Miracle-dz/UniFAR-FTUs huggingface dataset:
QCM-Enabled SiC Three-Phase Traction Inverter

This article proposes a quadrilateral current mode (QCM) soft-switching scheme for three-phase traction inverters with multiple SiC power metal-oxide-semiconductor field-effect transistors (MOSFETs) in parallel. A phase-shift modulation scheme is applied to inductor-decoupled parallel half-bridge legs, generating a circulating current flowing through these commutation inductors. Thus, the current of each half-bridge leg is reshaped as quadrilaterals, which enables all the parallel MOSFETs to achieve zero-voltage switching (ZVS). The switching losses of the 650-V STPAK™ SiC MOSFET at different junction temperatures are characterized with double-pulse tests. Then the operation principle and characteristics of QCM are detailed. Finally, a QCM-enabled three-phase traction inverter using the STPAK SiC MOSFETs is developed and tested to verify the advantages of QCM operation in power loss reduction and efficiency improvement.
A Carried-based Space Vector Modulation Scheme for Si and SiC based Enhanced Hybrid-ANPC Converter

Recently, Silicon (Si) and Silicon-carbide (SiC) based hybrid active neutral-point-clamped (ANPC) topologies have gained significant interests owing to their high efficiency to cost ratio. Among these hybrid ANPCs, the enhanced-hybrid-ANPC (E-HANPC) minimizes the commutation issues of SiC switches and offers high efficiency. In this paper, a carrier-based space-vector-modulation (SVM) scheme is proposed for EHANPC topology. The proposed SVM scheme reduces converter switching losses using SiC MOSFETs, while conduction losses are reduced by operating Si IGBTs in parallel conduction paths. Moreover, with the proposed SVM scheme, Si IGBTs are switched at either zero or reduced current value. In this way, the overall converter losses are reduced with the proposed SVM scheme. This paper presents detailed derivation of proposed scheme. Moreover, converter loss analysis and selection criterion for Si IGBTs to achieve maximum loss reduction are presented. The performance of proposed scheme is validated with the simulation and experimental results using reduced-scale three-phase experimental prototype.
Lane Change Decision Algorithm based on Risk Prediction and Fuzzy Logic Method

One major objective of the autonomous driving is to act similarly to a real driver for two main reasons: to be comprehensible by the surrounding drivers, and to be accepted by the passengers. In this work, a decision algorithm for lane changing in highways and arterial road is elaborated. The first step consists of a risk assessment based on predicted trajectories to determine the optimal moment to start the maneuver. Based on the level of risk and a coefficient called “Gain” that measures the driver’s interest in changing lane, a fuzzy logic model decides if the maneuver should be performed or not.
Implementation of a neural network to adaptively identify and control VSI fed induction motor stator currents

This paper presents a prototype hardware implementation of a continually online trained artificial neural network to adaptively identify the electrical dynamics of an induction machine and control its stator currents from a pulse width modulated voltage source inverter. A single transputer based hardware platform is described and the effects of computational speed limitations on the controller bandwidth are discussed. Captured results are compared with simulation results to practically verify the success of the adaptive neural network identification and control scheme. <<ETX>>
The Loss of the Space Shuttle Columbia: Portaging Leadership Lessons with a Critical Thinking Model

Abstract: Business schools have long valued case studies as a tool for both broadening a student's perspective, and provoking them to deeper consideration of complex situations. The challenge with case studies is assuring the portability of the lessons; we don't expect students to see situations imitating those they've studied, hence the goal must instead be habits of mind and principles of action that the student can portage to the circumstances of their professional lives. This article evaluates the suitability of Richard Paul's Critical Thinking model as a template for evaluating engineering enterprise thinking habits and organizational behavior, using the Columbia Accident Investigation Board (CAIB) report as a case study. With minor refinement, Paul's model provides a powerful vocabulary for complicated case study analysis; familiarity with the model provides participants with both a mechanism for analysis and a means for portaging lessons to other professional situations and organizations.
Electric Intelligent Safety Monitoring Identification Based on YOLOv4

With the continuous development of smart grid, the intelligent and automation level of power grid production safety supervision management mode needs to be improved. In order to solve this problem, this paper proposes a method based on YOLOv4 to identify the unsafe behaviors related to construction, including wearing safety helmet, working clothes and insulating gloves. In this paper, based on image recognition technology, the behavior analysis model is established to automatically identify whether the operator's behavior meets the safety requirements. The mAP of the final algorithm is 91.38%. In this paper, the judgment basis and logic of safety supervision alarm logic for multi construction scenarios are constructed, which provides a new idea for the application of deep learning algorithm in power intelligent safety supervision.
Hall-Effect Sensors as Multipurpose Devices to Control, Monitor and Diagnose AC Permanent Magnet Synchronous Machines

The increasing use of permanent magnet synchronous machines is motivating the research on lower cost and higher reliability techniques for control, diagnostics and condition monitoring. Control of PMSMs typically involves current and position sensors while diagnostics tasks usually rely on vibration, flux measurements, current monitoring etc. Hall-effect sensors have shown to be a low cost, robust and reliable option for position/speed feedback (to control the machine), online monitoring and detection of failures through the leakage flux measurement using simple processing algorithms. This paper summarizes the available techniques for motion control, monitoring and diagnosis of permanent magnet synchronous machines using Hall-effect sensors and proposes a processing method to allow simultaneous operation of all these techniques. The output of the proposed system are estimations of the rotor position, electromagnetic torque, permanent magnet magnetization state, permanent magnet temperature and degree of eccentricity.
On-State Voltage Measurement of High-Side Power Transistors in Three-Phase Four-Leg Inverter for In-Situ Prognostics

This paper presents the challenges of implementing in-situ prognostics to practical power converters and proposes a new on-state voltage (VDSON) monitoring circuit for the high-side power transistors. The proposed approach references the drain of the high-side transistors for their VDSON measurement. This circuit allows VDSON measurement of not only multiple high-side transistors but also multiple low-side transistors at the same time. The measured VDSON is used to calculate on-state resistance (RDSON) in real-time using the drain-current measured using an off-the-shelf hall effect current sensor. The proposed circuit is used in a 75 kW 1000 VDC three-phase DC-AC inverter for in-situ prognostics. Validations of the proposed VDSON measurement circuit and RDSON monitoring are presented using theoretical circuit analysis and experimental results. The measured RDSON is found to be in the datasheet specified range.
Four Motion Branches of an Origami Based Eight Bar Spatial Mechanism

An eight bar spatial mechanism inspired from an origami paper fold by considering the carton panels as links and creases as revolute joints is proposed. The constraint deposition and motion characteristics analyses of the eight bar spatial mechanism show that the mechanism implements one screw motion and one pure translation. The configuration space of the mechanism comprises four subspaces. Through adding different geometrical constraints to the eight bar spatial mechanism, different motions of the end-effector are limited leading to three 2-DOF and one 1-DOF motion branches. Additional geometrical constrained conditions in four motion branches with aimed motions of double translations, single translation and two single screw motions are revealed. In the first two motion branches, the eight bar spatial mechanism remains the constant relative orientations of joint-axes. However, the joint-axes of the eight bar spatial mechanism change their orientations in the last two motion branches. Kinematic analyses are discussed in four motion branches, respectively.Copyright © 2013 by ASME
Development of an Automatic Traffic Conflict Detection System Based on Image Tracking Technology

Increasing reliance on surveillance has emphasized the need for better vehicle detection, such as with wide-area detectors. Traffic information from vehicle trajectories can be especially useful because it measures spatial information rather than single-point information. Additional information from vehicle trajectories could lead to improved incident detection, both by identifying stopped vehicles within the camera's field of view and by tracking detailed vehicle movement trajectories. In this research, a vehicle image processing system was developed by using a vehicle tracking algorithm, and a traffic conflict technology was applied to the tracking system. To overcome the limitations of the existing traffic conflict technology, this study developed a traffic conflict technology that considers the severity of different types of conflict. To apply this method, video images were collected from intersections at Jungja and Naejung in Sungnam City, South Korea. The image processing approach adopted in this research was based on the use of a single camera installed at the corner of a street to detect vehicles approaching an intersection from all directions, and they were analyzed with the traffic information extracted from the image tracking system. To verify the tracking system, three categories were tested: traffic volume and speed accuracy, vehicle trajectory tracking, and traffic conflict.
3D Thermal Network Modeling for Axial-Flux Permanent Magnet Machines with Experimental Validation

A thermal resistance network model is presented for an axial flux permanent magnet (AFPM) motor. The model leverages similarity, typical to AFPMs, allowing use of a half slot, half tooth model, suitable for both single rotor, single stator (SRSS) and single rotor, dual stator (SRDS) AFPM machines. The presented approach leverages 3-dimensional (3D) thermal resistance networking, incorporating anisotropic material properties as well as analytical air gap and cold plate convection heat transfer coefficients for prediction of steady state thermal performance. This method offers significantly reduced computation time, when compared with conventional 3D finite element (FE) methods and eliminates the need for timely computation fluid dynamic (CFD) analysis. The proposed thermal network is configured such that the end user is able to ascertain thermal gradients and hot spots within the motor without computationally demanding 3D FEA and CFD analysis. Bulk thermal and temperature gradient predictions are first validated with a SRSS AFPM motor 3D FE model and lastly correlated with SRDS AFPM motor thermal test data, validating the presented modeling technique.
A phase noise reduction method in microwave oscillator using a high‐Q transmission line loaded with active SIW resonator

In this letter, a transmission line (TL) loaded with active circular substrate integrated waveguide (SIW) resonator is presented and used in microwave oscillator to reduce phase noise. By compensating the resonance loss in SIW cavity using coupling negative resistance method in active resonator, the TL loaded with active SIW resonator exhibits a sharp reflective property at the fundamental mode resonance frequency which is suitable for series feedback oscillator. The simulated loaded Q‐factor of the proposed TL achieves 379. To validate this method, X‐band oscillators using TL loaded with active and passive SIW resonator are designed and implemented. The measured results show that the oscillator base on active SIW resonator exhibits a low phase noise of −128.75 dBc/Hz at 1 MHz offset frequency from 11.01 GHz carrier, which is 9 dB better than the oscillator based on passive SIW resonator. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:221–225, 2016
Neural Networks as Alternative to Traditional Factor Approach of Annual Average Daily Traffic Estimation from Traffic Counts

Presented in this paper is a comparison of the neural network approach and the traditional factor approach for estimating annual average daily traffic (AADT) from 48-h sample traffic counts. Minnesota’s automatic traffic recorder (ATR) sites are investigated. The traditional AADT estimation approach involves application of volume adjustment factors to sample counts. The neural network model used in this study is based on a multilayered, feed-forward, and back-propagation design for supervised learning. The results of AADT estimation from a single shortperiod traffic count indicate that as compared with the neural network approach, the estimation errors for the factor approach can be lower under a scenario in which ATR sites are grouped appropriately and the sample sites are correctly assigned to various ATR groups. Unfortunately, the current recommended practice offers little guidance on how to achieve the assignment accuracy that may be necessary for obtaining reliable AADT estimates from sample counts. The advantage of the neural network approach is that classification of ATR sites and sample site assignments are not required. The neural network approach can be particularly suitable for estimating AADT from two or more shortperiod traffic counts taken at different times during the counting season.
A Coordinated Droop Controls and Power Management Scheme for Hybrid Energy Storage Systems in DC Microgrids

This paper proposes a coordinated droop controls for multiple hybrid energy storage systems (HESSs) including the batteries and supercapacitors (SCs) to achieve the slow- and fast-dynamic power-sharing as well as dc bus voltage restoration in a dc microgrid. A $V$-dP/dt droop scheme is proposed to control the output power of battery converters with a slow dynamic response. The traditional power droop is employed to regulate the SC converters to give a fast response. The dc bus voltage is maintained in a safe range by the SC converter control so that no voltage recovery loop is required. Hence, the order of the overall control system and the complexity of parameter design can be reduced. In addition, a power management scheme (PMS) is proposed to ensure the system power balance and protect the batteries from over-charge/over-discharge under different operating modes. A state of charge (SoC) balancing method is proposed to solve the issue of SoC imbalance among batteries with different capacities. Then, the SoC restoration of the SCs is considered. The output impedance characteristics and control system design are elaborated in detail. The processor in the loop (PIL) simulation results verified the effectiveness and feasibility of the proposed control method.
Comparison Between Two Brain Computer Interface Systems Aiming to Control a Mobile Robot

A Brain Computer Interface (BCI) is a type of communication device between the brain and a computer system without the need of normal muscle activation pathways. This technology has offered patients with locked-in syndrome a way to communicate with the outside world. The purpose of this paper is to present the results of a comparison between two state of the art pieces of BCI equipment. One employs the active dry electrodes on a non-portable BCI system, and the second is the g.Nautilus wearable BCI device with active wet electrodes. The applications in question deal with the control of a mobile robotic platform using the Steady State Visually Evoked Potential and the Motor Imagery methods. The comparison takes into account delays in controlling the external device, the performances to collect the proper EEG signals, their treatment and extraction of the required info for the proposed control, time to prepare the required set-up etc.
A MHz LLC Converter Based Single-Stage Soft-Switching Isolated Inverter with Hybrid Modulation Method

The inverter that requires isolation typically consists of an isolated dc-dc and a pulse-width-modulated dc-ac stages. However, the component counts, control complexity, efficiency and power density tend to be suffered with such a two-stage configuration. In this paper, a single-stage soft-switching isolated inverter based on MHz LLC converter is introduced with a novel hybrid modulation method, which operates under full-bridge and half-bridge variable frequency conditions for high- and low-line outputs, respectively. A rectified sine wave can be generated at the output of LLC converter and isolated through a high-frequency transformer for additional voltage gains. A lossless line frequency unfolder circuit is added afterwards to convert the rectified sine wave to ac sine output. The optimization method for the resonant tank is also proposed to achieve even lower voltage gains at high frequency to improve the output ac waveform quality. Compared to the traditional two-stage method, this single-stage solution makes the circuit simpler, and the bulky dc bus capacitor can be saved. To verify the circuit design and the proposed hybrid modulation method, a GaN based 380 Vdc – 600 Vac, 1.2 kW prototype is built and tested. Under the full load condition, the measured total harmonic distortion of output voltage is 2.67% with 98.30% efficiency for the overall inverter.
An Energy Recovery Scheme for RCD Snubber in the Series Configuration of IGBTs

This paper presents an energy recovery scheme for traditional Resistor-Capacitor-Diode (RCD) snubber in the series-connected configuration of IGBTs. In the series configuration of IGBTs, an RCD snubber is used in parallel to each IGBT to provide a safe operating condition for the IGBTs. In the proposed scheme, by using interconnection diodes, the capacitors of the snubbers are parallelized in the on-state of the IGBTs. Thus, the stored energies in the snubber capacitors are lumped together and transferred to the DC link by using a transformer and a resonant circuit. By using the proposed method, the capacitor of the snubber can have a higher value. A higher value of the snubber capacitance improves voltage sharing of the IGBTs and reduces the turn-off switching power losses of the IGBTs. The proposed scheme is simulated for a case study using PSPICE software and tested through an experimental setup. Simulation and experimental results imply the proper performance of the proposed scheme.
Analytical Modeling and Design Optimization of a Vernier Permanent Magnet Motor

In this paper, we present the analysis and design optimization of a Vernier permanent magnet (VPM) motor for direct-drive applications. A subdomain-based analytical model is developed for fast calculation of the electromagnetic performances, including air-gap flux, torque ripple, and power factor. Built on the analytical model, we investigate the trade-off between torque generation and power factor of the VPM motor, and conduct multi-objective optimization for key design parameters of the VPM motor. Flux density in different regions of the stator core is calculated using the analytical model, based on which a constraint is set in the objective functions to take the saturation effect into account. The design optimization process is implemented for a multi-objective optimization of the VPM motor. The optimized machine achieves over $1.8\times$ torque output compared with a commercially-available surface-mount permanent magnet direct-drive motor with the exact inner and outer dimensions at the same operating speed.
Influence of DC/DC Stage on the Design of the Output Filter of the Inverter Stage in Two-Stage Grid-Connected PV Systems

One-stage and two-stage grid connected PV systems are compared in terms of compactness for both, 1000-V and 1500-V PV string voltage levels. Design space of the inverter’s output filter is investigated for case when dc bus voltage is very well controlled to its minimum value and when it varies in the full operating range. Full multivariable optimization is conducted for the analyzed design spaces in order to investigate possible compensation of the increase of the total system volume caused by the addition of a dc/dc stage by achieving more compact inverter stage for better controlled dc bus voltage. It is concluded that for the same efficiency, filter designs with lower dc bus voltage can occupy $\approx$ 50% less volume compared to the case when dc bus varies in the full operating range. Hybrid, multilevel, partial power processing topologies that employ new classes of 650-V and 900-V WBG devices, that are already reported in the literature and that occupy $\approx$ 0.8 -0.9dm 3 for the design rated for 1500-V PV system and 20kW of the output power are very good candidates for a dc/dc stage that can control dc bus voltage at the input of the inverter stage and that can improve significantly compactness of the inverter stage and of the whole system. All the analysis and estimations are justified by comprehensive simulations of the 1500-V grid-connected PV inverter in PSIM package.
Dynamic response of HTS composite tapes to pulsed currents

Dynamic voltage–current characteristics of an HTS Ag/BiSCCO composite tape are studied both experimentally and theoretically. The tape is subjected to pulsed currents with different shapes and magnitudes and voltage traces are measured using the four-point method with different locations of potential taps on the sample surface. Clockwise and anticlockwise hysteresis loops are obtained for the same sample depending on the location of the potential taps. The dynamic characteristics deviate substantially from the DC characteristic, especially in the range of low voltages where a criterion for the critical current value is usually chosen (1–10 µV cm−1). The critical current determined from dynamic characteristics and its change with the pulse magnitude depend on the location of the potential taps and on the curve branch chosen for the critical current determination (ascending or descending). The theoretical analysis is based on a model of the magnetic flux diffusion into a composite tape for a superconductor described by the flux creep characteristic. Numerical simulation based on this model gives results in good agreement with the experimental ones and explains the observed peculiarities of the dynamic characteristics of HTS composite tapes. The difference between the magnetic diffusion into a tape and a slab is discussed.