Dynamic Switching Frequency and Advanced Modulation for Automotive Applications - An investigation of efficiency optimization in electric drive lines

Abstract

Abstract The rapid electrification of the vehicle fleets around the world has heavily increased the demand for high efficiency powertrains. The development of this requires thorough evaluation methods for all steps in the power transmission process. One part that can be optimized to increase efficiency is varying the switching frequency in the inverter. Using more complex Pulse Width Modulation (PWM) principles could also be a way to increase efficiency. In this project, the impact on the electric drive systems efficiency with regard to inverter switching frequency and modulation principle were examined. Also, a simulation model of a real drive system was developed in Matlab, Simulink and JMAG. This model was used to evaluate power losses for different operating conditions of the drive system. The model’s results were compared to tests conducted on a physical drive line. The study showed that a dynamic switching frequency is more power efficient than a fixed one. In terms of PWM principle, the most effective was Space Vector Pulse Width Modulation (SVPWM) for all tested operating conditions. The simulation model’s results had a mean difference of 3.5 %-points from the real physical tests.