Electrical Conversion Research Articles

Distributional Consequences of Policies for Electric Heat Conversion

Distributional Consequences of Policies for Electric Heat Conversion

Simulation and Experiments on Optimization of Vortex-Induced Vibration Power Generation System Based on Side-by-Side Double Blunt Bodies

In order to improve the utilization efficiency of converting low-flow current energy into electric energy for Reynolds number 10,000 ≤ Re ≤ 40,000, this paper proposes a vortex-induced vibration power generation system based on a side-by-side double blunt body. In this system, the side-by-side double blunt body structure is used in the current energy capture part to enhance the collection of low-flow current energy; the permanent magnet linear motor is used in the electric energy conversion part to improve the efficiency of electric energy conversion; and a laboratory device is constructed for testing. The effects of the blunt body structure parameters and the center spacing ratio on the energy harvesting performance of the system are qualitatively explained by constructing a simulation model. Compared with the single blunt body energy capture structure, the side-by-side double blunt body structure increases the vibration amplitude by 1.04 times and the lift by 1.14 times at the center spacing S/D = 2.4. Meanwhile, energy harvesting can be realized at a lower flow velocity, increasing the vortex-induced vibration’s energy capture range. Finally, the power generation system was experimentally verified in the laboratory, and the results showed that the vibration amplitude of the double blunt body structure was increased by 1.12 times compared to the single blunt body. The maximum output power of the generator is 10.55 W when the water velocity is 0.7 m/s. The energy conversion efficiency of the power generation system can reach a maximum of 52.93%, which is 12.33% higher than that of a single blunt body structure, which proves that the system has a higher power conversion efficiency than that of a conventional single conversion system.

Synergetic Combination of Bio‐Electrolytes and Bio‐Fluidic Channels as a Novel Resource of Sustainable Energy

AbstractExploration for sustainable energy resources is essential to minimize the dependence on fossil fuels and to improve environmental parameters. Here, the possibility of utilizing bio‐waste‐derived electrolytes as an electrical energy resource by placing them across semipermeable membranes prepared through parallel stacking of coir fibers is examined. The nanofluidic membrane (d‐CF‐V) prepared by modifying the inner walls of the bio‐fluidic channels with atomically thin layers of vanadium pentoxide (VO) shows excellent perm‐selectivity (t+ = 0.87, with 1000‐fold concentration difference) and electricity conversion efficiency (≈ 28.2%). With simulated sea and river water, the d‐CF‐V yields output energy up to 2.4 W m−2, similarly with mineral acid bases (0.5 m HCl and 0.01 m NaOH), the d‐CF‐V shows an energy output of 11.8 W m−2. The sun‐dried Garcinia morella (Kuji thekera), and charred peels of Musa balbisiana (banana) are used as sustainable sources of bio‐electrolytes, which in combination with permselective d‐CF‐V yielded a power density of ≈1.4 W m−2. By replacing standard Ag/AgCl electrodes with nanomaterials exhibiting contrasting charge transfer activities, oxidized carbon nanotube membrane (o‐CNT) and polyaniline (PANI) membrane the output voltage is enhanced from –127 to –568 mV and current output is increased from 10.2 to 51.5 µA.

Comprehensive study on phase stability of lead-free Sn-based perovskite FAxMA1-xSnI3

Perovskite solar cells have become the most important devices for solar power to electricity conversion. However, currently, high-efficiency perovskite solar cells still rely on the use of Pb, which is harmful to the environment. Seeking environmentally friendly perovskite solar cells is imperative, and Sn is the most effective substitute for Pb. However, Sn-based perovskites face challenges due to their brief lifespan and rapid degradation, underscoring the need to improve their phase stability - a problem with still unclear mechanisms. This study addresses this by adjusting the ratio of formamidinium to methylammonium (FA/MA) in FAxMA1-xSnI3, experimentally finding optimal stability in phase composition and photoluminescence intensity at a ratio where x = 0.75. Using Density Functional Theory (DFT) and a pre-trained, fine-tuned machine-learning model, we explore the favorable molecular structures and configurations within FAxMA1-xSnI3. We discover that the FA0.75MA0.25SnI3 composition exhibits the lowest valence band maximum, indicating minimal oxidation tendency. Further DFT calculations of mixing and formation energies confirm that this composition is the most stable, aligning well with experimental observations and elucidating the underlying mechanisms of phase stability in Sn-based perovskite solar cells.

Phosphorus and Nitrogen Dual-Doped Hollow Porous Carbon Spheres toward Enhanced Cycling Stability of Room-Temperature Na-S Batteries.

Development of room-temperature sodium-sulfur (RT Na-S) batteries with satisfactory cycling life and rate capability remains challenging due to the unfavorable electric conductivity from S species, sluggish redox kinetics of S conversion, and serious shuttle effects of sodium polysulfides (NaPSs). To address these issues, a phosphorus and nitrogen dual-doped hollow porous carbon sphere (PN-HPCs) is synthesized as the S hosts, which enhances the electric conductivity, ion diffusion, and conversion of polysulfides. Such a hollow hierarchically porous structure is beneficial to accommodate the volume variations of S species and shorten the ion/electron transfer distances during electrochemical reaction process. As a result, the S@PN-HPCs600 cathode delivers noticeable cycling performance (313 mAh g-1 after 4500 cycles at 5.0 C, and capacity degeneration of only 0.01% per cycle) and rate capability (646.4 mAh g-1@1.0 and 527.5 mAh g-1@3.0 C). This work presents an efficient strategy based on structural confinement and dual-heteroatom doping engineering for long-life RT Na-S batteries.

Energy harvesting from a fiber-constrained dielectric elastomer generator embedded into a novel floating wave energy harvester

Abstract With the increasing energy demand and growing concern about greenhouse gases emissions from fossil fuel combustion, converting the ocean wave energy into the electrical energy has emerged as a promising and sustainable solution. This paper proposes a novel floating ocean wave energy harvester based on the fiber-constrained dielectric elastomer generator (DEG) arrays and investigates the energy harvesting (EH) performance of the fiber-constrained DEG embedded into the harvester. A theoretical analysis model of the fiber-constrained DEG describing the free relaxation process is developed and verified by the existing experimental data. On this basis, the electrical energy and conversion efficiency of the fiber-constrained DEG are comprehensively analyzed under diverse system parameters, aiming to explore the feasible methods for performance improvement. Results show that both the electrical energy and conversion efficiency are enhanced by shortening the cycle period, boosting the output voltage, and increasing the time ratio of the rising segment in a cycle period. Variations of the electrical energy and conversion efficiency with the input voltage exhibit the non-monotonic behavior. In addition, at low input voltage, enlarging the maximum stretch ratio improves the EH performance, while at high input voltage, the overlarge maximum stretch ratio goes against the performance improvement. The average output power of the harvester with different lengths of rods in its displacement magnifying mechanism is also investigated. Results show increasing the rod length can improve the average output power. In addition, results can help to provide a guidance for designing a high-performance DE-based floating wave energy harvester.

Theoretical study of the strong piezo-phototronic effect in 2D monochalcogenides for multi-junction solar cells

The piezophototronic effect is a new scientific area that investigates the synergistic interactions of piezoelectric, semiconductor, and photoexcitation features. This effect is seen in crystals lacking inversion symmetry, where applied strain alters electronic transport and provides a way to modify material properties. Monolayer 2D semiconductors, such as transition metal dichalcogenides (TMDCs) and group IV monochalcogenides, have higher piezoelectric coefficients than conventional piezoelectric materials. This study proposes the development of a stable, high-performance multijunction solar cell (MJSC) leveraging the piezo-phototronic effect. The emphasis is on single-type 5-layer 2D monochalcogenides (SnS, SnSe, GeS, and GeSe) with the assistance of strain engineering. Surprisingly, the ultrathin parallel-connected solar cell achieves an electric power conversion efficiency of over 31% when tested under blackbody radiation, surpassing the recognized Shockley–Queisser (S-Q) limit. The piezophototronic effect improves solar cell performance while also addressing voltage mismatch issues. This work introduces a novel approach to developing and manufacturing high-efficiency and robust monolayer multijunction photovoltaic solar cells (MJPSC) based on 2D monochalcogenides.

An optimal scheduling strategy for electricity-thermal synergy and complementarity among multi-microgrid based on cooperative games

Multi-microgrid (MMG) systems provide an effective way to convert renewable energy into other forms of energy for low-carbon utilization. However, the coupling of multi-energy and renewable energy brings a challenge to the stable operation and dispatch of the system. Therefore, an electricity-thermal-gas-hydrogen MMG complementary optimization model based on peer-to-peer (P2P) electricity-thermal synergy is proposed. The model focuses on the coupling and conversion of electricity, hydrogen, and thermal through a hydrogen energy storage system (HESS) combined with renewable energy, and incorporates integrated demand response (IDR) and ladder-type carbon trading mechanism (LCTM). Subsequently, based on the cooperative game and the alternating direction multiplier method (ADMM), a multi-energy synergistic and complementary optimal scheduling strategy is proposed, which increases the flexibility of multi-energy sharing. In addition, a revenue allocation optimization strategy that takes into account the fairness and renewable energy consumption rate is proposed to achieve the stability of the alliance system operation. Finally, the simulation results show the effectiveness of the proposed model and strategy, realizing the complementary sharing of regional multi-energy, enabling the expansion of the boundaries of optimal energy allocation, further improving the low-carbon economic operation capability of MMG, and reducing the dependence of the system on the energy market.

Effects of wire rope isolators on seismic life-cycle cost of UHV bypass switch

The seismic isolation devices reduce the seismic vulnerability of the electrical equipment. Accurately assessing the seismic life-cycle cost (SLCC) of the electrical equipment is beneficial in guiding the design and enhancing the seismic resilience of electrical substations and converter stations. To evaluate the effects of the isolator devices on the seismic life-cycle cost of electrical equipment, a SLCC evaluation model was proposed in this study, and the evaluation was conducted on an ultra-high voltage (UHV) bypass switch (BPS) with wire rope isolators (WRI). The model takes into account equipment purchase, maintenance, transportation and installation costs and indirect losses caused by power outages. Afterward, the SLCC and break-even time of the UHV BPS with and without WRIs in different regions were analyzed. The results indicate that beyond the break-even time, the BPS with WRIs becomes more economically viable. Moreover, its economic viability increases as the service life extends. Therefore, in high seismic cost risk areas, it is recommended to adopt seismic isolation devices to ensure the secure and economically efficient operation of electrical equipment.

Comparative experimental analysis of monocrystalline and polycrystalline photovoltaic panel through hybrid phase change material

Photovoltaics thermal management is utmost necessary as continuous heating of the module decreases the performance. This paper presents a comparative study in terms of performance of two photovoltaic modules namely monocrystalline and polycrystalline using hybrid phase change materials (PCMs). The hybrid PCMs of RT31 and RT 44HC were prepared by method of stirring. The final prepared hybrid PCMs were poured at the back of panel and panel was covered. The purpose of these experiments is to improve the efficiency of polycrystalline and monocrystalline photovoltaic modules and comparing which technology is more efficient having hybrid PCM. The experiments were performed under the room conditions in Taxila, Pakistan. The output parameters of the photovoltaic module appeared to be strongly dependent upon the solar irradiance. The power output and efficiency of monocrystalline and polycrystalline photovoltaic module were measured. The monocrystalline panel maximum temperature was 36.59 °C as compared to polycrystalline panel which was 40.23 °C. As the radiation intensity increased till noon, electrical power was improved, and it was 6.52 W in monocrystalline panel as compared to polycrystalline panel which was 6.32 W. Electrical conversion efficiency was also observed, and it was maximum up to 11.84 % in monocrystalline panel. The higher performance was observed in case of monocrystalline panel having hybrid in terms of performance as compared to polycrystalline panel.

Digital Active EMI Filter for Smart Electronic Power Converters

Electronic power converters are widespread and crucial components in modern energy scenarios. Beyond mere electrical energy conversion, their electronic structure allows several functionalities to be naturally embedded in them, including energy management, diagnosis, communication, etc. The operation of the converter itself, or the system interfaced by the same, commonly produces undesired electromagnetic interferences (EMIs) that should comply with prescribed limits. This paper presents a digital active EMI filter designed to mitigate such disturbances. The proposed hardware implementation can acquire and analyze the common-mode (CM) noise affecting the circuit and inject a compensation signal to attenuate the measured interference. A novel adaptive algorithm is introduced to compute the necessary signals for effective noise cancellation. The implementation is integrated within a single printed circuit board interfaced with a field-programmable gate array (FPGA) running the control algorithm. The digital filter’s efficacy in EMI reduction is demonstrated using a synchronous buck converter with gallium nitride (GaN) power devices, achieving significant noise reduction. Additionally, potential functionalities are envisioned to fully exploit the capabilities of the proposal beyond EMI filtering, like fault detection, predictive maintenance, smart converter optimization, and communication.

The barriers, determinants, and willingness-to-pay in electric motorcycle conversion (EMC) adoption

The rise in motorcycle use in Southeast Asian countries like Indonesia has caused environmental issues and transitioning from fossil-fuel to electric motorcycles (EM) will reduce emissions and improve air quality. This study aims to investigate the barriers, determinants, and willingness-to-pay in electric motorcycle conversion (EMC). In a choice experiment, data from motorcycle users in Bali, Indonesia, was collected and analysed in this study using K-modes cluster analysis and the Mixed-Logit Model. The study identified different barriers to EMC among motorcyclist groups: mix-motor commuters and hardcore oldies concerned with financial challenges, all-day riders with mature motorcycles face a lack of information on EMC costs and procedures, and higher-power enthusiasts and newbies with light motorcycles concerned with daily travel disruptions during the conversion process. This study also found waiting and conversion time to play a role in EM adoption and travellers who use older motorcycles are the most likely to adopt EMC. Lower-income individuals tend to be more inclined towards EMC and younger demographics lean towards internal combustion engine (ICE) motorcycles. Moreover, the study indicates that EMC reduces the adoption of ICE motorcycles more than conventional EM. A 50% increase in conversion time lowers EMC adoption probability by 5.2%pts. and increases new ICE motorcycle adoption by 3%pts. and new EM adoption by 2.2%pts. Additionally, motorcyclists are more willing to invest in EMC if it means reducing conversion time/charging costs, particularly for older motorcycles. This study offers several policy recommendations for accelerating EMC adoption in Indonesia.

Stochastic optimal scheduling of a combined wind-photovoltaic-CSP-fire system accounting for electrical heat conversion

Aiming at the consumption problem caused by the increasing scale of wind power and photovoltaic (PV) grid-connected, a multi-energy co-generation system is constructed with wind power, PV, concentrated solar power (CSP), and thermal power; in addition, in order to reduce the impact of the prediction errors of wind power, PV, and loads on the system’s economic operation, the photovoltaic and thermal power plants are used to provide the system's backup capacity together, and the opportunity constraint model of the reliability of the backup capacity is established, so as to satisfy the system reliability constraints at a certain higher confidence level; finally, a sampling-based deterministic transformation method is introduced to simplify the model. The model is simplified by introducing a sampling-based deterministic transformation method of opportunity constraint; finally, a stochastic optimal dispatch model of the combined wind-photovoltaic-CSP-fire system, which accounts for the conversion of electricity and heat, is constructed with the objective of minimising the integrated operating cost of the combined system, and the effectiveness of the proposed model is analysed by simulation verification.

Design of a Novel Hybrid Concentrated Photovoltaic–Thermal System Equipped with Energy Storages, Optimized for Use in Residential Contexts

Concentrated photovoltaic (CPV) technology is based on the principle of concentrating direct sunlight onto small but very efficient photovoltaic (PV) cells. This approach allows the realization of PV modules with conversion efficiencies exceeding 30%, which is significantly higher than that of the flat panels. However, to achieve optimal performance, these modules must always be perpendicular to solar radiation; hence, they are mounted on high-precision solar trackers. This requirement has led to the predominant use of CPV technology in the construction of solar power plants in open and large fields for utility scale applications. In this paper, the authors present a novel approach allowing the use of this technology for residential installations, mounting the system both on flat and sloped roofs. Therefore, the main components of cell and primary lens have been chosen to contain the dimensions and, in particular, the thickness of the module. This paper describes the main design steps: thermal analysis allowed the housing construction material to be defined to contain cell working temperature, while with deep optical studies, experimentally validated main geometrical and functional characteristics of the CPV have been identified. The design of a whole CPV system includes thermal storage for domestic hot water and a 1 kWh electrical battery. The main design results indicate an estimated electrical conversion efficiency of 30%, based on a cell efficiency of approximately 42% under operational conditions and a measured optical efficiency of 74%. The CPV system has a nominal electric output of 550 Wp and can simultaneously generate 630 W of thermal power, resulting in an overall system efficiency of 65.5%. The system also boasts high optical acceptance angles (±0.6°) and broad assembly tolerances (±1 mm). Cost analysis reveals higher unit costs compared to conventional PV and CPV systems, but these become competitive when considering the benefit of excess thermal energy recovery and use by the end user.

Analytical Conversion of Conventional Car to Electric Vehicle Using 5KW BLDC Electric Motor

The automotive industry is witnessing a paradigm shift towards sustainable and eco-friendly transportation solutions. This project aims to contribute to this transition by converting a conventional internal combustion engine (ICE) car into an electric vehicle (EV) using a 5 kW Brushless DC (BLDC) electric motor. The conversion involves the removal of the traditional engine components and the integration of an electric propulsion system. The key components of the conversion include the BLDC motor, motor controller, battery pack, and associated power electronics. The BLDC motor is chosen for its efficiency, reliability, and compact design, making it suitable for retrofitting into existing vehicles. The motor controller manages the power supplied to the BLDC motor, ensuring optimal performance and efficiency. The project explores the challenges and solutions encountered during the conversion process, including adapting the vehicle's chassis to accommodate the new components, integrating a charging system, and addressing safety considerations. Additionally, efforts are made to optimize the overall weight distribution and maintain the vehicle's original handling characteristics. Performance testing is conducted to evaluate the acceleration, top speed, and overall efficiency of the converted electric vehicle. The results are compared with the original performance specifications of the conventional car to assess the success of the conversion. This project not only showcases the technical feasibility of converting conventional cars to electric vehicles but also highlights the environmental benefits associated with reducing reliance on fossil fuels. The findings contribute valuable insights to the growing field of electric vehicle conversions and promote sustainable transportation solutions.

Taguchi Approach to Defect Analysis on Electric Motor Conversion at PT. Electric Vehicle Trimotorindo

Maintaining product quality can reduce the risk of defective products. The survival of a company is heavily reliant on product quality. In order to improve performance and reduce defects in the product process, PT. Electric Vehicle Trimotorindo employs the Taguchi approach in conjunction with the QC system. The goal of this research is to determine the product process of PT. Trimotorindo Electric Vehicle, identify the highest rejection rate, evaluate process capability, and propose improvements using the Kaizen system. This study uses the Taguchi system to optimize the product process of PT. Trimotorindo Electric Vehicles. After collecting data from the taguchi system, it can be concluded that the highest position of blights in a conversion process is in the electric current string.

Coupling between the photoactivity and CO2 adsorption on rapidly thermal hydrogenated vs. conventionally annealed copper oxides deposited on TiO2 nanotubes

AbstractHighly ordered spaced titanium dioxide nanotubes were fabricated via electrochemical anodization and modified with titania nanoparticles and copper oxides. Such materials were rapidly annealed in hydrogen atmosphere or conventionally in a tube furnace in air, in which the temperature slowly increases. Applied synthesis procedure can be considered as simple, cost-effective, and environmentally friendly as it allows for reduction in used materials and enhances sustainable engineering. Manipulating the chemical composition of materials by different thermal treatments resulted in various photoelectrochemical activities and density of CO2 adsorption sites. Rapidly annealed nanotubes decorated by copper oxides exhibit excellent electrochemical properties where one electrode combines both: solar to electricity conversion (photocurrent under visible light 30 µA/cm2) and CO2 adsorption systems (18 times higher current after CO2 saturation). Rapidly thermal hydrogenated TiO2 nanotubes with copper oxides had 17 times higher photocurrent and wider absorption band (380–780 nm) than conventionally annealed ones. Furthermore, the crystal planes such as Cu (111), Cu (220), Cu2O (110), CuO (002) and Cu0, Cu+, Cu2+ oxidation states, and oxygen vacancies were recognized for hydrogenated sample. It should be highlighted that thermal annealing conditions significantly affects ability of copper oxide to CO2 adsorption and CO2 reduction reaction for hydrogenated electrode. Graphical abstract

Fe-doped phosphide nanosheet array derived from prussian blue analogues for high-efficient electrocatalytic water splitting

Doping heterogeneous atoms can modulate electronic structure, which matters for creating efficient bifunctional electrocatalysts in realizing conversion of hydrogen and electricity. This study demonstrates that Fe-doped Ni5P4 nanosheet arrays on nickel foam (Fe–Ni5P4/NF) using Prussian blue analogues as precursors are successfully synthesized by straightforward hydrothermal reactions and phosphating. Fe–Ni5P4/NF exhibits great efficiency in creating hydrogen from water under alkaline conditions. The Fe–Ni5P4/NF dual electrode just need a minimal cell voltage of 1.54 V at 10 mA cm−2 and maintain operational stability for a minimum of 50 h, demonstrating outstanding bifunctional properties. The introduction of Fe modifies the electronic configuration for Ni5P4, substantially boosting the activity of the electrocatalyst. This study offers a framework for designing splendid bifunctional electrocatalysts through synergistic doping strategies in electrochemical applications.

Multi-field coupling analysis of photovoltaic cells under long distance and multi-mode laser transmission

Most electronic devices are powered by electricity, and the transfer of energy to related electronic devices is a critical issue. Laser wireless power transmission (LWPT) has a broad prospect in the field of wireless energy transmission, such as distributed charging system (DLC), spacecraft sensor network, satellite-to-satellite communication and medium and long distance power transmission, ground to unmanned aerial vehicle (UAV), and so on. In this paper, a multi-field coupled model of LWPT system for laser transmission at medium and long distances is established. Through the existing LWPT experimental platform and test, the test obtained the correlation coefficient of the I-V relationship formula with the change of light intensity and temperature. On the basis of the modified parameters, the attenuation efficiency of laser power with transmission distance is calculated, and the heat transfer and electrical characteristics of photovoltaic cells are solved by finite element method. It is found that different atmospheric environment and laser transmission distance have obvious effects on the voltage, current and temperature variation of photovoltaic cells. The temperature of a photovoltaic cell has a huge impact on its output efficiency. The temperature can be controlled effectively by setting the laser interval of pulse mode reasonably. The cooling capacity of photovoltaic cells is the key to improve the electrical conversion efficiency of LWPT systems.

Accounting for power take-off efficiency in optimal velocity tracking control of wave energy converters

There has been much research into how Wave Energy Converters (WECs) can capture energy from the waves and convert it into kinetic energy in the mechanical system (mechanical energy). However, because WECs typically generate power at high force and with low speed, the conversion of the mechanical energy into electrical energy can be inefficient. If Power Take-Off (PTO) efficiency is not accounted for in controller design then the efficiency of the WEC from wave energy to electrical energy can be poor. In this work, an adaptation of Optimal Velocity Tracking (OVT) control is presented, termed OVT-E, that accounts for PTO efficiencies in the controller formulation such that it converts more energy from the waves to electricity than traditional OVT approaches, termed OVT-M. Results show that, for an example WEC and PTO system in a simulation environment, OVT-E produces more efficient electrical energy conversion than OVT-M with lower forces through the drive-train. OVT-E is also shown to convert more electrical energy than an adaptive linear damping method. The methodology for designing OVT-E could have further applications when coupled with other controller implementations or if used alongside machine-learning for control co-design purposes.