Phase-Trajectory Region Criterion and Quantitative Optimization Method for Numerical Stability in Power Electronic Simulation

Numerical simulation-based digitalization has aroused great research interests recently in power electronic design. As the basic but most important problem, numerical stability is sensitive to the accumulation of numerical errors, which becomes a new challenge with the high-frequency application in power electronic simulation due to the switching features and discontinuous events. In this article, the factors affecting the numerical stability are systematically analyzed. Then, the phase-trajectory region criterion is proposed to simplify the judgement process of numerical stability based on dominant influence factors, as a result, the limitations of discontinuous event handling and low efficiency in traditional criteria can be basically covered. Besides, an optimization method based on first-order numerical integration is proposed to quantitatively modify the stability region and improve the numerical stability. Finally, the validation results in offline and real-time environment are demonstrated to confirm the validity of proposed criterion and optimized rule for the stability risks obtainment and oscillation suppression, respectively.