Schneider Toshiba Inverter Europe Sas

Mohamad Koteich

Thomas Devos

Al Kassem Jebai

Pascal Combes

Examples include a method for determining a static load torque at standstill applied to a salient pole synchronous motor. The method comprises fixing a first non-zero torque-producing current component and controlling motor speed using a speed loop regulation of a first regulated component to reach a first zero motor speed steady state corresponding to the fixed first non-zero current component, the motor being subjected to the specific static load torque. The method further comprises controlling motor speed using a speed loop regulation of a second regulated component to reach a second zero motor speed steady state corresponding to a fixed second non-zero torque-producing current component, the motor being subjected to the specific static load torque, the first non-zero current component and the second non-zero current component corresponding to different values. The load torque is estimated as a function of components of the first and second zero motor speed steady states.

Determinations of static load torque at standstill

Examples include a method for detecting the evolution of the magnetic state of a permanent magnet rotor. The method includes, during a first and a second time interval, applying a respective direct current command signal to the motor to estimate a respective stator resistance value, and applying a respective alternative voltage command signal corresponding to a specific direct axis stator current value to the motor while measuring respective stator phase current values. The method also includes determining respective rotor flux parameters as a function of the measured respective stator phase current values and of the estimated respective stator resistance values. The method further includes comparing the respective rotor flux parameters. The first and second time intervals are separated by a time period which exceeds at least 100 times any one of a first or second interval length.

Comparison of rotor flux parameters

A method for determining a resonance frequency of a mechanical system including an electric motor coupled to a mechanical load. The method includes starting the motor by providing a supply voltage using a motor controller, and 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. The method further includes measuring a mechanical response of the mechanical system, using a measurement system coupled to the motor, and analyzing the measured response, to determine at least one resonance frequency of the mechanical system.

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

Examples include a method for controlling a variable speed drive driving an electric motor. The variable speed drive is connected to an electric power source and comprises a passive DC-link and an inverter stage controlled by a first controller of the variable speed drive. The passive DC-link is connected to the inverter stage. The method comprises running the electric motor to reach a steady-state operating point, measuring a plurality of values of current or voltage of the passive DC-link, and computing, by a second controller, a frequency spectrum of the DC-link based on the plurality of values of current or voltage measured. The method further comprises detecting a specific resonance frequency by comparing amplitudes of the frequency spectrum to a predetermined pattern, and modifying filter parameters of a digital filter of the DC-link or control parameters of a control law of the electric motor based on the specific resonance frequency.

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Vernon, France

Mohamad Koteich