Keiji Kishimoto

Novel sensorless control for pm synchronous motors based on maximum torque control frame

In this paper, a novel position sensorless vector control for IPMSMs is described. First, we define a novel coordinate frame (hereafter called the maximum torque control (MTC) frame), which has one axis aligned with the current vector of the maximum torque-per-ampere (MTPA) control and propose a sensorless control method for directly estimating the MTC frame. Because the parameter Lqmmiddot for estimating the frame is less affected by magnetic saturation than the conventional Lqm, the influence of magnetic saturation on the position estimation can be greatly suppressed. In additional, excellent current vector loci are observed even when Lqmmiddot is approximated by a constant value. This method is robust against changes in inductance caused by magnetic saturation. After defining an extended electromotive force model based on the proposed frame and a parameter Lqmmiddot for an estimation of the frame, we confirm the effectiveness of the proposed method by simulations and experiments.