Abstract: One miniature low frequency power cabinet was overheated, and the thermal can not be transmitted effectively from the heat sink in one new project. Considering this situation, this paper makes a complete thermal simulation analysis on the heating parts such as the IGBT modules, electrical source and drive power modules. The layout of the electrical components is optimized, and the heat sink module is improved, to maintain the cabinet element under the connect point temperature. The experiments on the prototype conformed that the heat simulation results are correct and the device optimization is achieved.