Design Current Capacity Through Copper Bar

With the rapid development of electronic technology, large power electronic products increasingly become the most concern in analysis and design of. Copper bar as a large current conducting product, is widely used in electrical equipment and power system, copper tends to have large current through, which will bring great temperature rise, temperature rise exceeds a certain value will lead to accelerated ageing and even malfunction, causing huge economic losses. Copper bar in the application have changeable and flexible installation, there is a need for temperature distribution analysis of copper bar in different conditions. In addition, with the development of science, a lot of energy product design presents demand of direct contact with copper and copper, copper and PCB, the current through the contact can constrain the development of power electronic devices. Therefore research on influence of copper and copper, copper and PCB contact on the through current capacity is also very necessary, which makes the power electronic device has higher performance in general, has certain significance to adapt to different engineering applications better.In this paper, firstly analysis the single uprightly placed copper bar, using thermal analysis theory to calculate the steady state situation of copper bar, convection coefficient are calculated in detail. Then using ANSYS finite element software analyse temperature distribution under a variety of installation coating and bending conditions, which reflect the heat dissipation capability under different conditions. Through the analysis showed that copper cooling is associated with heat dissipation area and ways of placement, only considering the heat dissipation area sometimes cannot reach the best effect. The best effect is uprightly placed, with large heat dissipation area and small size of cooling surface feature, conducive to good heat dissipation, the temperature is76.26degrees. Stand placed on the contrary, the dissipation surface is small and the main cooling surface feature is the largest size, cooling effect is the worst, the temperature is130.09degrees. For copper bolt connection, without considering the bolt effect the temperature is76.64degrees, considering the bolt effect, due to the close connection, the contact resistance is small, bolts and other exposed parts increase the dissipation surface, the temperature is75.38degrees. If the connection is not up to requirements, due to the increase of contact resistance, will cause a sharp temperature increase in the contact area, which may lead to failure. For copper bar in contact with PCB, due to the presence of copper foil, make up for the PCB poor conduction ability, the overall temperature difference at about10degrees, the highest temperature is in the contact zone,75.53degrees. In addition, the smaller overlap length of copper bar and PCB is conducive to reduce the maximum temperature and reduce the overall temperature difference.For copper in contact with PCB, because of the thermal conductivity of PCB material has great effect for the overall temperature distribution and improve the condition of the heat convection is a commonly used method for thermal design of electronic equipment. Therefore propose two optimization scheme, improving PCB materials and the convection environment. Discovered that the addition of heat conduction layer can make the thermal effect obviously improved, make the overall temperature difference decreased, but the effect of heat conduction layer is not more obvious when more thick, increase the heat conduction layer thickness is limited to further reduce the overall temperature. In addition, changing the natural convection into forced ventilation cooling indeed has a great improvement; but continue to increase the intensity of ventilation is not obvious for the improvement.