Performance comparison of hybrid vehicle energy management controllers on real-world drive cycle data

Abstract

Abstract-Hybrid Vehicle fuel economy and drivability performance are very sensitive to the "Energy Management" controller that regulates power flow among the various energy sources and sinks. Many methods have been proposed for designing such controllers. Most analytical studies evaluate closed-loop performance on government test cycles. Moreover, there are few results that compare stochastic optimal control algorithms to the controllers employed in today's production hybrids. This paper studies controllers designed using Shortest Path Stochastic Dynamic Programming (SPSDP). The controllers are evaluated on Ford Motor Company's highly accurate proprietary vehicle model over large numbers of realworld drive cycles, and compared to a controller developed by Ford for a prototype vehicle. Results show the SPSDPbased controllers yield 2-3% better performance than the Ford controller on real-world driving data, with even more improvement on a government test cycle. In addition, the SPSDP-based controllers can directly quantify tradeoffs between fuel economy and drivability.

Fundamental Structural Limitations of an Industrial Energy Management Controller Architecture for Hybrid Vehicles

“…For this reason, the results are shown only for engine activity, although the controller design and implementation also includes gear selection as in [2,3].…”

“…Furthermore, it is difficult to compare controller architectures since it is very hard to assess whether or not a given calibration might be improved by judicious tuning [2].…”

“…This method is not the focus of this paper, merely a benchmark for comparison. The details of the algorithm are included as Appendix A as well as in previously published work [2,3].…”

“…The frontier of this point cloud is the Pareto tradeoff curve of maximum attainable performance; the HEV with this controller can be operated anywhere on that line, but not above it. A comparison is then made to the Pareto tradeoff curves of the SPSDP studied in [2,3].…”

“…The vehicle model and drivability metrics are summarized in Sections 2 and 3, respectively; these are similar to previous work in [2,3] and are included for the convenience of the reader. The architecture of the baseline industrial energy management controller and the tuning methods used are discussed in Section 4.…”