In this article, the analysis and implementation of a hybrid algorithm for maximum Point of Power tracking in photovoltaic applications is presented. The proposed algorithm merges the Voltage Sweep technique and the Perturb & Observe (P& O) algorithm to control a T-source inverter (TSI). The quadrature-axis component, on the other hand, is set to zero to improve the system’s power factor. After calculating the reference components, they are compared to actual values, and two PI controllers handle them. Then, the Simple Boost Control technique is employed to modulate the TSI. Various operational scenarios, such as irradiance and temperature variations, were simulated (using MATLAB) and investigated to validate the efficacy of the proposed algorithm. A quantitative comparison between the three methods is included.

Microgrid is a new paradigm for current and future energy distribution systems that enable renewable energy integration.The microgrid generally consists of multiple distributed generators interfacing with the grid through power inverters.When the islanded microgrids are concerned, it is essential to maintain the system stability and achieve load power sharing among the multiple parallel-connected distributed generation units.However, poor active and reactive power-sharing is expected due to the influence of impedance mismatch of the distributed generation feeders.The key objective of this work is to estimate the virtual impedance value to nullify the power-sharing errors without the need for communication links.A fuzzy logic controller is proposed to estimate the value for virtual impedance based on the instantaneous real and reactive power demands.The virtual impedance dynamically changes depending on the load demand to compensate for the feeder impedance mismatch, hence called adaptive virtual impedance.The proposed power-sharing control strategies are validated using Matlab/Simulink simulation under four operational scenarios.The proposed fuzzy controller provides precise reactive power sharing and helps to eliminate the need for communication links.In addition, it provides superior dynamic performance.

The utilization of renewable energy resources using PV, wind turbines, and fuel cells, has grown significantly over the last decades in the power grids. This makes power electronic inverters an indispensable part of renewable energy systems as a necessary interface between these resources and the power grids. However, conventional two-level inverters (TLIs) cannot satisfy applications in high voltage ranges. Therefore, multilevel inverters (MLIs) are used for this purpose. MLIs have many advantages over conventional TLIs, particularly lower total harmonics distortion, lower electromagnetic interference, suitability for medium voltage-high power applications, minimizing dvldt across switches, higher efficiency, and larger DC link voltages. To align with high power demands, MLIs can create the desired number of levels. Recent MLIs topologies are produced with increased levels using fewer components resulting in cost minimization and increasing system reliability. Also, modulation techniques play a substantial role in improving the behavior of MLIs. This paper briefly reviews the different topologies of conventional TLIs and MLIs. A comparison between conventional TLI and MLIs is introduced. The basic concepts of the different topologies are discussed in detail. The merits, demerits, and applications of each topology are presented. The recent topologies of MLI are also highlighted. Control and modulation techniques are introduced.

Recently, controlling a wind energy conversion system (WECS) under fluctuating wind speed and enhancing the quality of power delivered to the grid has been a demanding challenge for many researchers. This paper provides a comprehensive review of synchronous generator-based WECSs. This paper will investigate the growth of wind energy in Egypt and throughout the world, as well as the technological and financial significance of wind energy. The block diagram of a typical grid-connected WECS, power control techniques, characteristic power curve-based maximum power point tracking (MPPT), and MPPT techniques are also presented in this study. Moreover, this study compares different power converter topologies for grid-connected and independent WECSs that use a permanent magnet synchronous generator (PMSG).

This paper presents an improved topology for a DC–DC converter suitable for PV applications. The proposed converter has the ability to be energized from multiple DC sources. Hence, it can be energized from two, three or a higher number of sources according to the number of modules adopted in its design. The proposed converter can supply a single load with DC power at a voltage lower or higher than the summation of all excitation DC voltages with a non-reversed voltage polarity at its output. Moreover, it provides a more reliable operation compared to other DC–DC converters due to its ability for operation with partial failures in its exciting sources. In this paper, the theoretical discussion of the proposed converter is presented considering its construction and its principle of operation. The performance of the proposed converter is theoretically evaluated using simulation based on power simulation (PSIM) software at different conditions. The performance of the converter is theoretically evaluated using PSIM considering photovoltaic (PV) sources as input sources for the proposed converter to show its validity for renewable energy applications. For more evaluation, experimental work is carried out by building a prototype and testing it at different operating conditions.

In this paper, a proposed electric drive system for a three-phase induction motor is presented. The proposed drive system is suggested for a golf car as one type of electric vehicle. The suggested system consists of three similar single-phase buck–boost converters. Hence, each single-phase buck–boost converter is used as a buck–boost inverter and is used to energize only one phase of the induction motor. The suggested system has the advantage of high reliability, as it can deal with different fault conditions such as battery and motor winding faults. The suggested electric drive system depends on a buck–boost converter which gives variable voltages as well as variable frequencies. Thus, variable speeds of the electric vehicles can be easily achieved. A variable DC voltage (positive or negative) can be achieved at the output of the adopted buck–boost converter, which is considered another advantage of the proposed drive system. This DC voltage can be used to achieve braking of the induction motor used to drive the electric vehicle. Therefore, this advantage can be used instead of ordinary mechanical braking to increase vehicle reliability. To demonstrate our proposed idea, a simulation study is presented. The simulation is carried out using Power Simulation Program (PSIM) software. The simulation study takes into consideration the performance of the adopted buck–boost converter under different conditions to present its advantages. Furthermore, a performance study of the suggested induction motor drive system is carried out under different conditions ranging from healthy to faulty conditions to test system reliability. For more illustration, an experimental prototype of the adopted buck–boost converter is built, and its performance is studied. From all the obtained results, the efficacy of the proposed system is demonstrated.

In this paper, a new design of a non-isolated high-voltage gain DC/DC converter that operates at a reasonable duty cycle, by merging the dual boost converter with the switched inductor structure, is presented as a solution for the high-conversion ratio requirement. The proposed converter operates in discontinuous-current mode (DCM) with zero current switching for all switches and diodes. Wide duty cycle range operation, high output voltage gain, low switching stress, small switching losses, and high efficiency are achieved efficiently. Operating the converter in DCM can support a wide range of the duty cycle operation, maintain lower voltage stress of all devices, ensure the same current sharing among inductors, make it easy to control, provide more stability, and require a smaller inductor which reduces size and weight of the proposed converter. Moreover, the converter operates with a continuous input current. These features make the converter a good choice for many applications such as photovoltaic, x-ray, fuel cells, etc. To prove the converter’s effectiveness, theoretical analysis, project specifications, and operation principles are presented and studied. Experimental results in an open and closed-loop, and a comparison with other recent converters are also introduced to confirm the validity of the proposed converter.

Abstract The transformerless inverter for grid-connected photovoltaic (PV) system has been an increasing interest from researchers because of the benefits of smaller size, lower cost and higher efficiency compared with the ones which have transformer. However, the leakage current which resulting in transformerless inverter because of the absence of galvanic isolation must be eliminated. In this study, a novel single-phase transformerless multilevel inverter for grid-tied PV systems is proposed. The proposed inverter can reduce the leakage current. A suitable sinusoidal pulse width modulation (PWM) is modified to utilize with the proposed inverter to produce five-level output voltage. The structure of the new circuit and its principle of operation with the modified modulation strategy are illustrated in this paper. A simulation of the proposed inverter included in grid-tied PV system with a convenient control system have been built in MATLAB/Simulink software to verify the theoretical explanations. Finally, a prototype is tested to verify the theoretical analysis and main contributions of the study.

A variety of uses are possible for the direct torque control (DTC) system that is supplied by a photovoltaic array system. The design of a photovoltaic (PV) power conversion system based on aT-Source inverter is the subject of this study. T-Source Inverter, a single stage power converter, controls the shoot through duty ratio of pulse width modulation by coupling an inductor and a capacitor in the impedance network to give boost capabilities. Mathematical modeling and analysis are offered in order to forecast the performance of the T-Source inverter. The suggested DTC with T -source inverter method has been shown to have various benefits, including small steady state error, quick reaction, and little overshoot with disturbance.

Multiphase machine models can be accurately designed and represented by means of MATLAB Simulink. This is because the dq-axis flux linkages and the torque response of the multiphase machines can be accurately expressed and described by means of lookup tables-based finite element method (FEM) simulations. However, the power electronic converters are easily implemented using MATLAB Simscape. Hence, the two MATLAB blocks should be connected together to provide the whole drive system. However, there will be a problem to easily connect the two MATLAB blocks directly. Consequently, this paper introduces a detailed description of the proposed interconnector that can be used to interface the two MATLAB blocks. A five-phase induction motor Simulink model connected to a five-phase voltage source inverter Simscape model will be presented to analyze and describe the implementation of the proposed interconnector. Finally, the simulation result of the five-phase squirrel cage induction motor, the five-phase voltage source inverter and the proposed interconnector are displayed.

This article analyses the performance of synchronous reluctance motors (SynRMs) when an existing three-phase stator is rewound (REW) to a higher number of phases. The introduced rewinding technique offers an optimized distribution for air-gap flux, higher winding factor, and higher value for the fundamental component of the magnetomotive force with lower harmonics. The number of turns of the proposed multiphase winding is calculated, keeping fixed copper volume. Finite element simulations verified that the torque density of the REW five- and seven-phase SynRMs is enhanced by 6.56% and 3.37%, respectively, over the existing machine under rated conditions. The torque ripple is also reduced by 17.13% and 15.87%, respectively. Furthermore, the efficiency is enhanced with the REW machines by 0.3% at rated condition. Moreover, the torque gain is greatly increased to 23.48% at higher speed (9000 rpm) and the efficiency is also increased by 3%. The main advantage of the REW machine is clearly observed in case of an open-circuit fault. With one-phase opened, the REW machine can work at 78% of the healthy rated torque, while the three-phase machine works at only 43% with a very huge torque ripple about 228%. Experimental measurements are obtained to validate the theoretical work.

In this study, a fuel cell and wind turbine hybrid energy system is described. Due to the intermittent nature of the power generated by wind turbines, this system is necessary. This kind of system is anticipated to be a more effective alternative that will produce no emissions. The controllers for the system's design are discussed in detail here. Using MATLAB/SIMULINK, several different operational scenarios have been simulated to evaluate the effectiveness of the controller that has been designed. The results show that the proposed controller can quickly and accurately compensate the connected loads and manage the available energy to keep the load's power as demanded.

This article compares the performance of an existing three-phase synchronous reluctance machine (SynRM) with an identical machine that is upgraded to a five-phase machine. Two different methods are possible to convert the existing three-phase machine to a five-phase one with minimum cost. In the first method, a five-phase SynRM (SynRM 1) is obtained by replacing the existing stator by another one that has an integer number of slots per pole, i.e., a multiple of five. In the second method, a five-phase SynRM (SynRM 2) is obtained by rewinding the existing stator with a special type of winding. This is because the slot number of the existing stators is not a multiple of five. The novelty of the article is that two five-phase SynRMs are compared with the original three phase reference machine in terms of torque and torque ripple, in healthy and fault conditions. At rated condition and optimal current angle, SynRM 1 performs better than SynRM 2 in terms of rated torque: SynRM 1 and 2 have 11.8% and 6.6% higher torque than the three-phase machine. But, SynRM 1 has 25% more torque ripple than the three-phase reference machine, while SynRM 2 has 17% lower torque ripple. At faulty case, SynRM 1 and 2 work at 74% and 79% of the healthy rated torque of the three-phase SynRM, while the three-phase SynRM works at only 43% with a very huge torque ripple. Finally, experimental measurements are obtained to validate the theoretical work.

This paper proposes an optimal current angle to maximize the torque under the fault condition for a five-phase synchronous reluctance machine connected to a matrix converter. The effect of fault and saturation on the dq-axis inductances is considered when selecting the operating point of maximum torque per Ampère. The healthy phases current is reconstructed to ensure a null value of zero sequence current. Space vector modulation is applied to control the matrix converter under the fault condition. Finally, the performance of the drive system is analysed.

The interest in motor drive systems with a number of phases greater than three has increased, mainly in high-power industrial fields due to their advantages compared with three-phase drive systems. In this paper, comprehensive mathematical modeling of a five-phase matrix converter (MC) is introduced. Besides that, the direct and indirect space vector modulation (SVM) control methods are compared and analyzed. Furthermore, a mathematical model for the MC with the transformation between the indirect and direct topology is constructed. The indirect technique is used to control the five-phase MC with minimum switching losses. In this technique, SVM deals with a five-phase MC as a virtual two-stage converter with a virtual DC link (i.e., rectifier and inverter stages). The voltage gain is limited to a value of 0.79. Moreover, to analyze the effectiveness of the control technique and the advantages of the MC, a static R-L load is employed. However, the load can also be an industrial load, such as hospital pumping or vehicular applications. The presented analysis proves that the MC gives a wide range of output frequencies, and it has the ability to control the input displacement factor and the output voltage magnitude. In addition, the absence of the massive DC link capacitors is an essential feature for the MC, resulting in increased reliability and a reduced size converter. Eventually, an experimental validation is conducted on a static load to validate the presented model and the control method. It is observed that good matching between the simulation and the experimental results is achieved.

Due to the significant advantages of cost savings, low temperature rises and high efficiency, synchronous reluctance machines (SynRMs) have attracted growing interest from academia to industrial applications.Numerous articles have been published to obtain a SynRM with improved performance (i.e., a high torque density and efficiency and a lower torque ripple) using different focusing points at healthy and faulty conditions such as rotor design, magnetic steel grade, stator winding, and fault tolerance control (FTC) strategy.Hence, this article reviews the scientific researches about SynRMs aiming to improve their performance.These scientific researches can be categorized into four sections: 1) optimal rotor design; 2) magnetic steel grade; 3) winding configurations; and 4) FTC strategies.

The main objective of this paper is to study the influence of severe utility voltage dips on the wind-energy-based system. The system comprises a doubly-fed induction generator (DFIG), which allows for both stator and rotor control during unavoidable events such as voltage dips. Two different techniques have been applied to keep the wind system connected to the grid during faults. The first technique implements new crowbar protection by controlling the Rotor-Side Converter (RSC) switches so that either all the upper or lower switches are on. Doing so avoids the need for hardware components such as external resistors and switches. The second technique is to modify the applied control system of the DFIG to alleviate the influence of dips on the system quickly and accurately. The main applied modification is adding a low-pass filter to ensure the steadiness of the reference current of the RSC. Both applied techniques are validated via MATLAB/Simulink simulations. A thorough comparison is presented to illuminate the merits and demerits of each technique.

This paper analyses the performance of a high reliability multiphase electric drive system. The drive system consists of a five-phase synchronous reluctance machine (SynRM) connected to a three to five-phase matrix converter (MC). In this system, there is no vulnerable electrolytic DC-link capacitors, which considered a point of failure in conventional electric drive systems. The indirect space vector modulation (SVM) is used to control the five-phase MC. Indirect SVM deals with the five-phase MC as a virtual two-stage converter consisting of a virtual DC link, a virtual rectifier stage and a virtual inverter stage. In addition, a modified closed loop field-oriented control based on the indirect SVM is proposed to control the five-phase SynRM. The performance of the drive system is analyzed at different operating conditions.

High-voltage gain DC-DC boost converter is very important because it is required in many industrial applications, and therefore becomes the focus of all researches nowadays.Conventional topologies is used to obtain high gain due to its advantages such as simple structure, simple control, and low cost but it must be operated at extreme duty cycle in order to obtain high voltage gain which leads to high semiconductors voltage stress, high switching loss, and diode reverse recovery problems that degrades the system performance, and cause a significant efficiency reduction.Using of Cascaded boost converter and switched inductor converter solve some of the problems appeared with conventional boost converter as they have higher voltage gain without working with high duty cycle like conventional one, but they have some problems such as higher losses, and lower efficiency that also degrades the system performance.This study presents a new non-isolated high voltage gain DC \ DC boost converter operating with a reasonable duty cycle by integrating dual boost converter with switched inductor structures.The presented converter operates with soft-switching ZVS mode for all switches, high voltage gain, and high efficiency.In order to prove the converter effectiveness, the theoretical analysis, operation principle, and simulation results are presented.

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.