Abstract: As an important device of mine ventilation system,the heat emission performance of mine frequency converter will affect the safety production of coal mine. The current mine frequency converter requires higher power to volume ratio,which is conducive to underground installation and commissioning. In order to solve the above problems, an embedded air - cooled frequency converter structure based on local ventilator was proposed. By using the working air flow of fan,the frequency converter was cooled by forced air cooling. Based on the conventional fin,the isosceles triangle and arc fin were designed,and the threedimensional modeling and junction temperature theoretical calculation were carried out respectively, and the finite element method was used to simulate the three models. The temperature field and vector field of IGBT module were analyzed. The results show that the error between numerical simulation and theoretical calculation is within 5%; the smaller the fin spacing is,the more serious the air flow loss is,and the problem of flow loss under isosceles triangular and circular fins is better solved;The fin spacing of circular fins is small,but the heat emission performance is improved by increasing the convective heat transfer area between the fins and the fluid. The optimal arc-shaped fins have the best heat emission performance when the fin spacing is constant,the fin height and thickness are 105 mm and 5 mm respectively.