دانلود کتاب مدل سازی و شبیه سازی مبدل چند سطحی مدولار برای سیستم های HVDC

Modular multilevel converters (mmcs) have evolved as the technology of choice in high voltage direct current (hvdc) systems, which nowadays are increasingly adopted to connect asynchronous ac grids and efficiently transmit power over large distances. The distinctive feature of the mmc is the presence of a stack of up to several hundreds of identical submodules (sms) in each of its arms. On the one hand, this modular structure grants the mmc reduced switching losses and scalability to high voltage and power ratings, thus making it a popular technology in hvdc systems. On the other hand, the mmc topology and its complex control scheme pose several challenges in standard power system simulators tasks. One of these challenges, namely the electromagnetic transient (emt) simulation of mmcs, is the core topic of this book. In essence, the multitude of cascaded sms in each arm implies that many electrical nodes (unknowns) and semiconductor devices must be evaluated simultaneously while simulating. Thus, simulations of mmc-based hvdc systems lead to a high computational burden if conventional emt simulation tools and mmc models are adopted. To reduce cpu times, scholars proposed several mmc models that rely on simpler sm representations and implement different trade-offs between simulation speed and accuracy. Despite successfully reducing the computational burden, these models are incompatible with thorough mmc-based ac/dc network simulations,which may require a detailed transistor-level representation of the semiconductor devices in the sms. In this framework, the purpose of this book is twofold. First, it provides a comprehensive review and comparison of the mmc models developed in the literature over the years. Second, it proposes a novel and efficient mmc simulation approach based on sub-circuit isomorphism. This technique, which has its roots in the field of electronics, can be profitably exploited to efficiently simulate mmcs regardless of the model used to describe its sms, including the most accurate ones.