Droop Control Method for DC Microgrid

Abstract

The invention discloses a direct-current microgrid droop control method and relates to droop control methods, for solving the problem existing in conventional droop control that micro-source output voltage is decreased linearly along with increase of output current, direct-current bus generates high voltage deviation, and power distribution precision is low. The direct-current microgrid droop control method includes the steps of 1, introducing information of all micro-source output current and important bus voltage through low-speed communication; 2, implementing a linkage mechanism of current limit and current signal sending pause, to be specific, detecting power sent by every micro-source, sending an instruction to cut off a communication output channel switch once detecting that some of the micro-sources is loaded fully to prevent the micro-source from sending its current signal outwards but to allow the same to receive current signal sent from the other micro-sources and continue to generate power compensation and voltage compensation; and sending an instruction to close the communication output channel switch once detecting that the micro-source is not in full load. The direct-current microgrid droop control method improves quality of system voltage and guarantees normal running of the microgrid system even when the micro-sources select unreasonable droop coefficient.

Description

technical field [0001] The invention relates to a droop control method, in particular to a droop control method of a DC microgrid. Background technique [0002] In recent years, with the rapid development of distributed power supply and the continuous maturity of power electronic technology, the composition of power supply and load in the power grid has changed significantly. Therefore, more and more researchers pay attention to the DC microgrid. [0003] The important goal of coordinated control in the DC microgrid system is to achieve a reasonable load distribution among distributed power sources. Currently, there are two types of load distribution methods: centralized and distributed. The latter is more redundant and economical, easy to plug and play. The most widely used distributed load distribution method for microgrids is droop control. [0004] Despite the many advantages of droop control, the influence of wiring resistance cannot be ignored in low-voltage DC sys...

AI Technical Summary

Problems solved by technology

[0004] Although droop control has many advantages, in low voltage DC systems, the influence of wiring resistance cannot be ignored

Therefore, when using conventional droop control, there are two problems that cannot be solved at the same time

First: the output voltage of the micro-source will decrease linearly with the increase of the output current. When the output current of the micro-source is very large or a large droop coefficient is selected, the DC bus will produce a large voltage deviation; second, due to the micro-source There is a connection resistance between the source and the DC bus, and the accuracy of power distribution will be greatly reduced

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