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With the enormous stress of energy lack and air pollution, renewable energy sources such as photovoltaic sources become an effective solution to solve these problems. The penetration of inertia-less photovoltaic sources into power system has adverse effects on the overall system inertia which threatens system stability. As a solution for this problem, virtual inertia technique can be used as a system controller in order to enhance the system performance and maintain its stability. In this paper, an adaptive virtual synchronous generator (VSG) controller based on the oscillation motion of the synchronous machine is introduced. Then, a proposed VSG with adaptive neuro-fuzzy inference system (ANFIS) is presented as an inverter controller. The system response is investigated and compared with other control methods under different operating scenarios. To verify the effectiveness of the proposed adaptive VSG, an experimental setup is presented with real-time implementation for the system using dSPACE DS1104 interfacing with MATLAB software, and the system response is investigated under different operating scenarios. Upon the presented results, there is an enhancement in the system response when the proposed adaptive VSG with ANFIS controller is used, and this emphasizes the superiority of using such controller in PV systems over other techniques.

This paper presents cascaded boost AC-AC converter with control strategy. The proposed system can attain high-gain voltage by using low-voltage rating switch devices. The control technique leads to nearly unity power factor and the required high voltage at stop working unit (SWU). The output voltage can be controlled up to double the input voltage multiplied by the number of units. The proposed converter has many advantages such as, low number of semiconductor switches, nearly sinusoidal output voltage, and negligible distortion in the supply current and load voltage waveforms. The proposed cascaded converter is suitable to be extended because all the AC - AC converter units have similar construction, control strategy, and operating conditions. Accordingly, maintenance is simple and the defective unit can be easily detected and compensated. The prototype converter with several numbers of units is constructed and tested to verify the performance. The proposed circuit and control technique is validated by the simulation results with MATLAB software.

Distribution networks planning is a very complex task as it involves the consideration of various important issues. A model for optimal planning of a distribution network is presented in detail, using Distributed Generation (DG). This paper presented a detailed analysis of the West Delta Network (WDN) as a part of the Egyptian distribution network with a 30% increase in system loading. An Oscillatory Particle Swarm Optimization (OPSO) technique was used to find the optimal locations and sizes of one DG or multiple DGs for achieving the objectives of minimizing total active power losses and system voltage regulation as a single-and-multi-objective optimization problem in a distribution network. Several penetration scenarios have done to evaluate concentrated (at one location) and distributed DGs (at different locations). The results are presented in a comparative form and thoroughly discussed. The obtained results will help in system operation with DG integration and identifying the critical penetration levels for the studied system.

This paper presents a proposed five-level inverter based on conventional five-level Neutral Point Clamped (NPC) topology which is a type of Multilevel Inverters (MLIs). MLI is a great solution for high power application in addition to medium power, low power and renewable energy applications. The proposed topology reduces the number of input DC sources as compared with the conventional five level NPC topology. Also, this circuit reduces the conduction losses by reducing number of switches that turned on in each mode. The circuit operation analysis in each mode is illustrated. A proper modulation strategy based on Pulse Width Modulation PWM is applied on the proposed circuit. The simulation of the proposed circuit is carried out in MATLAB/SIMULINK environment. The results show a comparison between conventional five-level NPC and modified circuits which illustrate a good performance for the proposed one which make it suitable for many applications such as photovoltaic systems.

This paper proposes a single-stage three-phase boost inverter for Photovoltaic (PV) applications. The proposed circuit topology is directly step-up the input low level DC voltage to a high-level output AC voltage in only one stage, using an inductor and six switches. A new control methodology is introduced to regulate the AC output voltage and current and is suitable for grid-connected and stand-alone applications. The proposed circuit uses only six switches of a simple type of switches that achieve the desired objectives easily without additional antiparallel diodes. The circuit topology is extensively analysed and the overall performance including total harmonic distortion (THD) is obtained by computer simulation and presented under different conditions. A DSP-based laboratory model is built to assess the proposed single-stage three-phase boost inverter when fed from a PV source. The experimental results confirm the simulation, illustrating the successful operation of the proposed circuit topology to produce three-phase AC output from the low DC voltage of the PV source.

This paper proposes a transformerless/non-isolated, high-gain DC-DC converter required to increase low voltages in renewable energy applications. The converter topology uses only a single-switch wi...

This paper introduces a split-capacitor shunt Active Power Filter (SC-APF) based on Synchronous Reference Frame (SRF) theory. This topology is used in compensating the currents of 3-Ph unbalanced n...

This paper introduces a Four-Switch Three-Phase Shunt Active Power Filter (FSTP-APF) based on One Cycle Control (OCC) technique for compensating the currents of three phase non-linear loads. The po...

A proposed topology for a high-efficiency single-stage single-Phase boost inverter with a simple circuit configuration and a low component count is proposed in this paper. The proposed inve...

This article presents an accurate computational technique for estimating the photovoltaic (PV) cell parameters from experimental measurements of the current-voltage ( I - V ) characteristics. The technique is based on using various evolutionary algorithms (EAs) and the double-diode eight-parameter cell model to precisely estimate unknown parameters. The proposed technique is implemented to extract the PV cell parameters of different manufacturer's modules by minimising the summation of absolute square errors between theoretical and measured I - V output characteristics obtained under different irradiation levels. The effectiveness and robustness of the proposed technique are demonstrated via a comparative assessment of the measured output I - V characteristics and those obtained by computer simulation, using Matlab SIMSCAPE library components. The good agreement obtained between theoretical and experimental results endorses the proposed approach to determine precisely the PV parameters required for power system studies. The proposed technique is useful power system studies with penetration of photovoltaic sources.

The integration of distributed generators (DGs) into distribution networks in optimal allocation is one of the main issues facing power system engineers to ensure improved stability and economic operation. This article presents a detailed analysis of the impacts of the optimal allocation and the number of DGs on both system steady‐state and transient performances of distribution networks. An oscillatory particle swarm optimization (OPSO) algorithm was used to find the optimal allocations of DGs via minimizing various objective functions that deal with Total Transmission Losses, Voltage Regulation, and Power Performance Index. The OPSO is used to optimize these functions as a single and as a multiobjective optimization problem. The effectiveness of the method is demonstrated with the IEEE‐14 bus as an example of distribution networks with a 50% increase in system loading. Two penetration scenarios have been considered, the optimal sizes and locations of DGs are obtained, and the results are presented. In addition, the impact of the penetration level of Photovoltaic and Wind Energy sources on transient performance is obtained using detailed nonlinear models of both synchronous machines and DGs sources. The system response is then obtained when the system is subjected to a three‐phase short circuit fault for six cycles and the results are presented in a comparative form for different penetration levels. The techniques and results presented in the article form a useful base for power system engineers in planning and operating distribution systems with high penetration levels of RDG sources.

This study proposes a new three-phase dual-rotor middle-stator brushless flux switching generator for 400Hz diesel-driven aircraft ground power units. For the proposed machine, both field and armature windings are hosted in the stator in such a way that not only fulfils brushless structure, but also realises the flux switching function. Moreover, both windings have non-overlapping concentrated windings to shorten the end-windings and reduce the copper losses. In the meantime, the rotor has only slots without any active parts. First, the machine detailed design is provided, and its performance is analysed using finite element method. Also, a selection topology of both stator and rotor pole arcs is carried out, targeting maximum generated electromotive force, minimum harmonic content, and minimum cogging torque. Then, a prototype is implemented and experimented to confirm the feasibility of the proposed machine.

The integration of distributed generators (DGs) into distribution networks is one of the main issues facing distribution networks. This paper presented a detailed analysis of the impacts of the renewable DGs allocation on system steady state and transient performance of distributed networks. An oscillatory particle swarm optimization (OPSO) algorithm was used to find the optimal locations and sizes of DGs for achieving the objectives of minimizing total transmission losses, system voltage regulation or real power performance as a single- and multi-objective optimization problem in distribution networks. The effectiveness of the method is demonstrated with the IEEE14 bus as a distribution network with 50% increase in system loading considering several penetration scenarios to evaluate concentrated and distributed DGs. Also, the impact of DGs penetration on system transient performance was obtained using detailed non-linear models of both synchronous machines and DGs sources (Photovoltaic and wind) when the system was subjected to a symmetrical three-phase short circuit fault for 6 cycles. The obtained results will help in planning the system with high penetration levels of renewable DG sources and identifying the critical penetration levels for the studied system.

Photovoltaic have the characteristics of nonlinear I-V and P-V characteristics. With the variation of illumination level and temperature, different maximum power points could be obtained. A method to track the maximum power point (MPP) called voltage based method is proposed in this paper. This proposed method of MPP decrease the power loss delivered to the load or grid. The proposed method decrease the sensors used that decrease system cost and increase its reliability. The proposed method is applied on a single-phase single-stage DC-AC boost inverter. The boost inverter is transformer less which decreases size, cost and weight and increases the overall efficiency. Principle of operation, theoretical analysis are discussed. Simulation and experimental results for both the proposed method of MPP and inverter control used are presented also.

This paper deals with a double stage standalone solar photovoltaic (PV) water pumping system. Using speed vector controlled Induction Motor Drive (IMD), motor speed estimated through stator flux. The system consists of a PV array, high-gain DC-DC converter, Three-Phase Voltage Source Inverter (VSI) and a motor-pump assembly. To extract maximum power from a solar PV system, a modified Maximum Power Point Tracking (MPPT) technique is utilized. Field Oriented Control of an IMD (FOC-IMD) is applied to attain the soft starting of the motor. The system setup is prepared and simulated in the environment of MATLAB/Simulink. The modeling, control technique of the system is implemented. A prototype of the experimental model is advanced in the lab. The results achieved illustrate the system suitability for PV water pumping application.

With the enormous stress of energy lack and air pollution, renewable energy sources such as photovoltaic sources become an effective solution to these problems. The penetration of photovoltaic sources into power system has adverse effects on overall moment of inertia and damping, this threatens system stability. To assist the stability, the concept of virtual synchronous generator (VSG) has introduced as an inverter control method to add virtual inertia to the system. This paper demonstrates the effects of adding virtual inertia on the system performance when fed from a photovoltaic source. The effects of changing the system and VSG parameters on the overall performance is also studied to show the appropriate change in each parameter that enhance the performance. The theoretical results that obtained using the MATLAB/SIMULINK are verified experimentally, using a DSP-based laboratory model that fed from a PV source.

Inappropriate choice of locations and sizes of Renewable Energy Sources (RESs) in electric power systems can have an adverse impact on voltages profile, transmission losses and system reliability. This paper proposes a technique for finding the optimal locations and sizes of (RESs) in electric power system using oscillatory particle swarm optimization (OPSO). The technique is applied to the IEEE 9-bus as a test system with a 30% increase in system loading considering various penetration scenarios that assess distributed and concentrated RESs. The technique finds the optimal allocation via minimizing transmission losses, bus voltage deviation or line loading as a single-or-multi-objective optimization problem. Impact of RESs penetration on system transient performance is also obtained using detailed non-linear models of both conventional synchronous machines and RESs. The results are presented illustrating the system performance when exposed to a three-phase short circuit fault for 6 cycles. The results are of prime importance to power system engineers forming a useful guide in system planning and also in system operation.

This paper introduces a design of a three-phase flux switching machine (FSM), which is mainly designed for a 400 HZ aircraft auxiliary power unit. In this design, there are two winding sets embedded in the stator slots. One, is referred to as three phase armature windings, supply the power to the aircraft electrical system. The other winding, namely excitation winding, is fed from a dc supply. Also, a slotted rotor will be designed without any winding or permanent magnets. Moving the field winding to the stator not only ensures brushless construction, but also reduces generator weight through the direct coupling between the generator and the gas turbine. The machine is initially simulated using 2-D finite element analysis (FEA) and its performance is analyzed. Additionally, a prototype is implemented, and its performance is practically measured in order to prove the validity of the proposed machine for aircraft auxiliary power units.

This paper presents theoretical and experimental analysis of the performance of a photovoltaic system supplying DC loads and controlled by either a cuk or a sepic converter. The nonlinear mathematical model of the system is obtained, considering all operation modes of both converters. A fairly detailed nonlinear simulation was built to assess the performance when system is supplying constant and dynamic loads. Simulation and experimental results are presented illustrating both the steady state and the starting characteristics of the system. The relation between solar irradiation level and the duty ratio for both steady–state and run-up for the cuk and sepic converters have also been given to ensure maximum energy utilization. The results are presented in a comparative form which clearly illustrates that the cuk converter operates over a wider range of irradiation levels. The results also show that with a proper design of photovoltaic generator and careful selection of the dc-dc converter, the performance of a particular application can be optimized by controlling the converter duty ratio.

This paper presents a parameter estimation technique to determine the photovoltaic (PV) cell parameters from experimental measurements, using the direct search optimization method. A double diode model is considered to represent a photovoltaic (PV) cell, and a Matlab simulation is built to demonstrate the effects of varying various parameters on the output performance. The direct search optimization technique is used to estimate the cell parameters by reshaping the simulated output characteristics to match similar experimental measurements. The procedures that illustrate the implementation of the proposed technique to estimate the PV cell parameters are detailed. The technique is implemented to estimate the parameters of SUNSET PV Module Model PX-170 from experimental measurements. The convergence characteristics of the most sensitive cell parameters are given. The validity of the proposed technique is verified by comparing simulated results obtained using the estimated parameters and their corresponding ...