I. Introduction
Electrical machinery and apparatuses have been used in various industries. Increasing efficiency and decreasing loss in electrical machinery and apparatus are inevitable to keep limited resources on the earth. The electrical steel sheets have been used for main parts of electrical machinery and apparatus. Therefore, increasing efficiency and decreasing loss in electrical machinery and apparatus can be realized to improve magnetic properties of electrical steel sheets. To evaluate the magnetic properties of the electrical steel sheets is very important to improve efficiency and the iron loss. It is assumed that vectors of magnetic flux density B and magnetic field strength H are parallel in the standard magnetic measurement; however, they are not parallel in actual electrical steel sheets. We have proposed the 2-D vector magnetic measurement technique which can measure the B-vector and H-vector that are in different directions [1], [2]. In this case, there is a phase difference between the B-vector and H-vector. The iron loss is calculated by the inner product between the B-vector and H-vector as in the following equation: \begin{equation} W=\frac {1}{\rho T}\int \limits _{0}^{T}\bigg ({{\boldsymbol {H}}}\cdot \frac {\partial {\boldsymbol {B}}}{\partial t}\bigg )dt \end{equation} where is the material density and is the time period, respectively. The technique of applying scratches in electrical steel sheets by the high-power laser irradiation to decrease the iron loss has been proposed previously [3]–[7]. In this paper, we tried to decrease the iron loss by controlling the by laser treatment, which is different from the concept of the conventional technique. We controlled the by laser treatment, and developed a new electrical steel sheet developed by vector magnetic characteristic control which can decrease the iron loss. This paper presents the detail of measured results from the electrical steel sheets developed by vector magnetic characteristic control. Furthermore, we applied our proposed technique into a transformer core model to discuss the effectiveness of it.