Flatness-Based Trajectory Planning/Replanning for a Permanent Magnet Synchronous Machine Control

Permanent magnet synchronous motors (PMSMs) have been widely used in the aerospace, industrial control, and electric vehicles (EV) industries. A flatness-based control is proposed as an alternative approach to conventional field-oriented control (FOC) for PMSM drive applications due to its suitable dynamic performance and independence from the system operating point. Recently, different types of observers have been employed in flatness-control studies or the control method has been extended to saturated motors to improve its performance. In this paper, a trajectory planning approach for flatness-based control of PMSM drives is presented in order to deal with controller limits, which have received limited attention so far. The trajectory planning affects the response of indirectly controlled states. The proposed method ensures that the maximum allowable motor current is determined by the motor and driver's electrical ratings, as well as the switching voltages, which are limited by the DC-bus voltage (and sometimes, the state of charge of the DC battery), remain within limits to ensure control stability.