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The load sharing in the DC microgrids is affected by the practical factors such as the cable resistances and changes in the system topology. This paper presents a new control algorithm for the application in the DC microgrids to achieve accurate load distribution between droop controlled converters. An identical steady state voltage feedback is used for all droop controlled converters to ensure accurate current sharing. The information about the common voltage is obtained by means of the proposed communication-less control strategy. The proposed strategy does not require prior information about the grid topology and parameters. Therefore, it is applicable to both single- and multi-bus microgrids. The conducted stability analysis demonstrates that the proposed approach and the conventional droop control deomstrate similiar dynamic performance. Furthermore, the proposed algorithm has a potential to enhance the operation of the Interlinking Converters in the hybrid AC/DC microgrids. A comprehensive nonlinear simulation study is conducted in the Matlab/Simulink environment. The simulation results verify the effectiveness of the proposed communication-less control scheme to enable proper load distribution between droop controlled converters as well as enhance the load sharing between AC and DC microgrids. Finally, the proposed control approach is verified using an OPAL-RT setup. [ABSTRACT FROM AUTHOR]

This paper presents a new control strategy for voltage source converter based Multi-Terminal High Voltage Direct Current (MTDC) systems. The proposed control approach ensures accurate power sharing between the droop-controlled converter stations. By communicating the power-sharing index between neighboring converters, the proposed approach achieves exact droop control operation independent of the DC system topology and line parameters. The pilot voltage droop based controller, which is an alternative communication-based approach for achieving precise power sharing, was used as a base case for comparison. Modal analysis is carried out to reveal the sensitivity of the system's eigenvalues to the changes in control parameters (e.g., power droop gain, proportional integral gains of the proposed controller) and the latencies in the communication. It is demonstrated that the proposed strategy remains in the stable operation even when excessive latencies are encountered in the communication. Nonlinear simulations are conducted in the MATLAB/Simulink environment in four- and five-terminal MTDC grids, validating the capability of the proposed controller to achieve the desirable performance under various operational conditions. [ABSTRACT FROM AUTHOR]

This paper presents an improved pilot voltage droop based control for the multiterminal high-voltage dc (MTDC) systems. The proposed control strategy maintains adequate power sharing and efficient voltage regulation among the converter stations. The incorporation of the average voltage sharing loop enables achieving superior dynamic performance while avoiding dc system average voltage deviation from nominal value. Furthermore, the frequency consensus algorithm is used for modifying the power reference of converters to achieve the desired frequency deviation sharing between the ac areas connected through the droop controlled voltage source converters. Finally, the incorporation of the frequency locked loop enables achieving fast grid synchronization and superior dynamic performance for the control of the converter stations. The simulations carried out in the MATLAB/Simulink environment revealed the effectiveness of the controller to provide enhanced dc voltage regulation and frequency deviation sharing during disturbances in the MTDC system. [ABSTRACT FROM AUTHOR]