Stator-flux-oriented control for traction drives

Traction drives comprise all major challenges to electrical drive systems: High power, large torque, widely varying speed, fast dynamic reaction, compact design, high efficiency and robustness are some of the key aspects. Power-electronic devices feed the selected electric motor - their characteristics influence the design of the control by defining boundaries via maximum voltage, current and switching frequency. Various control strategies are in use and under research, meeting these challenges. These strategies normally use one of two reference systems to perform the calculations needed by the control: Rotor-flux-oriented control (also known as field-oriented or vector control) the rotor-flux-fixed reference system and stator-flux-oriented control the stator-winding-fixed reference system. This paper shortly discusses the major aspects of these two reference systems and then concentrates on state-of-the-art stator-flux-oriented control schemes.