The present invention provides a bidirectional high frequency speed drive configured to connect to a utility grid and an electrical machine. The bidirectional high frequency variable speed drive comprises a plurality of inductors each configured to connect to respective phase outputs of the electrical machine, a first plurality of power switches connected to the plurality of inductors, a second plurality of power switches connected to the plurality of inductors, and a controller connected to the first and second plurality of power switches. The controller can generate control signals based on an operating status and a predetermined operating status of the electrical machine. The first output of the first plurality of power switches can be interleaved to a second output of the second plurality of power switches. The present invention also provides methods for the bidirectional high frequency speed drive and apparatuses used to perform the methods of the present invention.

The present invention provides a bidirectional high frequency speed drive configured to connect to a utility grid and an electrical machine. The bidirectional high frequency variable speed drive comprises a plurality of inductors each configured to connect to respective phase outputs of the electrical machine, a first plurality of power switches connected to the plurality of inductors, a second plurality of power switches connected to the plurality of inductors, and a controller connected to the first and second plurality of power switches. The controller can generate control signals based on an operating status and a predetermined operating status of the electrical machine. The first output of the first plurality of power switches can be interleaved to a second output of the second plurality of power switches. The present invention also provides methods for the bidirectional high frequency speed drive and apparatuses used to perform the methods of the present invention.

An electric power retention distribution cell apparatus and method of operation of the cell includes a rechargeable battery assembly, a bi-directional inverter and a switch control operatively connectable to an electric utility grid, an outside power charging supply and at least one end user wherein the cell is selectively switched between the electric utility grid and the battery assembly to supply electric power to the one or more end users. The cell is connected to the power charging supply for charging the battery assembly, and for dividing the battery assembly into groups of batteries for storage at a lower terminal output voltages of each group than the battery assembly output voltage when in use as the primary power supply. Electric power supply networks are also described for a utility hub network formed using two or more cells, and for a regional utility hub network formed using multiple utility hubs.

A downhole tool and a method for operating the downhole tool are disclosed. A first power signal is supplied to the downhole tool from a power source at a first frequency. A bidirectional chopper at the downhole tool chops the first power signal to generate a second power signal having a second frequency greater than the first frequency. The second power signal is used to operate the downhole tool.

In the field of high voltage direct current power transmission networks, a voltage source converter comprises first and second DC terminals for connection to a DC electrical network, and a plurality of single-phase limbs. Each single-phase limb includes a phase element, and each phase element includes at least one switching element configured to interconnect a DC voltage and an AC voltage. An AC side of each phase element is connectable to a respective phase of a multi-phase AC electrical network, and each single-phase limb is connected between the first and second DC terminals. The voltage source converter further comprises a controller configured to determine independently of one another an amount of active power (P.sub.ref ) that the voltage source converter should exchange with the AC electrical network and an amount of reactive power (Q.sub.ref) that the voltage source converter should exchange with the AC electrical network.

An inverter system includes an input inverter including a positive and a negative DC input terminals and first and second AC output terminals; and a bidirectional inverter device, including a first bidirectional subinverter and a second bidirectional subinverter. The first and second bidirectional subinverters have DC terminals that are interconnected in parallel with a DC power storage device. The first bidirectional subinverter have first and second AC terminals. The first AC terminal is connected to the first AC output terminal of the input inverter. The second bidirectional subinverter have first and second AC terminals. The first AC terminal is connected to the second AC output terminal of the input inverter. The second AC terminal of the first bidirectional subinverter and the second AC terminal of the second bidirectional subinverter are interconnected.

An inverter system includes an input inverter including a positive and a negative DC input terminals and first and second AC output terminals; and a bidirectional inverter device, including a first bidirectional subinverter and a second bidirectional subinverter. The first and second bidirectional subinverters have DC terminals that are interconnected in parallel with a DC power storage device. The first bidirectional subinverter have first and second AC terminals. The first AC terminal is connected to the first AC output terminal of the input inverter. The second bidirectional subinverter have first and second AC terminals. The first AC terminal is connected to the second AC output terminal of the input inverter. The second AC terminal of the first bidirectional subinverter and the second AC terminal of the second bidirectional subinverter are interconnected.

An energy storage device for storing energy for a stationary AC voltage grid includes a control device; and at least two switching units. Each switching unit includes multiple storage elements for storing a part of the energy, a converter having an AC voltage connection for connection to the AC voltage grid and a DC voltage connection, and a multiplexer switching device electrically connected with the DC voltage connection of the converter and with one of the storage elements via a respective storage connection. The multiplexer switching device is configured to select one of the storage connections in dependence on a selection signal generated by the control device and to electrically connect only the one storage connection selected by multiplexer switching device with the DC voltage connection of the converter. The control device is configured to control the converter of each of the at least two switching units so as to gradually reduce an energy flow between the AC voltage grid and a first one of the switching units and to correspondingly increase an energy flow between the DC voltage grid and at least one second one of the switching units until the energy flow between the AC voltage grid and the first switching unit is reduced to zero.

An energy storage device for storing energy for a stationary AC voltage grid includes a control device; and at least two switching units. Each switching unit includes multiple storage elements for storing a part of the energy, a converter having an AC voltage connection for connection to the AC voltage grid and a DC voltage connection, and a multiplexer switching device electrically connected with the DC voltage connection of the converter and with one of the storage elements via a respective storage connection. The multiplexer switching device is configured to select one of the storage connections in dependence on a selection signal generated by the control device and to electrically connect only the one storage connection selected by multiplexer switching device with the DC voltage connection of the converter. The control device is configured to control the converter of each of the at least two switching units so as to gradually reduce an energy flow between the AC voltage grid and a first one of the switching units and to correspondingly increase an energy flow between the DC voltage grid and at least one second one of the switching units until the energy flow between the AC voltage grid and the first switching unit is reduced to zero.

The disclosure relates to a method for establishing a defined state in an electrochemical system connected to an AC/DC converter via a switch disconnector to exchange electric power. At least one DC connection of the electrochemical system is connected to the AC/DC converter via the disconnecting switch. The method includes, in a first operating state, closing a first switch to establish an electric connection between the DC connections of the electrochemical system. The application additionally relates to a disconnecting device, a power converter, and to an assembly.