Requirements for film capacitors used in LED lighting products

There are many types of LED lighting products, such as bulbs, fluorescent lamps, industrial lamps, street lamps, etc. Some products have small space and high temperature, so the required capacitors are also small in size, high in temperature resistance, and good in current and voltage resistance.

LED products have small internal space and slow heat dissipation. Long-term use will cause temperature build-up. Small-capacity and high-temperature-resistant film capacitors are required. However, the average film capacitor on the market has a temperature resistance of 85 °C, which may not be too high. The dielectric film shrinks and deforms, resulting in a change in capacitor capacity and a decrease in voltage and current resistance. Therefore, a film capacitor of 110 ° C material is selected, and the film capacitor has an ultimate temperature resistance of 120 ° C.

Generally, LED lighting lamps on the roadside, lighting lamps in factories, etc. should be energized for a long time in 24 hours, and due to structural reasons, the film capacitors will have a certain degree of attenuation for a long time, especially in the case of RC. . The main reason is that when the film is wound, the gap between the film and the film generates ozone inside during long-term energization, and the metal layer is oxidized after accumulation to cause a decrease in capacity. Therefore, in the production of capacitors, it is necessary to reduce the internal voids by high-temperature hot pressing, improve the sealing performance of the capacitors, and use plastic enamel to encapsulate the products.

The common polyester film capacitor on the market has a high self-loss, and the temperature rise can reach above 10 °C. If it is used for AC for a long time, it is easy to generate heat breakdown, and the polypropylene capacitor is 10 times smaller than the polyester film capacitor. Low rise, high impact strength, good pressure resistance under high frequency AC conditions, so try to use polypropylene capacitors.