Harmonic Resonance Research Articles

Harmonics suppression in high-speed railway via single-phase traction converter with an LCL filter using fuzzy logic control strategy

Introduction. The railway Traction Power Supply System (TPSS) encounters a common challenge related to high-frequency harmonic resonance, especially when employing AC-DC-AC traction drive systems in high-speed trains. This resonance issue arises when the harmonic elements introduced by the traction AC-DC converter on the grid side of trains align with the innate resonance frequency of the TPSS. The novelty the proposed work focuses on the challenges associated with resonance elevation and high-frequency harmonics in high-speed trains, while simultaneously enhancing energy quality. This is achieved by integrating a pulse-width-modulated converter on the grid side with a single-phase configuration and incorporating an LCL filter. Methodology. In order to optimize the system’s efficiency, a robust control system is employed, taking advantage of the capabilities of a fuzzy logic controller (FLC). The choice of the FLC is justified by its straightforward design and reliability, emphasizing the dedication to precise control, as fuzzy logic excels in handling complex, nonlinear systems. Through the use of linguistic variables and heuristic reasoning, the FLC adjusts to dynamic changes in the system, demonstrating its efficacy in enhancing both transient and steady-state responses. Practical value. A grid-side LCL filter-based converter was meticulously designed and rigorously simulated using the MATLAB/Simulink platform. The inclusion of an advanced FLC in the system introduced a novel approach to control strategies, surpassing the traditional PI controller. Through a comprehensive comparative analysis, the simulation results showcased the remarkable efficacy of the proposed solution in an effectively mitigating high-frequency resonance within the TPSS. This outcome underscores the potential of FLC as a sophisticated control mechanism for enhancing the performance systems in railway applications, showcasing its superiority over conventional control methods. The study contributes in shedding light on innovative approaches for optimizing the control and efficiency of grid-side LCL filter-based converters in high-speed train systems.

Harmonic resonances due to transmission-system cables

This paper gives some examples of harmonic issues that can occur when long ac cables are connected in the transmission grid. The main impact is that resonances can occur at much lower frequencies than when only overhead lines are present. Two illustrative case studies are presented: one for a 275-kV cable, one for a 400-kV cable in combination with a 132 kV capacitor bank. A simple rule-of-thumb is given, to decide if a detailed harmonic study is needed. Some guidelines for such a study are given as well.

Harmonic Resonance Study for Wind Power Plant

Harmonic resonance is one of an important aspect being considered in a large network such as a wind power plant (WPP). This paper analyses several factors that affect resonance characteristic in a WPP and possible mitigation measures. The first part of the paper provides an analysis of resonances in WPP. Two methods of identifying resonances are performed which are a common impedance scan method and a harmonic resonance modal method for different operating conditions. Several factors that affect resonances including the usage of passive filters as harmonic mitigation in the network are analyzed. A case study of a 400 MW offshore wind power plant is analyzed for the harmonic resonance including with the integration of a passive filter.

Expert System Design for Determining the Harmonic Resonance and the Capacitor Safety Level

This paper presents a computer based expert system aiming the determination of harmonic resonance and the capacitor safety level. Developed applications for the determination of harmonic resonance are basically depending on the selection of a right harmonic impedance measurement method and the changes observed in the equivalent system impedance due to the occurrence of harmonic resonance. However, developed applications for the determination of capacitor safety level are depending on the international standards which introduce the related indices and limits for the capacitors and the fuzzy logic method. All developed applications were programmed using LabVIEWTM and the data required, is obtained continuously from real-time measurements.

Nonlinear combined harmonic resonances of composite cylindrical shells operating in hygro-thermo-electro-magneto-mechanical fields

By considering the effects of the hygro-thermo-electro-magnetic environments, von Karman nonlinear terms, and multi-harmonic excitations, a coupled nonlinear vibration modeling of composite cylindrical shells comprising a carbon nanotube-reinforced composite (CNTRC) core and two piezoelectric/magnetic composite (PEMC) skins is developed, and the nonlinear dynamic behaviors of such cylindrical shells under primary, super/sub-harmonic, and combined resonance states are investigated. In the theoretical modeling process, the effective mechanical properties of the CNTRC core are first determined using the mixing and Schapery laws, and the hygro-thermo-electro-magneto-mechanical constitutive relations of the PEMC skins are then formulated. Within the framework of Reissner-Mindlin shell theory, the Lagrangian of the system containing Green-Lagrange and von Karman nonlinear terms is derived, and solution techniques based on the multiscale method are provided to obtain nonlinear frequencies, dynamic responses, and phases of CNTRC-PEMC cylindrical shells under multi-physics fields. Consequently, comparison studies are conducted to validate the correctness of the proposed model from different aspects. Based on this, various resonance and chaos behaviors of such structures subjected to multiple load components are revealed and compared, and the influences of environmental factors and structure composition on the amplitude-frequency curves, time-history responses, and phase planes are explored, with several recommendations and findings being drawn.

Sideband Harmonic Suppression Analysis Based on Vector Diagrams for CHB Inverters Under Unbalanced Operation

Unexpected sideband harmonics of the cascaded H-bridge (CHB) inverters will appear in unbalanced conditions among cells and may result in harmonic pollution and even harmonic resonance. The linear controller to suppress the output voltage distortion is destined to be ineffective due to the non-linear characteristic of sideband harmonics. Focus on this problem, this article proposes a closed-loop harmonic suppression method by adjusting the phase-shift angles for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> -cells CHB inverter. The harmonics suppression mechanism is revealed from a vector synthesis point of view. No complicated trigonometric function calculations and optimization algorithms are required. This method can achieve the suppression of the harmonic distortion around any multiplicative switching frequency. Phase-shift angles are adjusted continuously in real-time. The superior harmonic performance achieved by the proposed method is verified by the simulation and experiment results.

A Low-Phase-Noise VCO With Common-Mode Resonance Expansion and Intrinsic Differential 2nd-Harmonic Output Based on a Single Three-Coil Transformer

In this article, we propose a voltage-controlled oscillator (VCO) with a single three-coil transformer, featuring a common-mode (CM) resonance expansion and intrinsic differential 2nd harmonic output. In addition to a conventional transformer-based class-F resonator, an internal third coil is added to manipulate the CM response. On one hand, it expands the CM resonance bandwidth, eliminating the need for manual harmonic tuning to align the 2nd harmonic resonance. On the other hand, it creates a simultaneous wideband differential response at the 2nd harmonic frequency, therefore, the power consumption of the extra frequency doubler can be saved. Using the proposed stacked 8-shape inductor topology, the third coil can be placed inside the class-F transformer without consuming an extra chip area. Fabricated in a 65-nm CMOS process, the measured tuning range of the proposed VCO is 21.1%, from 12.3 to 15.2 GHz. The proposed VCO achieves a peak phase noise (PN) performance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 118.0 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 111.9 dBc/Hz at 1 MHz offset for fundamental frequency and 2nd harmonic, respectively, the corresponding peak figure-of-merit (FoM) of which is 190.4 and 190.1 dBc/Hz, respectively. The VCO consumes a power of 8.4–9.6 mW, while occupying a small area of 0.06 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}$</tex-math> </inline-formula> thanks to the stacked 8-shape inductor topology.

Harmonic Resonance Evaluation and Suppression for Interconnected System of Traction Substation Group in Weak Power Grid

Harmonic Resonance Evaluation and Suppression for Interconnected System of Traction Substation Group in Weak Power Grid

Analysis of Small-Disturbance Stability of Onshore Wind Power All-DC Power Generation System and Identification of Leading Factors

The application of conventional AC collection for the integration of large-scale renewable energy sources may lead to issues concerning harmonic resonance and reactive power transmission. Conversely, the utilization of an all-DC power generation system for wind power (WDCG) can effectively circumvent such issues. In contrast to the conventional power system, the interdependence among subsystems in the WDCG renders it susceptible to oscillation instability in the presence of minor disturbances. To address this concern, this paper first establishes a small-signal model for the WDCG, and validates the accuracy of this model by comparing it with an electromagnetic transient model based on PSCAD/EMTDC. Secondly, employing the eigenvalue analysis method, the principal oscillation modes of the WDCG are identified, and the state variables strongly correlated with these modes are analyzed using the participation factor method. Moreover, a quantitative assessment of the impact of operational and control parameters closely associated with the strongly correlated state variables on the negative damper oscillation model is conducted. The findings of the analysis reveal that the small-disturbance stability of the WDCG is significantly influenced by the operational parameters of the outlet capacitance of the ma-chine-side converter (MSC), the outlet capacitance of the direct current wind turbine (DCWT), the sub-module capacitance of the modular multilevel converter (MMC), and the inductance of the bridge arm. Additionally, the stability is al-so affected by the control parameters of the constant DC voltage control on the DCWT side, the voltage outer-loop–current inner-loop control, and the circulation suppression on the MMC side. The simulation results based on PSCAD validate the efficacy of the proposed method in identifying the dominant factors.

Dynamical behavior of a particle-doped multi-segment dielectric elastomer minimal energy structure

The dynamic behavior of dielectric elastomers (DEs) has significant influence on their performance. The present study investigates the nonlinear dynamics of particle-doped multi-segmented DE minimum energy structures (DEMESs). To simulate the multi-segment DEMES, we consider each segment as a combination of hyperelastic film and elastic beam and obtain the ordinary differential equations governing the system dynamics based on the Euler–Lagrange equations. Due to the difficulty in measuring various physical parameters of DEs in practice, we utilize experimental data from a single-segment DE and employ a physics-informed neural network to predict the unknown parameters of the DE and the framework, such as stiffness K bb and doping volume fraction ϕ. Based on these predictions, nonlinear analysis is performed for the multi-segment system. Stability analyses of the motion equations reveal that the system exhibits a supercritical pitchfork bifurcation with hyperelastic thin film pre-stretching as the bifurcation parameter. For the three-segment DEMES, there are eight stable modes, but only four are illustrated in the bifurcation diagram due to the identical parameter settings for each segment. The amplitude-frequency curves under different AC voltage loads indicate the presence of harmonic, superharmonic, and subharmonic resonances in the system, with varying frequencies and magnitudes depending on the applied load. The Poincaré maps of the time response demonstrate that the system response is predominantly quasiperiodic. Under low voltage loads, the system exhibits periodic oscillations, while under certain high voltage loads, chaotic behavior emerges, characterized by strong nonlinearity in the time-dependent curves and non-periodicity in the Poincaré maps. This study provides insights into the present mathematical model in the motion control of DEMES.

Impact of interaction between RF waves and fast NBI ions on the fusion performance in JET DTE2 campaign

This work presents a study of the interaction between radio frequency (RF) waves used for ion cyclotron resonance heating and the fast deuterium (D) and tritium (T) neutral Beam injected (NBI) ions in DT plasma. The focus is on the effects of this interaction, also referred to as synergistic effects, on the fusion performance in the recent JET DTE2 campaign. Experimental data from dedicated pulses at 3.43 T/2.3 MA heated at (i) 51.4 MHz, giving the central minority H and n = 2 D, and at (ii) 32.2 MHz for the central minority 3He and n = 2 T. Resonances are analysed and conclusions are drawn and supported by modelling of the synergistic effects. Modelling with transport code TRANSP runs with and without the RF kick operator predict a moderate increase, of about 10%, in DT rates for the case of the RF wave—fast D NBI ion interactions at the n = 2 harmonic of ion cyclotron resonance, and a negligible impact due to synergistic interaction between fast T NBI ions and RF waves. JETTO modelling gives a 29% enhancement in fusion rates due to the interction between RF waves and fast D NBI ions, and an 18% enhancement in fast T NBI ions. Analysis of experimental neutron rates compared to TRANSP predictions without synergistic effects and magnetic proton recoil neutron spectrometer indicate an enhancement of approximately 25%–28% in fusion rates due to RF interaction with fast D ions, and an enhancement of approximately 5%–8% when RF waves and fast T NBI ions are interacting. The contributions of various heating and fast ion sources are assessed and discussed.

New Reference Current Calculation Method of a Hybrid Power Filter Based on Customer Harmonic Emission

This paper presents a novel reference current calculation method for harmonics mitigation and reactive power compensation in power systems. This method was applied to a unique hybrid power filter topology. The motivation for this study comes from the increasing power quality issues, such as harmonic distortion and resonances, caused by the widespread integration of converter-interfaced generation (CIG) and modern nonlinear loads into the power system in recent years. The goal of this study is to propose a cost-effective and practical solution for current harmonics filtering and power factor correction by combining the advantages of passive and active filters into a hybrid solution. The developed reference current calculation method, which is based on customer current harmonic emissions, enables effective reference current calculation. Theoretical analyses along with simulation results obtained from a medium-voltage benchmark model in PSCAD verify the effectiveness of the proposed solution in harmonics filtering and show a substantial reduction in filter current ratings across various harmonic components. In addition, the simulation results were evaluated by comparison with the results obtained from a real-time simulator.

Passive Filter Tuning for Harmonic Resonance Mitigation in Wind Parks

Passive Filter Tuning for Harmonic Resonance Mitigation in Wind Parks

Enhancing interfacial Li+ transport and dielectric properties in poly(ethylene oxide)-based all-solid electrolytes via inactive g-C3N4 nanosheets filler incorporation

The advancement of all-solid-state Li metal batteries (ASSLMBs) faces a major challenge in the growth of lithium dendrites on the anode-electrolyte interface. In this study, we propose a dual-filler approach using poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) that combine Li1.4Al0.4Ti1.6(PO4)3 (LATP) ion-conductive particles with graphitic carbon nitride (g-C3N4) nanosheets. Analysis through second harmonic resonance enhanced electrostatic force microscopy and critical current density (CCD) tests reveal that the g-C3N4 additives form nano-capacitors at the SPE-lithium interface, effectively reducing sudden changes in current densities. The distribution of relaxation time constant (DRT) measurements confirms that the g-C3N4 filler suppresses uncontrolled Li dendrite growth, effectively mitigating battery aging caused by anode interfacial degradation. Furthermore, X-ray photoelectron spectroscopy (XPS) analysis indicates that the nitrogen-containing organic groups in g-C3N4 are reduced to form a stable interfacial layer with lithium metal. As a result of these enhancements, the electrolyte demonstrates remarkable interfacial stability in Li/Li symmetrical cells at 0.65 mA/cm2 and delivers promising performance in assembled Li-LiFePO4 batteries, achieving a reversible capacity of 121.6 mAh/g at 1 C after 200 cycles. These findings highlight the potential of dual-filler PEO-based SPEs for promoting interfacial lithium-ion transport in all-solid-state Li metal batteries.

Distributed damping reshaping control with constraints on dual stabilities for grid‐connected inverter in high penetration grid

SummaryThe penetration level is limited by the occurrence of harmonic resonance under weakening grid. Under conventional current control, the penetrations with different power scheduling are assessed by the impedance Bode diagrams. To further suppress the current harmonics and improve the penetration with minimum cost, this paper proposes a distributed damping reshaping method by introducing the grid current feedback loop into the modulated wave of the inverter. The additional feedback loop is obtained by moving forward the feedback point of real damping link in hardware loop. Its equivalent control block has actual physical meaning, which helps to design damping coefficient. Further, instead of relying on the experience of engineer to select the damping coefficient, considering the effect of different values of damping on the inverter's performance, a damping design principle with the dual constraints on GCI's self‐stability and the global stability of the system is proposed. In detail, the range of the possible values of damping can be obtained by setting the desired system phase margin and the desired GCI's pole‐zero locations. In this range, the damping parameter, which remains the maximum ability of harmonic suppression for penetration improvement, can be determined by setting the desired damping ratio of the poles near the imaginary axis. Finally, simulations and experimental results were conducted to verify the correctness of the theoretical analysis.

Higher-Frequency Permeability Measurement by Harmonic Resonance Cavity Perturbation Method

A new combination of electric field antenna and coupling hole plates are introduced to extend the measurable frequency range of rectangular waveguide type harmonic resonator to evaluate complex relative permeability of magnetic composites by perturbation method from 18 GHz to 38 GHz (K/Ka-band). The noise suppression performance parameter ωμ”=2πfμ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> ” [kΩ/m] is useful to estimate the performance of magnetic powder composite sheets especially beyond 10 GHz range where relative permeability is as small as 0-2. The ωμ” exhibited the maximum of 166 kΩ/m at 27 GHz for a carbonyl iron powder composite sheet, and as high as 510 at 38 GHz for Sendust sheet. These values meet ωμ”≥100 kΩ/m criteria that some commercially available noise suppression sheets exhibit in their recommended frequency range. These performance match Sub-6 GHz band and 28 GHz band used for 5G telecommunication equipment.

The harmonic resonance and singularity analysis of bifurcation for the magnetized elastic plate with action of time-varying magnetic potential

This paper deals with the superharmonic resonance of a ferromagnetic thin rectangular plate in the air-gap magnetic field excited by armature magnetic potential. Electromagnetic forces applied on the plate by the air-gap magnetic field cause the plate to transversal vibrate, which affects the air-gap magnetic field in turn, resulting the vibration and magnetic field coupling. According to the basic electromagnetic field theory and considering the magnetoelastic coupling effect, the air-gap magnetic field intensity is obtained by solving the Laplace's equation satisfied the air-gap magnetic boundary conditions. The electromagnetic force model of soft ferromagnetic plates is determined based on theories of electromagnetic and elasticity. According to the large deflection theory of plates, basic energy relationships and variational equations of the elastic plate are given. Eventually, the nonlinear magnetoelastic vibration equation of ferromagnetic thin plates is derived using Hamilton's principle and Galerkin method. The multi-scale method is used to solve the superharmonic resonance to obtain the amplitude-frequency response equation and the stability discriminant of solutions. The topological analysis of amplitude-frequency equation is carried out using singularity theory, and the bifurcation characteristics of systems on physical parameter planes in different regions are obtained according to the transition set. The correctness of analytical solutions is verified by comparison with numerical solutions. Through numerical calculations, curves of the static deflection and equivalent magnetic force of plate with parameters are given, and the amplitude curves, dynamic phase plane trajectories and time history diagrams of system response with changes in electromagnetic and structural parameters are plotted. Results show that both the decrease of armature magnetic potential amplitude and the increases of plate thickness and initial air-gap thickness reduce the static deflection. The increase of armature magnetic potential amplitude increases the equivalent magnetic force. As the decrease of initial air-gap thickness and the increases of armature magnetic potential amplitude and excitation force amplitude, the amplitudes of the upper branch and lower branch curves representing stable solutions decrease and increase, respectively, and the single-value solution region increases.

Wavenumber-frequency relationships in the cochlea: Measurements and models

A fundamental characteristic of cochlear mechanics is the traveling wave—a transverse wave which propagates from base to apex along the basilar membrane. Experiments and models have shown that its wavenumber (2π/wavelength) increases with stimulus frequency for a given membrane place, linearly at first then quadratically as the stimulus frequency approaches the best frequency (BF; Puria and Steele, 2008, The Senses). The wavenumber-frequency relationship (WFR) beyond the BF in experiments and models remains to be understood. We used finite-element models of gerbil and mouse cochleae to calculate the WFR to frequencies well above the BF. Our models replicated previous findings of the WFR increasing linearly in the long-wave region then quadratically in the short-wave region, but the relationship subsequently turned linear again near the BF region and continued this way at higher frequencies. We hypothesize that this linear increase is due to viscous damping in the cochlea which continues to dominate the response well beyond BF. There is no sign of a mass dominated region in the WFR suggesting that there is no harmonic oscillator resonance at least up to a few octaves above the BF. [Work supported by the Amelia Peabody Scholars Fund and NIDCD R01DC07910, F31DC021079, and T32 DC000038.]

Characterization of harmonic modes and parasitic resonances in multi-mode superconducting coplanar resonators

Planar superconducting microwave transmission line resonators can be operated at multiple harmonic resonance frequencies. This allows covering wide spectral regimes with high sensitivity, as it is desired, e.g., for cryogenic microwave spectroscopy. A common complication of such experiments is the presence of undesired “spurious” additional resonances, which are due to standing waves within the resonator substrate or housing box. Identifying the nature of individual resonances (“designed” vs “spurious”) can become challenging for higher frequencies or if elements with unknown material properties are included, as is common for microwave spectroscopy. Here, we discuss various experimental strategies to distinguish designed and spurious modes in coplanar superconducting resonators that are operated in a broad frequency range up to 20 GHz. These strategies include tracking resonance evolution as a function of temperature, magnetic field, and microwave power. We also demonstrate that local modification of the resonator, by applying minute amounts of dielectric or electron spin resonance-active materials, leads to characteristic signatures in the various resonance modes, depending on the local strength of the electric or magnetic microwave fields.

OA4‐AM23‐ST‐10 | Viscoelastic Testing is Paradoxically Confounded by Hematocrit in Clinical Samples Tested on Both Rotational Torsion and Harmonic Resonance Platforms

OA4‐AM23‐ST‐10 | Viscoelastic Testing is Paradoxically Confounded by Hematocrit in Clinical Samples Tested on Both Rotational Torsion and Harmonic Resonance Platforms