Open AccessMulti‐scale transient modelling and simulation for distribution network‐interactive CHB multilevel converters
Author(s) -
Ye Hua,
Kong Li,
Tang Yanan,
Pei Wei,
Deng Wei
Publication year - 2020
Publication title -
iet generation, transmission and distribution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 110
eISSN - 1751-8695
pISSN - 1751-8687
DOI - 10.1049/iet-gtd.2019.0535
Subject(s) - converters , transient (computer programming) , scale (ratio) , computer science , electronic engineering , engineering , electrical engineering , voltage , physics , quantum mechanics , operating system
This study presents a multi‐scale transient model of cascaded H‐bridge (CHB) converter for distribution network‐interactive studies, which is capable of simulating slow‐changing dynamics up to high‐frequency switching transients. The switching pulse behaviours of H‐bridges are described using the waveform propagation theory. By taking individual H‐bridge sub‐modules into account, a semi‐analytic function (SAF) model of the CHB multilevel converter is developed. It allows for accelerated simulation of switch‐type electromagnetic transients (EMTs). During slow‐changing dynamics, the developed SAF is converted to a shifted‐frequency phasor (SFP) model using the Fourier series expansion. Due to the consistent modulation and complex analytical signal processes, smooth transitions between the SAF and SFP are achieved for different running stages. Moreover, the proposed model is readily integrated with external multi‐scale models of the distribution network. The validity of the proposed multi‐scale model is performed through case studies that include the CHB internal fault, distribution network faults, and also interactive dynamics between them. The accuracy and efficiency of the multi‐scale model is verified through comparisons of the results with those obtained from the full EMT‐type programmes.