Improved synergetic controllers using bounded macro-variables associated with induction motor rotor flux-oriented control

Source abstract

Induction motor drives frequently exhibit transient phenomena, such as stator current and electromagnetic torque overshoots, particularly during speed reversals or abrupt load torque changes. These peaks can induce significant electrical, thermal, and mechanical stress on the system. Most conventional control methods address these issues by imposing external current and torque limits. This paper proposes a synergetic control approach based on a field-oriented rotor control that reduces transients without requiring such constraints. The method uses macro-variables formed by hyperbolic tangent functions, which keep the system trajectories within a smooth, bounded manifold. Integral-based macro-variables are also introduced to improve trajectory tracking and minimize steady-state error. In addition, the synergetic control system for the induction motor is improved to include rotor flux and speed estimation. Simulation results confirm that the proposed strategy can significantly reduce transient peaks and maintain precise and robust control performance under a variety of operating conditions.