Constant Power Loads in DC Microgrids: A Review of Modern Nonlinear Control Approaches and Stabilisation Techniques

In recent dc microgrids (dcMGs), the naval motors and hotel loads are constantly powered by point of load converters these are precisely regulated, which perform as constant power loads (CPL). One of the most important CPL's characteristics is the negative incremental impedance, it decreases effective damping of the system, which leads to instability of the whole system, and this is a significant challenge in the system operation and control. This behavior tends to destabilize the dc bus voltage of dcMGs under uncertain environments. To stabilize as well as control the CPL of dc micro grids, the robust control of the dc bus voltage is essential. This article presents a cutting-edge comprehensive review on sophisticated nonlinear control techniques of Sliding Mode Control, Predictive Control, Back-Stepping Control, and Passivity-Based Control. This review paper addresses the modeling aspects, CPL characteristics and their impacts. It also addresses the most recent stabilization methods as well as emerging developments towards adaptive nonlinear control.