• Title, Summary, Keyword: Current signal

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Variable-magnitude Voltage Signal Injection for Current Reconstruction in an IPMSM Sensorless Drive with a Single Sensor

  • Im, Jun-Hyuk;Kim, Sang-Il;Kim, Rae-Young
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1558-1565
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    • 2018
  • Three-phase current is reconstructed from the dc-link current in an AC machine drive with a single current sensor. Switching pattern modification methods, in which the magnitude of the effective voltage vector is secured over its minimum, are investigated to accurately reconstruct the three-phase current. However, the existing methods that modify the switching pattern cause voltage and current distortions that degrade sensorless performance. This paper proposes a variable-magnitude voltage signal injection method based on a high frequency voltage signal injection. The proposed method generates a voltage reference vector that ensures the minimum magnitude of the effective voltage vector by varying the magnitude of the injection signal. This method can realize high quality current reconstruction without switching pattern modification. The proposed method is verified by experiments in a 600W Interior permanent magnet synchronous machine (IPMSM) drive system.

CMOS Switch-Current Square Base on Switch Current

  • Parnklang, Jirawath;Muenpan, Sombat;Kumwatchara, Kiatisak;Channarong, Sakonwan
    • 제어로봇시스템학회:학술대회논문집
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    • pp.318-318
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    • 2000
  • Current signal square based on switch current is presented in this article. This is the new technique that can design current signal square circuit by using switch-current memory cell, current square and sample and hold technique, which have been presented by the general switch-current. This principle which is present have the good electrical characteristics such as the low input impedance, high output impedance and high frequency response. The system can also operate in the audio frequency range to the high frequency current signal. The system application of this technique can be apply to the current signal multiplier by quarter square technique. The experimental results agree well with the theory as high accuracy and linearity.

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DC Current sensor using the saturable magnetic cores (자성체포화를 이용한 DC전류센서)

  • Park, Y.T.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.699-702
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    • 2002
  • A DC current sensor is disclosed in which two pairs of saturable cores are provided so as enclose a conductor carrying a direct current to be measured. On each of the saturable cores, a bias winding, a feedback winding and an output winding are wound. Circuit for detection of an asymmetry in the magnetization current, generated by a reference alternating voltage, in a signal-conditioner. The reference alternating voltage is fed to the respective series circuits such that no resultant induction current is induced in the modulating current. The voltages over the resistor form input signals for two peak value detectors, the strength of the output signal of which represents the degree of asymmetry of magnetization current. This paper describes the development a DC current sensor and its signal-conditioner.

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Analysis of Parameter Effects on the Small-Signal Dynamics of Buck Converters with Average Current Mode Control

  • Li, Ruqi;O'Brien, Tony;Lee, John;Beecroft, John;Hwang, Kenny
    • Journal of Power Electronics
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    • v.12 no.3
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    • pp.399-409
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    • 2012
  • In DC-DC Buck converters with average current mode control, the current loop compensator provides additional design freedom to enhance the converter current loop performance. On the other hand, the current loop circuit elements append substantial amount of complexity to not only the inner current loop but also the outer voltage loop, which makes it demanding to quantify circuit and operating parameter effects on the small-signal dynamics of such converters. Despite the difficulty, it is shown in this paper that parameter effects can be analyzed satisfactorily by using an existing small-signal model in conjunction with a newly proposed simplified alternative. As a result of the study, new insight into average current mode control is uncovered and discussed quantitatively. Measurable experimental results on a prototype averaged-current-mode-controlled Buck converter are provided to facilitate the analytical study with good correlation.

An Excessive Current Subtraction Technique to Improve Dynamic Range for Touch Screen Panel Applications

  • Heo, Sanghyun;Ma, Hyunggun;Bien, Franklin
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.16 no.3
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    • pp.375-379
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    • 2016
  • A current subtraction technique with parallel operation system is proposed to remove excessive current in touch screen application. The proposed current subtraction remove the current which go into the input node of charge amplifier. The value of subtraction current is same with current when touch screen is not touched. As a result, charge amplifier output is only proportional to variation of mutual capacitor, which make dynamic rage is increased. Also, Transmitter (Tx) driving signal and subtraction driving signal are out of phase each other. Thus, noise generated in Tx is cancelled. The proposed IC is implemented in a mixed-mode 0.18-um CMOS process. Overall system is designed for touch screen panel (TSP) with 16 driving lines and 8 sensing lines. 5-V supply voltages are used in the proposed circuits. For multiple Tx driving signal, Walsh codes are used and signal frequency is 300 khz. By using proposed technique, dynamic rage is improved 36 dB.

A Study on the Machining characteristics in the Cylindrical Plunge Grinding using Spindle Motor Current Signal (주축모터전류신호를 이용한 원통 연삭시 가공 특성에 관한 연구)

  • 김남훈
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.507-512
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    • 1999
  • In modern engineering practice, the grinding process is one of the most important and widely used operations for the precision finishing of components. In this paper, machining characteristics of external plunge grinding were investigated by using spindle motor current signal through hall sensor. Grinding experiments were performed in terms of various grinding conditions such as wheel speed, workpiece speed, infeed rate and spark-out time with conventional vitrified bonded WA wheel. The relationship between spindle motor current signal and metal removal rate in terms of infeed rate was induced the by analyzing spindle motor current signal.

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A New Small Signal Modeling of Average Current Mode Control

  • Jung, Young-Seok;Kang, Jeong-Il;Youn, Myung-Joong
    • Proceedings of the KIPE Conference
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    • pp.609-614
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    • 1998
  • A new small signal modeling of an average current mode control is proposed. In order to analyze the characteristics of the control scheme, the discrete and continuous time small signal models are derived. The derivation are mainly come from the analysis of the sampling effect presented in the current control loop. By the mathematical interpretation of practical sampler representing the sampling effect of a current control loop, the small signal models of an average current mode control can be easily derived. The instability of the current control loop, which gives rise to the subharmonic oscillation, can be identified by the proposed models. To show the usefulness of the proposed models, the simulation and experiment are carried out. The results show that the predicted results by the proposed model are much better agreed with the measured ones than that of the conventional model, even though the high gain of the compensation network of a current control loop is employed.

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A Novel Parameter-independent Fictive-axis Approach for the Voltage Oriented Control of Single-phase Inverters

  • Ramirez, Fernando Arturo;Arjona, Marco A.;Hernandez, Concepcion
    • Journal of Power Electronics
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    • v.17 no.2
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    • pp.533-541
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    • 2017
  • This paper presents a novel Parameter-Independent Fictive-Axis (PIFA) approach for the Voltage-Oriented Control (VOC) algorithm used in grid-tied single-phase inverters. VOC is based on the transformation of the single-phase grid current into the synchronous reference frame. As a result, an orthogonal current signal is needed. Traditionally, this signal has been obtained from fixed time delays, digital filters or a Hilbert transformation. Nevertheless, these solutions present stability and transient drawbacks. Recently, the Fictive Axis Emulation (FAE) VOC has emerged as an alternative for the generation of the quadrature current signal. FAE requires detailed information of the grid current filter along with its transfer function for signal creation. When the transfer function is not accurate, the direct and quadrature current components present steady-state oscillations as the fictive two-phase system becomes unbalanced. Moreover, the digital implementation of the transfer function imposes an additional computing burden on the VOC. The PIFA VOC presented in this paper, takes advantage of the reference current to create the required orthogonal current, which effectively eliminates the need for the filter transfer function. Moreover, the fictive signal amplitude and phase do not change with a frequency drift, which results in an increased reliability. This yields a fast, linear and stable system that can be installed without fine tuning. To demonstrate the good performance of the PIFA VOC, simulation and experimental results are presented.

The Study on Reliability Improvement in Eddy Current Inspection by Signal Characteristic Optimization of Multi-coil Array Probe (다중센서 신호특성 최적화를 통한 와전류검사 신뢰성 개선연구)

  • Ahn, Y.S.;Gil, D.S.;Park, S.G.
    • Journal of the Korea Society For Power System Engineering
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    • v.14 no.2
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    • pp.60-64
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    • 2010
  • This paper introduces reliability improvement and time saving in eddy current inspection by signal characteristic optimization of multi-coil eddy current array probe. In the past, Multi-coil array probe and single probe were used for the gas turbine rotor surface inspection & defect evaluation. The multi-coil array probe was used for the broad area inspection. But the signal deviations among multi-coil array probe are maximum 28% in commercial probe. This differences were considered to impedance differences among coils, so it is very difficult to evaluate exact defect size. The signal deviations among multi-coil array probe are maximum 28% in commercial probe. So, single coil inspection was used for exact defect sizing. The purpose of this study is to improve signal deviations of multi-coil array probe. The introduced new technology can improves this deviation by adjusting input voltage in each coil. At first, apply same voltage in each coil and collect signal amplitude of each coil. And calculate new input voltage based on signal amplitude of each coil. If the signal amplitude deviation is within 5% among multi-coil array probe, the signal amplitude of multi-coil array probe is reliable. The proposed technology gives 2% signal deviation among multi-coil array probe. The proposed new technology gives reliability improvement and inspection time saving in eddy current inspection.

Modeling of Heart Phantom using the Multidipole Current Source

  • Jang, Kwan-Hee;Yoon, Dal-Hwan;Min, Seung-Gi
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1957-1962
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    • 2003
  • In order to design the phantom of heart, we have developed the multi-dipole current source system. Such a one be clue to the various motion of heart. The magnetocardiograph (MCG) system for diagnosing the disease of the heart due to an analysis of the heart signal. The multidipole current source system be built by microprocessor. We use the shield room to obtain a good experimental result. Then the signal acquired is mixed with a background noise, through a filtering extracts a pure signal. The pure signal such a heart phantom is analyzed by an electromagnetic map.

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