Indirect matrix converter fed PMSM-sensorless control using carrier injection

This paper introduces the permanent magnet synchronous motor (PMSM) drive fed by a three-phase 5 kVA indirect matrix converter (IMC). We studied the likelihood of achieving a high performance low cost synchronous motor drive using direct frequency conversion. The control system of the PMSM needs feedback information on the rotor position angle and rotor speed. To minimize costs these quantities are estimated using the simple signal injection scheme, where high frequency carrier voltage is injected into the motor. The estimator algorithm tracks the rotor position angle exploiting the magnetic saliency of the motor. Estimators based on the fundamental frequency model of the motor cannot be used if the full performance is also required in the zero speed region. Since the estimator studied in this paper exploits the magnetic anisotropy of the motor, there is no stability problem in low and zero speed region and the estimator needs no information about motor parameters. The stability of the sensorless control system is verified by measurements. For comparison the experimental tests were also performed with a conventional voltage source inverter (VSI).