A complex frequency domain analysis of a closed loop controlled pseudo direct drive

The paper describes a complex frequency domain analysis of a pseudo direct drive permanent magnet machine. The analysis will focus on comparing three different controller structures, in terms of providing damping to the drive system in order to overcome oscillations that appear in the output shaft, caused by the low stiffness of the magnetic gear. Furthermore, based on genetic algorithm tuning of the control gains for the three controllers, closed loop models are established in the complex frequency domain to determine the stability, the damping and the cause of the oscillations. Consequently the best controller structure that improves the dynamic behaviour of the system in term of speed tracking and disturbance rejection could be identified based on the time and frequency domain analysis.