Modern Power Electronic Systems Research Articles

Influence of surface chemical modifications on enhancing the aging behavior of capacitor biaxially-oriented polypropylene thin film

Modern power electronic systems require appropriate metallized polypropylene capacitors (MPCs) to operate in harsh environments. Due to their limited operating capabilities, commercial biaxially-oriented polypropylene (BOPP) films—the primary component of MPCs—are susceptible to degradation in high electric fields and at high temperatures. In order to enhance the aging behavior of BOPP, this work proposes one-sided phosphorylation at optimum and excessive acid concentrations of 8 % and 15 % for 24 hours at a [high] temperature of 60 °C. The proposed surface modifications' success in enhancing the aging behaviors of BOPP is confirmed by DC electrothermal aging. Field emission scanning electron microscopy (FE-SEM) analysis reveals changes in surface morphology resulting from phosphorylation. The changes in crystal structure of the original and phosphorylated samples are evaluated using X-ray diffraction (XRD). The average crystallite size, dislocation density, and microstrain during aging are also characterized using the Williamson-Hall (W-H) analysis method. Fourier transform infrared (FTIR) spectroscopy is used to identify changes in the chemical composition and functional groups resulting from phosphorylation and aging, while X-ray photoelectron spectroscopy (XPS) is used to analyze changes in the surface chemical elements of the original, phosphorylated, and aged samples. The charge-thermally stimulated discharge (C-TSD) technique and broadband dielectric spectroscopy (BDS) are used to verify the electrical performance. Mechanical properties, including thermal stability, are measured using the dynamic mechanical analysis (DMA) technique. The results indicated that the optimized phosphorylation improved the BOPP film's electrical and mechanical properties. As a result, the surface charge stability was found to increase under thermally stimulated discharge by 74 % and the dielectric constant by 2 %, while the dielectric losses decreased by 20.2 %. Under aging, for the first time, the dielectric constant was found to increase by 4.8 %, while dielectric losses decreased by 8.9 %. In return, deformation resistance, ductility, and lower energy dissipation demonstrated enhanced mechanical performance.

Analytical Selection of Leakage Inductance for Single-Phase Dual Active Bridge Converters

The single-phase dual active bridge (DAB) DC/DC converter is a vital component in modern power electronics systems, facilitating efficient bidirectional power transfer between various energy sources and loads. One of the critical aspects in the design of such converters is the selection of an appropriate leakage inductance, as it significantly affects the circulating power within the converter. This study investigates the influence of inductance on the reactive power flow and introduces an analytical formula for calculating the necessary leakage inductance based on the specified rated power of the DAB converter. By employing the inductance values determined through the proposed formula, the developed power control-based modulation method, implemented in discrete time, successfully achieves zero reactive power caused by the first harmonic components under all load conditions. This selection of leakage inductance optimizes the performance of the converter ensuring efficient power delivery across various applications. The applicability of this method extends to various DAB applications, including electric vehicles, integration with asynchronous microgrids, and aerospace systems.

An improved modulation technique suitable for a three level flying capacitor multilevel inverter

This research paper introduces an innovative modulation technique for controlling a 3-level flying capacitor multilevel inverter (FCMLI), aiming to streamline the modulation process in contrast to conventional methods. The proposed simplified modulation technique paves the way for more straightforward and efficient control of multilevel inverters, enabling their widespread adoption and integration into modern power electronic systems. Through the amalgamation of sinusoidal pulse width modulation (SPWM) with a high-frequency square wave pulse, this controlling technique attains energy equilibrium across the coupling capacitor. The modulation scheme incorporates a simplified switching pattern and a decreased count of voltage references, thereby simplifying the control algorithm.

Power electronics anomaly detection and diagnosis with machine learning and deep learning methods: A survey

Power electronics pertains to the conception, regulation, and utilization of electronic power circuits to proficiently administer and transform electrical energy. Power electronics play a crucial role in maintaining the reliability, efficiency, and security of complex production systems. Also, increasingly important in various applications such as renewable energy systems, electric vehicles, and industrial automation. However, modern power electronics systems are vulnerable to both cyber and physical anomalies due to the integration of information and communication technologies. So far, different methods have been used to detect abnormalities. This survey provides an overview of the state-of-the-art in anomaly detection in power electronics using machine learning and deep learning methods. It highlights the potential of these techniques in addressing the growing complexity and vulnerability of power electronics systems.

Design of Boost Integrated Luo Converter for Grid Tied EV Based Charging Station

The combination of Renewable Energy Source (RES) and storage element in charging station is a possible solution for meeting the growing energy requirement of electric vehicles (EVs). In a grid-tied RE system, the converters are essential for attaining the process of power conditioning. Conventional DC-DC converters suffer from issues like voltage spikes, electromagnetic interference, and efficiency losses. The necessity for integrated converters arises from the demand for improved power conditioning, increased power density, and enhanced overall system performance. As a result, in this work, boost integrated Luo converter is proposed due to the ability to address aforesaid drawbacks and offer superior power conditioning capabilities in modern power electronic systems. The Luo converter with conventional boost converter aids in alleviating the current ripples to a greater extent. The PI control with Particle Swarm Optimization (PSO) strategy is efficiently employed in this study as provides consistent voltage supply to the converter. Thus, the ultimate aim of this work is achieved by enhancing the low dc voltage of PV panel by using a PSO-PI control-based hybrid converter, which increases its efficiency, lowers the cost, supplies suitable current and voltage for energizing the battery or to charge the grid tied EV charging station. The simulation results obtained verifies the effectiveness of developed system.

Analysis on Iron Loss of Sendust Dust Cores Based on Magnetization Reversal Processes

Iron loss of soft magnetic materials has been a major part of energy loss in modern power-electronics systems. Iron loss has been usually analyzed phenomenologically, but its physical mechanism has not been well understood yet. In this study, the iron loss of Sendust dust cores were investigated by means of models based on magnetization reversal processes. Broad-band iron loss and permeability measurements were performed by combining conventional two-coil and capacitive cancellation methods. As a result, irreversible and reversible magnetization processes are dominant for the lower and higher frequency regions, respectively, and the large increment of iron loss for the frequency higher than 1 MHz is attributed to the change in the magnetization reversal mode. Furthermore, this change in the magnetization reversal mode is well consistent with the change in the effective domain wall number with the frequency.

Confluence of Integrated Magnetics and TCM for a ZVS Based Higher Order Differential-Mode Rectifier

Two driving performance metrics in modern power-electronic systems are power density and efficiency: usually, improvement in one result in sacrificing the other. In this paper, triangular conduction mode (TCM) is used alongside integrated magnetics to achieve both performance metrics simultaneously. TCM is implemented by extending the switch current high enough to reverse direction and provide enough energy at the onset of the deadtime to discharge the parasitic capacitance of the SiC MOSFET. The elevated current ripple is alleviated by distributing the rectifier low-frequency current among parallel interleaved sub-modules. Taking advantage of the symmetrical topology of the differential mode Ćuk rectifier (DMCR), an integrated interleaved magnetic (IIM) structure is proposed to house all the inductors in a module. In doing so flux cancellation technique is used between the Ac-and Dc-side inductors to reduce the losses and size while using a custom core structure to control the flux coupling between the interleaved windings. A step by step design algorithm is presented to manage the different types of coupling within IIM. Challenges in design, fabrication, and testing of the system are analyzed and appropriate solutions are presented in each section. The solutions are supported by mathematical analysis to optimize the power stage design and validated by circuit as well as finite element simulations. An experimental setup is assembled to test this concept and multiple time-domain and parametric results are presented for proof of the concept in rectifier mode and single module mode.

An Overview of Lifetime Management of Power Electronic Converters

An expected lifetime of converters is of great importance for optimal decision-making in the planning of modern Power Electronic (PE) systems. Hence, the lifetime management of power electronic systems has attracted a lot of attention in academia and industry. This paper is a guideline for managing the lifetime of power converters. Analyzing the different kinds of failures, failure modes and their corresponding mechanisms are investigated in the first section along with the failure data needed as input parameters of the assessment. In the second section, lifetime prediction in two aspects of component-level and system level is discussed and all the possible techniques to achieve them are investigated and compared. All the steps required to predict the lifetime in the component-level including electrothermal modeling, cycle counting, lifetime model, damage accumulation, parameter estimation, and lifetime distribution are described and then system level methods consisting of reliability block diagrams, fault-tree analysis, and Markov chains are examined and compared. The last section contains the roadmap of the lifetime extension including the reliable design and condition monitoring.

A Facile In Situ Surface‐Functionalization Approach to Scalable Laminated High‐Temperature Polymer Dielectrics with Ultrahigh Capacitive Performance

AbstractHigh‐temperature dielectric materials for capacitive energy storage are in urgent demand for modern power electronic and electrical systems. However, the drastically degraded energy storage capabilities owing to the inevitable conduction loss severely limit the utility of dielectric polymers at elevated temperatures. Herein, a new approach based on the in situ preparation of oxides onto polyimide (PI) films to high‐temperature laminated polymer dielectrics is described. As confirmed by computational simulations, the charge injection at the electrode/dielectric interface and electrical conduction in dielectric films are substantially depressed via engineering the in situ prepared oxide layer in the laminated composites. Consequently, ultrahigh dielectric energy densities and high efficiencies are simultaneously achieved at elevated temperatures. Especially, an excellent energy density of 1.59 J cm−3 at a charge–discharge efficiency of above 90% has been achieved at 200 °C, outperforming the current dielectric polymers and composites. Together with its excellent discharging capability and cyclic reliability, the laminate‐structured film is demonstrated to be a promising class of polymer dielectrics for high‐power energy storage capacitors operating at elevated temperatures. The facile preparation method reported herein is readily adaptable to a variety of polymer thin films for energy applications under extreme environments.

Design, Implementation, and Validation of Electro-Thermal Simulation for SiC MOSFETs in Power Electronic Systems

Silicon carbide (SiC) mosfets are getting popular in high-frequency power electronic (PE) applications. More and more concerns for system efficiency and reliability are growing due to the increasing switching losses and thermal stress. In this article, an electro-thermal simulation method for SiC mosfets in modern PE systems is proposed. In the device simulation, a behavioral transient model of SiC mosfets is developed and used for generating a multidimensional power loss table in a wide range of operating conditions. The effects of parasitic elements, temperature-dependent parameters, and reverse recovery effect of the diode are taken into account. Furthermore, the power loss look-up table is integrated into the PE system simulation with an additional Cauer-based dynamic thermal model considering heatsink impact. In this way, the instantaneous power losses and junction temperature can be obtained, respectively, with fast simulation speed, reasonable accuracy, and improved simulation convergence. The proposed approach is implemented in PSCAD/EMTDC and further validated by the experimental results of a double pulse test setup and a power factor correction system.

Effect of charge coupling on breakdown voltage of high voltage trench-gate-type super barrier rectifier

With the rapidly increasing demands pertaining to high voltage applications in modern power electronic systems, power devices have become widely used in today’s power applications. As a major carrier device without unreliable metal-semiconductor Schottky contact, super barrier rectifier (SBR) has been one of promising substitutions for traditional diodes since it was first introduced, owing to its excellent performance and reliability. The main principle behind SBR approach is to create an adjustable potential barrier in the MOS channel. The height of this barrier can be easily adjusted by the doping concentration in the channel and by the oxide thickness. Trench-gate-type SBR (TSBR) with a trench gate is so designed that the junction-type field-effect transistor effect of planar gate structure enables TSBR to be eliminated to have ultralow forward voltages and a good tradeoff between the forward voltages and reverse leakage currents. However, the charge coupling effect under reverse bias, which is usually neglected and not intensively studied, plays an important role in determining the breakdown voltage of TSBR for high voltage applications (above 200 V). In this paper, the two-dimensional electric field distribution influenced by the charge coupling effect is explained and verified by the analytical model and device simulations with TCAD software Sentaurus. Adjusting the key parameters including the trench depth, oxide thickness and mesa width can improve the tradeoff between the forward voltage drops and breakdown voltages. The optimization of key parameters can provide the significant guidance for designing the device structure. Furthermore, some considerations for designing the TSBRs are discussed in this paper. In addition, a novel TSBR with the stepped oxide structure (SO-TSBR) is proposed and demonstrated. Similar to, yet different from, the stepped oxide structure for dual trench MOSFET, the stepped oxide design equipped with this new rectifier possesses the ability to enhance the forward conduction. As indicated by the simulation results, the SO-TSBR reduces the forward voltage drop by 51.49% at a forward current density of 2.5 A/cm<sup>2</sup> compared with the normal structure of TSBR, with almost the same breakdown voltage of 270 V. The optimized TSBRs and SO-TSBRs are very promising rectifiers that can be used in high power electronic systems, because their breakdown voltages are both greater than 250 V.

Power Electronics in Renewable Energy Systems and Smart Grid: Technology and Applications [Book Review

This eighth book in the series of popular power electronics books authored/edited by Prof. Bimal K. Bose was released in June 2019 in the IEEE Press Series on Power Engineering. According to the author/editor, the idea for the book appeared after the publication of the special issue of Proceedings of the IEEE “Power Electronics in Smart Grid and Renewable Energy Systems” in November 2017. Prof. Bose managed to mobilize 19 outstanding specialists in the field of power electronics and energy systems from around the world, who presented current issues in the 12 chapters of the book. The authors of individual chapters systematically review the latest technologies and provide examples of applications to familiarize readers with problems and solutions of modern power electronics in renewable energy systems and intelligent networks. The excellent style of Prof. Bose is apparent as each chapter begins with a clear introduction and ends with a constructive conclusion. Moreover, each chapter contains an extensive list of publications and what should be emphasized—among them, the most up-to-date positions. Also, a list of abbreviations, biographies of contributors, and an index are included. This book is a valuable tool for graduate researchers, practicing engineers, and scientists working in the areas of renewable and distributed energy systems. It provides the needed technical background for each subject. Therefore, it is also suitable for senior undergraduate- and master’s-level students of electrical engineering and power system faculties interested in modern power electronic energy systems.

The use of acoustic emission elastic waves as diagnosis method for insulated-gate bipolar transistor

The article describes research into the use of acoustic emission elastic waves (AE) for diagnosing insulated-gated bipolar transistors (IGBTs). Currently used in many modern shipboard power electronic systems, IGBTs are crucial components required to operate with extreme reliability. The acoustic emission elastic waves method was used to determine the acoustic signals of switching transistor and can be used to monitor early stages of damage. Transistor diagnostics makes use of selected frequency descriptors of AE and appropriate signal analysis.

Comparison and Discussion on Shortcircuit Protections for Silicon-Carbide MOSFET Modules: Desaturation Versus Rogowski Switch-Current Sensor

Survivability of silicon-carbide (SiC) mosfet modules during short circuit (SC) is essential for modern power electronics systems due to large economic implications. SiC mosfet modules exhibit narrow SC withstand times and generally much lower SC robustness than silicon (Si) insulated-gate bipolar transistors (IGBTs). This puts a critical concern on their utilization, further stressing the importance of reliable protection. This article presents a comprehensive analysis and discussion on the SiC mosfet module SC protection and performance comparison between conventional desaturation detection, previously used for Si IGBT protection, and Rogowski switch-current sensor (RSCS) detection. In addition, this article presents the experimental design for soft turn-off as a reaction to the SC detection to avoid excessive overshoots during the abrupt turn-off of the SC current. To perform different types of SC with various fault inductances on different temperatures, and for the sake of fair comparison under the same conditions, a gate-driver unit for 1.2 kV SiC mosfet half-bridge modules is developed containing both detection methods. The results demonstrate that both methods are successful in protecting the module in all SC types, with superiority of the RSCS detection and concerns for desaturation detection in high-inductance and high dc-bus voltage SC events.

RETRACTED: Application of Machine Learning and Big Data in Doubly Fed Induction Generator based Stability Analysis of Multi Machine System using Substantial Transformative Optimization Algorithm

With the increase in the amount of data captured during the manufacturing process, surveillance systems are the most important decision making decisions. Current technologies such as Internet of Things (IoT) can be considered a solution to provide efficient monitoring of productivity. In this study, it has suggested a real-time monitoring system that uses an IoT, big data processing and an Offshore Wind Farm (OWF) model is proposed. The Offshore Wind Farm (OWF) is an extended level invasion in modern power electronics systems, in this proposed work Doubly Fed Induction Generator (DFIG) based multi machined OWF was designed, and power stability was analyzed using Substantial Transformative Optimization Algorithm (STOA). The Voltage Source Converter (VSC) and High Voltage Direct Current (HVDC) system was combined with onshore network. The terminal voltage of onshore network was controlled through Onshore Side Converter (OSC), active and reactive power was regulated separately using VSC. The performance of the onshore network was evaluated under renewable network errors (Total Harmonics distortion and steady state error) beside with OWF. The OWF - DFIG active and reactive power was controlled smoothly with in the limit of HVDC, and the power framework security can be updated by controlling the active power of the OSC to help its terminal voltage using STOA methodology. From the voltage control mode, the electrical faults are recovered rapidly with minimum fluctuation. The dynamic simulation comes about additionally demonstrate that onshore network fault can't impact OWF behind HVDC transmission system. Because of the specialized favorable circumstance, VSC-HVDC innovation, the constancy in OWF is very much ensured against the onshore grid faults. The proposed STOA based system has validated through simulation in Matlab Simulink environment. General, 97% effectiveness, accomplished at full load condition in light of the proposed system. The results showed that the IoT system and the proposed large data processing system were sufficiently competent to monitor the manufacturing process.

Data centers as a source of dynamic flexibility in smart girds

Data centers have a significant potential to become a major source of flexibility in smart girds. They consume currently roughly 3% of all the electricity produced globally and are expected to only increase their consumption as the world becomes more connected and digitalized.As data centers are required to operate without any interruptions, they use power protection systems and energy storages. This paper investigates the technical and economic feasibility of dual-purposing these power protection systems, the uninterruptible power supplies, and their batteries in data centers to perform primary frequency regulation services. While the topic of data centers and demand response has been extensively covered in the current scientific literature, the focus has been on the demand response enabled by server workload shifting or hardware-enabled peak shaving. Based on an extensive literature review, there is a knowledge gap in the literature concerning primary frequency regulation and dynamic response enabled by modern power electronics systems in data centers. In this paper, this knowledge gap is bridged by suggesting a novel approach of taking advantage of the bidirectional operations capabilities of the uninterruptible power supply systems, thereby enabling them to provide dynamic power response from their battery systems.The feasibility of this approach is examined with the proposed method, which includes (1) an analysis of the required energy for primary regulation and the availability of this energy in a typical data center, (2) a simulation of activation events and their impact on the service life of the battery systems, (3) reaction speed and reliability considerations of the operations, and (4) an economic feasibility and balancing market analysis.The results show that as primary frequency regulation is an energy nonintensive service and data center battery systems are by design oversized for redundancy reasons, typical data centers have more than ample amounts of energy to participate in the primary regulation without jeopardizing their own processes. The results also show that by maintaining reasonable levels of usage, the battery systems can be operated within their specifications, and the demand response operations will not cause premature aging of the battery systems. The reaction speed of the power electronics is found to be very high and easily meet the current market requirements.While the achievable revenue from the primary regulation service is small compared for example with the electricity costs of the data centers, it is still significant as there is little to no impact on the daily business of the data centers.

Renewable Energy Devices and Systems with Simulations in MATLAB and ANSYS [Book News

This book covers a wide range of problems related to renewable energy in depth. These stem from the currently observed transition from conventional generation, transmission, distribution, and utilization of energy based on fossil fuels to the emerging distributed generation system based on renewable energy sources. Note that recently, in terms of newly installed capacity, renewable generation is higher than conventional, and this tendency is growing. These changes are accompanied by efforts to increase the control and efficiency of energy use, which can effectively be done by using modern power electronic systems. The book is coauthored by 29 excellent specialists and consists of 14 chapters that cover such topics as: renewable energy systems, solar power generation, photovoltaic systems; power electronics; microgrids; and wind power generation. It should be stressed that despite the overlapping authorship of many chapters, no repetition can be found in the book, and the presented material is well balanced. The volume can be strongly recommended for a wide audience of both undergraduate and graduate students, engineering educators, and practicing engineers in the industry who are interested in the subject of modern renewable energy systems.

Enhanced dielectric properties and energy storage density of surface engineered BCZT/PVDF-HFP nanodielectrics

Polymer nanocomposites have proved to be promising energy storage devices for modern power electronic systems. In this work we have studied the dielectric properties and dielectric energy storage densities of 0–3 type BCZT/PVDF-HFP polymer nanocomposites with different filler volume concentrations. BCZT nanopowder was synthesized by solgel method through citrate precursor method. The structural and morphological features of the BCZT nanopowder were examined by X-ray diffraction and transmission electron microscopy. For better polymer ceramic interface coupling, BCZT was surface functionalized with extended aromatic ligand, naphthyl phosphate (NPh). The surface functionalization was validated and quantified by thermogravimetric analysis and X-ray photoelectron spectroscopy. The dielectric constant of surface passivated BCZT nanoparticles was estimated to be ~ 155 using slurry technique, while the dielectric permittivity of pristine BCZT nanopowder could not be assessed due to high innate surface conductivity. BCZT/PVDF-HFP polymer nanocomposite thin films were fabricated using solution casting technique. The dispersion quality of the ceramic fillers in the polymer matrix was examined by scanning electron microscopy. Due to better polymer ceramic interface, At 5 vol% filler concentration, NPh modified nanoBCZT/PVDF-HFP films showed enhanced dielectric breakdown strength and energy storage density than untreated nanoBCZT/PVDF-HFP and even pure polymer films. Maximum energy storage density of 8.5 J cm−3 was obtained at an optimum filler concentration of 10 vol% for surface functionalized BCZT/PVDF-HFP composite films of 10 μm thickness.

Harmonic Emissions of Three-Phase Diode Rectifiers in Distribution Networks

Harmonic emissions have been changed in distribution networks, with respect to frequency range and magnitude, due to the penetration of modern power electronics systems. Two new frequency ranges 2–9 and 9–150 kHz have been identified as new disturbing frequency ranges affecting distribution networks. This paper presents the effects of grid-connected three-phase systems with different front-end topologies: conventional, small dc-link capacitor, and electronic inductor. A power converter with a small dc-link capacitor can create a resonant frequency with the line impedance below and above 1 kHz depending on the grid configurations. The resonant effects depend on many factors, such as load power levels, filter types, and the number of parallel drives. These issues can affect the grid current harmonics and power quality of the distribution networks. Analyses and simulations have been carried out for three different topologies and the results have been verified by experimental test at system level. Current harmonic emissions have been considered for 0–2, 2–9, and 9–150 kHz frequency ranges.

Magnetic ageing study of high and medium permeability nanocrystalline FeSiCuNbB alloys

increasing the energy efficiency is one of the most important issues in modern power electronic systems. In aircraft applications, the energy efficiency must be associated with a maximum reduction of mass and volume, so a high components compactness. A consequence from this compactness is the increase of operating temperature. Thus, the magnetic materials used in these applications, have to work at high temperature. It raises the question of the thermal ageing problem. The reliability of these components operating at this condition becomes a real problem which deserves serious interest. Our work takes part in this context by studying the magnetic material thermal ageing. The nanocrystalline materials are getting more and more used in power electronic applications. Main advantages of nanocrystalline materials compared to ferrite are: high saturation flux density of almost 1.25T and low dynamic losses for low and medium frequencies. The nanocrystalline Fe73.5Cu1Nb3Si15.5B7 alloys have been chosen in our aging study. This study is based on monitoring the magnetic characteristics for several continuous thermal ageing (100, 150, 200 and 240°C). An important experimental work of magnetic characterization is being done following a specific monitoring protocol. Elsewhere, X-Ray Diffraction and magnetostriction measurements were carried out to support the study of the anisotropy energies evolution with ageing. This latter is discussed in this paper to explain and give hypothesis about the ageing phenomena.