Sinrace Power Supply Technology (Shenzhen) Co., Ltd.

      The design technology of cooing communication switching power supply (SMPS)firstly should meet all kinds of technical feature requirements of the industry. To better adapt the special circumstances of use of the environment in the communications rooms, requiring the cooling of the ambient temperature adaptability. Rectifier current cooling methods are commonly used in natural cooling, pure fan cooling, natural cooling and fan cooling the combination of three. Natural cooling with no mechanical failure, high reliability; no air flow, dust less conducive to heat; no noise and so on. Pure fan cooling with light weight and low cost. The combination of fan and natural cooling techniques have effectively reduced equipment size and weight of the high life of the fan, fan failure adaptive capacity and other characteristics.

    1, natural cooling

     Natural cooling is the switching power supply in the early stage cooling method, this approach relies mainly on the large metal heat sink to direct heat conduction cooling. Heat transfer Q = KA △ t (K heat transfer coefficient, A heat transfer area, △ t temperature difference). When the rectifier output power increases, the power components of the temperature rise, △ t temperature difference also increased, so when the rectifier when sufficient heat transfer area A, the heat is no time lag, the small temperature difference between the power components, the thermal stress and small heat shock. But the main drawback of this approach is that a large heat sink size and weight. Transformer winding temperature is as low as possible to prevent the rise in temperature affect their work performance, so the margin of its large choice of materials, transformer size and weight is also large. Rectifier material costs are high, maintenance or replacement is not convenient. Because of its less demanding on the cleanliness of the environment, the current power supply for small-capacity communication, in some there are some small professional communication network applications, such as electricity, petroleum, broadcasting, military, water, national security and public security.

    2, fan cooling

     With the development of manufacturing fan technology ,the job stability and service life of fans have a greater progress, the average time without failures is 50,000 hours.

 After using less bulky cooling fan radiator, making the converter volume and weight greatly improved, raw material costs are reduced. With the market competition, market prices decline, this technology has become a major trend. 

 The main disadvantage of this approach is the fan MTBF 100,000 hours over Rectifier short time after the power supply fan failure if the failure rate of major. Therefore, to ensure the life of the fan, the fan speed is temperature inside with the device varies. The heat dissipation Q = Km △ t (K heat transfer coefficient, m heat air quality, △ t temperature difference). m heat exchanger and fan air quality is speed related, when the rectifier output power increases, the power components of the temperature rise, temperature change to the power rectifier device can detect this change, to increase the fan speed to enhance the heat dissipation, in time, there is a big lag. If the load is frequently mutated or fluctuating mains input, will result in hot and cold power components showed rapid changes in temperature difference between the mutation of the semiconductor thermal stress and thermal shock will lead to component parts of different materials cause stress cracks. So that premature failure.

    3, the combination of fan and natural cooling

    Due to environmental temperature changes and load changes, the power dissipation of heat when working, the use of fans and natural cooling will be faster in the combination of heat dissipation out. In this way, while the increase in cooling fan, radiator area can be reduced, making the power components work in a relatively stable temperature conditions, life will not be affected by external conditions change. This will not only overcome the power of pure component fan cooling on the shortcomings of thermal accommodative lag, but also to avoid the fan service life of low-impact the overall reliability of the rectifier. In particular, the temperature in the room is very unstable environment, using a combination of cold air and self-cooling technology has better cooling performance. In this way the cost of materials rectifier pure and natural cooling fan to cool between the two methods, low weight and easy maintenance.

    Especially in the use of smart air-cooled and self-cooling technology that allows rectifier at low load operating conditions, the module temperature rise is small, the fan at low speed state of the module. In high-load operating conditions, the module temperature. Module temperature rising over 55 ℃. Changes in fan speed increases linearly with temperature. The reign of fan failure detection, fan failure, fan failure limiting output, fault alarm. As several fans running related to the size and load, making the life of the fan when the air is longer than that of pure, whose reliability is greatly increased.

    Communication switching power supply using a combination fan and natural cooling of the cooling method, both in the case of high ambient temperature, effectively reduce the temperature inside the rectifier to extend the life of the device, but also lower the ambient temperature and load in the case of low , the rectifier reduces the fan speed work, to extend the life of the fan. With radiator heat, the device spacing and creepage distances can be relatively far away, in the case of high humidity, high safety. Rectifier are smaller, lighter, making maintenance easier.

    Communication SMPS to ensure reliable and stable operation of the rectifier to reduce the temperature of their work is a key technology. Since the cold air and a smart combination of technologies. Has on the environment and adaptable, long life, reliable and other technical advantages