大功率平面变压器温度场模拟及热失效分析

Temperature Field Simulation and Thermal Failure Analysis of High Power Planar-transformers

针对一种大功率平面变压器,建立了有限元模型,计算得到了稳态温度场,确定了辐射、传导等边界条件以及组件结构参数对温度场的影响,分析了印制电路板内短路和分层导致的热失效。结果表明,热失效敏感点位于多层印制板芯部区域靠近磁芯的铜布线附近,磁芯和散热板对变压器散热起主要作用,而辐射对保证印制板元器件热可靠性具有重要意义,磁芯与散热板接触面积对变压器温度影响不明显。热失效敏感区铜布线短路或印制板内出现两处以上分层都将引起热失效。

The finite-element model is built to calculate the steady-state temperature field of a high power planar-transformer. Some factors affecting the temperature field has been studied, such as thermal radiation, conduction boundary and other structure parameters. Moreover, the thermal failure due to the PCB inner wiring shot-circuiting and delaminating is also studied. It shows that the thermal failure sensitive district is the PCB copper wirings near the magnetic core. The magnetic core, cooling plate and thermal radiation are essential to the heat dissipation of transformer. The contact area between magnetic core and cooling plate has little effect on the heat dissipation. The short-circuit of copper-wiring and more than two PCB inner-layer delaminating in the thermal failure sensitive district will lead to the thermal failure of the transformer.