An Effective Nonlinear Control Approach to Enhance the Voltage Stability of DC Microgrid Feeding with Constant Power Load

Abstract

Distributed generation (DG) is a crucial component of the emerging microgrid concept. It enables the integration of sustainable power in a distribution network. In DG unit activity, converters assume an indispensable part in interfacing energy sources with the grid utility. Interfacing can effectively be refined by working converters with viable control strategies. These controllers have an important role in microgrids to improve system performance, stability, resilience, and reliability. Stability issues are key hurdles in hybrid DC microgrids, where power electronic converters are used extensively to link the renewable energy source to the DC bus. Conventional linear controllers may not be able to resolve the issue of designing a robust controller for load fluctuations. A DC microgrid with renewable energy sources can achieve reduced current ripple, higher efficiency, faster dynamics, high voltage gain, and less operational stress by interfacing with an interleaved boost converter (IBC). The stability of an IBC linked to a DC microgrid supplying a constant power load (CPL) can be imperceptibly guaranteed by a conventional controller. A tightly regulated CPL with nonlinear and negative incremental impedance characteristics will lead to stability issues. Uncertainties such as load and line variations will further affect the stability of the system. This research seeks to assess the stability of constant power load integrated with a DC microgrid and to emphasize critical factors that affect voltage stability. This research reviews different control techniques that can use for DC microgrid. In addition, the specific characteristics of different control strategies are summarized to distinguish from distribution network control. Moreover, various control approaches including centralized, decentralized and distributed controls are compared according to their relative advantages and newlinedisadvantages. However, since the DC microgrid with CPL exhibits nonlinear characteristics, a linear controller cannot guarantee the...