Multidisciplinary design optimization of a transverse flux machine based on a multi-step loss calculation method

A transverse flux machines is a special type of electrical machine that offers advantages in terms of torque and power density. Due to the complex simulation, design and manufacturing, transverse flux machines are rarely used despite their many possible applications. The three-dimensional magnetic flux guidance results in a complex geometry of the stator core. As the conventional design of axially stacked electrical steel sheets is not feasible for this type of motor, new manufacturing methods are being researched. In addition, few procedures for simulation and design have been available to date. This paper presents an approach that enables the optimization of an additively manufactured stator core with respect to both efficiency and thermal behavior. In order to efficiently simulate the various power losses of the motor, the results of a 3D-FEM simulation as well as empirical models were combined in several steps. As there is a strong interaction between the thermal and electromagnetic domain for this type of motor, both were simulated iteratively coupled. The shape of the stator core was optimized for low and high speeds, taking into account the respective heating, which led to an improvement in efficiency of more than 5 %pt. in both cases.