Sequence Impedance Characteristics of Grid-Forming Converter Controls

authored by: Marc Dokus, Axel Mertens
Abstract: In this paper, the sequence impedance-based small-signal modelling is exemplarily applied to the synchronverter control approach with three different inner control setups and compared against other popular grid-forming concepts, namely droop control and the virtual synchronous generator (VSG). The synchronverter variations differ in terms of whether an inner dual loop voltage control (DLVC), a single loop voltage control (SLVC) or an open loop voltage control (OLVC) concept is utilised. These models are derived in a common sequence impedance framework which is a suitable approach to analyse the robustness of different converter controls in a generalised form. First, impedance models are derived, which do not only reveal the existence of a mirrored frequency as an image of the disturbance frequency shifted by two times the fundamental frequency, but also predict the effect of the different grid-forming control variations on the system stability. These models are evaluated against other control methods and validated by time-domain simulations and experimental results. The applicability of the models is confirmed by a close correlation between sequence impedance model, time-domain simulations, experimental results as well as based on a case study.
Organisation(s): Institute of Drive Systems and Power Electronics
Type: Conference contribution
Pages: 413-420
No. of pages: 8
Publication date: 2020
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Energy Engineering and Power Technology, Renewable Energy, Sustainability and the Environment, Electrical and Electronic Engineering, Control and Optimization
Sustainable Development Goals: SDG 7 - Affordable and Clean Energy
Electronic version(s): https://doi.org/10.1109/PEDG48541.2020.9244356 (Access: Closed)