Analysis and comparison of soft-transition inverters

This paper presents a comparative analysis of a set of soft-transition techniques applied in inverters utilizing IGBT as power switches. The techniques are compared based in losses, number of components, stresses and type of commutation obtained. An estimation of power losses and junction temperature of insulated gate bipolar transistor (IGBT) devices is used to compare the soft-transition techniques. The method used to estimate the losses and temperatures is based in the data obtained from the devices data sheets and in the governing equation of the auxiliary circuits. This method uses a program written in MATLAB, which make use of an iterative process to obtain the convergence of the values of losses and temperature. Experimental results of the soft-transition techniques are presented, as well as a discussion about their characteristics.