Grid-connected phase lock method for electrified railway power treatment and adjustment device

Abstract

The invention relates to a grid-connected phase lock method for an electrified railway power treatment and adjustment device. The method comprises the steps that (1) power grid voltage unbalanced deformation is carried out on the three-phase alternating current component of the power grid voltage; Clark transform is carried out on the deformed power grid voltage; and the power grid voltage is mapped to an alpha beta stationary coordinate system to acquire V alpha beta; (2) the components v alpha and v beta of V alpha beta on alpha and beta axes are shifted by 90 degrees through a second order generalized integrator SOGI module respectively, and the positive-sequence component is calculated; and (3) the extracted positive-sequence component is replaced by the power grid voltage, and the phase lock loop of single synchronization coordinate system software is used to realize the phase lock function of the power grid voltage. Compared with the prior art, the method provided by the invention can effectively filter out harmonic components in the power grid voltage and extract the basic positive sequence component therein to realize successful phase lock.

Description

technical field [0001] The invention relates to a grid-connected phase-locking method, in particular to a grid-connected phase-locked method of an electrified railway electric energy management adjustment device. Background technique [0002] The reliability and safety of power supply in the traction power supply network of electrified railways is an important guarantee for the safe, reliable and economical operation of electric locomotives. As a special electric load, the electric locomotive adopts a single-phase power supply mode, and it will inevitably inject negative sequence current into the upper power system when no compensation measures are taken; It brings power quality problems such as reactive power, harmonics, and voltage fluctuations, and seriously deteriorates the power quality of the traction power supply network and its superior power system, especially the imbalance and harmonic problems. [0003] In order to solve the unbalanced and harmonic problems of el...

AI Technical Summary

Problems solved by technology

As a special electric load, the electric locomotive adopts a single-phase power supply mode, and it will inevitably inject negative sequence current into the upper power system when no compensation measures are taken; It has brought power quality problems such as reactive power, harmonics, and voltage fluctuations, and seriously deteriorated the power quality of the traction power supply network and its upper-level power system, especially unbalance and harmonic problems.

[0003] In order to solve the unbalanced and harmonic problems of electrified railway traction transformers, the current trend is to use electrified railway power control devices (RPC), but this device must be able to effectively realize grid connection, and be able to adapt to the unbalanced load of electrified railways, Environment with high harmonic content

Due to the influence of the power grid environment, the traditional hardware phase-locking will have multiple grid-connected zero-crossing points, resulting in grid-connected failure

However, the software phase-locked loop under the single synchronous coordinate system is only suitable for the three-phase symmetrical power grid. Although the decoupled software phase-locked loop based on the double synchronous coordinate system can adapt to the unbalanced power grid, it is not suitable for the power grid environment with high harmonic content. , its phase-locking accuracy rate is very low, and it is also prone to failure of phase-locking grid connection

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