A new method to control a micro-grid consisting of various distributed generation (DG) units which are connected to the distribution grid is presented in this paper. In this regard, an energy-management algorithm based on robust control is realized to coordinate the performances of the battery in the micro-grid for grid-connected networks and islanded performances. The designed controller for DG inverters employs a novel algorithm of predictive control which provides faster computation time for high consumer power systems by improving the transient control and steady-state problems, separately. In addition, a micro-grid consisting of a proton-exchange membrane fuel cell (PEMFC), a photovoltaic (PV) array, and a lithium-ion storage battery (SB) is considered. In order to reduce the overall computation time of the system, the designed controller for DG inverters employs a newly developed MPC algorithm which decomposes the control problem into transient sub-problems and steady state. The entire presented system is simulated using MATLAB and then simulation results illustrate the effective performance of the proposed system. Micro-grids with renewable DGs such as solar cells and lithium-ion batteries that are connected to the network via converters are used as the reactive power compensation of nonlinear loads. A robust control method is used for controlling the inverter switches for batteries connected to the power network. An approach based on a robust control study is used in the formation of H_infinity, considering the transient and steady-state response when the system voltage and frequency have priority. Assessments use this method to control voltage and frequency in micro-grid scenarios پرونده مقاله

In this paper, to develop the dynamic performance of an islanding mode micro-grid, which contains a wind turbine unit and a gas distributed generation (DG), simultaneous usage of H infinity and robust control are presented. By using the doubly-fed induction generator (DFIG) and the variable speed wind turbine, the system inertia is decreased and then the dynamic stability is also decreased. The virtual inertia implementation in DFIG causes the power system stability improvement. However, the major challenge that should be considered is the change in the system parameters or uncertainties, when the virtual inertia is employed. In this paper, the implementation of virtual inertia in the DFIG control system is described in detail and the impact of uncertainties and changes in the control system parameters over the performance of the frequency control system are investigated. In order to improve the dynamic stability and the steady state performance of the frequency control system, benefiting from the impact of virtual inertia, the mixed robust H infinity control approach is proposed. The simulation results using MATLAB software show that the proposed hybrid controller guarantees system stability in conditions of uncertainties and with the variation of the control system parameters. پرونده مقاله

The Load Frequency Control (LFC) has been a major subject in electric power system and is be-coming more significant system in recent decades. This paper targets to investigate the problem of LFC in interconnected power systems in order to obtain robust state. In this paper, a design method for a robust controller, based on PID, has been presented to overcome the robustness against uncertainties. To achieve optimal PID, Particle Swarm Optimization (PSO) has been em-ployed to obtain coefficients of the SMC. Variations of uncertain parameters are considered be-tween -40% and +40% of nominal values. The simulation results show that the system response with the proposed PID is better than the conventional PID controller. It is also shown that the transient response of the tie line power can be improved. پرونده مقاله