Optimal Design of Dy-Free Permanent Magnet Motor for Irreversible Demagnetization through Experimental Design

Recently, with global attention focused on environmental issues, major automakers have stopped producing cars with internal combustion engines. In contrast, production of electric vehicles has been gradually expanding. High-efficiency, high-power permanent magnet motors are essential for electric vehicles. These magnets are generally composed of rare earth materials, which raise concerns about future instability due to continuous price increases and supply challenges caused by national monopolies. In this paper, we propose a permanent magnet motor that does not use one of the rare earths, dysprosium (Dy). However, using permanent magnets without Dy lowers coercivity and lowers temperature characteristics, making them vulnerable to irreversible demagnetization. To address this issue, we modified the permanent magnet structure from bar-type to V-type, which is very vulnerable to external demagnetization factors. We then performed the optimization design using the Taguchi method, an experimental planning technique.