Arabian Journal for Science and Engineering

, Volume 42, Issue 12, pp 5071–5081 | Cite as

Intelligent Distributed Control Techniques for Effective Current Sharing and Voltage Regulation in DC Distributed Systems

  • Shivam
  • Ratna Dahiya
Research Article - Electrical Engineering


The droop control method is a basic technique for parallel operation of source converters. The cable line resistance of source converters is one of the causes for circulating current, degradation of load sharing, and poor voltage regulation in DC microgrid application. The control objective of microgrid is to minimize trade-off between bus voltage regulation and effective current sharing. The distributed control technique based on droop control is superior among other control technique in terms of expandability and reliability. This paper presents a distributed control technique which not only helps an effective solution for parallel operation of source converters, but also facilitates availability of maximum power to the load. The droop resistance of distributed controller is adjusted by using a fuzzy inference system in order to reduce the bus voltage degradation. This proposed scheme offers simplicity and robust control over the existing distributed control scheme. The performance of the DC microgrid which consists of three source converters with different cable line resistances and common load is verified in the MATLAB/Simulink environment.


Droop control Fuzzy inference system Hysteresis current control DC microgrid 

List of Symbols


Duty cycle


Distributed energy units


Fuzzy inference system


Large negative


Large positive


Medium negative


Medium positive


mth source converter


Suffix of ith source converter


Output current

\(i_{\mathrm{o},i}^\mathrm{rated} \)

Rated output current of source converter

\(I_{\mathrm{ref},i}^\mathrm{pu} \)

Reference current in per unit

\(I_i^\mathrm{rated} \)

Rated input current of source converter

\(\Delta i_{12} \)

Current difference between converters 1 and 2

\(\Delta i_{12}^{\prime } \)

\(\Delta i_{12} \) for higher values of \(r_{\mathrm{d},i} \)

\(\Delta i_{12}^{{\prime }{\prime }} \)

\(\Delta i_{12} \) by the adjusted value of \(r_{\mathrm{d},i} \)

\(\Delta i\)_\(_{{i-j}}\)

Current difference between ith and jth converter


Reference current


Average reference current


Source input current in steady state

\(\Delta I\)

Hysteresis current band


Number of parallel source converters


Reference power


Rated power

\(r_{\mathrm{d,o}} \)

Constant droop resistance value

\(r_{\mathrm{d},i} \)

Droop resistance

\(r_\mathrm{d} \)

Equal droop resistance value

\(r_{\mathrm{d},i}^{\prime } \)

Higher droop resistance value

\(r_{\mathrm{d},i}^{{\prime }{\prime }} \)

Adjusted droop resistance value

\(\Delta r_{\mathrm{d},i} \)

Incremental droop resistance


Cable line resistance


Load resistance


Equal cable line resistance


Small negative


Small positive


Integral time constant


Local output voltage reference


Bus voltage reference

\(\Delta V_{\mathrm{max}}\)

Maximum DC bus voltage regulation

\(\Delta V_\mathrm{o}\)

Bus voltage regulation

\(\Delta V'_\mathrm{o}\)

\(\Delta V_{\mathrm{o}}\) by the higher value of \(r_{\mathrm{d},i} \)


Output voltage


Source voltage


DC bus voltage

\(\delta V_{\mathrm{o},i}\)

Reference offset voltage


Low-pass filter cutting frequency


Impedance of cable line




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Copyright information

© King Fahd University of Petroleum & Minerals 2017

Authors and Affiliations

  1. 1.National Institute of TechnologyKurukshetraIndia

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