Alstom Technology Limited

General Electric Technology Gmbh

Thiago Batista Soeiro

Per Ranstad

Jörgen Linner

Johann Kolar

Jürgen Biela

A Voltage Source Converter (VSC) () with Neutral-Point-Clamped (NPC) topology with one or more phases, comprises an intermediate DC circuit having at least a first and a second capacitance connected in series between a positive terminal and a negative terminal, providing a central tap terminal between both capacitances, and at least one sub-circuit for generating one phase of an alternating voltage, each sub-circuit comprising an AC terminal for supplying a pulsed voltage; a circuit arrangement of the form of a conventional NPC converter, with a first series connection of at least two switches between said AC terminal and said positive terminal, a second series connection of at least two switches between said AC terminal said negative terminal, and switchable connections from said central tap terminal to the centers of both two-switch series connections; and additional first and second auxiliary switches assigned to said two-switch series connections.

Voltage source converter (VSC) with neutral-point-clamped (NPC) topology and method for operating such voltage source converter

Disclosed is a method for the improvement of the line quality in a system, in which a common feeding (), via at least one distribution transformer (), feeds at least two non-linear loads () drawing non-sinusoidal currents from the common feeding (), wherein between the common feeding () and the distribution transformer () there is at least one primary side transformer line () and between the at least one distribution transformer () and the loads () there is at least one lower voltage secondary side transformer line (), wherein at least one active filter () attached to at least one lower voltage secondary side transformer line () is used for the attenuation or elimination of higher order harmonics experienced by the common feeding (). Furthermore a high power distribution system for use of such a method is disclosed, in particular for the operation of an electrostatic precipitator.

Method to minimize input current harmonics of power systems such as ESP power systems

The disclosure relates to a method for the scheduling and/or the operation of a system of at least two power supplies () providing DC pulses to a consumer (), typically an electrostatic precipitator, wherein the power supplies () are energized by a common feeding (). According to the proposed method one power supply () is defined to be the reference power supply, and the initial pulses of each further power supply () are shifted by controlled delays (&#x3b4;) with respect to the pulses of the reference power supply so as to fill the gaps between the pulses of the reference power supply by the pulses of the further power supplies ().

Method for the operation of electrostatic precipitators

A method is provided for determining a control scheme for a voltage source converter (VSC) with a topology of three bridge legs between each of three phases of a grid and a neutral point. The method includes: analyzing the waveform of the grid and/or a load voltage and determining an allowed period for no-swilching of the corresponding bridge leg; operating the VSC with different clamping carrier modulator frequencies, and then analyzing the balance in the operating junction temperatures and/or power losses across the active switches and also analyzing the total losses of the VSC; comparing the balance and the total losses of different clamping carrier modulator frequencies and selecting the clamping carrier modulator frequency; operating the VSC with the selected clamping carrier modulator frequency, and optimizing the balance in the operating junction temperatures and/or power losses across the active switches and the total losses of the VSC.

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Zurich, Switzerland

Thiago Batista Soeiro