Simplified multi-level converter space vector modulation method

Abstract

The invention discloses a simplified multi-level converter space vector modulation method, and relates to the field of space vector modulation methods of multilevel converters, and is used solve problems that the redundant switch state is greatly increased along with the increase of the level number in the traditional SVM technology, and the SVM is difficult to realize due to the calculation of the redundant switch state and the selection of a proper switch state. The method comprises following steps: step 1: a vector expression is established; step 2: a reference vector track model is established; step 3: reference signals and level signals are respectively represented by coordinate components and corresponding component sum of reference vector and basic vector; step 4: a star-shaped connection multi-level converter is constructed; step 5: the sampling of the phase voltage reference vector track model of the star-shaped connection multi-level converter can be carried out, and the reference vector is acquired after synthesizing; step 6: equivalent base vector action time is calculated; step 7: the components of the equivalent basic vector of the star-shaped connection multilevel converter and the component sum are used as the switch state used for controlling the triangle-shaped connection multilevel converter line voltage.

Description

technical field [0001] The invention relates to the field of space vector modulation methods for multilevel converters, in particular to a simplified space vector modulation method for multilevel converters. Background technique [0002] Current large-capacity multi-level converters mostly use Carrier Phase Shifted Modulation (CPS) and Nearest Level Modulation (NLM). With the increase of the number of cascaded sub-modules, the carrier phase-shift modulation technology requires higher carrier synchronization, which requires a large number of hardware resources and strict logic timing. Therefore, the number of levels of the multilevel converter using CPS is not high, which limits the improvement of the voltage level of the converter. In the recent level modulation technology, when the level number is small, the voltage tracking error is large, and in the frequency spectrum of the output voltage, a large number of harmonic components are widely distributed in a wide frequency ...

AI Technical Summary

Problems solved by technology

[0003] The SVM strategy is widely used in three-level and five-level converters, but it is not common in industrial applications of high-voltage and large-capacity converters. The reason is that SVM technology requires 2 / 3 conversion with the increase of the number of levels, redundant The switch state vector is greatly increased, and the calculation of the redundant switch state vector and the selection of the appropriate switch state lead to a great increase in the difficulty of the SVM algorithm; therefore, the market urgently needs to develop a simplified multi-level converter space vector modulation method to help people solve existing problems

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