Synchronous Vibration Suppression for AMB Systems Based on MCCF-PLL and Positive-Negative-Sequence SRF-PI

Abstract

Active magnetic bearings (AMBs) support rotors through controllable electromagnetic forces and are widely used in high-performance rotating machinery. In practical AMB systems, synchronous vibration is a major vibration source, and its suppression requires accurate rotational speed and phase information without an additional speed sensor. However, conventional synchronous-reference-frame (SRF)-based observation and compensation methods are sensitive to amplitude mismatch, phase nonorthogonality, direct current (DC) offsets, and harmonic contamination, while insufficient sequence separation further degrades speed observation and vibration suppression. To address these issues, this paper proposes a sensorless synchronous vibration suppression method based on a multiple-complex coefficient-filter-based phase-locked loop (MCCF-PLL) and positive-negative-sequence SRF-PI control. The MCCF-PLL extracts the fundamental positive-sequence current component for robust speed and phase observation, while the displacement error is decomposed into positive- and negative-sequence components and regulated by corresponding SRF-PI compensators. The compensation angles are designed using sequence-domain dynamic compliance analysis and updated online during variable-speed operation. Simulation results verify the effectiveness of the proposed method under non-ideal signal conditions. Experimental results demonstrate improved speed-observation performance at 3000 r/min, effective vibration suppression at 1800 and 3600 r/min, and the ability to maintain effective suppression during the run-up from 900 to 3900 r/min and the run-down from 3900 to 900 r/min. These results confirm its feasibility for practical AMB systems.