MPPT's full English name is Maximum Power Point Tracking, meaning maximum power point tracking. MPPT solar controller translated too is the maximum power point tracking solar controller, is the traditional solar charge and discharge controller upgrade products. The so-called Maximum Power Point Tracking means that the controller can detect the power generation voltage of the solar panel in real time and track the highest voltage and current value (VI) to make the system charge the battery with the highest efficiency. Below we discuss the basic principles, functions, advantages and trends of MPPT solar controllers compared to traditional controllers.
MPPT Overview
It is an electrical system that enables the photovoltaic panels to output more power by adjusting the working state of the electrical modules. It can effectively store the DC power emitted by the solar panels in the battery, which can effectively solve the problem of living and industrial power consumption in remote areas and tourist areas that cannot be covered by the conventional power grid, without producing environmental pollution. The output power of the PV cell is related to the working voltage of the MPPT controller, and its output power will have a unique maximum value only if it works at the most suitable voltage. The sunlight intensity is 1000W/under, U=24V, I=1A; U=30V, I=0.9A; U=36V, I=0.7A; it can be seen that the output power is maximum under the voltage of 30.
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, then the output current will be close to 0. Therefore, for safety reasons, the peak voltage (Vpp) of the solar panel is about 17V when the solar panel is manufactured in the factory, which is set at the ambient temperature of 25°C. When the weather is very hot, the peak voltage Vpp of the solar panel drops to about 15V, but in cold weather, the peak solar voltage Vpp can reach 18V.
The traditional solar charge and discharge controller is a bit like a manual gearbox, when the engine speed increases, if the gearbox gears are not raised accordingly, it will inevitably affect the speed of the car. But for traditional controllers, the charging parameters are set before leaving the factory, which means that the MPPT controller will instantly track the maximum power point in the solar panel to bring out the maximum effectiveness of the solar panel. The higher the voltage, the more power can be output by maximum power tracking, thus increasing the charging efficiency. Theoretically, a solar power system using MPPT controllers will be 50% more efficient than conventional ones, but according to our actual tests, the final efficiency can also be increased by 20%-30% due to the influence of the surrounding environment and various energy losses.
In this sense, MPPT solar charge/discharge controller is bound to replace the traditional solar controller eventually.
Functions of MPPT
The main function of MPPT controller: detect the main circuit DC voltage and output current, calculate the output power of the solar array, and realize the tracking of the maximum power point. The disturbance resistor R and MOSFET are connected in series. Under the condition that the output voltage is basically stable, the average current through the resistor is changed by changing the duty cycle of the MOSFET, thus creating a disturbance of the current. At the same time, the PV cell output current and voltage will also change, by measuring the PV cell output power and voltage changes before and after the perturbation, in order to decide the next cycle of the perturbation direction, when the perturbation direction is correct solar panel output power increase, the next cycle continue to perturbation in the same direction, and vice versa, perturbation in the opposite direction, so, repeatedly perturbation and observation to make the solar photovoltaic panel output up to the maximum power point .
