The independent photovoltaic power generation system is relative to the grid-connected power generation system and belongs to an isolated power generation system. The isolated system is mainly used in remote areas without electricity, and the main purpose of its construction is to solve the problem of lack of electricity. Its power supply reliability is greatly affected by factors such as meteorological environment and load, and the power supply stability is relatively poor. In many cases, energy storage and energy management equipment need to be installed.
Classification of stand-alone photovoltaic power generation systems
Independent photovoltaic power generation system is also called off-grid photovoltaic power generation system. It is mainly composed of solar cell components, controllers, and batteries. To supply power to the AC load, an AC inverter needs to be configured. Independent photovoltaic systems can be divided into two categories: DC photovoltaic power generation systems and AC photovoltaic power generation systems.
1. DC photovoltaic power generation system
1. DC photovoltaic power generation system without battery
The characteristic of the battery-free DC photovoltaic power generation system is that the electrical load is a DC load, there is no requirement for the load usage time, and the load is mainly used during the day. The solar cell is directly connected to the electrical load. When there is sunlight, it generates electricity for the load to work, and when there is no sunlight, it stops working. The system does not require the use of a controller and there is no battery storage device. The advantage of the battery-free DC photovoltaic power generation system is that the loss caused by the energy passing through the controller and the storage and release of the battery is eliminated, and the solar energy utilization efficiency is improved. The most typical application of this kind of system is the solar photovoltaic water pump.
2. DC photovoltaic power generation system with battery
A DC photovoltaic power generation system with a battery consists of a solar cell, a charge and discharge controller, a battery, and a DC load. When there is sunlight, the solar cell converts the light energy into electrical energy for the load to use, and at the same time stores the electrical energy to the battery. At night or in cloudy and rainy days, the battery supplies power to the load. This system is widely used, ranging from solar lawn lights and garden lights, to mobile communication base stations, microwave transfer stations far away from the power grid, and rural power supply in remote areas. When the system capacity and load power are large, solar cell arrays and battery packs are required.
2. AC photovoltaic power generation system
1. AC and AC and DC hybrid photovoltaic power generation systems
Compared with the DC photovoltaic power generation system, the AC photovoltaic power generation system has an additional AC inverter, which is used to convert the DC power into the AC power and provide power for the AC load. The AC and DC hybrid photovoltaic power generation system can supply power for both DC loads and AC loads.
2. Mains complementary photovoltaic power generation system
The commercial power complementary photovoltaic power generation system is mainly based on solar photovoltaic power generation in the independent photovoltaic power generation system, supplemented by ordinary 220V alternating current supplementary electric energy. In this way, the capacity of solar cells and storage batteries in the photovoltaic power generation system can be designed to be smaller. Basically, when there is sunshine on the day, the electricity generated by the solar energy is used on the same day, and when it is rainy, the mains energy is used to supplement it. Most areas in my country have had more than 2/3 sunny weather for many years. This form not only reduces the one-time investment of solar photovoltaic power generation systems, but also has significant energy saving and emission reduction effects. It is the promotion and popularization process of solar photovoltaic power generation at this stage. A great way to over-sex.
Application of independent photovoltaic power generation system
Independent photovoltaic power plants are also called isolated photovoltaic power plants. Independent photovoltaic power plants are suitable for the establishment of independent photovoltaic power plants in villages, towns and islands with relatively good lighting conditions and relatively large load demand, and in powerless Han areas where users are relatively concentrated within a few kilometers. The capacity of photovoltaic power plants ranges from several kilowatts to tens of kilowatts. The power station consists of photovoltaic panel arrays, batteries and converters, energy generators, power distribution and transmission systems. The power generation system completes the charging of the battery in the daytime, and at the same time supplies power to the photovoltaic water pump, processing machines, etc., performs water pumping, water storage and processing operations, and completes the inverter discharge control of the battery at night to realize the power supply to the load. When designing an independent power station , Considering the rational use of the battery is a very important part, especially for the motor-type dynamic load that uses electricity at night or has a high ratio of electricity consumption.