Microgrids rely on both primary and secondary frequency control techniques to maintain system stability. Secondary effectively minimizes fluctuations by adjusting the active power reference in each inverter, but requires complex costly interequipment communication. In this paper, we propose a distributed strategy for microgrids containing multiple virtual synchronous generator (VSG) units based new maximum loading factor (MPLF) concept. The MPLF algorithm facilitates sharing dynamically...

Paralleled grid-forming converters (GFMs) system suffers from transient instability issues while accurate model is complicated and unsuitable to give stability analysis. Existing aggregation method requires either extensive computation or linearized assumption realize coherent identification, which might not distinguish unstable units stable clusters. In this paper, a two-step algorithm proposed recognition for multi-GFMs based on Lyapunov energy function: 1) GFMs are distinguished clusters...

This article discusses control techniques of the current-controlled and voltage-controlled BICs in a hybrid ac/dc microgrid. We draw following conclusions: 1) The BIC is simple easy to deploy. It decouple its active reactive power has few circulation problems. However, it highly relies on ac bus voltage support often poor operating characteristics weak grid. 2) usually own reference can operate with or without side bars. also depends little PLLs. Therefore, from perspective system stability,...

Poor power management of bidirectional interlinking converter (BIC) and sub-grids in a hybrid AC/DC microgrid can lead to heavy or light load state some distributed energy resources (DERs), large deviations AC bus voltage/frequency DC voltage. This study proposes strategy based on the concept coordination factors for microgrids achieve accurate active sharing among all DERs (instead same within one sub-grid), reactive DERs, voltage restorations. Power sub-grid is achieved by following leader...

Conventionally, additional control levels are often introduced in a dc microgrid (MG) to ensure equal power sharing among distributed energy resources (DERs). To achieve this, it is necessary for the supervisory controller collect multiple operation signals of all DERs. Thus, burden communication increases with increased usage Additionally, high requirements on links decrease flexibility and reliability MGs. In this paper, an improved secondary strategy maximum loading factor (MLF) accurate...

Voltage fluctuation suppression and reactive power proportional sharing in islanded microgrids (MGs) are often difficult to maintain simultaneously. Hence, a dynamical reconfigurable master–slave control architecture is proposed herein. When load fluctuates, the leader will be dynamically selected through specific features (such as output power, voltage, capacity); subsequently, sends his information all other distributed generators (DGs) unified signal MG. Meanwhile, DGs adjust their local...

Power factor correction (PFC) can be achieved by a single-ended primary inductor converter (SEPIC) operating in boundary conduction mode (BCM) with conventional constant on-time (COT) control, but it is challenging to achieve low total harmonic distortion (THD) and high-power (PF), particularly at high input voltage. A variable (VOT) control strategy for BCM SEPIC PFC without voltage feedforward multiplier circuits proposed realize unity PF this paper. By using slope sawtooth generator whose...

Grid-forming converters (GFMs) are faced with the threat of inrush current and sever transient instability issues during grid faults, which calls for fault ride through (FRT) capability. Several FRT control strategies proposed single GFM connected to system in existing literatures while interaction mechanism among paralleled GFMs still remain unrevealed corresponding rarely discussed. To fill this gap, coordinated based on mode-switching is article. The would turn into mode periods return...

A variable on‐time (VOT) control strategy for boundary conduction mode (BCM) single‐ended primary inductor converter (SEPIC) power factor correction (PFC) with high (PF) and low total harmonic distortion (THD) is proposed. By utilising output voltage input to modulate the turn‐on time of switch BCM SEPIC PFC converter, unity PF lower THD can be achieved. The operating principles VOT controlled are analysed. experimental results based on 100 W prototype demonstrate that proposed better than...

In this paper, power system restoration was performed by changing the status of switchers on feeders. Based Multi-Agent technology, a Service Restoration System for distribution systems designed, which consists two substations JADE development platform. A Feeder-Agent set each feeder and developed to act as manager decision process. At same time, Bus-Agent bus corresponded customer loads. Through interaction negotiation between Bus-Agents Feeder-Agents, proposed can complete task service in...

A virtual synchronous generator (VSG) can provide inertial support through renewables and energy storage. It generally operates in parallel with a diesel (DSG) an islanded microgrid. However, unforeseen interactive power oscillations occur the paralleled system when loads fluctuate. These may also burn out VSG owing to its low overcurrent capacity. The mechanism suppression strategy of oscillation VSG-DSG are investigated. reveals that is caused essentially by physical difference parameter...

Virtual synchronous generator (VSG) attracts great attention for mimicking generators but suffers from transient instability. Predicting the stability is important protecting VSG. Unlike generators, quick and precise prediction needed VSG due to lack of physical inertia. In this paper, a long-short term memory (LSTM) neural network proposed predict hundreds milliseconds in future VSG's synchronousness margin, only takes dozens milliseconds. Furthermore, input output data LSTM designed based...

Conventional power management methods of networked microgrids (NMGs) are limited to the failure pinned communication terminals and heavy burdens. This paper proposes a multilevel dynamic master-slave control strategy via two-level leaders realize resilience enhanced NMGs. The first level leader with considerations distributed energy resources (DERs) feature is selected guide output DERs achieve within individual microgrid (MG). Subsequently, secondary considering each MG among bidirectional...

Solid oxide fuel cells (SOFCs) are promising distributed generation technologies for their controllability and efficiency. Traditional SOFCs controlled as a current source to deliver predefined power the grid. Since microgrid can operate in both grid-connected mode islanded mode, grid-forming control ability is required achieve voltage/ frequency regulation. However, when subjected load transients, nonlinear output characteristics of would probably lead collapse dc-link voltage unintentional...

ABSTRACT With the expansion of hybrid AC/DC microgrids (MGs), AC and DC subgrids should be able to maintain interconnection through interlinking converter (IC) under short‐circuit faults avoid system instability caused by power mutation. Conventional IC control methods have given insights into current restraining between two but neglect transient voltage/frequency support requirement, especially islanded operation mode. This paper proposes a grid‐forming with fault‐ride‐through (FRT)...

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The ever-expanding inverter-based microgrids (MGs) requires the grid-forming distributed renewable energy resources (DERs) to enhance system safety. However, different types of DERs are prone have transient conflicts with each other under short circuit faults, leading unexpected outage or even collapse. fast response and poor overcurrent capability make coordination a challenge. This paper proposes dynamically master-slave architecture for control in islanded MGs asymmetric faults. A...