Self-commissioning of a bearingless-motor drive

A method and apparatus for self-commissioning a bearingless-motor drive, which includes a bearingless motor and a control unit of the bearingless motor are disclosed. The motor includes at least one winding and at least one permanent magnet. The method includes generating a magnetic model, the magnetic model including a plurality of constant parameters; supplying, while the movable part remains standstill, to the at least one winding at least two unequal currents; measuring, with a magnetic sensor, flux linkages caused by said at least two unequal currents, respectively; calculating, with the magnetic model, flux linkages by inputting to the magnetic model current values equal to the currents supplied to the at least one winding; and fitting, with a least-squares fitting algorithm, at least one constant parameter in the magnetic model such that the difference between the measured and calculated flux linkages will be minimized.