Abstract: A synchronous machine includes a stator with stator windings connected with stator terminals to an electrical grid and a rotor with rotor windings rotatable mounted in the stator, wherein a voltage regulator of the synchronous machine is adapted for outputting an excitation signal to adjust a current in the rotor windings for controlling the synchronous machine. A method for determining control parameters for the voltage regulator includes (i) receiving a first time series of values of the excitation signal and a second time series of measurement values of the terminal voltage in the stator terminals, (ii) determining coefficients of a system transfer function of the synchronous machine, and (iii) determining the control parameters for the voltage regulator from the coefficients of the system transfer function.

Abstract: A synchronous machine includes a stator with stator windings connected with stator terminals to an electrical grid and a rotor with rotor windings rotatable mounted in the stator, wherein a voltage regulator of the synchronous machine is adapted for outputting an excitation signal to adjust a current in the rotor windings for controlling the synchronous machine. A method for determining control parameters for the voltage regulator includes (i) receiving a first time series of values of the excitation signal and a second time series of measurement values of the terminal voltage in the stator terminals, (ii) determining coefficients of a system transfer function of the synchronous machine, and (iii) determining the control parameters for the voltage regulator from the coefficients of the system transfer function.

Abstract: A drive system includes at least one electrical machine and a plurality of rotating components, which are interconnected via shafts. A method for damping torsional oscillations in the drive system includes: determining angular speeds for at least one of the shafts based on measurements in the drive system; determining a damping torque from the angular speeds with a function that models at least some of the electrical machine, the rotating components and the shafts; adapting a reference torque for the at least one electrical machine by adding the damping torque; and controlling the at least one electrical machine with the adapted reference torques.

Abstract: A method for islanding detection in an electrical power grid supplied by an electrical power source. The method includes measuring an output voltage (Vpcc) and a grid current (Ig) at an interconnection point of the power source with the power grid; estimating at least one grid parameter from the output voltage (Vpcc) and the grid current (Ig) based on optimizing a cost function, which minimizes a difference between the measured output voltage (Vpcc) and an estimated output voltage or a difference between the measured grid current (Ig) and an estimated grid current, which estimated output voltage or estimated output current is a function of the measured grid current (Ig) or the measured output voltage (Vpcc) and the least one estimated grid parameter; and detecting an islanding condition by detecting a jump and/or a deviation in the at least one estimated grid parameter.

Abstract: The application relates to a power generation system, including a synchronous generator for converting mechanical power into electrical power at an output side configured for connecting an AC power grid, a first rectifier and a second rectifier each having an AC side connected to the output side of the generator and a DC side, an exciter configured for exciting the, and a selector device having an input side and an output side, the input side connected to the DC side of the first rectifier and to the DC side of the second rectifier and the output side connected to the exciter, the selector device is configured for switching the DC sides in series or in parallel or for transmitting DC power from the first rectifier and the second rectifier corresponding to an arbitrary split ratio to the output side.

Abstract: A drive system includes at least one electrical machine and a plurality of rotating components, which are interconnected via shafts. A method for damping torsional oscillations in the drive system includes: determining angular speeds for at least one of the shafts based on measurements in the drive system; determining a damping torque from the angular speeds with a function that models at least some of the electrical machine, the rotating components and the shafts; adapting a reference torque for the at least one electrical machine by adding the damping torque; and controlling the at least one electrical machine with the adapted reference torques.

Abstract: The invention relates to a power generation system, comprising a synchronous generator (3) for converting mechanical power into electrical power at an output side configured for connecting an AC power grid (1), a first rectifier (12) and a second rectifier (13) each having an AC side (14) connected to the output side of the generator (3) and a DC side (15), an exciter (9) configured for exciting the, and a selector device (18) having an input side (17) and an output side (19), the input side (17) connected to the DC side (15) of the first rectifier (12) and to the DC side (15) of the second rectifier (13) and the output side (19) connected to the exciter (9), whereby the selector device (18) is configured for switching the DC sides (15) in series or in parallel or for transmitting DC power from the first rectifier (12) and the second rectifier (13) corresponding to an arbitrary split ratio to the output side (19).

Abstract: A method for controlling a three-phase electrical converter comprises: selecting a three-phase optimized pulse pattern from a table of pre-computed optimized pulse patterns based on a reference flux; determining a two-component optimal flux from the optimized pulse pattern and determine a one-component optimal third variable; determining a two-component flux error from a difference of the optimal flux and an estimated flux estimated based on measurements in the electrical converter; determining a one-component third variable error from a difference of the optimal third variable and an estimated third variable; modifying the optimized pulse pattern by time-shifting switching instants of the optimized pulse pattern such that a cost function depending on the time-shifts is minimized, wherein the cost function comprises a flux error term and a third variable error term, wherein the flux error term is based on a difference of the flux error and a flux correction function providing a flux correction based on the ti

Abstract: A method for estimating a fundamental component of an AC voltage includes receiving a timely varying measurement signal of the AC voltage; parametrizing a fundamental component of the AC voltage; and determining parameters of the fundamental component based on minimizing a cost function. The fundamental component has a rated frequency, a variable amplitude and a variable phase shift. The cost function is based on an integral of a norm of a difference between the measurement signal and the parametrized fundamental component via a time horizon. The time horizon starts at an actual time point and goes back via a predefined length. The cost function includes a term based on a norm of the difference between a value of the fundamental component at the actual time point and a value of a previously estimated fundamental component at the actual time point, where the previously estimated fundamental component has been determined for a previous time point.

Abstract: A method for controlling an electrical converter system, including: determining a reference output (?m*) and an estimated output (?m) of the electrical converter system based on measurements in the electrical converter system; determining an optimized pulse pattern (ui,n) by selecting from a table of precalculated optimized pulse patterns, which is chosen based on the reference output (?m*) and the estimated output (?m), a pulse pattern including a sequence of switching instants (t*) applied to the electrical converter system; determining a resonant oscillation (?s,h) in the electrical converter system, the resonant oscillation(?s,h) is composed of an electrical machine and a LC filter of the electrical converter system; determining a sequence of future states of the electrical converter system by solving a mathematical model of the electrical converter system subject to optimizing a cost function and subject to a constraint that a modified pulse pattern (ui) is applied to the electrical converter system, whi

Abstract: A method for operating an electrical converter including: determining an optimized pulse pattern from a fundamental voltage reference for the electrical converter, wherein the optimized pulse pattern is determined from a first lookup table and includes discrete voltage amplitude values changing at predefined switching instants; determining a harmonic content reference from the fundamental voltage reference based on a second lookup table, wherein the harmonic content reference is a harmonic current reference determined from the frequency spectrum of a current of the electrical converter or the harmonic content reference is a filtered voltage reference determined by applying a first order frequency filter to a voltage, which current or voltage is generated, when the optimized pulse pattern is applied to the electrical converter; determining a harmonic content error from the harmonic content reference by subtracting an estimated output voltage and/or estimated output current of the electrical converter from the

Abstract: A method for islanding detection in an electrical power grid supplied by an electrical power source. The method includes measuring an output voltage (Vpcc) and a grid current (Ig) at an interconnection point of the power source with the power grid; estimating at least one grid parameter from the output voltage (Vpcc) and the grid current (Ig) based on optimizing a cost function, which minimizes a difference between the measured output voltage (Vpcc) and an estimated output voltage or a difference between the measured grid current (Ig) and an estimated grid current, which estimated output voltage or estimated output current is a function of the measured grid current (Ig) or the measured output voltage (Vpcc) and the least one estimated grid parameter; and detecting an islanding condition by detecting a jump and/or a deviation in the at least one estimated grid parameter.

Abstract: A method for estimating a fundamental component of an AC voltage includes receiving a timely varying measurement signal of the AC voltage; parametrizing a fundamental component of the AC voltage; and determining parameters of the fundamental component based on minimizing a cost function. The fundamental component has a rated frequency, a variable amplitude and a variable phase shift. The cost function is based on an integral of a norm of a difference between the measurement signal and the parametrized fundamental component via a time horizon. The time horizon starts at an actual time point and goes back via a predefined length. The cost function includes a term based on a norm of the difference between a value of the fundamental component at the actual time point and a value of a previously estimated fundamental component at the actual time point, where the previously estimated fundamental component has been determined for a previous time point.

Abstract: The present application is directed to an electrical converter having at least one of an active rectifier and an inverter interconnecting an electrical source with an electrical load. A method for controlling the electrical converter includes receiving at least one estimated control variable, receiving at least one outer loop control variable provided by an outer control loop and determining a control region based on a control error and selecting control parameters based on the control region. The control method then predicts at least one reference control value based on a solution of a physical model of the electrical converter. The solution is based on a constraint that minimizes a difference between the at least one estimated control variable and the at least one outer loop control variable. The control method then determines switching states of the electrical converter based on the reference control value.

Abstract: A method for operating an electrical converter including: determining an optimized pulse pattern from a fundamental voltage reference for the electrical converter, wherein the optimized pulse pattern is determined from a first lookup table and includes discrete voltage amplitude values changing at predefined switching instants; determining a harmonic content reference from the fundamental voltage reference based on a second lookup table, wherein the harmonic content reference is a harmonic current reference determined from the frequency spectrum of a current of the electrical converter or the harmonic content reference is a filtered voltage reference determined by applying a first order frequency filter to a voltage, which current or voltage is generated, when the optimized pulse pattern is applied to the electrical converter; determining a harmonic content error from the harmonic content reference by subtracting an estimated output voltage and/or estimated output current of the electrical converter from the

Abstract: An electrical converter comprises at least one of an active rectifier and an inverter interconnecting an electrical source with an electrical load.

Abstract: A method for controlling an electrical controller system (10), the method comprising, determining a reference output (?*m) and an estimated output (?m) of the electrical converter system (10) based on measurements in the electrical converter system (10); determining an optimized pulse pattern (uin by selecting from a table of precalculated optimized pulse patterns, which is chosen based on the reference output (?*m) and the estimated output (?m), a pulse pattern comprising a sequence of switching instants (ƒ) applied to the electrical converter system (10); determining a resonant oscillation (?0,h) in the electrical converter system (10), whereby the resonant oscillation (?0*) is composed of an electrical machine (16) and a LC fiber (14) of the electrical converter system (10); determining a sequence of future states of the electrical converter system (10) by solving a mathematical model of the electrical converter system (10) subject to optimizing a cost function and subject to a constraint that a modified p

Abstract: An electrical converter is interconnected via a filter with an electrical load or an electrical power source.

Abstract: An electrical converter is interconnected via a filter with an electrical load or an electrical power source.