Abstract:
PROBLEM TO BE SOLVED: To specify a method for operating a converter circuit, and reduce thereby a harmonic component in system voltages of an AC voltage system connected with the converter circuit. SOLUTION: In the converter circuit which has a converter 2 having a large number of drivable power semiconductor switches and has a three-phase AC voltage system 1, the drivable power semiconductor switches are driven by means of a drive signal S A formed from a control signal S R , and the control signal S R is formed by adjusting an H-th harmonic component i NH of system currents to a system current set point value i NHref . In order to reduce a harmonic component in the system voltages, the system current set point value i NHref is formed by adjusting an H-th harmonic component of system voltages to a predeterminable system voltage set point value u NHref , the control difference from the H-th harmonic component of the system voltages and the system voltage set point value u NHref being weighted by a system impedance y NH determined with respect to the H-th harmonic component. COPYRIGHT: (C)2010,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To reduce a harmonic component in an alternating-current system voltage connected to a converter circuit. SOLUTION: The converter circuit has a converter unit 1 with a plurality of drivable power semiconductor switches and is connected to a three-phase alternating-current main line system, the drivable power semiconductor switches are driven by a driving signal formed from a control signal S R , and the control signal S R is formed by adjusting an H-th harmonic component i NH of the system current to a system current set point value i NHref and specifies a method to actuate the converter circuit regarding H as 1, 2, 3, .... In order to reduce the harmonic component of system voltage, the system current set point value i NHref is formed by adjusting the absolute value of an H-th harmonic component u NH of the system voltage to the absolute value of a prescribable system voltage set point value u NHref . COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
The inventive 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 inventive 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:
The device has a drive unit coupled to a generator and connected via a rectifier to a d.c. intermediate circuit, a static converter connected to the intermediate circuit with multiple a.c. output connections and a filter arrangement connected to the a.c. output connections. The filter arrangement has series filter inductances per output and a filter capacitance connected to their junction. The filter capacitors are connected to a star point. The device has a drive unit coupled to a generator (1) and connected via a rectifier (2) to a d.c. intermediate circuit (3), a static converter (4) connected to the d.c. intermediate circuit with multiple a.c. output connections (5) and a filter arrangement (6) connected to the a.c. output connections. The filter arrangement has a first filter inductance (7) per a.c. voltage connection, a second filter inductance (8) in series and a filter capacitance (9) connected to their junction. The filter capacitors are connected to a star point (10).
Abstract:
A method is specified for operation of a converter circuit, with the converter circuit having a converter unit (2) with a multiplicity of controllable power semiconductor switches, and being connected via a transformer to a three-phase electrical AC voltage power supply system (1), in which method the controllable power semiconductor switches are controlled by means of a control signal (S A) which is formed from a regulating signal (S R). In order to damp oscillations of a power supply system voltage (u G) above the fundamental frequency, a filtered power supply system current (i GTP) is formed by filtering a power supply system current (i G) using a low-pass filter characteristic, a filtered transformer inductance voltage (u LTTP) is formed by filtering a transformer inductance voltage (u LT), which is formed from the power supply system current (i G), using a low-pass filter characteristic, a filtered power supply system voltage (u GTP) is formed by filtering a power supply system voltage (U G) using a low-pass filter characteristic, and the regulating signal (S R) is formed by addition of a regulator voltage (U R), the filtered transformer inductance voltage (u LTTP) and the filtered power supply system voltage (U GTP), with the regulator voltage (U R) being formed by regulating the filtered power supply system current (i GTP) at a power supply system current nominal value (i Gref). Furthermore, an apparatus is specified for carrying out the method.
Abstract:
Método para la actuación de un circuito de convertidor, en el que el circuito de convertidor presenta una unidad de convertidor (2) con una pluralidad de conmutadores semiconductores de potencia que se pueden controlar y está unido con una red de tensión alterna eléctrica trifásica (1), en el que los conmutadores semiconductores de potencia que se pueden controlar se controlan mediante una señal de control (SA) formada por una señal de regulación (SR) y la señal de regulación (SR) se forma por regulación de un H-avo contenido de armónicos de corrientes de la red (iNH) hasta un valor teórico de corriente de la red (iNHref), en el que H = 1, 2, 3,..., caracterizado porque el valor teórico de corriente de la red (i NHref) se forma por regulación de un H-avo contenido de armónicos de tensiones de la red (u NH) hasta un valor teórico de tensión de la red (u NHref) que se puede predefinir, en el que la variable activa (uNHdif) a partir del H-avo contenido de armónicos de las tensiones de la red (uNH) y el valor teórico de tensión de la red (uNHref) se pondera por una impedancia de la red (yNH) determinada con respecto al H-avo contenido de armónicos.
Abstract:
The method involves operating a converter circuit which has an inverter (2) with a variety of controllable power switches and is connected to a three-phase alternating current electric power (1). The current power being a H-th harmonic component of mains power (UNH) is formed of a predetermined power. An error signal is provided from the H-system harmonic component of mains power and the power is weighted with respect to the H-th harmonic component network impedance (yNH). An independent claim is included for device for carrying out the method.
Abstract:
The invention specifies a method for operating a converter circuit, the converter circuit having a converter unit (2) with a large number of drivable power semiconductor switches and with a three--phase electrical AC voltage system, in which the drivable power semiconductor switches are driven by means of a drive signal (SA) formed from a control signal ((SR), and the control signal (SR) is formed by adjusting an H-th harmonic component of system currents (i NH) to a system current setpoint value (i NHref), where H=1, 2, 3, .... In order to reduce a harmonic component in the system voltages, the system current setpoint value (i NHref is formed by adjusting an H-th harmonic component of system voltages (u NH) to a predeterminable system voltage setpoint value (U NHref), the control difference (U nHdiff) from the H-th harmonic component of the system voltages (U NH) and the system voltage setpoint value (U NHref) being weighted by a system impedance (Y NH) determined with respect to the H-th harmonic component. In addition, the invention specifies an apparatus for implementing the method.
Abstract:
A method for operating a converter circuit is specified, wherein the converter circuit has a converter unit (2) with a plurality of drivable power semiconductor switches and is connected to a three-phase electrical AC voltage network (1) by means of a transformer, in which method the drivable power semiconductor switches are driven by means of a drive signal (SA) formed from a control signal (SR). In order to attenuate oscillations of a network voltage (UG) above the fundamental frequency, a filtered network current (iGTP) is formed by means of filtering according to a low-pass characteristic of a network current (iG), a filtered transformer inductance voltage (ULTTP) is formed by means of filtering according to a low-pass characteristic of a transformer inductance voltage (uLT) formed from the network current (iG), a filtered network voltage (UGTP) is formed by means of filtering according to a low-pass characteristic of a network voltage (uG), and the control signal (SR) is formed by adding a controller voltage (uR), the filtered transformer inductance voltage (ULTTP) and the filtered network voltage (UGTP), wherein the controller voltage (uR) is formed by adjusting the filtered network current (iGTP) to a desired network current value (iGref). An apparatus for carrying out the method is also specified.