Energy Conservation and Coupling Error Reduction in Non-Iterative Co-Simulations

TL;DR

This paper improves non-iterative co-simulation accuracy and stability by modifying energy-preserving coupling methods and combining them with adaptive step size control, significantly reducing coupling errors in benchmark models.

Contribution

It introduces a modification to NEPCE for direct feed-through scenarios and demonstrates enhanced accuracy by combining NEPCE with ECCO's adaptive control.

Findings

Coupling errors reduced by up to 98% in benchmark tests.

Combining NEPCE with ECCO improves simulation accuracy and efficiency.

Modified NEPCE effectively handles direct feed-through in co-simulations.

Abstract

When simulators are energetically coupled in a co-simulation, residual energies alter the total energy of the full coupled system. This distorts the system dynamics, lowers the quality of the results, and can lead to instability. By using power bonds to realize simulator coupling, the Energy-Conservation-based Co-Simulation method (ECCO) [Sadjina et al. 2016] exploits these concepts to define non-iterative global error estimation and adaptive step size control relying on coupling variable data alone. Following similar argumentation, the Nearly Energy Preserving Coupling Element (NEPCE) [Benedikt et al. 2013] uses corrections to the simulator inputs to approximately ensure energy conservation. Here, we discuss a modification to NEPCE for when direct feed-through is present in one of the coupled simulators. We further demonstrate how accuracy and efficiency in non-iterative co-simulations are substantially enhanced when combining NEPCE with ECCO's adaptive step size controller. A quarter car model with linear and nonlinear damping characteristics serves as a co-simulation benchmark, and we observe reductions of the coupling errors of up to 98% utilizing the concepts discussed here.