Multirate Analysis Method for a Power Electronic System by Circuit Partitioning

Various fast and efficient computation techniques for a power converter simulation have been researched. According to the conventional methods, a single step size for a whole circuit is selected for the numerical integration. A real-power electronic system, however, is multirate in that its currents and voltages nonuniformly vary spatially and temporally, and its subcircuits have different transient rates. A simulation that selected an appropriate step size for each subcircuit independently would, therefore, be more efficient. Several multirate analysis techniques have already been proposed; this paper proposes a new method that divides the whole circuit into subcircuits by applying an explicit integration formula to series inductors and/or parallel capacitors, and then integrates subcircuits by applying an implicit formula with independent integration step sizes. As analysis examples, this method is applied to an ac–dc converter, a benchmark test circuit, and a dc-link inverter control system. The proposed method’s effectiveness at reducing computational steps and CPU times is investigated, and its performance and efficiency are validated.