A comparative study on fault detection and correction techniques on active magnetic bearing systems

Abstract

In this paper, the authors distinguish between three real-time fault detection, correction and identification schemes for vibration forces on the rotor of a rotational active magnetic bearing (AMB) system. Historical fault data obtained from a fully suspended 250 kW water cooling AMB pump was used in the design process of the three schemes. The real-time schemes perform three main tasks: 1) fault detection, 2) fault diagnosis and error correction and 3) fault identification. Displacement and current masking were performed during the fault detection stage and the vibratory amplitudes and frequencies were extracted by means of the Wigner-Ville distribution. Pattern recognition techniques, statistical diagnosis and fuzzy logic were used to calculate fault features during the fault diagnosis and error correction stages. During the fault identification stage, data fitting, fuzzy logic and ISO standards were used to calculate the type, parameters, vibratory level and zone of the vibration force. A comparison between the experimental results obtained from a double radial AMB test rack was performed to demonstrate the effectiveness of the proposed schemes in the real-time detection, correction and identification of vibration forces on the rotor of a rotational AMB system. The three real-time schemes were able to correct and minimize vibration forces to a stable working condition.