Depth analysis: LED in the end how dimmer (three)

Sudden drop: when dimming, the light source is turned off.

Dead zone: when changing the conduction angle of the dimmer, the light output does not follow the change.

Ghost: when the dimmer is completely closed, lights are still bright.

Noise

Twinkle

Blinking, dimming and color bleaching are the main reasons for experts and consumers to be cautious about solid state lighting. However, the lighting industry is to solve the dimming problem from all aspects. Last year's "NEMA SSL 7A-2013 solid state lighting for phase modulation: basic compatibility" attempts to develop a dimmer and LED product design and test criteria to minimize the problem of LED phase dimming compatibility. However, the standard is only for the future of technology, rather than trying to regulate the past dimming and lighting equipment.

Figure: in this case, the change rate of light output is a function of the dimming range. All of the above elements do not have to appear in the product configuration file. (solid state lighting systems and technology alliance)

The correct way to adjust light

Lighting industry has also developed an agreement to promote market unity. Ledotron is an open European digital standard, the purpose is to make those for compact fluorescent lamp CFL and LED light source design of the system can achieve stable dimming performance. This standard originated from several European manufacturers, including OSRAM and Schneider electric. In North America, ZigBee alliance ZigBee light link is the LED product to achieve wireless dimming and control standards. For the convenience of the consumer, with plug and play functionality and interoperability of lighting and lighting control products can be obtained by ZigBee to confirm the qualification of the Light Link certification.

Lighting research center (LRC) 2013 released "ASSIST recommended... Light: a technology neutral definition of" put forward regardless of the light source, the dimming performance standard should ensure that the end user's visual comfort and satisfaction. It sets the minimum and maximum light levels (5% and 90%, respectively) and the dimming evaluation file, and covers the problems of dead zone, flicker and system efficiency. In practical applications, LED dimming can minimize the problem by taking some precautions. First of all, the LED product designer should specify the dimming controller for the designed LED. Look for the combination of light source and dimmer for each LED product recommended by the manufacturer, or both. Installed inside the wall, Brodrick recommends the use of NEMA SSL-7A dimmer and LED light source.

The designer should be able to simulate all the dimming during the design process, "including all the LED light sources and dimmer, should be tested within the entire dimming range. "If the simulation is not implemented, it is necessary to provide a proof of the combination of the LED light source and the dimmer, and the proof information shall be guaranteed for no more than 6 months.

When the LED lamp dimming with the phase controller, the designer should switch to the maximum rated load of the optical device (usually expressed by Watt) derating, to minimize the pressure regulator. Although the LED is more efficient than the corresponding incandescent lamp, it is not possible to simply divide the number of LED lamps connected to a dimmer by the maximum rated load of the modulator. On the contrary, it is necessary to reduce the amount of use to adapt to spikes caused by the driver. "Typical derating percentages should be 25%~30% of the maximum rated load of the dimmer. "Ledzworld 's Kemeling said. If the maximum rated load of a dimmer is 1000W, the derating 250W should be used. This can be used to calculate the maximum number of light sources a dimmer can accommodate. Manufacturers are also working to improve the LED driver and dimmer circuits to achieve better compatibility with TRIAC, Narendran said. Some drivers have adaptive control functions, Kemeling said. This allows the LED to be compatible with any dimmer, but the cost is also increased. Therefore, in spite of the dimming technology in progress, but to achieve the best performance will take some time and effort.