Control System of Multi-function Grid-connected Inverter for Distributed Power Grid Based on Intelligent Optimization Algorithm

Nowadays, the global energy crisis and environmental pollution are becoming more and more serious. Making full use of clean and renewable energy such as photovoltaic and wind power is the inevitable trend of power grid development in the future. Microgrid, as an effective means of distributed power access to the power grid, has gradually attracted widespread attention. In the distributed power generation system, various renewable energy sources are generally connected to the medium and low voltage distribution network through inverters. There are various power quality problems in point of common coupling (PCC) due to the extensive use of nonlinear power electronic devices in modern distribution system and the small capacity and various types of loads of the distribution network connected with renewable energy. To solve the above problems, this paper first establishes the structure of the distributed inverter system and the mathematical model of the distributed inverter system under balanced and unbalanced conditions. The advantages and disadvantages of traditional control methods for distributed inverter systems are introduced, and a control method for multiple distributed inverter systems based on adaptive virtual impedance is proposed. The experimental analysis results show that the improved repetitive controller can achieve fast and accurate tracking of the reference current, and the multi-function grid-connected inverter based on the improved repetitive control algorithm has excellent power quality control ability.