Application Of Power Electronic Devices Research Articles

Reliable operation of Cr2O3:Mg/β-Ga2O3 p–n heterojunction diodes at 600 °C

Beta gallium oxide (β-Ga2O3)-based semiconductor heterojunctions have recently demonstrated improved performance at high voltages and elevated temperatures and are, thus, promising for applications in power electronic devices and harsh environment sensors. However, the long-term reliability of these ultra-wideband gap (UWBG) semiconductor devices remains barely addressed and may be strongly influenced by chemical reactions at the p–n heterojunction interface. Here, we experimentally demonstrate operation and evaluate the reliability of Cr2O3:Mg/β-Ga2O3 p–n heterojunction diodes during extended operation at 600 °C, as well as after 30 repeated cycles between 25 and 550 °C. The calculated pO2-temperature phase stability diagram of the Ga-Cr-O material system predicts that Ga2O3 and Cr2O3 should remain thermodynamically stable in contact with each other over a wide range of oxygen pressures and operating temperatures. The fabricated Cr2O3:Mg/β-Ga2O3 p–n heterojunction diodes show room-temperature on/off ratios >104 at ±5 V and a breakdown voltage (VBr) of −390 V. The leakage current increases with increasing temperature up to 600 °C, which is attributed to Poole–Frenkel emission with a trap barrier height of 0.19 eV. Over the course of a 140-h thermal soak at 600 °C, both the device turn-on voltage and on-state resistance increase from 1.08 V and 5.34 mΩ cm2 to 1.59 V and 7.1 mΩ cm2, respectively. This increase is attributed to the accumulation of Mg and MgO at the Cr2O3/Ga2O3 interface as observed from the time-of-flight secondary ion mass spectrometry analysis. These findings inform future design strategies of UWBG semiconductor devices for harsh environment operation and underscore the need for further reliability assessments for β-Ga2O3-based devices.

A new superior electronic properties Si allotrope for power electronic device applications

A new I−4 space group silicon allotrope is proposed in this paper. The electronics properties, mechanical properties and Ag(100)/I4Si(100) interface properties are studied using first principle calculations method. The results of the phonon show that I−4 Si is dynamically stable. Elastic constants reveal I−4 Si is dynamical stable. Electronics properties calculations reveal that the CBM and VBM of I−4 Si are at X and M point, which indicates that I−4 Si is an indirect band gap semiconductor with a high band gap of 1.95 eV. To satisfy the demands for fabricating electronic devices, the N-type doping, P-type doping and Ohmic contact are studied, too. The fermi energy level of N-type and P-type I−4 Si move into conduction band and valence band, respectively. The Schottky barrier of Ag/I-4 interface is 0.65 eV. Meanwhile, the current-voltage curve becomes highly symmetric, suggesting an Ohmic behavior of the Ag(100)/I4Si(100) interface. Critical breakdown field calculations results show that the critical breakdown field of I−4 Si is 9.05 × 105 V cm−1, which is 3.02 times that of the diamond Si. Because band gap and critical breakdown field of I-4 Si are much greater than that of diamond Si, I-4 Si is potential electronic semiconductor material. Thus, I−4 Si can be applied in the field of modern power electronic device applications due to its superior electronic properties.

Adaptive power capability control scheme for voltage source converter to improve transient stability

Applications of Power Electronic Devices (PED) are rapidly increasing because of their controllability. A Direct Current (DC) transmission system is used for the interconnection of Renewable Energy Sources (RES), and a DC grid research reached the stage of demonstration. Since power electronic devices are controllable, as opposed to conventional ac power facilities, various studies have been carried out on control schemes. Based on fast response speed, the device can affect the stability of the power system by improving the transient stability according to the control method. However, the operation range of converters is limited based on the normal state of the AC system. Therefore, the entire converter capacity cannot be used, and the same standard is applied even in the transient state. In this paper, a novel control scheme is proposed in order to improve the voltage and frequency stability by using the maximum capacity of the converter. The control scheme calculates an Adaptive Power Capability Index (APCI) based on the range of variation of frequency and voltage in the transient state, then applies this index to the controller. In order to verify the new control scheme, a dynamic model is developed and verified in a Transient Stability Analysis (TSA) program. Following the verification of the model, the model is applied to the actual power system data and the power system stability is analyzed.

Adaptive VSG control strategy considering energy storage SOC constraints

The virtual synchronous generator (VSG) control strategy is proposed to mitigate the low inertia problem in the power system brought about by the high percentage of distributed generation connected to the grid and the application of power electronic devices. In order to maximize the effectiveness of the advantages of the flexible and adjustable parameters of VSG control, an adaptive VSG control strategy considering SOC constraint of the energy storage unit is proposed in this paper. Considering the significant loss of service life by operating the energy storage unit at its limit state, based on the rate and degree of change in system frequency, the adaptive control strategy realizes the online adaptive adjustment of the inertia factor and damping factor under different perturbation conditions by adaptively adjusting the control parameters when the system frequency oscillates. Finally, the effects of this adaptive VSG control method and conventional VSG control method are compared by simulation in PLECS. Hardware-in-the-loop (HIL) experimental platforms and semi-physical simulation experiments are constructed on RTBOX, and the feasibility and validity of this adaptive VSG control strategy are verified.

Application of different MPPT algorithms for PMSG-based grid-connected wind energy conversion system

Renewable energy sources such as wind energy sources have become the most prominent area of research work over the last two decades. Extraction of maximum power and lowering of THD are still the main issues during the integration of wind energy sources to the grid due to the noncontrollable variability of wind energy sources and the application of power electronic devices as interfacing devices. The main objective of this paper is to utilize modern optimization techniques for extracting maximum power points and implementing a Multilevel inverter to obtain minimal THD. This paper has introduced Improved Grey Wolf Optimization with Levy Flight for tracking maximum power from WECS. This Levy flight concept is applied in combination with the improved hunting process of GWO for providing an efficacy solution and a high rate of convergence through global tracking. Distinct MPPT algorithms such as Perturb and Observe (P&O), Grey Wolf Optimization (GWO), and Levy Flight Grey Wolf optimization (LGWO) are presented, simulated, and analyzed using MATLAB/SIMULINK. These algorithms have been compared based on quantitative analysis to examine the stability, figure out performance, and verify the best algorithm among the proposed algorithms. The consequences of the comparison demonstrated the supercilious characteristic of LGWO in the matter of tracking GMPP, rate of convergence, and the time to catch GMPP. The multilevel inverter is utilized as an interfacing unit between wind energy sources and the grid. This power electronic-based multilevel inverter is the main source of harmonic generation. This harmonic has been reduced to 5.5% (THD) due to the application of a 23-level Cascaded H-bridge multilevel Inverter using MATLAB/SIMULINK software.

An Optimization of Least-Square Harmonic Phasor Estimators in Presence of Multi-Interference and Harmonic Frequency Variance

The wide application of power electronic devices brings an increasing amount of undesired harmonic and interharmonic tones, and accurate harmonic phasor estimation under a complex signal input is an important task for smart grid applications. In this paper, an optimization of least-square dynamic harmonic phasor estimators, considering multi-interference and harmonic frequency variance, is proposed. A comprehensive error index (CEI) composed of the fundamental-leakage-led harmonic amplitude estimation error, harmonic mutual interference, out-of-band interference, and harmonic frequency deviation is employed. The largest CEI part of least-square algorithms using three different signal decomposition models is analyzed for the first time, and variables to reduce this error component are then introduced using singular value decomposition. With the CEI and defined variables, a minimum-error estimation of harmonic phasors under various interference and harmonic frequency change is discussed. Numerical tests are performed, and the test results show that after the proposed optimization is applied to least-square algorithms, the harmonic phasor estimation errors are considerably reduced, especially for low-order harmonics. We also show the possibility of choosing desired optimal phasor filter design by balancing the measurement accuracy and data latency. For example, when the window length is set to three nominal cycles, the proposed optimization can yield both good accuracy and fast measurement speed for estimating harmonic phasors under multi-interference and harmonic frequency variance.

Quasi-vertical GaN merged PN Schottky diode by using the p-NiO/n-GaN heterojunction

In this study, a novel quasi-vertical GaN-on-sapphire MPS diode is fabricated by using the p-NiO/n-GaN heterojunction. The sputtered NiO covers the bottom and sidewall of trench region perfectly, presenting a hole concentration 2.2 × 1018 cm−3 and a mobility of 0.1 cm2/V•s. Compared with the Ni-anode SBD, the SBD and NiO/GaN heterojunction parts in the MPS diode turn on consecutively, resulting in a higher turn-on voltage of about 1.6 V (at the current of 1 A/cm2) and on-resistance of 3.5 mΩ·cm2. On the other hand, the depletion regions at the heterojunction interface suppress the electric field crowding and enhance the reverse breakdown voltage effectively. The TCAD simulation shows that the electric field modulation becomes weak slightly with the increasing p-NiO interval, resulting in the increasing electric field as well as the leakage current. Those results are beneficial to realize a high-performance GaN MPS diode for power electronic device applications.

Energy storage, electrocaloric and optical property studies in Ho-modified NBT – BT lead-free ferroelectric ceramics

A comprehensive investigation of structural, microstructural, optical, electrocaloric, and energy storage properties of Ho-modified NBT-BT lead-free ceramics was conducted from room temperature to a high-temperature region. Rietveld refinement confirms the coexistence of dual-phase monoclinic (Cc) and tetragonal (P4mm) phases in Ho-modified NBT-BT ceramics. A prominent monoclinic distortion was found with increasing Ho composition up to x=0.02, and then an abrupt decrease for x=0.03 ceramic was noticed. Of particular importance is the composition of x = 0.02, which exhibits a high electrocaloric temperature change (ΔT) of 0.73 K @ E = 20 kV/cm at a temperature of 373 K, and an optimal high recoverable energy storage density (Wrec) of 1.8846 J/cm3 along with an efficiency 83% was achieved. The frequency dependence ac-conductivity study promotes the reduction of oxygen vacancies at room temperature and the dominance of single ionized oxygen vacancies at very high temperatures well above 300 °C. A small considerable increase in the energy bandgap values with the Ho3+ ion substitution in NBT-BT was observed. Under the excitation of 532 nm light, the two most prominent red fluorescence emission peaks were emitted, where the first emission band with weak intensity was observed at 657 nm which corresponds to the 5F5→5I8 transition, and a strong 2nd peak at 756 nm corresponds to the 5F4/5S2→5I7 level transition of the Ho3+ ion. These findings provide a feasible multifunctional property in the applications of power electronic devices with lead-free NBT-BT ceramics via rare-earth substitution.

Effect of continuous rapid annealing on the microstructure and properties of Fe85P11C2B2 amorphous alloy

Fe-based amorphous alloys are promising soft magnetic materials for applications in power electronic devices. However, the practical use is inevitably limited by their brittleness that results from annealing. In this paper, an Fe85P11C2B2 amorphous alloy was heat treated by using a self-designed continuous rapid annealing equipment. After rapidly annealing the amorphous precursors at 773 K for 0.3 s, the α-Fe phase with a size of 2 ∼ 5 nm precipitated, and the ribbon sample exhibits a high saturation magnetization (Bs) of 1.66 T and low coercivity (Hc) of 7.6 A/m in combination with good bending ductility. This work will provide a new heat treatment method for the soft-magnetic Fe-based amorphous alloy that can inhibit annealing-induced brittleness.

Design of PFC with Buck Boost Converter for Plug- In Electric Vehicles and Battery Charging Applications

The wireless charging system working principle is same as transformer. It consists of transmitter and receiver, the AC supply is converted into high frequency alternating current, which is supplied to transmitter coil. Then it produces an alternating magnetic field which cuts the receiver coil and the receiver coil generates AC power output. The important thing in the wireless charging system is to maintain the resonance frequency between transmitter and receiver in order to make it effective. With the high modernization and electrification of industry, people now have a higher requirement for the power quality. For instance, personal computers, electronic devices, cell phones, they each has a basic requirement for power quality. Because of the wide application of power electronic devices, there are reactive power and harmonics in the power grid. The main research content of this paper is the design of boost power factor correction circuit and design of its control system. So we can conclude that the existence of harmonic current pollute power grid so much and we have to take some actions to eliminate or restrain harmonic current. Index terms- PFC, Buck Boost, MATLAB, Electric Vehicle, THD

Experimental Analysis of Transformer Core Vibration and Noise under Inter-Harmonic Excitation

With the wide application of power electronic devices and nonlinear loads, the resulting inter-harmonic pollution is becoming more and more serious in the power system. As important equipment in power systems, transformers have always been the focus of research. However, there are few studies on the abnormal increase in vibration and noise caused by inter-harmonic excitation. In this work, a transformer core vibration and noise measurement platform that can generate arbitrary inter-harmonic excitations was built. The real-time vibration displacement waveforms of the core model under normal and inter-harmonic conditions were experimentally measured as well as the surrounding noise level amplitude and spectrum analysis result. The influence law of excitation of intermediate harmonic content and frequency on core vibration displacement and surrounding sound pressure level was summarized. The work of this paper lays a theoretical foundation for studying the vibration and noise of power transformers and other equipment under inter-harmonics.

Simultaneously Enhanced Thermal Conductivity and Dielectric Breakdown Strength in Sandwich AlN/Epoxy Composites.

Polymer-based composites with high thermal conductivity and dielectric breakdown strength have gained increasing attention due to their significant application potential in both power electronic devices and power equipment. In this study, we successfully prepared novel sandwich AlN/epoxy composites with various layer thicknesses, showing simultaneously and remarkably enhanced dielectric breakdown strength and thermal conductivity. The most optimized sandwich composite, with an outer layer thickness of 120 μm and an inner layer thickness of 60 μm (abbreviated as 120-60) exhibits a high through-plane thermal conductivity of 0.754 W/(m·K) (4.1 times of epoxy) and has a dielectric breakdown strength of 69.7 kV/mm, 8.1% higher compared to that of epoxy. The sandwich composites also have higher in-plane thermal conductivity (1.88 W/(m·K) for 120-60) based on the novel parallel models. The sandwich composites with desirable thermal and electrical properties are very promising for application in power electronic devices and power equipment.

Research and Design of Aviation Active Power Filter Based on DSP

As the application of power electronic devices in aviation power system become more and more widely, the harmonic and reactive power problems are becoming more and more serious. Active power filter has become an important research direction of power electronics technology. In this paper, the harmonic harm and harmonic suppression methods are briefly described. Then the software and hardware of APF are designed. Finally, the system is simulated by Simulink, which proves the rapidity and accuracy of harmonic and reactive current detection and compensation.

Chemical composition tuning induced variable and enhanced dielectric properties of polycrystalline Ga2‐2xWxO3 ceramics

AbstractWe report on the tunable and enhanced dielectric properties of tungsten (W) incorporated gallium oxide (Ga2O3) polycrystalline electroceramics for energy and power electronic device applications. The W‐incorporated Ga2O3 (Ga2−2xWxO3, 0.00 ≤ x ≤ 0.20; GWO) compounds were synthesized by the high‐temperature solid‐state chemical reaction method by varying the W‐content. The fundamental aspects of the dielectric properties in correlation with the crystal structure, phase, and microstructure of the GWO polycrystalline compounds has been investigated in detail. A detailed study performed ascertains the W‐induced changes in the dielectric constant, loss tangent (tan δ) and ac conductivity. It was found that the dielectric constant increases with addition of W in the system as a function of temperature (25°C‐500°C). Frequency dependence (102‐106 Hz) of the dielectric constant follows the modified Debye model with a relaxation time of ∼20 to 90 μs and a spreading factor of 0.39 to 0.65. The dielectric constant of GWO is temperature independent almost until ∼300°C, and then increases rapidly in the range of 300°C to 500°C. W‐induced enhancement in the dielectric constant of GWO is fully evident in the frequency and temperature dependent dielectric studies. The frequency and temperature dependent tan δ reveals the typical behavior of relaxation loses in GWO. Small polaron hopping mechanism is evident in the frequency dependent electrical transport properties of GWO. The remarkable effect of W‐incorporation on the dielectric and electrical transport properties of Ga2O3 is explained by a two‐layer heterogeneous model consisting of thick grains separated by very thin grain boundaries along with the formation of a Ga2O3‐WO3 composite was able to account for the observed temperature and frequency dependent electrical properties in GWO. The results demonstrate that the structure, electrical and dielectric properties can be tailored by tuning W‐content in the GWO compounds.

Laser induced forward transfer of brittle Cu3Sn thin film

Abstract Cu3Sn intermetallic compound as an interconnecting material has great prospect in power electronic device applications due to its high melting temperature. However, the intermetallic compound is essentially brittle, and hard to be transferred. In this study, Cu3Sn thin films have been successfully transferred by means of laser-induced forward transfer (LIFT) process with millisecond pulse length. The morphology of LIFT-processed Cu3Sn thin film was investigated by optical microscopy and Atomic Force Microscopy (AFM). The optimized transfer process parameters were 0.3 ms laser irradiation, 8001100 W laser power and 14 mm defocusing amount. Under the optimized conditions, the deposition pattern of Cu3Sn thin films were complete and uniform. The transfer mechanism was that the solid Cu3Sn films have been pushed and transferred by the gasified part Cu3Sn near the interface of the donor substrate during the LIFT process.

Harmonic Source Region Location Based on Fast ICA and Scene Clustering

The widespread application of power electronic devices and renewable power generation has resulted in significant harmonic pollution. Harmonic source location is of great importance since it is a prerequisite to mitigate harmonic pollution. In this paper, a scene-based harmonic source region location method is proposed. The proposed method employs the fast independent component analysis (ICA) to locate the harmonic source region as the harmonic measurement matrix is unknown and the measuring equation is not observable. In this way, the range of suspect harmonic sources is narrowed and the cost of harmonic source location is reduced. Furthermore, the improved K-means algorithm is adopted to divide the measurement data into several scenes to improve location accuracy. Finally, a case study is conducted to verify the validity and accuracy of the proposed method.

Mitigation of power quality issues using UPQC

Abstract Power quality has become major concern these days due to application of power electronic devices. Conventional equipment like passive filter, segregate series and shunt filters and synchronous condenser etc. have become inadequate to mitigate different power quality problems. Since, power quality mainly concerned with voltage quality and the current quality in the system. For voltage quality, series compensator is used and for current quality, shunt compensator is used. Further, when these two power quality problems are mitigated simultaneously, the device, which is used, called unified power quality conditioner (UPQC), in power distribution system. In this paper voltage related power quality problems such as (voltage sag, voltage swell, voltage and current distortion) are discussed and UPQC controller is simulated to mitigate these problems. There are different control techniques available for UPQC. Here one of them i.e., unit vector template generation (UVTG) is used to simulate UPQC controller. The considered system efficiently regulated the DC link voltage using properly tuned PI parameters. The proposed work is also validated using experimental results.

Energy demand and quality management of standalone diesel/ PV /battery microgrid using reconfiguration

Power quality has become one of the most vital challenges in the planning of smart distribution grids due to popularity and myriad applications of power electronic devices. This paper introduces a new method based on network reconfiguration to efficiently deliver the energy demand of standalone Diesel/PV/Battery microgrids with improved power quality. The feeder reconfiguration is performed to decrease power loss, decrease the total harmonic distortion (THD), and improve voltage sag indices. Mathematical models of Diesel/PV/Battery standalone system are integrated with harmonic power flow algorithms to implement the concept. Reconfiguration algebraic equations along with nonlinearities introduced by Diesel/PV/Battery standalone system are solved by means of Non-Dominated Sorting Differential Evolution Algorithm (NDSDEA). The proposed methodology is carried out on a 33-bus standalone microgrid. The results have shown that reconfiguration not only improves the overall performance of the standalone energy system but also is effective to improve the quality of power delivered to the significant consumers. The method has both economic and technical benefits for such islanded networks.

Load modeling techniques in distribution networks: a review

Power system operation and control required models of generators, lines and loads to be accurately estimated, this is to enable operators make a reliable decision on the system. Generators and lines models are so far considered accurate, while load models are considered perplexing due to invention of new types of loads, distribution system are transforming from passive to active. Future distribution systems are desired to be smart and for a network to be smart the system as to be fully and accurately represented. Penetration of renewable energy and application of power electronic devices as well as participation of active customers in distribution systems make traditional methods of load modeling absolute. Accurate load modeling is required to address the new challenges evolving in the task of power system operation, control and stability studies. It is also an interest of power system researchers globally to realize Smart Networks (SNs), in which accurate load models are required. This work described a review of techniques and approaches for load modeling from traditional methods to the state of art in the area. In addition, gaps in the literature as well as research directions are also pointed out.

Low temperature electron mobility exceeding 104 cm2/V s in MOCVD grown β-Ga2O3

We report on record electron mobility values measured in lightly Si doped homoepitaxial β-Ga2O3 grown by metal-organic chemical vapor deposition. The transport properties of the films were studied using temperature-dependent Hall measurements. Numerous (010) β-Ga2O3 layers grown at different conditions showed peak electron mobility exceeding 104 cm2/V s at low temperature (LT), with the highest value of 11 704 cm2/V s at 46 K. The room temperature electron mobilities of the films were between 125 cm2/V s and 160 cm2/V s with the net background charge concentration between ∼5 × 1015 cm−3 and ∼2 × 1016 cm−3. The obtained LT mobility values for β-Ga2O3 were found to be comparable to or higher than the highest LT electron mobilities in bulk SiC and GaN films in the literature. The results demonstrate the capability of metalorganic chemical vapor deposition (MOCVD) for growing high quality ultrapure β-Ga2O3 epitaxial films that are suitable for high power electronic device applications.