Abstract: A load zone of a DC system includes a connection interface for supplying the load zone with electrical energy, an electronic switch arranged between the connection interface and a DC bus, and at least two electrical devices connected in parallel to the DC bus. A voltage sensor measures a voltage across a fuse arranged between the DC bus and a respective electrical device. An evaluation unit identifies a defective device of the at least two electrical devices based on a polarity of the voltage measured by the voltage sensor across the fuse. A DC system with such a load zone and an energy source connected to the connection interface of the load zone, as well as a method for operating such load zone or DC system are also disclosed. A device is identified as being defective when the voltage measured across the fuse exceeds a specified limit 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: A method and a converter for controlling a multi-phase electric machine are disclosed. Each phase voltage of the electric machine is generated with two electronic switches interconnected to form a half bridge. The switching statuses of the half bridges are controlled with space vector modulation. A minimum dwell time is predefined, and each switching status, represented by an active basic voltage space vector, of the half bridges is maintained at least for the minimum dwell time.

Abstract: A method is disclosed for locating an earth fault in a DC network, to which multiple load zones are connectable. Each load zone has two symmetrically earthed load zone lines. In an embodiment of the method, for each load zone line, a line voltage is continuously measured between a line potential, at which the load zone line lies, and an earth potential. In the event that an earth fault is detected at a main line of the DC network, the main lines are separated from both load zone lines of a load zone and the earth fault is assigned to this load zone, if a magnitude difference between the magnitudes of the line voltages of the two load zone lines of this load zone are not significantly reduced after separating the main lines from the load zone lines.

Abstract: An electronic assembly has a printed circuit board with first and second component sides. A cooling element on the first component side is cooled by forced convection produced by a convection unit. A majority of electronic components are arranged on the second component side. Non-current-conducting plated-through holes are used to transport thermal energy generated by an electronic component from the second component side to the first component side. The thermal energy can be transported away from the printed circuit board and dissipated by means of the forced convection. A corresponding method for dissipating heat from an electronic assembly is also disclosed.

Abstract: A method is for locating a ground fault in a DC system to which a plurality of load zones can be connected. The method includes specifying a time window and, after the ground fault is detected, assigning the ground fault to a load zone which was connected to the DC system within the time window before the detection of the ground fault.

Abstract: A method is for detecting a ground fault in a load zone that can be connected to a direct-current network. The load zone includes a first load zone line connectable to a first main line of the direct-current network via a circuit breaker, and a second load zone line connectable to a second main line of the direct-current network via an interrupter switch. In an embodiment of the method, at least one line voltage at a load zone line is continually measured. If a ground fault is not detected at any main line of the direct-current network before the load zone is connected, the interrupter switch is closed while the circuit breaker is open, and a ground fault in the load zone is inferred if at least one line voltage does not significantly change after the interrupter switch is closed.

Abstract: A method for locating a ground fault in an IT network which has a converter with a rectifier connected to a power transmission network, a DC link and an inverter connected to an electrical machine includes measuring a common-mode voltage property of the converter or of the power transmission network and comparing the common-mode voltage property with an output voltage property of an output voltage of the inverter. When the IT network experiences a ground fault, the comparison of the common-mode voltage property with the output voltage property is used to determine whether a machine area of the IT network connected downstream of the converter, which includes the electrical machine and a connecting line between the electrical machine and the converter, causes the ground fault.

Abstract: An electrical supply device is connected on a network side to an electrical supply network and includes a frequency converter having a network-side power converter and an intermediate circuit, and a network filter, which is connected upstream of the network-side power converter. In a method for operating the electrical supply device, during a pulse-blocking operating state of the frequency converter, a check is carried out for the presence of a dangerous state of the network filter, and only in the presence of the dangerous state, only the network-side power converter is actuated such that a network perturbation causing the dangerous state of the network filter is at least damped to protect the network filter from the dangerous state.

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: An electronic assembly has a printed circuit board with first and second component sides. A cooling element on the first component side is cooled by forced convection produced by a convection unit. A majority of electronic components are arranged on the second component side. Non-current-conducting plated-through holes are used to transport thermal energy generated by an electronic component from the second component side to the first component side. The thermal energy can be transported away from the printed circuit board and dissipated by means of the forced convection. A corresponding method for dissipating heat from an electronic assembly is also disclosed.

Abstract: A method for operating a normally off or normally on power semiconductor element. A threshold voltage change in a threshold voltage of the power semiconductor element in relation to a reference threshold voltage is determined. A switch-on gate voltage is applied between a gate terminal and a source terminal of the power semiconductor element for the purpose of switching on the power semiconductor element is changed by the threshold voltage change in relation to a reference switch-on gate voltage corresponding to the reference threshold voltage.

Abstract: A method and a converter for controlling a multi-phase electric machine are disclosed. Each phase voltage of the electric machine is generated with two electronic switches interconnected to form a half bridge. The switching statuses of the half bridges are controlled with space vector modulation. A minimum dwell time is predefined, and each switching status, represented by an active basic voltage space vector, of the half bridges is maintained at least for the minimum dwell time.

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: A neutral point clamped inverter with an upper half-bridge and a lower half-bridge, wherein each half-bridge has an inner transistor and an outer transistor, where the inner transistor of the upper half-bridge is configured to interact with the outer transistor of the upper half-bridge such that a signal that reproduces the switch state of the inner transistor is coupled into an actuation circuit for switching the outer transistor and influences the switch state of the outer transistor.

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: 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: A method for locating a ground fault in an IT network which has a converter with a rectifier connected to a power transmission network, a DC link and an inverter connected to an electrical machine includes measuring a common-mode voltage property of the converter or of the power transmission network and comparing the common-mode voltage property with an output voltage property of an output voltage of the inverter. When the IT network experiences a ground fault, the comparison of the common-mode voltage property with the output voltage property is used to determine whether a machine area of the IT network connected downstream of the converter, which includes the electrical machine and a connecting line between the electrical machine and the converter, causes the ground fault.

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.