Abstract: The disclosure relates to a converter control unit or power system stabilizing unit for counteracting oscillations in electric power systems that is equipped and employed to provide and processes information for system-wide monitoring, protection, control and metering. It comprises means for synchronized (e.g. via GPS or another absolute/global time reference) sampling of voltages and/or currents, means for down-sampling in order to decrease the number of samples, and means for calculating phasors, i.e. time stamped amplitude and phase angle of the voltages and/or currents.

Abstract: A method is disclosed for the operation of a converter circuit, wherein the converter circuit has a converter unit having a multiplicity of actuatable power semiconductor switches and an LCL filter which is connected to each phase connection of the converter unit, in which the actuatable power semiconductor switches are actuated by means of an actuation signal (S) formed from a hysteresis active power value (dP), from a hysteresis reactive power value (dQ) and from a selected flux sector (?n). The hysteresis active power value (dP) is formed from a differential active power value (Pdiff). In addition, the hysteresis reactive power value (dQ) is formed from a differential reactive power value (Qdiff). An apparatus for carrying out the method is also disclosed.

Abstract: A switchgear cell is disclosed having a first energy store and a second energy store connected in series therewith, having a first, second, third and fourth power semiconductor switch, which are connected in series, wherein the first, second, third and fourth power semiconductor switch are in each case one drivable bidirectional power semiconductor switch with a controlled unidirectional current-conducting direction. The first power semiconductor switch is connected to the first energy store, and the fourth power semiconductor switch is connected to the second energy store. A third energy store is connected to the junction between the first and the second power semiconductor switch and the junction between the third and the fourth power semiconductor switch.

Abstract: A method is disclosed for the operation of a converter circuit, wherein the converter circuit has a converter unit having a multiplicity of actuatable power semiconductor switches and an LCL filter which is connected to each phase connection of the converter unit, in which the actuatable power semiconductor switches are actuated by means of an actuation signal (S) formed from a hysteresis active power value (dP), from a hysteresis reactive power value (dQ) and from a selected flux sector (?n). The hysteresis active power value (dP) is formed from a differential active power value (Pdiff). In addition, the hysteresis reactive power value (dQ) is formed from a differential reactive power value (Qdiff). An apparatus for carrying out the method is also disclosed.

Abstract: A converter unit is disclosed which produces an output voltage based on reference signals (u*d, u*q) that are generated from active and reactive components (P, Q) of the converter's output power. A first reference signal for a reactive component of the output voltage (u*q) is set to zero, thus regulating the reactive component of the output voltage to zero. Therefore, only the active component is contributing to the actual output voltage. The reference signal for the active component of the output voltage (u*d) is produced based on the active power component (P) with an active power vs. active voltage droop. To synchronize the frequencies of multiple converter units, a reactive power vs. frequency droop can be introduced for each converter unit, regulating the frequency based on changes in the reactive power component (Q) of each converter unit.

Abstract: A method for operation of a converter circuit is specified, wherein the converter circuit has a converter unit with a multiplicity of drivable power semiconductor switches and an LCL filter which is connected to each phase connection of the converter unit, in which method the drivable power semiconductor switches are driven by means of a drive signal which is formed from reference voltages. The reference voltages are formed by subtraction of damping voltages from reference-phase connection voltages, with the damping voltages being formed from filter capacitance currents, weighted with a variable damping factor of the LCL filter. An apparatus for carrying out the method is also specified.

Abstract: The disclosure relates to a converter control unit or power system stabilizing unit for counteracting oscillations in electric power systems that is equipped and employed to provide and processes information for system-wide monitoring, protection, control and metering. It comprises means for synchronized (e.g. via GPS or another absolute/global time reference) sampling of voltages and/or currents, means for down-sampling in order to decrease the number of samples, and means for calculating phasors, i.e. time stamped amplitude and phase angle of the voltages and/or currents.

Abstract: A switchgear cell is disclosed having a first energy store and a second energy store connected in series therewith, having a first, second, third and fourth power semiconductor switch, which are connected in series, wherein the first, second, third and fourth power semiconductor switch are in each case one drivable bidirectional power semiconductor switch with a controlled unidirectional current-conducting direction. The first power semiconductor switch is connected to the first energy store, and the fourth power semiconductor switch is connected to the second energy store. A third energy store is connected to the junction between the first and the second power semiconductor switch and the junction between the third and the fourth power semiconductor switch.

Abstract: A method is disclosed for operating a converter circuit, with the converter circuit having a converter unit with a plurality of drivable power semiconductor switches and an LCL filter connected to each phase connection of the converter unit, in which the drivable power semiconductor switches are driven by means of a drive signal which is formed from a hysteresis power value, from a hysteresis wattless-component value and from a selected flux sector. An apparatus for carrying out the method is also disclosed.

Abstract: A converter unit is disclosed which produces an output voltage based on reference signals (u*d, u*q) that are generated from active and reactive components (P, Q) of the converter's output power. A first reference signal for a reactive component of the output voltage (u*q) is set to zero, thus regulating the reactive component of the output voltage to zero. Therefore, only the active component is contributing to the actual output voltage. The reference signal for the active component of the output voltage (u*d) is produced based on the active power component (P) with an active power vs. active voltage droop. To synchronize the frequencies of multiple converter units, a reactive power vs. frequency droop can be introduced for each converter unit, regulating the frequency based on changes in the reactive power component (Q) of each converter unit.

Abstract: An exemplary method comprises the steps of introducing a reactive current reference square wave, detecting load voltage changes at every change in the reactive current reverence wave, and determining whether the detected load voltage changes exceed a predefined islanding detection threshold value, indicating a loss of mains and an islanding operation of the power generator. With the exemplary loss-of-mains detection, islanding can be detected within a shortest period of time, even if the local islands active and reactive load matches exactly the distributed generators active and reactive power generation. So even without a sudden voltage change, unintentional islanding can immediately be detected and control electronics can safely turn of the distributed power generator.

Abstract: A converter circuit having a first and a second converter element is specified, with each converter element having a DC voltage circuit and in each case one converter element phase (u1, v1, w1) of the first converter element being connected to a respective converter element phase (u2, v2, w2) of the second converter element. Furthermore, a transformer is provided, with the secondary windings of the transformer being connected to the connected converter element phases (u1, v1, w1, u2, v2, w2) of the first and second converter elements.

Abstract: A method is disclosed for operating a converter circuit, with the converter circuit having a converter unit with a plurality of drivable power semiconductor switches and an LCL filter connected to each phase connection of the converter unit, in which the drivable power semiconductor switches are driven by means of a drive signal which is formed from a hysteresis power value, from a hysteresis wattless-component value and from a selected flux sector. An apparatus for carrying out the method is also disclosed.

Abstract: A method for operation of a converter circuit is specified, wherein the converter circuit has a converter unit with a multiplicity of drivable power semiconductor switches and an LCL filter which is connected to each phase connection of the converter unit, in which method the drivable power semiconductor switches are driven by means of a drive signal which is formed from reference voltages. The reference voltages are formed by subtraction of damping voltages from reference-phase connection voltages, with the damping voltages being formed from filter capacitance currents, weighted with a variable damping factor of the LCL filter. An apparatus for carrying out the method is also specified.

Abstract: A converter circuit having a first and a second converter element is specified, with each converter element having a DC voltage circuit and in each case one converter element phase (u1, v1, w1) of the first converter element being connected to a respective converter element phase (u2, v2, w2) of the second converter element. Furthermore, a transformer is provided, with the secondary windings of the transformer being connected to the connected converter element phases (u1, v1, w1, u2, v2, w2) of the first and second converter elements.