Modulating method and control device of soft direct current power transmission modularized multi-level transverter

Abstract

The invention discloses a modulating method and a control device of a soft direct current power transmission modularized multi-level transverter. The method comprises the steps of controlling the power as well as voltage and current in a closed-loop mode to obtain three-phase modulation waves; and according to the three-phase modulation wave or the modulation wave and the sub-module number, issued by a direct current control protective system, and the sub-module number put into each bridge arm and the interpolation increment of the putting number of each bridge arm sub-module, obtained by calculating the rated voltage of the sub-modules, overlapping a high-frequency interpolation increment on the sub-module number put on the low-frequency bridge arm by a high-frequency FPGA (field programmable gate array), thus obtaining the high-frequency bridge arm modulation command and realizing the high-level number output. The modulating method and the control device of the soft direct current power transmission modularized multi-level transverter can meet the modulation demands of the soft direct current power transmission modularized multi-level transverter, and can save software and hardware resources, and break through the limitations such as long control period, low frequency and low output level number of traditional digital controllers such as a DSP (digital signal processor), thus realizing the high-level number or even whole-level output under the low-frequency control, obviously reducing the output voltage harmonic waves and improving output electric energy quality.

Description

technical field [0001] The invention belongs to the technical field of flexible power transmission and distribution in power systems, power electronics and user power, and in particular relates to a modulation method and a control device for a modular multilevel converter of flexible DC power transmission. Background technique [0002] With the development of fully-controlled power electronic devices and the application of power electronics technology in power systems, the technology of flexible direct current transmission (VSC-HVDC) based on voltage source converters has attracted increasing attention. Modular Multilevel Converter (Modular Multilevel Converter) is a kind of voltage source converter used in VSC-HVDC system. It is composed of multiple half-bridge or full-bridge sub-modules connected in a certain way. By separately controlling the input and disconnection states of the IGBT components of each sub-module, the AC voltage output by the converter is close to a sine...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a modulation method of a flexible direct current transmission modular multilevel converter, and to provide a control device using the modulation method to solve the problem of low output levels of the existing modulation method

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