Control Strategies for Multilevel APFs Based on the Windowed-FFT and Resonant Controllers

Han, Yang

doi:10.6113/jpe.2012.12.3.509

Cited by 6 publications

(3 citation statements)

References 14 publications

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“…The Hamming window with a wider main lobe and lower side lobe peak value is used to add window and framing to the numerical simulation internal leakage signal of a large-diameter pipeline ball valve. The expressions of Hamming window in the time domain and frequency domain are shown in Formulas ( 16) and ( 17), respectively [30,31]:…”

Section: Windowed Fft Frequency Division Processingmentioning

confidence: 99%

Multi-Leakage Source Localization of Safety Valve Based on Uniform Circular AE Array and Improved MUSIC Algorithm

Hou

Liu

2023

Sensors

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The safety valve is the core component of the pressure-relief protection device for pressure-bearing special equipment. When the safety valve leaks, the medium of the pressure vessel will be lost and wasted, which may cause safety accidents. With the aim to solve the problem of accurately locating the multiple leakage sources of safety valves, a localization method combining a uniform circular array acoustic emission detection and an improved multiple signal classification (MUSIC) algorithm is proposed. First, an improved wavelet threshold function denoising method is introduced to extract acoustic emission signals with high SNR, thereby reducing the rank of the covariance matrix, weakening the noise dispersion caused by eigenvalue reconstruction, avoiding signal and noise cross-confusion, and improving positioning accuracy. By introducing a windowed fast Fourier transform (FFT) frequency division processing link to obtain narrowband signal, the premise of using MUSIC positioning algorithm is established. In addition, a forward/backward spatial smoothing algorithm is introduced in the decoherence link to reduce co-channel interference, reduce the rank loss of the signal covariance matrix, and improve the positioning accuracy of the algorithm. The results show that when the working pressure is 0.70 MPa, 0.75 MPa, and 0.80 MPa, the deviation between the azimuth angle and elevation angle positioning results of each leakage source obtained by the improved MUSIC algorithm and the actual angle does not exceed 2°, and the relative error does not exceed 3.5%. Therefore, the improved MUSIC algorithm can accurately locate multiple leakage sources of the safety valve, and as the working pressure of the safety valve increases, the positioning accuracy of the improved MUSIC algorithm also increases accordingly.

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Section: Windowed Fft Frequency Division Processingmentioning

confidence: 99%

Multi-Leakage Source Localization of Safety Valve Based on Uniform Circular AE Array and Improved MUSIC Algorithm

Hou

Liu

2023

Sensors

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“…In fact, frequency domain methods are reasonably efficient for performing stochastic analysis. A Fast Fourier Transform (FFT) is usually employed to transform the time domain signal to a spectrum distribution on a linear frequency domain [10,11]. Therefore, the dynamic characteristics of a system could be roughly shown by the power spectral density (PSD) transformed from experimental data.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Modeling and Identification of an Electric-Hydraulic Controlled Fuel Injection System

Lee¹

2014

AMR

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Fuel consumption, related to engine operation and performance, has always been emphasized in the modern design of heavy vehicles. For identifying the operational mechanism of a novel hydraulically actuated electronic unit injection (HEUI) system from the viewpoint of energy conversion, this study presents the estimation of a nonlinear autoregressive moving average with exogenous inputs (NARMAX) models. By this modeling approach, the correlation between injection pressure and fuel rate under normal operations is detected. When mapping the NARMAX models into the frequency domain, the frequency response functions (FRFs) representing the energy transfer mechanisms in the system can then be precisely obtained. Due to the high-order FRFs responsible for the non-linear coupling between the various input spectral components, the HEUI dynamics can be demonstrated as an energy resonance of 22.5 Hz.

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“…Due to the wide application of power electronic loads such as switching mode power supplies, light controllers, interruptible power supplies, electric furnaces, ac voltage regulators and adjustable speed drives, a large amount of harmonic current or voltage is produced and reflected into distribution and transmission networks, which degrades the power quality [1], [2]. In order to mitigate harmonics, different configurations of active and passive filters have been proposed for different applications.…”

Section: Introductionmentioning

confidence: 99%

Control Strategy and Characteristic Analysis of Hybrid Active Power Filters with the Resonant Impedance Principle

Xu¹,

Luo²,

Li³

et al. 2012

Journal of Power Electronics

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A new kind of resonant impedance type hybrid active filter (RITHAF) is proposed for dynamic harmonic current suppression and high capacity reactive compensation in medium and high voltage systems. This paper analyzed the different performance of the RITHAF when the active part of the RITHAF is controlled as a current source and as a voltage source, respectively. The harmonic suppression function is defined in this paper. The influences of the changes caused by the grid impedance and the detuning of the passive power filter on the compensating characteristics of the RITHAF are studied by analyzing the suppression function. Simulation and industrial application results show that the RITHAF has excellent performances in harmonic suppression and reactive compensation, which is suitable for medium and high voltage systems.

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Control Strategies for Multilevel APFs Based on the Windowed-FFT and Resonant Controllers

Cited by 6 publications

References 14 publications

Multi-Leakage Source Localization of Safety Valve Based on Uniform Circular AE Array and Improved MUSIC Algorithm

Multi-Leakage Source Localization of Safety Valve Based on Uniform Circular AE Array and Improved MUSIC Algorithm

Dynamic Modeling and Identification of an Electric-Hydraulic Controlled Fuel Injection System

Control Strategy and Characteristic Analysis of Hybrid Active Power Filters with the Resonant Impedance Principle

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