With the advancement of science and technology, solar power generation has gradually come to the public from the application of spacecraft, and can be seen almost everywhere. In addition to large-scale photovoltaic power stations, rooftop photovoltaic power stations, solar street lights, solar toys, etc., it basically involves all areas of life.

As we all know, the intensity of sunlight is unstable. To obtain a stable and reliable power supply, voltage stabilization and energy storage are required. In large-scale photovoltaic grid-connected power stations, voltage and frequency stabilization are required to protect the stable operation of the power grid. In small off-grid applications, the controller is required to limit the charging voltage and charging current during the charging and discharging process to prevent the energy storage battery from overcharging, over-discharging, overheating, short circuiting, etc. Protect the safety and service life of the energy storage equipment; and prevent the energy storage battery from over-discharging and over-current during the discharge process.

Off-grid solar controllers are currently divided into two charging mode controllers. One is a PWM pulse charging controller, which can automatically charge in time periods according to the battery type (full charge, strong charge, balanced charge, floating charge). The other is the MPPT maximum power tracking point charging mode, which detects the maximum power point of the solar panel in real time according to the working voltage and automatically adjusts the charging power.
The selection principle of off-grid solar power supply is based on three data: one is the system operating voltage, two is the solar panel input power, and three is the DC load power.
There are two typical applications of solar controllers, one is DC power supply system application, the other is AC power supply system application. The following is a simplified application diagram:

1. DC power supply system diagram

2. AC power supply system diagram

Solar power supply systems have a wide range of applications, from spacecraft to solar flashlights. There are many common and mature applications, such as: solar street lights, solar traffic lights, solar navigation lights, solar portable power generation systems, water conservancy and hydrological monitoring solar power supply systems, field video surveillance solar power supply systems, earthquake and geological monitoring solar power supply systems, border post solar/wind complementary power supply systems, island solar/wind and other multi-energy complementary power supply systems, oil and gas pipeline cathodic protection solar/wind power supply systems, forest fire prevention solar/wind power supply systems, etc.
Solar/wind power supply systems are usually applied in remote areas, and the operation and maintenance costs are relatively high. It is recommended to choose a strong company to cooperate with when designing a solar/wind power generation system. The solar/wind controller is the core of the system operation. If a fault occurs, the entire system will not operate normally.