The off-grid photovoltaic power generation system consists of photovoltaic modules, controllers, off-grid inverters, batteries and power distribution systems. The working principle of the off-grid photovoltaic power generation system is very similar. The only difference is that the power output by the off-grid system is It is directly consumed and used without being transmitted to the power grid. For remote mountainous areas, non-electric areas, communication bases, etc., the off-grid photovoltaic power generation system is a perfect solution to solve the electricity demand.
Common solar panel include monocrystalline silicon modules, polycrystalline silicon modules, and amorphous silicon modules. Among them, monocrystalline silicon modules have the highest conversion efficiency and the smallest volume, but the cost is also the highest. The off-grid solar power generation system uses solar cell components as the power generation components, and is the most important component in the solar power supply system. Its function is to convert the radiant energy of the sun into direct current electricity.
(2) Controller
Popular solar controllers mainly include ordinary solar controllers, PWM solar controllers and MPPT solar controllers. MPPT solar controller is the third generation technology, the most high-end solar controller at present. MPPT solar controller refers to a solar controller with the function of "maximum power point tracking". It is an upgraded product of PWM solar controller. The MPPT solar controller can make the system always charge the battery with the maximum power. The MPPT tracking efficiency is 99%, the power generation efficiency of the whole system is as high as 97%, and it has excellent management of the battery. The controller adjusts and controls the electric energy generated by the solar modules. On the one hand, the adjusted energy is sent to the DC load or the AC load, and on the other hand, the excess energy is sent to the battery pack for storage. When the generated electricity cannot meet the load When needed, the controller sends the power of the battery to the load. After the battery is fully charged, the controller should control the battery not to be overcharged. When the electric energy stored in the battery is discharged, the controller should control the battery not to be over-discharged to protect the battery.
(3) Battery
At present, there are four main types of batteries used in solar power generation systems on the market, namely lead-acid batteries, gel batteries, ternary lithium batteries and lithium iron phosphate batteries. The main task of the battery is to store energy. It converts the DC power converted from the solar radiation energy by the solar cell array into chemical energy and stores it, so as to ensure the load power at night or in cloudy and rainy days.
(4) Inverter
Many electrical appliances use alternating current, and the power grid in daily life also uses alternating current transmission. Therefore, after the DC power supply is available, a power converter is required. The technical term is inverter, and the inverter is the core of the off-grid power generation system. The component is responsible for converting DC power to AC power for use by AC loads. According to the AC voltage waveform, we can also divide the inverters into square wave inverters, modified wave inverters, and sine wave inverters. Among them, the output waveform of the sine wave inverter is good, with little interference to communication equipment and noise. In order to improve the overall performance of the photovoltaic power generation system and ensure the long-term stable operation of the power station, the performance indicators of the inverter are very important.
(5) Load
There are also many points to pay attention to in the selection of the load of the photovoltaic power generation system. We should choose the load power according to the capacity of the battery. The basic requirement is that in normal sunshine, the solar energy that the battery can store every day can meet the electric energy used by the load for a day or there is a surplus. , and the total power size of the load should not exceed the output power of the solar panel or controller.
