With the advantages of frictionless, no need of lubrication, no pollution, low consuming and long life, active magnetic bearing (AMB) is applied in the primary helium circulator of the High Temperature Gas-Cooled Reactor-Pebble bed Module (HTR-PM), which is under construction in Shidao Bay Nuclear Power Plant.
Active magnetic bearing is a typical mechatronic system with interconnection of mechanical and electronic components with the function of picking up signals, processing and producing. Displacement sensor is an important component to pick up signals for stability control, and also the most susceptible part to fail due to variation of air temperature and vibration of high rotation speed. However, rotating system can’t run normally if a single sensor fails in AMB without redundancy design. For security considerations, higher reliability is required in some special equipment, especially in primary helium circulator of HTR-PM. Design and implementation of redundant sensors is an effective method.
This paper reviewed the present research of fault diagnosis and redundant control of displacement sensors, simulation of coil’s short-circuit and open-circuit fault was made with MATLAB/SIMULINK. Parameters were optimized for fault diagnostic circuit by Multisim. Based on the high reliability demand, redundancy design was applied both on structure and control system in AMB. Schematic drawing and PCB board were finished by Altium Design, and experiments were carried out. The result showed that if the coils of sensor failed, AMB system could still work normally by switching to the redundant sensors automatically.