Performance improvements of IPMSM position sensorless control for low-speed operation using ε1-modification approach

This paper proposes a robust-adaptive scheme for position sensorless control of interior permanent magnet synchronous motors (IPMSMs), which can improve robust stability in low-speed operation. It has been pointed out that the performance of position sensorless control system extremely degrades in very low-speed region including standstill, since the back-emf voltage of the motor would be very low, and disturbances such as voltage control error and parameter mismatches significantly influence to stability of position sensorless control. This paper proposes an adaptive full-order observer with epsiv₁-modification approach for robustness improvement of position sensorless control. Finally, the feasibility and effectiveness of the proposed design are shown by experimental results of low-speed operation.