Since a power converter including a modular multilevel converter uses a large number of cells each combining a plurality of switching elements and a DC capacitor, there is a problem of conduction loss due to the switching elements. The conduction loss is reduced by connecting a bypass circuit between terminals of each of the cells, controlling to open and close the switching element, and controlling to short-circuit the bypass circuit connected to the cell controlled to output zero voltage.

Since a power converter including a modular multilevel converter uses a large number of cells each combining a plurality of switching elements and a DC capacitor, there is a problem of conduction loss due to the switching elements. The conduction loss is reduced by connecting a bypass circuit between terminals of each of the cells, controlling to open and close the switching element, and controlling to short-circuit the bypass circuit connected to the cell controlled to output zero voltage.

A power supply system that includes a converter that converts an input alternating-current voltage into a direct-current voltage and outputs the direct-current voltage to a load. The system includes a switcher that electrically connects one of multiple alternating-current power supplies to the converter, a voltage detector that detects an input voltage input to the converter, and a current detector that detects an output current output from the converter. The switcher repeats, for a predetermined amount of time, a determination of whether there is an abnormality in alternating-current power supply based on the input voltage detected by the voltage detector. Moreover, if there is an abnormality, the switcher switches which alternating-current power supply is connected to the converter. Further, the switcher adjusts, based on the result of detection by the current detector, the amount of time for which the determination is performed.

A multi-phase network power supply with compensation for harmonic oscillations relates to electrical engineering and is intended for supplying various electrical devices connected to a multi-phase alternating-current electrical network. The technical result of the claimed solution consists in lessening harmonic components, reducing pulsations in the voltage and current output by the power supply, and significantly reducing the required power. The multi-phase alternating-current network power supply with compensation for harmonic oscillations comprises a main multi-phase rectifier of the alternating-current network, an additional multi-phase rectifier, a controller and an additional voltage or current supply, wherein the positive terminal of the main multi-phase rectifier is capable of being connected to a load, and the negative terminal of the main multi-phase rectifier is connected to the positive terminal of the additional voltage or current supply, the negative terminal of which is capable of being connected to a load, the output terminals of the additional multi-phase rectifier are connected to the input terminals of the additional voltage or current supply, wherein the additional multi-phase rectifier is equipped with electronic switches, one in the circuit of each rectifying element, and each electronic switch is connected to the controller.

A power supply system that includes a converter that converts an input alternating-current voltage into a direct-current voltage and outputs the direct-current voltage to a load. The system includes a switcher that electrically connects one of multiple alternating-current power supplies to the converter, a voltage detector that detects an input voltage input to the converter, and a current detector that detects an output current output from the converter. The switcher repeats, for a predetermined amount of time, a determination of whether there is an abnormality in alternating-current power supply based on the input voltage detected by the voltage detector. Moreover, if there is an abnormality, the switcher switches which alternating-current power supply is connected to the converter. Further, the switcher adjusts, based on the result of detection by the current detector, the amount of time for which the determination is performed.

A power transmission network, for interconnecting a variable power source and a AC electrical network including: a DC transmission link for power transmission between a network side converter and a source side converter; a AC transmission link for power transmission from the respective variable power source to a source side converter; a source side converter including: a DC connecting point operably connected to the respective transmission link; and an AC connecting point operably connected to the respective transmission link; a network side converter including: an AC connecting point for connection to the respective electrical network; and a DC connecting point operably connected to the respective transmission link; and a control system, where a network side converter is designated as a first converter, and the control system is configured to operate each first converter as a DC slack bus to vary a DC voltage at its DC connecting point.

A charging device includes a first auxiliary bridge arm and a second auxiliary bridge arm. The first auxiliary bridge arm is connected between a first port and a second module. The second auxiliary bridge arm is connected between the first port and a third module. If the AC charging power is three-phase, the first module converts a first phase of the AC charging power, and the first auxiliary bridge arm and the second auxiliary bridge arm are disabled. Consequently, the second module converts a second phase of the AC charging power, and the third module converts a third phase of the AC charging power. If the AC charging power is single-phase, at least a first module is used to convert the AC charging power.

A power supply apparatus for providing electrical power to a power consuming device or a power conversion device from at least one of a first AC power source and a second AC power source. The power supply apparatus comprises controllable rectifier devices associated with each of the first and second AC power sources. The controllable rectifier devices are controllable to simultaneously rectify and control the power provided by the first and second AC power sources.

Power supply units (PSU) provide for digital current-sharing loop control to ensure output voltage regulation during dynamic load transients by (i) delaying an internal current signal to match a delay in a shared current signal, and (ii) controlling the output amplifier based on the shared current signal and the delayed local current signal to maintain the respective local DC electrical power in proportion to contributions by other ones of the more than one PSU to the shared DC electrical power and thereby avoid instability in dynamic response to a load transient induced by the power consuming component.

Since a power converter including a modular multilevel converter uses a large number of cells each combining a plurality of switching elements and a DC capacitor, there is a problem of conduction loss due to the switching elements. The conduction loss is reduced by connecting a bypass circuit between terminals of each of the cells, controlling to open and close the switching element, and controlling to short-circuit the bypass circuit connected to the cell controlled to output zero voltage.