A DC Microgrid Power and Voltage Regulation Method Considering Line Impedance and Local Load

Abstract

The present invention relates to a DC micro-grid power and voltage regulation method considering line impedance and local load. The method is used in the island operation mode of the DC micro-grid. The DC micro-grid contains multiple sets of DGs and different types of loads, each The DGs are connected in parallel to the common DC bus through the corresponding converters. This method uses an improved droop control strategy to make each DG distribute load power according to its rated capacity, eliminate the influence of line impedance and local load on power distribution, and maintain the bus voltage. Stablize. Compared with the prior art, the power distribution control and voltage recovery control strategy of the island DC microgrid proposed by the present invention can effectively improve the load power distribution accuracy among parallel multiple distributed power sources in the island DC microgrid, and improve the efficiency of distributed power sources. Efficiency, give full play to the "plug and play" feature of DG. At the same time, maintaining the DC bus voltage enables the microgrid system to operate stably.

Description

technical field [0001] The invention relates to a coordinated output power control and bus voltage stabilization of a DC microgrid connected in parallel to a common DC bus, in particular to a DC microgrid power and voltage regulation method considering line impedance and local load. Background technique [0002] Considering the current environmental pollution and the shortage of fossil fuels, distributed power generation technology based on renewable energy sources (RES) has been proposed and widely used. Connecting distributed generation (DG) to the distribution network in the form of a microgrid is generally considered to be one of the effective ways to utilize distributed generation. Traditionally, microgrids are divided into DC microgrids and AC microgrids according to the type of access bus. Compared with the AC microgrid, the DC microgrid has no problems such as phase and reactive power, which makes the voltage distribution independent of the inductance and capacitanc...

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Problems solved by technology

The literature "Yang Jie, Jin Xinmin, Wu Xuezhi, et al. An improved current load distribution control strategy for DC microgrid [J]. Chinese Journal of Electrical Engineering, 2016, 36(1): 59-67" proposed a A droop control strategy that uses the voltage change rate instead of the voltage to realize the precise distribution of the load current, but there is still a large deviation in the bus voltage

The literature "Jiang Weiming, Zhao Jinbin, Gao Mingming, et al. Research on the control strategy of independent DC microgrid with voltage self-recovery characteristics [J]. Grid Technology, 2019.1315: 1-9" obtains line impedance information through the method of single pulse injection, and It is introduced into the droop coefficient in the form of negative compensation to suppress the adverse effects of line impedance inconsistency on current distribution, but this strategy has high requirements for the selection of measurement interval time after pulse injection

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