How to choose LED power supply
LED lighting products are not unfamiliar to everyone, and energy saving and environmental protection are closely related to LED power supplies. Let's take a look at the parameters of the LED drive power supply!
1. Output type: It can be divided into two types: constant voltage and constant current. But the constant voltage source cannot be used directly on the LED lamps, it can be used only by adding a constant current module between the power supply and the lamps.
Some LED street lamp manufacturers on the market are using the "constant voltage source + constant current module" solution. This design stems from solving the problem of uneven current distribution among parallel circuits of high-power LED lamps.
In the practical application of circuit design, the solution of more series and less parallel can solve the problem of uneven current distribution. At the same time, the direct use of a constant current source reduces the possible problems of the whole set of lamps, and also saves manufacturing and subsequent maintenance costs.
2. Constant current accuracy: refers to the amplitude of current fluctuation when the power supply is working.
Constant current accuracy has different requirements in different industries. In terms of LED lamp power supply, it should generally be controlled within 5% (Landt reaches 3%) in order to reduce the impact of current on LED light attenuation. This is also the difference between LED power supply and others. One of the key differences in power supply.
3. Surge current: refers to the peak current flowing into the power supply equipment at the moment the power is turned on. Since the input filter capacitor is quickly charged, the peak current is much greater than the steady-state input current.
To solve the surge problem, we should start with the level of surge that the power AC switch, rectifier bridge, fuse, and EMI filter components can withstand. This is also a necessary consideration for our power supply and other LED power supply manufacturers.
4. Conversion efficiency: refers to the ratio of the output power of the power supply to the input power.
The application of LED lamps is for energy saving and environmental protection. If the conversion efficiency of electric energy to light energy is not high, it will lose the meaning of use. Of course, in addition to the conversion efficiency of the power supply from electric energy to light energy, the conversion efficiency of the lamp is also determined. However, the power conversion efficiency of 85% and 90% has faded out of the historical stage, and higher conversion efficiency of constant current sources has emerged. (Although Guangdong Province requires the power conversion efficiency to reach 88% in the LED street lamp standard implemented on July 1st)
5. Power factor: the ratio of actual power to apparent power.
In the AC system, part of the AC current circulates in the load without transmitting electric energy. It is called reactance current or harmonic current, which makes the apparent power (voltage Volt multiplied by current Amps) greater than the actual power. Represents the ability of the power supply to output active power. Therefore, the minimum requirement in LED street lamp power supply is 0.90, but it can be reached by a large number of manufacturers that currently reach 0.95.
6. Leakage current: The reverse current flowing in the diode when the diode is applied with a reverse voltage.
The LED leakage current is used as the quality criterion for the resistance to electrostatic breakdown of the LED. Of course, the smaller the current, the better. Generally, the leakage current is very small, less than milliampere level, and the maximum is 10μA, which is about 30nA. The power supply of LED street light can be controlled at 0.2ma-0.4ma.
LED lighting is not just a product, but a system and a productivity. Its scientific, safe and economical industrial lighting can not only meet the special environmental requirements of industrial production, but also reduce energy consumption. Moreover, a comfortable visual environment can reduce the visual fatigue rate, error rate, and even the probability of accidents of workers, improve production efficiency, and ultimately achieve the goals of energy saving, value-added, and efficiency for enterprises, and enhance corporate social responsibility.
