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This post was last edited by chenjinfeng88 on 2020-9-30 at 17:20. Several typical distributed DC power supplies. As is well known, wind energy is an environmentally friendly resource; it is clean and sustainable, and it can be replenished. Given that the global reserves of wind energy are very large and its available amount is higher than that of other renewable resources, in an era where energy reserves are becoming increasingly scarce, wind energy, as an environmentally friendly renewable resource, has attracted increasing attention and research from various countries regarding its development methods and efficiency of utilization. Wind power generation refers to the use of advanced technical methods to convert wind energy into electrical energy. Specifically, wind turbines first capture the energy from the wind, which then drives generators to produce electricity. The electricity generated is subsequently processed by electronic controllers before being fed into the power grid. Wind power generation is the most mature and common form of power generation among distributed DC power sources. According to data from the GWEC (Global Wind Energy Council), in 2011 alone, the global capacity added to wind power systems reached 41 GW, bringing the total installed capacity to 238 GW, with an annual growth rate of 21%. This figure indicates that wind power development has entered a formal phase on a global scale, and it also shows that countries around the world have recognized and accepted the positive contributions of wind power to the electricity sector. Wind turbines can be divided into two types based on their structure: synchronous generators and asynchronous generators, each with its own advantages and disadvantages. For synchronous generators, the grid connection circuit can decouple the active and reactive powers between the generation side and the power grid side; therefore, it enables reactive power compensation, which improves the low-voltage ride-through capability of the grid connection point. Moreover, this circuit can separate the power grid side from the generation side, allowing it to isolate faults. However, synchronous generators also have their drawbacks. Firstly, they are large in size, have a complex structure, and incur high costs for installation and maintenance. Additionally, their output power is greatly affected by wind speed, which can easily cause fluctuations in the power grid ； The advantage of asynchronous generators is their simple structure, which makes installation and maintenance easier. However, their ability to operate under low voltage conditions is relatively poor, and they generate a large amount of harmonics during power generation, affecting the quality of electricity. Although asynchronous generators are currently the main type used in wind power generation, as the electricity sector continues to increase its installed capacity and imposes stricter requirements on power quality, it is believed that they will be replaced in the near future by synchronous generators with full-power conversion capabilities. Like other renewable energy sources, wind power also has advantages such as abundant resources, energy efficiency, and flexibility in installation and operation. However, some disadvantages cannot be ignored, mainly including instability and uncontrollability due to its strong dependence on environmental wind speeds. (1) Instability: The power of wind turbines is affected by wind speed, and since wind speed is constantly changing, it is difficult to predict the turbine power; as a result, wind power generation exhibits high instability. (2) Uncontrollability: Wind turbines generate electricity by using wind power to drive the generators; however, wind is uncontrollable, and wind energy cannot be stored in large quantities. Therefore, wind power generation is uncontrollable. Photovoltaic power generation is what is commonly referred to as solar power generation. Like wind energy, solar energy is a renewable resource that is environmentally friendly and abundant. Photovoltaic power generation involves using semiconductor materials, namely solar cells, and their photovoltaic effect to convert solar energy into electrical energy. The principle behind this is that when light shines on semiconductor materials, it excites the electrons and holes within them; these particles move toward the two poles of the cell under the influence of an internal electric field, thereby generating an electric current and producing electrical energy. The semiconductor materials that are widely used today mainly include single-crystalline silicon, polycrystalline silicon, and amorphous silicon; sometimes semiconductor compounds such as indium phosphide and gallium arsenide are also used. In practical applications, several solar cells are assembled into photovoltaic modules. When light shines on these modules, high-voltage direct current is generated; this high-voltage direct current is then converted by an inverter into sinusoidal alternating current with the same frequency and phase as that of the power grid, before being fed into the grid. Photovoltaic power generation is also a form of power generation recognized and accepted by countries around the world. It boasts several unique advantages, such as minimal geographical constraints, simple equipment, low costs, easy installation, high reliability, and straightforward maintenance. Especially these days, as the cost of photovoltaic power generation equipment continues to decline, photovoltaic power generation has seen unprecedented development. Data from the European Photovoltaic Industry Association show that in 2010 alone, the global installed capacity for photovoltaic systems reached 39.7 GW, and this figure rose even further in 2011, with an increase of 67%. This clearly demonstrates the global interest in photovoltaic power generation as well as the huge market potential associated with it. We can be certain that, with further advancements in technology, solar photovoltaic power generation will become widely used for both industrial electricity needs and residential power consumption. A fuel cell is a power generation device that can convert chemical energy directly into electrical energy. Its working principle is similar to that of ordinary batteries, and it represents an efficient and environmentally friendly method of power generation; the chemical energy used in this process comes primarily from hydrogen-rich fuels. Fuel cell power generation technology has made tremendous progress and development in recent years thanks to the joint efforts of various sectors. Depending on the type of electrolyte, fuel cells offer numerous advantages in terms of power generation efficiency, convenience, and safety. Their main features include: (1) Wide range of energy sources: Traditional fuels such as oil, coal, and natural gas can all be used as energy sources for fuel cells, providing a quite diverse range of options ； (2) High conversion efficiency: Fuel cells have a power generation efficiency that is much higher than that of other power generation methods, reaching 80%~95%. They are the most efficient among distributed power generation systems, and this high efficiency remains constant regardless of load changes, offering excellent controllability ； (3) Low pollution: During the power generation process, fuel cells do not emit pollutants into the environment, resulting in high environmental cleanliness; at the same time, they generate almost no noise ； (4) Simple construction and maintenance: The construction of fuel cells is not subject to environmental constraints, and expansion is easy. At the same time, fuel cells feature a modular structure, allowing them to be used in both distributed and integrated configurations; they are easy to install and require little space. Micro gas turbines: The term “micro” in micro gas turbines refers to their power output, which is only in the range of dozens to a few hundred kilowatts. Their fuel source, similar to that of fuel cells, is mainly traditional fuels such as natural gas, gasoline, and diesel. The structure of a micro gas turbine includes a centrifugal compressor, a radial turbine, a combustion chamber, a regenerator, a high-speed inverter generator, and electronic control devices. The high-temperature gases generated by fuel combustion are fed into a centrifugal turbine mechanism to generate power, which in turn drives a generator to produce alternating current. After rectification and inversion, this electricity can be connected to the power grid. Micro-turbines are small in size, highly reliable, and environmentally friendly; they also offer higher efficiency compared to existing power generation equipment, with efficiencies of up to 75% in combined heat and power applications. At present, micro-turbine power generation technology is already quite mature and has been widely applied, boasting high commercial competitiveness. Biomass power generation: This technology first converts biomass energy into combustible forms of energy such as alcohol or fuel, and then burns these to drive generators and produce electricity. Although this form of power generation has not yet been widely used in our country, it has reached a level of large-scale production abroad. The capacity of each unit involved is now in the range of hundreds of megawatts. Moreover, the ash and slag generated during power generation are reused, and all emission standards are met, which helps to effectively reduce carbon dioxide emissions. This approach enables resource recycling while also being environmentally friendly. The characteristics of distributed biomass energy power sources include the following: (1) Renewability: Biomass energy generally comes from sources such as straw, rice straw, and wood chips, and it constitutes a renewable resource ； (2) Low pollution: The ash and residues generated by biomass power generation can generally be reused, and they can be degraded by the environment after being emitted; moreover, very few polluted gases are released ； (3) Universality: Areas where biomass power generation can be utilized are extremely widespread, especially in rural towns and villages where there is a large amount of straw waste; these areas are also the main sites for biomass energy power generation.