Harmonic Sequence Research Articles

Third harmonic current minimization using third harmonic blocking transformer

Zero sequence blocking transformers (ZSBTs) are used to suppress third harmonic currents in 3-phase systems. Three-phase systems where single-phase loading is present, there is every chance that the load is not balanced. If there is zero-sequence current due to unequal load current, then the ZSBT will impose high impedance and the supply voltage at the load end will be varied which is not desired. This paper presents Third harmonic blocking transformer (THBT) which suppresses only higher harmonic zero sequences. The constructional features using all windings in single-core and construction using three single-phase transformers explained. The paper discusses the constructional features, full details of circuit usage, design considerations, and simulation results for different supply and load conditions. A comparison of THBT with ZSBT is made with simulation results by considering four different cases.

АКУСТИЧЕСКИЙ ЭКСПРЕСС-АНАЛИЗ КАЧЕСТВЕННОГО И КОЛИЧЕСТВЕННОГО СОСТАВА ПОЧВ ПРИ СТРОИТЕЛЬНЫХ РАБОТАХ

An express analysis of the ecological state of the soil during construction works is proposed. The algorithm is considered, which is the first approximation for describing the quality of the soil mixture, serving to build a system of operational recognition of the component composition of the soil mixture and the percentage of its main components. It is based on the analysis of the forced acoustic emission signal in the frequency domain to obtain the Fourier spectrum. From the general spectrum of the signal, consisting of a set of basic and higher (timbre) harmonics, subspectrs of significant basic harmonics corresponding to certain elements of the soil mixture are distinguished. To isolate the sub-spectra, a sequence of modal harmonics is used. The composition of the set of modal harmonics determines the qualitative composition of the soil in the first approximation.

Harmonic contribution determination based on change‐point monitoring and shape context algorithm

In the power system, the harmonic is one of the important concerns of power quality, which has a significant impact on the safe operation of power grids and the energy efficiency for users. When there are not enough special harmonic monitoring devices installed on public transport, it is important to identify the harmonic source and assess the harmonic contribution based on the load data of the user's electricity meter. This paper proposes a data selection and matching idea based on change-point monitoring (CPM), canonical correlation analysis (CCA) and dynamic adjusted shape context (DASC) for determining the harmonic contributions of individual customers and utilities. In the proposed approach, the CPM is used to select the valuable data by detecting the violent fluctuation area of harmonic voltage and the DASC to determine the harmonic contribution of individual customers by matching the user load sequence and harmonic voltage sequence based on CCA, filtering the harmonic contribution from the utility side. Simulation data is used to evaluate the performance of the method and a real-world case study is also conducted. It is found that the proposed technique can be used to reveal the harmonic impact of the loads if data is selected resonably.

Bayesian approach for the optimal control of high-order harmonics for the generation of ultrashort attosecond laser pulses

We present an efficient and powerful method to optimize the production of high-order harmonic generation (HHG) and the synthesis of an isolated attosecond pulse. The system under investigation is the helium atoms that are exposed to the combination of chirped two-color mid-IR laser field and its 1s–2p transition frequency. An ab initio study is conducted by solving the three dimensional time-dependent Schrödinger equation accurately and efficiently by means of the time-dependent generalized pseudospectral method. We applied Bayesian optimization to obtain an optimal laser waveform to generated a HHG spectrum with enhanced harmonics and extended cutoff frequency. Harmonic phases are analysed by the wavelet transform. We demonstrated that an isolated 10 attosecond pulse can be synthesized using a sequence of consecutive and phase-locked harmonics in the plateau region.

Tonal harmony and the topology of dynamical score networks

I introduce the concept of dynamical score networks for the representation and analysis of tonal compositions: a score is interpreted as a dynamical network where every chord is a node and each progression links successive chords. This network can be viewed as a time series of a non-stationary signal, and as such, it can be partitioned for the automatic identification of tonal regions using time series analysis and change point detection without relying on comparisons with pre-determined reference sets or extensive corpora. I demonstrate that the essential features of tonal harmony, centricity, referentiality, directedness and hierarchy, emerge naturally from the network topology and its scale-free properties. Finally, solving for the minimal length path through a route optimization algorithm on these graphs provides an abstraction of harmonic sequences that can be generalized for the conception of generative models of tonal compositional design.

Hermite–Hadamard–Fejér-Type Inequalities and Weighted Three-Point Quadrature Formulae

The goal of this paper is to derive Hermite–Hadamard–Fejér-type inequalities for higher-order convex functions and a general three-point integral formula involving harmonic sequences of polynomials and w-harmonic sequences of functions. In special cases, Hermite–Hadamard–Fejér-type estimates are derived for various classical quadrature formulae such as the Gauss–Legendre three-point quadrature formula and the Gauss–Chebyshev three-point quadrature formula of the first and of the second kind.

PERFORMING SKILLS OF ACCORDIONIST IN THE CONTEXT OF PROFESSIONAL TRAINING OF A TEACHER-MUSICIAN

The article emphases the importance of training a teacher-musician, improving the quality of his education by achieving the necessary competencies, one of which is instrumental performance. The basic conditions that affect the development of performing skills of the future teacher are analyzed in the work, which are mastering strong knowledge from the cycle of cultural, musicological and psychological and pedagogical disciplines, closely related to the certain historical period, society, way of life, socio-historical conditions, creative environment, etc., which form the basis of the performing culture of the teacher and instrumentalist. The main factors of development and improvement of performing skills are highlighted, which include technologies of sheet music reading and study of accordion instrumental works. The concept of "intonation", which has been the subject of research by many scientists, musicologists, composers, performers, is described as one of the most effective ways for a composer to create a musical image through which the whole mechanism of reproducing the content and emotional depth of musical works. The article contains examples of "deciphering" intonation by expressive properties in the process of interpreting the work, when the performer becomes a co-author of the composer, penetrating the musical image through knowledge of styles, genres, expressive properties of the system and its tendencies, intervals, chords, harmonic sequences, expressive properties of intonation in the whole complex of performing.

Falling Up

This article investigates melodic figures and harmonic sequences that miraculously only step up to illuminate an aesthetic lineage that connects gospel to electronic dance music. It argues that the synth-risers and ever-opening filters of contemporary euphoric rave music like happy-hardcore and uplifting-trance find precedence in compositional devices that made their way into funk/soul and disco/garage from Black gospel music, and that these gospel inventions were derived from the Afro-diasporic ring-shout. Cognitive linguistic and psychoacoustic theories premise an analytical framework for musical representations of endless ascent. Through close readings of representative recordings—a 1927 Pentecostal sermon by Reverend Sister Mary Nelson, James Cleveland’s “Peace Be Still,” Chic’s “Le Freak,” Trussel’s “Love Injection,” and DJ Hixxy’s remix of Paradise's “I See the Light”—the article examines various historical intersections with parlour music, European art music, and modal jazz, and suggests that musical ascent has a non-causal but, nevertheless, objective relationship with a type of spiritual transcendence.

Stator Faults Detection on Induction Motors Using Harmonic Sequence Current Components Analysis

In this paper we propose a strategy for detecting interturn short circuits on stator windings of three-phase induction motors (IM). The strategy is based on an analytical model that includes a stator fault in any of the phase windings considering the h-th harmonic in the supply voltage. To find the adequate model, we propose an equivalent electrical circuit of the IM in steady state, considering each sequence component. The proposed strategy allows the detection of an interturn short-circuit fault by monitoring the fifth-order harmonic component. We present simulation and experimental results for the faulty IM and different operating conditions. In the laboratory tests, we use a programmable power supply in order to synthesize distorted and unbalance voltages. Also, the windings of a three-phase IM have been modified to generate stator faults and validate the proposed model. The results show that the sustained increase of the fifth-order harmonic of positive-sequence current is a good indicator of the fault severity.

Wintgen ideal submanifolds: New examples, frame sequence and Möbius homogeneous classification

In real space forms, any submanifold must satisfy the so-called DDVV inequality which relates the scalar curvature, the mean curvature, and the scalar normal curvature pointwise. When the equality is attained at each point, it is called a Wintgen ideal submanifold. This property is invariant under the conformal transformations. So we try to give a complete classification of this class of submanifolds. This is done under the additional assumption of Möbius homogeneity in this paper. Some new interesting examples are constructed using the real representation of SU(2), which turn out to constitute the majority of Möbius homogeneous Wintgen ideal submanifolds. The classification follows by constructing a frame sequence. This reveals a wonderful connection with the classical harmonic sequence of Riemann surfaces.

Empirical comparison between stochastic and deterministic modifiers over the French Auvergne geoid computation test-bed

Since 2006, several different groups have computed geoid and/or quasigeoid (quasi/geoid) models for the Auvergne test area in central France using various approaches. In this contribution, we compute and compare quasigeoid models for Auvergne using Curtin University of Technology’s and the Swedish Royal Institute of Technology’s approaches. These approaches differ in many ways, such as their treatment of the input data, choice of type of spherical harmonic model (combined or satellite-only), form and sequence of correction terms applied, and different modified Stokes’s kernels (deterministic or stochastic). We have also compared our results with most of the previously reported studies over Auvergne in order to seek any improvements with respect to time [exceptions are when different subsets of data have been used]. All studies considered here compare the computed quasigeoid models with the same 75 GPS-levelling heights over Auvergne. The standard deviation for almost all of the computations (without any fitting) is of the order of 30–40 mm, so there is not yet any clear indication whether any approach is necessarily better than any other nor improving over time. We also recommend more standardisation on the presentation of quasi/geoid comparisons with GPS-levelling data so that results from different approaches over the same areas can be compared more objectively.

ГАРМОНИЯ В МУЗЫКАЛЬНОМ ПРОИЗВЕДЕНИИ – ОТКРЫТАЯ СИСТЕМА С НЕИСЧЕРПАЕМЫМ ПОТЕНЦИАЛОМ

The article discusses the possibilities of constructing a harmonic series of a musical composition. These opportunities turn out to be almost inexhaustible. Oriented on the statement of Marchetto of Padua ("The ear is the best judge"), we see in such a potential of harmonic sequences the limitless potential of colors accompanying melodic constructions In the development of a composer in a particular text of a different panorama of harmonic transitions are involved, first of all:. 1) enharmonic, 2) major-minor system, 3) a system of tonal connections parallel – eponymous – one-tone tonalities.

One-Step-Prediction Discrete Observer Based Frequency-Locked-Loop Technique for Three-Phase System

In grid-tied power converters, the grid parameters such as the frequency, phase angle of the fundamental component, and the harmonics are essential to the control of power converters, the fast and accurate estimation of the grid parameters is a challenge especially for high-order harmonics. This paper proposes a one-step-prediction (OSP) discrete observer (OSPDO) to observe the fundamental and harmonic sequence components of the grid voltage. Based on the proposed OSPDO, a frequency locked loop (FLL) is designed. The proposed OSPDO-FLL has a good robustness to sampling frequency on dynamic response and high precision for frequency estimation. The proposed algorithm can estimate up to maximum 50th harmonic with a low sampling frequency thanks to the robust properties. Finally, the good characteristics of the proposed synchronization algorithm are verified by simulations and laboratory experiments.

Design of an Enhanced FLC-Based Controller for Selective Harmonic Compensation in Active Power Filters

The increasing number of electronic loads has introduced several harmonics into the power system, leading to a growth in the importance of filters intended for their mitigation. Thus, it is important to have the knowledge to select operational limits of each new filter connected in the power grid. Likewise, obtaining these harmonics requires robust tracking systems that provide enough information for better filter selectivity. This paper proposes a selective harmonic active filter control based on Fourier linear combiner (FLC) algorithms for a three-phase electrical grid. The presented system is enabled to track each harmonic order and sequence components with great robustness, extracting positive, negative, and zero sequence information from each harmonic for further filter selectivity. It also proposes a new strategy to improve the FLC-based algorithms in tracking frequencies in power grid disturbances. Simulated results of the algorithm and a real-time simulation of a selective active power filter (SAPF) were presented, validating the performance in several scenarios.

Characterizing plurality using the majoritarian condition: a new proof and implications for other scoring rules

Plurality rule selects whichever alternative is most preferred by the greatest number of voters. The majoritarian principle states that if a simple majority of voters agree on the most preferred alternative, then it must be selected uniquely. Lepelley (RAIRO-Recherche Operationnelle 26: 361–365, 1992) adopts a proof by contradiction approach to show that plurality is the only scoring rule satisfying the majoritarian principle. We make use of the relationship that majoritarianism implies faithfulness to present a new proof allowing us to derive limits on the size of the group for which a particular scoring rule will satisfy majoritarianism without restricting voter preferences. We then determine the limits for three specific faithful scoring rules where voters rank the alternatives: positive/negative voting, wherein one point is awarded to a voter’s top preference and one point is subtracted from a voter’s bottom preference; Borda, in which an equal increase in points is awarded to each successively higher rank; and Dowdall, for which rank points entail an harmonic sequence. Comparing these rules by the sizes of group and alternative set combinations for which they are majoritarian we find that Borda is dominated by positive/negative voting, and both are dominated by Dowdall. We also derive the relative point gaps between certain pairs of rankings beyond which a scoring rule will not be majoritarian for any group of more than two voters.

Forecasting the Reliability of Components Subjected to Harmonics Generated by Power Electronic Converters

This paper aims at refining an experimentally based reliability model for the insulation of power components subjected to the randomly varying harmonics generated by power electronic converters. Compared to previous papers of the same authors and to the existing literature, here the model is re-formulated from the theoretical viewpoint focusing on the foremost role played by low percentiles of time to failure—in particular by the 1st percentile—selected as the rated life in the framework of modern probabilistic design of components. This is not only more correct from the viewpoint of component design, but also on the safe side as for the reliability of devices. Moreover, the application of the model is broadened to treat the whole sequence of odd voltage harmonics from the 5th to the 25th, i.e., those taken as the most significant in power systems according to international standards. The limits to voltage distortion set in Standard EN50160 are the reference for establishing parametrically a series of typical distorted voltage waveshape analyzed in the applicative part, which account for the possible phase-shift angles between voltage harmonics. The effect of current harmonics is also considered, from both the theoretical and applicative viewpoint. As a last, but not least novelty, the reliability model is used here for life and reliability estimates not only of Medium Voltage (MV)/Low Voltage (LV) capacitors and cables—already studied in the previous stages of this investigation—but also of induction motors and transformers in the presence of harmonics from power converters.

An Ultrasound Enhancing Agent with Nonlinear Acoustic Activity that Depends on the Presence of an Electric Field

The nonlinear acoustic properties of microbubble ultrasound enhancing agents have allowed for the development of subharmonic, second harmonic, and contrast-pulse sequence ultrasound imaging modes, which enhance the quality, reduce the noise, and improve the diagnostic capabilities of clinical ultrasound. This study details acoustic scattering responses of perfluorobutane (PFB) microbubbles, an un-nested perfluoropentane (PFP) nanoemulsion, and two nested PFP nanoemulsions—one comprising a negatively charged phospholipid bilayer and another comprising a zwitterionic phospholipid bilayer—when excited at 1 or 2.25 MHz over a peak negative pressure range of 200 kPa to 4 MPa in the absence and presence of a 1-Hz, 1-V/cm electric field. The only sample that exhibited an increase in nonlinear activity in the presence of an electric field at both excitation frequencies was the negatively charged nested PFP nanoemulsion; the most pronounced effect was observed at an excitation of 2.25 MHz. Interestingly, the application of an electric field not only increased the nonlinear acoustic activity of the negatively charged nested PFP nanoemulsion but increased it beyond that seen when the nanoemulsion is un-nested and on the same scale as PFB microbubbles.

Common-Mode Insertion Indices Compensation With Capacitor Voltages Feedforward to Suppress Circulating Current of MMCs

In order to improve the efficiency of modular multilevel converters (MMCs) and reduce the capacitor voltage ripples, the circulating current between the phase-legs should be suppressed. In existing circulating current suppression control (CCSC) methods, multiple resonant regulators or dq-frame integrators are usually employed to reduce the harmonic components. Besides the complexity, it requires additional designs of controller parameters, which relies on accurate frequency and sequence information of the circulating currents. In this paper, a common-mode (CM) insertion indices compensation method is introduced to realize CCSC, which is based on feeding forward the capacitor voltages. This approach not only facilitates the analysis of circulating current mechanism with a deep insight, but also provides a simple approach to achieve a wide bandwidth circulating current suppression without considering the specific harmonic frequencies and sequences. The latter one makes it easy to be used even in the unbalanced, multi-frequency or variable fundamental frequency ac systems. In addition to these advantages, the proposed compensation method can maintain inter-arm capacitor voltages balanced without additional differential energy control loop, which is required in the existing capacitor voltage feedforward scheme. Analytical and extensive simulation results are given for validating the effectiveness of the proposed approach.

Efficient Communication in Written and Performed Music.

Since its inception, Shannon's information theory has attracted interest for the study of language and music. Recently, a wide range of converging studies have shown how efficient communication pervades language, from phonetics to syntax. Efficient principles imply that more resources should be assigned to highly informative items. For instance, average information content was shown to be a better predictor of word length than frequency, revisiting the famous Zipf's law. However, in spite of the success of the efficient communication framework in the study of language and speech, very little work has investigated its relevance in the analysis of music. Here, we examine the organization of harmonic information in two large corpora of Western music, one made of MIDI files directly sequenced from scores, and the other made of MIDI recordings of live performances of highly skilled piano players. We show that there is a clear positive relationship between (contextual) information content of harmonic sequences and two essential musical properties, namely duration and loudness: the more unexpected a harmonic event is, the longer and the louder it is.

The hyperspace of [formula omitted]-closed subcontinua

The concept of T-closed set of a continuum was defined and studied by D.P. Bellamy et al. in [1], where T denotes the Jones's set function. Given a continuum X, in this paper we define the hyperspace CT(X) as the collection of all T-closed subcontinua of X. We present examples of continua X for which this hyperspace has n elements for each positive integer n or it is the closure of the harmonic sequence or it is the Cantor set. We study the connectedness, compactness and density of CT(X). Finally, we relate the continuity of T with the structure of this hyperspace.