A Modified Droop Control Method for DC Microgrid with Improved Voltage Regulation and Current Sharing

DC Microgrid is becoming more popular because of its attracting characteristics such as high efficiency, high power quality, reduced cost and controllability. Conversion stages will be greatly reduced in case of DC microgrid as compared to AC microgrid. The conventional droop control algorithms are widely used for managing load current sharing; the functionality of conventional droop is greatly influenced by the circuit parameters such as line resistance. Because of which the output voltage of each converter may not be same, in such condition the load current sharing may get degraded. With the larger droop gain current sharing error can be minimized, but the voltage deviation exceeds the limit, so with the conventional droop always there exists a tradeoff among current sharing performance and voltage regulation. To address the limitations of voltage regulation and power sharing error a modified droop control algorithm is proposed in this paper, which provides equal load current sharing with enhanced voltage regulation. The proposed control algorithm is having a secondary control layer along with the droop controller, secondary layer consists of an average voltage, an average current controller are used at each converter in order to achieve accurate load sharing and improved voltage regulation. The effectiveness of the proposed algorithm is verified using MATLAB Simulink.