[science Popularization] know MPPT (Solar Controller) Air defense zone over South China Sea an option)
Overview of MPPT
MPPT system is an electrical system that can output more electric energy by adjusting the working state of the electrical module. It can effectively store the direct current generated by solar panels in storage batteries. It can effectively solve the domestic and industrial power consumption in remote areas and tourist areas where the conventional power grid can not cover, and does not cause environmental pollution.
The output power of photovoltaic cell is related to the working voltage of MPPT controller. Only when it works at the most suitable voltage can its output power have a unique maximum.
Sunshine intensity is 1000W/a, U = 24V, I = 1A; U = 30V, I = 0.9A; U = 36V, I = 0.7A; visible 30 voltage output power is the largest.
Principle of MPPT
To charge the battery, the output voltage of the solar panel must be higher than the current voltage of the battery. If the voltage of the solar panel is lower than the voltage of the battery, the output current will be close to 0. Therefore, in order to be safe, the peak voltage (Vpp) of solar panels is about 17V when they are manufactured and manufactured, which is set at the ambient temperature of 25 degree C. When the weather is very hot, the peak voltage Vpp of solar panels will drop to about 15V, but in cold weather, the peak voltage Vpp of solar panels can reach 18V.
The traditional solar charge and discharge controller is somewhat like a manual transmission. When the engine speed increases, if the gear of the transmission does not correspondingly improve, it will inevitably affect the speed of the vehicle. But for the traditional controller, the charging parameters are set before the factory, that is to say, MPPT controller will track the maximum power point in the solar panel in real time, to give full play to the maximum efficiency of the solar panel. The higher the voltage, the more power can be output through maximum power tracking, thus improving the charging efficiency. In theory, the efficiency of solar power generation system using MPPT controller will increase by 50% compared with the traditional one, but according to our actual test, due to the environmental impact and various energy losses, the ultimate efficiency can also be increased by 20% - 30%.
In this sense, MPPT solar charge and discharge controller will eventually replace the traditional solar controller.
Functions of MPPT
The main function of MPPT controller is to detect DC voltage and output current of main circuit, calculate the output power of solar array, and track the maximum power point. The disturbance resistance R and MOSFET are connected in series. Under the condition of stable output voltage, the average current through the resistor is changed by changing the duty cycle of the MOSFET, so the disturbance of the current is produced. At the same time, the output current and voltage of photovoltaic cells will also change. By measuring the output power and voltage of photovoltaic cells before and after disturbance, the disturbance direction of the next cycle can be determined. When the disturbance direction is correct, the output power of solar panels will increase, and the next cycle will continue to perturb in the same direction. On the contrary, the next cycle will perturb in the opposite direction. Thus, disturbance and observation will be repeated to make the disturbance. The output of solar photovoltaic panels reaches the maximum power point.