Rotor Core Steel Orientation for Higher Flux and Lower Iron Loss
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Solution Overview
Problem
Conventional rotor cores for reluctance motors and generators have suboptimal magnetic characteristics, lacking improvements in electrical steel sheets used for these applications.
Innovation Solution
The use of a rotor core composed of electrical steel sheets with specific chemical compositions and orientations, where the sheets have chemical elements like Si, Al, and Ni within certain ranges, and are laminated to optimize magnetic flux density and anisotropy, ensuring the magnetic characteristics are uniform and excellent in the circumferential direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrical steel sheets are used in rotor cores, then manufacturing cost is reduced and ease of manufacture is improved, but magnetic characteristics are suboptimal with insufficient magnetic flux density
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters of the electrical steel sheet, specifically setting C content to 0.0100% or less, Si content to 1.50-4.00%, and total content of Mn, Ni, Co, Pt, Pb, Cu, and Au to 2.50-5.00%. These parameter adjustments optimize magnetic flux density and magnetic characteristics while maintaining manufacturing feasibility through standard steelmaking processes
Solution Approach 2:
The patent employs composite materials by creating a multi-element alloy system that combines traditional electrical steel components (Fe, Si, Al) with additional elements (Mn, Ni, Co, Pt, Pb, Cu, Au) in specific proportions. This composite composition achieves superior magnetic characteristics including enhanced magnetic flux density and controlled anisotropy, resolving the contradiction between performance and manufacturability
2Power
If electrical steel sheets with optimized chemical composition are used, then magnetic flux density is increased, but manufacturing complexity increases due to precise composition control requirements
Solution Approach 1:
The patent achieves high magnetic flux density (B50 in 45° direction greater than 1.7T) by optimizing chemical composition parameters within achievable ranges for conventional steelmaking. The specified composition ranges (C≤0.0100%, Si: 1.50-4.00%, total Mn+Ni+Co+Pt+Pb+Cu+Au: 2.50-5.00%) balance performance requirements with manufacturing capabilities, avoiding overly complex or expensive production processes
Solution Approach 2:
The patent applies local quality by orienting the rolling direction of the electrical steel sheets at specific angles (45° or 135°) relative to the magnetic pole centerlines. This directional orientation exploits the anisotropic magnetic properties of the steel to maximize magnetic flux density in the circumferential direction, achieving local optimization of magnetic performance without requiring uniform complexity throughout the entire rotor core
3Stability of the object's composition
If electrical steel sheets with specific orientation are used, then magnetic characteristics uniformity in circumferential direction is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements local quality by strategically orienting the rolling direction of electrical steel sheets at 45° or 135° angles to the magnetic pole centerlines. This creates anisotropic magnetic properties that are locally optimized for circumferential flux density. The consistent application of this orientation rule across all stator teeth ensures uniform magnetic characteristics around the rotor while maintaining manageable manufacturing precision through standardized positioning procedures
Solution Approach 2:
The patent employs asymmetry by deliberately choosing non-zero angle orientations (45° or 135°) for the rolling direction relative to the magnetic pole centerlines, rather than aligning them parallelly. This asymmetric orientation exploits the crystallographic anisotropy of the electrical steel to enhance magnetic flux density in the circumferential direction, achieving superior magnetic uniformity while the angular relationship provides a clear manufacturing guideline that prevents excessive precision requirements
4Loss of energy
If conventional rotor core designs are used, then device complexity is reduced, but iron loss is high and efficiency is low
Solution Approach 1:
The patent reduces iron loss by changing the chemical composition parameters of the electrical steel sheet, specifically limiting C content to 0.0100% or less to reduce eddy current losses and controlling Si content at 1.50-4.00% to optimize magnetic properties. The addition of specific elements (Mn, Ni, Co, Pt, Pb, Cu, Au) in controlled amounts further refines magnetic characteristics and reduces hysteresis losses, achieving lower overall iron loss without requiring complex device modifications
Solution Approach 2:
The patent applies composite materials by using a multi-element electrical steel alloy that combines Fe with Si, Al, and trace amounts of Mn, Ni, Co, Pt, Pb, Cu, and Au. This composite composition optimizes both magnetic permeability and electrical resistivity, reducing both hysteresis and eddy current losses. The result is decreased iron loss and improved efficiency achieved through material composition rather than increased device complexity
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 magnetic characteristics of rotor cores, leading to improved performance and efficiency in reluctance motors and generators by increasing magnetic flux density and reducing iron loss.
Implementation Method 1
when a B50 in a rolling direction is indicated by B50L, a B50 in a direction at an angle of 90° with respect to the rolling direction is indicated by B50C, and, between B50 in two directions in which a smaller angle of angles with respect to the rolling direction is 45°, a B50 in one direction is indicated by B50D1, a B50 in the other direction is indicated by B50D2
Implementation Method 2
Formula (B) and Formula (C) below are satisfied, and an X-ray random intensity ratio in {100} is 5 or more and less than 30
Implementation Method 3
the electrical steel sheet has a chemical composition containing, by mass %, C: 0.0100% or less, Si: 1.50% to 4.00%, sol. Al: 0.0001% to 1.0%, S: 0.0100% or less, N: 0.0100% or less
Implementation Method 4
Formula (A) below is satisfied, and a remainder includes Fe and impurities
Data Source
AI summary
An electrical steel sheet (300) is formed such that centerlines of four magnetic poles (salient poles) of a rotor core (111) coincide with a direction of easy magnetization (ED1) or (ED2). In addition, the electrical steel sheets (300) are laminated such that the directions of easy magnetization (ED1) and (ED2) are aligned.