A Supervisory Power-Splitting Approach for a New Ultracapacitor–Battery Vehicle Deploying Two Propulsion Machines

Electrification of performance vehicles brings several challenges, such as the necessity of high-power sources, which can satisfy the power requirements during acceleration and efficiently retrieve energy during deceleration without performance and life cycle deterioration of such sources. In addition, the limited space under the hood for these vehicles eliminates the possibility of utilizing large volume high-power propulsion machines. This paper proposes a fuzzy logic supervisory wavelet-transform frequency decoupling-based energy management strategy implemented on a new powertrain deploying two propulsion machines rated at different powers with a hybrid battery/ultracapacitor (UC) energy storage system (ESS). The proposed control and energy management strategy guarantees that battery and UC provide the base and transient-free powers, respectively, while state of charge (SOC) of UC is maintained at an optimal value. The torque demand is split among the propulsion machines by solving the formulated unconstrained optimization problem. With the proposed hybrid ESS and energy/power decoupling strategy, power density of the ESS can be increased, vehicle performance can be improved, and battery lifetime can be prolonged.