Heat dissipation of power devices

In the voltage-stabilized power supply, the main components are power semiconductor devices, such as power transistors (GTR), power field-effect transistors (MOSFET), insulated gate bipolar transistors (IGBT), etc. The most important thing when using these components is how to effectively dissipate the generated heat to obtain high reliability of their operation. The most common method of heat dissipation is to install the components on a radiator, which radiates the heat to the surrounding environment to dissipate the heat through natural convection.

Generally speaking, the heat flux P from the heat sink to the surrounding environment is

Where, h is the total thermal conductivity of the radiator [W/(cm2.℃)], which is determined by radiation and convection; A is the surface area of ​​the radiator (cm2); η is the radiator efficiency, which is determined by the shape of the radiator; ΔT is the difference between the maximum temperature of the radiator and the ambient temperature (℃).

From formula (5-12), we can see that the larger the surface area of ​​the radiator, the greater the difference between the surface area and the ambient temperature, and the more effective the heat radiation of the radiator.