Residual vibration suppression of stator measurement arm in hydro-generators based on active-passive hybrid control

To address the issue of large residual vibration amplitude and slow decay at the end of the stator measurement arm during intermittent rotation for fixed-point measurements in hydro-generators, which significantly affects measurement accuracy and efficiency, this study proposes an active-passive hybrid control method combining a dynamic vibration absorber (DVA) and a smooth input shaper (SIS) to suppress residual vibrations. First, through theoretical derivation, simulation, and experimental validation, the optimal pendulum length (22 mm) of the DVA was determined. Under this configuration, the DVA reduced the residual vibration peak by 17.1% and shortened the decay time by 25.3%. Subsequently, the proposed SIS shaper was compared with traditional zero vibration (ZV), zero vibration and derivative (ZVD), and extra-insensitive (EI) shapers in terms of residual vibration suppression, time delay, and sensitivity. Simulations and experiments demonstrated that the SIS shaper reduced the residual vibration peak by 91.3% and decreased the decay time by 49.5%. Finally, the integration of these two methods formed the SIS-DVA hybrid control technique. Experimental results confirmed that this hybrid approach further enhanced the suppression capability compared to standalone DVA or SIS, achieving a 94.1% reduction in vibration peak and a 50.9% reduction in decay time.