Direct-current micro-grid flexible virtual inertia control method based on energy storage converter

Abstract

A direct current micro-grid flexible virtual inertia control method based on an energy storage converter comprises the steps that firstly, a direct current micro-grid small-signal physical model containing a plurality of constant power loads is established, and a system state space equation is obtained based on the direct current micro-grid small-signal physical model; secondly, the transfer function of the DC micro-grid system realizes the double closed-loop control of the energy storage converter, and corrects the flexible virtual inertia according to the power limit of the system and the stable condition of the bus voltage. Thirdly, drawing a system Bode diagram according to the transfer function of the direct-current micro-grid system, and judging whether the system is stable or not; and finally, analyzing an output characteristic curve of the physical model of the direct-current micro-grid system, introducing a noise link, and researching system output power characteristics under the random disturbance load. The application of the flexible virtual inertia control method enables the system voltage fluctuation to be more moderate; by monitoring the vibration condition of the bus voltage of the system and introducing a voltage differential link into the controller, the inertia of the system is adjusted in real time, the response speed and stability of the system are improved, and the overshoot during stabilization is reduced.

Description

technical field [0001] The invention belongs to the field of DC microgrid energy storage link control, and relates to a DC microgrid flexible virtual inertia control method based on bus voltage stability. Background technique [0002] With the development of the global economy, people's consumption of fossil fuels such as coal and oil is increasing, which not only causes a shortage of resources, but also brings more and more attention to environmental pollution. In order to solve the problems of energy shortage and ecological environment protection, the development and utilization of distributed energy mainly based on new energy will play an important role. Micro-sources such as photovoltaic arrays, fan equipment, and energy storage devices are generally connected to DC micro-grids through power electronic devices, resulting in the system having significant power electronic characteristics. DC microgrids are generally connected to various high-penetration renewable energy s...

AI Technical Summary

Problems solved by technology

When the load increases or decreases, distributed energy fluctuates or even introduces constant power loads, the bus voltage of the DC microgrid is easily unstable, which poses a threat to system stability

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