Electrical Energy Conversion Systems Research Articles

Case study: Design and properties of acoustic energy harvester

Converting acoustic energy into electric energy can not only suppress environmental noise but also provide energy supply, which is a potential way to solve the bottleneck problem of energy supply in wireless sensor networks (WSNs). An acoustic energy harvester structure and circuit system combining Helmholtz resonance effect with piezoelectric effect are proposed in this article. The band gap characteristics of the designed acoustic energy harvester are analyzed by plane wave expansion (PWE) theory and experiment. The substrate of Helmholtz resonator is made from piezoelectric sheet, and the acoustic energy harvester structure is arranged periodically. When the incident noise frequency keeps coincidence with the resonant frequency, the conversion efficiency goes high up to 21.3%. The influence of series and parallel connection of piezoelectric elements on the acoustic to electric energy is observed. The AC-DC conversion circuit is designed with rectifier bridge, and the energy storage circuit is designed with supercapacitor. The power obtained from the acoustic to electric energy conversion system is 1523 mW. Application tests indicate that the noise suppresses, energy conversion, and energy storage can be realized at the same time by the proposed acoustic energy harvester system.

Utilization of Single Phase Pure Sine Wave Inverters in Electrical Energy Conversion Systems for Solar Panels with Variable Loads

The inverter built in this research is used to convert direct current into alternating current with a size of 3000 watts, which has a DC input voltage of 24 volts. This inverter has a large capacity and can generate enough electricity to run different huge electrical devices or several units at once. It's made utilizing energy-efficient technology to cut down on energy waste during conversion. Furthermore, safeguards such voltage surge and overcurrent prevention guarantee the operational safety of the inverter. The inverter was built using the PWM method and variable loads (resistive load, inductive load and capacitive load), with the aim of evaluating the inverter's ability to handle resistive, inductive and capacitive loads and to see how the inverter responds to load changes dynamically. Based on observations and calculations, higher loads are positively correlated with higher inverter power and efficiency. The inverter has a max output of 664.62 watts and 229 Volt is the output voltage attained. This demonstrates that the EGS002 PSW inverter produces AC voltage of high quality with precise and steady characteristics.

Nanowires based solid-state asymmetric self-charging supercapacitor driven by PVA–ZnO–KOH flexible piezoelectric matrix

The development of an efficient mechanical to electric energy conversion system and its functional integration with an energy storage device for self-powered portable devices are advanced research fields. In the traditionalconfiguration, an additional energy harvesting device is connected with an energy storage device for developing a self-charging unit. As a result, large amount of energy is lost because of the external rectifiers. Moreover, this type of external circuit makes the system bulky and thus, limits the practical applications of such devices. In this work, nanoparticles of Zinc oxide (ZnO) are employed as a piezoelectric material, and are combined with an asymmetric device for developing a self-charging asymmetric piezo-supercapacitor. The developed asymmetric piezo-supercapacitor comprises of Ni and Mg-Co nanowires-based binder-free electrodes that were employed as the anode and cathode, respectively, as well as a ZnO-based separator as energy harvester along with KOH as electrolyte. The electrochemical results reveal tremendous cyclic stability with capacitive retention of 100% and 96.5% for Mg-Co and Ni nanowires array based electrodes even after 10,000 repeated GCD cycles, respectively. In addition, the device attained a maximum voltage of ∼99 mV as a result of the compressive force via thumb press. The proposed facile as well as cost-effective approach for smart self-chargeable power package supercapacitor provides new insights for developing next generation all-in-one energy harvesting and storage devices.

Development and Experimental Validation of a Reduced-Scale Single-Phase Modular Multilevel Converter Applied to a Railway Static Converter

With special emphasis in recent years, an increase has been verified not only in demand but also in the price of electricity, arising the need to develop more reliable and efficient electrical energy conversion systems. In this context, emerges the utilization of the modular multilevel converter (MMC) based on submodules. The key to the MMC is modularity, which allows the converter to reach higher performance levels, improving the voltage and current output signals of the converter, in a compact solution. The modularity concept allows the increase of the operation voltage using submodules in series, and the increase of the operating current using submodules in parallel. Additionally, in the event of a submodule malfunction, the converter can be reconfigured and continue the operation, albeit at a lower power level. Due to its versatility, the MMC can be used in a variety of applications, such as HVDC power transmission systems, solid-state transformers, renewable energy interfaces, and more recently, railway power systems. In this context, this paper focuses on the development and experimental validation of a single-phase MMC based on the use of half-bridge submodules applied to a railway static converter, where the main focus lies on the AC side control. The control algorithms are fully described for a single-phase MMC reduced-scale prototype implemented (500 W, 230 V–50 Hz, 200 VDC), connecting two submodules in series in the upper arm, two submodules also in series in the lower arm, the respective driver and command circuits, sensing and signal conditioning circuits, as well as a digital control platform recurring to the DSP TMS320F28379D. Experimental results were obtained to validate each submodule individually, and, later, to verify the operation of the MMC with the set of four submodules.

Power distribution system for Xiangshan Internet of Underwater Things

The Xiangshan Internet of Underwater Things was successfully deployed in Xiangshan in September 2022, which is the first multi-node constant current cabled observatory network in China. Instead of being a real scientific IOT, the main motivation of this network is to verify the main energy conversion technologies applied in the Internet of Underwater Things, including multi-module-stack architecture electrical energy conversion system, digital branch unit, and fast deployable in-cable submarine observation node. The experiments verified that the system can guarantee the reliability and high efficiency of the Internet of Underwater Things.

ИССЛЕДОВАНИЕ ПОВЫШАЮЩЕГО ПРЕОБРАЗОВАТЕЛЯ ПОСТОЯННОГО НАПРЯЖЕНИЯ НА БАЗЕ МНОГОФУНКЦИОНАЛЬНОГО ИНТЕГРИРОВАННОГО ЭЛЕКТРОМАГНИТНОГО КОМПОНЕНТА

The relevance The methods of functional integration of discrete electrical and electromagnetic components allow increasing the reliability and efficiency of electrical energy conversion systems, reducing their weight and dimensions. The authors proposed a circuit solution based on the replacement of some individual discrete components of a DC boost converter with a multifunctional integrated electromagnetic component (MIEС). The component performs the functions of an inductor and a filter capacitor. Aim of research This article discusses the investigation of a DC voltage booster converter based on a multifunctional integrated electromagnetic component. The main task is to investigate a DC voltage booster converter based on a multifunctional integrated electromagnetic component. Research methods In this study, the following methods were used: the study of scientific literature and computer simulation in the Matlab environment. Results A computer model of a step-up DC voltage converter based on MIEС in the Circuit Simulator software package has been developed. Graphs of the output voltage are obtained. The circuits of step-up DC voltage converters are analyzed. A circuit of a DC voltage boost converter based on MIEС has been assembled. Output voltage waveforms were taken. An analysis of the computer model and laboratory test sample was carried out. A set of works has been completed to improve the output characteristics of a step-up converter based on MIEС. The optimal scheme has been chosen to implement the replacement of the inductor and filter capacitor with a multifunctional integrated electromagnetic component. Conducted laboratory studies confirmed the operability of MIEС as a replacement for individual discrete components of the DC voltage boost converter circuit. The optimal mode of operation of the boost converter based on MIEС is determined, which makes it possible to expand the output voltage range and reduce ripples. Expansion of the output voltage range is feasible due to the near-resonant or resonant mode of operation of the converter, which is feasible due to the MIEС structure, which is a resonant LC circuit.

Simulation studies of the existing cogeneration system and alternative conceptions to improve the energy efficiency for an ethylene petrochemical plant

Energy efficiency is relevant for the competitiveness and growth of global industries. In this way, simulation studies aiming to increase energy efficiency can be useful for both retrofitting and greenfield projects. Few ethylene process licensors hold the technologies; however, they present different proposals for projects with varying energy efficiency and integration degrees. In the present work, simulation studies of the cogeneration system of a petrochemical plant located in Brazil were performed in order to identify alternative configurations to increase the electricity production without affecting the heat supply to meet the process thermal demand. The cogeneration system of the analyzed plant includes an electric energy conversion system composed of turbo-generators, back-pressure and extraction/condensing steam turbines driving electricity generators, compressors and pumps, and heat exchangers. The simulation studies were performed using the HYSYS software to simulate design conditions and validate the model with the actual plant's experimental measurements. New cogeneration configurations were proposed in subsequent simulations, aiming at increasing electricity generation. In addition, exergetic efficiency and environmental analysis of the simulated configurations and an economic estimate for the most efficient proposal were performed. The results showed that the best alternative improved the electricity generation, increased the energy utilization factor by up to 16.2%, reduced greenhouse gas emissions by 22.8%, increased global exergetic efficiency by 28.9% and decreased the steam production and cold utility consumption of the cogeneration system compared to the design conditions.

Investigation of a DC voltage boost converter based on a multifunctional integrated electromagnetic component

The methods of functional integration of discrete electrical and electromagnetic components allow to increase the reliability and efficiency of electrical energy conversion systems, to reduce their weight and dimensions. The authors proposed a solution based on replacing some individual discrete components of a DC voltage boost converter with a multifunctional integrated electromagnetic component (MIEC). The component acts as an inductor and filter capacitor. A computer model of a DC voltage boost converter based on MIEC in the MatLab software package has been developed. The graphs of the output voltage are obtained. The circuits of step-up converters of constant voltage are analyzed. The optimal for the implementation of the replacement of the inductor and the filter capacitor with a multifunctional integrated electromagnetic component has been chosen. A circuit of a DC voltage boost converter based on MIEC is assembled. Oscillograms of the output voltage were taken. The analysis of the computer model and laboratory test sample was carried out.

A novel 7-Level symmetric inverter module with less circuit components

Multilevel Power Converters (MPCs) have vast potential in power electronics research and development of DC-AC electrical energy conversion system. MLIs have become an inescapable power electronics device in various power conversion applications due to the incompatibility of traditional two-level inverters. MLIs are extremely popular for medium power and high AC voltage applications, and thus predicted to gather incessant attention in future. This article suggests a novel single-phase symmetric 7-level inverter suitable for a renewable energy application with an effort to lower the count of switching components and conducting devices in the path for the flow of current. The proposed symmetric type inverter circuit could produce 7-level output voltage by using three DC sources and seven power electronic switches. The suggested inverter structure can be used to generate any number of voltage levels, and it can produce all output voltage levels (i.e.,+ve,-ve and zero), which significantly reduces the inverter's total standing voltage. The performance of the suggested 7-level inverter topology was confirmed by simulation results obtained in MATLAB/Simulink.

Electrothermal Model of Coupled Inductors with Nanocrystalline Cores

The paper proposes a new electrothermal model of a coupled inductor containing a nanocrystalline core dedicated to the analysis of electrical energy conversion systems. The formulated model has a form of a subcircuit for SPICE. The model takes into account the influence of direct current, frequency, skin effect, temperature, self-heating, and mutual thermal couplings on the parameters and characteristics of the coupled inductors. The form of the developed model and the method of model parameter estimation are presented. The applied measuring system is presented. The results of measurements and calculations made with the use of the proposed model are presented and commented on.

Implementation of Digital Twins for electrical energy conversion systems in selected case studies

Implementation of Digital Twins for electrical energy conversion systems in selected case studies

DESAIN DAN IMPLEMENTASI SECOND ORDER GENERALIZED INTEGRATOR-PHASE LOCKED LOOP (SOGI-PLL) UNTUK TEGANGAN SATU FASA MENGGUNAKAN DSPIC30F4011 DENGAN KONTROL PROPORTIONAL INTEGRAL

Grid Side Converter (GSC) is a power converter device that have important role in electrical energy conversion systems especially in the utilization of renewable energy sources in order to be connected to the grid. Based on the grid connection requirements, the GSC should be able to operate even if the grid is experiencing interference. Based on the problem, the GSC control system technically should have ability to detect grid disturbances quickly by using Phase Locked Loop (PLL) method that can provide grid voltage information. Compared with other PLL algorithms, the Second Order Generalized Integrator-Phase Locked Loop (SOGI-PLL) has adaptive-filtering characteristics in adjusting phase information. The SOGI-PLL method in this final project will be implemented for single phase system using dsPIC30F4011 microcontroller with PI controller. PI controller is expected to make the system has a fast response to the changes that occur, because the purpose of the PLL’s own needs is to get the results of grid voltage information such as magnitude, frequency, and phase in realtime. As the results, the SOGI-PLL algorithm through the use of ZMPT101B sensor shows the magnitude, frequency, and phase information is suitable with the grid voltage. The result of phase estimation have also been implemented in the inverter product development project, so that the output voltage inverter is in phase with the grid voltage.

Electric energy converter development and diagnostics in mixed-signal simulation environment

<p class="Abstract"><span lang="EN-US">In this work the input and output capacitors of a digitally controlled Buck converter have been tested in 4 different cases with unused and worn out capacitors. The information extracted from interactions between the subsystems of an electric energy conversion system requires the implementation of the whole system from network to load. A complex simulation environment has been implemented where digital and analogue domains can be connected. The input and output capacitor aging have a significant influence on time domain characteristics, but the evaluation of frequency-domain data is supposed to be required to extract information from the noisy and distorted time-domain signal. The presented diagnostic approach aims to analyze signals that are used by the control loop in order to avoid expensive additions to existing circuits.</span></p>

Probing the Cost-Effective Sodium Doped Strontium Silicate (Sr1-xNaxSiO3-0.5x) as Solid Electrolytes for IT-SOFC

The urgency for clean and secure energy has stimulated a global resurgence in searching foradvanced electrical energy conversion systems. Solid oxide fuel cells (SOFC) have been considered as one of the most promising electro-chemical energy conversion technologies due to their high efficiency, low emission, and excellent fuel flexibility. The most widely used electrolyte materials are fluorite structured yttria stabilized zirconia (YSZ). However, use of YSZ is limited because of the limiting magnitude of the electrical conductivity and its high operating temperature over 800 °C. Recently, the sodium doped strontium silicate (Sr1-xNaxSiO3-0.5x) is gathering attentions as a fast ion conductor [1]. And Wei et al. confirmed a good SOFC performance using this electrolyte material at 500 and 600 °C [2]. In this study, we investigated this promising material to get the optimal fabrication conditions with composition and to minimize degradation problems and also enhance the stability on this material. From this study, we found out the optimal fabrication conditions (sintering at 900 °C for 10 h) for 40 % sodium doped strontium silicate electrolyte which was known as the best ionic conductor. Thermal behaviour of the compositions has also been investigated for the applicability as solid electrolyte. Moreover, for the higher doping concentration (>40 %); a decrease in the electrical conductivity is observed. This decrease in the conductivity may be due to the formation of impurity phases of sodium silicate. Keywords: SOFC; Electrical conductivity; solid electrolyte; strontium silicate.

Transformer Less High Voltage Gain Step-Up DC-DC Converter Using Cascode Technique

The objective of this work is to achieve high step-up voltage gain with appropriate duty ratio with the application of cascode technique on buck boost converters for electric energy conversion system. As the available electrical AC voltage cannot be directly fed to electronic power devices, these devices and load require DC Power conversion from AC voltage sources. Conventional boost converters are unable to provide high voltage gains due to the effect of power switches, the impact of the parasitic resistive components and the reverse-recovery problem of the diodes. In this paper high voltage gain step-up (HVGSU) DC-DC converter is proposed, which consists of two integrated buck-boost converters with a single switch. High voltage gain can be achieved using cascode technique without any extreme duty ratio, here the duty ratio of the switch is controlled using PWM technique. The simulation and hardware of the proposed converter is discussed in detail.

A novel proton exchange membrane fuel cell based power conversion system for telecom supply with genetic algorithm assisted intelligent interfacing converter

This paper presents the fuel cell based simple electric energy conversion system for supplying the telecommunication towers to reduce the operation and maintenance cost of telecom companies. The telecom industry is at the boom and is penetrating deep into remote rural areas having unreliable or no grid supply. The telecom industry is getting heavily dependent on a diesel generator set and battery bank as a backup for continuously supplying a base transceiver station of telecom towers. This excessive usage of backup supply resulted in increased operational expenditure, the unreliability of power supply and had become a threat to the environment. A significant development and concern of clean energy sources, proton exchange membrane fuel cell based supply for base transceiver station is proposed with intelligent interfacing unit. The necessity of the battery bank capacity is significantly reduced as compared with the earlier solutions. Further, a simple closed loop and genetic algorithm assisted controller is proposed for intelligent interfacing unit which consists of power electronic boost converter for power conditioning. The proposed genetic algorithm assisted controller would ensure the tight voltage regulation at the DC distribution bus of the base transceiver station. Also, it will provide the robust performance of the base transceiver station under telecom load variation and proton exchange membrane fuel cell output voltage fluctuations. The complete electric energy conversion system along with telecom loads is simulated in MATLAB/Simulink platform and verified theoretically. The successful implementation and the obtained results illustrate the feasibility of the proposed system for reliable operation of the telecom towers.

Real-Time Optical Monitoring of Pt Catalyst Under the Potentiodynamic Conditions.

In situ monitoring of electrode materials reveals detailed physicochemical transition in electrochemical device. The key challenge is to explore the localized features of electrode surfaces, since the performance of an electrochemical device is determined by the summation of local architecture of the electrode material. Adaptive in situ techniques have been developed for numerous investigations; however, they require restricted measurement environments and provide limited information, which has impeded their widespread application. In this study, we realised an optics-based electrochemical in situ monitoring system by combining a dark-field micro/spectroscopy with an electrochemical workstation to investigate the physicochemical behaviours of Pt catalyst. We found that the localized plasmonic trait of a Pt-decorated Au nanoparticle as a model system varied in terms of its intensity and wavelength during the iterations of a cyclic voltammetry test. Furthermore, we show that morphological and compositional changes of the Pt catalyst can be traced in real time using changes in quantified plasmonic characteristics, which is a distinct advantage over the conventional electrochemistry-based in situ monitoring systems. These results indicate the substantial promise of online operando observation in a wide range of electrical energy conversion systems and electrochemical sensing areas.

Capillarity Based Ion Concentration Polarization for Desalination and Energy Harvesting

Ion Concentration Polarization (ICP) phenomenon is a traditional electrochemical ion transportation process near perm-selective membrane and appears as a steep concentration gradient under d.c. bias. The major function of ICP is an active ion control by an external electric field so that it is significantly useful to study the new ion transportation through nanoporous junction (or membrane) and develop novel engineering applications such as biomolecular preconcentrator and electro-desalination. Currently, the inherent capillarity of the nanostructure was demonstrated to initiate the same ICP phenomenon instead of an external power source so that a power-free desalination was achieved. This capillarity ion concentration polarization (CICP) device is shown to be capable of desalting an ambient electrolyte more than 90% without any external electrical power sources (Figure A). Theoretical analysis for both static and transient conditions are conducted to characterize this phenomenon. These results indicate that the CICP system can offer unique and economical approaches for a power-free water purification system in resource limited settings. As a reverse process of CICP, the chemical to electrical energy conversion system was successfully demonstrated as well. Since a convective flow near the perm-selective membrane plays a deterministic role for the ion transportation in both CICP and ICP mechanism, micro-pillar structures that enhance the convective flow around the membrane would accelerate the ion flux leading higher electrical current with the micro-pillar structure (Figure B). These microfluidic visualization platforms are significantly useful in both desalination and energy harvesting applications since it would provide a differential shell of such macroscopic systems that most of important ion exchanges occur microscopically. Figure A. Desalination using CICP mechanism. Figure B. current – time relation in ICP energy harvesting with and without micro pillar structures. Figure 1

Analysis of Integrated Electrical Wind Energy Conversion Systems

Some features of development of wind energy utilization in the world, the main problems of electrical wind energy conversion in integrated power units and analysis of existing wind energy conversion systems are presented in this paper.

Activation Barriers Provide Insight into the Mechanism of Self-Discharge in Polypyrrole

Conducting polymers are envisioned to play a significant role in the development of organic matter based electrical energy conversion and storage systems. However, successful utilization of conducting polymers relies on a fundamental understanding of their inherent possibilities and limitations. In this report we studied the temperature dependence of the self-discharge in polypyrrole and show that the rate of self-discharge is kinetically controlled by a polymer intrinsic endergonic electron transfer reaction forming a reactive intermediate. We further show that this intermediate is intimately linked to a process known as overoxidation. This process is general for most, if not all, p-doped conducting polymers irrespective of medium. The results herein are therefore expected to significantly impact the development of future energy storage systems with conducting polymer based components.