A new low drift integrator system for the Experiment Advanced Superconductor Tokamak

Liu, D. M.; Wan, B. N.; Wang, Y.; Wu, Yican; Shen, Biao; Ji, Zhenshan; Luo, Jiabei

doi:10.1063/1.3131627

Cited by 24 publications

(9 citation statements)

References 3 publications

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“…The drift performance of HL-2A DIM is adequate for current HL-2A experiments with discharge duration of less than 10 s. However, as reported recently [8][9][10], it is close to 0:07 lVs=s with integrators applied for longtime discharge of more than 1000 s. Also, unlike an analog integrator, which reduces the drift-to-signal ratio by decreasing the RC-time constant, a digital integrator has good drift performance just in applications of small signals such as diamagnetic measurement. Several methods can be considered to improve the drift performance.…”

Section: Resultsmentioning

confidence: 82%

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A multi-channel real-time digital integrator for magnetic diagnostics in HL-2A tokamak

et al. 2016

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A novel full-digital integrator has been developed for the magnetic diagnostics in HL-2A. Based on the pipeline processing of the field-programmable gate array and high-speed PCI extensions for instrumentation platform, the digital integrator has realized octal-channel 10-kHz real-time integration and data transmission. In order to reduce the integration drift, a 24-bit analog-todigital converter and simple analog processing circuits are applied for high-precision sampling, while certain correction algorithms are used to minimize the drift. With simple and highly integrated circuits and high-performance digital processor, the digital integrator is of high stability and functional expansibility which greatly simplifies the operation procedure. The digital integrator has been tested in the plasma discharge experiments, and the experimental results have confirmed that the drift performance and accuracy of the digital integrator could fully meet the requirements of HL-2A.

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Section: Resultsmentioning

confidence: 82%

“…Owing to the limitations of analog integration, integrators using digital techniques gain their popularity [7][8][9][10][11][12]. The principle of digital integration is to convert the analog signals into discrete digital signals by ADCs and accomplish numerical integration using digital processors and integration algorithms.…”

Section: Introductionmentioning

confidence: 99%

A multi-channel real-time digital integrator for magnetic diagnostics in HL-2A tokamak

et al. 2016

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“…The saddle loop output voltage is integrated with an integration time constant τ int = 10 ms by an analog integrator provided by Institute of Plasma Physics, Chinese Academy of Sciences. 11 The integrated signal,…”

Section: Experimental Set-upmentioning

confidence: 99%

Analytical compensation of axisymmetric equilibrium fluxes picked up by locked mode detectors in tokamaks

Ding

Wang

Ren

et al. 2014

Review of Scientific Instruments

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In the detection of locked modes using saddle loops, the problem of how to remove the axisymmetric equilibrium flux picked up by the loops has still to be solved. The problem becomes more difficult when there are conductive structures located near the saddle loops. In this paper, we present an analytical model based on lumped eddy current circuits and use it to interpret the measured equilibrium flux and the corresponding eddy current fluxes. Using this model, precise compensation for fluxes induced by the horizontal field coils and the toroidal field coils, with relative errors of less than 1%, has been realized for the saddle loops in the Joint Texas Experimental Tokamak. This paper also presents a new method to compensate for the detection of equilibrium flux by the locked mode detector.

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“…However, the integrator drift is an inevitable problem for the analog integrator, especially in the long-pulse cases. Much effort has been devoted to eliminate the drifts in the integrators, such as pre-compensation method, 2-4 analogy integration method which involves switching between two integrators through digital compensation of the drift, 5 and hybrid digital-analog method which measures both signal and drift alternatively 6 or continuously 7 and correct signal accordingly.…”

Section: Introductionmentioning

confidence: 99%

Development of a low-drift integrator system on the HL-2A tokamak

Yang

et al. 2016

Review of Scientific Instruments

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In this work, we developed a new integrator system with low-drift and small integration time constant less than 1 ms, which applies to the weak signals from magnetic measurements. This integrator system is designed on the basis of the analog drift compensation and the real-time digital correction of residual drift. The analog drift compensation is achieved by the subtraction between two integrators and the digital correction method is available due to the stability of integral drift in short time scale. The algorithm of the residual drift calculation and correction is implemented by the field programmable gate array. The integral drift can be well compensated within 10 mV/10 s at RC = 0.5 ms and meet the requirements of magnetic diagnostic on HL-2A.

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A new low drift integrator system for the Experiment Advanced Superconductor Tokamak

Cited by 24 publications

References 3 publications

A multi-channel real-time digital integrator for magnetic diagnostics in HL-2A tokamak

A multi-channel real-time digital integrator for magnetic diagnostics in HL-2A tokamak

Analytical compensation of axisymmetric equilibrium fluxes picked up by locked mode detectors in tokamaks

Development of a low-drift integrator system on the HL-2A tokamak

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