Driving simulation of a parallel hybrid electric vehicle using receding horizon control

Fuel-consumption and catalyst-out emissions of a parallel HEV (hybrid electric vehicle) are affected by operating region of an engine. It is generally known that it is profitable in fuel-consumption to operate engine in OOL (optimal operating line). We established the mathematical model of a parallel HEV, which is linear time-invariant. To operate an engine in OOL, we applied RHC (receding horizon control), because it has the advantages such as good tracking performance under the state and control constraints. This RHC is obtained by using the semi-definite programming in the LMI (linear matrix inequality) form. In this paper, there are two main topics. First, under state and control constraints by the engine and motor performances, the optimal tracking of OOL was simulated. Second, we combined the RHC with the iterative simulation to extract the optimal gear ratio. In this simulation, the vehicle is commanded to track the reference vehicle trajectory, and the engine is operated in the optimal operating region which is made by the state constraints.