Measured Voltage Waveforms Research Articles

Effect of direct voltage induction by low-frequency security systems on neurostimulator lead.

Low-frequency (LF) security systems, such as antitheft electronic article surveillance (EAS) gates emit strong magnetic fields that could potentially interfere with neurostimulator operation. Some patients reported pain and shocking sensations near EAS gates, even after they turned off their pulse generator. To investigate the direct voltage induction of EAS systems on neurostimulator leads, we evaluated voltages induced by two EAS systems (14 kHz continuous wave or 58 kHz pulsed) on a 40 cm sacral neurostimulator lead formed in a circular loop attached to a pulse generator that was turned off. The lead and neurostimulator were mounted in a saline-filled rectangular phantom placed within electromagnetic fields emitted by EAS systems. The measured voltage waveforms were applied to computational models of spinal nerve axons to predict whether these voltages may evoke action potentials. Additional in vitro testing was performed on the semicircular lead geometry, to study the effect of lead geometry on EAS induced voltages. While standard neurostimulator testing per ISO 14708-3:2017 recommends electromagnetic compatibility testing with LF magnetic fields for induction of malfunctions of the active electronic circuitry while generating intended stimulating pulses, our results show that close to the EAS antenna frames, the induced voltage on the lead could be strong enough to evoke action potentials, even with the pulse generator turned off. This work suggests that patient reports of pain and shocking sensations when near EAS systems could also be correlated with the direct EAS-induced voltage on neurostimulator lead.

AC Series Arc Fault Modeling for Power Supply Systems Based on Electric-to-Thermal Energy Conversion

The measured voltage waveform of the arc fault for the 220 V power supply system is continuous but non-smooth which is hard to be reproduced with the traditional arc models. Consequently, this paper proposes an arc model based on electric-to-thermal energy conversion. Both the heat convection loss and the heat conduction loss are considered in this arc model. This proposed arc model is specially used to simulate the arc-circuit interaction during the whole development process of the continuous-arc-fault for the 220 V power supply system. Due to the fact that this proposed arc model is a multivariable-nonlinear differential equation, this paper proposes a computation method based on the current region splitting according to the non-smooth connections of the measured voltage waveform. The model parameters can be adjusted independently in each current region. Then the comparisons between measurements and the arc model results are given which show a good agreement in the all current regions. In addition, the effective estimations for the arc geometrical and electrical parameters are achieved based on this proposed arc model. Finally, experimental results validate that the arc model and the corresponding computation method proposed in this paper are general and effective for the 220 V power supply system.

Self-Calibration Method of Noncontact AC Voltage Measurement

Realizing stable and reliable monitoring of a distribution network voltage environment can obtain real-time power parameter information and ensure the normal and safe operation of transmission lines, which is of great research significance and engineering value. Based on the distributed capacitance relationship between sensor and transmission line, an equivalent circuit capacitance voltage dividing model is proposed, and the relevant factors affecting the stability of the voltage dividing ratio are analyzed. The self-calibration principle of noncontact AC voltage measurement is proposed based on the system identification theory. The noncontact sensing structure is designed, a sensor probe prototype is fabricated, and a back-end conditioning circuit is designed to realize the overall measurement system. Finally, the validity of the measurement model is verified by simulation and experiment, and a measurement platform is built which proves the feasibility of the self-calibration method for noncontact voltage measurement. The experimental results show that the error is less than ±2%. This method can correctly restore the measured voltage waveform, has good linearity, and can realize wireless data transmission, which provides a new idea for the voltage measurement method of a distribution network.

전기설비에서 전압변동을 이용한 직렬아크 검출방법

According to the Fire Statistical Yearbook, Electric arcs, such as ignition sources, are a high proportion in Korean fire accidents. Because it is important to detect the arcs prior to the fire accidents, sensors and frequency analysis have been studied to detect them. The arc detection techniques based on the sensors and frequency analysis are limited in location search and reliability in arc detection, respectively. Therefore, it is necessary to study an improved technique for detecting the arc. This paper proposes an arc detection technique that can improve the location search and the low reliability in the arc detection using the voltage fluctuations. The experiments were conducted to obtain the voltage fluctuations from the measured voltage waveforms under conditions with or without an arc for the loads defined in IEC 62606, thereby checking the presence of the arc. We confirmed that the proposed arc detection technique can detect a series arc in electric equipment.

An equivalent discharge model of electrostatics spark

Electrostatic sparks are considered to be mainly resistive. However, experimental results show that the oscillation frequencies and amplitude attenuation of fitted waveform based on underdamped oscillation have discrepancies comparing with measured voltage waveform if spark gap is replaced by a pure resistance. To study the phenomenon, a simple device was built for strong electrostatic spark discharges of short discharge times. An equivalent discharge model including variable spark resistance and spark inductance was made to simulate the spark discharge. By comparative experiments under different ambient humidity, electrode gaps and charging capacitances, an exponential relationship between spark resistance and spark inductance with discharge time was verified.

Three-level NPC Inverter SVM Implementation on Delfino DSC

The aim of the paper is to present implementation of reduced switch count space vector pulse width modulation for three-level neutral point clamped inverters (3L-NPC). The implementation was done using Delfino TMS320F28379D. This dual core digital signal controller (DSC) is used because of compute-intensive nature of implemented modulation. In presented solution the space vector pulse width modulation uses prediction algorithm to reduce the number of individual state changes in power transistors (switch count). This implementation is made because lower number of transistor switching reduces switching losses. The algorithm makes use of additional sets of transistors’ states corresponding to voltages at the output of inverter. Measurements of voltage waveforms and execution time of transistors control algorithm are presented in this paper. Obtained results indicate possibility of further optimization of THD levels and switch count reduction on used DSC.

Real-time system for automatic detection and classification of single and multiple power quality disturbances

It is known that the quality of power has been the subject of several researches aiming to provide relevant information to users of electrical systems that are becoming increasingly smart. This study presents an approach for single and multiple power quality disturbance detection and classification using multidimensional analysis, higher-order statistics and a neuro-tree based classifier. The system was implemented in an FPGA (Field Programmable Gate Array), a real-time processor and a remote computer, with LabVIEW interface. This implementation enables real-time execution and its application to monitor smart grids. It is able to detect deviations in the measured voltage waveform from the nominal one and classify 20 classes of single and multiple disturbances with a global efficiency upper to 97%.

Design and research of a three‐phase voltage sensor based on D‐dot principle

In the design of three‐phase D‐dot voltage sensor based on electric field coupling, both effects of both the adjacent phase electric fields and distribution parameters on measurement should be taken into consideration. This paper builds a simulation model and a physical measuring system of a three‐phase sensor, measures the effect of the distribution parameters by the simulation model, and finally finds the transfer function between the input and output voltage signals of the circuit. The measured voltage waveforms and parameters can be reflected by the physical measuring system. Our results provide a theoretical basis for the design of a three‐phase D‐dot voltage sensor. And the measuring system can achieve multipoint synchronous acquisition and ensure less distortion. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Electron heating enhancement due to plasma series resonance in a capacitively coupled RF discharge: Electrical modeling and comparison to experimental measurements

The electron heating enhancement due to the self-excitation of the plasma series resonance in capacitively coupled plasmas is revisited by a combination of an equivalent circuit model and experiments. To improve the model accuracy, measured voltage waveforms at the powered electrode are used instead of prescribing a sinusoidal voltage supply in series with a bias capacitance. The results calculated from the electrical model are consistent with the experimental measurements performed by a Langmuir probe with verification of a microwave interferometer, at pressures of 0.2 and 0.3 Torr. High harmonics occurring in the discharge currents agree with observations in previous research. The nonlinear plasma series resonance effect is found to have a notable contribution to both ohmic and stochastic heating evaluated by the electron heating efficiencies.

Fast Power Semiconductors Switching Current Measurement by Current Surface Probe

With the advantage of high bandwidth and small insertion impedance, a current surface probe (CSP) used to measure switching current waveforms is presented in this paper. Its transfer impedance is characterized and validated by measuring an IGBT switching current that is compared with those obtained with a current probe (CP), a current shunt (CS) and a Hall effect current probe (HECP). Furthermore, by comparing with a CS to measure a GaN-HEMT switching current, it is shown that CSP is able to measure a switching current of a few nanoseconds, while it brings no influence on transistor voltage waveform measurement. The obtained results show that, the use of CSP brings little parasitic inductances in the measurement circuit and it does not bring the connection of the ground to the power converter, which is the case for the CS.

Design and finite element analysis of a hybrid excitation synchronous machine

The paper presents a hybrid excited synchronous generator (HESG) with field windings and permanent magnets. This paper focuses on the analysis in the operating principle, rotor shape optimization, and inductance characteristic, based on finite element method. The measured voltage waveforms suggest that the rotor shape optimization in the study is a feasible solution to improve the quality of output voltage. Both the simulation and the tested results on generator performance verify further that the electric excitation can efficiently adjust the air-gap flux. Compared to conventional electric excited synchronous generator, the load capacity is improved due to relatively low armature inductance of the HESG.

Using Current Surface Probe to Measure the Current of the Fast Power Semiconductors

With the advantage of high bandwidth and small insertion impedance, a current surface probe (CSP) used to measure switching current waveforms is presented in this letter. Its transfer impedance is characterized and validated by measuring an IGBT switching current that is compared with those obtained with a current probe and a Hall effect current probe. Furthermore, by comparing with a current shunt to measure a GaN-HEMT switching current, it is shown that CSP is able to measure a switching current of a few nanoseconds, while it brings no influence on transistor voltage waveform measurement. The obtained results show that the use of CSP brings little parasitic inductances in the measurement circuit and it does not bring the connection of the ground to the power converter.

English

The present paper presents an accurate hybrid framework capable to rapidly detect, classify & locate short- circuit faults on transmission lines. The proposed algorithm has employed the values resulted from each three- phase currents wavelet transform in order to obtain instantaneous fault detection. Singling out short-circuit faults based on the measured voltage waveforms and three-phase current is done when fault events occur in power transmission lines. The energy derived from three-phase currents and three-phase voltages wavelet transform has been used as the classification algorithm input .Then fault location has been activated as the result of fault classification method. Combining the methods such as multilevel wavelet transform, multilayer perceptron neural network in a set has been utilized to determine short- circuit fault type and location at the moment of occurrence. The accuracy and superiority of the present paper derived results due to the fundamental wavelet transform concepts as an excellent feature extractor have been compared with those of another paper exploiting Fourier transform.

A Fully Integrated Transformer-Coupled Power Detector With 5 GHz RF PA for WLAN 802.11ac in 40 nm CMOS

This paper introduces a fully integrated direct power detector that monitors both RF current and RF voltage to detect the RF output power of the on-chip RF PA realized in a standard 40 nm CMOS process. The RF current measurement is realized by a sense winding in the output transformer, while the RF voltage waveform measurement is performed by capacitive division of the RF output voltage. Since the RF current and the RF voltage are both acquired, this power detector accurately and continuously determines the real output power of the RF PA with a maximum inaccuracy of ±0.5 dB over a wide 32.5 dB dynamic range. This power detector was integrated together with a 5 GHz RF PA designed for the WLAN IEEE 802.11ac communication standard. The power detector is capable of performing a RF output power measurement even for an antenna impedance mismatch up to voltage standing wave ratio (VSWR) 2.8:1 with an accuracy of ±1 dB, which allows the power detector to be used in an automatic antenna-mismatch correction system to prevent performance degradation in the RF PA. Finally, since the proposed power detector can be completely incorporated inside the RF PA output transformer. It results in zero area overhead, proving a very cost effective design.

A Fast Voltage Clamp Circuit for the Accurate Measurement of the Dynamic ON-Resistance of Power Transistors

For determining the dynamic on -resistance $R_{{\rm dyn},{\rm on}}$ of a power transistor, the voltage and current waveforms have to be measured during the switching operation. The novel heterostructure wide-bandgap (e.g., AlGaN/GaN) transistors inherently suffer from the current collapse phenomenon, causing the dynamic on -resistance to be different from the static. Measuring voltage waveforms using an oscilloscope distorts the characteristics of an amplifier inside the oscilloscope when the range of the measurement channel is not set wide enough to measure both on -state and off -state voltage levels, resulting in failure to accurately measure the voltage waveforms. A novel voltage clamp circuit improving the accuracy of the transistor's on -state voltage measurement is presented. Unlike the traditional clamping circuit, the presented voltage clamp circuit does not introduce delay caused by $RC$ time constants, keeping the voltage waveform clear, even during state transitions of the device under test. The performance of the presented circuit is illustrated by measurements on a 2-MHz inverted buck converter.

Effect of an external magnetic field on plasma torch discharge fluctuation

The effect of an external magnetic field on the anodic arc root movement inside a dc plasma torch has been investigated. In this letter, a virtual instrument technology was used to measure the arc voltage of the plasma torch at atmospheric pressure, and the rotating frequency of the anodic arc root was estimated by high-speed photography. The arc voltage fluctuation which represents the degree of the arc instability was reduced. And a new peak, whose frequency is consistent with the rotating frequency of the anodic arc root, was found in the Fast Fourier Transform spectra of the arc voltage signal. From the results, the helical instability generated directly by anodic arc rotation is put forward, and only the appropriate external magnetic field could inhibit and reduce the instability of the plasma torch and prolong the life of the anodic electrode. Furthermore, the measured voltage waveforms indicated that the arc root attachment mode would be controllable by an external magnetic field.

Application of a Josephson quantum voltage source to the measurement of microsecond timescale settling time on the Agilent 3458A 8 digit voltmeter

The voltage waveform measurement characteristics due to finite settling time on the microsecond timescale are investigated for the Agilent 3458A 8 digit voltmeter in DCV mode. A quantum-accurate voltage synthesizer based on the Josephson effect produces a change in test voltage in less than 1 μs and the voltage reported by the voltmeter is measured as a function of two timing parameters, aperture delay and duration. A model is presented and the level of agreement is discussed in the context of optimizing the configuration of the instrument for both high measurement throughput and accuracy.

Design, deployment and verification of the capacitive voltage divider for measuring fast transient occurrences in the nanosecond range

This paper discusses the design, development, testing, recording and verification of the capacitive voltage divider for measuring fast transient occurrences in the nanosecond range. Basic constructional data and essential electrical properties of the capacitive divider are provided, along with details on how to determine them. Special attention is devoted to the capacitive divider’s constructional limits in regard to the expected measurement uncertainty, the choice of an appropriate low-voltage capacitor material and its influence on the capacitive divider’s response. Results for the divider’s response to 1.2/50μs, 300/1000ns and 5/50ns waveforms are given in the experimental part of the paper. It is shown that the divider with the proposed construction transmits signals well, except for signals in the sub-nanosecond range. Moreover, it is shown that the divider transmits signals extremely well in the nanosecond range, in which case it is necessary to couple the divider directly to the measuring point, since reflection and refraction of the measured voltage waveform in galvanic leads has to be avoided.

Wireless Power Transmission Using Ultrasonic Guided Waves – Electric Circuit Measurement and Simulation

A project investigating the possibility to transmit electrical power (several mW) along the structure of an aircraft by using an intermediate medium of ultrasonic Lamb waves is being carried out at Cardiff University in conjunction with Airbus. This power supply method is aimed at wireless, surface-bonded sensor packages, primarily for the aircraft structural health monitoring (SHM) applications. It is expected to replace conventional batteries or energy harvesting devices. This paper presents methods of piezoelectric transducer characterisation, electric power measurement and electric circuit simulation that were developed in support of the ultrasonic power transmission project. The unique combination of low power and a high AC frequency range (up to 200 kHz) precluded the use of conventional power measurement instruments and called for a tailored system and software to be developed. Two approaches were developed: one relying on the measurement of the ultrasonic transducers impedance characteristics and their subsequent use in a circuit simulation; and another relying on the direct measurement of voltage waveforms in the power transmission setup. The two methods were found to be capable of producing closely matching results up to 300 kHz. Results of early power transmission trials are also presented. The optimum approach resulted in 1 mW of power transmission over a distance of 74 cm in a 1.5 mm thick aluminium plate.

計測分圧回路を考慮した配電系電力状態計測センサの数値電界解析

We have proposed and preproducted the voltage-current waveform sensor of resin molded type for measuring the power factor and harmonics in power distribution systems. We have executed numerical electromagnetic analyses using the finite element method to estimate the characteristics and behaviours of the sensor. Although the magnetic field analyses for the current sensor have involved the measurement circuit, the electric field analyses have not included the measurement circuit for measuring voltage waveforms of power lines. In this paper, we describe the electric field analyses with the measurement circuit and prove the insulating strength of the proposed sensor permissible to the use in 22kV power distribution systems.