The capacity of individual photovoltaic cells is extremely small, so an array approach is generally adopted. The array principle is to combine individual photovoltaic cells in series or parallel to form a photovoltaic array, and then construct a photovoltaic power generation system. According to the relationship with the power grid, solar inverters can be divided into independent solar inverters and grid connected transformers. According to the output waveform, they can also be divided into sine wave solar inverters, square wave solar inverters, and stepped wave solar inverters; Similarly, the single-phase, three-phase, and multiphase solar inverters referred to collectively are defined based on the phase of the output current. In today’s world, there are mainly several types of solar inverters that use solar inverters, including series, centralized, multi series, and modular inverters. The following text describes several basic structures of inverters. A solar inverter combined with modular concepts is called a string solar inverter. Among them, each string is connected to the grid by setting a solar inverter at the AC end and a solar inverter with maximum power tracking at the DC end. This type of solar inverter is widely used in many photovoltaic power plants, and its advantage is to reduce the optimal operating point of photovoltaic modules, without module differences and shading limitations between strings.
A centralized solar inverter is a device that connects a large number of parallel photovoltaic modules in series to the DC input side of the same solar inverter. Different devices are selected for connection according to the power size, but the output electrical energy is not a standard sine wave current. Therefore, a controller is needed to improve the electrical energy quality to approximate the sine wave current. However, this type of solar inverter has a more complex structure and is more suitable for small and medium-sized photovoltaic power plants.
Generate multiple series solar inverters by combining the advantages of centralized and series solar inverters. It has a wider range of applications and can be used in photovoltaic power plants with thousands of volts. Each individual component in the multi group Shen solar inverter has the function of maximum power tracking, and also has a DC/DC converter that allows direct current to be converted into alternating current through the DC/AC converter for use by AC loads or directly connected to the system. The selection of components in multi string solar inverters is also relatively flexible. Photovoltaic modules produced by different manufacturers, with different rated power, different number of components, different sizes, and different technologies can be connected together, and can work in coordination at their respective maximum power points. Connect each photovoltaic module to a solar inverter and provide an independent maximum power tracking. In this method, the coordination between the solar inverter and the module is good, but the overall efficiency is still lower than that of the string solar inverter, and the wiring is complex, Due to maintenance difficulties and the current trend of requiring photovoltaic power generation to be connected to the grid, the application of modular solar inverters will have to solve many important problems. Therefore, this type of solar inverter is usually applied to glass curtain walls.
Solar power generation system inverters include single-phase voltage source solar inverters and three-phase solar inverters. The most common type of solar inverter is a single-phase power type solar inverter. It is an inverter method that uses voltage control to convert electrical energy from DC to AC. Three phase solar inverters are specifically divided into three-phase voltage source and three-phase current source solar inverters based on the characteristics of DC power sources. Due to the influence of factors such as component power capacity and negativity, as well as load characteristics, single-phase solar inverters have low capacity. Therefore, when the capacity of the inverter circuit is large, three-phase solar inverters are usually selected.