A self-sensing active magnetic bearing with zero-bias-current control

A zero-bias-current self-sensing active magnetic bearing is proposed. One degree-of-freedom (DOF) of the rotor is controlled by a pair of electromagnets, which are alternatively energized by the proposed circuit. The rotor position of the one DOF is measured by using both electromagnets: the non-energized electromagnet also contributes to the position sensing. The proposed method gives good linearity in the position estimation. The controller of the magnetic levitation consists of a digital signal processor, DSP, which compensates the nonlinearity of the magnetic force and achieves good damping.