A first voltage source converter and converter station including such a first voltage source converter, as well as a method and computer program product for controlling the first voltage source converter are disclosed. The first voltage source converter has a DC side for connection to a DC system, has an AC side for connection to an AC system and is interconnected with an AC side of a second voltage source converter, which has a DC side connected to the DC system. The first voltage source converter includes a number of converter valve pairs, each being connected to a corresponding AC phase of the AC system and a control unit controlling the converter valves to generate at least one AC waveform and to reduce oscillations between the converters.

A modular power converter includes first and second terminals to connect to electrical networks and at least one module connected between the first and second terminals, the module(s) including at least one switching element and at least one energy storage device, the switching element(s) and the energy storage device(s) combining to selectively provide a voltage source, the switching element(s) being switchable to transfer power between the first and second terminals. The converter further includes a control unit configured to selectively control switching of the switching element(s) to store energy from or release energy to either or both of the first and second terminals so as to decouple respective power flows at the first and second terminals and thereby inhibit a modulation of power flow at one of the first and second terminals from modifying a power flow at the other of the first and second terminals.

The disclosure relates to a line commutated converter, LCC, for a high-voltage direct current, HVDC, power converter. The LCC comprises at least one bridge circuit for connection to at least one terminal of a DC system. Each bridge circuit comprises at least two arms, and each arm is associated with a phase of an AC system. Each arm comprises one or more upper thyristor valves and one or more lower thyristor valves connected in series, and a branch extending from between the upper and lower thyristor valves. Each arm further comprises a parallel capacitor module comprising at least one parallel capacitor being connected in parallel between at least one pair of branches comprising a first branch and a second branch wherein during commutation of a flow of current in the first branch to a flow of current in the second branch, the at least one parallel capacitor is configured to discharge current in to the second branch in the same direction as the flow of current in the second branch.

A power supply has first and second ac voltage generators. Both of the first and second ac voltage generators are connected to one or more loads and a respective 6-pulse rectifier unit for rectifying ac voltage from each of the first and second power generators to a dc voltage output for the loads, Both of the first and second ac voltage generators includes two 3-phase voltage sources separated by a phase shift. The voltage output from each rectifier unit is coupled to the loads via a respective interphase inductor.

A transport refrigeration unit (TRU) system (IO) is provided. The TRU system includes a TRU (30), an electrical grid and a control unit. The TRU (30) is configured to be operably coupled a container (20) and includes components configured to control an environment within an interior of the container (20) and a TRU battery pack (40) configured to store energy for powering at least the components. The control unit is communicative with the TRU (30) and the electrical grid and is configured to manage power supplies and demands between the TRU battery pack (40) of each TRU (30) and the electrical grid.

A power transmission network including: a variable power source; an AC transmission link for AC power transmission from the variable power source to at least one source side converter; at least one source side converter including: an AC connecting point operably connected to the AC transmission link; and a DC connecting point for connection to a DC transmission link; and a control system configured to operate the source side converter or at least one of the source side converters in a frequency damping mode to control an AC voltage at its AC connecting point and thereby damp at least one frequency component at its AC connecting point and/or in the AC transmission link.

A method of clearing a fault in a high voltage DC electrical network, including power converters interconnected by a DC power transmission, comprising: detecting a fault in the DC power transmission and reconfiguring each power converter to a fault blocking mode driving the DC fault current towards zero; locating the fault and isolating a faulty portion from a healthy remaining portion; reconfiguring one of the power converters designated as a re-energising power converter from the fault blocking to re-energise the healthy remaining portion; and detecting a rise in the voltage level in the healthy remaining portion above a threshold level and reconfiguring the remaining power converter connected with the healthy remaining portion from the fault blocking to the normal power transmission.

A power supply has first and second ac voltage generators. Both of the first and second ac voltage generators are connected to one or more loads and a respective 6-pulse rectifier unit for rectifying ac voltage from each of the first and second power generators to a dc voltage output for the loads, Both of the first and second ac voltage generators includes two 3-phase voltage sources separated by a phase shift. The voltage output from each rectifier unit is coupled to the loads via a respective interphase inductor.

A power transmission network is disclosed, which includes an AC electrical network connected to a point of common coupling, the point of common coupling being connectable to a further electrical device; and a processing circuit configured to receive and process a voltage of the point of common coupling to determine a phase difference between the voltages of the AC electrical network and the point of common coupling during an exchange of power between the AC electrical network and the point of common coupling.

The present invention discloses a charging method for a sub-module based hybrid converter. By setting a half-controlled charging link of half-blocking all full bridge sub-modules in a charging process, and raising the voltages of half bridge sub-modules to reach the starting point of a half bridge sub-module based self-powered supply in an uncontrolled stage of the half bridge sub-modules, the starting point of the sub-module based self-powered supply is increased, and the design difficulty of the sub-module based self-powered supply is reduced. The present invention also discloses another charging method for a sub-module based hybrid converter. The above objective can also be achieved by setting a half-controlled charging link of bypassing all full bridge sub-modules in the charging process.