Based on the analysis of relationship among the power, torque and stator flux-linkage, the efficiency optimization of the interior permanent magnet synchronous motor drive system for urban rail traction based on instantaneous power control is presented during the transiently operating process of accelerating and braking region. The goal of the method is to control reactive power as zero and improve power factor at the same output of active power. Instantaneously input active and reactive power are changed by the control of stator flux amplitude and position angle to improve the system efficien...
