Classification And Application of Independent Photovoltaic Power Generation Systems
An independent photovoltaic power generation system is also called an off-grid photovoltaic power generation system. A typical independent photovoltaic power generation system consists of a solar array and a battery connected to it. When there is sunlight, the photovoltaic array provides power to the load and charges the battery, otherwise the battery provides power to the load. An inverter is used to convert the DC power from the array and battery to 60Hz or 50Hz power.
Classification of Independent Photovoltaic Power Generation Systems
The independent photovoltaic power generation system is mainly composed of solar cell modules, 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
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
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 AC power supplementation. In this way, the capacity of solar cells and 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 solar energy is used that day, and when it is rainy, the mains energy is used to supplement it. Most parts of our country have more than 2/3 of fine weather for many years. This form not only reduces the one-time investment of the solar photovoltaic power generation system, but also has a significant energy saving and emission reduction effect.
