The need for minimization of (fossil) fuel consumption and local emissions in personal transportation has led to a significant interest in drive train electrification. This trend is not limited to the hybridization or complete electrification of the motor itself but also extends to major auxiliaries either due to the lack of an internal combustion engine in all-electric vehicles or in order to further improve fuel efficiency.
With all components connected to a central dc-link with voltages of several hundred volts, the interaction of all kinds of different loads attracts significant attention during development of an electric powertrain. Detailed simulation models of the complete drive train are used in order to assess powertrain efficiency, driving performance as well as voltages levels and current flows for different driving conditions. Such simulations models subsequently focus on dynamics in the range of seconds (e.g. longitudinal dynamics) or even minutes (e.g. battery state of charge).
However, such simulation models do not account for high frequency variations of voltages and currents which result from the virtually instantaneous switching of load currents in power electronics, such as the drive inverter or DC/DC converters. As such variations might interference with component controllers, cause additional losses and therefore require extensive filtering, a priori analysis of high frequency harmonics becomes increasingly important.
This project aims to set up an experimentally validated simulation model of a complex electric drive train focusing on dynamics in the frequency range from 100 Hz up to several dozens of kilohertz. This includes the mathematical modelling of voltage and current ripples caused by switching in power electronics depending on the chosen modulation schemes and drive train configuration. Based on the simulation model, the relevance of high frequency harmonics in terms of additional losses and filter requirements will be analyzed.
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