Among the symmetries in physics, the rotation symmetry is most familiar to us. It is known that the spherical harmonics serve useful purposes when the world is rotated. Squeeze transformations are also becoming more prominent in physics, particularly...
This paper investigates a back-electromotive force (EMF) harmonic compensation strategy for six-phase permanent-magnet synchronous motors (PMSMs) to reduce current harmonics and improve system performance. Ideally, the back-EMF waveform should be per...
The algebraic and differential SO3-invariants of spherical harmonics are studied in this work. The fields of rational algebraic and rational differential invariants and their applications for the description of regular SO3-orbits of spherical harmoni...
The use of multipoles, otherwise called spherical wavefunctions, has been explored for acoustic fields that can be omnidirectional, for example, in scattering theory. Less developed is the use of spherical harmonic multipoles for the construction of...
In this paper, we analyze the constraints of harmonics control in power electronic systems. Based on an equivalent circuit of a typical power converter application and its parameters, we have derived an analytical expression for calculating the maxim...
This paper proposes a compact rectifier design method for utilizing harmonics. Based on total reflection generated by pure reactance loads at the second harmonic (2nd) and open circuit at the third harmonic (3rd), a compact DC-pass filter is designed...
Harmonic estimation is essential for mitigating or suppressing harmonic distortions in power systems. The most important idea is that spectrum analysis, waveform estimation, harmonic source classification, source location, the determination of harmon...
For improving the performance of a doubly fed induction generator (DFIG) system under a harmonically distorted grid, this paper proposes a coordinated control strategy which is effective for grid inter-harmonics as well as grid integer harmonics. In...
In the case of adjustable drives systems with an induction motor (IM), a harmonic regime is manifested, whose knowledge and analysis are always necessary. However, most studies are focused on specific drive systems, the results of these works being v...
This paper presents the time-dependent variance in the current harmonics emission by power supplies during power quality measurements. Power quality problems are becoming more significant with the adoption of power electronic-based circuits such as p...
This paper considers the method for the calculation of magnetic flux density in the vicinity of overhead distribution lines which takes into account the higher current harmonics. This method is based on the Biot–Savart law and the complex image...
We present some addition theorems for spin-weighted spherical harmonics, generalizing previous results for scalar (spin-zero) spherical harmonics. These addition theorems involve sums over the azimuthal quantum number of products of two spin-weighted...
The studies of the high-order harmonics generated in Se-containing plasmas are reported. The ablation of selenium in a vacuum allowed for the formation of a plasma demonstrating high-order harmonics generation and resonance enhancement of the harmoni...
This article presents information about harmonic distortion and resonance in distribution networks. The theory behind harmonics and resonance is presented. Examples from the literature and the results of power quality measurements, as well as the aut...
In this study, the feedback effects of a three-phase half-controlled rectifier (also known as a semiconverter) to three-phase AC power grid was analyzed. Special attention was paid to the identification of harmonic order of the phase current. As a re...
Modern multiphase electric machines take advantage of additional degrees of freedom for various purposes, including harmonic current injection to increase torque per ampere. This new approach introduces a non-sinusoidal air gap flux density distribut...
The analyses of the influence of spatial harmonics on the electromagnetic torque of the multi-phase induction machine and reducing this influence are important tasks to ensure the high efficiency of the induction machine. Designing the machine to con...
This paper proposes a current harmonic suppression strategy that combines harmonic synchronous rotating frame (HSRF) current feedback control and back-electromotive force harmonic (BEMFH) feedforward compensation to suppress the fifth and seventh cur...
Understanding magnetic interparticle interactions within a single hydrodynamic volume of polydispersed magnetic nanoparticles and the resulting nonlinear magnetization properties is critical for their implementation in magnetic theranostics. However,...
This paper proposed an improved control method for grid-connected voltage source converter (VSC), when the grid voltage consisted of the integer harmonics and inter-harmonics. Control object of the proposed control can be alternated to achieve the si...
The four-dimensional ellipsoid of an anisotropic hyper-structure corresponds to the four-dimensional sphere of an isotropic hyper-structure. In three dimensions, both theories for spherical and ellipsoidal harmonics have been developed by Laplace and...
This paper presents a new winding with a low higher spatial harmonics content. This winding enables the elimination of the fifth harmonic, as the most significant, in three-phase winding and the third harmonic in two-phase symmetrical winding. The su...
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...
A three-phase three-wire voltage source converter (VSC) can produce third harmonics when it is operated under an unbalanced condition. It is essential to understand the mechanism of the production of this third harmonic and to assess its impact on po...
Cumulative second harmonic of ultrasonic guided waves is considered to have great application potential in evaluating internal stress of structures. One difficulty with the application is the diversity and complexity of modal response to the stress c...
We demonstrate the variations of single harmonic resonance enhancement during high-order harmonics generation in zinc-containing atomic and molecular species at the conditions of single-color and two-color pumps of laser-induced plasmas by applying d...
The integration of renewable energy generation and nonlinear power electronic equipment into the grid brings about complex harmonics and interharmonics problems. The amplitude and frequency of harmonics and interharmonics should be detected by high t...
In this paper, a robust estimation method for estimating the power system harmonics is proposed by using the optimal finite impulse response (FIR) filter. The optimal FIR filter is applied to the state space representation of the noisy current or vol...
With the advancing integration of fluctuating renewables, a more dynamic demand-side, and a grid running closer to its operational limits, future power system operators require new tools to anticipate unwanted events. Advances in machine learning and...
In this work, methods are implemented to improve two aspects of energy quality in a wind generation system. First, the harmonic reduction is achieved by applying a linear control technique in the Grid Side Converter; and second, the power factor of t...
Since the electro-hydraulic servo shaking table came into existence, many nonlinear elements, such as, dead zone, friction and backlash, as well as its acceleration response has higher harmonics which result in acceleration harmonic distortion, when...
High-order harmonic generation with high photon flux has been a challenging task in strong-field physics. According to the high-order harmonic generation process, the essential requirements for achieving efficient harmonic radiations inside a gas med...
We report on observations of single spike spectra (3–13% of events) upon employing a previously proposed method for single spike generation via harmonic conversion. The method was tested at the soft X-ray SASE3 undulator of the European XFEL. T...
Carbon-containing plasma is an attractive medium for generation of harmonics of laser pulses in the extreme ultraviolet range. We ablate two metal carbide (B4C and Cr3C2) nanoparticles and silicon carbide (SiC) nanoparticles and generate harmonics af...
The Euler–Bernoulli theory of beams is usually presented in two forms: (i) in the linear case of a small slope using Cartesian coordinates along and normal to the straight undeflected position; and (ii) in the non-linear case of a large slope using c...
This paper addresses a modeling and analysis methodology for investigating the stochastic harmonics and resonance concerns of wind power plants (WPPs). Wideband harmonics from modern wind turbines (WTs) are observed to be stochastic, associated with...
For homogeneous driving, half cycle harmonics and its corresponding half cycle cutoff (HCO) show prominent spectral features, allowing one to produce an isolated attosecond pulse with suitable filtering, or vice versa the retrieval of the driving pul...
The bridge arms and DC voltage of China’s Four-Terminal Flexible DC Transmission Project exhibit persistent high-frequency harmonics over the medium to long term, causing issues such as overheating losses and electromagnetic interference within...
In this paper, primary and secondary emissions in wind power plants are studied by using transfer admittance and current transfer functions between turbines and the public grid. The use of such transfer functions allows harmonic propagation studies w...
Batteries in energy storage systems are exposed to electrical noise, such as alternating current (AC) harmonics. While there have been many studies investigating whether Lithium-ion batteries are affected by AC harmonics, such studies on Nickel Metal...
Current harmonics is one of the most significant power quality issues which has attracted tremendous research interest. Shunt active power filter (SAPF) is the best solution to minimize harmonic contamination, but its effectiveness is strictly depend...
We theoretically explore a scheme for generation of bright circularly and elliptically polarized high-order harmonics by bursts of linearly polarized pulses with a rotating polarization axis. Circularly polarized harmonics are formed if the bursts ar...
Grid impedance is an important parameter and is used to perform impedance-based stability analysis for the operation of grid-connected systems, such as power electronics-interfaced solar, wind and other distributed power generation systems. The ident...
This article presents the impact analysis of space harmonics’ presence on a single-sided three-phase linear induction motor, along with a comprehensive parametric investigation. The presence of space harmonics often reduces the linear induction...
This paper presents the validation and characterization of a wavelet based decomposition method for the assessment of harmonic distortion in power systems, under stationary and non-stationary conditions. It uses Wavelet Packet Decomposition with Butt...
In the motor drive system of electric vehicles, there are some nonlinear factors, such as the deadtime and the conduction voltage drop of switching devices, which will generate low-order harmonics of the stator current and the torque ripple. The freq...
This paper proposes the study and analysis of harmonics, energy consumption and power quality of light emitting diode (LED) lamps equipped in building lighting systems. LED lamps with external (LED MR16) and internal (LED light bulb) drivers are inve...
The aim of this study was to obtain accurate angular positions and velocities from resolver signals; resolver-to-digital conversion (RDC) often adopts a phase-locked loop (PLL) as a demodulation algorithm. However, resolver signals often come with qu...
Precise torque control without pulsations is one of the major quality issues in pulse-width modulated voltage-source inverter (PWM-VSI) drives. Theoretically, it could be postulated that at frequencies of some kHz, the machine’s inertia absorbs switc...
High-order harmonics in the traction power supply show negative effects on the safe and stable operation of the railway transportation system. There is a fixed resonant frequency in the traction network. When the harmonic current frequency produced b...
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