Method for increasing and controlling power generation capacity of cascaded boosting grid-connected system of photovoltaic direct-current converters

Abstract

The invention relates to a method for increasing and controlling the power generation capacity of a cascaded boosting grid-connected system of photovoltaic direct-current converters. Each photovoltaicdirect-current converter adopts a modular cascade structure with inputs connected in parallel and outputs connected in series. Each photovoltaic DC converter determines the upper limit range and thelower limit range of its output voltage according to the number of real-time operation modules and the number of available redundant modules, the output voltage of the DC converter is detected in realtime, the number of modules in the DC converter to be switched on or switched off are determined, and each photovoltaic DC converter is enabled to work in a maximum power tracking mode as much as possible; and when the switching control of the photovoltaic DC converter module still cannot allow the photovoltaic DC converter module to maintain the maximum power tracking in operation, the DC converter realizes free switching between the maximum power tracking mode and a voltage-limiting working mode, and enters the voltage-limiting working mode. According to the invention, the problems of out-of-limit output voltage and power loss of the photovoltaic direct-current converters caused by power mismatch of each photovoltaic direct-current converter are solved, and the power generation capacityof the cascaded boosting grid-connected system of the photovoltaic direct-current converters can be effectively improved.

Description

technical field [0001] The invention relates to a control method for increasing the power generation of a photovoltaic DC converter series boost grid-connected system, which is applied to a photovoltaic DC converter series boost grid-connected system in a large-scale photovoltaic power station. Background technique [0002] Photovoltaic power generation bases can gather superior resources, exert scale effect, and greatly reduce power generation costs, which is an important direction for the large-scale development and application of photovoltaic power generation in the world. However, the low-voltage AC collection method is used inside the traditional mega-kilowatt photovoltaic power generation base power station. There are many confluence lines, long distances, large line losses, and a lot of equipment required, which directly affects the overall efficiency and cost of the photovoltaic power station. At the same time, the AC collection system The capacitive and inductive re...

AI Technical Summary

Problems solved by technology

[0004] The technical problem of the present invention is to overcome the deficiencies of the prior art, and provide a photovoltaic DC converter series step-up grid-connected system power generation increase control method, which mainly solves the converter output voltage caused by the power mismatch of each photovoltaic DC converter Over-limit problems and power loss problems, make each photovoltaic DC converter work in the maximum power tracking mode as much as possible, so as to increase the power generation of the system; provide technical support for the demonstration application and promotion of the photovoltaic DC converter series boost grid-connected system, It has important theoretical research significance and engineering practical value

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