Abstract
•Integrated 3-D droop control scheme is proposed for bidirectional DC-DC converters.•Novel approach is suggested for decoupling charging and discharging modes of EVs.•Multi-purpose interlinking converter with coordinated 3-D droop is introduced.•Power management is enhanced through accurate power sharing among converters.•Optimal reactive power compensation is achieved using an adjustable DSTATCOM.
Hybrid microgrids (HMGs) are impacted by a wide range of operational issues, which can lead to technical challenges for these systems. Power management and power sharing accuracy remain two major concerns due to lack of appropriate control strategies for bidirectional DC-DC converters (BDCs), which transfer power between distributed generations (DGs), such as electric vehicles (EVs), and HMGs. Similarly, interlinking converters (ICs), which are essential for power exchange between the AC and DC sides, can further intensify this challenge. Such deficiencies can pose threats to efficient operation of HMGs. To address these issues, this paper proposes a 3-D droop-based control scheme for BDCs, designed to coordinate the performance of both EVs and BDCs on the DC side. This approach ensures accurate power sharing between BDCs despite unequal line resistances and enhances the overall power management of the HMG by involving EVs in meeting the load demand. Additionally, a novel approach for decoupling the charging and discharging modes of the EVs is introduced to eliminate circulating power among parallel BDCs. Consequently, BDC losses will be minimized, and their operational capacity remains unburdened, as unnecessary performance is avoided. Furthermore, a multi-purpose IC, formed by integrating a conventional single-stage IC with an adjustable distribution static synchronous compensator (DSTATCOM), equipped with a coordinated 3-D droop control is suggested. This not only facilitates the AC side voltage regulation (VR) through optimal reactive power compensation, but also ensures accurate reactive power sharing among parallel ICs. To accomplish this, the capacitance of the DC-link of the DSTATCOM is optimized by precisely tuning the proposed 3-D droop gains of the IC. The effectiveness of this control strategy is demonstrated and compared with other methods in the literature using an HMG testbed.