Photovoltaic off-grid solar system application scenarios and solutions

The main users of small off-grid solar systems come from poor and powerless areas, remote mountainous areas, herdsmen and tourists, mainly to solve lighting, mobile phone charging and other needs; the system's daily electricity consumption is less than 5 degrees, and the load power is less than 1kW; Users' demand for electricity is not very urgent, and their demands for products are simple, reliable and cheap. Therefore, it is recommended to use a PWM controller and a modified wave inverter to integrate the controller, inverter and battery.

Small and medium-sized off-grid solar systems can be used in relatively wealthy areas lacking power, such as herdsmen, island residents, medium-sized fishing boats, relatively remote scenic spots, and some communication and monitoring base stations. Mainly to solve the basic needs of life such as lighting, TV, fans, air conditioners, etc.; the system's daily electricity consumption is less than 50 degrees, and the total load power is less than 20kW.

Medium and large off-grid solar energy systems are mainly used in industrial and commercial areas, scenic spots and other places with frequent power outages, high electricity prices, large peak-to-valley price differences, and photovoltaics cannot be connected to the Internet to meet the electricity needs of people's daily life, offices, and commercial activities. Mainly; the system load power is above 20kW and below 250kW, and the daily power consumption is below 500 degrees. There are many solutions for small and medium-sized off-grid systems.
For systems above 20kW and below 60kW, you can choose the parallel networking solution of multiple single-phase small off-grid inverters. Relatively speaking, the wiring and debugging of this solution are more complicated, but the price is relatively cheap and the flexibility is high. Even if the inverter fails, the system can continue to operate. You can also choose the split solution of controller and inverter and the integrated solution of controller and inverter. Using a medium and large single inverter, the system wiring is simple and debugging is convenient. It can be combined with a fuel generator set to form a hybrid power supply system. Compared with pure off-grid photovoltaics, a large number of expensive batteries can be saved, and the comprehensive power generation cost is low. Systems above 60kW currently have two topologies: DC coupling "DC Coupling" and AC coupling "AC Coupling", which can be selected according to power consumption.

Large-scale multi-energy off-grid solar energy systems are mainly used in remote mountainous areas, islands, tourist areas, industrial and commercial areas with high electricity prices and other places without power grids and large populations. The power is above 250kW. Currently, the single unit power is 250kW off-grid inverter. There are few devices, and bidirectional energy storage converters are generally used. Grid-connected inverters and batteries are combined into microgrid systems. In addition to photovoltaics and energy storage, there are usually other types of power generation devices such as wind turbines and fuel generators. At present, most microgrids adopt AC coupling topology, using centralized inverters and bidirectional energy storage converters.