Variable Flux Motor Segmented Rotor Design
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Solution Overview
Problem
Existing variable flux motors are costly due to the use of high-priced permanent magnets and complex stator configurations, with inefficiencies in magnetization and demagnetization processes.
Innovation Solution
A variable flux motor design featuring a stator and rotor with a fixed magnet and a variable magnet of lower coercive force, arranged radially and circumferentially, along with inter-magnet and variable magnet flux barriers, to enhance magnetization and demagnetization efficiencies, reducing the number of permanent magnets and fabrication complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-priced permanent magnets with high coercive force are used in variable flux motors, then magnetic flux stability is improved, but fabricating cost increases
Solution Approach 1:
The rotor magnet system is segmented into two distinct parts: fixed magnets with high coercive force that provide stable magnetic flux, and variable magnets with lower coercive force that can be easily magnetized and demagnetized. This segmentation allows each type of magnet to perform its specific function optimally while reducing overall costs by using cheaper variable magnets in controlled positions.
Solution Approach 2:
Different regions of the rotor are assigned different magnetic properties: the fixed magnets maintain high coercive force for stability, while the variable magnets have lower coercive force for controllability. This local differentiation of magnetic properties enables the motor to achieve both stability and variable flux control without uniformly using expensive high-coercive-force magnets throughout.
2Ease of manufacture
If variable magnets with lower coercive force are used, then fabricating cost is reduced, but magnetization and demagnetization efficiency decreases
Solution Approach 1:
A flux barrier is introduced as an intermediary element between the variable magnets and the stator. This flux barrier concentrates and directs the magnetic flux generated by the variable magnets, improving the efficiency of magnetization and demagnetization processes. The flux barrier ensures that even with lower coercive force magnets, the magnetic flux is effectively utilized.
Solution Approach 2:
The coercive force parameter of the magnets is strategically reduced for the variable magnets, allowing easier magnetization and demagnetization. This parameter change is compensated for by the flux barrier design that optimizes flux concentration, thereby maintaining overall system efficiency despite using lower coercive force materials.
3Reliability
If complex stator configurations with ears and grooves are implemented, then magnetic flux control is improved, but device complexity increases
Solution Approach 1:
The flux control function previously requiring complex stator ears and grooves is extracted and relocated to the rotor side through the flux barrier design. This extraction simplifies the stator structure by removing unnecessary complex features while maintaining effective magnetic flux control through the rotor-mounted flux barrier.
Solution Approach 2:
Instead of implementing flux control features in the stator (ears and grooves), the invention inverts the approach by placing the flux control mechanism (flux barrier) in the rotor. This inversion simplifies the stator structure while achieving the same or better flux control performance through the rotor-side flux barrier.
4Power
If multiple permanent magnets are arranged on the same circumference, then magnetic flux density is improved, but fabricating cost increases
Solution Approach 1:
The magnet arrangement is segmented into fixed magnets and variable magnets positioned at specific locations. This segmentation allows concentrated flux density where needed (near the stator) while using fewer overall magnets, reducing material costs. The fixed magnets provide baseline flux density, while variable magnets provide controlled flux enhancement.
Solution Approach 2:
The coercive force parameter is differentiated between fixed and variable magnets, allowing the use of lower-cost variable magnets in specific positions. This parameter differentiation enables cost-effective magnet selection while maintaining adequate flux density through strategic positioning and the flux barrier concentration effect.
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 reduces fabrication costs, improves torque control by varying magnetic flux, and enhances operation efficiency across different speed zones by magnetizing and demagnetizing the variable magnet using the stator coil.
Implementation Method 1
a magnetic flux of the variable magnet varies when a preset current is applied to the stator coil
Implementation Method 2
an electric motor is an apparatus that converts electric energy into mechanical energy
Data Source
AI summary
The present invention relates to a variable-flux motor comprising: a stator having stator coils; and a rotor disposed to be rotatable with respect to the stator with an air gap interposed therebetween, wherein the rotor comprises: a rotor core; a fixed magnet disposed along the radial direction of the rotor core, and of which one end portion is disposed adjacently to the air gap; and a variable magnet disposed inside the fixed magnet along the radial direction of the rotor core, and the variable magnet is formed such that a magnetic flux thereof varies when a preset current is applied to the stator coils. Therefore, use of an expensive permanent magnet can be excluded.