Classification of independent photovoltaic power generation system

Classification of independent photovoltaic power generation system

Independent photovoltaic power generation system is an isolated power generation system compared with grid connected power generation system. Isolated system is mainly used in remote areas without electricity, and the main purpose of its construction is to solve the problem of no electricity. Its power supply reliability is greatly affected by meteorological environment, load and other factors, and the power supply stability is relatively poor. It is often necessary to install energy storage and energy management equipment.

Classification of independent photovoltaic power generation system

Independent photovoltaic power generation system is also called off grid photovoltaic power generation system. It is mainly composed of solar cell module, controller and battery. If you want to supply power to AC load, you also need to configure AC inverter. Independent photovoltaic systems can be divided into DC photovoltaic power generation systems and AC photovoltaic power generation systems.

DC photovoltaic power generation system

(1) DC photovoltaic power generation system without battery

The characteristic of DC photovoltaic power generation system without battery is that the power load is DC load, there is no requirement for the service time of the load, and the load is mainly used in the daytime. The solar cell is directly connected with the electric 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 a controller and there is no battery energy storage device. The advantage of DC photovoltaic power generation system without battery is that it eliminates the loss of energy through the controller and in the storage and release process of battery, and improves the utilization efficiency of solar energy. The most typical application of this system is solar photovoltaic water pump.

(2) DC photovoltaic power generation system with battery

The DC photovoltaic power generation system with battery is composed of solar cell, charge discharge controller, battery and DC load. When sunlight enters, the solar cell converts light energy into electric energy for load use, and stores electric energy to the battery at the same time. At night or in rainy days, the battery supplies power to the load. This system is widely used, ranging from solar lawn lamps and courtyard lamps to mobile communication base stations and microwave transfer stations far away from the power grid, rural power supply in remote areas, etc. When the system capacity and load power are large, it needs to be equipped with solar cell array and battery pack.

AC photovoltaic power generation system

(1) AC and AC / DC hybrid photovoltaic power generation system

AC and AC / DC hybrid photovoltaic power generation system compared with DC photovoltaic power generation system, AC photovoltaic power generation system has an AC inverter to convert DC power into AC power and provide electric energy for AC load. AC / DC hybrid photovoltaic power generation system can supply power for both DC load and AC load.

(2) Commercial power complementary photovoltaic power generation system

The utility complementary photovoltaic power generation system is based on solar photovoltaic power generation in the independent photovoltaic power generation system, supplemented by ordinary 220V AC supplementary electric energy. In this way, the capacity of solar cells and batteries in the photovoltaic power generation system can be designed to be smaller. Basically, there is sunshine on the same day, and the electricity generated by solar energy on the same day will be supplemented with municipal electricity energy in rainy days. Most parts of China have more than two-thirds of the sunny weather for many years. This form not only reduces the one-time investment of solar photovoltaic power generation system, but also has significant energy-saving and emission reduction effect. It is a good way to promote and popularize solar photovoltaic power generation at this stage.