METHOD FOR OPERATING ELECTRIC MOTOR

摘要

PROBLEM TO BE SOLVED: To provide a method for protecting magnet elements of an electric motor from temperature-dependent demagnetization during operation.SOLUTION: The present invention is a method for operating an electric motor (9) which is used as an electric servo drive (8) in a power steering system (1). The electric motor (9) is utilized via a plurality of magnet elements and phase windings and controlled by an electronic control unit (11). A temperature(&thetas;) of at least one magnet element (9a) in the plurality of magnet elements of the electric motor (9) is continuously determined during the operation of the electric motor (9) by a temperature model (13). Based on the temperature (&thetas;) of the at least one magnet element (9a) of the electric motor (9) determined by the temperature model (13), an electrical current (I) flowing in at least one of the phase windings of the electric motor (9) is limited, taking into account a predeterminable limit temperature (&thetas;) of the at least one magnet element (9a) of the electric motor (9).