Electromagnetic attraction type magnetic bearing and control method thereof

An electromagnetic attraction type magnetic bearing includes at least a pair of electromagnets arranged to face each other, a float arranged between the electromagnets and held at the middle position thereof, a sensor for detecting the displacement of the float from a balance position, and/or the speed thereof, and a controller for controlling the electromagnets. The controller determines a variable Z proportional to acceleration in the control direction from the displacement and speed of the float, and operates to set the control current of one of the electromagnets to zero and to control only the control current of the other of the electromagnets, depending on the positive and negative values of the variable.