Main electronic design of power electronics

- Sep 21, 2018-

(1) Resistor. The temperature of the resistor is related to its form, size, power consumption, installation position and mode, and ambient temperature. It is generally radiated by its own radiation, convection, and metal heat conduction at both ends of the lead wire. Under normal ambient temperature, it is known through experiments. The carbon film resistance of less than 0.5W, the heat dissipated by conduction accounts for 50%, the convection heat dissipation accounts for 40%, and the radiation heat dissipation accounts for 10%. Therefore, when assembling the resistor, make the lead wire as short as possible to reduce the thermal resistance. The installation method should be such that the surface with large heat generation is perpendicular to the path of the convective gas and the distance between other components is increased. In order to increase the convection heat dissipation effect, the surface of the resistor is coated with a matt rough paint to improve the radiation heat dissipation capability.

(2) Transformer. The iron core and the wire package are the heat source of the transformer, and the conduction is the main heat transfer path inside. Therefore, the iron core and the bracket are required, and the bracket and the fixing surface are carefully processed to ensure good contact, so that the thermal resistance is minimized, and at the same time on the bottom plate. Ventilation holes should be opened to make the airflow convective, and the surface of the transformer should be coated with a matt black paint to enhance the radiation dissipation.