Forward-Looking Simulation of the GM Front-Wheel Drive Two-Mode Power-Split HEV Using a Dynamic Programming-Informed Equivalent Cost Minimization Strategy

This paper presents a forward-looking simulation (FLS) approach for the front wheel drive (FWD) General Motors Allison Hybrid System II (GM AHS-II). The supervisory control approach is based on a dynamic programming-informed Equivalent Cost Minimization Strategy (ECMS). The controller development uses backward-looking simulations (BLS), which execute quickly by neglecting component transients while assuming exact adherence to a specified drive cycle. Since ECMS sometimes prescribes control strategies with rapid component transients, its efficacy remains unknown until these transients are modeled. This is addressed by porting the ECMS controller to a forward-looking simulation where component transients are modeled in high fidelity. Techniques of implementing the ECMS controller and commanding the various power plants in the GM AHS-II for FLS are discussed. It is shown that FLS-derived component states agree well with states commanded using the BLS-derived robust control strategy, with any difference being accounted for by transient effects. Fuel economy results from FLS decrease, as to be expected, by approximately 3-7% from that of BLS due to the increase in propulsion energy required by component transients. Overall, these two points of good agreement demonstrate the viability of the DP-informed ECMS as an online-implementable supervisory control strategy.