Interior Permanent Magnet Machine Conic Rotor
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Solution Overview
Problem
The development of high-power interior permanent magnet (IPM) machines for applications like electric and hybrid vehicles has been hindered by the difficulty in finding materials capable of retaining a high-strength magnetic field, until recent advances in material technology enabled the creation of lower-cost high-intensity permanent magnets, allowing for compact, high-power machines with favorable torque-to-size ratios and reduced input voltage.
Innovation Solution
The IPM machine incorporates a rotor with multiple magnetic layers of bonded permanent magnets arranged in conic section shapes, such as parabolic, hyperbolic, or semi-elliptical configurations, which interact with electrical conductors in the stator to enhance magnetic interaction and torque production, and a manufacturing method that places these magnets in rotator cavities to define specific shapes, optimizing magnetic flux and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional permanent magnet materials are used, then high-strength magnetic field can be retained, but material cost is high and availability is limited
Solution Approach 1:
The patent changes the material parameters by using bonded permanent magnets with specific magnetic properties (Br ≥ 1.0 MG, coercivity ≥ 2.0 KOe) instead of traditional high-strength rare earth magnets, achieving adequate magnetic field strength at lower cost through material substitution and parameter optimization
Solution Approach 2:
The patent employs composite magnetic layers combining bonded permanent magnets with magnetic conductive materials, creating a composite structure that maintains magnetic field strength while reducing dependence on expensive rare earth materials through material composition optimization
2Ease of manufacture
If conventional magnetic layer shapes are used, then manufacturing is simpler, but magnetic flux optimization and torque production are reduced
Solution Approach 1:
The patent applies curved surface geometry to the magnetic layers, forming conic section shapes (parabolic, hyperbolic, or elliptical) that optimize magnetic flux distribution and enhance torque production while maintaining manufacturability through mold-based formation processes
Solution Approach 2:
The patent optimizes geometric parameters of the magnetic layers by defining specific conic section shapes with controlled curvature and orientation, improving magnetic flux density and torque characteristics without significantly complicating the manufacturing process
3Power
If high-power density is achieved through compact design, then torque-to-size ratio improves, but magnetic material requirements become more stringent
Solution Approach 1:
The patent transitions from conventional planar or cylindrical magnetic arrangements to three-dimensional conic section shaped magnetic layers, utilizing spatial geometry optimization to enhance magnetic flux density and achieve high power density without requiring extreme magnetic material strength
Solution Approach 2:
The patent uses curved conic section surfaces to concentrate and direct magnetic flux more effectively within the compact rotor volume, achieving high torque-to-size ratios through geometric flux concentration rather than relying solely on high-strength magnetic materials
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 configuration enhances the reluctance torque of the IPM machine, maximizing power output and efficiency while simplifying manufacturing and reducing costs by using bonded magnets, which can be formed into complex shapes with lower eddy current losses.
Implementation Method 1
The magnetic layer has a substantially conic section shape and is configured to magnetically interact with the electrical conductors
Implementation Method 2
The magnetic layer has a substantially conic section shape... This configuration enhances the reluctance torque of the IPM machine
Implementation Method 3
bonded permanent magnets... capable of retaining a high-strength magnetic field
Data Source
AI summary
An interior permanent magnet machine includes a stator including a plurality of electrical conductors. The interior permanent magnet machine further includes a rotor concentrically disposed in relation to the stator. The rotor is configured to rotate relative to the stator about a rotational axis and includes a plurality of polar pieces arranged annularly about the rotational axis. At least one of the polar pieces includes a magnetic layer configured to magnetically interact with the electrical conductors. The magnetic layer has a substantially conic section shape.