Power Supply device Thermal cooling solutions
During the operation of the power module, because the power consumption will occur inside the module and will be generated in the form of heat, if these heat are not radiated, it will accumulate inside the module, making the temperature too high, which may cause the power device to exceed the rated temperature limit; It may shorten the service life of the module power supply, or damage the module. Therefore, the heat dissipation design is very important for the power module.
In the absence of any thermal design of the system, it should be ensured that sufficient air flow channels are reserved at the top and bottom, so that when the module generates heat during operation, it will produce natural convection cooling with the ambient air due to the temperature difference.
When the air flow channel is imperfect and the module shell temperature is too high, the following methods can be used for heat dissipation design.
1. Add heatsinks:
The main function of the heat sink is to increase the contact area between the heat source and the ambient air. When there is appropriate air convection (including natural convection), it can significantly reduce the thermal resistance.
When the heat sink is directly connected with the shell of the power module, because the shell and the heat sink are made of hard materials and cannot ensure complete tightness and flatness, some gaps will be generated, which will increase the thermal resistance; Therefore, when assembling the heat sink, the power module needs to use thermal conductive surface materials, such as thermal compound and thermal pad, to ensure the close combination of the shell and the heat sink and reduce the gap.
2.Force air cooling:
Generally, a fan is used to generate forced air flow. Through the rapid flow of air, the thermal energy is taken away from the shell surface, which is to reduce the thermal resistance of the module .The effective method of Ca, especially in open modules, often uses this method to dissipate heat . The bigger the wind speed, the better the cooling effect; But do remember to pay attention to the wind direction to avoid being perpendicular to the module foot frame, which will reduce the heat dissipation effect.
If heat sink and forced air flow are used in the system at the same time, the matching mode of air flow and heat sink direction should be as shown in the figure below on the left, so as to obtain the best heat dissipation effect; The method shown in the figure below on the right is wrong. The air flow is not smooth and the heat dissipation effect is poor.
3. Power module connected to the shell:
For the system using the power module, if the system is designed with a metal shell or frame, the frame shell can be used as a heat sink to divert the thermal energy to the frame shell; If the surface of the frame shell is not very flat, a thicker or softer thermal conductive silica gel sheet can be selected if necessary to fill the joint gap to produce the best combination.
