| The good heat dissipation condition can guarantee the safe and reliable operation of power converter in the electric vehicle. Therefore, the optimization design of cooling for the electronic components on the converter is one of the hotspots to be focused on. The core of power device on the power converter is IGBT. The power loss of IGBT will lead to temperature rising. If the cooling condition is poor, the temperature rising will be out of range of the allowed temperature which not only reduce the efficiency of power converter but also influence the travel distance of electric cars. However, at present, the consideration is less and saving energy and reducing consumption is not considered in the method of traditional optimization design for the cooling system of power converter. So it is limited to improve the thermal stability and reliability of power converter in the electric vehicle. Aiming to above problems, the optimization design of the cooling system is carried out based on the thermomechanical analysis in this thesis. To improve the thermal stability and reliability of the electric vehicle power converter, the simulation research of fluid-solid conjugated based on the study of the thermal analysis is taken to further optimize the design of the Cooling system of Power Converters in the Electric Cars.First of all, the composition structure and working principle of power converter are depicted. Secondly, under the condition of the driving and regenerative braking of the electric car, the current that passes through the IGBT on the power converter is tested. It is continuous triangular waveform current. With the related formula and the Triangle wave current through the IGBT on the power converter, the heat loss of IGBT is calculated. Thirdly, the fluid and solid coupling problem of the heat transfer for IGBT is explored based on the finite element software ANSYS Workbench, and the thermal simulation analysis is taken respectively by being aimed at a single heat dissipation fin radiator, the distance between two heat dissipation fins, the number of cooling fins, the different distance between two IGBTs, the structure size of the radiator, and so on. Afterward, the best design parameters are chosen based on the optimization design of multi-objective parameter by ANSYS Workbench/Design Exploration analysis module. The forced air cooling is chosen and the best power fan is suited by computing the power of the fan. Finally, the heat source condition of IGBT is imported in the ANSYS Workbench/UDF module and the optimized cooling system is simulated on-line. The temperature distribution is got with the continuous changing of heat source over time in the cooling system. It is verified in this thesis that the optimized design scheme is feasible,effective and the purpose of saving energy and reducing consumption is achieved. In addition,the research also paved for the optimization design of the thermal managing system of the power converter for the electric vehicle. |
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