Raw data based model and high dynamic control concept for traction drives powered by synchronous reluctance machines

Abstract

Due to simple mechanical design, resulting in low manufacturing costs, combined with high efficiency and power density, the synchronous reluctance machine (SynRM) is continuously establishing itself as an important machine type for inverter-fed electrical drives. Especially in high volume applications, e.g. traction drives, the SynRM could replace induction machines (IM) by means of significant reduction of the production costs without decreasing the performance of the drive system. However, the inverter control algorithm is getting much more complicated, compared to other machine types. The reason is that the machine is strongly non-linear. In order to optimize the control, an accurate and reliable machine model, based on measurement values, is developed. Furthermore, an optimized control scheme for low voltage battery-fed traction drives, based on the measured machine characteristics, is presented. The traction drive requires a wide speed range and speed variability of the electrical machine. Due to the limited voltage of the battery, the control has to be adaptable to the instantaneous operating point, especially for high speed in the field weakening area. Therefore the Direct Self Control (DSC), originally investigated for the operation of induction machines, is used to control the SynRM drive. Additionally, the control must be able to react to high dynamic speed and load changes without losing stability.