The growing utilisation of non-linear loads poses significant challenges to power quality in electrical grids. Non-linear loads, such as three-phase diode rectifiers, produce substantial harmonics, necessitating effective control methods to mitigate harmonic distortions. The implementation of active power filters (APF) offers significant potential for enhancing harmonic compensation performance. Accordingly, this research introduces a non-singular fast terminal sliding mode controller (NFTSMC) integrated with proportional multi-resonant (PMR) based control for a three-phase APF. The primary objective of this approach is to achieve rapid and precise tracking of reference currents while simultaneously injecting the desired currents into the electrical grid. Furthermore, to reduce harmonics generated by high-switching-frequency inverters, incorporating an LCL filter with an active damping strategy is essential. The PMR controller generates capacitor voltage references, ensuring zero steady-state error in the grid current and facilitating the implementation of the active damping method. Simulation results demonstrate the ordinary sliding mode controller (SMC) by achieving significantly lower total harmonic distortion (THD). Additionally, it exhibits superior dynamic response and robustness presence of uncertainties.

Battery energy storage systems (BESSs) have recently been utilized in power systems for various purposes. Integrating these devices into power systems can enhance the damping capability of subsynchronous oscillations. The interaction between the control modes of the BESS and synchronous machines, as well as the control parameters of the BESS, reduces subsynchronous oscillations. To damp oscillations and improve dynamic stability, this work develops a linear model of a power system integrated with a BESS to investigate small-signal stability. The gain tuning of the BESS controller is formulated as an optimization problem and is solved using a fuzzy-based algorithm. The efficacy of the proposed method is evaluated under various operating conditions. Furthermore, the proposed method is compared with a power system stabilizer (PSS) damping controller, and the results demonstrate the superiority of the BESS damping method in mitigating subsynchronous oscillations and enhancing the dynamic stability of power systems. Lastly, eigenvalue analysis is employed to determine the permissible ranges of BESS parameters for stable power system operation.

With the increasing complexity of smart power grids and the presence of distributed energy sources, the need for accurate and fast methods for fault locating is felt more than ever. In this study, a combination of two approaches based on convolutional neural networks (CNNs) is presented: first, wave matrix image analysis to locate faults in the distribution network, and second, the use of a feature fusion framework based on a one-dimensional CNN and prior knowledge to improve the accuracy of the fault detection. The proposed hybrid model, while increasing the accuracy of diagnosis by about 98.3%, also reduced the dependence on the volume of educational data. These results show that the integration of 2D and 1D CNN methods can provide an efficient approach to fault locating in Intelligent networks.

In this paper, the performance of a super twisting sliding mode controller (STSMC) is investigated for a multifunctional single-stage inverter that connects a photovoltaic (PV) system to the three-phase utility grid supplying the non-linear load. In this work, the single-stage inverter is controlled to improve power quality by compensating the current harmonics of nonlinear load and to inject maximum power from the PV system to the grid with ST-SMC controller. In this way, the ST-SMC controller is implemented to adjust the DC bus voltage to the value determined by the maximum power point tracking (MPPT) algorithm, as well as to the single-stage inverter current control using the synchronous reference frame theory. According to the simulation results, the ST-SMC controller provides high robustness and better performance in transient and steady state conditions. The results show that the total harmonics distortion (THD) of the grid current is reduced to 1.75% and the DC bus voltage reaches its set-point at 0.08 second with a small amount, approximately 0.05%, of the overshoot. In addition, the superiority and accuracy of the proposed scheme is verified by replacing conventional SMC and PI controllers with super twisting sliding mode controllers. Evaluate the suggested scheme’s performance is done using theMATLAB/Simulink software.

The main goal of the power distribution system is to provide stable and reliable electricity to consumers. In recent years, the addition of distributed generation (DGs) resources and microgrids has led to significant advances in how to assess the reliability of the network. Therefore, it is crucial to investigate and improve the reliability of distribution networks to ensure high-quality and uninterrupted service. Remote controlled switches (RCSs) are essential in this process. They quickly isolate faulty sections from the rest of the healthy network. This study proposes a planning framework that uses a genetic algorithm to find the best locations for RCSs, DGs, and tie lines. The model seeks to improve the overall reliability of the distribution system while reducing the operating and investment costs of the network.

This paper introduces a novel control law and energy management algorithm tailored for a boost-derived three port converter (TPC) employed in a standalone PV system. This converter can be used to interconnect a PV array, a battery and a resistive load through its three ports. Thanks to the devised energy management strategy, the converter exhibits three distinct operating modes, enabling it to efficiently utilize PV-generated power and battery storage based on real-time demand. Additionally, the control scheme ensures maximum power point tracking (MPPT) at the PV side and maintains the output voltage at the desired level for the load. Furthermore, proactive monitoring of the battery’s state of charge (SOC) safeguards against overcharging by automatically transitioning the converter to operate as a simple boost converter when necessary. Simulation results validate the effectiveness and robustness of the proposed energy management and control methodology, emphasizing its potential for enhancing the performance and reliability of standalone PV systems.

This study proposes a new enhanced boost dc/dc converter with high-voltage boost ability. The proposed converter takes the advantage of a continuous source current with negligible ripple, and the start-up inrush current is limited as well. Compared with the traditional extended switched-boost dc–dc converter, this converter generates higher output voltage while the numbers of components in the Z -source network of both converters are the same. Moreover, the peak values of the currents provided by the input source and crossing the active devices are reduced. In addition, the ripples of the previously mentioned currents are noticeably decreased in this topology; thus, the losses are reduced. In this article, the operation principles in continuous-conduction mode and discontinuous-conduction mode, the voltage gain, and the parameters design of the proposed converter are analyzed. Finally, by presenting the simulation and experimental results, the performance of the proposed converter is assessed.

Droop control method is an effective technique utilized in control of active/reactive power in microgrids without any need to communication links. However, the accurate reactive power-sharing cannot be achieved by conventional droop control because of mismatched line impedance and non-inductive local loads in microgrids. To overcome the problem, an enhanced droop control is proposed in this paper. The proposed method helps to decrease cost and increase the reliability of the system without the use of any communication links. It is based on a wavelet transform technique to recognize and synchronize the distributed energy resources when the load changes in the microgrid. Fast transient response, accurate frequency regulation and proper reactive power sharing are achieved by the proposed method. The simulations are carried out in MATLAB/Simulink and the obtained results demonstrate the appropriate performance of this method.

In the present article, the boost factor of the Z-source inverter is noticeably increased by using the switched-inductor structure. The proposed inverter is based on the switched-inductor Z-source inverter which has two series diodes in its switched-inductor. In the proposed ZSI instead of these two series diodes, two capacitors are used. In comparison with the conventional structure, in the smaller duty cycle ratio the proposed structures generate higher voltage. Besides, in the second proposed structure to reduce the voltages on the capacitors of the Z-source network, a dc source is placed between the inverter bridge and the Z-source network. The dc source and the inverter have common ground in both the proposed structures. The conventional and proposed inverters are thoroughly investigated to find out their governing relations, then, the boost factor and voltage across capacitors in both proposed and conventional inverters are compared with each other by simulating them in PSCAD/EMTDC. Next, the prototypes of the proposed inverters with 25 V dc input voltage are used to evaluate the obtained results.

Grid-tied voltage source inverters (VSIs) with LCL filters are a promising solution for transmitting renewable energy to the grid, but they have a high tendency to resonance. To address this issue, various control techniques have been explored. This study proposes a sliding mode control with proportional-resonant (PR) control for LCL grid-tied inverters (GTIs). A PR controller is used to generate the reference capacitor voltage, eliminating the need for a derivative operation that is not always preferred in control methodologies. A sliding mode observer is also proposed to reduce sensor requirements and enhance system stability. The proposed method is evaluated for an inverter connected to an unbalanced network experiencing voltage fluctuations, swell, and sag. The effectiveness of the method is demonstrated through simulation using Matlab/Simulink.

This paper proposes two nonlinear exact and simple state space models of a Zsource converter (ZSC) connected to an ac grid.A generic model of a ZSC accompanied with proper controllers are proposed and a dynamic model of the whole system is derived; as a result, based on a simple one, an equivalent block diagram of the current-controlled ZSC system is proposed.The ac small signal stability method is applied and the impact of controller parameters on network's stability is discussed.Besides, overall system dynamic performance has been assessed in the event of perturbations.Time-domain simulations have been implemented in PSCAD/EMTDC to validate the accuracy of the models and effectiveness of the proposed controllers.The results of the exact model are compared with the response of the equations which are applied in MATLAB.

This paper proposes a fully distributed scheme to solve the day-ahead optimal power scheduling of networked microgrids in the presence of different renewable energy resources, such as photovoltaics and wind turbines, considering energy storage systems. The proposed method enables the optimization of the power scheduling problem through local computation of agents in the system and private communication between existing agents, without any centralized scheduling unit. In this paper, a cloud-fog-based framework is also introduced as a fast and economical infrastructure for the proposed distributed method. The suggested optimized energy framework proposes an area to regulate and update policies, detect misbehaving elements, and execute punishments centrally, while the general power scheduling problem is optimized in a distributed manner using the proposed method. The suggested cloud-fog-based method eliminates the need to invest in local databases and computing systems. The proposed scheme is examined on a small-scale microgrid and also a larger test networked microgrid, including 4 microgrids and 15 areas in a 24-h time period, to illustrate the scalability, convergence, and accuracy of the framework. The simulation results substantiate the fast and precise performance of the proposed framework for networked microgrids compared with other existing centralized and distributed methods.

The induction generator in wind turbine application is subjected to fluctuations caused by polluted grid, tower shadow, and wind speed variations. The oscillations introduced by the mentioned factors especially the low frequency ones make the fault detection in induction generator difficult. In this paper, a model-based technique using the Unscented Kalman filter is proposed for rotor electrical fault detection of a wound rotor induction generator in wind turbine applications. The proper model of induction machine, and the proper measurements and states are introduced, and the corrections need to be considered in calculations are presented. The per-unit calculation makes the algorithm setting easier than the case of using real values. Several scenarios consisting of distorted grid voltage, tower shadow effect, variable wind speed, grid-connected and islanded mode, and low speed operations are studied. The fault detection is assessed thoroughly in the aforementioned conditions by means of simulations. The experimental results prove the effectivity of the proposed technique.

This article introduces an uncertainty-aware cloud-fog-based framework for power management of smart grids using a multiagent-based system. The power management is a social welfare optimization problem. A multiagent-based algorithm is suggested to solve this problem, in which agents are defined as volunteering consumers and dispatchable generators. In the proposed method, every consumer can voluntarily put a price on its power demand at each interval of operation to benefit from the equal opportunity of contributing to the power management process provided for all generation and consumption units. In addition, the uncertainty analysis using a deep learning method is also applied in a distributive way with the local calculation of prediction intervals for sources with stochastic nature in the system, such as loads, small wind turbines (WTs), and rooftop photovoltaics (PVs). Using the predicted ranges of load demand and stochastic generation outputs, a range for power consumption/generation is also provided for each agent called “preparation range” to demonstrate the predicted boundary, where the accepted power consumption/generation of an agent might occur, considering the uncertain sources. Besides, fog computing is deployed as a critical infrastructure for fast calculation and providing local storage for reasonable pricing. Cloud services are also proposed for virtual applications as efficient databases and computation units. The performance of the proposed framework is examined on two smart grid test systems and compared with other well-known methods. The results prove the capability of the proposed method to obtain the optimal outcomes in a short time for any scale of grid.

Parabolic carrier PWM method is considered as one of the direct current control methods which has been proposed for the voltage-source converters (VSCs). This method has an excellent dynamic response. Besides, it proposes a constant switching frequency by employing a pair of parabolic PWM carriers. However, it suffers from some drawbacks and limitations. The major drawback of this method is its sensitivity to the inductance variations. In other words, in grid-connected applications the exact value of grid inductance should be exactly known to achieve a proper performance from this method. Moreover, it is essential that during each switching cycle the voltage at the point of common coupling remains constant. In grid connected applications such as active power filter these drawbacks may lead to operate at variable or non-expected frequencies. Therefore, this paper concerns the suggestions to deal with the situation. In this paper, by applying the conventional method the aforementioned problems are examined in a grid-connected active power filter. It is shown analytically that by using the proposed method, problems of sensitivity to inductance changes and also necessity to constant voltage at point of common coupling in a switching period will be solved. Finally, simulation and experimental results are presented.

This paper is aimed to propose an improved boost DC-DC converter, based on the idea of switched-capacitor and switched-boost converters. A modified version of the conventional switched-capacitor switched-boost converter is proposed, particularly suitable for high power applications. The major contributions concern the reduction of the stress in the power components as well as the voltage ripple reduction. Indeed, the current of the switches as well as the current of the diodes are reduced in the proposed converter. Nevertheless, the proposed idea slightly affects the boost factor of the converter. The performance of the proposed step-up DC-DC converter is evaluated through some simulations done in MATLAB.

To improve the performance of the power electronics interface, used to connect the photovoltaic panel to the grid or load, a modified active-switched quasi Z-source inverter (MAS-qZSI) is proposed in this paper. The proposed topology offers a higher boosting capability with fewer numbers of components and less voltage stress on switches. The viability of the proposed converter is evaluated through the simulations carried out using Matlab/Simulink software package.

In this article, a new structure of the switched-inductor/capacitor quasi Z-source inverter (SLC-qZSI) is proposed that has a high boost factor in a high modulation index to provide an improved quality output voltage. Additionally, this structure has features such as equal and low voltage stress on capacitors of SLC cells and diodes, identical current ripple for the source and all inductors, a low shoot-through (ST) current in the main switches, and a continuous input current with no startup inrush current. The performance of the proposed structure is confirmed using MATLAB/Simulink software, and the simulation results are validated by using a prototype of the proposed structure.