Pseudo-sensorless control of PMSM with linear hall-effect sensor

For the control of electric motors, conventional inverters have utilized position and current sensors, but they undesirable in terms of cost and maintenance effort. For this reason, approaches without the sensors are developed by applying back electromotive force or signal injection-based method which also has some problems related to the the deterioration of control performance in low speed range or cross-saturation and secondary saliency, respectively. To overcome the above-mentioned problems, this study proposes a pseudo-sensorless driver with linear hall sensors that conduct the function of position sensor by measuring the edge-field of permanent magnets. The harmonic components of measured signals are eliminated by adaptive notch filter and phase-locked loop for obtaining accurate rotor position, and then the signals are again synchronized with the fundamental wave of current in stationary reference frame which is used for vector control. The outstanding features of proposed method are simplicity and proper controllability in wide speed range at minimal cost.