Sensorless operation of surface mount permanent magnet AC (PMAC) motors

a sensorless field oriented control scheme for surface mount permanent magn et ac (PMAC) motor with split phase stator windings is presented. This moto r is obtained by splitting the phase windings of a conventional three phase motor. The six-phase motor, however is run as a three-phase motor by conne cting the split phase stator windings in series, while the taps are made av ailable for voltage measurements. By measuring the terminal voltages and th e line currents, absolute position of the permanent magnet ac motor driven by a current regulated PWM inverter with a hysteresis controller is estimat ed. The estimated position information is independent of the stator resista nce, thus this scheme is even applicable at low speeds. Results are present ed to show the effectiveness of the new controller, and it is also shown th at the position error is negligible.