I. Introduction
The reluctance synchronous machine (RSM) is a favourable sustainable and future-oriented electric drive. One advantage is the absence of raw materials (NdFeB magnets). In addition, there are no rotor-side copper losses. The torque generation is based on a reluctance difference between the direct axis (d-axis) and the quadrature axis (q-axis). The ripple strongly depends on the selected rotor design. The torque ripple is the ratio of the maximum torque deviation ∆T to the average torque Taverage at a steady-state operating point. With a faulty chosen and balanced rotor design the torque ripple can increase related to the average torque Taverage up to 100 % [1]. A compromise between mechanical strength and saliency must be made [2]. Due to the high torque ripple, the RSM is often used in applications where these torque pulsations are not critical for the operation. Therefore the electric drive is frequently used in fans or pumps.