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The reliability of the power converter (PC) must be considered a very important aspect of the design of new topologies. Multilevel inverters have a higher number of devices, which reduces the reliability of such a converter. In this letter, a new single-source switched-capacitor-based high-gain converter has been proposed. The fault analysis of the proposed topology has been carried out, and based on the analysis, a fault-tolerant version of the proposed topology has been proposed. A detailed power quality analysis has been carried out for different fault cases. Experimental results have been used to validate the proposed topology.

Future transportation will replace the current mechanical combustible engines with chargeable electric vehicles (EVs). The DC-Dc boost converter is an essential part of such systems that not only helps to generate the required level but also helps to regulate the load voltage. In conventional boost converter topologies, their gain, switching losses, and high voltage stress across switches are the main reason for limiting the output power. Coupled inductor-based isolated converters increase the system weight and cost. Therefore, in this paper, a transformerless adjustable gain and non-isolated DC-DC boost converter with multi-port flexible power supply, reduced switch voltage stress, and considerable good range efficiency is proposed. The proposed converter is tested with the 100 W resistive load to test the desired characteristics.

This study proposes a new control strategy for the quasi Z-source two-level three-phase inverter, accurate discontinuous SVM (AD-ZSVPWM). The proposed AD-ZSVPWM control technique enhances the output power quality by reducing total harmonic distortion (THD) and conduction losses. Low THD is achieved by increasing the algorithm’s accuracy using a division of six vector states in each switching period and the distribution of six shoot-through states within the period. The conduction losses are reduced by splitting each sector into two subsectors of 30°. The proposed control scheme has the following advantages: reduced THD, low conduction loss, and increased boosting factor. MATLAB/Simulink software is used, and an experimental test is conducted to validate the proposed strategy. PLECS software is utilized to calculate the switching and conduction losses. For experimental verification, a hardware test bench comprising a dSPACE DS1104 board that controls a three-phase quasi Z-source inverter that supplies an R-L load is used. Simulation and hardware results show that the proposed scheme provides improved performance in terms of power quality and power loss reduction.

This article discusses the potential of using modular multilevel converters (MMC)s in large-scale photovoltaic (PV) systems. A novel modular circuit configuration for the integration of the PV system into the grid using MMC is proposed. The proposed circuit is modular, scalable, and has excellent performance during extreme PV shading conditions. Unlike other PV-MMC circuits, this circuit configuration eliminates the power unbalance between the arms of the converter. This feature enables the converter to deal only with the power unbalance occurring between the phases which eases the control process and ensures a wide range of power balancing of the MMC. A control strategy is adopted to provide a balanced operation of the converter under different conditions. It eliminates the power unbalance between the MMC phases by only injecting the dc circulating current component while the ac component is excluded which reduces the internal losses and increases the stability of the converter. The proposed circuit configuration and the control strategy are tested using the RT box Hardware-in-the-Loop technology. The corresponding analysis and results are provided to demonstrate the effectiveness and the excellent dynamic performance of the proposed system during various PV power generation conditions.

•With the single DC power supply and 12 switches, 13 or 9-level output voltage can be generated.•Boosting of 3 or 4 times the input dc supply voltage is possible with parallel operation of the switched-capacitor during discharge mode.•The negative level is generated without the requirement of H-Bridge.•Lower voltage rating of switches and capacitors.

A multilevel inverter (MLI) with a step-up feature has become significant for connecting a low-voltage PV system with a utility grid. An MLI has been presented in this article with a lower component count. The described structure has achieved nine distinguish voltage levels using 12 switches and a switched capacitor unit having twice voltage boost. A self-balancing of the floating capacitor voltage without any auxiliary circuits and precharging has been obtained. The new topology includes fewer switches, reduced voltage stress, and an inherent reversing polarity without the back-end H-bridge, which has been the additional feature of the proposed circuitry. The topology proposed has been controlled with the nearest level control pulsewidth control technique (NLC-PWM). A comprehensive comparative analysis with several similar topologies has been presented in this article to show the merits of the recommended topology. A number of simulation results using PLECS software have been discussed along with experimental results that have been obtained from a laboratory prototype. The validation of the proposed topology has been carried out using different steady-steady and transient operating conditions.

The modular multilevel converter (MMC) is considered a very promising candidate for medium-voltage and/or high-power grids. One of the major concerns in half-bridge MMCs, especially with large number of levels, is the fault occurs at the converter submodule (SM). Hence, an appropriate control with an SM fault tolerance of the MMC is required to enhance its reliability. This paper addresses the issue and proposes a fault tolerant control-based adaptive carrier phase disposition pulse width modulation (AC-PDPWM) technique for MMCs with superior symmetrical and asymmetrical fault-tolerant capabilities. The proposed control-based AC-PDPWM acts to regulate the flow of energy between arms, rebalance the SM capacitors, and redistribute the pulses to the SM switches. In this study, a single-phase grid connected MMC having both symmetrical and asymmetrical fault conditions is investigated. Compared with other control methods, the proposed control can tolerate the SM fault conditions without requiring redundant SMs or additional computational burden, which decreases the cost and volume of the MMC design and simplifies its control. Simulation and experimental results are included to verify the fault-tolerant capability of the proposed control.

Australia’s waste management is heavily dependent on landfill. The Australian Bureau of Statistics predicts that as Australia’s population and economy grow, there will be a significant increase in the magnitude of waste output. Concentrated solar driven pyrolysis has been identified as a promising means in creating renewable liquid fuel and improving waste management. This technology is based on the upgrading of waste into a valuable commodity. This is of interest to city councils, communities and stakeholders, as both Australia’s annual waste generation and energy demands are growing rapidly. This paper provides a case for the implementation of solar-driven pyrolysis for biofuel production in the Australian state of Victoria as well as a comparative analysis of different Renewable Energy Sources and biomass reactions to justify the combination of Concentrated Solar Power with pyrolysis. This study is the first to assess the solar-driven pyrolysis under a Victorian setting. Victoria was chosen due to the comprehensive and readily available waste data kept by its government. The review concluded that a combination of Fresnel Reflector CSP and pyrolysis are best suited for regional Victorian environment. Fresnel reflector technology was found to complement slow pyrolysis well due to its 250–500◦C operating temperature, while regional Victoria was found to be a good trade-off between feedstock distance and DNI exposure. These requirements were important because feedstock transportation was found to cost $AUD 96 per 500km, and it was observed that there could be up to 1200 kWh/m2solar exposure difference between Victorian rural and metropolitan locations. This study provides a comprehensive framework of technical requirements pertaining to a Victorian solar-driven pyrolysis system, which will then act as a guidance for future designers.

A tremendous growth in installed photovoltaic (PV) capacity and widespread use makes solar energy an important renewable energy source today. Voltage fluctuations and power quality problems are becoming more and more of a problem as the integration of PV power plants expands. In response, grid-connected PV systems' operational issues and the fluctuation of PV power generation have been addressed via the development of flexible power point tracking (FPPT) solutions. This review study provides a comprehensive analysis of FPPT strategies for PV power generation systems. It categorizes and describes various FPPT methods, studying their tracking performance under different working conditions and analyzing their underlying principles. One key advantage of FPPT strategies lies in their ability to operate PV systems below their maximum power point, thereby allowing for better control and active power reserve. Additionally, these strategies can provide essential grid support services, such as voltage control and frequency support. The work provides a baseline for scientists and researchers looking to adopt appropriate FPPT approaches. This research reveals common trends and efficient procedures for future investigations by contrasting methods based on their properties, such as their operating region selection and performance under partial shading circumstances.

Accurate state of charge (SoC) estimations are vital to guarantee the safe and efficient operation of Lithium-ion battery systems in electric vehicles. In this paper, an improved coulomb counting method with adaptive error correction (ICC-AEC) with dual closed-loop control system (DCLCS) for SoC estimation is proposed. Where, a DCLCS with first-order RC battery modeling using forgetting factor-based recursive least square (FF-RLS) algorithm is utilized to achieve high estimation accuracy by recalibrating the SoC factor and fast response time. To evaluate and validate the performance of the proposed algorithm, a dynamic load profile with a large range of temperature variation is considered. Further, SoC estimation results obtained from traditional mixed method (MM) with closed-loop control system (CLCS) and proposed ICC-AEC with DCLCS are compared. The results show that the SoC estimation error obtained from ICC-AEC with DCLCS is lesser than MM with CLCS under considered dynamic operating conditions.

The operation of small-scale wind turbines in high-speed wind conditions continues to pose a number of problems to this industry, turbine owners, and communities, over which this paper presents a comprehensive discussion of the operation and control of these energy conversion systems under such challenging conditions. A pitch control mechanism is widely used in medium- and large-scale wind turbines; however, such a complex mechanism is too expensive for small wind turbines. Due to these critical conditions and the avoidance of higher costs associated with electromechanical systems, electrical stall control strategies integrated with maximum power point tracking (MPPT) algorithms have become well known as a method for controlling wind turbine operation in various weather conditions, from low- to high-speed winds. During low- and medium-speed wind conditions, the wind turbine follows the MPPT control loop to extract the maximum amount of energy from the wind, while capturing the maximum power is not achievable in high-speed wind conditions by increasing the wind speed, and the control loop has to be switched to stall mode to handle such conditions, under which this paper reviews the existing stall-control techniques in a comprehensive manner.

Longest geographically connected Australian power system is undergoing an unprecedented transition, under the effect of increased integration of renewable energy systems. This change in generation mix has implications for the whole interconnected system designs, its operational strategies and the regulatory framework. Frequency control policies about real-time balancing of demand and supply is one of the prominent and priority operational challenge requiring urgent attention. This paper reviews the Australian electricity market structure in presence of wind energy and its governance. Various issues related to increased wind generation systems integration are discussed in detail. Currently applied mitigations along with prospective mitigation methods requiring new or improved policies are also discussed. It is concluded that developing prospective frequency regulation ancillary services market desires further encouraging policies from governing authority to keep pace with current grid transition and maintain its security.

The gradual depletion of fossil-fuel-based energy resources and the growing rate of greenhouse gas emission are two of the most significant global concerns in recent years. These concerns have resulted in an increasing demand for the utilization of renewable energy resources. From among all renewable resources, hydropower is the leading contributor to grid-connected electricity in the world. In this article, the hydropower potential in Malaysia, current and future prospects of large and small-scale hydropower development, and issues and challenges related to hydropower development are described. Small hydropower promotion techniques, government initiatives, and the advantages and barriers to small hydropower development are also included.

The design of frequency regulation services plays a vital role in automation and eventually reliable operation of power system at a satisfactory and stable level. Frequency response capability offered by wind plant is not same as the primary control capability of conventional plants, hence the integration of wind energy based generation at large scale has widespread impacts on power system stability and reliability. With the changing generation mix, modern electric power systems are facing a critical challenge in the real‐time balancing of demand and supply. This paper comprehensively reviews the various control functionalities available in wind energy systems for supporting frequency regulation at different levels of frequency control services starting from inertial control to the secondary control. An insight to new research challenges for better frequency control ancillary services in wind integrated system is also provided. Though wind-based ancillary services are still in research and development stage in most of the countries, future wind energy system participation is expected to contribute to enhanced market efficiency, improved system reliability and macro economic benefits to all stakeholders.

In Somalia, access to electricity impedes economic growth and sustainable development. Despite having abundant solar energy potential due to its location near the equator, the utilization of solar energy in Somalia is still limited due to unfamiliarity, lack of energy awareness, high initial costs, and lack of infrastructure. The Somali government has established the National Regulatory Authority and set a goal to increase energy access from 15 to 45% by 2024 through the National Development Plan (NDP) 9th (2020–2024). This study aims to analyze and verify the utilization and potential of solar energy in Somalia to understand opportunities and challenges and identify suitable areas and technologies for development. This study explores Somalia's energy profile and the potential for harnessing solar energy. The installed photovoltaic capacity was found to be 41 MW and contributed 11.9% of the total electricity generation. A case study on a solar power microgrid system in Bacadweyene, Somalia, is also presented. The research provides valuable information on the status of the utilization and potential of solar energy in Somalia and aligns with the NDP 9th. The results can serve as a scientific framework for companies and researchers to seek feasible strategies for future investment in solar energy applications in Somalia.

In recent years, increasing interest has been shown in targeting energy efficiency as a roadmap for carbon mitigation, limiting energy use, improving buildings’ energy performance, and reducing energy consumption for achieving sustainable buildings. This article presents a systematic review to provide the best practices in this area and identify the challenges, motivations, recommendations, and pathways for future work. Discussing the methodological aspects gives insights for future researchers. This research used papers published on three scientific and reliable databases—Web of Science, ScienceDirect, and IEEE Xplore-from 2014 to May 23, 2021. The selected papers reached N = 134 based on inclusion and exclusion criteria and divided into review papers, proceeding conference, and articles. The review articles (N = 16/134) give an overall view on improving energy efficiency to achieve sustainability in buildings by using green building rating systems, developing and implementing policies, technology utilization, adopting techniques, and applying strategies. The conferences (N = 33/134) and articles (N = 85/134) focus more on details of different aspects of improving energy efficiency by reducing environmental, economic, social, and other impacts. A few articles proposed multiple-criteria decision-making methods to solve energy efficiency gaps for promoting sustainability in buildings. Achieving energy efficiency toward sustainable buildings is a hot topic in the sustainable development area. The outcomes from this paper will provide a valuable reference to stakeholders, governments, and decision-makers and give suggestions from the selected past studies. This review will provide motivation and attract future research endeavors in the field.

The COVID-19 pandemic has threatened city economies and residents' public health and quality of life. Similar to most cities, Melbourne imposed extreme preventive lockdown measures to address this situation. It would be reasonable to assume that during the two phases of lockdowns, in autumn (March) and winter (June to August) 2020, air quality parameters, air temperature, Surface Urban Heat Island(SUHI), and lighting energy consumption most likely increased. As such, to test this assumption, Sentinel 5, ERA-5 LAND, Sentinel 1 and 2, NASA SRTM, MODIS Aqua and Terra, and VIIRS satellite imageries are utilized to investigate the alterations of NO₂, SO₂, CO, UV Aerosol Index(UAI), air temperature, SUHI, and lighting energy consumption factors in the City of Melbourne. Furthermore, satellite imageries of SentiThe results indicate that the change rates of NO₂ (1.17 mol/m2) and CO (1.64 mol/m2) factors were positive. Further, the nighttime SUHI values increased by approximately 0.417 °C during the winter phase of the lockdown, while during the summer phase of the lockdown, the largest negative change rate was in NO₂ (−100.40 mol/m2). By contrast, the largest positive change rate was in SO₂ and SUHI at night. The SO₂ values increased from very low to 330 μm mol/m2,and the SUHI nighttime values increased by approximately 4.8 °C. From the spatial point of view, this study also shows how the effects on such parameters shifted based on the urban form and land types across the City of Melbourne by using satellite data as a significant resource to analyze the spatial coverage of these factors. The findings of this study demonstrate how air quality factors, SUHI, air temperature, and lighting energy consumption changed from pre-lockdown (2019) to lockdown (2020), offering valuable insights regarding practices for managing SUHI, lighting energy consumption, and air pollution.

Wind energy system integration can lead to adverse effects on modern electric grid so it is imperative to assess their dynamic performance before actual plant startup. Transmission system operators all over the world stress the need for a proper wind turbine generator model for dynamic performance as well as ancillary service assessments. Due to the bulk power system assessment requirements, development of suitable generic modeling has gained high priority. Generic modeling of type 4 full converter wind turbine generator system for application in frequency ancillary service investigations under varying wind speed and varying reference power has been presented in this study. Prevalent generic model, manufacturer specific proprietary generic model along with detailed wind turbine model with synchronous generator is also provided to highlight various modelling framework difference. Descriptions of individual sub models of proposed generic model are presented in detail and performance results are compared and validated with GE’s proprietary generic model and detailed WTG model by means of simulations in the MATLAB® Power System Block set.

Expeditious urbanization, population growth, and technological advancements in the past decade have significantly impacted the rise of energy demand across the world. Mitigation of environmental impacts and socio-economic benefits associated with the renewable energy systems advocate the higher integration of the distributed energy systems into the conventional electricity grids. However, the rise of renewable energy generation increases the intermittent and stochastic nature of the energy management problem significantly. Therefore, an optimal energy management technique is required to achieve a high level of system reliability and operational efficiency. A state-of-the-art systematic review of the different optimization techniques used to address the energy management problems in microgrids is presented in this article. The different optimization techniques used in energy management problems, particularly focusing on forecasting, demand management, economic dispatch, and unit commitment, are identified and critically analyzed in this review. The inferences from the review indicated that the mixed integer programming techniques were widely used, considering their simplicity and performance in solving the energy management problem in microgrids. The multi-agent-based techniques and meta-heuristics algorithms outperformed the other conventional techniques in terms of the efficiency of the system due to the decentralized nature of the EMS problem in microgrids and the capability of these techniques to act effectively in such scenarios. In addition, it was also evident that the use of advanced optimization techniques was limited in the scope of forecasting and demand management. Advocating the need for more accurate scheduling and forecasting algorithms to address the energy management problem in microgrids. Finally, the need for an end-to-end energy management solution for a microgrid system and a transactive/collaborative energy sharing functionality in a community microgrid is presented.