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Because the surrounding environment has a greater impac […]
Because the surrounding environment has a greater impact on the heat dissipation effect of LED street lights, such as the increase of temperature in summer, the current of LED street lights will increase, and the voltage will increase. If the rated current is exceeded for a long time, the service life of LED street lights will be greatly shortened. LED constant current is to ensure that its operating current value remains unchanged when environmental factors such as temperature and voltage change. Therefore, this problem can be solved. The effect of the radiator LED street lamp power supply, power supply constant current accuracy LED street lamp market, some power supplies have poor constant current accuracy, popular LED street lamps on the market recommend other solutions, the error is up to ±8%, constant current error is too big. The overall requirement is ±3%. According to the 3% design plan. The power of the production department should be fine-tuned to ±3% error.
Power supply voltage of LED street lamp.
The working voltage of the light-emitting diode is 3.0~3.5V. After testing, most of the working voltage is 3.2V, so it is more reasonable to calculate by 3.2V. n The total voltage of the lamp beads in series = 3.2*N, the working current of the LED street lamp power supply is the most suitable, for example, the rated working current of the LED is 350 mA. Some factories ran out at the beginning and designed 350 mA. Actually It is very serious to work under this current. After many comparison tests, the ideal design is 320 mA. Minimize heat generation, so that more electrical energy becomes visible light energy.
Ordinary isolated power supply such as 15W, placed in the LED street light power tube, the transformer is very large, difficult to place. Mainly depends on the space structure and depends on the specific situation. Generally, the isolation area can only reach 15W. After 15W, it is very rare and very expensive. Therefore, the cost performance of isolators is not high. Generally, non-isolators dominate the mainstream. The volume can be made smaller, and the smallest can be made up to 8 mm. In fact, if the isolator has taken safety measures, there is no problem. The permitted space can also be used as isolated power supply.
How can LED street lamp power supply match the lamp bead board? Some customers design the lamp board first, and then find the power supply. It is difficult to have a suitable power supply, either the current is too large or the voltage is too small (such as 7X1WI>350mA, or <20V); Either the current is too small, the voltage is too high (such as I<200mA, V>25V), resulting in serious heating, low efficiency, or insufficient input voltage range. In fact, choose the best series-parallel connection method, the voltage and current of each LED are the same, but the effect of the power supply can play the best performance. It is best to communicate with the power supply manufacturer first and customize it according to their requirements. Or make your own electricity.
Series-parallel connection and power factor of light-emitting diodes.
It is advisable to connect the LED street lamp power supply in series with no more than 45 strings of lamp beads. Therefore, in order to obtain a larger power coefficient, the number of series connection of the lamp beads cannot be too small, otherwise the best working condition cannot be achieved. The number of series connection on the isolated power supply is related to the number of turns of the secondary winding, and the required power supply must be Meet the requirements of output power.
The smaller the working current of the electronic device under the rated voltage, the longer the life of the bottom, and the shorter the life of the bottom. Lamp beads are more sensitive to the inductance of LED street lights. The higher the AC inductance, the worse the lighting comfort.
Electrolytic capacitors are generally used to maintain the voltage, try to reduce the AC voltage at the output terminal, and the capacity of the bottom voltage terminal electrolytic capacitor should not be too small. The ratio of the capacity of 1UF<1.5MA to the output current, otherwise the LED will flicker. The non-isolated input end of the high-voltage electrolytic capacitor is the same as the isolated type, and the output end is 1UF<6MA. The output electrolytic capacitor of the dimming LED power supply is 1UF<0.5MA.
LED power supply efficiency of lighting fixtures.
Especially important is the value of input power minus output power. The larger this parameter, the lower the efficiency, which means that a large part of the input power is converted into heat. Therefore, efficiency is the most basic factor that determines the life of the power supply. The efficiency cannot be too low, otherwise it will consume too much energy. The efficiency of the non-isolated type is higher than that of the isolated type, generally above 80%. However, the efficiency of the isolated type is related to the mating method of the light board.