Method and system for power control of photovoltaic power generation in direct-current microgrids

Abstract

The invention relates to photovoltaic power generation technology for direct-current microgrids and aims to provide a method and a system for power control of photovoltaic power generation in direct-current microgrids. The system comprises a photovoltaic power generation power controller which comprises a droop control module, a photovoltaic power-voltage curve fitting module, a rated point power control module and a voltage-current inner loop control module, and all of the modules of the photovoltaic power generation power controller are connected electrically to form a closed circuit. The photovoltaic power-voltage curve fitting module is further electrically connected with the voltage-current inner loop control module to transmit a photovoltaic direct-current bus voltage reference value, and the voltage-current inner loop control module outputs a pulse width modulation signal. The system is in a uniform control structure integrating various functions and can operate in a grid connection or an island state; when the system is in the grid connection state, photovoltaic power generation can be in a maximum power tracking mode or a fixed power tracking mode; when the system is in the island state, photovoltaic power generation can be in the maximum power tracking mode or a droop control mode, and participation in secondary voltage regulation of the direct-current microgrids can be realized.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation in a DC microgrid, in particular to a photovoltaic power control system and method in a DC microgrid. Background technique [0002] At present, distributed power generation technology based on renewable energy has been widely valued and developed around the world, especially photovoltaic power generation technology. In order to take advantage of some of the complementary properties of distributed generation technologies, microgrids have been intensively studied as a way to effectively integrate and efficiently utilize renewable energy. At present, microgrids mainly exist in the form of AC microgrids, but DC microgrids have many advantages over AC microgrids, such as no need to consider frequency and phase issues, only need to control DC bus voltage, and fewer converters , The connection method is simpler and will be subject to a lot of research. Due to its output DC charact...

AI Technical Summary

Problems solved by technology

When the rated point power P o When the value is lower, the economics of photovoltaic power generation will become worse; when the rated point power P o When the value is higher, if the sunlight is reduced, the support ability of the PV to the grid frequency will be limited; therefore, this method does not solve the problem of the rated point power P o choice of

In addition, the photovoltaic control in the DC microgrid is mainly the maximum power tracking control at present, and there are not many studies on the constant power control and droop control. Method for Integrating Sub-Voltage Functions in One Control Architecture

These obviously do not fully tap the potential of photovoltaic power generation, which is not conducive to the efficient use and further development of photovoltaic power generation

Images