Analysis of the potential performance of a combined hybrid vehicle with optimal supervisory control

The paper presents an optimization analysis of the supervision control strategies of a combined hybrid propulsion system, realized via a direct (i.e., without a planetary gear set) mechanical link between the shaft of the internal combustion engine and the shaft of the traction electric motor. The analysis is based on a quasistatic mathematical model of the overall system that is derived in a pure analytical fashion, using the Willans approach, in order to help the synthesis of the control laws. The latter are calculated using Pontryagin´s Minimum Principle and the Euler-Lagrange equations of the optimal control theory. Simulation tests performed over a hybridized mass-production van show the potential of the combined-hybrid architecture, in terms of fuel economy, in comparison to the conventional (engine-only), the series-hybrid, and the parallel-hybrid architectures.