Parallel side compensation optimal-allocation control device and method for MMC (modular multilevel converter (MMC) type UPQC (unified power quality conditioner)

Abstract

The invention belongs to the technical fields of medium-voltage flexible alternating current power transmission and distribution and power electronic control of power systems, and particularly relates to a parallel side compensation optimal-allocation control device and a parallel side compensation optimal-allocation control method for an MMC (modular multilevel converter) type UPQC (unified power quality conditioner). The device consists of a parallel side converter of the MMC type UPQC and a parallel side compensation optimal-allocation control system, which are connected with each other. The parallel side compensation optimal-allocation control device and the parallel side compensation optimal-allocation control method for the MMC type UPQC aim to avoid the phenomenon that the parallel side converter of the MMC type UPQC runs under an overload condition due to the fact of harmonics, reactive power and unbalanced current, simultaneously and possibly caused by the use of a great number of various flexible power electronic components and nonlinear loads, of a medium-voltage feeder line load side user in a conventional power system; the compensation optimal-allocation control method is simple and reliable in design and explicit in physical concept, and the application range of the MMC type UPQC is greatly widened.

Description

technical field [0001] The invention belongs to the technical field of medium-voltage flexible AC power transmission and distribution and power electronic control in power systems, and in particular relates to an MMC-type UPQC parallel-side compensation optimization distribution control device and method. Background technique [0002] With the widespread application of general loads (such as three-phase full-bridge rectifier circuits, electric arc furnaces, etc.) containing a large number of power electronic devices and various nonlinear components in power systems, the problem of power environmental pollution has become increasingly serious. , unbalance, reactive current quality problems and voltage sag, harmonic voltage and other voltage quality problems appear at the same time, and there is an urgent need for a device that can provide comprehensive treatment. Among many power quality control devices, Unified Power Quality Conditioner (UPQC) integrates the functions of Act...

AI Technical Summary

Problems solved by technology

[0005] The present invention aims at the fact that the harmonics, reactive power and unbalanced compensation current caused by the increase of power users on the load side exceed the maximum output current of the converter on the parallel side of the device, and the output of the converter on the parallel side of the UPQC is so unreasonable that it cannot Efficiently exploit the shortcomings of the current quality problem management function of the UPQC parallel side converter, and propose a MMC type UPQC parallel side compensation amount optimization distribution control device and method

Images