| 研究開始時の研究の概要 |
Nowadays, the demand and production of electrical vehicles (EV) surge due to their positive influence on the environment. Electrical steel sheet (ESS) is adopted in the motor core of the EV. However, mechanical deformation is inevitably introduced into ESS during manufacturing, leading to increased iron loss, and deterioration of magnetic properties. This will cause the low efficiency of the motor core.
This research will focus on the evaluation of the electromagnetic properties of electrical steel sheets to propose a technique for monitoring the efficient performance of the material.
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| 研究実績の概要 |
1. Magnetic Behavior Analysis and Quality Testing: This study explores magnetic behaviors related to hysteresis loss in low-frequency ranges under stress-free conditions. Utilizing a low-frequency magnetic field isolates frequency-dependent iron loss, focusing on hysteresis loss evaluation. The reliability of hysteresis loss calculations was validated, proposing a methodology combining Magnetic Incremental Permeability (MIP) and BH curves. A dynamic-to-quasi-static transition threshold of 20 mHz was identified.
2. Elastic Stress Dependency of Magnetic Behaviors:This study investigates the elastic stress dependency of magnetic behaviors, focusing on micro-magnetic structures. Measurements using techniques like hysteresis curve analysis, Magnetic Barkhausen Noise (MBN), and MIP signals were conducted. Specific indicators plotted against elastic stress establish correlations, revealing changes in domain walls and pinning site strength.
3. Evaluation of Plastic Strain Effects:This study evaluates indicators sensitive to plastic strains across five electrical steel specimens. Comparative analysis identifies indicators with linear relationships with plastic strain or its square root. Notably, some indicators exhibit potential to predict plastic strian.
4. Reproducibility of Indicator Analysis:This research examines reproducibility of indicators sensitive to both elastic stress and plastic strain across different grades of electrical steel. Common indicators, particularly MIP and MBN, show significant linear correlations with both elastic stress and plastic strain.
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