scholarly journals An Implementation of Parallel Buck Converters for Common Load Sharing in DC Microgrid

Information ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 91 ◽  
Author(s):  
Sikander Ali ◽  
Tang Shengxue ◽  
Zhang Jianyu ◽  
Ahmad Ali ◽  
Arshad Nawaz
Keyword(s):  
Control Level ◽  
Load Sharing ◽  
Current Control ◽  
Simulation Software ◽  
Buck Converters ◽  
Droop Control ◽  
Primary Control ◽  
Dc Microgrid ◽  
Current Sharing ◽  
Circulating Current

The increase in demand for clean, safe, and environmentally friendly renewable energy sources faces several challenges such as system design and reliable operations. DC microgrid (MG) is a promising system due to higher efficiency and natural interface to renewable sources. In the hierarchical control of DC Microgrid, the V-I droop control is deployed usually in primary control level for common load sharing between converters. However, conventional droop control causes improper current sharing, voltage variations, and circulating current regulation due to the presence of droop and line resistance between converters. The aim of this paper is to presents the primary control level design of buck converters in current mode control according to the concepts of time constant and time delay, and secondary control design for parallel operations in distributed manners by combining methods, namely, low bandwidth communication (LBC), circulating current minimization techniques, and average voltage/current control. Moreover, different time delays are used for two converters to testify the effects of communication delays on current sharing and voltage restoration. The simulation is done for 2 × 2.5 KWdc parallel buck converters in PLECS (a Simulation software used for high speed simulation for power electronics) environment which shows excellent results in minimizing circulation currents, enhancing proportional current sharing, and restoring the grid voltage.

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
Keyword(s):  
Load Sharing ◽  
Droop Control ◽  
Dc Microgrid ◽  
Voltage Compensation ◽  
Multi Level ◽  
Bus Voltage

scholarly journals The Hierarchical Control Algorithm for DC Microgrid Based on the Improved Droop Control of Fuzzy Logic

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2995 ◽  
Author(s):  
Liang Zhang ◽  
Kang Chen ◽  
Shengbin Chi ◽  
Ling Lyu ◽  
Guowei Cai
Keyword(s):  
Fuzzy Logic ◽  
Control Algorithm ◽  
Voltage Drop ◽  
Hierarchical Control ◽  
Voltage Regulation ◽  
Droop Control ◽  
Dc Microgrid ◽  
Current Sharing ◽  
The Difference ◽  
Bus Voltage

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.

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