Aggregation equivalent method for large-scale photovoltaic power generation system based on structure preserving method

Abstract

The invention provides an aggregation equivalent method for a large-scale photovoltaic power generation system based on a structure preserving method. The method comprises the steps of establishing adetailed mathematical model of a two-stage photovoltaic power generation system, wherein the detailed mathematical model comprises a mathematical model of a photovoltaic array, an average model of a preceding-stage Boost circuit, an average model of a backward-stage grid-connected inverter, an equivalent model of a transformer, and mathematical models of a maximum power point tracking controller and a grid-connected voltage and current controller; according to an energy conservation relation among magnetic field energy, electric field energy and generalized potential energy existing in the photovoltaic power generation system, obtaining a relation between state variables the detailed model and an equivalent model of the large-scale photovoltaic power generation system; determining a current and voltage relation between the detailed model and the equivalent model according to the same active power output and power grid access mode between the detailed model and the equivalent model; andutilizing a capacity weighting method, comparing state equations among different models, and providing an equivalent parameter calculation method of an aggregation equivalent model. The method has the beneficial effects that the aggregation model is enabled to reserve the same circuit and control structure as the original photovoltaic power generation system on the basis of simplifying the reduced order model, and meanwhile, an accurate and reliable calculation method is provided for solving equivalent parameters of a photovoltaic array, a Boost circuit, an inverter, an output filter, a transformer, a maximum power point tracking controller and a grid-connected voltage and current controller in the aggregation equivalent model.

Description

technical field [0001] The invention belongs to the technical field of new energy grid-connected power generation, and in particular relates to a calculation method of an aggregation equivalent model and equivalent parameters of a large-scale photovoltaic power generation system based on a structure maintenance method. Background technique [0002] Due to the easy availability of photovoltaic resources and its low-cost and non-polluting characteristics, photovoltaic power generation is considered an important way to promote energy transformation and meet environmental challenges. In general, in order to meet the output of sufficient active power, the actual photovoltaic power station uses multiple photovoltaic inverters to connect to the distribution network in parallel cluster mode, so the photovoltaic power station is a large-scale high-order system. The simulation analysis of large-scale photovoltaic systems will take a long time and occupy a large computing space. In ad...

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Problems solved by technology

Patent CN109638892A uses a fuzzy clustering algorithm to obtain the equivalent model of a photovoltaic power station, standardizes the clustering index of photovoltaic power generation units, initializes the membership matrix, and obtains the equivalent aggregation parameters of the photovoltaic power station according to the clustering results. Considering the calculation method of the equivalent parameters of the AC side filter inductor, filter capacitor and DC side filter capacitor of the photovoltaic inverter, but still not including the photovoltaic array, transformer, maximum power point tracking controller, inverter controller, etc. Calculation of equivalent parameters of

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