LED lighting industry lighting project, not only affected by the global environment, but also has its industry particularity.
1. Why must LED street lamp power supply be constant current?
The characteristics of LED lighting materials determine that LED is greatly affected by the environment. Constant current of LED is to ensure the constant value of its working current when the environmental factors such as temperature and voltage change.
2. Constant current accuracy of LED street lamp power supply
The constant current accuracy of some power supplies on the market is poor, generally required in ±3%. According to the design plan of 3%. Production power needs to be fine-tuned to achieve ±3% error.
3. Working voltage of LED street lamp power supply
The recommended working voltage of general leds is 3.0-3.5v. After testing, most of them work at 3.2v, so it is reasonable to use the calculation formula of 3.2v. The total voltage of N beads in series =3.2*N
4. What is the most appropriate working current of LED street lamp power supply?
After many comparative tests, the design of 320 milliamperes is ideal. Reduce heat as much as possible, so that more electrical energy into visible light energy.
5. How wide should the series and parallel connection and wide voltage of LED street lamp power panel be?
Try not to use wide voltage, can be divided into AC220V, AC110V classification as far as possible, so as to ensure the reliability of the power supply. As the current power supply is generally a non-isolated step-down constant current power supply, the output voltage shall not exceed 70V and the series number shall not exceed 23 when the voltage is required to be 110V. When the input voltage is 220V, the output voltage can reach 156V. That is, no more than 45 series. Do not have too many parallel connections, or the operating current will be too high and the power supply will generate serious heat.
Basically see dimensional structure to depend on specific case and decide, those who isolate can accomplish 15W only commonly, exceed 15W very few, and the price is very expensive. Therefore, the cost performance of isolation is not high, generally non-isolation accounts for more mainstream, volume can be done smaller, the minimum can be high 8 mm, in fact, the security measures are not isolated, there is no problem. Space can also do isolation power supply.
7. How can LED street lamp power supply match with lamp beads?
Choose one of the most excellent parallel connection mode, add voltage and current on each LED, power supply effect can play the best performance. The best way is to communicate with the power supplier first, and tailor it. Or produce your own power supply.
8. LED series and parallel connection and PFC power factor
Generally speaking, the isolated AC220V high-voltage end electrolytic capacitor capacity is input power 1W=1UF, and AC110V1W=2UF. Currently, there are three types of PFC power supply in the market:
One is the special circuit without PFC without power factor compensation, and its PF value is generally about 0.65.
Two is passive power factor compensation PFC circuit, that is, passive power factor compensation lamp, also known as the current circuit board is the most widely used the best reliability, PF value is generally around 0.92;
There are also three kinds of lighting engineering with active 7527/6561 circuit, that is, active power factor compensation.
9. LED street lamp power efficiency
The input power minus the output power value, the higher the value, the lower the efficiency, which means that a large part of the input power is converted into heat.
10. LED street lamp power dissipation
The main factor of heat dissipation scheme is that LED street lamp power beads can greatly extend the life under the condition of not overheating, generally using aluminum alloy, more easy to heat dissipation. In other words, LED street lamp power beads are pasted on the aluminum substrate to maximize the external heat dissipation area. In the face of such a broad LED market is full of vitality, mainly to scientific development, a few technical areas can get the leading position.