Droop Control Method for Voltage Source Inverter in Independent Microgrid with Photovoltaic Energy Storage

Abstract

The present invention provides a droop control method of a voltage source inverter for a photovoltaic energy storage independent microgrid. Each photovoltaic power generation unit is taken as an independent controlled voltage source with no need for communication signals between distributed generations so as to avoid the constraint of the physical connection and ensure the high reliability of the system. Through adoption of the adaptive droop control equation, a direct current side voltage PI regulator is introduced to control the direct current side capacitor voltage to be equal to the direct current side given reference voltage and regulate the active-frequency curve to move up or down so as to ensure the output powers of other photovoltaic power generation units are not influenced when the output power of one of the photovoltaic power generation units is changed, allow each photovoltaic power generation unit to output with the maximum power, improve the service life of the energy storage unit and provide auxiliary contribution for the frequency support of the system.

Description

technical field [0001] The present invention relates to the technical field of microgrids, and more specifically, to a droop control method for a voltage source inverter in a photovoltaic energy storage independent microgrid. Background technique [0002] Renewable energy has attracted more and more attention because of its clean, environmental protection and sustainable development characteristics. As an effective means of connecting distributed power sources (especially renewable energy) to the grid, microgrid has gradually become a research hotspot in the field of electrical engineering. Among these renewable energy sources, photovoltaic power generation (PV) has gradually become one of the main distributed power sources due to its decreasing installation cost year by year. However, the intermittent and uncertain power generation is not conducive to the large-scale integration of photovoltaic systems. In order to overcome the uncertainty of photovoltaic system power gen...

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Problems solved by technology

[0006] The present invention provides a droop control method for a voltage source inverter in a photovoltaic energy storage independent microgrid to solve the problem of the frequency and voltage of the existing photovoltaic energy storage independent microgrid master-slave control only relying on the energy storage unit to support the system And the technical problems that lead to the disadvantages of low system reliability and performance

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