Comparison of 2-level B6C and 3-level NPC inverter topologies for electric vehicles

Due to strict emission regulations the electrification of the whole car fleet becomes more and more important resulting in an increased demand for higher powertrain performance and faster dc-charging. One possibility is to increase the dc-link voltage of the electric vehicles. Thus, multi-level inverter topologies are examined considering their suitability for these electric vehicles and compared to standard 2-level inverters. A simulation model to calculate the losses of the inverter was set up, the results were fed into the electric vehicle simulation and used to investigate the efficiency for different driving cycles. In order to validate the simulation results, two inverters were developed using an at most similar design. Furthermore, the fault tolerance was investigated and compared. It could be shown that for new developments in electric vehicles such as high speed electric machines or higher power demand the multi-level topology can be beneficial compared to the standard 2-level topology.