Mitigation of Torsional Vibrations in a Modular Drivetrain with Interleaving Control

Abstract

In order to meet requirements in machine design, modularity is often brought forward as a way to cope with load variations and adaptability of the architecture. The considered modular drivetrain consists of several identical induction motors, called motor modules, in cascade on the same shaft. However, implementing a modular drivetrain design evidently has an impact on the performance of the application. New opportunities may arise, such as improved motion dynamics and tolerance to failures. However, on other aspects, e.g., torsional vibrations and synchronization, performance can be negatively influenced. By adding multiple actuators in the drivetrain, additional sources of torque ripple are introduced. The aim of this article is first to investigate the impact of using a modular design on the torsional vibrations in the drivetrain, and second to mitigate these vibrations via an interleaving strategy of the PWM (pulse-width modulation) signals. Simulations and experimental data show that the modular setup requires a proper control strategy in order to ensure that the torsional vibrations in the system remain within the range of a traditional non-modular design. Interleaving of the PWM carrier waveforms in the different motor modules is proposed as a control method to mitigate the torsional vibrations identified in the modular drivetrain. This strategy results in a drivetrain setup that slightly outperforms the benchmark in terms of torsional vibrations.