Abstract: A grain oriented electrical steel sheet has thickness of forsterite film at bottom portions of grooves formed on a surface of the steel sheet is ?0.3 ?m, groove frequency is ?20%, abundance ratio of grooves crystal grains directly beneath themselves, each crystal grain having orientation deviating from Goss orientation by ?10° and grain size ?5 ?m, total tension exerted on the steel sheet in the rolling direction by the forsterite film and tension coating is ?10.0 MPa, total tension exerted on the steel sheet in a direction perpendicular to the rolling direction by the forsterite film and tension coating is ?5.0 MPa and total tension satisfies 1.0?A/B?5.0, where A is total tension exerted in rolling direction by forsterite film and tension coating, and B is total tension exerted in direction perpendicular to rolling direction by forsterite film and tension coating.

Abstract: A grain oriented electrical steel sheet may reduce iron loss of material with linear grooves formed thereon for magnetic domain refinement and offer excellent low iron loss properties when assembled as an actual transformer, where the steel sheet has sheet thickness of 0.30 mm or less, linear grooves are formed at intervals of 2-10 mm in the rolling direction, the depth of each of the linear grooves is 10 ?m or more, the thickness of the forsterite film at bottom portions of the linear grooves is 0.3 ?m or more, total tension applied to the steel sheet by the forsterite film and tension coating is 10.0 MPa or higher in rolling direction, and the proportion of eddy current loss in iron loss W17/50 of the steel sheet is 65% or less when alternating magnetic field of 1.7 T and 50 Hz is applied to the steel sheet in the rolling direction.

Abstract: A grain-oriented electrical steel sheet subjected to magnetic domain refining by linearly introducing strains in a direction intersecting a rolling direction of the steel sheet repeatedly with intervals in the rolling direction, wherein if a repeating interval of the strains in the rolling direction is d (mm) and, when the steel sheet is placed on a flat surface, a mean value of difference between a height from the flat surface in linear strain-introduced areas of a steel sheet surface and a height from the flat surface in intermediate points between adjacent linear strain-introduced areas is h (mm), then the ratio h/d of the h to the d is 0.0025 or more and 0.015 or less.

Abstract: A motor control apparatus includes: duty calculation units that calculate a duty of a PWM signal based on a deviation between a value of a physical quantity of a motor with a command value; and a duty setting unit that performs setting of the duty based on the duty calculated by the duty calculation units. The duty setting unit maintains a present duty until new duty is input from any one of the plurality of duty calculation units, and updates the duty from the present duty to the new duty when the new duty is input from any one of the plurality of duty calculation units. A PWM signal generation unit generates the PWM signal based on the duty set by the duty setting unit and a carrier signal generated by a carrier signal generation unit.

Abstract: The present invention provides a grain-oriented electrical steel sheet with reduced iron loss over a wide range of sheet thickness by providing a grain-oriented electrical steel sheet with an actually measured sheet thickness t (mm) that includes a closure domain region extending linearly in a direction from 60° to 120° with respect to the rolling direction on a surface of the steel sheet, the closure domain region being formed periodically at a spacing s (mm) in the rolling direction, such that h?74.9t+39.1 (0.26?t), h?897t?174.7 (t>0.26), (w×h)/(s×1000)??12.6t+7.9 (t>0.22), and (w×h)/(s×1000)??40.6t+14.1 (t?0.22), where h (?m) is the depth and w (?m) is the width of the closure domain region.

Abstract: A grain-oriented electrical steel sheet exhibits reduced iron loss and reduced noise. The electrical steel sheet has magnetic domains refined by regions with a high lattice defect density being locally formed on the surface of or within the steel sheet, in which the regions with a high lattice defect density has a hardness, as measured by a micro Vickers hardness meter, equal to or lower than that of other regions.

Abstract: A grain-oriented electrical steel sheet, on which magnetic domain refining treatment by strain application has been performed, has an insulating coating with excellent insulation properties and corrosion resistance. The grain-oriented electrical steel sheet is obtained by irradiating a steel sheet with a high-energy beam to apply, to the steel sheet, linear strain extending in a direction that intersects a rolling direction of the steel sheet, and then re-forming an insulating coating on the steel sheet, in which in an irradiation mark region due to the high-energy beam, a ratio of an area containing defects on the insulating coating is 40% or less, a maximum width of the irradiation mark region in the rolling direction is 250 ?m or less, and a thickness of the insulating coating is 0.3 ?m or more and 2.0 ?m or less.

Abstract: A grain-oriented electrical steel sheet has low iron loss properties obtained though magnetic domain refining treatment by a chemical means. The steel sheet has a linear groove extending in a direction forming an angle of 45° or less with a direction orthogonal to a rolling direction of the steel sheet, in which presence frequency of fine grains with a length in the rolling direction of 1 mm or less in a floor portion of the groove is 10% or less, including 0% indicative of the absence of fine grains, the groove is provided with a forsterite film in an amount of 0.6 g/m2 or more in terms of Mg coating amount per one surface of the steel sheet, and an average of angles (3 angles) formed by <100> axes of secondary recrystallized grains facing the rolling direction and a rolling plane of the steel sheet is 3° or less.

Abstract: A motor control apparatus includes: duty calculation units that calculate a duty of a PWM signal based on a deviation between a value of a physical quantity of a motor with a command value; and a duty setting unit that performs setting of the duty based on the duty calculated by the duty calculation units. The duty setting unit maintains a present duty until new duty is input from any one of the plurality of duty calculation units, and updates the duty from the present duty to the new duty when the new duty is input from any one of the plurality of duty calculation units. A PWM signal generation unit generates the PWM signal based on the duty set by the duty setting unit and a carrier signal generated by a carrier signal generation unit.

Abstract: Provided is a grain-oriented electrical steel sheet, with reduced iron loss by magnetic domain refining treatment, exhibiting an excellent noise property and effectively reducing noise generated when stacked in an iron core of a transformer. In a grain-oriented electrical steel sheet including a forsterite film and a tension coating on both surfaces, magnetic domain refining treatment has been performed to apply linear thermal strain to the grain-oriented electrical steel sheet, the magnitude of deflection in the rolling direction of the steel sheet is 600 mm or more and 6000 mm or less as the curvature radius of the deflected surface with the surface having the strain applied thereto being the inner side, and the magnitude of deflection in the direction orthogonal to the rolling direction is 2000 mm or more as the curvature radius of the deflected surface with the surface having the strain applied thereto being the inner side.

Abstract: A grain-oriented electrical steel sheet, on which magnetic domain refining treatment by strain application has been performed, has an insulating coating with excellent insulation properties and corrosion resistance. In a grain-oriented electrical steel sheet, linear strain having been applied thereto by irradiation with a high-energy beam, the linear strain extending in a direction that intersects a rolling direction of the steel sheet, an area ratio of irradiation marks within an irradiation region of the high-energy beam is 2% or more and 20% or less, an area ratio of protrusions with a diameter of 1.5 ?m or more within a surrounding portion of the irradiation mark is 60% or less, and an area ratio of exposed portions of steel substrate in the irradiation mark is 90% or less.

Abstract: The present invention proposes a method that can reduce the noise generated by a transformer core and the like when formed by laminations of a grain-oriented electrical steel sheet in which core loss has been reduced by a magnetic domain refinement process. In this steel sheet, linear distortion extending with an orientation in which an angle formed with a direction perpendicular to the rolling direction of the steel sheet is an angle of 30° or less is periodic in the direction of rolling of the steel sheet, core loss (W17/50) is 0.720 W/kg or less, and magnetic flux density (B8) is 1.930 T. The volume of the closure domain arising in the distortion part is 1.00-3.00% of the total magnetic domain volume within the steel sheet.

Abstract: A grain-oriented electrical steel sheet to which electron beam irradiation is applied, has a film and a thickness of t (mm), wherein no rust is produced on a surface of the steel sheet after a humidity cabinet test lasting 48 hours at a temperature of 50° C. in an atmosphere of 98% humidity, and iron loss W17/50 after the electron beam irradiation is reduced by at least (?500 t2+200 t?6.5) % of the iron loss W17/50 before the electron beam irradiation and is (5 t2?2 t+1.065) W/kg or less.

Abstract: A grain oriented electrical steel sheet has linear grooves for magnetic domain refinement formed on a surface thereof and may reduce iron loss by using these linear grooves, where the proportion of those linear grooves having crystal grains directly beneath themselves, each crystal grain having an orientation deviating from the Goss orientation by 10° or more and a grain size of 5 ?m or more, is controlled to 20% or less, and secondary recrystallized grains are controlled to have an average ? angle of 2.0° or less, and each secondary recrystallized grain having a grain size of 10 mm or more is controlled to have an average ?-angle variation of 1° to 4°.

Abstract: A grain oriented electrical steel sheet has grooves on one surface of the steel sheet formed for magnetic domain refining, the steel sheet including a forsterite film and a tension coating on front and back surfaces of the steel sheet, wherein the tension coating is applied on a surface with the grooves in a coating amount A (g/m2) and is applied on a surface with no grooves in a coating amount B (g/m2), the coating amounts A and B satisfying (1) and (2): 3?A?8??(1); and 1.0<B/A?1.8??(2).

Abstract: A grain oriented electrical steel sheet has thermal strain introduced thereinto in a dotted-line arrangement in which strain-imparted areas are lined in a direction that crosses a rolling direction of the steel sheet, wherein the strain-imparted areas introduced in the dotted-line arrangement have a size from 0.10 mm or more to 0.50 mm or less and an interval between the adjacent strain-imparted areas is from 0.10 mm or more to 0.60 mm or less.

Abstract: A grain oriented electrical steel sheet has linear grooves for magnetic domain refinement formed on a surface thereof and may reduce iron loss by using these linear grooves, where the proportion of those linear grooves having crystal grains directly beneath themselves, each crystal grain having an orientation deviating from the Goss orientation by 10° or more and a grain size of 5 ?m or more, is controlled to 20% or less, and secondary recrystallized grains are controlled to have an average ? angle of 2.0° or less, and each secondary recrystallized grain having a grain size of 10 mm or more is controlled to have an average ?-angle variation of 1° to 4°.

Abstract: A grain oriented electrical steel sheet has grooves on one surface of the steel sheet formed for magnetic domain refining, the steel sheet including a forsterite film and a tension coating on front and back surfaces of the steel sheet, wherein the tension coating is applied on a surface with the grooves in a coating amount A (g/m2) and is applied on a surface with no grooves in a coating amount B (g/m2), the coating amounts A and B satisfying (1) and (2): 3?A?8??(1); and 1.0<B/A?1.8??(2).

Abstract: A grain oriented electrical steel sheet has thickness of forsterite film at bottom portions of grooves formed on a surface of the steel sheet is ?0.3 ?m, groove frequency is ?20%, abundance ratio of grooves crystal grains directly beneath themselves, each crystal grain having orientation deviating from Goss orientation by ?10° and grain size ?5 ?m, total tension exerted on the steel sheet in the rolling direction by the forsterite film and tension coating is ?10.0 MPa, total tension exerted on the steel sheet in a direction perpendicular to the rolling direction by the forsterite film and tension coating is ?5.0 MPa and total tension satisfies 1.0?A/B?5.0, where A is total tension exerted in rolling direction by forsterite film and tension coating, and B is total tension exerted in direction perpendicular to rolling direction by forsterite film and tension coating.

Abstract: A grain oriented electrical steel sheet may reduce iron loss of material with linear grooves formed thereon for magnetic domain refinement and offer excellent low iron loss properties when assembled as an actual transformer, where the steel sheet has sheet thickness of 0.30 mm or less, linear grooves are formed at intervals of 2-10 mm in the rolling direction, the depth of each of the linear grooves is 10 ?m or more, the thickness of the forsterite film at bottom portions of the linear grooves is 0.3 ?m or more, total tension applied to the steel sheet by the forsterite film and tension coating is 10.0 MPa or higher in rolling direction, and the proportion of eddy current loss in iron loss W17/50 of the steel sheet is 65% or less when alternating magnetic field of 1.7 T and 50 Hz is applied to the steel sheet in the rolling direction.