In the new century, with the continuous progress of society and technology, the demand for energy among world powers has become increasingly strong, leading to various wars. Energy is the foundation and driving force for a country’s development, and the excessive exploitation and plundering of fossil energy have caused serious environmental problems, such as global warming, thinning of the ozone layer, and irreversible pollution. Therefore, modern society has higher requirements for the reliability, cleanliness, and safety of power supply, and the improvement and upgrading of the global energy structure is essential for the coordinated development of various regions. At present, clean energy such as hydropower, wind power, and photovoltaic power generation to replace traditional thermal power generation is the mainstream trend. As early as the end of the last century, the European Union issued the “White Paper on Renewable Energy” to reduce the proportion of non-renewable energy in the total energy. China, as the world’s largest developing country and the second-largest economy, has been gradually increasing its energy demand. With the deepening of domestic industrial development, the proportion of renewable energy power generation has gradually increased, especially wind power and photovoltaic power generation, which are expected to account for 78% of renewable energy in the future. Therefore, the integration of distributed energy into the main grid in the form of a microgrid will become the mainstream development direction.
The distributed access of new energy to the grid is conducive to local decentralized utilization and improving the reliability of user power supply. With the active development and large-scale access of distributed photovoltaic power on the user side, the construction of a flexible operation mode, responsive to user-side power management needs, and high energy quality is an effective way to achieve local consumption and utilization of new energy and give full play to the efficiency of distributed power generation systems. With the advancement of the national new energy policy, the construction of a smart grid, and the reform of the power market, the construction and application of microgrids have become increasingly important.
Compared with traditional centralized power generation, distributed power generation mainly adopts renewable energy sources, such as photovoltaic and wind power, which is environmentally friendly and clean with little pollution. The equipment for distributed power generation is installed dispersedly, with low investment, short construction period, and low power loss, which is highly efficient. When the large grid fails, distributed power generation can operate in an isolated island mode, which is reliable. With the advantages described above, distributed power generation has developed rapidly.
However, the energy supply in the current changing energy supply options has led to problems such as the variety of energy sources in the system, the increased risk of instability in operation, and the fluctuations caused by the large-scale access of distributed photovoltaic power, resulting in increased control risks in the operation of the power grid, uncoordinated energy balance between the supply and demand sides, multi-subject interest competition, and the coordination between power generation and energy storage has become the most prominent contradiction, especially in the eastern region where photovoltaic development is relatively rapid. Therefore, it is particularly important to establish an appropriate independent optical storage integrated microgrid model and formulate a reasonable energy management strategy for it.
The research status of microgrids is as follows:
| Aspect | Details |
|---|---|
| Microgrid Research Status at Home and Abroad | Microgrid is a local autonomous system, usually composed of loads, distributed power sources, energy storage devices, power electronic components, and an energy management system. It has more advanced strategies in energy management and more diversified energy structures and operation modes compared to the traditional grid, giving it comprehensive advantages. The main operation modes of microgrids include grid-connected and island modes. Countries such as the United States, Japan, and the European Union have made significant progress in microgrid research, and China is also actively developing its own microgrid technology. |
| Source-Side Energy Storage Research Status | The energy supply of distributed power generation in microgrids faces two prominent problems: energy discontinuity and volatility. Therefore, energy management and reasonable allocation are required when a large number of distributed power sources are integrated into the grid, which is also a major challenge in the current development of microgrid energy management. Many scholars have conducted in-depth research on this issue, and some have proposed using improved particle swarm algorithms to optimize the capacity of microgrids and improve the economic benefits of energy storage. |
| Microgrid Energy Management Research Status | The energy management system of microgrids is facing more and more challenges with the rapid development of the smart grid. The functions of the microgrid energy management system include monitoring the operating status, establishing a reasonable charging and discharging management strategy for energy storage equipment, real-time monitoring of microgrid information, predicting the power of renewable energy generation and loads, formulating a power distribution scheme according to the user’s power strategy, and realizing the power allocation of power generation resources. At present, the research on microgrid energy management mainly focuses on the centralized control structure, but the hierarchical control structure is gradually being adopted, which can improve the stability and efficiency of the system. |
| Photovoltaic Grid-Connected Research Status at Home and Abroad | The development of photovoltaic grid-connected power generation began in the early 1980s, and countries such as the United States, Japan, and Germany were relatively advanced in the early stages. In the early days, the idea was to build large-scale photovoltaic grid-connected power stations and experimental power stations with high investment costs. Later, the focus shifted to the construction of distributed photovoltaic power stations, which are more flexible and economical. However, the development of the photovoltaic industry in different countries has faced different challenges. For example, Japan has faced high costs and the impact of imported components, while the United States has experienced changes in policies and the COVID-19 pandemic, which have affected the development speed of photovoltaic power. Currently, China is in a stage of rapid development in photovoltaic power, with continuous expansion of the market application. The industrial chain of photovoltaic cell modules in China has been mature and complete, and the industrialization and mass production technology has reached the world’s leading level. |
In this paper, based on the “Distributed Photovoltaic Power Generation Capacity Expansion Project in a County Plant in Linyi City,” a photovoltaic energy storage integrated microgrid system is established through MATLAB/Simulink by selecting the photovoltaic panels, inverters, and other components of the project. The energy management of the microgrid in both isolated and grid-connected operation modes is carried out, and the improved particle swarm algorithm is used to solve the proposed microgrid model and energy management strategy to verify the effectiveness and reliability of the distributed energy management strategy in the photovoltaic energy storage integrated microgrid system in improving economic benefits, and to apply it to the project as a whole.