Grayscale-free topology optimization for electromagnetic design problem of in-vehicle reactor

In this paper, we propose grayscale-free topology optimization for a reactor design problem where the electromagnetic performance needs to be optimized. A reactor is an electric device to boost electric voltage, and is used as a part of a DC-DC converter in electric and hybrid vehicles. When designing reactors, we need to consider many performance indicators such as inductance and fringing loss. In general, high-performance reactor design that satisfies all requirements is not obvious, and topology optimization is promising for such non-trivial design problems. In this paper, we therefore establish a framework for the electromagnetic design of an in-vehicle reactor on the basis of boundary tracking type level-set topology optimization, which realizes grayscale-free topology optimization. Because of its grayscale-free characteristic, the established framework can completely resolve the numerical problems caused by the so-called grayscale elements. We present several numerical examples to demonstrate the usefulness of the established framework, and we discuss the possibilities for the expansion of the established framework to more difficult and valuable design problems.