scholarly journals Multi-level bus voltage compensation of droop control with enhanced load-sharing capability for DC microgrid

2019 ◽  
Vol 2019 (16) ◽  
pp. 3056-3061 ◽  
Author(s):  
Sucheng Liu ◽  
Zhongpeng Li ◽  
Wenjie Liu ◽  
Xiaodong Liu
2021 ◽  
Author(s):  
Mohammadreza Nabatirad ◽  
Reza Razzaghi ◽  
Behrooz Bahrani

The conventional droop control is a widely-used technique in load sharing among Distributed Generator (DG) units in islanded DC Microgrids (MGs). This method provides Plug-and-Play (PnP) capability for DG units; however, poor load sharing accuracy and unregulated voltage are two shortcomings of that. This article proposes a novel control system in islanded DC MGs to provide simultaneous regulated voltage and accurate load sharing. The method utilizes a modified droop control technique in a decentralized manner. The proposed control system injects a superimposed AC voltage to the network that carries a frequency proportional to the master DG unit output current. The injected voltage adjusts an added a term to the conventional droop control named as the voltage compensation term in order to cancel voltage changes. This term adjusts terminal voltage of DG units proportional to the frequency of the superimposed AC voltage. The performance of the proposed control system is validated via a set of simulation studies using PLECS, and the experimental results confirm the viability and feasibility of the proposed control system.


Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2995 ◽  
Author(s):  
Liang Zhang ◽  
Kang Chen ◽  
Shengbin Chi ◽  
Ling Lyu ◽  
Guowei Cai

In the direct current (DC) microgrid composed of multiple distributed generations, due to the different distances between various converters and the DC bus in the system, the difference of the line resistance will reduce the current sharing accuracy of the system. The droop control was widely used in the operation control of the DC microgrid. It was necessary to select a large droop coefficient to improve the current sharing accuracy, but a too large droop coefficient will lead to a serious bus voltage drop and affect the power quality. In view of the contradiction between the voltage regulation and load current sharing in the traditional droop control, a hierarchical control algorithm based on the improved droop control of the fuzzy logic was proposed in this paper. By improving the droop curve, the problems of voltage regulation and current sharing were solved simultaneously. The effectiveness of the algorithm was verified by simulation.


This paper is representing power management in a hybrid microgrid. The hybrid microgrid consists of PV, wind, battery, and grid. The power management strategy is mentioned in islanding and grid-connected mode. In a grid-connected system, the grid converter has to monitor and manage the power to flow between microgrid and grid. The voltage shifting based droop control technique is used in DG for proper load sharing when two sources are connected in parallel. DG units in hybrid microgrid have two switching modes including droop control and maximum power tracking (MPPT). The operation of a hybrid microgrid is operated in different thee mode. The bus voltage is the main carrier to switching the mode of a hybrid microgrid. The power management algorithm for hybrid microgrid described here. This renewable-based hybrid microgrid model can be used for different aspects like small residential and commercial buildings. The feasibility and effectiveness of this strategy for hybrid microgrid running in various modes verified by simulation result.


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