The invention relates to a method for controlling a converter connected to an electric machine by a cable (Cx) via a filter (F), said method consisting in determining at least one sequence of a plurality of voltage pulses forming a square wave signal to be applied to each conductor so as to minimize an overvoltage level, said sequence comprising a number 2N of successive pulses, N being greater than or equal to 1, each pulse being defined by a distinct rank n, said sequence being generated such that each increasing voltage pulse of rank n exhibits a pulse width that is identical to that of a decreasing voltage pulse of rank equal to 2N+1n, and the method includes the following steps in particular: determining the number of successive pulses of said sequence; determining the width of each pulse of the sequence made suitable for minimizing the overvoltage level across the terminals of the electric machine (M).

The invention relates to a method for controlling a converter connected to an electric machine by a cable (Cx) via a filter (F), said method consisting in determining at least one sequence of a plurality of voltage pulses forming a square wave signal to be applied to each conductor so as to minimize an overvoltage level, said sequence comprising a number 2N of successive pulses, N being greater than or equal to 1, each pulse being defined by a distinct rank n, said sequence being generated such that each increasing voltage pulse of rank n exhibits a pulse width that is identical to that of a decreasing voltage pulse of rank equal to 2N+1n, and the method includes the following steps in particular: determining the number of successive pulses of said sequence; determining the width of each pulse of the sequence made suitable for minimizing the overvoltage level across the terminals of the electric machine (M).

Accordingly, the embodiments herein provide a hybrid modular multilevel converter. The hybrid modular multilevel converter includes one or more chain links, one or more high voltage switches and a plurality of inductors. The one or more chain links are formed by sub modules. The one or more high voltage switches are formed by semi-controlled devices or fully controlled or any other suitable semiconductor devices. The plurality of inductors are arranged in the one or more chain links to limit circulating current among the one or more chain links. The one or more chain links are configured to enhance a power handling capability of the hybrid modular multilevel converter.

Accordingly, the embodiments herein provide a hybrid modular multilevel converter. The hybrid modular multilevel converter includes one or more chain links, one or more high voltage switches and a plurality of inductors. The one or more chain links are formed by sub modules. The one or more high voltage switches are formed by semi-controlled devices or fully controlled or any other suitable semiconductor devices. The plurality of inductors are arranged in the one or more chain links to limit circulating current among the one or more chain links. The one or more chain links are configured to enhance a power handling capability of the hybrid modular multilevel converter.

A zero-sequence current balancer for a controlling zero-sequence current in a three-phase power system includes a zig-zag transformer coupled to the three-phase power system, an inverter coupled to an output of the zig-zag transformer, and at least one of: (i) a clamp device operating as a normally open switch, the clamp device being provided in between the output of the zig-zag transformer and a neutral conductor (which may be grounded) and being connected in parallel with the inverter, and (ii) a load-break switch provided between the output end of the zig-zag transformer and an input of inverter. A controller is structured and configured to detect a fault condition in the three-phase power system, and in response cause at least one of the closing of the clamp device or the opening of the load-break switch in order to protect the system.

The invention relates to a method for controlling a converter connected to an electric machine by a cable (Cx) via a filter (F), said method consisting in determining at least one sequence of a plurality of voltage pulses forming a square wave signal to be applied to each conductor so as to minimize an overvoltage level, said sequence comprising a number 2N of successive pulses, N being greater than or equal to 1, each pulse being defined by a distinct rank n, said sequence being generated such that each increasing voltage pulse of rank n exhibits a pulse width that is identical to that of a decreasing voltage pulse of rank equal to 2N+1n, and the method includes the following steps in particular: determining the number of successive pulses of said sequence; determining the width of each pulse of the sequence made suitable for minimizing the overvoltage level across the terminals of the electric machine (M).

The invention relates to a method for controlling a converter connected to an electric machine by a cable (Cx) via a filter (F), said method consisting in determining at least one sequence of a plurality of voltage pulses forming a square wave signal to be applied to each conductor so as to minimize an overvoltage level, said sequence comprising a number 2N of successive pulses, N being greater than or equal to 1, each pulse being defined by a distinct rank n, said sequence being generated such that each increasing voltage pulse of rank n exhibits a pulse width that is identical to that of a decreasing voltage pulse of rank equal to 2N+1n, and the method includes the following steps in particular: determining the number of successive pulses of said sequence; determining the width of each pulse of the sequence made suitable for minimizing the overvoltage level across the terminals of the electric machine (M).

The invention relates to power supply systems. There is provided an apparatus and a method for supplying electric power to an electric device. In the method an indication of a desired power level to be supplied to the electric device is obtained. Electric power is received as DC power by a constant current regulator unit, which inverts the DC power to AC power and supplies the AC power to a reactance (T1) to be transformed to an output power. The output power is supplied from the reactance (T1) to the electric device. The method further comprises adjusting the AC power supplied to the reactance (T1) by using at least two of the following: voltage level of the AC power; the frequency of the AC power; a waveform of the AC power.

The invention relates to power supply systems. There is provided an apparatus and a method for supplying electric power to an electric device. In the method an indication of a desired power level to be supplied to the electric device is obtained. Electric power is received as DC power by a constant current regulator unit, which inverts the DC power to AC power and supplies the AC power to a reactance (T1) to be transformed to an output power. The output power is supplied from the reactance (T1) to the electric device. The method further comprises adjusting the AC power supplied to the reactance (T1) by using at least two of the following: voltage level of the AC power; the frequency of the AC power; a waveform of the AC power.

A power conversion device includes a case including an upper case and a lower case; an inverter that is accommodated in a first partial case and is fixed to the first partial case, the first partial case being one of the upper case and the lower case; and a capacitor that is connected to the inverter by a positive electrode bus bar and a negative electrode bus bar, the capacitor being disposed in an internal space of a second partial case that is another of the upper case and the lower case. The first partial case includes a fastening portion that extends from an internal space of the first partial case to the internal space of the second partial case. In the internal space of the second partial case, the capacitor is fastened to the fastening portion.