Speeding Up AC Circuit Co-Simulations Through Selective Simulator Decoupling of Predictable States

Co-simulation has become increasingly popular as a tool for dealing with the unprecedented complexity of modern engineering systems, such as electrical power systems and the AC circuits that compose them. Co-simulation is useful when migrating the models of each subsystem to a single monolithic simulator is either impractical or impossible, and the need for understanding the interactions between the subsystems does not leave room for model simplifications. However, co-simulation can suffer from long execution times, caused by the overhead introduced by exchanging variables between simulators. In this paper, we propose a method that mitigates this overhead by decoupling the simulators whenever their inputs become predictable. We applied this method to the co-simulation of an AC circuit composed of two subsystems and obtained speedups of up to 39% with errors that remain around 1% most of the time. Although questions regarding the scalability of the method persist, these results indicate that the method has the potential to make co-simulation an even more valuable tool for the user.