Autonomous DC-link voltage restoration for grid-connected power converters providing virtual inertia

• Main Authors: Guo, Ke, Fang, Jingyang, Tang, Yi
• Other Authors: School of Electrical and Electronic Engineering
• Format: Conference or Workshop Item
• Language: English
• Published: 2020
• Subjects: Engineering::Electrical and electronic engineering; Capacitor; Filter
• Online Access: https://hdl.handle.net/10356/144525
• Institution: Nanyang Technological University

Renewable energy sources have been increasingly adopted to reduce greenhouse emissions. However, they are normally interfaced with power grids through grid-connected power converters without any inertia contribution. This will lead to the decreased power system inertia. As a solution, the method of inertia emulation by power converters has been reported to handle this problem. However, the DC-link capacitors of power converters cannot restore their voltages after injecting the power required by inertia emulation. Thus, if the load change causes another DC-link voltage drop, the undesirable overmodulation may appear. Moreover, power converters cannot provide multiple inertia support during cascading frequency events without the DC-link voltage recovery. To address the above concerns, this paper proposes an autonomous DC-link voltage restoration method that allows the restoration of DC-link voltages after individual frequency events. Simulation and experimental results verify the feasibility of the proposed method.