Back-to-back converter for high-voltage alternating current drive

Abstract

The invention relates to a modularized multilevel back-to-back converter used for a high-voltage alternating current (AC) drive system. The back-to-back converter comprises a plurality of bridge arms with the same structure, wherein each bridge arm comprises low-voltage power units and an induction module which are in serial connection; the structures of the low-voltage power units are the same, each bridge arm corresponds to single input or output phase of the converter; the upper ends of the bridge arms are connected, the lower ends of the bridge arms are connected; the high-voltage direct current (DC) bus does not need to support capacitors; the induction module comprises two serial capacitors; two terminals of the two capacitors are connected, the connection point is used as the output terminal of the bridge arm; and one of the residual two terminals of the two capacitors is connected with the lower end of the upper bridge arm of the bridge arm, and the other terminal is connected with the upper end of the lower bridge arm of the bridge arm. Each low-voltage power unit adopts two electronic power switch elements to realize three-level voltage output; and dead time is not needed to set for the on / off of the switch elements.

Description

technical field The invention relates to a back-to-back converter, in particular to a multi-level back-to-back converter capable of realizing energy bidirectional flow and control in a high-voltage AC drive system. Background technique With the development of power electronics and AC drive technology, high-voltage AC drive systems, such as high-voltage frequency conversion speed control systems, as one of the main means of energy saving and emission reduction, have been more and more widely used in various fields of the national economy. In the practical application of high-voltage AC drive system, in many occasions, the energy of the motor needs to be fed back to the grid side when braking, so as to save energy. Therefore, the back-to-back converter with energy bidirectional flow and control capabilities has also been widely used. . However, at the current level of power electronics technology development, a single and single power electronic switching device generally ca...

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