Comparison of DBI and ZSI supply for PM brushless DC drives powered by fuel cell

Nominal voltage of the traction motors being used in electric vehicles is typically higher than the voltage generated by the onboard DC sources. Thus, motors of AC type require boost as well as inversion of available DC voltage. This can be done either by a DC-DC boosted inverter (DBI) or by the recently introduced Z-source inverter (ZSI). Since drives with PM brushless DC (BLDC) motor are largely utilized in the traction of light electric vehicles, it is of interest to carry out a comparative analysis of the two supplies when feeding such kind of motor. In this paper, DBI and ZSI supplies are designed for the study case of an electric city scooter propelled by a PM BLDC motor and powered by a fuel cell with the assistance of a battery. Ratings of the transistors and sizes of the passive components for the two supplies are determined as a function of the fraction of the fuel cell power to the nominal power of the traction motor. The design results are discussed.