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High voltage direct current (HVdc) detection is essential to ensure the suitability and operation of electrical systems, as well as personal safety. Today there are commercial sensing devices equipped with a safety system that emits audible warnings, but they do not indicate voltage and polarity levels. Likewise, although the scientific literature describes various solutions with satisfactory results, very few of these achievements are found in real-world applications. The purpose of this article is to present a technological alternative based on the study and development of a simple and portable electronic device to enable the detection and quantification of high voltage and polarity in HVdc systems. The principle is based on the detection of corona current by means of an aluminum tip held at a distance of about 5 mm from the energized surface through a radial contact rod. The detected electrical current signal is collected and processed through an electronic system. The performance was analyzed by means of corona discharge models and high voltage experimental tests in real-world conditions. The results demonstrated the satisfactory response of the proposed approach in the detection, quantification, and identification of polarity in a ±600 kV HVdc transmission system, with an error varying from 1.79% to 2.72% compared to theoretical values, as well as its ability to withstand the influence of temperature variations between 18 °C to 29 °C, relative humidity between 56% and 78%, and an atmospheric pressure kept constant at 101.6 kPa. The proposed approach contributes to HVdc monitoring and inspection activities, helping to ensure their operation and suitability. [ABSTRACT FROM AUTHOR]

Impedance-based approachis generally studied for stability analysis of the power electronic converter-based system. Considering multiple-frequency coupling effects, in this article, we establish the harmonic transfer function (HTF) based αβ-frame impedance models of droop inverters based islanded microgrid with unbalanced loads. Therein, the HTF-based αβ-impedance modeling methods of unbalanced loads, as well as droop inverters in parallel, are proposed. Afterward, the HTF-based αβ-frame impedance models are equivalent to single-input single-output (SISO) impedances for simpler impedance measurement and stability analysis, preserving the αβ-frame coupling and multiple-frequency coupling characteristics. Finally, the experimental measurement results verify the accuracy of the αβ-frame SISO impedances. Besides, the stability analysis based on the SISO impedance models accurately reveals low-frequency oscillations of the islanded microgrid with unbalanced loads, further verifying the effectiveness of the SISO impedance models. [ABSTRACT FROM AUTHOR]

This article presents the analysis and design of a single-stage charge-pump (CP) bridgeless converter for light-emitting diode (LED) applications. The proposed topology is based on a boost bridgeless converter operating in a discontinuous conduction mode, which is associated with the CP concept. The proposed electronic lighting system employs a reduced component count, and the CP concept is used to reduce the LED current ripple. A high power factor is demonstrated to be an inherent property of the proposed topology, and no input current control is necessary. The operating principle of the proposed converter, which includes two operating modes in a steady state, is presented and analyzed. We also present a prototype operating with a switching frequency of 75 kHz, an input voltage range of 90–160 VRMS, and an output power of 60 W with a power factor of 0.989, the total harmonic distortion of 14.15%, and the efficiency of up to 95.4%. Additionally, all individual harmonic magnitudes of the input current meet the IEC 61000-3-2 class-C standard limits. [ABSTRACT FROM AUTHOR]

The trend toward higher switching frequency and larger scale of power electronic systems poses challenges for real-time simulation. This article presents an event-driven hardware-in-the-loop (ED-HIL) simulation framework that does not rely on the small fixed simulation step-size related to the switching frequency. ED-HIL framework can improve the calculation efficiency by positioning switch events and using variable simulation step-size. Further, a parallel acceleration and circuit partitioning (PACP) solver is proposed based on this framework. The PACP solver partitions the circuit with energy storage elements and ensures that the partitioning does not introduce simulation distortion by using the higher order derivatives of the energy storage elements. Meanwhile, it achieves a process-level paralleling through a shared memory architecture in order to accelerate the simulation. As a result, the proposed PACP solver based on the ED-HIL framework can achieve about three times the simulation scale of a commercial FPGA-based real-time simulator at 1/16 the hardware cost under the same conditions. An accurate real-time HIL example of a power electronic transformer with 32 switches at a switching frequency of 20 kHz has been implemented on a personal computer. The simulation results are analyzed by comparing with experiment, offline software, and commercial real-time simulator. [ABSTRACT FROM AUTHOR]

This article presents a discrete convolution-based method for reliability evaluation of a grid-connected photovoltaic (PV) system, where special consideration is given to the variable availability of PV array components. Along with the negative impacts of variable solar irradiance and ambient temperature on the PV power generation, they affect the reliability of PV system power electronic components. A variable availability model based on the power loss in the semiconductors of PV system components is needed to account for this effect in the reliability analysis. The article proposes a 3-D capacity outage model of a PV farm that accounts for the variable availability and the redundancies associated with the topologically complex multistring PV arrays. The outage model is used to construct a PV capacity outage probability and frequency table (COPAFT), which along with conventional generation COPAFT, is convolved with the distribution of load to determine system reliability. An integration limit assessment tool is also developed within the proposed framework, ensuring that the PV power integration does not violate the system frequency stability. Simulations on the modified IEEE RTS-79 system demonstrate the efficacy of the proposed method. [ABSTRACT FROM AUTHOR]

With the increasing demand for high-performance power electronic systems, the semiconductor device utilization has gained significant importance. This article proposes the Si/SiC devices based active neutral-point-clamped converter comprising SiC-based H-bridge structure. A novel pulsewidth modulation (PWM) scheme is also proposed that results in an effective utilization of the switching devices. In the proposed converter, the Si devices are soft-switched for all power-factor loading conditions. Therefore, high efficiency can be obtained even at high switching frequency operation with wide range of power factor values. Further, the conduction losses of the SiC mosfets are minimized by strategically selecting the switching states in such a way that the SiC mosfets conduct in parallel conduction paths during the null state operation. This leads to further enhanced efficiency. This article presents the detailed operating principle of the proposed topology operated with the presented PWM scheme. Moreover, a device loss analysis is presented to evaluate the conduction and switching losses of the proposed topology. The presented experimental results validate the performance parameters of the proposed topology with the proposed PWM scheme. Finally, the proposed PWM scheme is compared with the existing PWM schemes using efficiency values of the proposed and some of the prominent existing converter configurations. [ABSTRACT FROM AUTHOR]

Reliability evaluation of electronic systems in space environment is a critical issue. In this work, reliability evaluation of superluminescent diode (SLD) systems, which are sensitive to both displacement damage effects and charge–discharge effects, was investigated by the Bayesian network model. Displacement equivalence model of the SLDs is verified by the irradiation results of 5-MeV protons and 1-MeV electrons. Charge–discharge effects of SLDs are induced by 110-keV electrons. Orbital energy spectra and cumulative distribution functions for the equivalent irradiation fluence are calculated by self-built software. Based on the experimental and calculated results, the Bayesian networks under various conditions are established. The probabilities of the type of faults prone in the system under each condition can then be analyzed and quantified. The proposed method provides a good idea for on-orbit reliability evaluation of complex systems. [ABSTRACT FROM AUTHOR]

Research works on high-altitude electromagnetic pulse (HEMP) have attracted considerable attentions for its ability to disturb or damage the electronic and power systems. HEMP can be divided into the following three parts: early-time (E1), intermediate-time (E2), and late-time (E3). Most of the studies of HEMP are focused on E1, and few investigations have been done on E2 in the open literatures. However, the amplitude of E2 is about 10–100 V/m, and it is able to couple into the cables whose lengths are several kilometers. Therefore, E2 is also a threat to power systems. The simulation of E2, which can provide more accurate environmental parameters for research works on HEMP interactions with systems, is an important supplement to HEMP simulation. In this article, a numerical simulation method of E2 is presented which combines the Monte Carlo transport code and the 2-D EMP code to simulate both E1 and E2. In addition, the simulation results of E2 are given which are in qualitative agreement with the standard waveform. This work is helpful to fill the gap in the simulation of E2 at present and to simulate HEMP environment more accurately and completely. [ABSTRACT FROM AUTHOR]

A fault-tolerant control (FTC) is proposed for enhancing the reliability of power electronic systems. The software-based FTC of parallel-connected three-level T-type converters (3LT2Cs) for suppressing zero-sequence circulating current (ZSCC) induced by a vertical switch open-circuit fault is investigated. A simplified sequential model predictive control (SSMPC)-based FTC technique is developed. Parallel-3LT2Cs and their prediction models are introduced, followed by an SSMPC for the no-fault condition. The model inaccuracies under vertical switch faults are elaborated. For the faulty 3LT2C, two fault-tolerant SSMPC (FT-SSMPC) methods are provided by creating a sequential predictive controller that considers ZSCC suppression and grid current tracking. The control policies for the ZSCC are changed from the standard feedback-free to feedback-based cost function (CF) optimization using the unimproved FT-SSMPC. Furthermore, an improved FT-SSMPC is proposed using a phase-deficient CF, which increases the accuracy of the mathematical relation of the fault condition. After fault diagnosis, the proposed method achieves neutral-point voltage balance and excellent point-of-common-coupling current, effectively suppresses the ZSCC, and increases the control reliability. Finally, experiments demonstrate the effectiveness of the proposed FT-SSMPC under various conditions. [ABSTRACT FROM AUTHOR]

Three-phase four-leg voltage-source inverter has been extensively investigated in recent years for its compactness, small size, and high efficiency, and it has been proved to be the best solution for providing transformer-less neutral connection to three-phase asymmetric loads. The main purpose of this article is to apply 3-D unbalanced coordinate transformation to the four-leg inverter, which supplies stand-alone asymmetric loads, to maintain the balance of the output capacitor voltages, and obtain simpler control structure and better control performance. First, a double closed-loop PI control structure can be designed based on the Clarke and Park transformations. Second, the phases and amplitudes of the capacitor voltages are locked based on the 3-D unbalanced coordinate transformation. Furthermore, the Clarke transformation oriented on the inductor currents is replaced by a 3-D unbalanced coordinate transformation, and the corresponding unbalance indices are continuously adjusted according to the unbalance indices of the capacitor voltages, so as to recover the capacitor voltages to the balanced condition. The simulation and experimental results of the whole control system for the four-leg inverter are provided in the end, so as to verify the feasibility and effectiveness of the 3-D unbalanced coordinate transformation for application to the power electronic systems. [ABSTRACT FROM AUTHOR]

Active electromagnetic interferences (EMI) cancellation is a promising solution to reduce the size of passive filters. Power electronic systems may generate periodic disturbances if they are controlled by periodic signals in steady-state operation. Periodic disturbances can be represented by a set of sine waves, according to the Fourier theory, and can be suppressed by an appropriate set of cancelling sine waves injected into the system. Since bothersome effects, like delay times or complex transfer functions, can be compensated by individually selecting the appropriate amplitude and phase for each cancelling sine wave, high EMI reductions can be achieved in a wide frequency range. In this contribution, this cancellation method is applied to the common-mode EMI of a three-phase motor inverter in stationary operation with periodic control signals in the frequency range from 150 kHz to 30 MHz. Approximately 2.4 million harmonics are suppressed. The characteristics of the overall system are discussed and the challenges for the cancellation system are elaborated. A method for the synthesis of the cancellation signal is introduced. The design of the cancellation system is described, and its signal processing is presented. The outstanding performance is proven by reference measurements in a laboratory setup. Extensions for practical applications are discussed. [ABSTRACT FROM AUTHOR]

Power electronic systems employing wide-bandgap GaN transistors promise high efficiency operation and power density but require minimized parasitic circuit elements and an effective cooling concept. This article presents a half-bridge module integrating two 600 V/170 mΩ gallium nitride (GaN) high-electron mobility transistors with their gate drive stages and a fraction of the dc-link capacitance on a patterned multilayer polycrystalline AlN-substrate. The high-voltage isolation at a layer distance of 10 μm and a dense chip-by-chip integration on the GaN half-bridge module enable a compact lateral commutation loop design combined with improved cooling capability of the power transistors. Consequently, the GaN half-bridge module allows for higher load currents at lower device temperature while most parasitic circuit elements are reduced compared to a conventional printed circuit board (PCB) design. The parasitic circuit elements of the GaN half-bridge module and a reference four-layer PCB half-bridge are evaluated using 3D-FEM field simulation and in-circuit measurements. Selected finite element method (FEM) simulation results are validated by S-parameter measurements and further used to parametrize a lumped commutation loop model. The thermal characterization of the GaN half-bridge module validates the improved cooling capability of the GaN half-bridge power module. Transient switching characteristics are studied in hard-switching mode. The device temperature and converter efficiency are evaluated in dc/dc buck-converter operation. [ABSTRACT FROM AUTHOR]

Due to the successive switching actions in a power electronic system, considerable conducted electromagnetic interference (EMI) is generated. This has been a major concern in designing power converters, which requires additional EMI filtering efforts. Passive EMI filters are the most common solutions to EMI reduction but usually consume a large portion of the volume as well as weight in power converters. Active EMI filters (AEFs) or hybrid EMI filters (HEFs) are considered best candidates over traditional passive EMI filters to achieve higher power density in power converters. The utilization of current transformer to sense or to compensate the EMI noise can increase the volume of an AEF. In this article, a transformer-less AEF, sprung from the concept of virtual impedance enhancement, is proposed. The proposed design features feedforward control with current-sensing-voltage-compensating. The operation principle of the proposed AEF is thoroughly introduced, and its performance is evaluated through simulations and experiments. Experimental results with an ac–dc power converter and a dc–ac inverter show that the proposed AEF can be generally applied to reduce conducted EMI on either ac or dc power lines. [ABSTRACT FROM AUTHOR]

Electrical connectors play an indispensable role in electrical and electronic systems. The frequently occurred intermittent failure events seriously affect the reliability of application systems. In this article, the repetitive mechanical insertion and withdrawal experiment of electrical connector is carried out by using our designed test rig and the intermittent failure phenomena recurs. The typical waveforms of contact resistance and force during the mating operation are presented. The variation laws of static contact resistance and dynamic contact resistance under intermittent failure condition are counted and analyzed. And the dynamic contact resistance is proven to be a suitable sensitive parameter to characterize the intermittent failure event. Based on the mathematical model, variation of surface morphology, and element analysis, the failure mechanism of electrical connectors under repetitive operation is proposed. [ABSTRACT FROM AUTHOR]

The vehicle industry’s primary theme is the increase in automating and integrating more robust intelligent electronic systems to transform towards Industry 4.0, enhance safe functioning with more flexibility, and extend the virtual productive age of the vehicular systems. Further, significant efforts focus on developing monitoring systems for abnormal driving conditions such as wheel spinning and sliding that can increase the operating environment’s hazards and speed up the wearing-off process. Thus, these events play a primary role in influencing the safety of the involved humans and determining the vehicle’s lifespan and the incurred maintenance costs because of the encumbrances by the generated vibrations and shocks. However, the existing measurement systems are not entirely digitized, and their initial development did not concern the concept of functional safety like redundancy to be used in safety-critical environments. Further, the current systems depend on a costly sensory system that requires strict and complex installation procedures. Therefore, the prevention of wheel spinning and sliding events by a safety-related miniaturized digital intelligent monitoring system comes to a corresponding meaning. Accordingly, this research work investigates the development of a novel safety-related platform following the standard IEC 61508 for monitoring and controlling abnormal driving conditions through vibration sensors incorporated with rotation sensors. The research work tests the novel system on a prototype vehicle where the conducted experiments prove the system’s capability to detect the events with reasonable accuracy. Further, this novel approach’s evaluation shows that the system represents a significant enhancement for various similar researches and applications. [ABSTRACT FROM AUTHOR]

High-frequency (HF) litz wires are increasingly used to increase the power density of power electronic systems. The wires installed in such applications consist of several hundreds or even thousands of strands sophistically twisted on multiple geometry levels. The novelty of the presented impedance extraction approach lies in a significant reduction of the calculation effort and the resolution of the litz wires with high copper fill factors (up to more than 60%) by a new multilevel Voronoi approach. The speedup is realized by a geometry-based restriction of the calculation of the inductive coupling of strand section pairs. The calculation of large coupling matrices can, therefore, be bypassed by a direct evaluation of sparse inductance matrices of lower dimension. Combined with an efficient implementation, the new sparse strand element equivalent circuit method requires less than 10% of RAM and only 0.1% of CPU time for the impedance extraction compared to the established partial element equivalent circuit method for high-frequency litz wires. Benchmarks with this established method demonstrate less than 1% deviation for the frequency-dependent impedances up to 1 MHz. [ABSTRACT FROM AUTHOR]

Packaging radio-frequency microelectromechanical systems (RF-MEMS) is mandatory for their integration in electronic systems. This paper discusses the integration of a Au−Ru/AlCu contact in a MEMS fabrication process with a wafer-level packaging (WLP) step through Al−Ge eutectic bonding. The Au contact is embedded in a movable fixed−fixed beam made of $30 ~ \mu \text{m}$ thick Si while Ru is used as a coating metal on top of the AlCu static electrode. The measured return loss and isolation of the contact, up to 40 GHz, are $\geq -1.7$ and $\leq -12$ dB respectively. The WLP Au−Ru/AlCu contact has an electrical resistance $\leq 1.2 ~ \Omega $ up to 3 million cycles in hot switching at 0.1 W before failing due to high electrical resistance. Au hillocking is identified as the only intrinsic limiting mechanism that can be mitigated by an appropriate design rule. It is demonstrated that Au−Ru/AlCu is a promising contact configuration, compatible with Al−Ge eutectic bonding, and can be integrated in a standard MEMS fabrication process flow for the development of a robust generation of WLP RF-MEMS. [ABSTRACT FROM AUTHOR]

Serial communication buses are used in electronic systems to interconnect sensors and other devices, but two of the most widely used protocols, i.e., interintegrated circuit (I2C) and serial peripheral interface (SPI), are vulnerable to bus-wide failure if even one device on the bus malfunctions. For aerospace applications demanding increasingly more distributed processing and sensing capability, the compounding risk to system reliability as device count scales becomes a limiting factor in mission scope, performance, and lifetime. We propose a simple external circuit to be added to each node on a communication bus that automatically isolates the node in the event of device failure. By automatically isolating failed devices, the integrity of the bus is preserved without requiring additional signals or processing overhead from the host controller. In this article, I2C and SPI isolation circuits are simulated, fabricated, and experimentally verified to be effective at preserving bus integrity in the event of peripheral device failure. The isolation circuits were integrated into three spacecraft for the successful NASA V-R3x mission and found to significantly improve system reliability by eliminating single-point failure modes of the I2C and SPI buses. The developed protection schemes are a valuable tool for decoupling system reliability from serial bus device count and can readily be integrated into the existing aerospace systems. [ABSTRACT FROM AUTHOR]

The coupling of short wavelength electromagnetic (EM) interference to critical electronic systems in highly reverberant enclosures is a growing concern in the EM interference/compatibility community. In such highly reverberant cavities, prior research has shown that the induced EM fields, voltages, or currents can be modeled using the wave-chaotic random coupling model (RCM). The RCM partitions the interaction within the cavity into a universally fluctuating part, derived from random matrix theory, and a system-specific part, defined by the radiation impedance of the ports of interest, where the voltages or currents are induced. Earlier researchers have treated the radiation impedance as a time-invariant, frequency-dependent complex quantity. This is true for passive structures but is not true for active semiconductor devices, such as microcontrollers, which can exhibit time-varying radiation properties depending on the instruction cycle being executed at a given instant of time. The estimate of such a time-varying radiation impedance and its correlation with instruction cycles in an elemental microcontroller is the focus of this work. Utilizing clustering algorithms, we observe that the measured radiation impedance, as well as radiative emissions, are correlated to the class of instruction cycles being executed. By clustering the radiation impedance and emissions of the general-purpose input/output ports utilizing the class of instructions being executed, predictive models for microcontroller susceptibility can be derived even when detailed knowledge of the specific instruction cycle being executed is unknown a priori. Such a predictive capability can find multiple applications in the EMI/EMC community. [ABSTRACT FROM AUTHOR]

The control of very high switching frequency power electronic converter systems featuring latest generation wide bandgap devices requires current measurements with a very high bandwidth (BW) to achieve high closed-loop control dynamics. One example is an ultrahigh BW $\mathbf {4.8}$ MHz parallel-interleaved multilevel GaN inverter ac power source with a target large-signal output BW of $\mathbf {100}$ kHz. This work investigates the combination of commercially available low-frequency (LF) Hall-effect current sensors (BW $\mathbf {\approx 1}$ MHz) with suitable high-frequency (HF) sensors to extend the BW above $\mathbf {10}$ MHz, i.e., enough to measure the HF inductor current. Based on a conventional PCB-integrated Rogowski coil, for the HF sensor, three improved pickup coil (PUC) geometries based on proposals in the literature are investigated. The LF and HF sensor signals are combined with a precision fully differential combiner circuit. Design guidelines for the HF sensors as well as the combiner circuit are presented and thereby the influence of mismatches and tolerances is examined. The performance of the proposed HF sensors is experimentally verified and compared with previous solutions based on galvanically isolated inductor voltage sensing and a current transformer. The PUCs reach a BW $\mathbf {>50}$ MHz, which is an improvement by more than a factor of $\mathbf {50}$ compared to the fastest available Hall sensor. Furthermore, it is proven that all investigated sensors are capable to accurately measure the triangular inductor current ripple in a hardware prototype of the aforementioned ac power source. In a final step, the influence of common-mode (CM) disturbances originating from fast $\mathbf {{d}v/{d}t}$ switching transients on the sensor performance is analyzed. The presented current sensors achieve a CM rejection ratio of almost $\mathbf {100}$ dB. [ABSTRACT FROM AUTHOR]

In this work, a methodology for the design and validation of a radiation monitoring (RadMON) system for electronic systems in particle accelerators is presented. The methodology expands the common radiation hardness assurance (RHA) procedure implemented at CERN, including new steps dedicated to both system-level testing, focused on a wireless device, and sensors characterization and readout validation. A case study demonstrating the validity of this methodology is proposed with the qualification of a novel battery-powered wireless RadMON system. This system not only represents the validation vehicle of the methodology but also an innovation in terms of monitoring platform due to its flexibility and improved capabilities. The application of this methodology allowed its full qualification, providing useful data in terms of resistance to radiation, lifetime, and failure rate in operation, demonstrating the validity of the testing strategy proposed in the article. [ABSTRACT FROM AUTHOR]

Virtual synchronous generator (VSG), recognized as a grid-friendly control technique, contributes to providing inertia and damping support from the grid-tied power electronic systems. However, similar to the conventional synchronous generator, the VSG is vulnerable to wideband oscillations and can even become unstable when the system is subjected to a variety of disturbances. To tackle this issue, this article proposes a magnitude-phase motion equation (MPME) for grid-forming VSG attached to a weak grid. Besides, a feedback analytical method is introduced to identify the frequency dynamic stability, judged by the sign of (dω/dt)/δω. Besides, the rate of change of frequency (RoCoF) and frequency nadir (FN) are evaluated by the two indices, i.e., dω/dt and δω. In addition, the relationship between the low-inertia-RoCoF-FN-related stability and the weak-damping-oscillation-related stability is illustrated by the feedback analysis. Moreover, in the framework of MPME, a reactive-power feedforward (RPFF) decoupling control strategy is proposed for the enhancement of stability and robustness performance of the VSG system. Finally, the proposed modeling and the RPFF decoupling control strategy are demonstrated with the experiments. [ABSTRACT FROM AUTHOR]

Deinterleaving mixtures of radar pulse sequences is the first and the most vital step for modern electronic reconnaissance systems to intercept and analyze the intentions of noncooperative radars. Currently, these systems are facing great challenges due to the emerging complexity of radar modulations. This article proposes a novel method for deinterleaving mixtures of radar pulse sequences based on the time series characteristics of each source (component pulse sequences). First, the mathematical representations are established to describe the structural characteristics of each source. Then, the deinterleaving problem is formulated as a minimization of a maximum-likelihood cost function that can be solved efficiently through a supervised neural machine translation (NMT) network, i.e., to translate each received pulse in the interleaved pulse sequence to the corresponding source label. A sequence-to-sequence NMT model is proposed to capture the structural relationships among the nonadjacent pulses originated from the same source in the mixtures and assign the corresponding label to each pulse. The proposed method does not require the exact knowledge of each component pulse sequence. The experimental results based on the time of arrival sequence of mixed pulse sequences show that the proposed method outperforms the state-of-the-art deinterleaving methods and achieves satisfactory performance under highly nonideal situations with measuring noise and lost pulse conditions. The proposed method can be directly applied to other fields involving deinterleaving problems and multivariate input conditions. [ABSTRACT FROM AUTHOR]

We report GaN-based vertical Schottky barrier diodes (SBDs) with embedded floating islands (FIs). The incorporation of FI structure can break the theoretical limit of unipolar vertical GaN devices by homogenizing the electric field distribution within the drift layer. To facilitate comprehensive understanding and structural design of FI SBDs, analytical models for both conducting state and blocking state of GaN FI SBDs are established and verified by TCAD simulation. Parametric optimization for the reverse characteristics of GaN FI SBDs is also carried out systematically. We found that the doping concentration, height of p-GaN FIs, and spacing between adjacent p-GaN FIs are closely associated with the electric field distribution and the reverse breakdown characteristics of vertical FI SBDs. An optimum Baliga’s figure of merit (FOM) of 4.98 GW/cm2 can be achieved, which features a 79.14% enhancement compared with the conventional SBD. The results can provide systematic design guidelines for GaN vertical power electronic systems toward high-voltage, high-speed, and high-power applications. [ABSTRACT FROM AUTHOR]

In this article, a fully physically transient volatile memristor utilizing Mg as an active electrode with a structure of W/MgO/Mg/W was proposed. The fully transient device exhibited remarkable threshold switching (TS) performance via Mg2+ cations migration dynamics and emulated the paired-pulse facilitation (PPF), paired-pulse depression (PPD), and transition from short-term to long-term plasticity of a biological synapse successfully. In addition, a water-assisted transfer printing (WTP) method was exploited to fabricate the fully physically transient system on biodegradable and biocompatible substrates. This study confirms that the fully transient volatile memristor owns outstanding value toward security neuromorphic computing, biodegradable, and bio-integrated electronic systems. [ABSTRACT FROM AUTHOR]

Hardware Trojans are malicious modifications in integrated circuits (ICs) with an intent to breach security and compromise the reliability of an electronic system. This article proposes a framework using self-testing, advanced imaging, and image processing with machine learning to detect hardware Trojans inserted by untrusted foundries. It includes on-chip test structures with negligible power, delay, and silicon area overheads. The core step of the framework is on-chip golden circuit design, which can provide authentic samples for image-based Trojan detection through self-testing. This core step enables a golden-chip-free Trojan detection that does not rely on an existing image data set from Trojan-free chip or image synthesizing. We have conducted an in-depth analysis of detection steps and discussed possible attacks with countermeasures to strengthen this framework. The performance evaluation on a 28-nm FPGA and a 90-nm IC validates its high accuracy and reliability for practical applications. [ABSTRACT FROM AUTHOR]

Doppler ultrasound techniques are currently employed in several industrial, consumer, and biomedical applications. They are implemented in electronic systems of different complexity, from simple, low-cost embedded boards to high-end echographs. The development, implementation, and periodic verification of such systems involve complex tests carried out through flow rigs and phantoms. Unfortunately, these hydraulic circuits are affected by several issues, such as the huge dimensions and the lack of the accurate reference for the velocity distribution developed by the fluid. In this article, we present an innovative flow emulator board (FEB). The FEB is compact and does not need moving fluids or pumps. Moreover, it produces a signal that mimics a programmable velocity profile with known characteristics. The FEB can replace the flow rigs in most of the tests where pulsed wave Doppler (PWD) methods and PWD electronics’ systems are involved. The presented experiments show that the proposed FEB synthetizes arbitrary flow velocity profiles with programmable clutter, white noise, propagation attenuation, and sample volume extension, and show how FEB is employed for testing an industrial sensor and a research echograph. [ABSTRACT FROM AUTHOR]

Fault-tolerant control (FTC) strategies have been proposed to improve the reliability of power electronic systems. However, the FTC of the three-level T-type converter based shunt active power filter (SAPF) remains limited by redundant devices. To address this problem, an FTC strategy called sequential model predictive tolerant control (SMPTC) is combined with a nonintegral lexicographic optimization (LO) algorithm for solving multiobjective optimization problems. First, the power circuit, space voltage vector diagram, harmonic extraction, and prediction models of the SAPF system are introduced. Second, based on power-switch fault analysis, an adaptive dc bus voltage regulation method is proposed, which ensures that the candidate voltage vectors are fully utilized in the fault state. Third, an LO-SMPTC strategy is proposed by designing a sequential predictive controller that considers the neutral point (NP) voltage and the tracking of the SAPF output current. Compared with the traditional model predictive control, the proposed method not only achieves NP voltage balance and excellent harmonic compensation but also eliminates the selection of weighting factors, thereby improving the control flexibility and time efficiency. Finally, the effectiveness of the LO-SMPTC on the dc bus voltage, NP voltage oscillations, grid current power quality, and pole voltage under different scenarios is demonstrated through experiments. [ABSTRACT FROM AUTHOR]

The emerging flexible multilayer foils (FMLFs)-based winding design has a great potential to promote the magnetic integration technique in power electronic systems. This article investigates the full integration of a single-phase electromagnetic interference (EMI) choke with well-designed FMLFs. By sharing a UU-type core and configuring the windings reasonably, all the common-mode (CM) inductance and capacitances and differential-mode (DM) inductances and capacitances can be integrated into the same core unit. Moreover, the proper terminal configuration of conductive layers can realize function-decoupling between CM and DM filtering elements, which contributes to simplifying the equivalent CM and DM models, then predigesting the parameters design procedure. Following the modeling and theoretical analysis, prototypes of the proposed and existing EMI chokes have been built for a single-phase 200-kHz SiC-mosfet inverter system. Through experimental measurements, performance comparisons have been presented to demonstrate the validity of this model. [ABSTRACT FROM AUTHOR]

Early fault detection in power electronic systems (PESs) to maintain reliability is one of the most important issues that has been significantly addressed in recent years. In this article, after reviewing various works of literature based on fault detection in PESs, data mining-based techniques including artificial neural network, machine learning, and deep learning algorithms are introduced. Then, the fault detection routine in PESs is expressed by introducing signal measurement sensors and how to extract the feature from them. Finally, based on studies, the performance of various data mining methods in detecting PESs faults is evaluated. The results of evaluations show that the deep learning-based techniques given the ability of feature extraction from measured signals are significantly more effective than other methods and as an ideal tool for future applications in the power electronics industry are introduced. [ABSTRACT FROM AUTHOR]

An on-die oscilloscope circuit is proposed to monitor the power noise waveforms inside IC due to the transient stress events for a more complete analysis of the effects of the transient stress events on the electronic systems. When the transient stress event occurs, the induced noise voltage waveform in the power supply is sampled and converted to digital data in real time. A trigger signal created by the event detector circuit is used to hold the digital data. The stored digital data inside the on-die oscilloscope are reconstructed back to the analog noise waveform based on the sampling process. The operation of each circuit block in the on-die oscilloscope is analyzed and validated by simulation and measurement results. The approximate bandwidth of the proposed on-die oscilloscope is extracted from simulation results. The power noise waveforms due to the transmission line pulse events and electrostatic discharge events are measured with an external oscilloscope instrument using cables and directly sampled and reconstructed by the on-die oscilloscope, and these measured and reconstructed analog noise waveforms are compared with each other. [ABSTRACT FROM AUTHOR]

Power distribution network (PDN) is essential in electronic systems to provide reliable power for load devices. Thus, modeling of PDNs in printed circuit boards and packages has been extensively studied in the past few decades. However, with the higher integration levels and operation bandwidths of modern voltage regulator module (VRM), there lacks an accurate model for transient load responses based on the widely used current-mode control topology. In this work, a topology-based behavior model, including both the power stage and control loops, is developed for the current-mode buck VRM. A novel method is also proposed to unify the modeling of the continuous and discontinuous conduction modes for transient load responses. Through the measurement-based characterization, the model parameters are optimized to match with the actual design. Furthermore, this model can be applied to both the time-domain and frequency-domain circuit simulations to predict the voltage droop and output impedance, respectively. The accuracy of the model is validated using an evaluation board containing the single-phase and multiphase VRMs. The proposed model for current-mode control VRM can be easily cascaded with other PDN components to enable a combined PDN analysis. [ABSTRACT FROM AUTHOR]

On-skin stretchable electronic devices that can acquire electrophysiological signals for controllable human-machine interactions are of considerable importance in wearable robotics applications. The straightforward, large-area fabrication of structurally stretchable electronic sensors processed by ultrafast laser ablation techniques provides great insights into low-cost wearable stretchable sensors. In this article, a patch-based large-area frame-type stretchable sensor array system that covers a large portion (∼20 cm wide) of the human arm—processed by a simple, ultrafast (<4 min), user-accessible, mask-independent laser ablation technique—is demonstrated with resolutions down to 50 μm and 100% yield. The Ecoflex_PDMS-PEIE patch—an enabling material of soft (low modulus, ∼50 kPa), reversible adhesion to the skin (∼3.3 kPa), high permeability for water loss (∼8 gm-2h-1), and high stretchability (>100%)—allows the sensor to conformally attach to the skin for long-term usage. The patch-based sensor exhibited robust electromechanical properties under significant mechanical loadings for 10 000 cycles, a promising characteristic for product commercialization. Moreover, the results suggest that the proposed method is suitable for the fabrication of diverse materials for stretchable electronic applications. We verified the application of electromyography signals with human motion determination to control the movements of the robotic hand. [ABSTRACT FROM AUTHOR]

The extended state observer (ESO) is used to estimate both the unmeasurable system states and acting lumped disturbance. Generally, high gains need to be selected in ESO to achieve fast convergence, which can make it sensitive to measurement noise. To address this limitation, a governing structure with a special combination of Kalman filter (KF) and ESO is proposed. The former serves as noise filtration while the latter is responsible for on-line reconstruction of states and disturbance. The two are connected as the system model used for the KF design contains a constantly updated estimate of the lumped disturbance obtained with the ESO. Finally, the resultant estimates are used to construct a composite disturbance rejection-based controller. To verify the new method, hardware experiments are performed on an electronic throttle system. Conducted quantitative comparison with conventional solution reveals advantages of the proposed approach in noise attenuation and control performance. [ABSTRACT FROM AUTHOR]

This article investigates the fin- and finger-number dependence of the total ionizing dose (TID) degradation in 16-nm bulk Si FinFETs at ultrahigh doses. n- and p-FinFETs designed with different numbers of fins and fingers are irradiated up to 500 Mrad(SiO2) and then annealed for 24 h at 100 °C. The TID responses of nFinFETs are insensitive to the fin number, as dominated by border and interface trap generation in shallow trench isolation (STI) and/or gate oxide. However, pFinFETs show a visible fin-number dependence with worst tolerance of transistors with the smallest number of fins. The fin number dependence may be related to a larger charge trapping in STI located at the opposite lateral sides of the first and last fins. In addition, both n- and p-FinFETs exhibit an almost TID insensitivity to the finger number. During the design of integrated circuits, the TID tolerance of electronic systems can be enhanced by preferably using transistors with a higher number of fins than fingers. [ABSTRACT FROM AUTHOR]

Recent trends in automotive electronics such as automated driving will increase the number and complexity of electronics used in safety-relevant applications. Applications in logistics or ridesharing will require a specific year of service rather than the conventional mileage usage. Reliable operations of the electronic systems must be assured at all times, regardless of the usage condition. A more dynamic and on-demand way of assuring the system availability will have to be developed. This article proposes a thermomechanical stress-based prognostics method as a potential solution. The goal is achieved by several novel advancements. On the experimental front, a key microelectronics package is developed to directly apply the prognostics and health management concept using a piezoresistive silicon-based stress sensor. Additional hardware for safe and secure data transmission and data processing is also developed, which is critically required for recording in situ and real-time data. On the data management front, proper data-driven approaches have to be identified to handle the unique dataset from the stress sensor employed in this study. The approaches effectively handle the massive amount of data that reveals the important information and automation of the prognostic process and thus to be able to detect, classify, locate, and predict the failure. The statistical techniques for diagnostics and the machine learning algorithms for health assessment and prognostics are also determined to implement the approaches in a simple, fast, but accurate way within the capacity of limited computing power. The proposed prognostics approach is implemented with actual microelectronics packages subjected to harsh accelerated testing conditions. The results corroborate the validity of the proposed prognostics approach. [ABSTRACT FROM AUTHOR]

Conventional ultrasound probes have inherent limitations in some application scenarios. Because of their fixed shapes and sizes, they can hardly pass through small orifices to examine the target closely. With the recent development of microelectromechanical systems and flexible electronic technologies, collapsible and self-assembling devices are being considered as a potential approach to address this problem. This article presents an innovative transformable ultrasonic transducer (TUT), which can transform between a one-dimensional (1-D) linear array and a 2-D planar array with the ability of switching between different functions including 2-D/3-D imaging and high-intensity focused ultrasound beamforming. The transforming process is accomplished with a specially designed flexible printed circuit board inspired by a paper-folding mechanism. The electrical and acoustic properties of the developed transducer along with the acoustic field distribution in its different forms have been characterized. The 2-D/3-D imaging performances of the TUT have been also evaluated under 1-D and 2-D configurations, respectively. In addition, the performance of a focused concave transforming mode has been also discussed. The evaluation results suggest that TUT can maintain its performance under different structures with precise transforming control. The TUT device has the potential to considerably expand the applications of industrial and clinical ultrasound. [ABSTRACT FROM AUTHOR]

This letter proposes a frequency-domain participation analysis approach to identifying the root cause of small-signal instability for electronic power systems. Differing from the participation analysis based on state-space analysis, the proposed approach is implemented based on impedance models, which is, thus, readily applicable for large-scale systems only with black-box models. The theoretical analysis is finally verified by the simulations and experiments. [ABSTRACT FROM AUTHOR]

High-voltage p-i-n diodes for space applications are sensitive to single event burnout (SEB), which may cause the failure of the entire electronic system. This article describes the SEB failure mechanism of high-voltage p-i-n diodes with field limiting rings (FLRs) termination structure, based on the electro-thermal coupled transient simulation model in the Sentaurus TCAD simulator. The simulation results show that the catastrophic failures result from the intense local heating at the edge of the main junction, because the high electric field strength at this region induces strong impact ionization of the charge carriers. The strike at the edge of the main junction shows the strongest sensitivity to SEB since the energetic particle-induced carriers are deposited exactly at the high electric field region. Then, a novel SEB hardening technique of localized carrier lifetime control at the edge of the main junction region is proposed based on the analysis on the failure mechanism. Our simulation results demonstrate that the reduction of the localized carrier lifetime can alleviate the peak electric field and reduce the local heat accumulation, thereby improving the SEB performance of high-voltage p-i-n diodes. [ABSTRACT FROM AUTHOR]

A distinctive frequency selective surface (FSS) to effectively enhance the electromagnetic shielding performance of high-speed electronic systems while preserving good mechanical ventilation is proposed in this article. The FSS consists of periodic segmented circular patterns in two-dimensional view and hollow vent holes in spatial, which exhibits a wide 2 GHz stopband at the interested frequency of 28 GHz. The new design also demonstrates stability to wave oblique incidence and polarization. The FSS shielding panel is prototyped and measured for validation. A satisfactory agreement between simulation and physical experiment is achieved. [ABSTRACT FROM AUTHOR]

Consumer electronics hardware is designed and manufactured following a global supply chain which opens doors to their security challenges. Even with the advanced methods of formal verification and coverage analysis, there is still a chance of hiding malicious hardware/software which can degrade performance, leak data, or even stop functionalities. In this work, we present security solution of Network on Chip (NoC) based Multiprocessor System-on-Chip (MPSoC) consumer electronics (CE) systems such as set-top boxes and autonomous vehicles. Most of the existing methods targeted for such systems focus on protection in Network Interfaces (NI) and other software solutions rather than routers against Hardware Trojans (HT) which can be embedded in NoC by a rogue designer. In this work, we propose a 3-tier methodology leading to “Fortified-NoC” to secure the data and resources against different kinds of threats. A Trojan cognizant routing algorithm (TCRA) is proposed which limits the HTs to a particular router that contains them. Data shuffling with Trojan detectability is also used to mislead and identify the HTs. We validated the proposed approach using various experiments. Our proposed method is capable of mitigating the Trojan attacks such as data leakage, performance degradation, denial of service and live locking of data packets at the cost of a little latency and, some extra hardware. It is able to recover more than 80% of lost packets, improve the throughput by $1.3\times $ against performance degrading Trojan attacks. [ABSTRACT FROM AUTHOR]

Quartz crystal resonators are the key component of various kinds of electronic systems because they provide the reference frequency source of the system running clocks. However, the frequency stability is often affected by the temperature. Therefore, the frequency–temperature ($f-T$) characteristic modeling has been an important research topic in the frequency control field. The classic $f-T$ modeling method omits the system dynamics and may lead to a large frequency compensation error in the case of rapid temperature changing. To deal with this issue, this article proposes a dynamic $f-T$ modeling method based on improved echo state network (ESN), called residual scaled ESN (RSESN). In the proposed method, the residual modeling framework is designed for purposes of good physical understandability and high prediction precision. This framework uses the static polynomial $f-T$ model to depict the approximated data relationship and applies the complicated network model to compensate the detailed dynamic error. To estimate the dynamic errors, one effective dynamic modeling tool, ESN, is introduced to build the dynamic compensation model for $f-T$ characteristic of quartz crystal resonators. For a better fitting performance, the ESN activation limitations are analyzed and the scaled echo states are constructed in the improved ESN model. The modeling and testing results on the real experiment data show that the proposed method can capture the dynamic information effectively and provide better frequency deviation predictions. [ABSTRACT FROM AUTHOR]

Radar emitter classification (REC) plays an increasingly significant role in the electronic reconnaissance system. Due to there are many unreliable factors in traditional feature-based methods, this article focuses on improving the accuracy and stability of REC based on multipaths of original radar signals. A novel aggregated multipath extreme gradient boosting (AMP-XGBoost) is therefore put forward. Multi-path, including multi-scale, multi-domain transformations and their concatenations, is developed to exploit more information of the original signal, which contributes to providing more distinguishable features. XGBoost is used to automatically extract the features contained in these paths and complete recognition. Finally, multiple paths are sifted and aggregated according to certain weights to obtain a higher accuracy. Experiments are carried out based on signals from 6 different intra-pulse modulation mode radars with the same radio frequency (RF) range. It is demonstrated that the proposed method has higher REC accuracy than the methods only based on a single scale or domain. In the meantime, experimental results under different low SNRs show that the proposed method has higher stability. Finally, experiments based on the measured aviation radar data proves the superiority of the proposed method. [ABSTRACT FROM AUTHOR]

We propose to suppress high-power microwave pulses (HPMPs) using nonlinear dispersion and filtering natures of spoof surface plasmon polaritons (SSPPs). Frequency components of a short HPMP are distributed in time domain due to different group velocities and partly cutoff on SSPP transmission lines (TLs), leading to peak suppression of HPMP. To illustrate the protection mechanism in real microwave engineering, an SSPP mono-pulse antenna is designed. Sum and difference beam functions of the antenna are demonstrated by both simulations and experiments. For easy comparison, a microstrip mono-pulse antenna is also fabricated. HPMP incidences from the main lobe directions of the sum beam and difference beam are considered. Compared to the microstrip antenna, obvious suppression of HPMPs is observed in the SSPP mono-pulse antenna in different cases, which verifies the better performance to prevent HPMP damages by SSPPs. The proposed technology to suppress HPMPs by using SSPPs can find wide applications in radar and communication systems in the electronic warfare environment. [ABSTRACT FROM AUTHOR]

Unlike biomimetic methods, the insect–computer hybrid is an alternative approach to developing insect-scale robots. Insect–computer hybrid is a technique that transforms a living insect into a controllable robot by embedding it with artificial devices. In this article, a beetle (Mecynorrhina torquata) was transformed into a hybrid flying system by mounting an electronic backpack and implanting electrodes on it. Wing trajectories during fictive flight climbing and flight diving were captured to investigate the natural flight-height control of beetles. Compare with the electrically induced wing trajectories via basalar, subalar, and third axillary (3Ax) muscle stimulations, we hypothesized that the basalar muscles are involved in ascending flight, whereas the 3Ax muscles function to reduce the flight-height. By reproducing the electrical stimulations on bilateral muscle pairs during free flights, we found that stimulations of the basalar muscle pair increased vertical accelerations. In contrast, the 3Ax muscle pair's stimulation decreased vertical accelerations gradually as a function of the electrical stimulation frequency. Accordingly, a proportional-derivative feedback controller was proposed to maintain the beetles' flight-height using frequency-dependent electrical pulses on the basalar and 3Ax muscles. In this article, the altitude control of a free-flying beetle was demonstrated for the first time. [ABSTRACT FROM AUTHOR]

In this article, a method for solving cable layout optimization problems in electronic systems based on ensemble learning (EL) and improved differential evolution (DE) algorithm is proposed. Using this method, we produced two cable layout schemes with the considerations of the electromagnetic compatibility performance and the total length of cables. First, several different individual machine learning (ML) models for all output variables were established. On this basis, we established EL models with better performance than previous individual ML models. Then, aiming at the optimization problem presented in this article, an improved DE algorithm was proposed. On this basis, a method for solving cable layout optimization problems in electronic systems based on EL and the improved DE algorithm was proposed. Finally, the effectiveness of the proposed method was verified by two examples of electronic system cable layout optimization with different routing modes. Each example problem was solved using four different methods. The results indicate that the method proposed here outperformed existing methods. [ABSTRACT FROM AUTHOR]