In this paper,the synchronization stability challenges of same-rated frequency interconnected microgrids(IMGs)with fully inverter-based generation units are studied.In this type of weak power grid with low X/R ratios ...In this paper,the synchronization stability challenges of same-rated frequency interconnected microgrids(IMGs)with fully inverter-based generation units are studied.In this type of weak power grid with low X/R ratios and low line impedances,no strong source with a high-inertia rating exists with which other generation units can be synchronized.Two IMGs controlled using a pinning consensus-based control architecture are considered.The inrush power flow at the beginning of the interconnection process is modeled and analyzed.This power flow is affected by the voltage/phase/frequency difference of the IMG points of common coupling.A small-signal model of the IMGs is obtained that includes a synchronization control unit,and small-signal stability is analyzed based on sensitivity analysis of the most important control and operational parameters.In addition,the transient stability of a nonlinear model of the IMGs under study as implemented in Sim Power Systems/MATLAB is investigated.Stable synchronization is more challenging than the synchronization of multi-area strong power grids and grid-connected MGs.However,synchronization can still be performed by selecting more limited ranges for the control gains and threshold values of the synchronization algorithm.Nevertheless,different disturbances such as high load conditions can cause synchronization instability.展开更多
In this paper,inspired by the concept of virtual inertia in alternating current(AC)systems,a virtual impedance controller is proposed for the dynamic improvement of direct current microgrids(DCMGs).A simple and inexpe...In this paper,inspired by the concept of virtual inertia in alternating current(AC)systems,a virtual impedance controller is proposed for the dynamic improvement of direct current microgrids(DCMGs).A simple and inexpensive method for injecting inertia into the system is used to adjust the output power of each distributed generation unit without using additional equipment.The proposed controller consists of two components:a virtual capacitor and a virtual inductor.These virtual components can change the rate of change of the DC bus voltage and also improve the transient response.A small-signal analysis is carried out to verify the impact of the proposed control strategy.Numerical simulation studies validate the effectiveness of the proposed solution for increasing the inertia of DCMGs.展开更多
This paper gives a summary on recently available technologies for decentralized and distributed control of microgrids.They can be classified into two general categories:1)power line communication based architectures a...This paper gives a summary on recently available technologies for decentralized and distributed control of microgrids.They can be classified into two general categories:1)power line communication based architectures and 2)multi-agent based architectures.The essential control methods and information sharing algorithms applied in these architectures are reviewed and examined in a hierarchical manner,in order to point out benefits they will bring to future microgrid applications.The paper is concluded with a summary on existing methods and a discussion on future development trends.展开更多
文摘In this paper,the synchronization stability challenges of same-rated frequency interconnected microgrids(IMGs)with fully inverter-based generation units are studied.In this type of weak power grid with low X/R ratios and low line impedances,no strong source with a high-inertia rating exists with which other generation units can be synchronized.Two IMGs controlled using a pinning consensus-based control architecture are considered.The inrush power flow at the beginning of the interconnection process is modeled and analyzed.This power flow is affected by the voltage/phase/frequency difference of the IMG points of common coupling.A small-signal model of the IMGs is obtained that includes a synchronization control unit,and small-signal stability is analyzed based on sensitivity analysis of the most important control and operational parameters.In addition,the transient stability of a nonlinear model of the IMGs under study as implemented in Sim Power Systems/MATLAB is investigated.Stable synchronization is more challenging than the synchronization of multi-area strong power grids and grid-connected MGs.However,synchronization can still be performed by selecting more limited ranges for the control gains and threshold values of the synchronization algorithm.Nevertheless,different disturbances such as high load conditions can cause synchronization instability.
文摘In this paper,inspired by the concept of virtual inertia in alternating current(AC)systems,a virtual impedance controller is proposed for the dynamic improvement of direct current microgrids(DCMGs).A simple and inexpensive method for injecting inertia into the system is used to adjust the output power of each distributed generation unit without using additional equipment.The proposed controller consists of two components:a virtual capacitor and a virtual inductor.These virtual components can change the rate of change of the DC bus voltage and also improve the transient response.A small-signal analysis is carried out to verify the impact of the proposed control strategy.Numerical simulation studies validate the effectiveness of the proposed solution for increasing the inertia of DCMGs.
文摘This paper gives a summary on recently available technologies for decentralized and distributed control of microgrids.They can be classified into two general categories:1)power line communication based architectures and 2)multi-agent based architectures.The essential control methods and information sharing algorithms applied in these architectures are reviewed and examined in a hierarchical manner,in order to point out benefits they will bring to future microgrid applications.The paper is concluded with a summary on existing methods and a discussion on future development trends.
