Voltage Detection Research Articles

Quench protection of the BabyIAXO magnet

BabyIAXO, a 20 m-long twin-bore helioscope aiming for search of axion like particles, is currently in the engineering design phase and its construction is to be completed within the next 4 years. In addition to X-ray detectors and focusing optics, the system is equipped with a 50 MJ magnet with a common coil layout, containing two 10 m-long NbTi flat racetrack coils cooled by a group of cryocoolers. It has to operate at 10 kA, preferably in persistent mode with disconnected power supply, allowing to simplify the sun-tracking rotation system of BabyIAXO. A direct current mode is possible as well. Hence, quench protection is a high priority. Here, we present the electrical circuit of the BabyIAXO magnet and its protection layout when operated in persistent mode. The quench process is calculated using a 3-D thermo-electrical model of the coil windings, also accounting for the presence of the coil casing and the quench-back effect. Impact of the operating current, conductor properties, voltage detection threshold and location of hot-spot on the peak temperature is discussed. Quench protection aspects of the HTS busbars and persistent mode switch are also addressed.

Design of threshold voltage insensitive pixel driver circuitry using a-IGZO TFT for AMOLED displays

This work proposes a novel amorphous-indium-gallium-zinc-oxide thin film transistor (a-IGZO TFT) based pixel driver circuitry to compensate for threshold voltage variations of TFTs and OLED current degradations for AMOLED (Active Matrix Organic Light-Emitting Diodes) displays. The proposed circuit uses a three-phase clocking scheme i.e. threshold voltage detection phase, data input phase and emission phase for compensating threshold voltage variations. The circuit has been simulated and verified with cadence spectre using a-IGZO TFT and OLED SPICE models. The proposed circuit is able to maintain the OLED current with a maximum error of 0.68% when the threshold voltage is varied from −3.5 ​V to 3.5 ​V.

Short-circuit protection method for medium-voltage SiC MOSFET based on gate–source voltage detection

During the short-circuit fault of a two-level bridge converter based on silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs), the SiC MOSFETs may fail within a few microseconds without short-circuit protection. The short-circuit protection of SiC MOSFETs is an essential feature for improving the reliability of converters. This study proposes an improved short-circuit protection method for medium-voltage SiC MOSFETs subjected to shoot-through conditions. In the protection method, the gate–source voltage of the SiC MOSFETs in a half bridge is detected to determine whether a shoot-through short circuit occurs or not. A desaturation protection circuit based on VDS measurement for a short circuit is also designed for overcurrent. The protection circuit’s validity is verified by the experimental results. Compared with conventional commercial driver integrated circuits, the proposed method can detect and turn off SiC MOSFETs in 0.2 μs under the shoot-through condition. Desaturation protection can be completed in 0.5 μs when overcurrent occurs.

Increasing deposition height stability in robotic GTA additive manufacturing based on arc voltage sensing and control

Abstract Robotic gas tungsten arc (GTA)-based additive manufacturing (AM) is a promising technique to produce high-quality and large-scale metal parts with low cost. Despite this fact, the key issue of ensuring deposition height stability has not been fully solved. In this study, an arc voltage sensing and control approach with little delay is proposed to increase the forming height stability in GTA-based AM. The deposition height stability is indirectly characterized by arc voltage signals sampled using a designed arc voltage detection system. A novel de-noising method, combining the anti-impulse interference moving average with the wavelet packet transform, is proposed to filter out interferences in the original arc voltage. A Fuzzy-PID controller is developed to control the arc voltage by adjusting the wire feed speed on next deposition layer. Constant parameter and closed-loop control experiments are compared via fabricating thin-walled parts. The more stable arc voltage and more excellent forming appearance in the closed-loop control test indicate that applying the arc voltage sensing and control system can greatly improve the forming height stability in robotic GTA-based AM.

A New Single-Phase Direct Frequency Controller Having Reduced Switching Count without Zero-Crossing Detector for Induction Heating System

Induction heating (IH) is an environmentally friendly solution for heating and melting processes. The required high-frequency magnetic field is accomplished through frequency controllers. Direct frequency controllers (DFC) are preferred to dual converters as they have low conversion losses, compact size, and simple circuit arrangement due to low component count. Numerous frequency controllers with complex switching algorithms are employed in the induction heating process. They have a complicated circuit arrangement, and complex control as their switching sequences have to synchronize with source voltage that requires the zero-crossing detection of the input voltage. They also have a shoot-through problem and poor power quality. Therefore, this research proposes a novel frequency controller with a low count of six controlled switching devices without a zero-crossing detector (ZCD) having a simple control arrangement. The required switching signals are simply generated by using any pulse-width-modulated (PWM) generator. The performance of the proposed topology is verified through simulation results obtained using the MATLAB/Simulink environment and experimental setup.

Hardware Design of Non-contact Voltage Detector Based on STM32 Microcontroller

In view of the time-consuming and labor-intensive problems of traditional contact electroscopes, this paper designs a hardware system of non-contact voltage detector based on STM32 single-chip microcomputer. The hardware design mainly includes signal amplification and conditioning circuit and power module, Wireless transceiver module, display and alarm module, etc. In order to reduce the distortion of electric field caused by human during measurement, a wireless transceiver module device is adopted, which has a simple structure and can meet the engineering requirements of the non-contact power inspection of the transmission line.

MULTIPLE FAULT ANALYSIS USING A FUZZY LOGIC TECHNIQUE FOR AN INVERTER CONTROL DRIVE

This study evaluates electrical faults on an inverter control drive using simulations in MATLAB Simulink and recommends a fuzzy logic technique for analyzing electrical faults of such drives. Fault analysis of a drive is based on voltage, speed, current, and torque. This article presents soft computing methods for voltage fluctuations and fault detection in an inverter switch to an inverter control drive with the support of a MATLAB Simulink model. Accordingly, failure analysis techniques based on fuzzy logic are explained. The fuzzy system allows altered voltage and open-switch fault detection. Soft computing techniques offer excellent analysis of a faulty structure, even if precise models are not available. This study presents a fuzzy logic-based fault diagnosis scheme for detecting and identifying faults. The simulation outcomes reveal excellent performance of the method, proving its applicability for fault detection in squirrel-cage induction motors. All simulated results, voltage fluctuations, torques, currents, ripples, and harmonics in healthy and defective situations are analyzed.

Multi-source partial discharge detection and rapid localization of switchgear based on comprehensive diagnosis method

Partial discharge detection is an effective method to find potential insulation defects in switchgear. At present, the switchgear is mainly composed of busbars, circuit breakers, grounding knives, cables and other components, which leads to multiple faults and simultaneous discharges in the partial discharge detection process of the switchgear. In order to realize the partial discharge detection and rapid location of the switchgear, based on the introduction of the detection methods and location principles of ultrasonic, transient ground voltage and UHF partial discharge, this paper proposes to use ultrasonic, transient ground voltage and UHF detection technology to diagnose and analyse the multi-source partial discharge of the switchgear and realize the detection of partial discharge; the multi-source partial discharge of the switchgear is realized by the rapid localization method combining the UHF time difference method and the flat surface method. Through partial discharge detection and localization analysis of a 35kV switchgear, the feasibility of multi-source partial discharge diagnosis and rapid localization method is verified, which provides a basis for on-site inspection personnel to realize multi-source partial discharge detection and localization of switchgear.

Penentuan Nilai Faktor Mesin Pesawat Sinar-X Radiografi Digital Merek Shimadzu di RSUD Dr. Kanujoso Djatiwibowo Balikpapan

The research on the determining machine factor (k) of Shimadzu digital radiograph X-ray machine have been done at the RSUD Dr. Kanujoso Djatiwibowo Balikpapan. Machine factor should be required in the calculation of radiation exposure which produced by the X-ray machine. Measurement data that have been used as independent variables were current-time, focus distance to the detector and tube voltage variations of 80 kV to 100 kV, while the dependent variable was the S value. Determination of the k value was conducted by weighted linear regression between V2 and using the results of research by Seibert and Morin (2011) for the condition of calibrated X-ray machine. Thus, the reseach has obtained the machine factor of the Shimadzu digital radiograph X-ray machine at the RSUD Dr. Kanujoso Djatiwibowo Balikpapan.

TFET-Based Voltage Detector: Proposal and Investigation

In this paper, a tunnel field-effect transistor (TFET)-based voltage detector is proposed and its electrical characteristics are investigated using technology computer-aided design (TCAD) simulation. The operating principle of the proposed voltage detector is explained and possible applications in electrical overstress (EOS) and electrostatic discharge (ESD) protection are explored. Moreover, the impact of the key parameters on device performance is also discussed. The simulation results show that the proposed TFET-based voltage detector has a low leakage current and high detection sensitivity under EOS events compared to traditional diode-based detectors. With an additional nMOSFET capacitor, the proposed circuit can also be used for ESD protection.

Предпробойное состояние и его диагностика в многослойных структурах 0.55Pb-Mg-=SUB=-1/3-=/SUB=-Nb-=SUB=-2/3-=/SUB=-O-=SUB=-3-=/SUB=--0.45PbSc-=SUB=-1/2-=/SUB=- Nb-=SUB=-1/2-=/SUB=-O-=SUB=-3-=/SUB=-

Detection of breakdown voltage and diagnostics of the pre-breakdown state of a material is a topical task of studying the characteristics of dielectric materials and structures on their base under applied external electric field. A new efficient method for diagnosing the pre-breakdown state of multilayer structures (MLC) based on the 0.55PbMg1/3Nb2/3O3-0.45PbSc1/2Nb1/2O3 (PMN-PSN) ferroelectric relaxor is considered. The method is based on the analysis of the dynamics of the MLC surface temperature changes upon application of an external electric field. A set of MLC samples was tested under the action of an electric field E = 10 - 120 kV/cm at temperatures from room temperature to 80 ℃. The critical electric field value characterizing the pre-breakdown state and, consequently, limiting the upper level of operating voltages for electrocaloric applications, was determined for PMN-PSN multilayer structures.

Design of IoT-based Radiation Monitor Area for Nuclear and Radiological Emergency Preparedness System in Yogyakarta Nuclear Area

Yogyakarta Nuclear Area (YNA) is one of BATAN’s nuclear facility that has many nuclear facilities such as nuclear reactor, accelerator, irradiator, and waste management system. Due to nuclear accident is potentially occur, YNA has nuclear emergency response program and there is a preparedness system to support this program. Radiation monitoring system is one of utilization to acquire and record nuclear radiation exposure in the facility and its environment. An Internet of Thing based radiation area monitor was developed to improve the system not only to acquire the radiation exposure, but also to distribute the acquired data to the cloud server through the internet network. The distributed radiation data can be utilized to analyze nuclear emergence potential in the nuclear emergency response and preparedness system. The area monitor system was designed as sensor network that consists of Geiger Muller detector and high voltage power supply, signal conditioning system, and Arduino as counter and data processor. Data is acquired by a detector and it is transmitted to the server through wireless network using the node MCU communication module. The receiver station system was developed to acquire data from database server to display the radiation exposure in the environment and to identify radiological emergency status. Based on the chi square test stability method, the developed device has good stability which the probability of x2 was obtained 0.75. The validation testing also was done using Sr-90 and x-ray spectrometer as radiation source, and the developed device has been compared using a standard survey-meter. The mean square error of this validation testing was 0.37 and 0.24 respectively for Sr-90 at two difference source distance, while for x-ray spectrometer source the mean square error value was 2.48. For further development, the system will be combined with a smart meteorological system to build the integrated data acquisition system for Nuclear and Radiological Emergency Preparedness System in Yogyakarta Nuclear Area.

Power Stability Control Strategy of the WPT System Based on Load Detection

The output power fluctuates when offset occurs between the receiving coil and the transmitting coil or load equivalent impedance changes in a wireless power transfer system (WPT). These two conditions will affect the safety of the system and the life of the battery load. Therefore, effective control methods are needed to ensure the stability of the load power. This paper analyzes the WPT system with LCC/S compensation topology and the secondary side containing DC/DC circuit. The relationship between mutual inductance and load voltage and current, mutual inductance and the system transmission efficiency, DC/DC circuit duty ratio and load voltage and current are deduced. The output power stability control strategy through load voltage and load current detection and control of DC/DC circuit is proposed. Finally, the WPT system with 1 kW output power is built through simulation and experiment, which verifies the effectiveness and correctness of theoretical analysis and control strategy in this paper.

Describing Broadband Terahertz Response of Graphene FET Detectors by a Classical Model

Direct power detectors based on field-effect transistors are becoming widely used for terahertz applications. However, accurate characterization at terahertz frequencies of such detectors is a challenging task. The high-frequency response is dominated by parasitic coupling and loss associated with contacts and overall layout of the component. Moreover, the performance of such detectors is complicated to predict since many different physical models are used to explain the high sensitivity at terahertz frequencies. This makes it hard to draw important conclusions about the underlying device physics for these detectors. For the first time, we demonstrate accurate and comprehensive characterization of graphene field-effect transistors from1 GHz to 1.1 THz, simultaneously accessing the bias dependence, the scattering parameters, and the detector voltage responsivity. Within a frequency range of more than1 THz, and over a wide bias range, we have shown that the voltage responsivity can be accurately described using a combination of a small-signal equivalent circuit model, and the second-order series expansion terms of the nonlinear dc I-V characteristics. Without bias, the measured low-frequency responsivity was 0.3 kV/W with the input signal applied to the gate, and 2 kV/W with the input signal applied to the drain. The corresponding cutoff frequencies for the two cases were 140 and 50 GHz, respectively. With a300-GHz signal applied to the gate, a voltage responsivity of 1.8 kV/W was achieved at a drain-source current of 0.2 mA. The minimum noise equivalent power was below 30 pW/ √Hz in cold mode. Our results show that detection of terahertz signals in graphene field-effect transistors can be described over a wide frequency range by the nonlinear carrier transport characteristics obtained at static electrical fields. This finding is important for explaining the mechanism of detection and for further development of terahertz detectors.

Development of Optical Fiber Sensor Performance as a Tool to Determine Cholesterol Concentration

The purpose of this study was to determine cholesterol concentration by developing the performance of optical sensors. The use of this optical sensor is equipped with an optical fiber bundle to guide the wave in the hope of not reducing the intensity of the wave source. This sensor is simpler and inexpensive to use to determine the concentration of a material. The research method for determining cholesterol levels can be determined through the character of the laser beam to the material through a fiber optic sensor. The optical fiber sensor method is simpler and cheaper to use to determine the concentration of a material. Based on this description, research on fiber optic sensors will be developed as an instrument model to determine cholesterol concentration using a fiber optic bundle type sensor. The method used is the modulation of laser beam intensity. A beam of light that enters the optical fiber of the receiver and is processed by an optical detector into an electrical signal that will be displayed on the computer. The experimental results will obtain a linear relationship between the sensor output peak voltage as a function of variations in cholesterol concentration and parameters and sensor performance will be measured including sensitivity and linearity. The results showed that maximum voltage detection showed a linear decrease with increasing concentration with a sensitivity of 0.15 mV/ppm and a linearity of more than 97%. high sensitivity, simplicity of design, and low cost of promoting the developed sensor results in good performance detecting cholesterol concentration.

Optimisation electric field inverse solving algorithm for non‐destructive detection of voltage on transmission lines

Electromagnetic field inverse calculation plays a crucial role in solving the problem arising from the design and non-destructive testing of electromagnetic devices in engineering. In this study, an optimisation algorithm for electric field inverse calculation is proposed, which enables non-destructive detection of voltage on overhead transmission lines, enhances the robustness of the algorithm and improves the accuracy of calculation. Firstly, 2D and 3D calculation models of electric field are established. A multimedium calculation model with the operating environment of transmission lines considered is proposed. Based on the multimedium calculation method, the calculation environment is categorised into soil, vegetation, geology, and other media, and the correctness of the optimisation method is verified by the finite-element method-based model. Secondly, in order to eliminate the measurement noise and electric field distortion to the electric field measurement data, a modified model based on Kalman filter is constructed. Both multimedium calculation method and Kalman filter are applied to the inverse calculation of electric field as an optimisation electric field inverse solving algorithm. Finally, the inverse optimisation method is applied to 220 kV transmission lines and practical 500 kV ultra-high voltage transmission lines, respectively, to improve the accuracy and robustness of calculation.

Neighbor-A-Posteriori Information Assisted Cell-State Adaptive Detector for NAND Flash Memory

Cell-to-Cell interferences (CCIs), which arise from adjacent cells through parasitic coupling-capacitance, severely degrade the performance of threshold voltage detection. Pre-processing and post-processing methods have been proposed to mitigate the effect of CCIs on threshold voltage variation. The performance of the aforementioned methods heavily depends on the accuracy of the threshold voltages adjacent to the victim cells. However, to obtain high accuracy, these methods requires multi-sensing operations, thus significantly resulting in high detection latency. In this letter, a novel non-uniform detection scheme based on the threshold voltage of cell states, which is referred to as the cell-state adaptive detection (CSAD), is proposed to adapt the shifts of the threshold voltages. Then, the neighbor-a-posteriori information is exploited to mitigate the overcompensation phenomenon and further improve the performance of the CSAD under the block read mode scenario. Simulation results show that the proposed CSAD scheme and its improved version not only achieve better bit-error-rate performance but also keep lower detection latency compared with the existing detection schemes.

A 2.8-MHz 96.1%-Peak-Efficiency 1.4-μs-Settling-Time Fully Soft-Switched LED Driver With 0.08–1 Dimming Range

Present day LED drivers demand both high power efficiency and wide dimming range. However, these two parameters are often a tradeoff, where a wide dimming range requires a high switching frequency, hence the ensuing switching losses. In this paper, we present an LED driver that features both high power efficiency and wide dimming range by means of fully soft switching that substantially eliminates the switching losses, i.e., the switching losses are negligible. We achieve the said fully soft switching by our proposed hysteretic soft-switching controller (HSSC) and the proposed circuits—voltage detector, current sensor, and level shifter. The HSSC enables the fully soft switching, including zero-voltage switching and zero-current switching, by means of turning on / off power switches when their voltage/current is zero. The proposed voltage detector and current sensor, featuring low power, monitor the voltage and current of the power switches. The proposed level shifter, featuring ultra-fast speed, serves to quickly transmit the monitored signal from the said voltage detector and current sensor to the HSSC. The prototype LED driver, realized in a 130-nm BCDLite process, features 6–18 V input voltage range, output current of 0.5–1.3 A, drives 1–3 series-connected LEDs, 12-W maximum output power, 2.8-MHz maximum switching frequency, 96.1% peak power efficiency, 1.4-μs settling time, and 0.08–1 dimming range at 20-kHz dimming frequency. When benchmarked against state-of-the-art LED drivers, our design simultaneously features the widest dimming range, shortest settling time, and requires the smallest inductor. The measurements and benchmark depict the decoupling of the said tradeoff.

Research on APF Improved Control Strategy Under Three-phase Voltage Distortion

At present, the most commonly used harmonic current detection algorithms are the p-q algorithm and the ip-iq algorithm based on the instantaneous reactive power theory. The premise of using the above algorithms is that the three-phase voltage is the ideal sinusoidal voltage. However, harmonic pollution distorts the voltage of the power grid to different degrees, which will affect the detection accuracy and compensation effect of APF. This paper presents a current detection algorithm based on positive sequence fundamental wave extractor, which can avoid the detection of positive sequence fundamental wave voltage of power grid, and can effectively avoid the shortcomings of p-q algorithm and ip-iq algorithm without using PLL, complex coordinate transformation and low-pass filter. In the current control algorithm, according to the characteristic that the gain of the generalized integrator is infinite when resonance occurs, the sinusoidal and cosine instructions can be tracked without static difference, this paper which is based on the generalized integrator adaptively adjusts the coefficients of the generalized integrator to improve the robustness of the current controller. Finally, the simulation model is established by MATLAB, and the simulation results show that the improved harmonic current detection algorithm and control algorithm are advanced and effective.

5209Stereotactic radioablation of ventricular tachycardia guided by direct integration of 3D electroanatomic mapping: development and validation of a new method

Abstract Background Stereotactic body radiotherapy (SBRT) has emerged as a promising bailout therapy for recurrent ventricular tachycardia (VT) in patients with failed radiofrequency catheter ablation. However, SBRT can function only if the ablation target is precisely identified. Purpose We sought to develop a novel method for direct integration of electroanatomic mapping (EAM) data to an SBRT work station for radioablation of VT. Methods Candidates for SBRT were patients with recurrent, drug-resistant VT who underwent ≥2 previous radiofrequency catheter ablations (CARTO 3, Biosense-Webster, Diamond Barr, CA) and continued to have inducible clinical VT or clinical recurrences of VT. At the end of the last catheter ablation, the operators performed additional EAM to obtain landmarks for image registration: aorta with the ostium of the left main coronary artery or left atrium with ostia of pulmonary veins. Correct position of the catheter at the landmark was verified by intra-cardiac echocardiography. VT substrate–defined by a combination of voltage mapping, pace mapping, and detection of local abnormal ventricular activity and/or late potentials was marked by custom tags as a target for SBRT. The CARTO maps were exported and converted to 3D shells with encoded EAM properties (VTK format). On the following day, the patients underwent contrast-enhanced computer tomography (CT) of the heart. Using 3D Slicer software 4.10 (slicer.org), the EAM-derived anatomical structures with the marked ablation target were projected onto CT images by landmark registration with manual correction. The CT study with the projected contours of the EAM-detected ablation target was imported as a DICOM-RT format into a stereotactic radiotherapy planning work station (Multiplan 3.5, Accuray, Sunnyvale, CA). SBRT was performed using a contemporary radiosurgery system with real-time motion tracking of the ablation target (CyberKnife 8.5, Accuray). The prescribed (X-ray) dose was 25 Gy during a single session. Results The proposed work-flow was verified in four patients with structural heart disease and drug-resistant VT who had 2–3 unsuccessful radiofrequency catheter ablations (all males; age: 68–78 years; left ventricular ejection fraction: 20–25%; ischemic/non-ischemic cardiomyopathy: 2/2). Integration of EAM data with CT was achieved in all patients. None of them experienced acute radiotoxicity after SBRT. At a follow-up checkup at one month, three of the patients remained arrhythmia-free. One patient experienced VT recurrence one day after SBRT, but no VTs recurred during the following month of follow-up. Figure 1 Conclusions This is the first report demonstrating the feasibility of SBRT of VT guided by direct integration of EAM. The proposed method is best suited as a bailout procedure for patients with previously failed catheter ablation. Acknowledgement/Funding M.S. was supported by ESC Research Fellowship 2018