A Hierarchical Multiarea Hybrid Equivalent for Efficient Simulation of Scalable Power Electronics Systems

This article proposes a hierarchical multiarea hybrid equivalent circuit partitioning framework for electromagnetic transient simulations of large-scale power electronics systems in the time domain. The concepts of linking partition and hierarchical partition tree are introduced to organize this partitioning process. The multiarea hybrid equivalent (MAHE) is applied hierarchically across multiple levels of the partition tree, leveraging the linear additivity of impedance in series and admittance in parallel. This method solves series currents and parallel voltages layer by layer, transferring Thévenin and Norton equivalents from lower to upper ports to mitigate the increase in linking variables connecting circuit partitions. The proposed hourglass scheduling model also optimizes the execution order by grouping independent partitions in batches, enhancing parallelism. Simulation models for a two-terminal modular multilevel converter based high voltage direct current transmission system and a photovoltaic power station are developed and compared with other commercial simulation software in terms of accuracy and efficiency. The hierarchical MAHE scheme demonstrates equivalent accuracy while offering superior efficiency.