A converter module for power converter stations includes a first terminal for input/output of an electrical current to the converter module via a first connection line, a second terminal for output/input of the current from the converter module via a second connection line, and a by-pass switch connected between the first terminal and the second terminal. The converter module further includes a first switching module and a second switching module connected in series via a first node connected to either one of the first terminal and the second terminal and at least two capacitor units. The first switching module includes two switching devices and the second switching module is connected between the first node and a second node. In the converter module, a first capacitor unit is connected from the second node to a first switching device of the first switching module and a second capacitor unit is connected from the second node to a second switching device of the first switching module to form two separate current paths between the first node and the second node. Accordingly, a reduction of the energy discharge is obtained upon failure of one or more of the switching devices or modules.

Disclosed is a phase-shifted square wave modulation technique for single-phase and three-phase IM2DC applications in HVDC/MVDC systems. A square wave based modulation waveform is applied to each cell of IM2DC and compared to the phase-shifted carrier waveforms to generate device gate signals. As a result, a higher equivalent switching frequency can be achieved, and square wave based arm and AC link waveforms will be generated. In addition, power flow of IM2DC can be controlled by a phase shift angle of the square modulation waveforms between HVS and LVS. The converter cell capacitors can be reduced in size because they are only required to smooth high switching frequency ripple components. In addition, lower TDR can be achieved due to the higher power transferring capability of square waves.

An inverter-charger combination includes plurality of first and second switching elements, a capacitor, and a dual active bridge, connected in parallel to one another. The first and the second switching elements are connected in series to form switching subassemblies that are disposed in parallel and are connected to an AC source. Each of the first and the second switching elements has a first and a second contactor, and, when the first contactor is open and the second contactor is closed, an electric current flows from a rechargeable energy storage system (RESS) in direct current form to a load in AC form through the switching subassemblies to provide power to the load, and when the first contactor is closed and the second contractor is open, an electric current flows from the AC source in AC form to the RESS in DC form through the switching subassemblies to charge the RESS.

A bidirectional DC converter assembly includes two serially-arranged DC/DC converters. The first converter is a buck (or a buck/boost) converter to be connected to a high-voltage (HV) level of an electric vehicle. The second converter is a series resonant switching converter to be connected to a low-voltage (LV) of the vehicle. The series resonant switching converter of the second converter is formed by a DC/AC converter, a transformer, and an AC/DC converter, which are serially arranged in the stated order between the first converter and the LV level. A bidirectional peak current controller is associated with the first converter. The peak current controller is realized by a current measurement at an inductor of the first converter. The peak current controller uses the coil current value, which is modified with an offset value and thus has a constant sign, as a set point in controlling the first converter.

A phase leg for a multilevel inverter includes a first direct current lead, an outer solid-state switch, an inner solid-state switch, and a midpoint-clamping device. The outer solid-state switch device is connected to the first direct current lead. The inner solid-state switch is connected in series with the outer solid-state switch. The midpoint-clamping device is a bi-directional current flow device connected between a second DC lead and a node between the inner and outer solid-state switches for reducing conduction losses associated with current flowing through the phase leg.

A current flow control assembly, for controlling current flow in an electrical network of interconnected electrical elements, having: current flow controllers, each current flow controller connectable to at least one of the interconnected electrical elements, and being configured to control current flow in at least one of the interconnected electrical elements within a current flow control range; a control unit in communication with each of the current flow controllers, wherein the control unit is configured to: select at least one of the current flow controllers with a flow control range that corresponds to one or more current flow control requirements of the electrical network; and operate the selected current flow controller to control current flow in at least one of the interconnected electrical elements to control current flow in the electrical network in accordance with the current flow control requirement of the electrical network.

Provided are a control unit having a first control state in which a first switching element and a second switching element of one series circuit are turned on and a second control state to which the first control state shifts and in which a first switching element of another series circuit and the second switching element of the one series circuit are turned on, and executing control so as to apply predetermined voltage to the other side of a transformer during a predetermined time period during the first control state before shifting to the second control state.

Provided are a control unit having a first control state in which a first switching element and a second switching element of one series circuit are turned on and a second control state to which the first control state shifts and in which a first switching element of another series circuit and the second switching element of the one series circuit are turned on, and executing control so as to apply predetermined voltage to the other side of a transformer during a predetermined time period during the first control state before shifting to the second control state.

A converter includes first and second DC terminals for connection to a DC network, limb(s) connected between the first and second DC terminals, and a controller. Each limb includes a phase element and DC side sub-converter(s). The phase element has switching elements and AC terminal(s) for connection to an AC network, the switching elements being switchable to selectively interconnect a DC side voltage at a DC side of the phase element and an AC side voltage at an AC side of the phase element, The DC side sub-converter(s) connected to the DC side of the phase element. The controller selectively controls the switching elements and the operation of each DC side sub-converter as a voltage synthesiser. The controller also controls the switching elements to provide a blocking voltage to limit or block the flow of a fault current between the AC and DC networks and through each limb.

A reversible converter includes a first field effect transistor and a second field effect transistor coupled in series between a first terminal and a second terminal for a DC voltage. A first thyristor and a second thyristor are coupled in series between the first and second terminals for the DC voltage. A third thyristor and a fourth thyristor are also coupled in series between the first and second terminals for the DC voltage terminals, but have an opposite connection polarity with respect to the first and second thyristors. A midpoint of connection between the first and second field effect transistors and a common midpoint of connection between the first and second thyristors and the third and fourth thyristors are coupled to AC voltage terminals. Actuation of the transistors and thyristors is controlled in distinct manners to operate the converter in an AC-DC conversion mode and a DC-AC conversion mode.