An Accurate and Fast Electromagnetic Coil Parameter Identification Method for Active Magnetic Bearing

Electromagnetic coil is the key component generating the electromagnetic force and supporting rotor high speed contactless rotating in active magnetic bearing (AMB). The defect of the magnetic coil taking place during the manufacturing and assembling process will cause open circuit or short circuit fault of the coil after a long term running of the AMB, which will influence the stable and safe operation of the AMB. This paper has proposed an accurate and fast electromagnetic coil parameter identification method for the health condition monitoring and evaluation of the electromagnetic coil. When the rotor is at standstill, test signal is injected into the magnetic coil by the power amplifier and the electromagnetic coil resistance and inductance are calculated out by the applied input direct current voltage and electromagnetic coil current without obtaining the position signal from the position sensor. A recursive forgetting factor least square algorithm is adopted in the real-time electromagnetic coil parameter identification of the AMB under different rotor shaft positions. The correctness of the proposed AMB electromagnetic coil parameter identification method has been verified by simulation experiment.