Novel Active Damping Scheme for Stable and High Performance <i>v/f</i> Controlled Permanent Magnet Synchronous Motor Driven Passenger Elevator System

The commissioning time, comfort, and reliability of permanent magnet synchronous motor (PMSM) driven elevator systems are highly dependent on the appropriate tuning of vector controller parameters. However, such tuning is a cumbersome process in elevator systems due to the finite compliance of the rope/belt connecting the motor to the elevator car. Hence, it is desirable to perform <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v/f</i>-based speed control instead of vector control for elevators. But the existing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v/f</i> schemes for PMSM may render instability into elevator systems as they do not consider the dynamics of load torque. To resolve this issue, a novel active damping scheme is proposed in this article, where a stator frequency modulated in proportion to the perturbations in the accelerating torque of the rotor and speed error is added to the reference frequency. The proposed scheme involves offline tuning of only two control gain parameters to stabilize the system, minimize the vibrations, and achieve reference trajectory tracking. A simple iterative tuning technique is also proposed to tune the controller gain parameters. Further, it is important to point out that a low cost encoder suffices to implement the proposed technique. Simulation and experimental results are presented to validate the performance of the proposed technique.