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Synchronous power systems often experience two types of oscillatory responses: natural and forced. Natural oscillations are a transient response characterized by the electromechanical oscillation modes. If one or more of these modes are undamped, a sustained oscillation occurs with the system in a near unstable condition. Alternatively, forced oscillations are typically caused by some rouge input...
This paper presents power system frequency estimation by using a Modified Non-Linear Least Square (MNLS) Technique. The proposed approach uses a variable and dynamically changing A matrix as per the sampling instant. So less memory is required for storage of A matrix. The performance of the proposed method is better under all conditions as compared to NLS method. The performance of the proposed method...
This paper promotes a better understanding of the power grid quality and dynamics through the introduction of a newly developed Universal Grid Analyzer (UGA). The UGA is a real-time, highly accurate, and GPS synchronized power grid monitoring device used at distribution level. They can function as a power quality analyzer by performing harmonics measurement along with voltage sag and swell detection...
Power system current and voltage signals contain valuable information about the system status within their small random fluctuations. Frequency domain analysis of these so-called noise signals enables us to monitor the power cable health. This paper proposes a new passive methodology for online power cable diagnosis by resonant frequency analysis. The feasibility of this methodology is proved by analytic...
Fast and accurate detection of instantaneous reactive current in single-phase power system is a pre-requisite for the precise control of STATCOM (Static Synchronous Compensator). A major solution is based on the construction of virtual orthogonal signal in rotational coordinate transformation; however, conventional methods show weaknesses in the speed of detection and the ability of noise and harmonic...
In this paper, different strategies for the calculation of the Harte's Harmonic Change Detection Function (HCDF) are discussed. HCDFs can be used for detecting chord boundaries for Automatic Chord Estimation (ACE) tasks, where the chord transitions are identified as peaks in the HCDF. We show that different audio features and different novelty metric have significant impact on the overall accuracy...
The paper deals with a systematic observer design for a robust frequency identification of electromechanical systems. The observer estimates the frequency response of the system which is excited by a swept harmonic signal with a variable frequency, amplitude and DC component. The paper presents a computationally efficient algorithm based on the recursive discretization of a Kalman filter. An application...
Contour-based Fourier descriptors are very simple and effective shape description method used for content-based image retrieval. Similarity between Fourier descriptors is usually computed using measures such as City-block or Euclidean distance. These similarity measures consider all harmonics to be equally important, therefore harmonics with larger magnitude tend to have larger significance during...
In this paper, a wide-band fully differential linear low noise amplifier (LNA) in a standard 130nm CMOS process is presented. The LNA utilizes Active Post Distortion (APD) as a voltage combiner that prepares a linear transconductance for enabling harmonic cancellation, which can also mitigate the impedance matching device noise. The impedance matching device is connected to the output transistors...
Contour-based Fourier descriptors are established as a simple and effective shape description method for content-based image retrieval. In order to achieve invariance under rotation and starting point change, most Fourier descriptor implementations disregard the phase of the Fourier coefficients. We introduce a novel method for extracting Fourier descriptors, which preserve the phase of Fourier coefficients...
The characteristic of radial electromagnetic force and torque ripple of permanent magnet assisted synchronous reluctance motor (PMSynRM) under load condition was analyzed; considering to minimize the radial electromagnetic force and torque ripple, An effective and detailed method of suppressing vibration of PMSynRM was proposed. The validity of the proposed method is confirmed by both simulated and...
This paper proposes a new continuous-time (CT) MASH delta sigma (ΔΣ) modulator topology in which dual VCO-based quantizers are incorporated. The nonlinearity of both voltage-controlled oscillators (VCOs) caused by their nonlinear voltage-to-frequency (V-to-F) transfer curve are systematically suppressed without any calibration schemes. After the input voltage is directly digitized by a VCO-based quantizer...
Frequency drift is an important issue and is difficult to be avoided in ADC testing. The power leakage caused by frequency drift in the ADC output spectrum cannot be removed by conventional methods. This paper proposes a new algorithm which can estimate the ADC specifications accurately when there is frequency drift. The output of the ADC is collected as Ks segments. Phase correction is applied to...
With the wireless power transfer (WPT) upgrade and improve, WPT systems will be widely the load of transformers. When a transformer is connected to a WPT system, the vibration noise from the transformer core will increase because of the harmonics generated by the load. In the field of transformers with multistep-lap cores, magneto-elastic vibration is mainly caused by magnetostriction. It is feasible...
This paper presents a novel method to solve the estimation of the amplitudes and phases of different harmonic components contained in a power electrical signal, based on Particle Swarm Optimizer with Natural Selection (PSONS). PSONS is an Evolutionary Algorithm (EA) with the natural selection mechanism. The proposed method utilizes PSONS to estimate the phases of the harmonics and a standard least-square...
The paper describes algorithms of the nonparametric power estimation by summation of the products of the amplitude discrete Fourier transform (DFT) coefficients when simultaneously of sampling is assumed. As with energy-based approach for the amplitude square estimation of the one-channel signal, the apparent power in the two-channel case can be estimated with the multiplied amplitude DFT coefficients...
The new type of active noise feedforward control (new DXHS algorithm) was proposed and its local stability was analysed to show that the new algorithm can overcome drawbacks of filtered-x least mean square (FxLMS) algorithm as well as delayed-x harmonics synthesiser (DXHS) algorithm. This paper verifies with simulations and experiments how well the new DXHS algorithm works. For the simulations and...
In this paper we present a technique for underwater acoustic beamforming based on soundfield recording that encodes both the temporal and spatial characteristics of a signal. Here, we introduce the basic theory behind soundfield recording and present a first-order beamformer that beamforms the encoded data in a specific direction (θ,φ) and with a variable polar pattern, p. The appeal of this beamformer...
We review briefly basic Melnikov theory for both deterministic and stochastic systems. We then show how the theory can be used for the identification of a class of multistable systems for which experimental data are available on the relation between excitation frequency and rate of escape from a potential well. We illustrate our approach for the case of the auditory nerve fiber, for which the use...
The paper presents a new idea for coding of audio signals whose short-time spectrum is sparse, i.e. the energy is concentrated within few narrowband peaks. Typical examples are solo instrument parts with distinct harmonics as well as singing voices, especially in high registers. Such signals are often degraded by standard perceptual codecs that assume quite different spectral energy distribution....
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