The design of high-frequency switching power supply cooling technology is designed to meet the technical performance requirements of the industry. In order to adapt to the environment of the special environment of the communication room, the cooling method is required to adapt to the change of the ambient temperature. At present, the commonly used rectifier cooling methods are natural cooling, pure fan cooling, natural cooling and fan cooling. Natural cooling has no mechanical failures, high reliability; no air flow, less dust, good heat dissipation; no noise, etc., pure fan cooling, light weight and low cost. The combination of fan and natural cooling is effective in reducing the size and weight of the equipment. The fan has a long life and strong adaptability.
1. Natural cooling
The natural cooling method is a traditional high-frequency switching power supply cooling method, which mainly relies on a large metal radiator for direct heat conduction and heat dissipation. Heat Q = KA t (K heat transfer coefficient, heat exchange area, t temperature difference). When the rectified output power increases, the temperature difference of the power device will increase, so when the rectified heat exchange area is sufficient, the heat dissipation will not lag, and the temperature difference power device will be smaller, its thermal stress and thermal shock. But the main disadvantage of this method is the volume and weight of the radiator. The transformer winding is to reduce the temperature as much as possible to prevent the temperature rise from affecting its working performance, so the selection of materials is large, and the volume and weight of the transformer are also large. The material cost of the rectifier is very high, so maintenance and replacement are inconvenient. Due to its low environmental cleanliness requirements, current communication power supplies are used in small-capacity, professional communication networks and some applications in electric power, petroleum, radio and television, military, water conservancy, national security, public security and other applications.
2. Fan cooling
With the development of fan manufacturing technology, the working stability and service life of the fan have been greatly improved, and the average time to failure is 50,000 hours.
The cooling of the fan can reduce the larger radiator, greatly increase the volume and weight of the rectifier, and greatly reduce the cost of raw materials. With the intensification of market competition and the decline of market prices, this technology has become the main current trend.
3. Combination of fan and natural cooling
Due to changes in ambient temperature and load changes, the power supply energy consumes heat dissipation, and the combination of fans and natural cooling methods can release heat faster. In this way, the cooling fan is increased and the area of the radiator can also be reduced, so that the power unit works in a relatively stable temperature field, and the service life does not change due to changes in external conditions. This not only overcomes the shortcomings of pure fan-cooled power element cooling, but also avoids the overall reliability of the service life of the fan. Especially when the temperature of the machine room is very unstable, the combination of cooling technology, air cooling and self cooling has better cooling performance. In this way, the material cost of the rectifier is between pure fan cooling and natural cooling, low weight, and convenient maintenance.