The development of high-efficiency motor drives for various applications is important in the industry 4.0 era, especially for their extensive application to electric vehicles (EVs). In this study, a position sensorless EV synchronous reluctance motor (SynRM) drive has been developed, which exhibits good driving performance and efficiency over a wide speed and load range. To solve the key problems popularly encountered in the existing approaches, the high-frequency injection (HFI) scheme based on q-axis injection has been proposed. In addition, the changed-frequency injection has been adopted considering the effects of speed/load dependent slotting ripple current. Robust observed speed and position controllers have been added to enhance the sensorless control performance. For the SynRM basic driving control scheme, robust current control and adaptive commutation with minimized motor losses have been achieved that yield satisfactory driving performance up to the rated speed and load. Good EV driving performance has been demonstrated experimentally, including starting, dynamic, acceleration/deceleration, and reversible operations. In addition, the steady-state characteristics have been assessed, and the high efficiencies have been observed to be comparable to the standard drive.
Design of Outer-Rotor Permanent-Magnet-Assisted Synchronous Reluctance Motor for Electric Vehicles
