Island alternating-current microgrid secondary frequency control method based on linear active disturbance rejection

Abstract

The invention discloses an island alternating-current microgrid secondary frequency control method based on linear active disturbance rejection. With the purpose of reducing the frequency and realizing the stable operation of a microgrid, an island alternating-current micro-grid model containing wind, light, firewood and storage is established, the influence of demand response is considered, the linear active disturbance rejection technology is applied to load frequency control, a linear active disturbance rejection controller is designed, a linear expansion state observer is adopted to perform online real-time estimation on the expansion state, active compensation is performed on the estimated disturbance, and therefore the effects of rapidly eliminating the disturbance and keeping the frequency stable are achieved. The control method inherits the advantages of simplicity and convenience in debugging and easiness in use of a proportion-integral differential (PID) controller, has better control quality on a nonlinear, uncertain and strong-coupling system, and can achieve a better decoupling effect, so that the robustness and the adaptability of the system under an unknown strong-disturbance effect are enhanced.

Description

technical field [0001] The invention belongs to the technical field of frequency control of an island AC microgrid, and in particular relates to a secondary frequency control method for an island AC microgrid based on linear active disturbance rejection. Background technique [0002] With the development of the national economy, the demand for electricity is growing rapidly, and the scale of the power grid is also increasing. The disadvantages of the ultra-large-scale power system are becoming more and more prominent: high cost and difficult operation. In addition, due to the depletion of fossil energy and its high pollution to the ecological environment, energy represented by wind energy and solar energy has attracted widespread attention due to its clean and renewable characteristics. However, the access of distributed power makes the power flow between the power source and the user side change from one-way to two-way, which greatly increases the complexity and uncertainty...

AI Technical Summary

Problems solved by technology

Although energy storage devices can adjust quickly, they have capacity limitations

In addition, a controller that adaptively adjusts the droop coefficient can achieve no static error at the island frequency, but in a low-voltage microgrid with resistive lines, the droop control is difficult to achieve a satisfactory control effect

The time scale of frequency response based on renewable energy is too large to quickly stabilize the power fluctuation of a single microgrid

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