Method for controlling an converter that is connected to a direct-current source

Abstract

A method for controlling a static converter connected to a direct-current source. The converter has power conductor switches that can be deactivated and is configured to supply a distribution network with three-phase voltage. The currents flowing through the respective power semiconductor switches are measured, current values respectively assigned to the power semiconductor switches are obtained, the current values are sampled and digitized to obtain digital current values. The latter are checked by a logic in a control unit for the presence of an excess current condition. If no excess current condition is detected, the power semiconductor switches are activated and deactivated with the aid of a nominal operation controller and if an excess current condition is detected, at least the power semiconductor switches with assigned digital current values that fulfill the excess current condition are deactivated after a pulse block has expired. For the digital current values that fulfill the excess current condition, all power semiconductor switches, which are connected to the positive direct-current terminal, are activated and all power semiconductor switches, which are connected to the negative direct-current terminal are deactivated or vice versa. For the digital current values that do not fulfill the excess current condition, the power semiconductor switches are controlled once again by the nominal operation controller.

Description

technical field [0001] The invention relates to a method for regulating a converter connected to a DC voltage source, the converter having disconnectable power semiconductor switches which are designed to provide a three-phase voltage for a distribution network. Background technique [0002] A method for regulating a DC voltage converter is known, for example, from High Voltage Direct Current Transmission. HVDC transmission is used on the one hand to transmit electrical energy over long distances. Another application involves, for example, the coupling of grids with different three-phase voltage frequencies. For HVDC transmission, the two converters are connected to each other via a DC link or a DC link. The converters are each connected to a three-phase voltage grid and essentially consist of power semiconductor switches. Self-guiding (selbstgefuehrt) converters, ie converters with self-guiding power semiconductor switches, are increasingly used in grid coupling. This a...

AI Technical Summary

Problems solved by technology

[0013] The invention solves the above-mentioned technical problem by means of a method for regulating a converter connected to a DC voltage source, the converter having a disconnectable Power semiconductor switches, wherein the current flowing through each power semiconductor switch is measured under the condition of obtaining the current values ​​respectively corresponding to these power semiconductor switches, the current value is sampled, and the sampled current value is digitized to obtain digital current value and is checked by a logic implemented in the regulation unit for the occurrence of an overcurrent condition, wherein, in the event of an overcurrent condition not being met, switching on and off is regulated by means of rated operation The power semiconductor switch, and in the case of an overcurrent condition, at least disconnects the power semiconductor switch loaded with a digital current value satisfying the overcurrent condition, after a pulse blocking duration expires and after the overcurrent condition is satisfied Under the condition of the digital current value, turn on all the power semiconductor switches connected to the positive DC terminal and disconnect all the power semiconductor switches connected to the negative DC terminal, or vice versa. Under the condition, the regulation of the power semiconductor switch is realized again through the regulation of the rated operation

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