Converter-fed electric motor i.e. asynchronous motor, controlling method, involves determining temperature value of short-circuit cage, and determining estimated reactive power by model values determined in rotor flow-guided machine model

摘要

The method involves determining power dissipation applied in a thermal model, which works according to a thermal equivalent circuit diagram for an electric motor i.e. asynchronous motor (ASM). The electric motor is loaded in operating conditions, and a value of a rotor resistance is determined from a reactive power difference for use in a rotor-flow-oriented flow model. A temperature value of a short-circuit cage is determined and fed for supporting the thermal model. An estimated reactive power is determined by model values determined in a rotor flow-guided machine model. An independent claim is also included for a converter-fed electric motor comprising a temperature sensor.