Adaptive-droop-control-based wind-photovoltaic-energy-storage micro-grid frequency modulation method

Abstract

The invention discloses an adaptive-droop-control-based wind-photovoltaic-energy-storage micro-grid frequency modulation method. The method comprises the following steps that: modeling is carried out on a wind turbine and a doubly-fed generator and a model of a wind generating set is constructed; data fitting is carried out on a short-circuit current, an open-circuit voltage, and a maximum operating point voltage and current to determine a model of a photovoltaic power generation system; a relation between a storage battery charge state and a discharging depth, a current and an electrolyte temperature inside the storage battery is described and a third-order model of an energy storage unit is constructed; a droop control strategy that the outermost layer is used for droop controlling of a frequency voltage, the inner layer is used for power controlling, and the innermost layer is used for current controlling is used for controlling distributed power supplies; and droop coefficients of the wing generating set, the photovoltaic power generation system, and the energy storage unit are adjusted by using an adaptive control method and optimal power distribution in a state of steady-state operation and in a state of disturbance is carried out. With the method, the number of times of charging and discharging of the battery energy storage is effectively reduced and the pressure is adjusted.

Description

technical field [0001] The invention relates to a frequency modulation method for a wind-solar-storage micro-grid based on adaptive droop control. Background technique [0002] With the development of renewable energy such as wind power and photovoltaics, the penetration rate of renewable energy power generation has increased rapidly, and its impact on power grid operation has gradually increased. As an important grid-connected method of renewable energy, the micro-grid can effectively organize a variety of distributed power sources, loads, and energy storage. It has two typical operating modes: under normal circumstances, it is connected to the conventional distribution network The operation is called interconnection mode; when a grid fault is detected or the power quality does not meet the requirements, the microgrid will be disconnected from the grid and run independently, which is called island mode. Compared with the main network, the scale of a single microgrid is sma...

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Problems solved by technology

[0004] However, none of the above studies considered the influence of the power margin of the micro-grid network on the effect of frequency modulation control, and failed to give full play to the characteristics of fast response of photovoltaics and the power support capability of each micro-source.

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