Reactive power compensation device of double-H-bridge modular multilevel converter (MMC) structure under three-phase unbalance and control method of reactive power compensation device

Abstract

The invention discloses a reactive power compensation device of a double-H-bridge modular multilevel converter (MMC) structure under three-phase unbalance and a control method of the reactive power compensation device, and relates to a reactive power compensation device of an MMC and a control method of the reactive power compensation device. The invention aims to solve the problems of poor energy mobility among three phases, low system working efficiency and poor safety and stability existing in the reactive power compensation device in the prior art when a three-phase power grid is at a voltage unbalance state. In the reactive power compensation device, a first controller of a master control part adopts a double-loop control strategy based on positive and negative sequence separation of feedforward decoupling to generate a three-phase modulation signal, a driving signal is generated by a voltage sequencing control method based on carrier phase shifting, and a second controller adopts the combination of a balance control strategy on capacitive voltage of a second H-bridge unit and a control strategy for suppressing system circulation to generate the three-phase modulation signal on the basis of positive and negative sequence separation on the circulation. By the reactive power compensation device, operation can be rapidly, safely and stably carried out under the condition of the unbalance of the power grid.

Description

technical field [0001] The invention relates to an MMC reactive power compensation device and a control method thereof, in particular to a reactive power compensation device with a double H-bridge MMC structure under three-phase unbalance and a control method thereof, and belongs to the technical field of reactive power compensation. Background technique [0002] Electric energy is an energy necessary for people's life, and its coverage and application degree represent the comprehensive national strength of our country. With the rapid development of power electronics technology, it has been widely used in the power field, and because of the increasing unbalanced and nonlinear loads in the distribution network, the power quality has been seriously affected, and its harm is becoming more and more serious. Seriously, it must be changed. Static var generator (STATCOM) is a compensation device based on fully controlled power electronic devices. It has the characteristics of smal...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of poor energy flow between the three phases, low system efficiency, poor safety and stability, etc.

Images