Isomorphism-based simulation of modular multilevel converters

This chapter shows how the isomorphism-based approach can be applied to perform efficient EMT simulations of MMCs. This approach has three main features, which have been validated by adopting it to simulate a benchmark system comprising two MMCs. First, the approach is compatible with any MMC operating condition (ranging from ordinary operation to faults in the AC and DC networks) and SM model. Indeed, depending on the degree of detail required, the user can flexibly choose the complex FP, the simple BVR representation, or even a brand new custom SC representation. Second, regardless of the SM model adopted, the CPU time required to simulate MMCs increases only almost linearly with the number of SMS in each MMC arm. Lastly, the proposed simulation approach paves the way for component level studies that require the adoption of the FP model of SMS . This kind of analysis would be possible with neither conventional simulation approaches nor the MMC representations outlined in Section 6.2. Indeed, in the former case, the adoption of the FP representation would lead to prohibitive simulation times. On the contrary, in the latter case, the use of accelerated MMC models prevents the analysis of switching transients within the SMS either because they adopt too simplified SM models or they do not retain their individual behavior.