A Perturb-and-Observe based MTPA Algorithm for Mono-Inverter Multi PMSM Electric Drives

Single inverter multi motor architectures enable the possibility of a significant system simplification, with a remarkable reduction of required components, resulting in cheaper, lighter, and more compact structure. This solution has been extensively studied for Induction Motors and only for two parallel-connected Permanent Magnet Synchronous Motors (PMSM). The case of multi PMSMs, instead, is in its early stage. This paper contributes to enrich the study of the optimized control problem for Single Inverter Multi PMSM system proposing two methods for the Maximum Torque Per Ampere point tracking, also in presence of motor parameter deviations. The optimum trajectories are studied, and the effect of motor parameter deviations highlighted. Two suitable MTPA tracking methods are selected and their performance evaluated by means of an extensive numerical investigation. The results comparison allowed to highlight pros and cons of the two methods, testifying the feasibility to effectively track the optimum point both during steady-state and transient conditions and during the motor parameter variations.