A novel position sensor elimination technique for the interior permanent-magnet synchronous motor drive

An approach to the position sensor elimination of an interior permanent-magnet (IPM) synchronous motor drive is proposed. Analytical equations are developed for the calculation of the phase inductance of an IPM motor driven by a current controlled pulse-width modulation (PWM) converter with a hysteresis controller. The calculated phase inductance is then used to estimate the position of the rotor using a set of stored data relating the phase inductance and the rotor position. In order to obtain an unambiguous relation between the phase inductance and the rotor position, the phase inductance of the three phases is calculated during different segments of each electrical cycle. A direct approach to inductance calculation is also proposed which is computationally less intensive and gives uniformly good results. Simulation results are presented and it is shown that the position error is very small for speed control applications. A current regulator using constant frequency switching is also analyzed.<>