Integrated bus voltage control method for DC microgrids based on adaptive virtual inertia control

Conventional droop control is mainly used for DC microgrids. As a result, DC bus voltage suffers from rapid changes, oscillations, large excursions during load disturbances, and fluctuations in renewable energy output. These issues can greatly affect voltage-sensitive loads. This study proposes an integrated control method for the bus voltage of the DC microgrid to solve the abovementioned problems. This system mainly includes an improved adaptive virtual inertia control (IAVIC), an oscillation suppressor, and a voltage compensator. In particular, the IAVIC adaptively adjusts the virtual inertia coefficient according to the voltage change rate during load disturbance, which enhances system inertia to slow bus voltage changes and improves system dynamic characteristics. On this basis, the oscillation suppressor significantly reduces voltage oscillation by eliminating the high-frequency oscillation component of the bus voltage. In this way, the oscillation component of the voltage can be prevented from entering the control link to cause the next oscillation of the voltage. In addition, the voltage compensator enables deviation-free regulation of the bus voltage, which solves the problem of severe bus voltage dips when the load power increases. The proposed integrated control method achieves optimization of the dynamic characteristics of the DC bus voltage, oscillation suppression, and deviation-free regulation. The validity of the proposed method is experimentally verified.