Magnetic phase transition

In low-cost permanent magnet synchronous motor (PMSM) drive systems, the rotor position is usually estimated based on the back-electromotive force. However, such estimation methods have the common drawback of having large errors in low-speed regions. In order to solve that drawback in the startup phase, the I-f startup method is studied as its compatibility with the FOC control structure.

8p viyoko 01-10-2024 1 1   Download

Research objectives of the thesis: Clarification influence of the elements Na, Sr and Ba substituting for La/Ca and crystal size on the magnetic properties, phase transition and magnetocaloric effects of La0,7Ca0,3MnO3 materials. Found the materials for significant mmagnetocaloric parameters have potential for applications in magnetic refrigeration.Determine the effect of replacing Sr/Ba for Ca in La0,7Ca0,3MnO3 and Co substituting for Mn in La0,7Sr0,3MnO3 on their critical behavior as well as the ferromagnetic interactions order.

31p extraenglish 24-05-2021 25 4   Download

Influence of substitution of 3d metals for Mn on properties of La0.67Ca0.33Mn0.9 TM0.1O3 (TM = Fe, Co, Ni) compounds was studied. Ferromagnetic – paramagnetic and metals – insulator transitions were significantly affected by Mn-site substitution. However, no observable difference was found in their crystal structure from X-ray diffraction analysis. At room temperature the structure characterization of these compounds gave the single phase and structure is the distortion orthorhombic cell with space group symmetry Pnma.

12p 12120609 01-06-2020 13 2   Download