(1) Controller. The function of the controller is to make the solar cells and storage batteries work efficiently, safely and reliably to obtain the highest efficiency and prolong the service life of the storage batteries. The controller controls the charging and discharging of the battery, and according to the power demand of the load, controls the solar cell components and the battery to output electrical energy to the load, which is the control core of the entire solar LED lighting system. The controller limits the charging and discharging conditions of the battery to prevent reverse charging, overcharging and overdischarging of the battery. In addition, it should have functions such as circuit short-circuit protection, reverse connection protection, lightning protection and temperature compensation. Since the output energy of solar cells is extremely unstable, the quality of the controller’s charge and discharge control circuit is very important for the design of solar power generation systems.
The controller should make the solar cells in the solar LED lighting system always be near the maximum power point of power generation to obtain the highest efficiency. The charge control usually adopts pulse width modulation technology, that is, PWM control mode. Discharge control mainly refers to cutting off the switch when the battery is short of power or the system is faulty, such as the battery is open or connected reversely.
The controller integrated with the LED driver should have the characteristics of driving the LED with constant current, so that the current flowing through the LED does not change with the voltage of the battery. And has a light control function, automatically turn off the light at dawn, and automatically turn on the light when dark. And can determine the working status of the system by detecting the output of the solar cell and the power of the battery, and realize the automatic control and intelligent management of the entire system.
(2) LED light source. LED has the advantages of high light quality, basically no radiation, reliability and durability, and extremely low maintenance costs. It is a typical green lighting source. The successful development of ultra-bright LED has greatly reduced the use cost of solar LED lighting, making it reach or close to the cost of initial installation of power frequency AC lighting system, and has the advantages of environmental protection, easy installation, safe operation, economical and energy-saving. Due to the advantages of high light efficiency and low heat generation, LEDs have been increasingly used in the field of lighting and are showing a trend to replace traditional lighting sources.
The column and rectangular combined light source structure of the flat-head LED is adopted. By reasonably controlling the installation tilt angle of the flat-head ultra-high-brightness white light LED, the uniformity and illuminance of the light emitted by the LED combined light source can be greatly improved. The combined cross-shaped and rectangular combined light sources specially developed for the field of solar LED street lights give full play to the advantages of flat-head LEDs, such as large luminous angle, good light uniformity, and high brightness of round-head LED dot area, so that the two can complement each other and maximize the light efficiency. It overcomes the shortcomings that the brightness of the flat head LED is not as good as the round head LED, and the light uniformity of the round head LED is not as good as the flat head LED. Through the update and technical improvement of the traditional solar lighting fixture structure, intelligent controller, reflection angle, the optimal tilt angle design, so that the advantages of flat and round LEDs complement each other, so that it can emit light more uniformly, the overall brightness is higher, the cost is lower, and it is more conducive to the application and promotion of solar LED lighting fixtures.
Therefore, for an independent solar LED lighting system, improving energy utilization and studying scientific system energy control strategies can reduce the investment cost of an independent solar LED lighting system. At present, solar cell modules, controllers, batteries, and LED lighting sources are the four main modules of solar LED lighting products.