Nd-fe-b permanent magnet with cerium, rotor assembly, electromechanical transducer, wind turbine
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Solution Overview
Problem
The high cost and scarcity of Dysprosium (Dy) and Terbium (Tb) in Nd-Fe-B permanent magnets used in electromechanical transducers, particularly in wind turbines, necessitates the development of a cheaper alternative with similar magnetic properties to maintain efficiency and reliability.
Innovation Solution
A Nd-Fe-B permanent magnet composition with reduced Dy and Tb content, incorporating Cerium (Ce) and optimized geometric dimensions, maintains high coercivity and remanence, allowing for reduced material costs while ensuring durability and performance under temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Dysprosium (Dy) and Terbium (Tb) are added to increase intrinsic coercivity, then the demagnetization resistance is improved, but the material cost increases significantly
Solution Approach 1:
The patent changes the chemical composition parameters by reducing Dy and Tb content to below detection limits while increasing Ce content to 5-10 weight%, and optimizes the spatial dimension parameter by setting magnet height between 18-26mm. This parameter optimization maintains sufficient demagnetization resistance (intrinsic coercivity 990-1210 kA/m at 20°C) while significantly reducing material cost.
Solution Approach 2:
The patent creates a composite Nd-Fe-B permanent magnet material system combining Neodymium (20-25 wt%), Iron, Boron, and Cerium (5-10 wt%), replacing the conventional Dy/Tb-containing composition. This composite material achieves cost reduction while maintaining required magnetic performance through optimized phase composition and microstructure.
2Ease of manufacture
If cheaper rare earth materials like Cerium (Ce) are used to replace Nd and Pr, then the material cost is reduced, but the magnetic properties are negatively influenced
Solution Approach 1:
The patent optimizes the Ce content parameter to a specific range (5-10 weight%) and adjusts the corresponding Nd+Pr content (20-25 weight%) and magnet dimensions (height 18-26mm) to compensate for Ce's lower magnetic performance. This parameter optimization ensures sufficient magnetic properties (remanence 1.246-1.584 T, intrinsic coercivity 990-1210 kA/m) are maintained while achieving cost reduction.
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 magnet achieves sufficient demagnetization resistance and magnetic performance, enabling reliable operation of electromechanical transducers and wind turbines over 20 years with reduced material expenses.
Implementation Method 1
The above mentioned magnetic field linkage couples the stator with the rotor
Implementation Method 2
An electric generator is an electromechanical transducer that converts mechanical energy into electrical energy also using magnetic field linkage
Implementation Method 3
the magnet has at a temperature of 20°C: an intrinsic coercivity which is between 990 kA/m and 1210 kA/m
Data Source
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AI summary
It is described a Nd-Fe-B permanent magnet (354) comprising 28-35 weight % of rare earth elements, wherein the content of the sum of Nd (Neodymium) and Pr (Praseodymium) is between 20 and 25 weight %, wherein the content of Ce (Cerium) is between 5 and 10 weight%, wherein the spatial extension, i.e. the height (h) of the magnet (354) in the main magnetization direction of the Nd-Fe-B permanent magnet (354) is between 18mm and 26mm. It is further described a rotor assembly (350) for an electromechanical transducer (340).