Non-Intrusive Online Stator Temperature Estimation for Open-End Winding PMSM

This paper proposes a new method for online identification of stator winding temperature for an open-end winding (OEW) permanent magnet synchronous motor (PMSM). The method exploits the zero sequence current (ZSC) due to the third harmonic back electromotive force (EMF) circulating in the system in order to estimate the phase resistance, which, in turn, is used to derive the winding temperature. In order to do this a proposed idea of maximum zero sequence current amplitude along with the actual ZSC amplitude and the electrical speed of the motor is used. The temperature is estimated without any additional sensors in a wide operating speed range. A single synchronous phase-locked loop (PLL) is utilised in order to obtain the required parameters. The independence of the rotor position grants the possibility for the exploitation of the proposed winding temperature estimation method in a variety of control techniques including the sensorless control to increase the robustness of the overall system.