Variable Flux Permanent Magnet Motor Design
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Solution Overview
Problem
Conventional permanent magnet motors experience reduced efficiency due to constant magnetic flux, which is not optimized for varying speed and torque conditions, particularly in automotive applications where efficiency is critical.
Innovation Solution
A permanent magnet motor design with at least two states of magnetic flux, utilizing permanent magnets with different coercivity levels and a magnetic field generator to adjust the magnetization of the second magnet, allowing for varying magnetic flux based on speed, thereby optimizing efficiency across different speed ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If constant magnetic flux is used in permanent magnet motors, then the motor structure is simple and reliable, but the efficiency is reduced under varying speed and torque conditions
Solution Approach 1:
The patent applies the dynamics principle by making the magnetic flux variable rather than constant. The motor controller dynamically adjusts the magnetization state of the permanent magnets based on operating conditions (speed and torque), allowing the magnetic flux to change from a static property to a dynamic one that adapts to varying operational requirements, thereby improving efficiency across different speed ranges.
Solution Approach 2:
The patent implements parameter changes by modifying the magnetic flux parameter of the permanent magnets. By changing the magnetization level of the permanent magnets from a fixed state to a variable state controlled by the controller, the motor can optimize its magnetic flux parameter according to operating conditions, resolving the contradiction between maintaining simple structure and achieving adaptability.
2Adaptability or versatility
If permanent magnets with low coercivity are used to enable variable flux, then the motor can adjust magnetic flux for improved efficiency, but the magnets become more susceptible to demagnetization
Solution Approach 1:
The patent employs feedback control through the motor controller that monitors operating conditions and adjusts the magnetization state of permanent magnets accordingly. This feedback mechanism ensures that magnets are only demagnetized or remagnetized when necessary and appropriate, preventing unnecessary exposure to demagnetization risks while maintaining the ability to adjust flux for efficiency optimization.
Solution Approach 2:
The patent introduces an intermediary control system (the motor controller) that mediates between the permanent magnets and the magnetic field requirements. This intermediary manages the magnetization/demagnetization process carefully, applying controlled magnetic fields only when needed to achieve desired flux levels, thereby protecting the magnets from unnecessary demagnetization while enabling variable flux operation.
3Loss of energy
If variable flux is implemented in permanent magnet motors, then efficiency improves under varying speed conditions, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent applies universality by designing the motor controller to perform multiple functions: it controls the stator windings for motor operation and simultaneously controls the magnetization state of permanent magnets. This multi-functional approach allows the same control system to manage both the electromagnetic field generation and the permanent magnet flux adjustment, reducing the need for separate dedicated control mechanisms and thereby limiting the increase in device 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
The motor achieves improved efficiency by adjusting magnetic flux according to speed, enhancing performance in variable speed applications and potentially extending the motor's speed range, while also providing a mechanism for safer shutdown and easier assembly.
Implementation Method 1
The permanent magnets are then attracted to and/or repelled by a rotating magnetic field from the stator of the motor to rotate the rotor
Implementation Method 2
a rotating magnetic field from the stator of the motor to rotate the rotor
Implementation Method 3
at least one permanent magnet with a relatively low coercivity that allows magnetization of the magnet to be changed while the motor is in use
Implementation Method 4
a magnetic field generator to adjust the magnetization of the second magnet
Data Source
AI summary
A permanent magnet motor is provided that produces variable magnetic flux. The motor may include two different types of permanent magnets with different coercivities. The magnetic state of one of the magnets may be altered during use. In one state, the effective magnetic flux of the motor is greater, and in another state, the effective magnetic flux of the motor is less.