Position sensorless control of IPMSMs based on a novel flux model suitable for maximum torque control

Abstract

In this paper, a novel position sensorless control method for interior permanent magnet synchronous motors (IPMSMs) that is based on a novel flux model suitable for maximum torque control has been proposed. Maximum torque per ampere (MTPA) control is often utilized for driving IPMSMs with the maximum efficiency. In order to implement this control, generally, the parameters are required to be accurate. However, the inductance varies dramatically because of magnetic saturation, which has been one of the most important problems in recent years. Therefore, the conventional MTPA control method fails to achieve maximum efficiency for IPMSMs because of parameter mismatches. In this paper, first, a novel flux model has been proposed for realizing the position sensorless control of IPMSMs, which is insensitive to L q. In addition, in this paper, it has been shown that the proposed flux model can approximately estimate the maximum torque control (MTC) frame, which as a new coordinate aligned with the current vector for MTPA control. Next, in this paper, a precise estimation method for the MTC frame has been proposed. By this method, highly accurate maximum torque control can be achieved. A decoupling control algorithm based on the proposed model has also been addressed in this paper. Finally, some experimental results demonstrate the feasibility and effectiveness of the proposed method. © 2012 The Institute of Electrical Engineers of Japan.