Influence of cooling mode on working temperature of switching power supply
The heat dissipation of switching power supply generally adopts two ways: direct conduction and convection conduction. Direct heat conduction is the transfer of heat energy from the high temperature end to the low temperature end along the object, and its heat conduction ability is stable. Convective conduction is a process in which the temperature of liquid or gas tends to be uniform through rotary motion. Because convection conduction involves dynamic process, the cooling rate is relatively smooth.
When the hair element is installed on the metal radiator, energy can be transferred by energy bodies with different heights by squeezing the hot surface, and there is not much energy that can be radiated by large-area heat sinks. This heat conduction mode of switching power supply is called natural cooling, which has a long delay time for heat dissipation. The heat exchange quantity Q=KA△t(K heat exchange coefficient, A heat exchange area, △t temperature difference), if the indoor ambient temperature is high, the * * * of △t will be small, and then the heat dissipation performance of this heat transfer method will be greatly reduced.
Adding a fan to the switching power supply can quickly discharge the heat accumulated in energy conversion out of the power supply. The continuous air supply from the fan to the heat sink can be regarded as convective energy transfer. Called fan cooling, this cooling method has a short delay time. Heat dissipation Q=Km△t(K heat exchange coefficient, m heat exchange air quality, △t temperature difference), once the speed of the fan decreases or stops, the value of m will decrease rapidly, and the heat accumulated in the power supply will be difficult to dissipate, which will greatly increase the aging speed of electronic components such as capacitors and transformers in the switching power supply, affect the stability of its output quality, and eventually lead to component burning and equipment failure.
