The Influence of Cooling Methods on the Operating Temperature of Switching Power Supplies
The heat dissipation of switching power supplies generally adopts two methods: direct conduction and convective conduction. Direct heat conduction refers to the transfer of heat energy along an object from the high temperature end to the low temperature end, and its heat conduction ability is stable. Convective conduction is the process in which a liquid or gas undergoes a rotational motion to equalize its temperature. Due to the involvement of convective conduction in the dynamic process, the cooling process is relatively smooth.
Install the generator on a metal heat sink, and by squeezing the hot surface, achieve energy transfer between high and low energy bodies. The energy that can be radiated by a large area of heat sink is not much. This type of heat conduction in switching power supplies is called natural cooling, which has a longer delay time for heat dissipation. Heat transfer Q=KA △ t (K heat transfer coefficient, A heat transfer area, △ t temperature difference). If the indoor ambient temperature is too high, the value of △ t will be small, and the heat dissipation performance of this heat transfer method will greatly decrease.
Adding a fan to a switching power supply quickly removes the heat accumulated during energy conversion from the power supply. The continuous supply of air by the fan to the heat sink can be considered as convective energy transfer. It is called fan cooling, and this cooling method has a short and long delay time. Heat dissipation Q=Km △ t (K heat transfer coefficient, m heat exchange air quality, △ t temperature difference). Once the fan speed decreases or stops running, the m value will quickly decrease, and the heat accumulated in the power supply will be difficult to dissipate. This will greatly increase the aging rate of electronic components such as capacitors and transformers in the switching power supply and affect the stability of their output quality, ultimately leading to component burning and equipment failure.
