Shimi Sudha Letha

This paper examines the random nature of interharmonics generated by power converters connected to sustainable energy sources and loads, such as wind turbines, photovoltaic (PV) panels, and electric vehicles (EVs). Current research often overlooks the stochastic behavior of interharmonics and their impact on power system reliability and resilience, leading to gaps in effective modeling and mitigation strategies. Thus, this study examines a low-voltage installation with a PV panel, an EV and a microwave operating simultaneously, providing practical insights into real-world scenarios of interharmonic related disruptions and solutions for enhancing the reliability and resilience of sustainable energy grids. By leveraging real-time measurements of interharmonics, suitable probability distribution functions (PDFs) are initialized to develop a probabilistic model using Monte Carlo simulation. This enables the derivation of a time-domain aggregation model of interharmonics from multiple sources operating together at the point of common coupling (PCC). The findings reveal that the peak values of voltage or current fluctuations at the PCC are influenced by the randomness in the number of devices connected and the frequency components originating from different sources. Through multiple case studies, the dependency of these fluctuations on stochastic parameters is systematically established. Empirical relationships are formulated to predict aggregated interharmonic values under varying scenarios, enhancing the accuracy and applicability of the model. The results demonstrate that higher interharmonic frequencies and fewer randomly connected devices significantly increase the probability of elevated aggregated peak values. These insights can serve as benchmarks for grid operators and policymakers in mitigating interharmonic related issues in modern power systems.

Electric vehicles (EVs) are becoming increasingly popular, but their widespread adoption is still limited by issues such as short battery life and limited driving range. To address these challenges, this study proposes an intelligent current management strategy using a battery/supercapacitor hybrid energy storage system (HESS). The goal is to optimize current distribution, extend battery life, and improve overall energy efficiency. An algorithm is developed and tested using a hardware‐in‐the‐loop (HIL) emulation platform. Two intelligent controllers—based on artificial neural networks (ANN) and adaptive neuro‐fuzzy inference systems (ANFIS)—are designed and compared with a conventional rule‐based controller and an EV system without a supercapacitor (SC). The ANN and ANFIS controllers are trained using data from the rule‐based controller. The results show that the intelligent controllers, especially the ANFIS‐based controller, significantly improve battery capacity reduction and energy management. In the Federal Test Procedure 75 (FTP‐75) driving cycle, the ANFIS controller improved battery capacity by 13.27% at the 5000th cycle. In the European Driving Cycle (ECE‐15) cycle, the improvement was 3.05%. For the Extra‐Urban Driving Cycle (EUDC) cycle, the EV without a SC experienced 100% battery capacity loss by the 2000th cycle, while the ANFIS controller reduced this loss to 62.06% at the 5000th cycle. These findings confirm that the proposed ANFIS‐based controller is the most effective in preserving battery life and enhancing driving range. This approach offers a practical and efficient solution to key limitations in EV performance, contributing to the development of more reliable and longer‐lasting EVs.

Currently, multilevel inverters (MLI) are comprehensively used to integrate renewable energy sources with the grid or high‐power applications. MLI has outstanding properties such as high‐level output voltage with tremendous power quality and negligible harmonics distortion. General MLI topologies have a more complex circuit, high overall cost and installation area. Due to a large number of power switches and isolation of control circuit, fewer power electronic switches and DC source along with its suitable control logic is the need of the hour. Therefore, a lot of research scope exists in this area. Here, some of the topologies with a fewer number of power switches are reviewed and scrutinized. An extensive analysis of the topologies, control strategy and applications are presented here, suggesting suitable multilevel inverter solutions to the known industrial application or new research.

The modernization of the world is driving an increase in electrical power demand on the grid. Every year, the number of community buildings is rising across different cities. In India, the growth of village-based community culture also contributes to higher power demands. This study focuses on an off-grid community microgrid to provide power to villages. A simulation study is conducted using HOMER software, where the primary power source is a solar photovoltaic plant with battery storage, supported by an emergency backup source of a diesel generator set. An optimization technique is applied to integrate multiple power sources based on the community microgrid's demand

Multilevel inverters play a crucial role in high‐power renewable energy applications and medium voltage drives. However, existing solutions such as capacitor‐clamped and diode‐clamped multilevel inverters are not suitable for these applications due to their dependence on isolated DC sources, complex control techniques, and potential reliability issues. Here, a novel fifteen‐level inverter topology is proposed which addresses these limitations. The proposed multilevel inverters utilize a topology with reduced number of switches, which can effectively accommodate isolated DC sources. It consists of eight switches for level generation and four switches for polarity generation (H‐bridge). One of the key advantages of this topology is that it significantly reduces the Total Harmonic Distortion (THD) in accordance with the IEEE 519 standards. Genetic algorithm‐based selective harmonic elimination technique was employed for THD minimization. A detailed switching loss calculation and harmonic analysis were performed to support the effectiveness of the proposed topology and the control used. The implementation of the proposed topology is simple and straightforward. Furthermore, to validate the results, insulated gate bipolar transistor based hardware model was developed. The optimized firing pulses were generated using the dSPACE 1104 controller. The results were compared with the existing recent literature and was found to address the limitations of existing topology.

Light-emitting diode (LED) lighting has, compared to other types of lighting, a significantly lower energy consumption. However, the perceived service life is also important for customer satisfaction and here there is a discrepancy between customers’ experience and manufacturers’ statements. Many customers experience a significantly shorter service life than claimed by the manufacturers. An experiment was carried out in the Pehr Högström Laboratory at Luleå University of Technology in Skellefteå, Sweden to investigate whether voltage disturbances could explain this discrepancy. Over 1000 LED lamps were exposed to high levels of voltage disturbances for more than 6000 h; the failure rate from this experiment was similar to the one from previous experiments in which lamps were exposed to normal voltage. The discrepancy thus remains, even though some possible explanations have emerged from the project’s results. The lamps were exposed to five different types of voltage disturbances: short interruptions; transients; overvoltage; undervoltage; and harmonics. Only overvoltage resulted in failure of the lamps, and only for a single topology of lamp. A detailed analysis has been made of the topology of lamps that failed. This lamp type contains a different internal electronics circuit than the other lamp types. Failures of the lamps when exposed to overvoltage are due to the heat development in the control circuit increasing sharply when the lamps are exposed to a higher voltage. Hence, it is concluded that there are lamps that are significantly more sensitive to voltage disturbances than other lamp types. Manufactures need to consider the voltage quality that can be expected at the terminal of the lamp to prevent failure of lamps due to voltage disturbances. This paper therefore contains recommendations for manufacturers of lighting; the recommendations describe which voltage disturbances lamps should cope with.

Due to numerous shortcomings of the existing automobiles, the future of transportation lies in Electric Vehicles (EVs). For the sustainable existence of EVs, the development of charging infrastructure based on renewable sources is necessary. Hence, this research article aims to develop a PV–grid topology-based EV charger. An experimental prototype of the EV charging station (EVCS) is developed having a modified interleaved boost converter (MIBC). The proposed charger setup is tested by charging a PV on an EV with a Li-ion battery. The MIBC proposed is analysed and compared with the conventional boost converter, which is also based on PV-grid topology. The testing verifies that the current ripples, conduction and switching losses are reduced significantly. The results conclude that the prototype charger developed is robust, efficient and reliable.