Voltage Frequency Research Articles

Partial discharge inception voltage in PCB defect samples under different frequencies of alternating sine wave voltage

Abstract As the application of power electronic components in renewable and green energy technologies continues to increase, there is an increasing trend in the utilization of higher voltage and frequency levels. This shift may result in more frequent partial discharge (PD) phenomena that can accelerate the degradation of insulation materials and shorten the lifespan of the components. Therefore, it is critical to ensure the reliability and durability of these components. This study investigated the effects of voltage magnitude and frequency on the PD and insulation degradation of printed circuit board (PCB) samples. Five different test samples were fabricated using a PCB as the substrate and an epoxy resin as the insulating coating. Two distinct testing configurations were employed: one for assessments based on a commercial frequency (60 Hz) and the other for assessments based on a high frequency (600 Hz). This study examined the behavior of PD within PCBs and the resulting insulation deterioration. The results demonstrated that all the samples exhibited significantly lower PD inception voltages (PDIV) at high frequencies compared with those at the commercial frequency. Specifically, the maximum decrease in the PDIV observed was 5 kV, while the minimum reduction was 3.3 kV. These findings highlight the critical impact of frequency on the PD behavior and underscore the importance of understanding these effects to enhance the reliability of electronic components in high-frequency applications.

Voltage stability and frequency stability analysis of Zhejiang power grid

Voltage stability and frequency stability analysis of Zhejiang power grid

Online Feedback Droop Scheduling in Distribution Grids for Frequency and Local Voltage Control

Online Feedback Droop Scheduling in Distribution Grids for Frequency and Local Voltage Control

Study on Grid Stability of Electric Vehicle Bidirectional Charging Device Based on Bidirectional Power Electronic Converter

With the increasing number of electric vehicles (EVs), V2G (Vehicle-to-Grid) and G2V (Grid-to-Vehicle) technologies have garnered growing attention as essential methods for energy flow between EVs and the power grid. This study examines the impact of EV charging devices, based on bidirectional power electronic converters, on grid stability. As EVs become more widely adopted, V2G and G2V technologies are extensively applied to enable bidirectional energy flow between EVs and the grid. This study analyzes different topologies of power electronic converters and explores how optimized control strategies can enhance grid voltage and frequency stability. The research shows that bidirectional charging devices provide significant advantages in addressing voltage fluctuations and frequency instability, especially in peak shaving and valley filling, effectively easing grid load. Furthermore, future developments in bidirectional charging devices will focus on intelligent control and synergistic optimization with renewable energy to improve grid stability and power quality. The research methods include analysis and comparison of different converter topologies. Results indicate that bidirectional charging devices have a significant effect in resolving grid instability issues, supporting the further advancement of smart grids).

Mode transition in a helium barrier discharge with oxygen admixtures: insights into a micro cavity plasma array reactor

Abstract Dielectric barrier discharges (DBDs) offer great potential for applications such as volatile organic compounds (VOCs) conversion or plasma catalysis. For many of these applications, an admixture of molecular oxygen is important, for example, to oxidize the gases to be treated. However, oxygen addition can lead to a drastic change in discharge dynamics, which may affect conversion efficiency. The discharge may transition to a filamentary mode, which could influence plasma chemical processes or in extreme cases potentially damage the reactor. This study investigates the discharge mode of a micro cavity plasma array operated at atmospheric pressure with a helium flow (1–2 slm) containing small oxygen admixtures (0%–5%). A multitude of parameters as voltage, current, power, and emission are investigated for characterization. Additionally, the electric field, mean electron energy and atomic oxygen density are examined depending on the oxygen admixture. With pure helium, a homogeneous atmospheric pressure glow discharge is observed, appearing as a quasi-continuous glow discharge. With small oxygen admixtures (0.1%–1%), individual discharge pulses become visible, though they remain separated (pseudo glow discharge). At higher oxygen admixtures ( ⩾ 1%), a mode transition to a filamentary discharge is observed. The measurements indicate that the discharge mode, especially the individual discharge pulses, has a significant impact on conversion efficiency. This knowledge can help in the future to fine-tune the discharge mode using external parameters such as voltage waveform or frequency to optimize conversion efficiency.

WAVE INTERPRETATION AND NEURAL NET MONITORING OF NOISE IN VOLTAGE SIGNALS ON POWER LINES

Noise in voltage signals on power lines is determined by many factors. Therefore, at the standard sampling rate of signals in measuring instruments, it is considered, most often, to be Gaussian. At a high sampling rate, the noise is modulated, its distribution differs from the normal one. The analysis and control of its structure is of interest, for example, for damage diagnostics and determining the damage location. The purpose of the study is to show the possibility of neural network control of heterogeneous noise in voltage signals on power lines. Methods. Based on the wave analysis of signals in power lines, a noise model in industrial frequency voltage signals is described, which allows interpreting its modulation as a result of random spatial fluctuations in wave velocity. The control of noise heterogeneity over the harmonic signal period is carried out on the basis of a recurrent ANN in a sliding time window, the duration of which does not exceed 2 ms. Results. The noise model in power line voltage signals is proposed as a result of wave reflection from the wave velocity spatial inhomogeneities in the line. In the Born’s scattering approximation, noise is described by the simplest analytical formulas with random parameters. A neural network algorithm based on LSTM cells was tested on model signals recordings, which is used in a sliding time window and allows one to control the noise variance in units of percent of the industrial frequency signal amplitude. Estimates of the neural network algorithm accuracy are given. Conclusions. A comparison of the noise structure obtained using the proposed model with experimental signals recordings confirms the adequacy of the model at a qualitative level. The proposed neural network monitoring algorithm has high accuracy. The approach can be used to monitor the present state of power lines.

Corrosion Resistance and Structure of Cr−O−N Coatings Formed in Vacuum Arc Plasma Fluxes With PIIID

ABSTRACTCr−O−N‐based vacuum arc coatings are very promising for the wear and corrosion protection of various steel parts. The aim of the work was to determine the effect of frequency and amplitude of the pulsed bias voltage (UB) on the elemental and phase composition, mechanical, and corrosion properties of Cr−O−N coatings. They have an amorphous structure with embedded nanosized solid solution crystallites based on CrN with a cubic structure and Cr2O3 with a rhombohedral structure. The increase in the bias voltage results in a reduction in the grain size of the Cr2O3 and CrN phases by about four times to about 5 nm, as well as a change in the CrN phase content in the coating. The lattice parameter increases slightly for the Cr2O3 phase but decreases for the CrN phase. The increase in the pulse frequency results in an increase in the CrN phase content in the coating and the lattice constant of both phases and a slight decrease in the crystallite size. The hardness of Cr−O−N coatings slightly increased with the UB from 26 ± 1 GPa (DC) to 28 ± 1 GPa (−300 V, pulsed), and the elastic modulus ranges from 290 to 310 GPa. The greatest changes were observed in corrosion resistance. With an increase in the bias voltage and pulse frequency, the corrosion current of Cr−O−N coatings on steel in 3% NaCl solution decreased by three orders of magnitude compared to coatings deposited at DC voltage and by five orders of magnitude compared to the base steel. Therefore, the use of a pulsed bias voltage with a frequency of at least 10 kHz and an amplitude of 700 V can significantly increase the corrosion resistance of Cr−O−N coatings on steel substrates.

Improved pulse high frequency voltage injection method based low-speed sensorless control of axial field flux-switching permanent magnet motors

Improved pulse high frequency voltage injection method based low-speed sensorless control of axial field flux-switching permanent magnet motors

Control strategy of the novel stator free speed regulating wind turbine generation system.

Building a high-proportion renewable energy power system is a key measure to address the challenges of the energy revolution and climate change. However, current high-proportion renewable energy systems face issues of frequency instability and voltage fluctuations. To address these challenges, this paper proposes a novel topology for a stator free speed regulating wind turbine generation system. The stator free speed regulating machine connects a gearbox and a synchronous generator, forming a flexible drive chain that increases system inertia and enhances frequency stability in high-proportion renewable energy power systems. The synchronous generator at the end of the drive chain can be directly connected to the grid without the converter, thanks to the speed regulation provided by the stator free speed regulating machine, thus avoiding harmonic pollution caused by power electronic devices in traditional wind turbines, enhancing the reactive power support capability, and improving voltage stability in high-proportion renewable energy systems. Given that the proposed stator free speed regulating machine consists solely of a rotating inner and outer rotor without a stator, traditional motor control strategies are not applicable. Therefore, this paper focuses on developing control strategies for the stator free speed regulating machine, employing a dual closed-loop PI control strategy with an outer loop for speed and an inner loop for current, based on flux orientation of the outer rotor. Simulation experiments will validate the feasibility of the proposed stator free speed regulating wind turbine generation system topology and the effectiveness of the control strategy.

A gallium oxide MESFET transistor with potential barrier layers for high-power and high-frequency applications

Abstract In this article, a novel gallium oxide metal semiconductor field effect transistor (MESFET) is presented. This device is designed for high-power and high-frequency usage and features embedded potential barrier layers on each side of the gate metal within the channel. The gallium oxide semiconductor (Ga2O3) is highly valued in semiconductor technologies because of its large band gap (4.9–4.8 eV) and high breakdown field (6–8 MV cm−1). These properties make it suitable for high-power and high-frequency operations. We call the proposed structure; the potential barrier layers in Gallium Oxide MESFET (PBL-GO-MESFET). The key idea in the PBL-GO-MESFET transistor is embedding the PB layers to control the electric field distribution. Because of the PB layers, an increased breakdown voltage is observed in the PBL-GO-MESFET device, which is in contrast to conventional GO-MESFET (C-GO-MESFET) devices. The simulation findings indicate that the PBL-GO-MESFET transistor surpasses the C-GO-MESFET transistor in terms of breakdown voltage and radio frequency (RF) traits.

Numerical Investigation of Piezoelectric Energy Harvesting From a Multi-Mode T-Shaped Structure

In this work, energy harvesting from a proposed three-mode T-shaped structure, composed of a vertical beam, two horizontal beams, a center mass, and tip masses, is investigated to expand the frequency bandwidth for energy harvesting, without compromising the power density due to the additional mass of the structure, as is the case with most multi-mode harvesters. The aim is to cleverly use and position the additional mass to help induce higher and more uniform strain levels throughout the piezoelectric patch, leading to greater power generation to help counteract the added mass. A numerical model was developed to analyze the structure, to obtain voltage and power frequency responses, taking into effect the load resistance modeling and the accurate evaluation of resonance peaks by estimating each mode damping ratio. The validity of the model was confirmed by comparisons with previous experiments involving other structures, which demonstrated strong agreement. The excitation load was strategically applied to induce maximum displacement of the center and tip masses relative to the fixed ends in each mode. The outcomes reveal that the T-shaped configuration exhibits the capacity to generate higher maximum strain and a more uniform strain distribution across the piezoelectric patch when compared to previous L-shaped and traditional cantilever harvesters' designs. These characteristics yielded a power density higher than that of the L-shaped structure by approximately 70% with only around 20% addition in structure mass. Additionally, the multi-mode T-shaped structure boasts a significantly broader harvesting bandwidth due to the additional mode, without compromising power density, as was the case with L-shaped structures. Furthermore, the positioning of the tip mass was systematically altered to assess its impact on the frequency bandwidth and power output of the horizontal and vertical beams in the three bending modes, demonstrating great robustness and tuning capabilities.

Grid-connected double-stage PV system with space vector PWM inverter and MPPT

Because of the increasing demand for non-conventional energy sources, photovoltaic system integration into the electrical grid is becoming more crucial. It is advised to employ a double-stage grid-connected PV system. This can be employed with the main parts boost converter, which helps to boost the DC output from the PV channels. And next one is the space vector pulse width modulation (SVPWM) inverter which can provide better harmonic performance and higher efficiency compared to traditional PWM methods. The SVPWM technique is employed to modulate the inverter output, generating a sinusoidal AC waveform that matches the grid frequency and voltage. By adjusting the pulse width to achieve effective and trustworthy grid integration. To maximize power extraction takes place by using maximum power point tracking (MPPT). The SVPWM inverter is crucial in converting DC power to AC power and enabling grid connection. Utilizing SVPWM allows exact control of voltage magnitude, frequency, and phase angle to provide high-quality sinusoidal AC output voltage. The power quality of the electricity pumped into the grid is improved by this precise management, which also ensures adherence to grid standards and reduces harmonic interference.

Investigation of Interface States, Series Resistance and Barrier Height Variation with Frequency in Al/WO3/p-Si (MOS) Capacitors

In the study, Tungsten oxide (WO3) was synthesized via the sol-gel method on P-type 〈100〉 silicon wafer. Electrical characterization of the Al/WO3/p-Si (MOS) capacitor was performed through capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements at different frequencies (from 50 kHz to 1 MHz). As the applied voltage frequency increased, the maximum values of the measured C-V and G/ω-V characteristics decreased. This phenomenon was attributed to interface state trap (Dit) charges following low-frequency AC voltage signals. The variation of series resistance (Rs) and barrier height (ΦB) with frequency was examined. It was shown that Rs significantly affects the device behaviour. The ΦB also decreased with increasing frequency. This situation is suggested to indirectly affect the mobility of charge carriers directly through the Vo value. Ultimately, although WO3 material exhibits variable results in terms of dielectric properties, the study's finding of a high dielectric constant (e.g., 3688.75) is consistent with similar results in the literature. This high dielectric property underscores the material's importance for future applications.

ЕЛЕКТРОМЕХАНІЧНІ ХАРАКТЕРИСТИКИ БЕЗКОНТАКТНОГО ДВИГУНА З ПОСТІЙНИМИ МАГНІТАМИ ПРИ ШИРОТНО-ІМПУЛЬСНОМУ ЖИВЛЕННІ

The paper is devoted to the study of the characteristics and operating modes of a brushless permanent magnet motor in the structure of an electric drive with a two-wire external power supply from a voltage source with pulse-width regulation. The dependences of the motor rotation frequency, the stator current effective value and the average value of the current in the DC link of the voltage inverter, as well as the dependences of the torque coefficient on the average value of the motor torque are given. The influence of the frequency of the pulse supply voltage on the operating modes of the motor is studied. The current and torque limitation modes of the motor in a system with a single-position relay controller and a fixed transistor shutdown interval former are studied. Ref. 12, fig. 16.

Online High Frequency Impedance Identification Method of Inverter-Fed Electrical Machines for Stator Health Monitoring

In electric powertrain traction applications, the adopted trend to improve the performance and efficiency of electromechanical power conversion systems is to increase supply voltages and inverter switching frequencies. As a result, electrical machine conductors are subjected to ever-increasing electrical stresses, leading to premature insulation degradation and eventual short-circuits. Winding condition monitoring is crucial to prevent such critical failures. Based on the scientific literature, several methods can be used for early identification of aging. A first solution is to monitor partial discharges. This method requires the use of a specific measurement device and an undisturbed test environment. A second solution is to monitor the inter-turn winding capacitance, which is directly related to the condition of the insulation and can cause a change in the stator impedance behavior. Several approaches can be used to estimate or characterize this impedance behavior. They must be performed on a machine at standstill, which limits their application. In this paper, a new characterization method is proposed to monitor the high-frequency stator impedance evolution of voltage source inverter-fed machines. This method can be applied at any time without removing the machine from its operating environment. The range and accuracy of the proposed frequency characterization depend in particular on the supply voltage level and the bandwidth of the measurement probes. The effects of parameters such as temperature, switching frequency, and DC voltage amplitude on the impedance characteristic were also studied and will be presented. Tests carried out on an automotive traction machine have shown that the first two series and parallel resonances of the high-frequency impedance can be accurately identified using the proposed technique. Therefore, by monitoring these resonances, it is possible to predict the aging rate of the conductor.

(Invited) AFM for Nanoscale Morphology & Property Characterization of Traditional and Emerging Semiconductors and Ferroelectrics

A wide range of characterization methods based upon Atomic Force Microscopy (AFM) can be applied for nanometer scale analysis of semiconductor and electronic materials & devices. The standard capability of AFM to image the surface topography with nanometer scale spatial resolution is augmented with the capability to measure a variety of physical properties: electrical (for example, surface potential, work function, conductivity, carrier density), magnetic, thermal (temperature distribution, thermal conductivity), and mechanical. More recently, this capability has also been expanded to chemical identification at the nanometer scale using AFM-IR imaging and spectroscopy.We will cover a structured overview of these operating modes presenting their capabilities and limitations with case studies in semiconductor, ferro-electrics and general nanoelectrical devices. The operating modes are compared in terms of (i) physical properties characterized (carriers, charges, conductivity, ferro-electricity, dielectric constant, ...), (ii) spatial resolution, (iii) sensitivity, (iv) dynamic range, and (v) quantification potential. The capabilities and limitations of each operating mode are illustrated with examples from Si-based devices as well as compound semiconductors (HEMT and other), organic devices, and 1D & 2D materials.Novel approaches and novel prob & cantilevers focus on improvements in spatial resolution, detection sensitivity and the capability to correlate multiple properties efficiently. One such approach consists of datacube modes where one acquires an electrical or chemical spectrum in every pixel of the image: one of the parameters controlling the electrical measurements (for example DC voltage, AC voltage or AC frequency) is varied between two user defined values in each pixel of the 2D image. When combined with force mapping method, one simultaneously obtains a correlated nano-mechanical data cube holding information on modulus, stiffness, and adhesion. At the same time, one avoids contact mode imaging, thus extending electrical measurements to soft and fragile samples and improving measurement consistency as compared to conventional contact mode operation. Optimization of the force mapping movements and the electrical measurement setup allows one to maintain a relatively high imaging speed (typ. 10-100 ms/pixel). The approach is illustrated by multiple modes: in conductive AFM, I-V spectra in each pixel are acquired by ramping the DC bias. Applied to SCM and sMIM, dC/dV-V and C-V spectra are acquired. In PFM either switching loops or contact resonance spectra are obtained. Investigation of a variety of materials illustrates the capability to reveal sample properties which are not accessible or easily missed in conventional methods where maps at only one or a few discrete settings are acquired. The datacube approach can also be combined with chemical characterization offered by the AFM-IR method, in this way, offering a path to correlated mechanical-chemical analysis.

Analysis of Lattice Damage in Annealed 4H-SiC Epiwafers after Heated Implantation with High Energy Al Ions

Silicon Carbide (SiC) is a semiconductor with a wide bandgap having substantial potential for power devices. Its characteristics, including wide bandgap, high breakdown voltage, and thermal stability, enable SiC devices to operate in severe conditions such as high temperature, voltage, and high frequency [1]. High voltage devices made of 4H-SiC, capable of withstanding 1.7 to 6.5 kV, are sought for in uses like hybrid systems, shipboard and power grid systems, and high-speed trains. These devices are typically produced on 4H-SiC wafers with thick epilayers to enhance breakdown voltages [2], but achieving uniform doping in such thick epilayers is challenging. One solution is to employ multi-step high energy ion implantation system established at Brookhaven National Laboratory’s Tandem Van de Graaff accelerator facility [3], which can conduct the implantation at energies up to 150 MeV. This system has been used to demonstrate medium voltage charge balance devices, 2 kV and 3.8 kV superjunction structure PIN diodes [4-6]. However, high energy ion implantation causes significant lattice strain by displacing host atoms in the epilayer, so it is crucial to characterize the strain to understand the damage induced by high energy implantation. Further the process of implantation and subsequent activation annealing must be optimized to completely heal lattice damage.Previously, the distribution of strain within the 12 µm epilayer of a 4H-SiC epiwafer, implanted with high energy Al ions at a dose of 5.56 x 1013 cm-2 at room temperature, was characterized using synchrotron X-ray plane wave topography (SXPWT) and reciprocal space mapping (RSM). The analysis revealed that the strain level in the implanted region was approximately 2.5 x 10-4 higher than in the unimplanted region [7], as depicted in Fig.1 (a). The intensity profile obtained from the topograph was fitted using Rocking Curve Analysis by Dynamical Simulation (RADS) (Fig. 1(b)), and corresponding strain profile within the epilayer (Fig.1 (c)) also indicate a maximum strain of about 2.4 x 10-4. To completely alleviate this strain, an annealing temperature as high as 2000 °C is required [8]. However, such elevated temperature results in the wafers having rough surfaces, which is undesirable for device fabrication. One strategy to reduce the annealing temperature involves conducting high energy implantation at elevated temperatures, as the dynamic annealing effect can partially reduce the lattice strain in the as-implanted wafer. 4H-SiC epiwafers implanted at room temperature (RT), 300 °C, and 600 °C with a dose of 5 x 1016 cm-3 were characterized by RSM, as illustrated in Fig. 1(d). The strain estimated from vertical peak separation was 4.1 x 10-4, 3.3 x 10-4, and 2.0 x 10-4 for wafers implanted at RT, 300°C, and 600°C, respectively. The reduction of strain with increasing implantation temperature indicates that the dynamic annealing process was successfully initiated. These wafers will undergo activation annealing at standard temperatures, and the lattice strain will be measured and analyzed. The effectiveness of high temperature implantation will be assessed through these studies and reported in this paper.Reference:[1] J. Guo, Y. Yang, B. Raghothamachar, T. Kim, M. Dudley, J. Kim, J. Cryst. Growth 480 119-125. (2017)[2] T. Liu, S. Hu, J. Wang, G. Guo, J. Luo, Y. Wang, J. Guo and Y. Huo, IEEE Access, 7 145118-145123. (2019)[3] P. Thieberger, C. Carlson, D. Steski, R. Ghandi, A. Bolotnikov, D. Lilienfeld, P. Losee, Nucl. Instrum. Methods Phys. Res. B: Beam Interact. Mater. At. 442 36-40. (2019)[4] R. Ghandi, C. Hitchcock, S. Kennerly, ECS Transactions 104 67 (2021)[5] R. Ghandi, A. Bolotnikov, S. Kennerly, C. Hitchcock, P.-m. Tang, T.P. Chow, 2020 32nd International Symposium on Power Semiconductor Devices and ICs (ISPSD), IEEE, 126-129 (2020)[6] R. Ghandi, C. Hitchcock, S. Kennerly, M. Torky and T. P. Chow, 2022 International Electron Devices Meeting (IEDM), pp. 9.1.1-9.1.4 (San Francisco, CA, USA, 2022)[7] Z. Chen, H. Peng, Y. Liu, Q. Cheng, S. Hu, B. Raghothamachar, M. Dudley, R. Ghandi, S. Kennerly and P. Thieberger, Materials Science Forum 1062, 361-365 (2022)[8] Z. Chen, Y. Liu, H. Peng, Q. Cheng, S. Hu, B. Raghothamachar, M. Dudley, R. Ghandi, S. Kennerly and P. Thieberger, ECS J. Solid State Sci. Technol. 11 065003 (2022) Figure 1

(Invited) Thin Film Technologies : The Key Approach for the Decrease of Energy Consumption of the Digital World

Since the early 2000s, thanks to the parallel development of microelectronic tools and equipment, the increased possibility of nomadizing objects and improved transmission techniques, digital technologies have gradually invaded our 21st century world. The Internet of Things (IoT) and the Internet of Everything (IoE), based on connected objects, apply just as much to industry, online purchasing, leisure, finance and administration. All sectors of society are impacted, from communications, transport and energy, to health, the environment, security and industrial production (Industry 4.0).This field has experienced exponential growth since 2005, accelerating with the arrival of new application sectors such as social networks that concern the global population, cloud storage, crypto-currencies, 5G-6G, and especially artificial intelligence (AI) in recent years. All these new applicative domains are physically based on hardware that is constitued of electronic components and systems realized with microelectronic or even nanoelectronic elementary devices, integrated components and circuits, and large-area components including all display, signal sensor, actuators, and energy conversion devices. All this equipment needs to be supplied with electrical power in order to operate in a system that is essentially remote from the individual user.Thus, transparency on the user side of this digital world overshadows the fact that the associated energy consumption is also growing exponentially, despite improvements in microelectronics products that are therefore not yet sufficient. As exponential variation is not physically acceptable in the long term, we could in fact find ourselves in a global energy impasse over the next decade, as the electrical power required for digital technology becomes greater than the electrical power currently produced worldwide. Today's challenge is to reduce the energy consumption of all electronic systems, whether analog or digital, high-power, high-frequency and highly integrated. This approach must combine very large-scale integration and thin-film technologies, with new thin-film transistor architecture and/or devices based on new materials. After summarizing the context of the digital world and its challenges, this presentation examines the various proposals for improving electronics, both technologically and architecturally, involving transistors, devices and thin-film circuits. Indeed, new three-dimensional approaches combine highly integrated circuit techniques with thin-film technologies based on successive stacking of component layers. This technological architecture makes it possible to reduce the length of interconnection tracks, thereby improving signal transfer times and reducing resistive losses.The introduction of new materials such as metal oxide semiconductors, indium gallium zinc oxide (IGZO), or wide-bandgap semiconductors such as gallium nitride (GaN) or silicon carbide (SiC), can significantly reduce leakage currents in electronic components. These materials can be used in new semiconductor-on-insulator processes, extending the silicon-on-insulator approach. Indeed, the smart-cut technique applied to these wide-bandgap semiconductors can significantly reduce transistor leakage current and improve electrical characteristics such as breakdown voltage, on-resistance and cut-off frequency. This technique also allows reducing the power consumption of optolectronics devices. In addition, the use of a high permittivity insulator significantly decrease the off-state power consumption of each transistor, resulting in an energy efficiency improvement factor of up to ten.The recent development of integrated architectures based on flexible materials for large-area electronics paves the way for relatively low-power electronics. Indeed, a thin layer of indium gallium zinc oxide (IGZO) has been deposited on a flexible substrate, enabling the creation of a first-generation microprocessor (Intel 4004). In this circuit, IGZO-based transistors have a very high Ion/Ioff ratio which significantly minimizes leakage current and therefore power consumption. When the frequency performances do not limit the application, this type of circuit can be easily introduced in connected objects. Efforts on technological processes and new thin-film materials are complemented by new circuit and electrical system architectures. They should lead to an evolution of circuit architecture from a synchronous approach to an asynchronous and analog approach, which fortunately allows better control of energy consumption. For example, the introduction of a deep standby mode, generally used in case of inactivity, can considerably reduce losses and power dissipation.All these improvements can only be effective if future employees in the sector are capable of innovating. This challenge complements those of a technical nature. Indeed, globally, the electronics sector is experiencing a growing skills shortage, with many jobs going unfilled. There is an urgent need to train new engineers, technicians and doctors to increase the pool of specialists in the field, with training based on the knowledge and know-how of thin film technologies. The last part of the presentation is devoted to this issue and to the actions carried out by the French national network of higher education in microelectronics as part of a national France 2030 program.

Concept and Advantages of Carbon/Air Secondary Battery System as a Fixed Compact Power Storage with Large Capacity

Introduction One of the critical technological isuues to constract carbon neutral society is the suppression of the impact of the volatility in power generation from inexpensive variable renewable energy power sources, such as solar cells and wind powers. It is necessary to maintain a balance between power generation, transmission, and consumption, and to maintain three types of stability in the power system: frequency stability, synchronization stability, and voltage stability. For this reason, energy storage technology is one of the most important issues for making up carbon neutral energy system. Among energy storage technologies, lithium-ion secondary batteries are superior in terms of both output density and energy density, but they present a cost challenge for large-capacity energy storage. Pumped storage power generation is the mainstay of long-term large-capacity energy storage in the current power system, but significant pumped storage expansion is subject to geopolitical constraints. Therefore, a compact, large-capacity energy storage system that can be installed in the power grid is required to expand the introduction of variable renewable energy power sources.In this research, we first describe the operating mechanism and advantages of the "Carbon/Air Secondary Battery (CASB) system" [1,2], a compact power storage system that integrates the functions of a solid oxide fuel cell that generates electricity by producing CO2 through the oxidation reaction of carbon and a solid oxide electrolytic cell that produces carbon through the electrolysis of CO2. The operating mechanism and features of the CASB system are introduced. In addition, we report the calculation results of feasible system efficiency based on thermodynamic considerations compared to power storage system using H2/H2O-solid oxide fuel cells/electrolysis cells. In addition, the advantages/disadvantages of the two types of CASBs, integrated type of CASB between carbon deposition /electrochemical reaction, and the separated type of CASBs, as well as their representative charge/discharge characteristics will be presented. Theoreticl advantage of CASB as a fixed compact power storage with large capacity The theoretical charge/discharge efficiency of CASB, which is the ΔG/ΔH of reaction “C+O2→CO2” is 100%. This means that there is no heat input and output ideally in both carbon generation and CO2 electrolysis (in charge/discharge). Therefore, temperature control is simple and a heat exchanger can be minimized, which may allow the system to be compact. The feasible charge/discharge system efficiency of CASB including possible heat exchange were estimated as 92% based on thermodynamics, which is much higher than that of power storage system using H2/H2O-solid oxide fuel cells/electrolysis cells (63%). In addition, since CO2 can be liquefied at about 6.4 MPa at 25°C, its volumetric energy density to 1.62 × 103 Wh L-1, about four times higher than the volumetric energy density of hydrogen compressed at 20 MPa at 25°C, 3.79 × 102 Wh L-1. A key technological point of CASB at its discharging , which is combination between electrochemical reaction (CO2→ CO+O2-) and thermochemical reaction (2CO→ C+CO2) by achiving at closed system The discharge reaction of the CASB is the same as that of the Rechargeable Direct Carbon Fuel Cell [3,4,5]. The reason for the first successful demonstration of the CASB is that the combining electrochemical reaction with low overpotential (CO2 →CO+O2-) with the thermochemical reaction, the Boudouard equilibrium reaction (2CO → C+CO2) were achieved at the charging by making the system a closed system. Two types of CASBs, (1) Integrated type of CASB between carbon deposition /electrochemical reaction, and (2) the separated type of CASBs Since generally, the carbon deposition on the electrode cause its degradation [6], two type of CASBs can be designed and demonstrated (as shown in Fig.1). Both types of CASBs could be demonstrated.

A bidirectional DC/DC converter for renewable energy source-fed EV charging stations with enhanced DC link voltage and ripple frequency management

The amount of electricity that the grid must supply has increased as the number of electric vehicles (EVs) has increased. The best way to minimize power pollution between the automobile and the grid is to use an EV charging station to establish a bidirectional connection with an energy storage unit (ESU). This paper proposes a bidirectional DC/DC converter for battery available at the renewable energy sources (RES) fed charging station. This bidirectional DC-DC converter has important advantages such as dc link voltage stress reduction and the ripple frequency of inductor current is two times of the converter's switching frequency. The proposed converter consists of two identical Zero Voltage Transition (ZVT) cells and each cell includes a capacitor, two resonant inductors and a supplementary switch which is combined with the traditional three level topology that enables both buck and boost operating modes. The simulation-based analysis has been done using MATLAB/Simulink. The simulation results have been verified with the help of experimental setup is presented for the converter module for validating the charging station.