High Power Switching Research Articles

Study of optimum control strategy for multiple pulse thyristor rectifiers

In order to control simply and reduce harmonic content, high-power DC switch power supply often uses sequential control. As the depth control has low power factor, we use sequential control in order to improve the power factor, but the network side current harmonic content is big in shallow control and will contribute much harmonic pollution to power grid. In this paper, by comparison and analysis of fundamental wave, harmonic wave, THD and power factor for input current from sequential control and synchronous control respectively, an optimum control theory which will decrease the harmonic and maintain the power factor is proposed. Tests proved that the optimum control strategy for multiple thyristor rectifiers will conduct sequential control when in depth control and conduct parallel control in shallow control and will achieve a lower harmonic content than complete order control with relatively the same power factor.

Study of optimum control strategy for multiple pulse thyristor rectifiers

In order to control simply and reduce harmonic content, high-power DC switch power supply often uses sequential control. As the depth control has low power factor, we use sequential control in order to improve the power factor, but the network side current harmonic content is big in shallow control and will contribute much harmonic pollution to power grid. In this paper, by comparison and analysis of fundamental wave, harmonic wave, THD and power factor for input current from sequential control and synchronous control respectively, an optimum control theory which will decrease the harmonic and maintain the power factor is proposed. Tests proved that the optimum control strategy for multiple thyristor rectifiers will conduct sequential control when in depth control and conduct parallel control in shallow control and will achieve a lower harmonic content than complete order control with relatively the same power factor.

Thermal performance evaluation of cascode Paralleled-GaN-HEMTs packaging for high power switching applications

This study investigated the heat generation behavior of normally-on GaN FET consisting of multi-chip AlGaN/GaN high electron mobility transistors (HEMTs) cascoded with a low-voltage MOSFET (LVMOS) and a SiC Schottky barrier diode (SBD) in a new design package to enable high power applications. The electric field intensity distribution and the hot spot position of the devices were analyzed by electrothermal simulation and the infrared temperature measurement. The transient thermal characteristics are probed by temperature sensitive parameters (TSPs). The changes in on-resistance (RON), maximum drain current (IDMAX), and transconductance (gm) with temperature from 25 °C to 150 °C are measured, and the correlations are investigated. Two paralleled GaN-HEMT, LVMOS, and SiC SBD were then integrated on a directly bonded copper (DBC) substrate in the four-pin metal case TO-257 and a newly designed REC-2015 package to evaluate steady thermal performance improvement of packaging. The temperature distribution of parallel-connected GaN HEMTs were analyzed in numerical thermal simulations and infrared thermography measurements. The analytical results of thermal analysis were confirmed by comparing with the infrared thermographic measurements and numerical results obtained from simulations using Ansys Icepak. According to the thermal measurement at power dissipation of less than 24 W, the peak temperatures of the GaN HEMTs are 144.7 °C and 132.6 °C with TO-257 and REC-2015 package.

Single Stage–Single Switch High Power Factor Long Lifetime AC-DC Driver for High-power White Light-emitting Diodes in Streetlight Applications

To achieve the main advantages of individual high-power white light-emitting diodes, light-emitting diode drivers should feature a high power factor, high efficiency, and a long lifetime. In streetlight applications, due to the inconvenience in reaching out to light-emitting diode fixtures for replacing out-of-order drivers, the durability (long lifetime) of drivers plays an important part in designing lighting products. In this article, a new integrated, single-stage single-switch AC-DC driver for high-power white light-emitting diodes featuring high efficiency, a high power factor, and a long lifetime for streetlight applications is proposed. The single power switch of the proposed driver operates in a non-floating manner without a need for any snubber circuits due to proper inherent operation, which makes the driver simple and reliable. To verify accurate operation of the driver as well as validate the analysis and design procedure discussed herein, a 35-watt light-emitting diode fixture is first simulated in PSIM software (PowerSIM Inc., USA), and then a laboratory prototype is implemented. Simulation and experimental results verify proper performance, high input power factor, and validity of the analysis and the design procedure adopted in the process.

Identification of Novel Short BaTiO3-Binding/Nucleating Peptides for Phage-Templated in Situ Synthesis of BaTiO3 Polycrystalline Nanowires at Room Temperature.

Ferroelectric materials, such as tetragonal barium titanate (BaTiO3), have been widely used in a variety of areas including bioimaging, biosensing, and high power switching devices. However, conventional methods for the synthesis of tetragonal phase BaTiO3 usually require toxic organic reagents and high temperature treatments, and are thus not environment-friendly and energy-efficient. Here, we took advantage of the phage display technique to develop a novel strategy for the synthesis of BaTiO3 nanowires. We identified a short BaTiO3-binding/nucleating peptide, CRGATPMSC (named RS), from a phage-displayed random peptide library by biopanning technique and then genetically fused the peptide to the major coat protein (pVIII) of filamentous M13 phages to form the pVIII-RS phages. We found that the resultant phages could not only bind with the presynthesized BaTiO3 crystals but also induce the nucleation of uniform tetragonal BaTiO3 nanocrystals at room temperature and without the use of toxic reagents to form one-dimensional polycrystalline BaTiO3 nanowires. This approach enables the green synthesis of BaTiO3 polycrystalline nanowires with potential applications in bioimaging and biosensing fields.

Performance Characteristics and Preliminary Analysis of Low Cost Tubular Linear Switch Reluctance Generator for Direct Drive WEC

This paper presents the performance characteristics of a low cost but high-power density tubular linear switch reluctance generator (TLSRG) for direct drive marine wave energy conversion (WEC). The presented TLSRG consists of series of soft magnetic rings and exhibits higher power density than conventional teeth type TLSRG. There is sole set of round winding in each stator slot, which facilitates manufacturing process, thus, results in low cost. The referred ring segments are both magnetically and electrically isolated with each other so it reduces the phase coupling and increase the capability of fault tolerance that is favorable to be used in harsh conditions as WEC. The characteristics and dynamic performance at WEC mode are examined and discussed, validating that the presented TLSRG is a strong alternative candidate to permanent magnet tubular generator for WEC.

(Invited) Current Topics in Electronic Devices Based on Wide Band-Gap Semiconductors for Power Applications and Energy Efficiency

Wide-bandgap power semiconductor devices offer enormous energy efficiency gains in a wide range of potential applications. As silicon-based semiconductors are fast approaching their performance limits for high power requirements, gallium nitride (GaN), silicon carbide (SiC), and diamond, with their superior electrical properties are likely candidates to replace silicon in the near future. Along with higher blocking voltages wide-bandgap semiconductors offer breakthrough relative circuit performance enabling low losses, high switching frequencies, and high temperature operation. The progress of the development of high voltage, high current wide-bandgap power switching devices in the APRA-E SWITCHES program is reviewed. The performance of various rectifiers and transistors, which have been demonstrated, is discussed. Material and processing challenges and reliability concerns for wide-bandgap power devices are also described. A glimpse into the future trends in device development and commercialization is offered.

Influence of Channel Length and High-K Oxide Thickness on Subthreshold DC Performance of Graded Channel and Gate Stack DG-MOSFETs

Comparative assessment of graded channel gate stack (GCGS) DG MOSFET structure is done by using two-dimensional (2D) Sentrausu TCAD simulator for different high K oxide thickness. This novel device includes gate stack (GS) engineering (high K) and nonuniformly channel engineering (GC) to suppress the short channel effects and improve the device performance. This novel device can be a better alternative for the future high speed switching and low power circuit applications. It has the advantage of improved breakdown voltage, reduced leakage current, low output conductance and reduced bipolar parasitic effects. The given device must be properly investigated with respect to the variation of different high K oxide thickness on different parameters such as drain induced barrier lowering (DIBL), subthreshold slope (SS), [Formula: see text]/[Formula: see text], [Formula: see text] roll off before fabrication to have better reliability. The 2D Sentrausu TCAD simulator using drift-diffusion model was used to simulate the developed structure and good agreement is obtained with respect to already published result in the sub-threshold regime. The result indicates that there is a need to be optimize the DC parameters for specific circuit applications.

(Invited) Current Topics in Electronic Devices Based on Wide Band-Gap Semiconductors for Power Applications and Energy Efficiency

Wide-bandgap power semiconductor devices offer enormous energy efficiency gains in a wide range of potential applications. As silicon-based semiconductors are fast approaching their performance limits for high power requirements, gallium nitride (GaN), silicon carbide (SiC), and diamond, with their superior electrical properties are likely candidates to replace silicon in the near future. Along with higher blocking voltages wide-bandgap semiconductors offer breakthrough relative circuit performance enabling low losses, high switching frequencies, and high temperature operation. The progress of the development of high voltage, high current wide-bandgap power switching devices in the ARPA-E SWITCHES program is reviewed. The performance of various rectifiers and transistors, which have been demonstrated, is discussed. Material and processing challenges and reliability concerns for wide-bandgap power devices are also described. A glimpse into the future trends in device development and commercialization is offered.

Development of a prototype T-shaped fast switching device for electron cyclotron current drive systems

A T-shaped high-power switching device composed of circular corrugated waveguides with three ports and double dielectric disks made of sapphire was proposed as a fast switching device based on a new principle in electron cyclotron current drive systems. This switching device has the advantages of operating at a fixed frequency and being compact. The design of the prototype switch was obtained by numerical simulations using a finite-difference time-domain (FDTD) method. The size of these components was optimized for the frequency band of 170 GHz. Low-power tests were carried out in a cross-shaped model.

Design and fabrication of a 1.2 kV GaN‐based MOS vertical transistor for single chip normally off operation

We report a novel design to achieve normally off, high voltage power switch using an “all‐GaN” vertical MOS‐gate transistor (MOSVFET). In this structure, two MOS gates were formed vertically on the sidewalls of the pillar, whose opposite ends were connected to the source and drain of the device. The design space and associated performance based on 2D drift‐diffusion model is discussed highlighting the trade‐off between blocking voltage (Vbl), on resistance (Ron), and threshold voltage (Vth). An optimized device structure was proposed with more than 1.2 kV blocking capability and normally off behavior. With proper design of the drift region thickness and doping, the corresponding Ron was as low as 2.8 mΩ cm2. The role of key parameters such as bulk GaN mobility, channel mobility, gate to gate distance (Lgtg) and gate length (Lg) on the Ron, Vbl, leakage current, and Vth were also examined. The effect of mobility on the device performance and the role of the bulk GaN material was analyzed utilizing the model to create a comprehensive design space for achieving low‐loss switching.

Design for boost DC-DC converter controller based on state-space average method

abstractThe accurate mathematical model of converter is very important in the process of designing high performance switch power. Nonlinear, multimodal and time-varying are the characteristics of the DC-DC converter. So it is necessary to study it in a new way. This paper presents a mathematical model of Boost converter circuit by state space average method. The closed-loop PI controller based on the Boost converter model was designed. The static and dynamic performance of the closed-loop system was tested in Simulink which demonstrated a good behavior of the system to meet the requirements of user.

Effects of the Effect of Ultra High Frequency Mobile Phone Radiation on Human Health.

IntroductionPublic and occupational exposure to electromagnetic fields due to the growing trend of electronic devices may cause adverse effects on human health. This paper describes the risk of mutation and sexual trauma and infertility in masculine sexual cell by mobile phone radiations.MethodsIn this study, we measured the emitted dose from a radiofrequency device, such as switching high voltage at different frequencies using a scintillation detector. The switching high voltage power supply (HVPS) was built for the Single Photon Emission Computed Tomography (SPECT) system. For radiation dosimetry, we used an ALNOR scintillator that can measure gamma radiation. The simulation was performed by MATLAB software, and data from the International Commission on Non-Ionizing Radiation Protection (ICNIRP) were used to verify the simulation.ResultsWe investigated the risks that result from the waves, according to a report by International Commission on Non Ionizing Radiation Protection (ICNIRP), to every organ of the body is defined by the beam and electromagnetic radiation from this electronic device on people. The results showed that the maximum personal dose over a 15-min period working at the mentioned HVPS did not exceed 0.31 μSV/h (with an aluminum shield). So, according to other sources of radiation, continuous working time of the system should not be more than 10 hours. Finally, a characteristic curve for secure working with modules at different frequencies was reported. The RF input signal to the body for maximum penetration depth (δ) and electromagnetic energy absorption rate (SAR) of biological tissue were obtained for each tissue.ConclusionThe results of this study and International Commission of Non Ionization Radiation Protection (ICNIRP) reports showed the people who spend more than 50 minutes a day using a cell phone could have early dementia or other thermal damage due to the burning of glucose in the brain.

On the construction of power quality control systems

Some aspects of the construction of power quality control systems in power supply systems are discussed. The basic requirements for quality factors of electric power are determined, the conditions of joint parallel operation of energy consumers are considered, and analysis of traditional ways of solving the emerging problems is carried out. The advantages and disadvantages of power quality control systems related to the capabilities of new technologies with application of high-power semiconductor switching devices (GTO and IGCT thyristors, MOSFET and IGBT transistors) are considered. The application of computer technology in power quality control systems makes it possible to use rather complicated and effective algorithms of numerical processing of signals and significantly increase the accuracy of correction of disturbances in electric networks. The advantages and disadvantages of industrial plants constructed in the form of a controlled reactor with a dc magnetic bias and a reactor with a thyristor key are considered. Two types of devices to compensate for possible disadvantages are identified: devices using fully controlled keys and devices ones using artificial commutation and incompletely controlled power keys. A brief analysis of the known methods of electric power quality control is implemented. Recommendations for the establishment of power quality control systems are suggested in which the parameters of software depend on the solution algorithm of a posed problem, while the algorithm itself depends on the method of control and mathematical laws on which it is based. The method of control determines the structure of the power quality control system, while the software determines the basic operations of information processing, their quantity, the scheme of data processing, the volume data flows, etc.

Study on the high-power semi-insulating GaAs PCSS with quantum well structure

A high-power semi-insulating GaAs photoconductive semiconductor switch (PCSS) with quantum well structure was fabricated. The AlGaAs layer was deposited on the surface of the GaAs material, and the reflecting film and the antireflection film have been made on the surface of the GaAs and AlGaAs, respectively. When the prepared PCSS worked at a bias voltage of 9.8 kV and triggered by a laser pulse with an incident optical energy of 5.4 mJ, a wavelength of 1064 nm and an optical pulse width of 25 ns, the on-state resistance of the AlGaAs/GaAs PCSS was only 0.45 Ω, and the longevity of the AlGaAs/GaAs PCSS was larger than 106 shots. The results show that this structure reduces the on-state resistance and extends the longevity of the GaAs PCSS.

Research on a Novel High-Power Semi-Insulating GaAs Photoconductive Semiconductor Switch

A photoconductive semiconductor switch (PCSS) with a gap of 10 mm was fabricated from 0.6-mm deep semiinsulating GaAs. The reflecting film has been made on the electrode surface, and the antireflection film has been made on the opposite surface. The PCSS was triggered by a laser pulse with an incident optical energy of 5.4 mJ, a wavelength of 1064 nm, and an optical pulsewidth of 25 ns. At a bias voltage of 6 kV, the calculated ON-state resistance of the PCSS with a reflecting film and an antireflection film was only 0.61 Ω. To increase the photocurrent of the PCSS, a PCSS with an interdigital electrode has been made, at a bias voltage of 2 kV, and the ON-state resistance was 0.35 Ω.

Nanocarbon synthesis by high-temperature oxidation of nanoparticles.

High-temperature oxidation of silicon-carbide nanoparticles (nSiC) underlies a wide range of technologies from high-power electronic switches for efficient electrical grid and thermal protection of space vehicles to self-healing ceramic nanocomposites. Here, multimillion-atom reactive molecular dynamics simulations validated by ab initio quantum molecular dynamics simulations predict unexpected condensation of large graphene flakes during high-temperature oxidation of nSiC. Initial oxidation produces a molten silica shell that acts as an autocatalytic ‘nanoreactor’ by actively transporting oxygen reactants while protecting the nanocarbon product from harsh oxidizing environment. Percolation transition produces porous nanocarbon with fractal geometry, which consists of mostly sp2 carbons with pentagonal and heptagonal defects. This work suggests a simple synthetic pathway to high surface-area, low-density nanocarbon with numerous energy, biomedical and mechanical-metamaterial applications, including the reinforcement of self-healing composites.

First Principle Analysis of (10-Boranylanthracene-9-yl)borane-Based Molecular Single-Electron Transistor for High-Speed Low-Power Electronics

A molecular single-electron transistor (SET) with (10-Boranylanthracene-9-yl)borane molecule as an island has been analyzed in an effort to model a better acene series SET. The (10-Boranylanthracene-9-yl)borane molecule was obtained through the substitution of dangling hydrogens of middle honeycomb by boron in anthracene. A first principle analysis has been performed to analyze the impact of boron substitution in anthracene and on the SET performance using density functional theory (DFT)-based ab initio tools Atomistix Toolkit-Virtual Nanolab and Gaussian03. To analyze the impact of boron substitution, different structural and electronic properties, such as electron density difference, natural bond orbital analysis, electron localization function, molecular energy spectrum, total energy, bond lengths, and bond angles, have been calculated, and to analyze the device performance, charging energies have been calculated and plotted total energies, charge stability diagram as a function of bias potentials. The analysis confirms that the proposed doped anthracene-based SET has high switching speed and power efficiency in comparison with the other organic molecular SETs reported of the kind.

Robust Stability Analysis of Active Voltage Control for High-power IGBT Switching by Kharitonov's Theorem

The main idea of active voltage control (AVC) is to employ classic feedback-control methods forcing the IGBT collector voltage transient to follow a predefined trajectory. This feedback control of IGBTs has great advantages in guaranteeing that IGBTs remain in safe operating area (SOA), restricting EMI, mitigating the voltage/current stress, minimizing/predicting their power losses, and balancing voltages of IGBTs in series. Inevitably, however, AVC introduces stability issues. Based on the assumption that accurate IGBT small-signal model parameters are available, an analogue proportional-derivative and multiloop feedback control was proposed to achieve stable performance in previous work. Due to nonlinearities and uncertainties in IGBT parameters, previous stability analysis methods have important limitations. This work uses Kharitonov's theorem during the IGBT controlled turn-off to assess the system's stability and guide the AVC design to account for model uncertainties and varying parameters. We conducted experiments to investigate the system's robust stability due to these uncertainties in the IGBT parameters, which confirm the validity of the proposed theoretical analysis. With the use of wide bandwidth op-amps, it is shown that the feedback design may be simplified.

High-Power Thyristor Switching via an Overvoltage Pulse with Nanosecond Rise Time

High-power thyristor switching from the blocking to conducting state via an overvoltage pulse with nanosecond rise time is studied. Low-frequency tablet thyristors with an operating voltage of 2 kV are used in the experiments. An external pulse providing a voltage rise rate from 0.5 to 6 kV/ns was applied to the thyristors main electrodes. Under these conditions, the time of thyristor switching to the conducting state is 200–400 ps. Empirical relations between the main switching characteristics, i.e., the turn-on voltage, pulse rise time before switching, and time of thyristor switching to the conducting state, are obtained. Numerical simulation shows that the ionization of deep technological defects should be taken into account to explain the results obtained.