Block Diagonal Dominance-Based Model Reduction Method Applied to MMC Asymmetric Stability Analysis

Frequency-domain model reduction is a crucial concern in applying the prevailing impedance method for stability analysis of complex systems, e.g., modular multilevel converter (MMC). Recently, it has been shown that under symmetric conditions, 2 × matrix-based characterizing two coupled frequencies MMC are sufficient its analysis. However, when asymmetry occurs, principally, much higher number frequency couplings will appear and thereby leads to significant rise dimension. Enlighted by this issue, there an urgent need finding suitable frequency-domain can serve as general criterion reduction. To end, article proposes block diagonal dominance (BDD)-based applied asymmetric MMC. Basically, BDD decompose N-dimensional task N one-dimensional tasks, via which dimension be realized. It properly shifting from one domain another (e.g., ?-? d-q domain), property achieved most scenarios. Finally, various case studies considering different degrees conducted validate effectiveness proposed method.