Abstract: A device for converting an electric current has a phase module, which in turn has an alternating current connection and at least one direct current connection connected to an intermediate direct current circuit. The device further has an energy accumulator. A phase modulation path is formed between each direct current connection and each alternating current connection. Each phase modulation path has a series connection of submodules, which each have a power semiconductor. A semiconductor protective device is provided in parallel connection to power semiconductors of each submodule. A control unit actuates the semiconductor protective device, and energy accumulator(s) are equipped for supplying energy to the control unit. The device safely prevents damage from a short circuit on the direct-current side, even when the supply grid is connected, because a direct current connection of each phase module is connected to the intermediate direct current circuit via a direct-current switch.

Abstract: A device for converting an electric current includes at least one phase module having an AC terminal and at least one DC terminal. Phase module branches, each of which is equipped with serially connected submodules, are respectively provided between each DC terminal and each AC terminal. Each submodule is provided with at least one power semiconductor. Semiconductor protecting means are connected in parallel or in series to at least one of the power semiconductors to enable the device to withstand even high short-circuit currents for a sufficient period of time. A method for protecting the power semiconductors of the device, is also provided.

Abstract: A device for converting an electrical current includes at least one phase module with an AC connection and at least one DC connection. A phase module branch is provided between each DC connection and each AC connection. Each phase module branch has a series connection made of sub-modules, which in turn include an energy accumulator each and at least one power semiconductor. Measuring sensors provide actual values and there are provided control means connected to the measuring sensors. The control can be easily adapted to any arbitrary number of sub-modules in each phase module branch. The control means include a current regulating unit and control units associated with a phase module branch each, wherein the current regulating unit is configured to provide branch target values for the control units. The control units are designed to produce control signals for the sub-modules.

Abstract: A method for charging and/or discharging energy storage devices is performed in a multilevel converter including at least one phase module branch having a series circuit of submodules each with at least one power semiconductor circuit for connection or disconnection of an energy storage device in a circuit parallel to the power semiconductor circuit and a submodule sensor for detection of an energy storage actual value. An energy change state is obtained and a determination is made as to whether connected energy storage devices in a phase module branch can be charged or discharged. The next energy storage device to be switched in each phase module branch is selected by predetermined logic dependent on an energy change state, through which energy stored in energy storage devices is kept approximately at the same level. A high clock rate is simultaneously avoided for connection and disconnection of the selected energy storage device.

Abstract: A device for inverting an electric current has at least one phase module which has an alternating current connection and at least one direct current connection. Semiconductor valves having semiconductor modules are connected in series and are provided for switching the electric current between the alternating current connection and each direct current connection. At least one power storage device is provided for storing electrical power. In order to provide such a device, with which the adverse effects of a bridging short circuit are reliably and effectively reduced, it is proposed that each semiconductor module has semiconductor groups connected in parallel to each other, wherein each semiconductor group of the semiconductor module is connected via its own separate semiconductor current path to at least one of the power storage devices.

Abstract: A converter has at least one phase module, an AC voltage terminal and a DC voltage terminal. A phase module branch is formed between each DC voltage terminal and each AC voltage terminal. Each phase module branch has a series circuit containing submodules which each have a capacitor, a power semiconductor, and submodule sensors for detecting energy stored in the capacitor and with a regulation device for regulating the apparatus in dependence on energy values and predetermined desired values. Therefore unbalanced loading of the energy storage units is avoided. The regulation device has a summation unit for summing the energy values while obtaining branch energy actual values and a device for calculating circuit current desired values in dependence on the branch energy actual values. The regulation device compensates for imbalances in the branch energy actual values in dependence on the circuit current desired values.

Abstract: In order to form an overcurrent switching apparatus for medium-voltage or high-voltage applications with a current detection device for changing over a contact system associated with them from a first state to a second state in the event of a threshold current being exceeded, the switching properties of which overcurrent switching apparatus are precise, an actuating device is disposed downstream of the current detection device, which is in a first current branch, via a coupling device. The actuating device is configured to change over the contact system, which is in a second current branch, from the first to the second state.

Abstract: A power semiconductor module for energy distribution, includes at least one power semiconductor, connection terminals for connecting the power semiconductor module, and a housing, in which protection from explosion is ensured in the module even in the event of electric arcs. Therefore, each power semiconductor and each connection terminal is disposed in the housing, and the housing includes an exhaust gas channel for the controlled withdrawal of hot gases and/or plasma in the event of an explosion.

Abstract: An arbitrary voltage distribution can be achieved in a high-voltage generator which supplied an X-ray tube having a metallic central part, wherein the anode voltage and the cathode voltage are generated in the high-voltage generator by two series-connected high-voltage rectifiers with respective preceding high-voltage transformers, whereby the high-voltage transformers being supplied by an inverse rectifier. A clocked switch, via which the average value of the anode current can be set and matched to the cathode current, lies in the lead to the high-voltage transformer at the anode side.