Abstract: A field of electric drive devices and electric machines, such as electric motors and electric generators for industrial applications and more particularly to a method and an arrangement for controlling vibration of a variable frequency drive controlled electric machine. In the method for controlling vibration of a variable frequency drive controlled electric machine, the resonance frequency/frequencies and the stiffness are determined in a ramp up/ramp down test; amount of damping is determined in an impulse test; a mechanical transfer function is determined in a steady drive test; a vibration control model is determined utilizing said resonance frequency/frequencies, said stiffness, the amount of damping and the mechanical transfer function; and vibration is controlled utilizing the vibration control model.

Abstract: A method of controlling a 3n-phase electrical machine (7) by means of n power converters (3a, 3b) each being controlled by a respective controller, and each power converter (3a, 3b) being configured to power a respective set of three phases of the electrical machine (7), wherein the method for each controller comprises: a) obtaining measured currents (ia,1, ib,1, ic,1, ia,2, ib,2, ic,2) of the set of three phases of the electrical machine (7) controlled by the controller, b) estimating all currents ({circumflex over (?)}dq, 2, {circumflex over (?)}dq, 1) of all the other sets of three phases of the electrical machine (7), which are controlled by the other controllers, c) transforming the measured currents (ia,1, ib,1, ic,1, ia,2, ib,2, ic,2) and all the estimated currents ({circumflex over (?)}dq,2, {circumflex over (?)}dq,1) using vector space decomposition, VSD, to obtain a set of VSD currents, and d) controlling the corresponding power converter based on the VSD currents.

Abstract: A method of performing scalar-based control of a motor connected to a power converter via at least one passive electrical reactance component, wherein the method includes: estimating a motor current at terminals of the motor to thereby obtain an estimated motor current, and controlling the power converter based on the estimated motor current.

Abstract: A method of controlling a 3n-phase electrical machine (7) by means of n power converters (3a, 3b) each being controlled by a respective controller, and each power converter (3a, 3b) being configured to power a respective set of three phases of the electrical machine (7), wherein the method for each controller comprises: a) obtaining measured currents (ia,1, ib,1, ic,1, ia,2, ib,2, ic,2) of the set of three phases of the electrical machine (7) controlled by the controller, b) estimating all currents ({circumflex over (?)}dq, 2, {circumflex over (?)}dq, 1) of all the other sets of three phases of the electrical machine (7), which are controlled by the other controllers, c) transforming the measured currents (ia,1, ib,1, ic,1, ia,2, ib,2, ic,2) and all the estimated currents ({circumflex over (?)}dq,2, {circumflex over (?)}dq,1) using vector space decomposition, VSD, to obtain a set of VSD currents, and d) controlling the corresponding power converter based on the VSD currents.

Abstract: A method of controlling a multi-phase electrical machine by means of a power converter, wherein the method includes: a) controlling the electrical machine by utilizing vector space decomposition, VSD, wherein the controlling involves releasing control of the current of a harmonic while maintaining control of the current of the fundamental, b) measuring phase currents of the electrical machine while the control of the current of the harmonic is released, c) transforming the current measurements using VSD to obtain a current signature of the harmonic, and d) determining whether a fault is present in the electrical machine or the power converter based on a comparison of the current signature with a reference current signature of the harmonic.

Abstract: A method of controlling a multi-phase electrical machine by means of a power converter, wherein the method includes: a) controlling the electrical machine by utilizing vector space decomposition, VSD, wherein the controlling involves releasing control of the current of a harmonic while maintaining control of the current of the fundamental, b) measuring phase currents of the electrical machine while the control of the current of the harmonic is released, c) transforming the current measurements using VSD to obtain a current signature of the harmonic, and d) determining whether a fault is present in the electrical machine or the power converter based on a comparison of the current signature with a reference current signature of the harmonic.

Abstract: A method of performing scalar-based control of a motor connected to a power converter via at least one passive electrical reactance component, wherein the method includes: estimating a motor current at terminals of the motor to thereby obtain an estimated motor current, and controlling the power converter based on the estimated motor current.

Abstract: For identifying the machine type of an alternating current machine, a direct current is first applied to the stator for aligning the d-axis of the rotor and the magnetic field direction of the stator. Secondly, a direct current is applied to the stator at a current angle which causes the rotors of a permanent magnet machine and a synchronous reluctance machine to exert torque in different directions. The torque direction of the rotor is detected and the machine type is identified based on the torque direction information. The machine type is recognized as a permanent magnet machine or a synchronous reluctance machine depending on the torque direction. If no torque is detected, then the machine type is recognized as an induction machine.

Abstract: A control device for controlling an electric machine with ks windings on a stator and kr windings on a rotor, where ks+kr=n and either ks or kr may be zero, includes an input for receiving commands, an output for outputting control commands to a driver, machine modeling means for modeling behavior of the machine, and decision means connected to the input, output, and machine modeling means for determining the driver control commands. The machine modeling means models behavior of the machine through functional mapping suited for correlating sets of values of electrical and mechanical quantities, sets of values of their total or partial derivatives and/or integral functions with one another. The functional mapping includes an algorithm and/or equation based on at least one state function associated with the electromagnetic field inside the machine and/or based on at least one partial derivative of the state function.

Abstract: A control system for an electric three-phase variable speed motor includes an inverter for providing power to the motor and a control arrangement for controlling the inverter. The control arrangement includes a d and q axis currents determining module configured to repeatedly determine d and q axis currents based on detected currents of the motor. An MTPA control block repeatedly generates reference d and q axis currents based on the determined d and q axis currents and a ratio value such that the ratio of the reference d and q axis currents is equal to the ratio value, which is set to unity. A switching signal generation module repeatedly generates switching signals to control the inverter based on the reference d and q axis currents. A fine adjustment module calculates a magnitude of a current or power of the motor and determines an optimum compensation ratio value.

Abstract: A control system for an electric three-phase variable speed motor includes an inverter for providing power to the motor and a control arrangement for controlling the inverter. The control arrangement includes a d and q axis currents determining module configured to repeatedly determine d and q axis currents based on detected currents of the motor. An MTPA control block repeatedly generates reference d and q axis currents based on the determined d and q axis currents and a ratio value such that the ratio of the reference d and q axis currents is equal to the ratio value, which is set to unity. A switching signal generation module repeatedly generates switching signals to control the inverter based on the reference d and q axis currents. A fine adjustment module calculates a magnitude of a current or power of the motor and determines an optimum compensation ratio value.

Abstract: A control device for controlling an electric machine with ks windings on a stator and kr windings on a rotor, where ks+kr=n and either ks or kr may be zero, includes an input for receiving commands, an output for outputting control commands to a driver, machine modeling means for modeling behavior of the machine, and decision means connected to the input, output, and machine modeling means for determining the driver control commands. The machine modeling means models behavior of the machine through functional mapping suited for correlating sets of values of electrical and mechanical quantities, sets of values of their total or partial derivatives and/or integral functions with one another. The functional mapping includes an algorithm and/or equation based on at least one state function associated with the electromagnetic field inside the machine and/or based on at least one partial derivative of the state function.

Abstract: A method for finding an operating point of an electric motor which includes the steps of generating a perturbation signal, combining the perturbation signal with a current magnitude related to a drive system of the motor or combining the perturbation signal with a power magnitude related to the motor, yielding a combined signal, and sending, based on the combined signal, a flux adjustment signal to adjust a flux of the motor. An apparatus for finding an operating point of an electric motor comprising is also presented.

Abstract: For identifying the machine type of an alternating current machine, a direct current is first applied to the stator for aligning the d-axis of the rotor and the magnetic field direction of the stator. Secondly, a direct current is applied to the stator at a current angle which causes the rotors of a permanent magnet machine and a synchronous reluctance machine to exert torque in different directions. The torque direction of the rotor is detected and the machine type is identified based on the torque direction information. The machine type is recognized as a permanent magnet machine or a synchronous reluctance machine depending on the torque direction. If no torque is detected, then the machine type is recognized as an induction machine.

Abstract: A method for finding an operating point of an electric motor which includes the steps of generating a perturbation signal, combining the perturbation signal with a current magnitude related to a drive system of the motor or combining the perturbation signal with a power magnitude related to the motor, yielding a combined signal, and sending, based on the combined signal, a flux adjustment signal to adjust a flux of the motor. An apparatus for finding an operating point of an electric motor comprising is also presented.