magnetic field distribution to maximize the utilization of positive coupled harmonics while minimizing negative effects, thereby achieving both high torque capacity and stable performance without being constrained by fixed topological modifications.
3Power
If the contour lines and magnetomotive force of surface-mounted permanent magnets are adjusted to modulate magnetic field coupling, then positive coupling efficiency is enhanced and negative coupling is reduced, but the design complexity increases
Solution Approach 1:
The patent segments the magnetic field into distinct harmonic groups and analyzes their coupling characteristics separately. By dividing the complex magnetic field interaction into manageable harmonic components, the invention simplifies the modulation process while achieving effective torque optimization. This segmentation approach allows for systematic adjustment of contour lines and magnetomotive force without overwhelming design complexity.
Solution Approach 2:
The patent utilizes parameter changes in the permanent magnet design, specifically adjusting the contour lines and magnetomotive force characteristics to achieve desired harmonic modulation. By focusing on key parameters such as magnet shape factors and excitation amplitudes, the invention achieves effective magnetic field coupling modulation without requiring complex structural modifications, thereby balancing torque performance improvement with design simplicity.
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 method effectively analyzes and modulates the magnetic field coupling, enhancing the positive coupling efficiency and reducing negative coupling, thereby improving the motor's torque capacity and performance by optimizing the harmonic coupling characteristic.
Implementation Method 1
Two air-gap magnetic fields define a combined magnetic field subject to a certain interaction effect
Implementation Method 2
The coupling of the combined magnetic field will affect the coordinated control and mechanical reliability of the motor
Data Source
AI summary
A magnetic field coupling analysis and modulation method for a field-modulated permanent magnet motor based on a harmonic group is provided. The method includes: if a permanent magnet excitation source includes an outer surface-mounted permanent magnet and an intermediate permanent magnet and an armature magnetic source is an outer armature winding, acquiring a normal flux density component of an outer air-gap magnetic field of the motor; if the permanent magnet excitation source includes an inner surface-mounted permanent magnet and the intermediate permanent magnet and the armature magnetic source is an inner armature winding, acquiring a coupled flux density component of the outer air-gap magnetic field; calculating a coupling effect ratio, a harmonic characteristic factor, and a harmonic coupling efficiency in sequence from an air-gap flux density; determining positive and negative coupled harmonics according to the harmonic coupling efficiency; and establishing positive and negative coupled harmonic groups respectively.