Patent ID: 9148079
Filing Date: 2015-09-29
Classification: B62D,H02P

Abstract:
1. A method for operating an electric motor, which is used as an electric servo drive in an electronic power steering system of a motor vehicle for power assistance, and which has a number of magnetic elements and phase windings, and is actuated and/or controlled by an electronic control unit of the electronic power steering system: wherein a temperature of at least one magnetic element of the electric motor is continuously determined during the operation of the electric motor by way of a temperature model; wherein, based on the temperature of the at least one magnetic element of the electric motor determined by way of the temperature model, an electrical current flowing in at least one of the phase windings of the electric motor is limited, taking into account a predeterminable limit temperature of the at least one magnetic element of the electric motor; wherein the temperature model for determining the temperature of the at least one magnetic element of the electric motor receives, as an input variable, at least one metrologically captured or calculated temperature that is present in a region of the electric servo drive; wherein at least one temperature present in the region of the electric servo drive is a temperature prevailing in at least one of the phase windings of the electric motor; and wherein the temperature prevailing in at least one of the phase windings of the electric motor can be metrologically captured or calculated based on an electrical resistance in the at least one phase winding of the electric motor.