Methods, systems and devices for determining a resonance frequency of a mechanical system

A device for determining a resonance frequency of a mechanical system comprising an electric motor coupled to a mechanical load, said device comprising a control system configured to:

• start the motor by providing a supply voltage using a motor controller;
• once the electric motor is running at a predefined target rotational speed, applying a first excitation signal comprising a voltage pulse superimposed to the supply voltage;
• measure a mechanical response of the mechanical system by measuring stator currents of the motor using a measurement system coupled to the motor, said measurement system comprising one or more current sensors coupled to input terminals of the stator of the motor;
• and
• analyze the measured response, to determine at least one resonance frequency of the mechanical system based on the measured stator currents,
• wherein determining the resonance frequency of the mechanical system comprises:
• calculating, from the measured stator currents, corresponding stator current values expressed in a synchronous frame of the motor;
• calculating phase difference values between the calculated corresponding stator current values;
• identifying oscillations in the calculated phase difference values;
• and
• determining the resonance frequency based on the identified oscillations.