Variable-Field Rotary Machine Axial Iron Core Displacement
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Solution Overview
Problem
Existing variable-field rotary electric machines face challenges with increased core loss and field-weakening ohmic loss during high-speed rotation, and their size becomes larger due to complex structures when trying to adjust the magnetic field.
Innovation Solution
A variable-field rotary electric machine with a simple structure that includes a rotor with a movable iron core and a displacement mechanism using a cylinder unit filled with hydraulic fluid, which displaces the iron core axially in response to changes in rotor speed, allowing for easy adjustment of the magnetic field and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the interlinkage magnetic flux of magnets is enlarged to increase torque density during low speed rotation, then torque density is improved, but core loss increases during high-speed rotation
Solution Approach 1:
The iron core is made movable along the axial direction and its position is dynamically adjusted based on rotation speed. At low speeds, the iron core is positioned to maximize interlinkage magnetic flux and torque density. At high speeds, the iron core is repositioned to reduce magnetic flux and minimize core loss, enabling the system to adapt optimally to different operating conditions
Solution Approach 2:
The invention changes the physical position parameter of the iron core along the axial direction to control the magnetic field characteristics. By adjusting the iron core's axial position, the interlinkage magnetic flux is varied, allowing optimization of torque density at low speeds and reduction of core loss at high speeds
2Loss of energy
If a wire traction device is used to pull the stator off the rotor to decrease magnetic flux and reduce core loss, then core loss is reduced, but the structure becomes more complex
Solution Approach 1:
The invention extracts and eliminates the complex wire traction device from the system. Instead of using wires to mechanically pull the stator off the rotor, the patent employs a simpler hydraulic cylinder mechanism that directly moves the iron core along the axial direction, achieving the same magnetic flux control function with reduced structural complexity
Solution Approach 2:
The invention introduces a hydraulic cylinder mechanism to replace the mechanical wire traction device. The hydraulic cylinder uses fluid pressure to move the iron core axially, providing a more compact and simpler structure compared to the wire-based mechanical traction system, while achieving the same purpose of adjusting magnetic flux
3Adaptability or versatility
If the stator is pulled off the rotor to adjust the magnetic field, then the magnetic field is adjusted, but the device size increases
Solution Approach 1:
The hydraulic cylinder mechanism is integrated within the existing rotor structure, with the iron core moving within the rotor's axial space. This nested arrangement allows magnetic field adjustment functionality to be incorporated without significantly increasing the overall device volume, maintaining compactness while achieving adaptability
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 solution effectively reduces core loss, allows for easy magnetic field adjustment, and results in a more compact rotary electric machine, suitable for use in vehicles.
Implementation Method 1
a cylinder unit including a cylinder chamber to retain hydraulic fluid according to a rotor speed, a piston member connected to the movable iron core, and a sealer member provided at the piston member. The the piston member and the movable iron core are displaced in the axial direction of the rotation shaft in response to an increase or decrease in an amount of the hydraulic fluid in the cylinder chamber
Data Source
AI summary
The variable-field rotary electric machine includes: a rotor that is rotatably integrated with a shaft while an axis of the shaft is used as a rotation axis and includes a movable iron core and a displacement mechanism configured to displace the movable iron core in an axial direction of the rotation shaft. The displacement mechanism includes: a cylinder unit including a cylinder chamber to retain hydraulic fluid according to a rotor speed, a piston member connected to the movable iron core, and a sealer member provided at the piston member. The the piston member and the movable iron core are displaced in the axial direction of the rotation shaft in response to an increase or decrease in an amount of the hydraulic fluid in the cylinder chamber.