A heuristic supervisory controller for a 48V hybrid electric vehicle considering fuel economy and battery aging 2019-01-0079
The most of the studies on supervisory controllers of hybrid electric vehicles consider only the fuel economy in the objective function. Taking into consideration the importance of the health of the energy storage system and its impact on functionality, cost, and warranty of the vehicles, recent studies have included battery degradation as the second objective function by proposing different energy management strategies and battery life estimation methods. In this paper, a heuristic supervisory controller is proposed that splits the torque demand based not only on fuel consumption, but also on the battery capacity fade using the concept of severity factor. For this aim, the severity factor is calculated at each time step of a drive cycle using a look-up table with three different inputs including c-rate, working temperature, and state of the charge of the battery. The capacity loss of the battery is then calculated using a semi-empirical capacity fade model. Eventually, the fuel economy, and capacity loss as two of the most important objectives are compared with and without implementing the proposed controller. In the comparative study, four customized drive cycles are considered, including calm/aggressive drivers and low/high vehicle speeds. The results suggest considerable improvement in the objectives and trade-off between fuel economy and battery aging. The proposed controller can be used and implemented for different types of hybrid electric vehicles.
Hybrid Electric Vehicle, Rule-based Supervisory Controller, Energy Management Strategy, Fuel Economy, Battery Aging
Farzam Malmir, Bin Xu, Zoran Filipi
International Powertrains, Fuels & Lubricants Meeting