Journal ArticleDOI
Distribution Voltage Control for DC Microgrids Using Fuzzy Control and Gain-Scheduling Technique
TLDR
In this paper, a low-voltage bipolar-type dc microgrid with two energy storage units and a dc/dc converter was proposed to achieve both power sharing and energy management.Abstract:
Installation of many distributed generations (DGs) could be detrimental to the power quality of utility grids. Microgrids facilitate effortless installation of DGs in conventional power systems. In recent years, dc microgrids have gained popularity because dc output sources such as photovoltaic systems, fuel cells, and batteries can be interconnected without ac/dc conversion, which contributes to total system efficiency. Moreover, high-quality power can be supplied continuously when voltage sags or blackouts occur in utility grids. We had already proposed a “low-voltage bipolar-type dc microgrid” and described its configuration, operation, and control scheme, through experiments. In the experiments, we used one energy storage unit with a dc/dc converter to maintain the dc-bus voltage under intentional islanding operation. However, dc microgrids should have two or more energy storage units for system redundancy. Therefore, we modified the system by adding another energy storage unit to our experimental system. Several kinds of droop controls have been proposed for parallel operations, some of which were applied for ac or dc microgrids. If a gain-scheduling control scheme is adopted to share the storage unit outputs, the storage energy would become unbalanced. This paper therefore presents a new voltage control that combines fuzzy control with gain-scheduling techniques to accomplish both power sharing and energy management. The experimental results show that the dc distribution voltages were within 340 V ± 5%, and the ratios of the stored energy were approximately equal, which implies that dc voltage regulation and stored energy balancing control can be realized simultaneously.read more
Citations
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Proceedings ArticleDOI
A Superimposed Frequency Method with an Adaptive Droop Characteristic for DC Microgrids
TL;DR: An adaptive droop characteristic is proposed to decrease the transferred reactive power and mitigate system overall voltage quality, and its performance is verified through simulation.
Proceedings ArticleDOI
Decentralized control for parallel bidirectional power converters of a grid-connected DC microgrid
TL;DR: The proposed control method consists of two parts, that is, the inner loop and the outer loop, and improves the performance of the system from the following three aspects: a d-q-0 three axis control strategy, a feedback linearization control strategy and the decentralized DC droop control.
Journal ArticleDOI
An Optimal Droop Control Method of DC Micro-grid with Local Loads
Renxi Gong,Zihao Liu +1 more
Journal ArticleDOI
Regulation Performance of Multiple DC Electric Springs Controlled by Distributed Cooperative System
TL;DR: In this paper, a set of DC electric springs with such a topology and with their non-critical load and critical load connected to a common DC bus is considered, and the control of the DCESs is built up around a distributed cooperative system having two control levels, namely primary and secondary, each of them endowed with algorithms committed to specific tasks.
Journal ArticleDOI
Backstepping predictive control of hybrid microgrids interconnected by neutral point clamped converters
TL;DR: Simulation and experimental results show that the NPC converter can regulate the DC voltage in the DC microgrid interconnection point, by adjusting the AC power conversion to compensate variations on the loads or on the distributed renewable energy sources in theDC microgrid.
References
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Hierarchical control of droop-controlled DC and AC microgrids — a general approach towards standardization
TL;DR: The hierarchical control derived from ISA-95 and electrical dispatching standards to endow smartness and flexibility to MGs is presented and results are provided to show the feasibility of the proposed approach.
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TL;DR: In this paper, a review of electrical energy storage technologies for stationary applications is presented, with particular attention paid to pumped hydroelectric storage, compressed air energy storage, battery, flow battery, fuel cell, solar fuel, superconducting magnetic energy storage and thermal energy storage.
Journal ArticleDOI
Adaptive Decentralized Droop Controller to Preserve Power Sharing Stability of Paralleled Inverters in Distributed Generation Microgrids
TL;DR: In this paper, an adaptive decentralized droop controller of paralleled inverter-based distributed generation (DG) units is presented to preserve the power sharing stability, which is based on the static droop characteristics combined with an adaptive transient droop function.
Journal ArticleDOI
Low-Voltage Bipolar-Type DC Microgrid for Super High Quality Distribution
TL;DR: In this paper, a low-voltage bipolar-type dc microgrid is proposed to supply super high quality power with three-wire dc distribution line. But, the proposed system is not suitable for large-scale systems.
Journal ArticleDOI
Fuzzy-Logic-Control Approach of a Modified Hill-Climbing Method for Maximum Power Point in Microgrid Standalone Photovoltaic System
TL;DR: In this article, a fuzzy-logic controller for maximum power point tracking of photovoltaic (PV) systems is proposed, which improves the hill-climbing search method by fuzzifying the rules of such techniques and eliminates their drawbacks.