Tips to protect LED street light drivers from damage
There are two current driving methods for LED street lights: one is a constant voltage source used for multiple constant current sources, and each constant current source provides power for each LED. In this way, the combination is very flexible, and the failure of one LED will not affect the work of other LEDs. LEDs operate in series or parallel. The advantage is that the cost is slightly lower, but the flexibility is poor, and the problem of one LED failure must be solved without affecting the work of other LEDs. These two forms coexist for a period of time.
In terms of cost and performance, the multi-channel constant current output power supply mode will be better. Maybe it will become the mainstream direction in the future. Although the power factor of a single low-power user is low, it has little impact on the grid, but the amount of lighting used at night is too large, and similar loads are too concentrated, which will cause serious pollution to the grid.
For 30 to 40 watt LED drive power supplies, it is said that in the near future, power factor may have certain index requirements. How to protect the LED street light driver to avoid damage (1) When the LED street light driver is installed in a non-ventilated environment, please try to make the driver housing contact the lamp housing, and coat the contact surface between it and the lamp housing with thermal glue or Thermal pad to improve the heat dissipation performance of the drive and ensure the life and reliability of the drive.
(2) The power of each lamp will still vary greatly. However, the volt-ampere characteristics of the LED determine that the LED driver is a constant current source, and its output voltage varies with the change in the series voltage Vo of the LED load. When formulating requirements, you should first understand the working characteristics of LED lighting street lights, avoid putting forward some indicators that do not meet the principle of working characteristics, and at the same time avoid indicators that far exceed actual requirements, and avoid excess quality and cost waste.
(3) The ability of LEDs to resist surges is relatively poor, and it is also important to strengthen the protection in this area. Some LED lights are installed outdoors, such as LED street lights. Due to the initiation of the grid load and the induction of lightning strikes, various surges will be invaded from the grid system, and some surges will cause damage to the LED.
(4) Intelligent control is one of the advantages of LED lamps. Intelligent control can realize stepless control of lamp power at different time periods and according to road traffic density. It not only meets application requirements, but also achieves huge energy-saving effects. Save a lot of money for highway supervisory units. The application of tunnel lighting can not only save energy.
(5) If the driver is broken, disassemble the LED street lamp head and check the internal radiator, LED chip and power supply drive. Damage to the radiator will cause the LED street lamp head to have too high heat, burn out the internal circuit, and make it not light. . Of course, a better solution to this situation is to return it to the street lamp manufacturer and ask them to provide a new LED street lamp head.
(6) Protective performance. Sand and dust on the shell will affect the heat dissipation of the power supply, and exposure to the sun will easily cause high temperature and aging of wires and other components. From the practical experience, the failure rate of rotary wiring plugs is relatively high. Failure due to water leakage.
(7) A self-recovery fuse is selected for the power supply of the LED driver. Self-recovery fuse, also known as polymer positive temperature thermistor PTC, is composed of polymer and conductive particles. The PTC resettable fuse is in a low resistance state. When an abnormal overcurrent occurs in the circuit (or when the ambient temperature rises),
The heat generated by the large current will cause the polymer to expand rapidly, thereby cutting off the conductive path formed by the conductive particles. Under normal working conditions, the self-recovery fuse generates very little heat. Under abnormal working conditions, its heat is very high and the resistance value is large, which limits the current flowing through it, thereby protecting the LED drive power supply.