Virtual inertia control of PV systems for dynamic performance and damping enhancement of DC microgrids with constant power loads

Abstract

DC bus voltage in islanded DC microgrids (MGs) is prone to power fluctuations of sources and loads. This is due to the lack of generational inertia, which is caused by high penetration of converter-based renewable energy sources (RESs). With the growing penetration of RESs, especially photovoltaic arrays (PVAs), they are required to provide grid support services such as inertial response in a similar way to conventional synchronous generators. Here, a virtual inertia control (VIC) is proposed for PVAs to enhance the inertia of a hybrid PVA-battery DC MG. The proposed VIC employs active power control of PVAs to provide virtual inertial response (VIR) without using any high-power energy storage system such as supercapacitors. An adaptive virtual inertia gain is introduced to achieve dynamic power sharing between the PVAs that provide VIR. Impedancebase stability analysis is utilised to study the impact of the virtual inertia gain on the system stability and to show the impact of the proposed VIC on improving the stability margin of the DC MG in the presence of destabilising constant power loads (CPLs). Finally, simulation results are presented to verify the effectiveness of the proposed method in dynamic performance and damping enhancement of the DC MG and reducing the high-current stress on the battery.

An overview of power quality enhancement techniques applied to distributed generation in electrical distribution networks

“…Although there are some researches on control, management, development, power quality improvement, utilization of DC microgrids and some home appliances compatible with DC electricity has been developed but it is not as inclusive as AC grids [157][158][159][160][161]. Power electronic converters are an inevitable part of these systems but there is a problem, and it's the overall cost of these systems that creates doubt in cost-effectiveness of power electronic based RESs.…”

Challenges and Research Opportunities of Frequency Control in Low Inertia Systems

“…Another approach to frequency control in low inertia systems is the capacity of renewable power plants providing inertial response namely synthetic inertia (SI) for power systems, which is achieved by design a control method to regulate the power output of renewable generator during frequency excursions. Different control strategies have been proposed to apply for wind power plants (WPPs) [35,36] and solar PV plants [37,38]. In general, the basic principle of this approach is managing to accelerate or decelerate the rotor speed of WPPs to absorb or provide a temporary active power to counteract power imbalances.…”

Research on Virtual Inductive Control Strategy for Direct Current Microgrid with Constant Power Loads

“…However, because the "plug-and-play" characteristics of distributed resources, new control strategies need to be designed for the access of new micro resources, which obviously lacks flexibility. In addition, other methods are also committed to using active control methods to improve system stability [19,20]. Among various approaches investigated in the literature, there is a deficiency that the influence of transmission line is not included in these study.…”