Led lamp driver modelling

Currently, there is an increase in the use and production of energy-saving lamps of various types – fluorescent and LED ones. However, it has been found that the use of technologies that have proven themselves in the creation of luminescent sources for LED light sources is ineffective. The use of traditional secondary optics for LED luminaires makes it difficult to create an effective heat sink from LEDs, while the durability of LEDs significantly depends on the heat sink. Another important issue when designing LED luminaires is choosing the right driver. The power consumption of LEDs from the primary network depends on the efficiency of the driver used. The choice of the type of driver also determines the amount of heat that should be removed from its elements. A significant factor influencing the choice of a driver is also the possibility of its operation in conjunction with a voltage regulator – a dimmer, in order to control the illumination. It is also necessary to take into account the IEC recommendations that require manufacturers to use active power factor correctors for devices with switching power supplies and / or electronic ballast with a power of 20 watts or more. Therefore, there is a task of developing a highly efficient driver for use in LED luminaires. In the process of reviewing modern drivers, a driver based on the LT3799 microcircuit from Linear Technology was selected for further research, which is distinguished by high efficiency, working with a large number of produced LEDs, has a built-in active power factor corrector, and allows the use of dimmers. The inclusion of the driver chip recommended by the manufacturer was applied, with the addition of noise suppressing components. The galvanic isolation of the power supply circuits of the LED matrix is provided. Next, the analysis of the characteristics of the selected circuit design solution is carried out using computer simulation. LTSpice EDA was chosen as a modeling tool, which is distinguished by its versatility, ease of use and high reliability of results in comparison with similar software products. The modes of operation are analyzed depending on the requirements for the pulsation of the emitting matrix, the operation of the power factor corrector, and the suppression of interference into the industrial network from the operation of the source is estimated. Various options for the development of the circuitry implementation of the driver based on the LT3799 microcircuit and the operating modes of the most heavily loaded elements are analyzed: an inductor, a key transistor, a damper circuit, a diode in the power supply circuit of an LED matrix. Optimal values of circuit components and parameters of winding elements were selected. It is shown that due to the operation of the power factor corrector, the shape of the current consumption from a sinusoidal voltage source is also almost sinusoidal, which leads to an almost active nature of the load. The modes of operation of the LED matrix for the nominal supply voltage and for the reduced one (with a dimmer) are considered. Methods of implementation of a soft start of an LED matrix are described. Based on the results of the work, conclusions are drawn that summarize the expediency of using the developed driver for an LED device based on the LT3799 microcircuit.