Robust autonomous control method for bus voltage of DC micro grid

Abstract

The invention relates to a robust autonomous control method for the bus voltage of the DC micro grid. A nonlinear interference observer, DC bus voltage sagging control and voltage / current double-loop control are combined in the method. The method comprises that a DC-DC current transformer model is established; the nonlinear interference observer is used to track output current of the DC-DC current transformer model, and a band pass filtering link based on a second-order general integration link is used to filter output results of the observer; in DC bus voltage sagging control, the output results of the nonlinear interference observer serve as the output current; and in voltage / current double-loop control, perturbation current of the output results of the nonlinear interference observer is used for feedforward control. The method can be used to realize peer-to-peer control and autonomous operation of the DC micro grid, effectively improves dynamic response of the control system, inhibits fluctuation and impact of transient DC bus voltage, and is conducive to expansion and plug-and-play of distributed power supplies and loads in the DC micro grid.

Description

technical field [0001] The invention belongs to the technical field of microgrid converter control, and relates to a robust autonomous control algorithm for DC microgrid bus voltage based on a nonlinear disturbance observer. Background technique [0002] The proposal of micro-grid technology aims to realize the flexible and efficient application of distributed power sources, solve the problem of grid-connected operation of a large number of distributed power sources in various forms, and help to continuously supply power to important loads when the power grid catastrophe occurs, avoiding the direct failure of intermittent power sources. Affecting the power quality of local users has important economic significance and social value. Compared with AC microgrids, DC microgrids can more efficiently and reliably accommodate distributed renewable energy generation systems such as wind and light, energy storage units, electric vehicles and other DC power loads, and have become one ...

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Problems solved by technology

Literature [5] established a large-signal model of a DC microgrid operating independently, which provided a stability criterion for system parameter design, but the influence of the control system on the equivalent model was ignored in the paper

Literature [6] proposes a distributed oscillation suppression strategy for the problem that the LC filter is likely to cause resonance in the DC microgrid. However, the interaction between multiple damping controllers will increase the complexity of parameter design.

[0004] The above literatures mainly focus on the stability of the DC microgrid, but there are few studies on how to improve the dynamic response of the DC bus voltage control system

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