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With the rapid development of LED technology, in many domestic cities, road lighting has no shortage of LED street lights. Especially after the luminous efficiency of high-power LED devices exceeds 100lm / W, the development trend of LED street lamps as road lighting has been generally recognized.
In 2009, several cities in China organized the evaluation and testing of LED road lighting products. Most LED street light products have made significant progress in key technical indicators such as light distribution curve and system light efficiency. The effect and other aspects have reached the requirements of relevant standards and specifications.
Although the technical level of LED street lamps has developed rapidly, most LED street lamp manufacturers have ignored the special technical requirements in cold areas during product development. A common misconception is that the application of LEDs in cold areas is conducive to heat dissipation and is not prone to failure. As everyone knows, under the cold application environment, there are stricter technical requirements for LED street lights, mainly in the following two aspects:
The main reason for the above problems is that the device selection of the drive power supply in the design stage does not consider the reliability of the low-temperature working state, and the characteristics of some key components under low-temperature environment have changed, resulting in the failure of the low-temperature startup or normal operation of the drive device, causing failure The specific reasons are as follows:
(1) The density and activity of the switching tube under low temperature conditions will be reduced, and the starting point of overload protection will be reduced accordingly.
(2) The electrolytic solution of the electrolytic capacitor freezes at a low temperature, and loses the capacitive effect (the ions in the solution only have ion polarization at this time), and has no loading capacity.
(3) Some types of optical coupling devices cannot work normally at low temperatures.
(4) The thermistor that prevents surge current at the input end becomes larger at low temperature (3 to 5 times the normal temperature), which also causes the low temperature to fail to start normally.
