An MTPA Tracking Method for Cost-Effective Mono-Inverter Multi PMSM Electric Drives

Single-inverter multi-motor architectures offer the potential for significant system simplification, leading to a substantial reduction in required components. This results in a more cost-effective, lightweight, and compact structure. While this approach has been widely studied for Induction Motors and, to some extent, for two parallel-connected Permanent Magnet Synchronous Motors (PMSMs), the case of multiple PMSMs remains in its early stages of research. This paper contributes to advancing the study of optimized control strategies for Single-Inverter Multi-PMSM systems by proposing an innovative method for Maximum Torque Per Ampere (MTPA) point tracking suitable for implementation of a low-cost control platform. This method, here named Distributed Real-Time Computation (DRTC), is compared against a Perturb & Observe (P&O) approach in several operating conditions, including scenarios with motor parameter deviations. The optimal trajectories are investigated, and the impact of parameter variations is examined. The performance of the methods is evaluated through extensive numerical simulations and experimental validation. A comparative analysis of the results highlights the advantages and limitations of each method, demonstrating their effectiveness in tracking the optimal operating point under both steady-state and transient conditions, as well as in the presence of motor parameter variations.