Development of high power and energy efficient electric drivetrain for electromobility: Energy analysis

The electrification of the transport sector is a key strategy to reduce CO2 emissions and limit global warming. In this context, the electric two-wheelers play a crucial role in urban mobility, especially in countries like India and China. This thesis investigates the use of a variable flux permanent magnet motor (VFM) in the drivetrain of an electric two-wheeler, proving its superior performance compared to a commercial motor (CM). The VFM motor allows flux regulation through changes in the air gap configuration, enabling a wider and more efficient torque-speed operating range. The electric two-wheeler is simulated using a Simulink model to determine the motor’s operating conditions across various drive cycles. The motor torque and speed data extracted from the simulations are further elaborated and then interpolated with the efficiency maps for the performance analysis. The study evaluates the efficiency of the VFM motor, characterized by multiple maps, by determining the theoretical maximum efficiency achievable and analyzing energy consumption with and without regenerative braking. The results show that the VFM motor is at least 6% more efficient and consumes 11% less energy than the CM. The highest efficiency of 91% is reached in JC08 and WLTP3 cycles, reflecting the suitability of the VFM for city traffic. Furthermore, the VFM motor offers significant energy savings through regenerative braking, particularly in cycles with frequent and rapid decelerations, such as SG1, where up to 48% of energy can be ideally recovered.