Sensorless control of PM synchronous motors based on MRAS method and initial position estimation

This paper presents a scheme of model reference adaptive system (MRAS) method for the sensorless control of PM synchronous motors. The stability of this scheme is guaranteed by the Popov super stability theorem. Two-phase stator currents and DC bus voltage are used to estimate the rotor speed and position and it doesn't need much calculation. The experimental results show that the estimated values are in close agreement with those obtained from an encoder. The method of estimating the initial rotor position of PM synchronous motors is also discussed in this paper.