1. A method of estimating a position of a rotor in a motor, the method comprising: obtaining a current regulation quality index based on a current command and a measured current, the current regulation quality index indicating a quality of current regulation, the obtaining the current regulation quality index comprises, obtaining a current margin based on the current command, determining a first difference between the current command and the measured current, and obtaining the current regulation quality index based on a current margin and the first difference; determining an estimated position of the rotor based on the current regulation quality index and position estimation data; and controlling the motor based on the estimated position of the rotor.