Control system and control method for photovoltaic auxiliary grid-connected power generation

Abstract

The invention provides a control system and a control method for photovoltaic auxiliary grid-connected power generation. The system comprises a direct current voltage boosting module, a direct current limited power voltage transformation module, a grid-connected inverter, a direct current compensation module, an alternating current inverse module, an alternating current switching module, a monitoring module and a control module. The method comprises the following steps that a photovoltaic module is opened to perform power generation; whether a public supply network loses power is judged, if the public supply network loses power, the photovoltaic module is used for independently supplying power to a user load; if the public supply network does not lose power, and the generated energy of the photovoltaic module is larger than that of the user load, the photovoltaic module is used for independently supplying power to the user load, at the same time, surplus electric energy is input into the public supply network in a grid-connected way; and if the generated energy of the photovoltaic module is smaller than that of the user load, the public supply network performs direct current compensation to electric energy output by the photovoltaic module. By adopting the control system and the method, the energy use efficiency is high during photovoltaic power generation, and the system is stably operated.

Description

technical field [0001] The invention belongs to the field of photovoltaic grid-connected power generation, and specifically relates to a control system and control method for photovoltaic auxiliary grid-connected power generation, and a power generation system using the control device and control method. Background technique [0002] Solar photovoltaic power generation systems can be divided into two types: centralized large-scale grid-connected photovoltaic power generation systems and decentralized small-scale grid-connected photovoltaic power generation systems. The main feature of the former is that the power generated can be directly transmitted to the power grid, and the power grid will be deployed uniformly to supply power to users. The latter, especially the residential rooftop photovoltaic power generation system combined with buildings, distributes the electricity generated by photovoltaic modules directly to the electricity loads of residential users, and the exce...

AI Technical Summary

Problems solved by technology

But this does not solve the following problem: when the power grid loses power for some reason, the grid-connected inverter will stop working due to the protection "island effect", resulting in energy waste

However, the use of charging devices and batteries greatly increases the investment in system construction and maintenance.

Images