An adaptive PI based distributed control method to maintain accurate power sharing and voltage regulation in DC Microgrids

In DC-Microgrids accurate load power sharing among the sources available and DC bus voltage restoration are the major issues. This paper proposes a secondary control layer to accomplish accurate and proportional load sharing, voltage regulation. In contrast to existing methods, single variable per converter is communicated in the low-bandwidth communication line, and with an adaptive PI controller as the secondary level; both objectives are accomplished at a time. The secondary control compares the average power with the corresponding converter power, the error is processed to the adaptive PI controller whose gains are the function of error. Compared to conventional PI the adaptive PI controller performs well under dynamic operating conditions as its gains are not fixed. The proposed secondary control approach is compared with the traditional droop control method, under dynamic variations such as variations of solar irradiation and temperature for PV, different loads. The proposed algorithm's effectiveness is validated using MATLAB/Simulink.