The invention relates to a method for damping drive train oscillations of a VSM configured wind turbine. The method comprises determining a drive train damping power signal based on speed signal representing a generator speed, determining a power deviation based on a combination of a power reference for a desired power production, the drive train damping power-signal, a grid power supplied by the line side converter to the grid and a damping power, determining a virtual synchronous machine angle based on the power deviation so that the derivative of the virtual synchronous machine rotational speed is indicative of the power deviation, determining a converter reference for controlling the line side converter to generate the desired active power based on the virtual synchronous machine angle and a voltage reference for a voltage amplitude to be generated by the line side converter, and applying the converter reference to the line side converter.

The invention relates to a method for damping drive train oscillations of a VSM configured wind turbine. The method comprises determining a drive train damping power signal based on speed signal representing a generator speed, determining a power deviation based on a combination of a power reference for a desired power production, the drive train damping power-signal, a grid power supplied by the line side converter to the grid and a damping power, determining a virtual synchronous machine angle based on the power deviation so that the derivative of the virtual synchronous machine rotational speed is indicative of the power deviation, determining a converter reference for controlling the line side converter to generate the desired active power based on the virtual synchronous machine angle and a voltage reference for a voltage amplitude to be generated by the line side converter, and applying the converter reference to the line side converter.

A method for controlling a synchronous double stator electric machine. A first stator and a first set of magnetic poles on a common rotor forms a first electric machine. A second stator and a second set of magnetic poles on the rotor forms a second electric machine. The first electric machine and the second electric machine is shifted mechanically by a predetermined angle. An electrical shift is produced to the control of at least the mechanically shifted electric machine with a respective frequency converter in order to at least partly compensate for the mechanical shift in the mechanically shifted electric machine.

A method for controlling a synchronous double stator electric machine. A first stator and a first set of magnetic poles on a common rotor forms a first electric machine. A second stator and a second set of magnetic poles on the rotor forms a second electric machine. The first electric machine and the second electric machine is shifted mechanically by a predetermined angle. An electrical shift is produced to the control of at least the mechanically shifted electric machine with a respective frequency converter in order to at least partly compensate for the mechanical shift in the mechanically shifted electric machine.

The invention relates to a method (400) for calibrating a controller of an electric machine (120). The method comprises the following steps: specifying (410) a first signal (S_1) for generating a sinusoidal phase current for energising a winding of an electric machine (120); superposing (420) the first signal (S_1) with a test signal (S_Test_i) in order to generate a harmonic oscillation with a predetermined excitation amplitude and/or phase position relative to the phase current, which harmonic oscillation superposes the phase current; detecting (430) a response signal (S_Antw_i), resulting from the superposition of the phase current and the harmonic oscillation, by means of a sensor (130); determining (450) a calibrated signal (S_kal) for generating a harmonic oscillation with a predetermined excitation amplitude and a phase position relative to the phase current on the basis of a determined minimum of a response plane (A_Antw); operating (460) the controller (110) of the electric machine (120) on the basis of the determined minimum

The invention relates to a method (400) for calibrating a controller of an electric machine (120). The method comprises the following steps: specifying (410) a first signal (S_1) for generating a sinusoidal phase current for energising a winding of an electric machine (120); superposing (420) the first signal (S_1) with a test signal (S_Test_i) in order to generate a harmonic oscillation with a predetermined excitation amplitude and/or phase position relative to the phase current, which harmonic oscillation superposes the phase current; detecting (430) a response signal (S_Antw_i), resulting from the superposition of the phase current and the harmonic oscillation, by means of a sensor (130); determining (450) a calibrated signal (S_kal) for generating a harmonic oscillation with a predetermined excitation amplitude and a phase position relative to the phase current on the basis of a determined minimum of a response plane (A_Antw); operating (460) the controller (110) of the electric machine (120) on the basis of the determined minimum

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.

Disclosed herein is a drain pump driving apparatus and a laundry treatment machine including the same. The drain pump driving apparatus and the laundry treatment machine including the same according to an embodiment of the present invention include a motor to operate the drain pump, an inverter to convert a direct current (DC) power to an alternating current (AC) power by a switching operation and output the converted AC power to the motor, an output current detector to detect an output current flowing to the motor, and a controller to control the inverter, wherein the controller may calculate a speed ripple of the motor based on the output current and performs a control operation based on the calculated speed ripple of the motor to change a speed of the motor.

Disclosed herein is a drain pump driving apparatus and a laundry treatment machine including the same. The drain pump driving apparatus and the laundry treatment machine including the same according to an embodiment of the present invention include a motor to operate the drain pump, an inverter to convert a direct current (DC) power to an alternating current (AC) power by a switching operation and output the converted AC power to the motor, an output current detector to detect an output current flowing to the motor, and a controller to control the inverter, wherein the controller may calculate a speed ripple of the motor based on the output current and performs a control operation based on the calculated speed ripple of the motor to change a speed of the motor.

A motor drive device includes: a position command generator which generates a position command; a damping filter unit which includes one or more stages of damping filters which reduce vibration of a device including a load and a motor, applies, to a position command, a damping filter determined based on a model parameter corresponding to a model of the device, and outputs a filtered position command to which the damping filter has been applied; a servo controller which gives a torque command to the motor based on the filtered position command; a low-pass filter unit; a parameter estimation unit which estimates the model parameter from the rotational speed and the torque command of the motor which have passed through the low-pass filter unit; and a vibration determination unit which determines presence or absence of vibration in the model.