Abstract: An electronic switch has a first semiconductor switch arranged between a first source-side terminal and a first consumer-side terminal first, and a switch embodied as a thyristor and arranged between the first consumer-side terminal and a second source-side terminal. The switch is configured to generate a thermal overload from a short-circuit current produced when the switch closes. The thermal overload causes the first semiconductor switch to irreversibly transition into an open state due to a modification inside the first semiconductor switch caused by the thermal overload. This improves the switching behavior of the electronic switch in the event of a fault. Furthermore, an electrical network with at least one electronic switch connected to an energy source and a method for operating such an electronic switch or such an electrical network is also described.

Abstract: A frequency converter with a rectifier on an input side and a backup capacitor arranged downstream of the rectifier. Input-side phases of the rectifier feed the backup capacitor via multiple half-bridges of the rectifier. The input-side phases are connected to grid-side phases of a multiphase supply grid via a pre-circuit. Each grid-side phase is connected to an input-side phase within the pre-circuit via a phase capacitor. Each grid-side phase is additionally directly connected to another input-side phase within the pre-circuit via a switch and the grid-side phases are short-circuited with the input-side phases when the switches are closed. Each phase capacitor connects two grid-side phases or two input-side phases together. The frequency converter has a control apparatus which keeps the switches open when pre-charging the backup capacitor and closes the switches when a specified charge state of the backup capacitor is reached.

Abstract: A method is for testing the functionality of a switching member including at least one switching element. A switching state is influenced via a control input of the switching element and via a control signal generated and output to the control input. An activation signal is output to the control unit and changes the control signal. The activation signal induces a test signal as the change to the control signal and induces a disconnection pulse as the test signal. The SiC or GaN power semiconductor is switched off via the disconnection pulse and conducts current in the reverse direction. In response to the disconnection pulse, the voltage drop is recorded. A comparison is carried out between an indicator and a reference encoding an expected response to the disconnection pulse. Depending on the result of the comparison, a status signal is generated which encodes the functionality of the switching member.

Abstract: A power distributing apparatus connecting several loads to a DC voltage supply includes a number of cascaded hierarchy stages connected between the DC voltage supply and the loads. The hierarchy stages define a radial-network-type current path which branches into a number of parallel sub-paths with each additional hierarchy stage. The number of sub-paths connecting the loads corresponds to the number of connected loads. Each sub-path conducts an electric current which can be switched by a respective circuit breaker disposed in each sub-path. The value of a trigger current for each circuit breaker in each hierarchy stage increases successively from the load side toward the DC voltage supply side.

Abstract: In a method for controlling a direct current switch having first and second semiconductor switches capable of being switched off, the first and second semiconductor switches are arranged between first and second terminals to enable conduction of a current with a first polarity through the first semiconductor switch and conduction of the current with a second polarity that is opposite to the first polarity through the second semiconductor switch. One of the first and second semiconductor switches is switched off as a function of a current measurement value.

Abstract: An electronic switch for a DC voltage system includes at least two turn-off semiconductor switches, a varistor and a capacitor, and at least two diodes connected in series with opposite polarity. The turn-off semiconductor switches are connected at a connection point in series with opposite polarity between a first connection of the electronic switch and a second connection of the electronic switch. In order to provide improved overvoltage protection, the varistor and the capacitor form a series connection, with one end of the series connection connected to the connection point. A DC voltage system employing the electronic switch and a method for limiting overvoltages in the electronic switch or in a corresponding DC voltage system are also disclosed. Inductive energy of an element connected to the electronic switch is transferred to the capacitor when a limit, defined by the varistor, has been exceeded.

Abstract: The invention relates to an energy recovery rectifier device (16), in particular for an industrial plant (2), for connection to an AC system (8), comprising an energy recovery rectifier (24) and a buffer capacitor (46) that is connected in parallel to the DC side (30) of the energy recovery rectifier (24). A step-up converter (52) is connected between the buffer capacitor (46) and the energy recovery rectifier (24). The invention further relates to a method (86) for operating an energy recovery rectifier device (16) as well as to an industrial plant (2) comprising an energy recovery rectifier device (16).

Abstract: A dangerous, higher-frequency (>1 kHz) earth fault current in an electrical drive system operated in an electrical grid and having a power converter and an electrical drive machine can be prevented by producing a common-mode voltage with a defined common-mode voltage component in the power converter at a selected low frequency (<1 kHz); in the event of an earth fault in the electrical drive system, flowing at the selected low frequency a common-mode current component of a common-mode current through a predominantly ohmic conductor-to-earth impedance on the basis of the defined common-mode voltage component; measuring a total common-mode current in one of several current circuits of the electrical drive system; determining from the total current the common-mode current component; and when the common-mode current component reaches a reference value, disconnecting the electrical drive system from the electrical grid.

Abstract: The invention relates to a DC voltage network having a plurality of sections (1) which can be connected together and separated from one another individually or in groups via a respective switch element (5). A pre-charging circuit (10) has diode groups (11), a switch device (12), an energy transmission path (13), and a controller (14). Each of the sections (1) of the DC voltage network is coupled to the energy transmission path (13) via at least one respective diode group of the diode groups (11). The energy transmission path (13) is consistently the same for the diode groups (11). The controller (14) transmits a control signal (S) to the switch device (12) in order to pre-charge sections (1), and the switch device (12) thereby switches the energy transmission path (13) for all of the sections (1) coupled to the energy transmission path (13) so as to be conductive.

Abstract: A direct-current network has an infeed unit, a plurality of network sections which are each separably inter connected by respective switching elements, and a controllable current-limiting unit, which limits charge-transfer currents that flow between the network sections because of different voltages of the network sections following disconnection of the network sections from the infeed unit and before reconnection of the network sections to the infeed unit.

Abstract: In a method for controlling a direct current switch having first and second semiconductor switches capable of being switched off, the first and second semiconductor switches are arranged between first and second terminals to enable conduction of a current with a first polarity through the first semiconductor switch and conduction of the current with a second polarity that is opposite to the first polarity through the second semiconductor switch. One of the first and second semiconductor switches is switched off as a function of a current measurement value.

Abstract: A power distributing apparatus connecting several loads to a DC voltage supply includes a number of cascaded hierarchy stages connected between the DC voltage supply and the loads. The hierarchy stages define a radial-network-type current path which branches into a number of parallel sub-paths with each additional hierarchy stage. The number of sub-paths connecting the loads corresponds to the number of connected loads. Each sub-path conducts an electric current which can be switched by a respective circuit breaker disposed in each sub-path. The value of a trigger current for each circuit breaker in each hierarchy stage increases successively from the load side toward the DC voltage supply side.

Abstract: The invention relates to a DC voltage network having a plurality of sections (1) which can be connected together and separated from one another individually or in groups via a respective switch element (5). A pre-charging circuit (10) has diode groups (11), a switch device (12), an energy transmission path (13), and a controller (14). Each of the sections (1) of the DC voltage network is coupled to the energy transmission path (13) via at least one respective diode group of the diode groups (11). The energy transmission path (13) is consistently the same for the diode groups (11).

Abstract: The invention relates to an electrical DC voltage system which is coupled to at least one AC voltage network (1). A supply circuit (5) is used to convert three-phase AC voltage into DC voltage which supplies a DC voltage system. The latter contains devices (13, 14, 21, 23, 27, 22, 17, 19, 20) each having a decentralized precharge device (7). The invention also relates to a method for operating such an electrical DC voltage system on the basis of a voltage value applied to the busbar (12).

Abstract: A dangerous, higher-frequency (>1 kHz) earth fault current in an electrical drive system operated in an electrical grid and having a power converter and an electrical drive machine can be prevented by producing a common-mode voltage with a defined common-mode voltage component in the power converter at a selected low frequency (<1 kHz); in the event of an earth fault in the electrical drive system, flowing at the selected low frequency a common-mode current component of a common-mode current through a predominantly ohmic conductor-to-earth impedance on the basis of the defined common-mode voltage component; measuring a total common-mode current in one of several current circuits of the electrical drive system; determining from the total current the common-mode current component; and when the common-mode current component reaches a reference value, disconnecting the electrical drive system from the electrical grid.

Abstract: The invention relates to an energy recovery rectifier device (16), in particular for an industrial plant (2), for connection to an AC system (8), comprising an energy recovery rectifier (24) and a buffer capacitor (46) that is connected in parallel to the DC side (30) of the energy recovery rectifier (24). A step-up converter (52) is connected between the buffer capacitor (46) and the energy recovery rectifier (24). The invention further relates to a method (86) for operating an energy recovery rectifier device (16) as well as to an industrial plant (2) comprising an energy recovery rectifier device (16).

Abstract: An apparatus switches a direct current in a high-voltage line. The apparatus contains a multiplicity of switching units, which are arranged so as to form a series circuit in the high-voltage line. Each switching unit in this case contains a switching element and a surge arrester arranged in a parallel circuit with the switching element, the threshold voltage of the surge arrester being higher than a rated voltage of the switching element. A sum of the rated voltages of the switching elements corresponds at least to an operating voltage of the high-voltage line. The switching elements are mechanical switches, and each mechanical switch contains a contact arrangement having two disconnectable contact pieces and is configured to build up an arcing voltage on disconnection of the contact pieces with a magnitude which is higher than the rated voltage of the mechanical switch.

Abstract: A converter having at least one converter module, which includes a primary circuit connected to a power supply, a secondary circuit connected to a load, and a DC link circuit having an intermediate circuit capacitance, is operated according to the disclosed method by controlling the primary circuit such that the intermediate circuit voltage dropping across the intermediate circuit capacitance is adjusted to a predetermined desired voltage value which depends on the direction of the power flow in the secondary circuit.

Abstract: The invention is an optimized method for controlling a Vienna rectifier (10), comprising the following steps: on the basis of a characteristic vector—vector—a block (B1-B6) is selected from a plurality of blocks (B1-B6) in a space vector switching diagram for the Vienna rectifier (10), depending on the block (B1-B6) selected and its position in the space vector switching diagram, the vector is rotated through an offset angle according to the position of the block (B1-B6) in the space vector switching diagram, wherein the resulting angle of the rotated vector continues to be used as the normalized phase angle (?) and the block (B1) in which the rotated vector falls is designated the first block (B1), on the basis of the normalized phase angle (?), an upper or lower half of the first block (B1) is selected, on the basis of the absolute value of the normalized phase angle (?) and the vector, one of three area sections (F1-F3) of the block (B1) is selected in the first block (B1), on the basis of the area sect

Abstract: A drive controller and a method for operating a drive controller having a converter with a DC link circuit, includes measuring during operation phase currents generated by the converter; forming from the measured phase currents a current vector in a first coordinate system; rotating, with a first transformation angle and with a first rate of change, the current vector into a second coordinate system to generate a resulting current vector; supplying the resulting current vector to a regulator to generate a resulting voltage vector at an output of the regulator; rotating, with the first transformation angle or with a second transformation angle rotating at the first rate of change, the resulting voltage vector back into the first coordinate system to generate a resulting back-transformed voltage vector; and using the resulting back-transformed voltage vector as an influencing variable in addition to U/f control or vector regulation for controlling the converter.