Sub module capacitance and voltage balancing and optimizing method for modularized multi-level converter

Abstract

The invention relates to a sub module capacitance and voltage balancing and optimizing method for a modularized multi-level converter. The system used in the method is a modularized multi-level conversion system, and a flexible direct current power transmission system valve base control system framework taking a distributed parallel processing mode as a framework is established. The method comprises the following steps of (1) determining a control target of the balancing control for the sub module capacitance and voltage; (2) establishing a sub module state decision optimizing model; (3) performing balancing and equalizing on the sub module capacitance and voltage; (4) verifying the balancing and equalizing on the sub module capacitance and voltage. The distributed computation framework is adopted, the processing capability is greatly improved, and the aim of the application of a complex algorithm and a complex strategy in a high-voltage large-capacity flexible direct current power transmission system is ensured.

Description

technical field [0001] The invention relates to a balance optimization algorithm in the field of power electronic direct current transmission of a power system, in particular to a sub-module capacitor voltage balance optimization method of a modular multilevel converter. Background technique [0002] When the modular multilevel (MMC) technology is applied in the field of HVDC transmission, hundreds or even thousands of sub-modules need to be connected in series for the converter valve, and each sub-module must be controlled separately; the energy storage capacitors of the sub-modules are independent of each other, due to Due to the limitation of the manufacturing level, the capacitance, equivalent series internal resistance, self-discharge rate and temperature distribution all have a certain degree of discreteness. In addition, taking into account the energy pulsation, power pulsation and loss in the bridge arm, the charging During discharge, energy exchange and operation, t...

AI Technical Summary

Problems solved by technology

[0004] Tabu (Tabu Search) algorithm is an intelligent heuristic search optimization algorithm with flexible memory function. It avoids repeated searches by introducing a flexible storage structure and corresponding tabu criteria, and pardons some good states in the tabu table through the amnesty criterion. This ensures that the algorithm can search for the global optimal solution of the multi-extreme point objective function; the tabu search algorithm has been deeply researched and developed in many fields such as power system unit load distribution, distribution network fault restoration and reconstruction, and reactive power optimization. However, there are few researches and applications at home and abroad on the valve base control strategy of HVDC flexible DC transmission system based on the tabu search optimization algorithm.

Images