Abstract
Electrification of heavy-duty trucks is of great interest since it would bring substantial benefits in terms of emissions (>80% of road transport) and noise. This study investigates energy-optimized torque allocation for an all-wheel-drive electric truck. The novel approach formulates the variable operating temperature of the Electric Motor (EM) to reduce power consumption, recognizing that the EM temperature changes in response to variable loads and speeds. A high-fidelity multi-physical model of the permanent magnet synchronous machine is developed and used. Such an approach allows the analysis of electric, magnetic, mechanical, and thermal effects, including their cross-influence. The EMs characteristics are updated as a function of temperature. Therefore, the novel strategy is capable of optimally distributing torque between axles based on the temperature to minimize energy consumption. It is compared with two commonly used techniques: The fixed torque ratio distribution and the fixed-temperature optimum torque allocation strategy. The first set of results has proven that varying-temperature-based optimal torque allocation strategy reduces power consumption by up to 2% and 3% for ESK (Eskisehir) cycle for the aforementioned techniques. Further analysis has indicated that these figures can increase to 3% and 7%, demonstrating the drive cycle's decisive effect.