A semiconductor switching string includes a plurality of series-connected semiconductor switching assemblies, each having a main semiconductor switching element that includes first and second connection terminals. The main semiconductor switching element also has an auxiliary semiconductor switching element electrically connected between the first and second connection terminals. Each semiconductor switching assembly also includes a control unit configured to switch on a respective auxiliary semiconductor switching element to selectively create an alternative current path between the first and second connection terminals whereby current is diverted to flow through the alternative current path to reduce the voltage across the corresponding main semiconductor switching element. The or each control unit is further configured to switch on the auxiliary semiconductor switching element when the voltage across the corresponding main semiconductor switching element differs from a voltage reference derived from the voltage across all of the main semiconductor switching elements.

A method of starting an aircraft having at least a first starter/generator (S/G) and a second S/G using at least one inverter/converter and at least one of an AC power source and a first DC power source, the method includes selectively starting at least one of the first S/G or second S/G in an AC start mode and in a DC start mode.

A method of starting an aircraft having at least a first starter/generator (S/G) and a second S/G using at least one inverter/converter and at least one of an AC power source and a first DC power source, the method includes selectively starting at least one of the first S/G or second S/G in an AC start mode and in a DC start mode.

In a power conversion system in which one or more converter cells are connected in series to form an arm for each phase, a control device includes a voltage command generating unit for generating a positive arm voltage command and a negative arm voltage command for each phase. The voltage command generating unit includes an AC current control unit, a circulating current control unit, and a command distributing unit. On the basis of inputted voltage commands, the command distributing unit subtracts voltage drop portions due to inductance values in the arms from respective voltages assigned as outputs of the positive arm and the negative arm, to distribute voltage components, thereby determining the positive arm voltage command and the negative arm voltage command.

In a power conversion system in which one or more converter cells are connected in series to form an arm for each phase, a control device includes a voltage command generating unit for generating a positive arm voltage command and a negative arm voltage command for each phase. The voltage command generating unit includes an AC current control unit, a circulating current control unit, and a command distributing unit. On the basis of inputted voltage commands, the command distributing unit subtracts voltage drop portions due to inductance values in the arms from respective voltages assigned as outputs of the positive arm and the negative arm, to distribute voltage components, thereby determining the positive arm voltage command and the negative arm voltage command.

The invention generally relates to methods and circuits for controlling switching of parallel coupled power semiconductor switching devices (3), for example for use in a power converter. In an example, there is provided a circuit for controlling switching of parallel coupled power semiconductor switching devices (3), the circuit comprising: a plurality of drive modules (2), each said module for controlling a said power semiconductor switching device (3); control circuitry to transmit switch command signals to the modules, each said switch command signal to trigger a said drive module to control a said power semiconductor switching device to switch state; and voltage isolation between the drive modules and the control circuitry, wherein each said drive module for controlling a said device comprises: timing circuitry (22) to compare a switching delay of the device and a reference delay, wherein said switching delay is a time interval between detecting a said switching command signal at the drive module and switching of the device in accordance with the detected switching command signal; and delay circuitry (21) to provide a controllable delay to delay a said triggering by a said switching command signal received at the module subsequent to the detected switching command signal, the delay circuitry configured to control the controllable delay according to a result of said comparison of said switching delay of the device, to thereby reduce a time difference between the reference delay and a said switching delay of the device switching in accordance with the subsequent switching command signal.

The disclosure relates to a balancing system for a network. The system includes a network input for detecting balancing requirements, and a transformer that includes a first winding connected to the output of the network input. The system also includes an inverter connected to a second winding of the transformer, a set of batteries connected to the inverter, and a supervision unit configured to activate the inverter and to charge or discharge the batteries when an imbalance is measured on said network. The system further includes an additional inverter connected to a third winding of the transformer, the output of which is used to supply power to at least one charging socket of an electric vehicle. The supervision unit is configured to activate the additional inverter when a charging requirement is detected at the charging socket and the requirements for injection into the network are less than a threshold value.

The invention provides the system supporting variable speed drive comprising a three-sided service cabinet embodiment. The cabinet comprising two heat exchange circuits limited by the basic elements of the cabinet embodiment, the first of which is configured to interact with an external environment and with the second heat exchange circuit, wherein the second heat exchange circuit which is configured without an ability to interact with the external environment includes a sealed cell for installing power electronics and the cell for installing a power connection and the cell for installing a measurement equipment. The cabinet comprising a dust and moisture filter, a plate heat exchanger, and a moisture removal device. The cabinet may be assembled with joined end-to-end metal sheets with curved joined ends which form strengthening ribs. The system supporting variable speed drive further comprising a cell for installing a passive filter or a filter compensation device or a capacitor bank preconfigured for compliance with variable speed drive and configured in such a way that it is dismountable in a form of a cabinet of the same height and depth as the cabinet of variable speed drive and closely aligned with the cabinet of variable speed drive. The cell for installing a power connection located on a side of the cell for installing a passive filter or a filter compensation device or a capacitor bank, wherein all connections between the cabinet of variable speed drive and the cell for installing a passive filter or a filter compensation device or a capacitor bank are made in the internal part of the embodiment.

The invention provides the system supporting variable speed drive comprising a three-sided service cabinet embodiment. The cabinet comprising two heat exchange circuits limited by the basic elements of the cabinet embodiment, the first of which is configured to interact with an external environment and with the second heat exchange circuit, wherein the second heat exchange circuit which is configured without an ability to interact with the external environment includes a sealed cell for installing power electronics and the cell for installing a power connection and the cell for installing a measurement equipment. The cabinet comprising a dust and moisture filter, a plate heat exchanger, and a moisture removal device. The cabinet may be assembled with joined end-to-end metal sheets with curved joined ends which form strengthening ribs. The system supporting variable speed drive further comprising a cell for installing a passive filter or a filter compensation device or a capacitor bank preconfigured for compliance with variable speed drive and configured in such a way that it is dismountable in a form of a cabinet of the same height and depth as the cabinet of variable speed drive and closely aligned with the cabinet of variable speed drive. The cell for installing a power connection located on a side of the cell for installing a passive filter or a filter compensation device or a capacitor bank, wherein all connections between the cabinet of variable speed drive and the cell for installing a passive filter or a filter compensation device or a capacitor bank are made in the internal part of the embodiment.

The present invention provides a method for managing power in an electrical power distribution network. The method includes, in one or more electronic processing devices: determining parameter values of one or more operating parameters of an alternating current (AC) source; determining target parameter values of the one or more operating parameters; determining a difference between the parameter values and target parameter values; and, generating a control signal based at least in part on the determined difference to control an inverter and thereby selectively cause power flow between a direct current (DC) energy storage apparatus and the AC source, the power flow causing the parameter values to tend towards the target parameter values.