A5077240987- Microgrid Control and Optimization
- Islanding Detection in Power Systems
- Power Systems and Renewable Energy
- HVDC Systems and Fault Protection
- Advanced DC-DC Converters
- Smart Grid Energy Management
- Wind Turbine Control Systems
- Multilevel Inverters and Converters
- Autonomous Vehicle Technology and Safety
- Optimal Power Flow Distribution
- Reinforcement Learning in Robotics
- Photovoltaic System Optimization Techniques
- Human-Automation Interaction and Safety
- Robotic Path Planning Algorithms
- High-Voltage Power Transmission Systems
- Hybrid Renewable Energy Systems
- Frequency Control in Power Systems
- Smart Grid and Power Systems
Nanyang Technological University
2019-2024
Nomor Research (Germany)
2024
In more-electronics power systems, grid-forming converters, which operate as ac voltage sources, regulate the grid frequency and voltages in replacement of synchronous generators. Notably, impedances greatly influence small signal stability converters. As such, prior knowledge can be very helpful for controller design. However, impedance estimation schemes are normally designed current-controlled grid-following Moreover, they either complicated or only yield inductances a generally intrusive...
Grid-forming converters (GFMCs) provide voltage support and other grid services, such as inertia droop, in more-electronics power systems. The GFMCs with small droop coefficients or connected to the through a impedance may have fast loop, which leads serious conflicts inner ac control resulting oscillations even instability. To address this problem, an extremely loop should be expected for GFMCs. On top of that, must operate well both stand-alone grid-tied conditions. Through detailed...
The increasing penetration of renewable energy resources facilitates the carbon footprint reduction process yet reduces power system inertia. As a result, grid frequency and rate change (RoCoF) might probably go beyond normal range, resulting in unexpected load shedding, generator tripping, even instability. To address this problem, grid-connected inverters are designed to participate regulation provide equivalent inertial support. Nevertheless, inertia emulation effect is affected by...
Advances in the fields of renewable generation, electric vehicles, and energy storage systems push forward research on ac–dc dc–ac grid-tied power converters. However, variabilities converters create new challenges modeling control. Existing state-space models fail to accurately describe various types (GTCs), particularly those with grid-supportive services, which are increasingly required by upcoming grid codes. As such, this article first proposes classify GTCs into four basic according...
Distributed generations (DGs) have been increasingly employed in AC microgrids to provide carbon-free power supply. To coordinate multiple DGs, careful attention must be paid the synchronization stability of their interfaced inverters. Otherwise, low-frequency oscillations and even loss synchronism may occur pose a great threat system. The conventional solutions towards this issue are derive microgrid state-space model evaluate its based on roots characteristic equation. However, tremendous...
Grid-forming converters (GFMCs) prevail for their capability of providing voltage and frequency support in modern power grids with large integration intermittent distributed sources. As GFMCs behave as sources, the current limiting under disturbances requires special efforts. Furthermore, a reliable GFMC should also be capable remaining synchronized grid during after disturbances. To avoid instability caused by phase-locked loops low-voltage faults, usually retain active synchronization...
Driven by the demands of carbon footprint reduction, conventional fossil-based generators are gradually being replaced grid-forming inverter. One crucial aspect inverter is synchronization stability, which not only related to power-frequency (P-f) dynamic but also influenced power grid characteristics as well impedances. From perspective a local inverter, it difficult know detailed information. As result, severe oscillations and even loss may occur pose great threat grid. To overcome this...
Power-electronics-interfaced soft open points (SOPs) emerge as a promising solution for the fault-tolerant operation of distribution networks. The conventional SOPs interface two ac terminals with back-to-back (B2B) circuit configuration. Nevertheless, SOP will break down if fault occurs and interferes converter responsible dc-link voltage regulation. To address this problem, smart enhanced reliability is developed in article. proposed can protect system from fault, which at any terminals....
Grid synchronization stability is an important research topic for grid-forming converters. To prevent instability and undesired oscillations, the small-signal modeling analysis must be performed, which requires line impedance information. Nevertheless, may unknown in most cases. As a consequence, designed control parameters fail to satisfy requirement. fill this gap, article presents geometrical approach evaluate improve of The proposed analytical maps variation on two-dimensional plane...
Distributed virtual inertia provided by grid-friendly power converters is emerging as an effective way for enhancement and frequency regulation improvement in more-electronics systems. However, most existing methods attempt to generate distributed grid-following converters. As compared with conventional grid-feeding converters, grid-forming i.e. the ones controlled ac voltage sources, are more promising owing their capabilities of regulation. such, this paper explores possibility emulation...
The ever-increasing integration of power converter-coupled renewable energy sources reduces carbon footprints yet weakens system inertia due to the retirement synchronous generators. Inertia shortage makes modern systems sensitive frequency variations, thereby leading undesirable load shedding, cascading failures, or even large-scale blackouts. To address concern, distributed virtual from grid-tied converters is emerging as an attractive solution. On top that, there are upcoming standards...
The virtual synchronous generator (VSG) is emerging as a promising candidate for replacing generators in more-electronics power systems. Its fundamental objective lies the regulation of active and reactive voltage forming frequency control. To achieve tight regulation, VSGs usually have closed-loop controls. However, this paper reveals that coupling effect between control will greatly change stability VSG. Specifically, maximum transferred its associated angle are reduced because effect....
The growing penetration level of distributed generation (DG) requires power converters to be more grid-friendly. Driven by this demand, grid-forming have emerged as a promising solution for DG integration. Through proper control strategies, converter can emulate the synchronous generator and provide substantial frequency voltage support grid. Although normal operation has been well studied in existing works, controls under large disturbances such fault conditions not fully addressed yet. To...
To increase the reliability of distribution networks, back-to-back converters-based soft open points (SOPs) are emerging as supportive devices for flexible power dispatch and fault isolating under abnormal conditions. However, existing SOP control schemes characterized by a master-slave configuration, malfunction master converter will paralyze whole system. Further, SOPs controlled at current feeding mode, which cannot support isolated loads during islanding fault. In view these challenges,...
The ever-increasing penetration level of renewable energy sources (RESs) makes the future power system dominated by power-electronics devices. To support voltage and improve frequency regulation, grid-forming inverters are widely adopted. Recently, various active controllers (APCs) have been developed for inverter, such as droop control, synchronization control (PSC), virtual synchronous generator (VSG) control. Since APC establishes a relationship between phase angle, its design...
Reliability enhancement is always considered as the top priority of power distribution network. It highly expected that network faults can be locally addressed without spreading into entire grid. To fulfill requirement, this paper develops a smart power-electronics device named series soft open point (SSOP). The proposed SSOP connects two AC terminals and suppress surge current caused by short-circuit fault. In addition, it also performs grid-forming function during an islanding principle...
This paper analyzes the synchronization stability of grid-forming converter. The impact line impedance on small-signal is analyzed through Routh criterion. Moreover, stable and unstable regions are explicitly identified complex plane, providing clear insights into evaluation. Based analysis, a virtual inductance synthesized to guarantee without knowing information. effectiveness proposed approach verified by preliminary experimental results.
Grid-forming converters (GFMCs) are emerging as promising candidates in more-electronics power systems for their capabilities of forming voltage and frequency. Regarding the control GFMCs, lots research have been done on active reactive loop standalone source converters. However, little literature elaborates design current controllers when GFMCs connected to grid. This paper analyzes stability standard dual-inner-loop GFMCs. The requirements analyzed facts that limiting bandwidth identified....
Tracking objects in three-dimensional space is critical for autonomous driving. To ensure safety while driving, the tracker must be able to reliably track across frames and accurately estimate their states such as velocity acceleration present. Existing works frequently focus on association task either neglecting model performance state estimation or deploying complex heuristics predict states. In this paper, we propose STT, a Stateful built with Transformers, that can consistently scenes...
The low-voltage-ride-through (LVRT) of grid-forming converters (GFMCs) requires that GFMCs can limit current and remain synchronized with grids under post severe voltage sags. To avoid the instability caused by phase-locked loops during limiting processes, usually retain active-power angle synchronization (P-Syn) algorithm low faults when saturation is triggered. When sags happen, virtual power stability highly depends on durations levels P-syn method. This paper analyzes LVRT mechanism...
The limit inertia contribution from renewable energy sources develops into a challenge to small-scale power systems. For the purpose of allaying negative influence on frequency regulation performance, concept virtual control used in three-phase grid-connected converters has been proposed. system improvement could be realized by linking grid and voltage reference DC-link capacitors/ultracapacitors. This paper intends reveal that effects delay, which are caused measurements during emulation,...