Passivity-Based Conditions for Asymptotic Stability of Speed Control for Three-Phase and Dual Three-Phase Permanent Magnet Synchronous Motors

In this paper, we present sufficient conditions for guaranteeing global asymptotic speed regulation for three-phase and dual three-phase permanent magnet synchronous motors. Contrary to standard cascade control design approaches, where the inner and outer controllers cannot be tuned separately, we derive conditions on the controllers gains that are independent of each other. This tuning method is possible thanks to decomposing the machine dynamics as a negative feedback interconnection of two subsystems. The provided conditions then ensure the passivity of each subsystem, which in turn guarantees the asymptotic stability of the closed-loop equilibrium.