What parameters should be known in the design of off-grid inverter solar power generation system?
Off-grid solar inverter systems are different from our grid-connected systems.
It exists on its own, so when we design solar systems off-grid, we must first know what factors will constrain it. In particular, off-grid household inverter solar power generation system is composed of solar photovoltaic module, fixed bracket, solar controller, solar inverter, solar cell and distribution system. Therefore, when designing off-grid power generation system, this aspect must be considered first.
First, the power of the off-grid inverter host should be determined according to the type of load and the total power of the load
Because the off-grid inverter solar power generation system is independent, it must provide a stable power supply for the whole system. Family load can be divided into inductive load and resistive load. Special attention should be paid to the inductive load of electric motors (such as washing machines, air conditioners, refrigerators, pumps and exhaust fans).
The motor starts at three to five times the rated power. The starting power of these loads must be considered when calculating the inverter power. The output power of off-grid inverter is greater than the load power, and the sum of the actual load power is usually designed to account for less than 70~80% of the host output power. Second, according to the user's electricity consumption, determine the power size of the solar module
The design of the solar panel components of the off-grid inverter solar system shall be based on the user's daily electricity consumption and the conversion efficiency of the solar panel. Usually, the minimum requirement to meet solar panel power generation is higher than the user's daily power consumption. However, as the sun and weather conditions (cloudy days) vary in each region, we have to make a compromise. Of course the best requirement is a one-use, one-charge design is the power source of the solar panel module. It is necessary to estimate the daily power consumption of the user and the daily charging capacity of the battery pack throughout the day in order to minimize the loss of the battery so that the battery can be surface treated in most discharge states, thus effectively extending the battery life.
To know the user's electricity consumption at night and the expected standby time without sunshine, determine the capacity of the battery pack. In the off-grid inverter solar power generation system, night is the time when the battery is mainly used for energy storage.
That is, from the period of daylight loss, to confirm the user's power consumption at night, we must determine the size of the battery. If you don't know, you must expect how long the wait will be, that is, no sunny days, which could be one night, one day, or two days.
Of course, the expected time directly affects the cost of the battery. Therefore, in order to minimize costs and better estimate electricity consumption at night, we can also calculate this value using charging power and usage time at night.