Optimal Operating Strategy for Hybrid Railway Vehicles based on a Sensitivity Analysis

Comparative Calculation of the Fuel–Optimal Operating Strategy for Diesel Hybrid Railway Vehicles

“…Ott et al, 2012), and the use of several cycle-averaged efficiencies for each energy conversion step as in the work of Katrasnik et al (2007) can be found in the literature. Leska et al (2014) analyse the energy conversion using a complete simulation model of a hybrid railway vehicle with a mechanical transmission and an on-board lithium-ion battery including the main system components of the power train.…”

“…In this paper, the approach of Leska et al (2014) is adapted for a hybrid railway vehicle with a diesel-electric transmission with a battery (Bat) and a double layer capacitor (DLC), respectively, as an on-board energy storage system (ESS). In Section 2, a control-oriented simulation model is derived for both railway vehicles.…”

“…Then, the fuel-optimal operating strategy is calculated in two alternative ways: in Section 4.1 by dynamic programming according to Bellman, and in Section 4.2 by a sensitivity-based optimisation (cf. Leska et al, 2014). Both the methods are compared with each other in Section 5 regarding accuracy, computational effort and the ability for an on-line energy management.…”

Fuel-optimal combined driving strategy and energy management for a parallel hybrid electric railway vehicle

“…This strategy depends on the actual value and the progression of the state of charge σ (t) of the battery. The power split ratio δ ∈ [−1, 1] is introduced as control input according to [5], [7]. It reflects the distribution of the requested power P d as follows: a positive threshold δ > 0 represents a support of the ICE by the M/G (Mode 3) up to the maximum value of δ = 1.…”

“…Numerical methods assume a known driving cycle to determine the optimal control numerically; dynamic programming, cf. [7] and [8], and genetic algorithms [9] belong to this category. Analytical optimisation approaches also employ a parametrised speed profile, where the optimal solution is calculated symbolically.…”