Study on ZnO-based electric field adaptively controlled structure in power electronic module

Nonlinear composite (NC) shows promising prospect on addressing the problem of local electric field concentration in power electronic modules. In this paper, ZnO microvaristors/silicone rubber (SiR) composite is prepared to construct the electric field adaptively controlled structure in power electronic module. The influence of two factors, the nonlinear parameters of the NC and the length of the structure, on the electric field distribution has been studied by simulation. It is found that the electric field concentrates at the edge of the upper copper layer to the silicone gel, the triple junctions of metal-ceramic-silicone gel of the upper and lower copper layers and the triple junction of metal-base plant-silicone gel. When the electric field adaptively controlled structure is applied, the points of electric field concentration move from the end of the copper layer to the end of NC and the highest electric field intensities of the points decrease significantly. It shows the best electric field controlling effect when the nonlinear conductivity of the NC is S1 and length of the electric field adaptively controlled structure is 2.0 mm. The electric field intensities of the points can be limited below 10 kV/mm.