Design and analysis of position estimator based on instantaneous power for sensorless drive of permanent magnet synchronous motor

This paper proposes a simple position estimator based on instantaneous power and a tuning procedure for the proposed estimator in driving surface mounted permanent magnet synchronous motor. In the instantaneous power of three phase system, the imaginary and real power has the information related to the position and velocity. Using the instantaneous power, the difference between real rotor position and estimated rotor position is calculated. For easy design, gain parameters are described as bandwidth of position estimator. And, the proper bandwidth is expressed as the desired load transient response, system inertia and permitted acceleration range. Also, the sensitivity of phase resistance and inductance is analyzed. The described mathematical results show the necessity of accurate parameter information. Simulation and experimental results show the validity of the proposed design method and analysis.