Method for additional function control for modularized multilevel current converter

Abstract

The invention discloses a method for additional function control for a modularized multilevel current converter. The method comprises the steps that alternating voltages and alternating currents at the load side are collected; based on the instantaneous power theory, a harmonic current instantaneous value at the load side is calculated; a harmonic current instantaneous calculation value is adjusted by a closed loop so that an additional control voltage order can be obtained; the additional control voltage order and the power control voltage order are added together to serve as a voltage control order of the modularized multilevel current converter; alternating voltages and alternating currents at the load side are collected again. Under the condition that a filter device is not additionally arranged, harmonic pollution, caused by a harmonic source, of a connected alternating current system is effectively reduced, the power grid power quality is improved, and the stability and the quality of the system are improved.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to the control technology of a modular multilevel converter. Background technique [0002] With the development of society, the existing grid structure can no longer meet the needs of economic growth, and there is an urgent need to upgrade the existing AC grid. Flexible DC transmission will play an increasingly important role in the interconnection of regional grids and the power transmission of city center loads due to its independent adjustment of active and reactive power, passive power supply capabilities, and easy construction of DC grids. In addition, flexible direct current transmission adopts buried direct current cables, without alternating electromagnetic fields and oil pollution, and can complete the expansion and transformation of urban power grids without electromagnetic interference and without affecting the city's appearance, so as to meet the ne...

AI Technical Summary

Problems solved by technology

[0003] When harmonic source loads such as rolling mills are powered by AC and modular multi-level flexible DC transmission dual power supplies, the harmonics generated by itself will not only cause harmonic pollution to the AC system, but also affect the modular multi-level converter. safe and stable operation of the

If a filter is installed, additional investment will be added, and the economy is poor

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