Speaker
Description
Permanent magnet motors use rare earth permanent magnets that are sintered light rare earth elements (Nd, etc.), heavy rare earth elements (Dy, Tb, etc.), and iron. Currently, since heavy rare earth element imports depend entirely on specific countries, high-performance permanent magnets that exclude heavy rare earth elements have been developed in order to stabilize the domestic supply chain. However, although they can be applied to large-sized drive motors such as electric vehicles, they are difficult to apply to small and low-capacity motors such as servo motors. High-performance and high-durability servo motor technology that applies anisotropic bonded magnets that exclude heavy rare earth elements and can be manufactured and applied to medium and small motors such as servo motors is required. Existing motors use magnets that are sintered by mixing light rare earth elements (Nd, etc.) and heavy rare earth elements (Dy, Tb, etc.) and have high magnetic flux density characteristics of approximately 1.2 T or more. In the case of the rare earth-excluded anisotropic bonded magnet, the magnetic flux density is about 20% lower than that of the existing sintered magnet at a maximum of 0.95T, so the size increases when applied to the existing servo motor. It is possible to develop a low-cost motor with the same or higher output density characteristics as the existing motor using the existing sintered magnet through the design technology for high-output servo motors using the rare earth-excluded anisotropic bonded magnet.
In the case of the existing rare earth-based isotropic permanent magnet, a thin film coating is required, and the gap expansion due to the thin film coating thickness is reflected as a phenomenon of reduced output. In the case of the rare earth-reduced anisotropic permanent magnet, the thin film coating can be excluded, so the electromagnetic gap reduction effect can be obtained. In order to verify the application and validity of the rare earth-reduced anisotropic permanent magnet developed through this study, the developed material was applied to servo motors of various capacities, and suitability analysis was conducted through series development.
We plan to confirm and establish the irreversible demagnetization characteristics of the development material according to the environmental temperature through electromagnetic analysis and test evaluation, and through this, we aim to confirm the optimal driving environment of the motor to which the material is applied.
We propose the development process and results of low-cost permanent magnets, and analytically elucidate the design characteristics and input/output characteristics of the motor to which the permanent magnet is applied. In addition, we finally elucidated the validity of the material and the development product through production and test evaluation.
Acknowledgements
This study was supported by the Ministry of Trade, Industry, and Energy (MOTIE) and Korea Evaluation Institute of Industrial Technology (KEIT) of the Republic of Korea under Grant 20023875
