Practical Approximation of Sheet Losses Taking into Account the Guillotine and Laser Cutting Effect

Abstract

Reducing losses in electrical devices is essential for reducing global energy consumption. Losses in the core of electrical machines constitute a significant part of the overall losses—their share increases with the number of machines powered by PWM converters, especially for high-speed machines. Limiting core losses requires precise determination at the design stage of the device. Achieving this goal is possible thanks to numerical or analytical simulation. A necessary input for this process is the correct determination of the properties of the core material. The sheet loss, however, changes due to the machining process, primarily punching. The subject of the work is to develop a sufficiently accurate approximation of electrical steel sheet-specific loss, taking into account the effects of cutting and the width of a given machine element for a wide range of induction and frequency. The method also enables the extrapolation of losses for higher frequencies relevant from the point of view of generating losses in the machine. The developed loss approximation can be used in the finite element simulation and in applying analytical methods. The technique can be successfully used for many grades of non-oriented sheet metal, provided that the requirements specified in the work are met. The proposed approximation allows us to determine the loss of a sample of a certain width in a wide range of magnetic induction magnitude and frequency with an accuracy not worse than 4%.