Electrical Machine Rotor Segmentation for Magnet Reduction
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Solution Overview
Problem
Electrical machines with permanent magnets are costly due to the high proportion of magnets in their composition, and existing designs struggle to optimize efficiency effectively.
Innovation Solution
The electrical machine design incorporates a rotor with a unique arrangement of magnets and recesses, allowing for a reduced number of magnetic pole pairs compared to electromagnetic pole pairs, utilizing higher harmonic components of the magnetomotive force for torque generation, and incorporating electromagnets to adjust magnetic fields for enhanced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If permanent magnets are used to generate rotor magnetic field, then efficiency optimization is improved through multiple arrangement possibilities, but manufacturing cost increases due to high proportion of magnets
Solution Approach 1:
The rotor is divided into multiple segments with recesses created at specific positions. These recesses segment the rotor structure to allow strategic placement of permanent magnets, reducing the total magnet quantity while maintaining efficient magnetic field generation through harmonic component utilization
Solution Approach 2:
The invention changes the operational parameters by utilizing higher harmonic components (3rd, 5th, 7th orders) of magnetomotive force for torque generation instead of only fundamental wave. This parameter change allows fewer permanent magnets to achieve the same or better efficiency, resolving the contradiction between efficiency optimization and manufacturing cost
2Ease of manufacture
If number of magnetic pole pairs is reduced to lower manufacturing cost, then magnet quantity decreases, but electromagnetic pole pairs generation capability must be maintained
Solution Approach 1:
The invention enables dynamic operation by allowing the electrical machine to generate multiple electromagnetic pole pairs (6, 8, 10, or 12 pairs) from a fixed number of permanent magnets (2 pairs). The control system dynamically selects which harmonic components to utilize, providing adaptability equivalent to having variable magnet configurations without physically changing the rotor structure
Solution Approach 2:
By changing the operational parameter of which harmonic component is utilized for torque generation, the system achieves variable electromagnetic pole pair generation. The same physical rotor configuration can produce different electromagnetic characteristics through control strategy changes, maintaining versatility while reducing magnet quantity
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 the number and size of permanent magnets required, lowering manufacturing costs while maintaining similar magnetic flux density, thereby improving the efficiency and operational flexibility of the electrical machine.
Implementation Method 1
The stator winding may be connected to power electronics and designed to generate a rotating field. The magnetic field of the rotor interacts with a magnetic field of the stator.
Implementation Method 2
To generate a rotor magnetic field, the rotor may have permanent magnets. Electrical machines may be operated as a motor or as a generator, converting electrical energy into kinetic energy or vice versa.
Data Source
AI summary
An electrical machine (20) having a stator (21) and a rotor (22) mounted rotatable with respect to the stator (21) is provided. The rotor (22) comprises at least one magnetic pole pair that has two magnets (23). Further, the rotor (22) comprises at least two recesses (25) that extend at least partially through the rotor (22), the recesses (25) being arranged at opposite sides of the rotor (22), and the number of magnetic pole pairs of the rotor (22) being different from the number of electromagnetic pole pairs able to be generated during operation of the rotor (22). Further disclosed is a method of operating the electrical machine (20).