Amin Hajizadeh

Voltage Control and Active Power Management of Hybrid Fuel-Cell/Energy-Storage Power Conversion System Under Unbalanced Voltage Sag Conditions

This paper concentrates on the control of hybrid fuel-cell (FC)/energy-storage distributed generation (DG) systems under voltage sag in distribution systems. The proposed control strategy makes hybrid DG system work properly when a voltage disturbance occurs in distribution system, and it stays connected to the main grid. To distribute the power between dc power sources and stabilize the dc-link power, a Lyapunov-based neuro-fuzzy control strategy has been developed. This controller determines the supercapacitor power that should be generated according to the amount of available energy in dc-link. Also, current control strategies for the FC converter (boost) and supercapacitor converter (buck-boost converter) are designed by proportional-integral and sliding-mode control consequently. Moreover, a complementary control strategy for voltage source converter based on positive and negative symmetrical components is presented to investigate the voltage sag ride-through and voltage control capability. The hybrid system is studied under unbalance voltage sag condition. Simulation results are given to show the overall system performance including active power control and voltage sag ride-through capability of the hybrid DG system.

Power Flow Control of Grid-Connected Fuel Cell Distributed Generation Systems

This paper presents the operation of Fuel Cell Distributed Generation (FCDG) systems in distribution systems. Hence, modeling, controller design, and simulation study of a Solid Oxide Fuel Cell (SOFC) distributed generation (DG) system are investigated. The physical model of the fuel cell stack and dynamic models of power conditioning units are described. Then, suitable control architecture based on fuzzy logic and the neural network for the overall system is presented in order to activate power control and power quality improvement. A MATLAB/Simulink simulation model is developed for the SOFC DG system by combining the individual component models and the controllers designed for the power conditioning units. Simulation results are given to show the overall system performance including active power control and voltage regulation capability of the distribution system.

Intelligent robust control of hybrid distributed generation system under voltage sag

In this paper, design of control strategy for hybrid fuel cell/energy storage distributed power generation system during voltage sag has been presented. The proposed control strategy allows hybrid distributed generation system works properly when a voltage disturbance occurs in distribution system and hybrid system stays connected to the main grid. To distribute the power between power sources, a Lyapanov based neuro-fuzzy control strategy has been developed during voltage disturbances. Then, a fuzzy sliding-mode control strategy is presented for designing the controllers DC/DC and DC/AC converters. Simulation results are given to show the overall system performance including active power control and voltage sag ride-through capability of the hybrid distributed generation system.

Intelligent control of hybrid photo voltaic/fuel cell/energy storage power generation system

This paper proposes a control strategy for hybrid power generation systems including fuel cell and photovoltaic as the main energy sources and battery energy storage as the auxiliary power source. The overall configuration of the hybrid power generation system is given, dynamic models for the fuel cell, photovoltaic and battery bank and its power electronic interfacing are briefly described, and controller design methodologies for the power conditioning units and power sources to control the power flow from the hybrid power plant to the utility grid are presented. Then, a control strategy is presented for designing the controllers of power sources, DC/DC and DC/AC converters, to manage the power flow both on the DC and AC sides. Simulation results are given to show the overall system performance including load-following and power management of the system.

Control of hybrid fuel cell/battery distributed power generation system with voltage sag ride-through capability

In this paper controller design for voltage sag ride-through in hybrid fuel cell/battery energy storage distributed power generation system has been presented. As the amount of fuel cell power generation and other distributed generation (DG) with power electronic in the grid grows, it becomes unacceptable to disconnect generating units every time a disturbance occurs, as was common practice in the past. Keeping the VSC on line during unbalanced voltage sags becomes thus a very critical issue. Hence, modeling, controller design, and simulation study of a hybrid distributed generation system are investigated. Based on the classification of unbalanced faults that can occur in the grid, resulting in voltage sags at the bus where the hybrid power system is connected, the maximum current that the converter valves must be bale to withstand is calculated. Simulation results are given to show the overall system performance including active power control and voltage sag ride-through capability of the hybrid distributed generation system.

Control of a hybrid wind turbine/battery energy storage power generation system considering statistical wind characteristics

This paper presents controller design and simulation studies of a hybrid wind turbine/battery energy storage power generation interface to control active and reactive power in distribution systems. First, the modeling of grid-connected hybrid power system was illustrated. A known Weibull distribution presented the wind speed. Further analysis has been considered based on the law of large number and the wind power generated from a closed-form. Power electronic converters used to connect hybrid power system to the AC system. Fuzzy sliding mode controller for the voltage source converter has been presented to control reactive and active powers in the utility grid. In order to verify the proper operation of the proposed controller, a known load profile has been considered. Finally, simulation results have been illustrated to show power flow control capability of the developed control strategy in distribution systems.

Lyapunov Based-Distributed Fuzzy-Sliding Mode Control for Building Integrated-DC Microgrid With Plug-In Electric Vehicle

This paper presents a distributed control strategy based on fuzzy-sliding mode control (FSMC) for power control of an infrastructure integrated with a dc-microgrid, which includes photovoltaic, fuel cell, and energy storage systems with plug-in electric vehicles (PEVs). In order to implement the proposed control strategy, first, a general nonlinear modeling of a dc-microgrid based on related dc–dc converters to each dc power sources is introduced. Second, a power management strategy based on fuzzy control for regulating the power flow between the hybrid dc sources, PEVs is proposed. Third, to retain the balance between the requested power and the output power, adaptive FSMC strategy, for controlling the battery energy storage and fuel cell, is suggested. Finally, experimental results are presented to validate the potential of the proposed power flow control strategy.

Control of hybrid PV/Fuel Cell/Battery power systems

In this paper, a hybrid power system based on dc-coupled hybrid PV/Fuel Cell/Battery power system that supports the local grid is presented. Part of the local active and reactive power demand is supplied by the hybrid power system. Consequently, the grid operates at or near unity power factor at the point of common coupling (PCC). First, modeling of system components is presented. Then, an effective control staregy is developed to manage the power flow both on the DC and AC sides. Finally, simulation results are presented to demonstrate the effectiveness of proposed control strategy.

Impacts of distribution network characteristics on penetration level of wind distributed generation and voltage stability

Analysis of the effects of wind distributed generation (DG) on voltage stability of distribution networks is presented in this paper. A test system which is consisting of a wind farm connected to a distribution network is studied. Simulation studies are carried out using MATLAB-Simulink software. The results show the effects of different factors such as short circuit capacity and network reactance to resistance ratio of distribution system on its voltage stability and the critical values for the parameters can be determined.

Intelligent Control of Fuel Cell Distributed Generation Systems

This paper presents modeling, controller design, and simulation study of a Solid Oxide Fuel Cell (SOFC) distributed generation (DG) system. The overall configuration of the SOFC DG system is given, dynamic models for the SOFC power plant and its power electronic interfacing are briefly described, and controller design methodologies for the power conditioning units to control the power flow from the fuel cell power plant to the utility grid are presented. A MATLAB/Simulink simulation model is developed for the SOFC DG system by combining the individual component models and the controllers designed for the power conditioning units. Simulation results are given to show the overall system performance including active power control and voltage regulation capability of the distribution system.