Research on heat dissipation and cooling optimization of a power converter in natural convection

Authors: YANG XU, HAO CHEN, ZHENTAO HU, HUI ZENG, QIANLONG WANG

Abstract: A thermal model for the power converter in a switched reluctance motor drive under natural air cooling is presented. In this compact model, the modeling of the power device is simplified reasonably. Based on the computational fluid dynamics and finite element tools, the thermal and fluid characteristics of the power converter are obtained. The experiment platform is then established, which verifies the correctness of the simulation model. To increase the reliability of the power converter, the layouts of devices on the heat sink and the placement direction of the heat sink are optimized without changing the heat sink shape. Four cases of the device layout are designed and contrasted. Furthermore, the optimal layouts of the upper and lower rows of devices with different losses and different heat convection coefficients are derived by adopting a genetic algorithm. Three cases of the heat sink placement direction are designed and compared. Taking the maximum temperature rise and the temperature rise gradient as reliable indexes, the devices should be placed symmetrically on the heat sink if they have the same power losses. The heat sink should be placed horizontally with the fins opening up.

Keywords: Thermal model, power converter, natural convection, cooling optimization, switched reluctance motor

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