DC-Side Impedance Estimation of a Modular Multilevel Converter Through System Identification of a Partially Black-Boxed Control System

IEEE Transactions on Energy Conversion, vol. 37, pp. 2708–2721

Abstract

The stability of a power electronicssystem can be assessed by means of the impedance-based stability criterion. Impedance modeling is a useful tool to analyze the effect of different circuit parameters and control schemes on the behavior of a converter. Modeling the input impedance of a power electronics converter is often successful when having full knowledge of the converter topology, the circuit parameters, and the parameters and implementation of the control system. However, due to the proprietary nature of voltage source converter-based high voltage direct current systems, their exact control structure is often concealed. This complicates the calculation of the impedance of a modular multilevel converter, known for its complex internal dynamics. This paper proposes a method to estimate the impedance of a modular multilevel converter with partially black-boxed converter control. A discussion on partitioning the control system into open and closed parts is made, and the results are verified with simulations in time and frequency domains.

Authors 7

1. Mehrdad Nahalparvari

   KTH Royal Institute of Technology

   Affiliation as printed

   School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden

2. Mohsen Asoodar

   KTH Royal Institute of Technology

   Affiliation as printed

   School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden

3. Ilka Jahn Aachen Institute for Automation of Complex Power Systems E.ON Energy Research Center

   RWTH Aachen University

   Affiliation as printed

   Institute for Automation of Complex Power Systems, E.ON Energy Research Center, RWTH Aachen University, Aachen, Germany

4. Luca Bessegato

   Svenska kraftnät

   Affiliation as printed

   Department of Model Development and System Studies, Svenska Kraftnät, Sundbyberg, Sweden

5. Olivier Despouys
   Affiliation as printed

   Department of Research and Development, Réseau de Transport d’Électricité, Paris, France

6. Staffan Norrga

   KTH Royal Institute of Technology

   Affiliation as printed

   School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden

7. Hans‐Peter Nee

   KTH Royal Institute of Technology

   Affiliation as printed

   School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden