In recent years, the integration of bidirectional converters in the grid for V2G (vehicle-to–grid) applications of Electric Vehicles (EVs) has gained significant attention due to its potential to enhance grid stability, energy efficiency, and economic benefits. This analytical review highlights the different topologies of bidirectional converters and discusses various control techniques for efficient power flow between the vehicle and grid to enhance the performance of V2G and G2V functionalities. Further, the topologies of bidirectional converters highlighting key parameters such as the count of switches and their voltage stress, current ripple, efficiency, etc., are explored. The distinct advantages and limitations of each classification are also discussed. Many multilevel topologies that generate significant gain with low stress on switches and lesser harmonics have also been reviewed. The review then examines various control strategies, including power flow control and voltage regulation. These techniques are classified according to their control methodologies, which include traditional proportional-integral (PI) control, predictive control, sophisticated model-based control, and optimization. The synthesis of current advances in bidirectional converters and control techniques sheds light on developing trends and technologies, identifying important problems and future research objectives in the field. The economic and environmental implications of the G2V and V2G case studies also reinforce the review. Thus, this evaluation aims to promote further breakthroughs in EV integration with the grid, eventually leading to a more sustainable and resilient energy ecology.
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.
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.
17 September 2021 in Australian Journal of Electrical and Electronics Engineering
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.
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.
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.