نشریه تحقیقات نوین در سیستم های قدرت هوشمند
سال یازدهم شماره 4 (پیاپی 32، زمستان 1401)

In this paper, a non-isolated current-fed high step-up switching converter, is presented. In proposed converter are used of coupled-inductor and bootstrap capacitor. Input current proposed converter is continuous and compared to its high step-up counterpart has less ripple input current. With low coupled-inductor RMS current in the proposed, used of copper losses and smaller ferrite core. Also, due to common ground, common mode current is decreased. In this paper, the operational principle and characteristics of proposed converter are presented, and in order to verify the proposed converter, a 20-400V, 200W prototype converter is implemented and experimental results are provided.

Today, electric vehicles have been significantly considered due to the lack of air pollution. However, due to the large volume of vehicles in the city, connecting them to the distribution network without a control program may cause congestion in the network lines and substations. Therefore, a bi-level hierarchical method for connecting electric vehicles to the distribution network to coordinate services and performance constraints of the three main elements, namely fleet operator, distribution system operator, and capacity market operator in the presence of vehicle owners and taking into account driving requirements, charging and compaction costs of power lines and transformers are recommended. In this method, first car owners and fleet operators present their charging program to the distribution system operator according to the predicted market prices. In the next step, if this charging program leads to congestion in the lines or substations and power transformers, it is returned to the fleet operators and the shadow price is determined by the capacity market operator based on the congestion status. Then the new charging program is dispatch according to the new market prices. The proposed method is implemented in a sample distribution network and the simulation results show the efficiency of the proposed method.

This paper aims to reduce dc-link voltage fluctuations in variable speed wind energy conversion system based on permanent magnet synchronous generator (PMSG). A flywheel energy storage system (FESS) which is connected to a squirrel cage induction machine is used for dc-link of PMSG. FESS has been applied to reduce the fluctuations of the injected power into the network and to regulate the power flow, which has been carried out by sending/receiving power from FESS when there is an excess/deficiency of the network power. Type-II fuzzy logic controller is proposed to improve the PMSG performance and dc-link voltage control, that its performance has been compared with PI controller and type-I fuzzy logic controller. The grid connected converter is used to separately control the active and reactive power for achivement of unity power factor. The dynamic model of the proposed system has been simulated using MATLAB-Simulink software and the obtained results prove the effective performance of the proposed controller.

In this article, a comprehensive management plan for the operation of a multiple microgrid will be presented based on economic and environmental considerations with the formation of a coalition between microgrids with the aim of increasing the profit of microgrid operation. The proposed model is formulated as a multilevel optimization problem with a game theory approach. At the local level, the environmental and economic dual-objective optimization problem is presented for each microgrid based on distributed production and renewable energy resources. Since the problem of planning for electrical and thermal loads is applied, therefore, energy carriers such as electrical energy and fuel required by power plants are included in the optimization plan, and due to the penetration of scattered productions based on renewable energies, there is uncertainty in power. output in the microgrid, in the proposed structure, two practical tools are proposed for the optimal use of this equipment and increasing the profit of the microgrid operator, the first tool is the optimal use of energy storage resources and the second tool is responsive loads and the management plan of these loads in order to achieve The objectives of the microgrid operator will be. In this research, particle consensus algorithm as well as game theory-based modeling are used for optimization, simulation is done using Games software, and its results are implemented by implementing a collaboration space and forming a coalition between microgrids and distribution network. It has significantly reduced the final costs of the collection.

Due to the ever-increasing development of the electricity industry and the growth of consumption demand, the use of clean energy sources is increasing. In this regard, the use of wind energy as a clean and free source for the production of electrical energy is expanding day by day, and according to predictions, 20% of the world's energy will be obtained through wind by 2030. But in addition to all the advantages of wind energy, using them in the form of wind turbines in power grids in order to provide the required power can be considered a negative factor from the point of view of stability in power systems. The purpose of this article is to use the predictive control method based on logger functions to check the small signal stability of a hybrid network, including synchronous generators, wind farms and parallel STATCOM compensator. In this method, by using logger functions, the computational time in model-based predictive control has been reduced, so that the accuracy of tracking control signals can be increased and the stability of the system can be improved. The proposed method for controlling the active and reactive powers in the rotor side converter related to DFIG and the type of compensator used has been done in such a way that the performance of the power system can be increased by applying appropriate switching in the corresponding inverter. The simulation results using MATLAB software have been evaluated in the time domain, and its superiority has been clearly shown in order to improve the damping of power system fluctuations.

The reconfiguration of electric distribution networks is one of the important periodical actions in the operation phase of power networks. By using proper reconfiguration, different aspects of power quality can be improved with the lowest cost. In this article, the reconfiguration is proposed using the combination of fuzzy logic, Symbiotic Organisms Search algorithm and using the multi-objective function to reduce losses, load imbalance and improve the voltage profile. In addition, Spanning Tree Theory has been used to check the radial condition of the distribution system and connecting all the loads after reconfiguration. Considering that the objective functions do not have the same measuring units, a fuzzy system has also been used for homogenizing the objectives. The designed program has been tested on a real test network with 11 feeders and 95 buses. The final result shows the successful performance of the proposed method in providing a new topology for the distribution network with lower losses, more balanced load and better voltage profile for the intended test system.