Determination of the power losses due to the nonlinear coss capacitance of SJ MOSFETs submitted to voltage transients in ZVS applications

摘要

Effects of the parasitic capacitance Coss of MOSFET devices on soft-switching converters are investigated, especially in terms of power losses, considering that the influence of the nonlinearity of this parameter has been proved. An experimental workbench, which allow measuring the frequency and voltage dependence of the parasitic capacitance, has been realized. A comparison of different super junction devices in soft-switching converters is performed. Since the power losses related to the MOSFET output impedance are highly dependent on the application, a class-E resonant converter has been firstly designed, and then realized aiming to detect the power losses for this application. As forthcoming work, it could be useful to define a figure of merit for comparing different devices in soft-switching operations.