Experience in Development of an On-Board Electric System Power Supply Based on Advanced Electronic Components

Abstract

The power supplies for an on-board electric system and auxiliary electric drives are considered taking the subway trains as an example. The development of semiconductor technology, in particular, devices made using silicon carbide (SiC), opens the possibility for designing a new generation of power supplies with improved technical and economic characteristics. The currently available SiC devices made both as modular units and as discrete chips are reviewed. In view of the high cost and limited range of modules, preference is given to discrete devices in the TO-247 package. Based on the results from estimating the losses in semiconductors and modeling their layout and thermal conditions, the optimal circuit solution for the stated problem has been determined. The effect the parameters of the power channel passive components have on the losses in semiconductor devices is evaluated. Based on the obtained evaluation results, the optimal inductances of the LC filters have been selected. The effect from introducing a time shift in the control of parallel-connected converters built according to the same scheme is analyzed. The effective values of the current through the output filter’s capacitors are quantified for the cases without the time shift in the control and with the shift by a quarter of the PWM cycle. The oscillograms of the power SiC transistor drain-source voltage transient obtained in testing the designed converter at the nominal load are presented. A description of the design of the converter’s container design is given along with a brief description of the layout solutions. An analysis of the mockup model test results and their comparison with the existing prototype have shown that the new power supply outperforms the prototype in having better efficiency and smaller weight and overall dimensions.