【 Weak current College 】 dimming system efficiency and heat issues

Summary: dimming equipment is an important part of the television equipment. Dimming system's power tend to be very large, this produces a thermal problems. Physical cooling is usually considered first, and dimming system efficiency is closely linked with this. With specific digital description dimming system efficiency of thermal problems, and provides the kind of solution.

In recent years, various audio and video equipment to spring up like mushrooms, but TV dimming system development is relative lag, transposes the optical system is especially important.
The art of light, is television. Dimming system's safety and reliability, is to use light to create a powerful guarantee the objective world. Any professional use of lighting control system, its power is great, a single light bulb is 5kW, 10kW even one show available thousands of bulbs. This shows that a dimming system's total electricity consumption is amazing. Therefore, dimming system efficiency and cooling is very important, it is a dimming system long operation remains the key to its reliability.
Lighting control equipment has undergone four generations: the first generation as resistance-type dimmer. The second generation of the transformer-type lighting control equipment. The third generation is the electromagnetic amplifier-lighting control equipment. The fourth generation is SCR dimmer devices. The first generation of efficiency, the fourth generation of the most efficient.
If dimming system efficiency is not high, itself consumes power is impressive. Assuming that its efficiency is 96% (it seems is already a very good figures), when it should promote a 6kW of load, with its own power is:
6×（１００％－９６％）=0.24kW
Suppose a dimming standing Cabinet 60 6kW of load, this time, it's up to the total power consumption is:
0.２４×６０＝１４.４kW
Therefore, improving the efficiency of dimming system is very important. It not only reduce the dimming standing cabinet temperature (because temperature and power consumption is proportional to), but also reduces power consumption, thereby reducing operational costs. At present, more advanced dimming system incorporates the latest solid state switch and efficient choke, its efficiency up to 98 percent, reduced due to non-100% dimming the current rapid increase in the maximum interference. (SCR is by changing the angle to adjust voltage, it only about the breakover time 1 μ s, this current waveform is actually a frontier steep pulse. ）
However, even if it is a very efficient dimming system, cooling system performance and design is still very important. Even 98% efficiency to the above as an example, their power is still as high as $ 7.2kW. To make such a big power consumption effectively to the system, keeping the system internal components at a reasonable temperature environment, rational design of cooling systems to be ignored.
At present, the world's popular standing cabinet cooling systems are 3: forced air, forced ventilation and smart ventilation.
(1) forced ventilation
This cooling system is a fan installed on the bottom of a Cabinet, allows fresh air to enter from the bottom of the Cabinet after accelerated to blow away the thyristor, thereby producing heat.

This approach has the advantage of high efficiency, with a small fan that can left a lot of tropical. Its disadvantage is that the pumping from below into the cold air flowing in to constantly be on the way of power consumption heating controlled rectifier, Silicon-controlled temperature is at the top of the bottom of the much higher, resulting in top of SCR reliability and life span.
(2) forced ventilation
This system is to exhaust fan installed on the top of the Cabinet. Through an appropriate process design allows fresh air from the front of each SCR, and then through the exhaust the hot air to the Cabinet.
This approach through precision design (fluid dynamics) and strict process control, can be done from the top to the bottom of each SCR into air volume are roughly the same, so you can make each SCR are within an acceptable temperature range operation, ensuring the reliability of each SCR. But this design also has the disadvantage of wind resistance is large, need to increase the fan's power and noise are large.
(3) Intelligent ventilation
Because in the General case, dimming system rarely is loaded so that the required amount of ventilation can be reduced correspondingly. Smart ventilation is according to this theory, through detection of temperature rise within the Cabinet and then decided convulsion, under normal operating circumstances fan just low-speed operation, relative to reduce noise, but when the load increases, the fan will speed up accordingly. This preserves the advantages of forced ventilation, also addresses the shortcomings of high noise.
Finally it is worth mentioning, although there is a high efficiency of dimming and good heat emission system, but dimming system is always a great electric power system. High temperature and the arc striking phenomenon cannot be completely avoided. Only in the high efficiency and good heat dissipation, supplemented by the necessary high-temperature resistant and fire prevention measures (such as the use of high-temperature flame line) in order to ensure that the entire dimming system safe to use.