Nested fast and simultaneous solution for time-domain simulation of integrative power-electric and electronic systems

As power electronics are increasingly used in power-electric networks, there is an interest in the creation of time-domain simulation techniques that can model the diversity of the integrative power-electric and electronic system while achieving high accuracy and computational speed. In the proposed method, generation of electric network equivalents (GENE), this is supported through the nested structure of the overall simulation process. One or multiple parent simulations, in which the unknown voltages are calculated using nodal analysis, launch multiple child simulations concerned with diakoptic subdivisions of the system under study. The interfaces for information exchange between parent and child levels are designed to provide encapsulation. This makes the subdivisions appearing from outside in the form of network branches compatible with the nodal analysis approach. It also facilitates the use of diverse solution methods for different child simulations, as it is shown for the simultaneous solution of equations formulated with nodal analysis and state space methods. Computational efficiency is obtained through the coordinated application of sparse-matrix methods, piecewise linear approximation of nonlinear characteristics, and precalculation of operations pertaining to recurring power-electronic switch statuses. The resulting overall solution process is simultaneous, distributed, and suitable for real-time simulation. The devised methodology is validated through simulation of the CIGRE HVdc benchmark model, comprising ac networks, twelve-pulse power-electronic converter stations, harmonic filters, and dc transmission.