This paper deals with a novel approach for the real-time tracking of the maximum-torque-per-ampere (MTPA) trajectory of an interior permanent-magnet (IPM) motor drive. The proposed approach is based on the injection of proper test signals and allows the MTPA trajectory to be learned and updated in the drive during steady-state conditions. The analytical development of the estimation algorithm, which is supported by a complete validation by simulation, is given in this paper. Finally, experimental results are presented based on a prototype IPM drive system

The paper deals with a novel approach for the real-time tracking of the Maximum-Torque-Per-Ampere (MTPA) trajectory of an IPM motor drive. The proposed approach is based on the injection of proper tests signals and allows the MTPA trajectory to be learned and updated in the drive during steady-state conditions. The analytical development of the estimation algorithm, supported by a complete validation by simulation, is given in the paper. Finally experimental results are presented based on a prototype IPM drive system.

The real-time tracking of the Maximum-Torque-Per-Ampere (MTPA) trajectory in Interior-Permanent-Magnet (IPM) motors is addressed in this paper. The considered approach is based on the injection of proper current test signals and aims at minimizing torque oscillations at the injected frequency, this last condition assuring MTPA operations. Differently from previous approaches motor active power is monitored to detect the out-of-MTPA condition (i.e. torque oscillations), instead of measured motor speed, thus avoiding the use of high-resolution speed transducers, as required by previous approaches. Analytical development are provided, as well as simulation and experimental results, proving the effectiveness of the proposal.