Resonance Suppression Research Articles

Harmonic Resonance Suppression With Inductive Power Filtering Method: Case Study of Large- Scale Photovoltaic Plant in China

Taking actual engineering as a case study, this article provides a novel scheme of applying the inductive power filtering method (IPFM) to resolve the harmonic resonance issues in large-scale photovoltaic (PV) plant. By using IPFM's special structure and dual zero-impedance design, the impedance network of large-scale PV plant is reshaped while the performance of power filters is improved, so that the harmonic resonance due to the interaction between the inverters and the power grid is suppressed. First, the topology and components of the IPFM-based large-scale PV plant are introduced. The three-phase mathematical model in harmonic domain is then established. Based on the deduced transfer matrix, the simplified circuit of the studied large-scale PV plant is obtain-ed. Moreover, the IPFM's resonance damping mechanisms on resonant frequency shift and harmonic amplification mitigation are analyzed. Both simulation and engineering tests verify the feasibility of the proposal.

Hybrid Frame-Based Current Control Scheme for LC-Equipped PMSM With Non-Sinusoidal Back-EMF

Permanent-magnet synchronous machine (PMSM) drive with a sine wave <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> filter has the features of low insulation stress and current harmonics. However, few studies consider the impact of back-electromotive force (EMF) harmonics on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> -equipped PMSM drive system. The non-sinusoidal back-EMF can cause current harmonics, meanwhile, it also affects the stability analysis and high-frequency resonance suppression. In order to solve these two problems simultaneously, a hybrid frame-based current control scheme is proposed in this paper. The quantitative effect of back-EMF harmonics on control behaviors is analyzed first. A virtual triple three-phase system with auxiliary currents is developed to decompose the fundamental and harmonic contents, which not only contributes to independent current harmonic regulation in multiple synchronous reference frames, but also simplifies system stability analysis considering non-sinusoidal back-EMF. Then, an active damping method based on stator current feedback is implemented in the stationary frame to suppress the resonance, and no additional passive components or sensors are required. Finally, experimental results are provided to verify the effectiveness and superiority of the proposed method.

Catalytic degradation of dimethomorph by nitrogen-doped rice husk biochar

N-doped biochar is widely used for activating persulfate to degrade organic pollutants. Which type of N atom is the key factor for activation is still unclear and needs to be further explored and analyzed. In this study, four kinds of biochar were prepared using urea and rice husk as precursors, and tested for the catalytic degradation of dimethomorph. Increasing the nitrogen doping level caused the catalytic removal efficiency of dimethomorph in the presence of peroxymonosulfate increased from 16.6% to 86.8%. A correlation analysis showed that the ability of N-doped biochar to activate PMS is mainly related to the content of pyrrole N, graphite N and carbonyl and the degree of defects. In experiments on electron paramagnetic resonance and free radical suppression, the reactive species of SO4•-, 1O2,·OH and O2.− were detected, among which 1O2 was found to be the main agent in the nonradical pathway. The degradation pathways for dimethomorph were analyzed based on a total of 8 degradation products identified by high-performance liquid chromatography-time of flight mass spectrometry (HPLC-Q-TOFMS). The results of this study provide a fundamental basis for using agricultural waste to produce inexpensive and efficient nonmetal catalysts that are highly effective in reducing dimethomorph levels in agricultural lands.

Identification Algorithm and Improvement of Modal Damping Ratios for Armature Assembly in a Hydraulic Servo-Valve with Magnetic Fluid

The high-frequency vibration and resonance of armature assembly in the hydraulic servo valve are the main reasons for instability and failure. Magnetic fluid (MF) operating in the squeeze mode can be taken as an effective damper for resonance suppression in the servo valve. Due to excitation difficulty and the low signal-to-noise ratio of high-frequency vibration signals, the capability of MF to modify multiple-order modal damping ratios in a multi-degree-of-freedom system is still unclear. To reveal the mechanism of magnetic fluid for improving modal damping ratios, an algorithm for modal damping ratio identification is proposed. The modal damping ratios of the armature assembly with and without magnetic fluid are identified based on the tested resonance free decay responses. Four resonance frequencies of armature assembly are observed, and the corresponding damping ratios are identified. The equivalent modal damping ratios due to squeeze flow of MF are obtained. The results show that the proposed algorithm can identify damping ratios with an accuracy of up to 98.79%. The damping ratios are improved by double or more due to the magnetic fluid, and the maximum resonance amplitudes are significantly reduced by 65.2% (from 916.5 μm to 318.6 μm).

Photoinduced structural transformations of Au-As2S3 nanocomposite impregnated in silica porous glass matrix

This article investigates the photoinduced changes (PICs) in the optical properties of As2S3 impregnated in porous glasses (PGs) and the influence of gold nanoparticles (AuNPs). The composite material was obtained via a simple chemical deposition method where As2S3 powder was dissolved in an amine solution and impregnated into PG pieces, with and without the addition of AuNPs. Using Fourier-transform infrared spectroscopy, it was confirmed that, when mixing solutions of As2S3 and AuNPs they interact and form complexes that result in the plasmonic resonance suppression of AuNPs. Upon irradiation using green laser (532 nm) a significant increase in the bandgap energies of the samples was observed. This effect was studied using Raman spectroscopy. Moreover, it was noticed that the change in the bandgap energy depends on the As2S3 concentration and is reduced by the presence of AuNPs.

Current Control Scheme for LC-Equipped PMSM Drive Considering Decoupling and Resonance Suppression in Synchronous Complex-Vector Frame

Permanent-magnet synchronous machine drive with sine wave filter has features of low insulation stress and current harmonics. However, the filter can affect the current control of machine. Specifically, the increased axes cross-coupling degrades the response performance in the transient state, and the introduced resonant frequency oscillations can make the system unstable. To solve the issues, a complex-vector frequency-domain model of LC -equipped permanent-magnet synchronous machine drive is established in this article. Moreover, a quantitative index related to the symmetrical extent of double-sided frequency responses is introduced to evaluate the performance. A decoupling strategy based on the modified complex-vector controller is proposed and compared against conventional methods in terms of decoupling performance and parameter robustness based on the aforementioned evaluation index. Furthermore, an active damping method based on virtual impedance in parallel with the stator inductance is proposed to suppress the resonance. The quantified double-sided frequency-domain analysis is performed to illustrate the relationship between cross-coupling and system stability. Then, the systematic codesign procedure of decoupling controller and active damping link in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$z$ </tex-math></inline-formula> -domain is proposed. Finally, the experimental results show that the proposed scheme can improve the overall control performance in both transient and steady states.

High Frequency Resonance Analysis and Resonance Suppression of a Grid-Connected Inverter Coupled With a Long Feeder

With the development of distributed generation (DG) technologies, various inverter-interfaced DG systems have been connected to the grid, which can cause serious harmonic issues. For an inverter-interfaced DG source connected to the grid via a long feeder, multiple resonances may occur due to the non-negligible distributed capacitance of the long line. Multiple resonances can cause current distortions when the DG delivers power to the grid and the harmonic voltage may be amplified because of the resonances. Many inverter control strategies have been studied, but few can suppress harmonics. To solve this issue, this paper derives the voltage transmission equations to analyze the transmission characteristics of harmonic voltages along a long feeder and reveals the reasons for the multiple resonances in the current. Based on the transmission line theory, a new control strategy of inverter is proposed to suppress the multiple resonances in current and the amplification of harmonic voltages. Finally, the effectiveness of the proposed control strategy is verified by the simulation and experimental studies.

Robust Subsynchronous Damping Control of PMSG-Based Wind Farm

This paper provides an H∞ robust control strategy for a permanent magnet synchronous generator (PMSG)-based wind farm to realize subsynchronous resonance suppression (SSR) subject to uncertain system distortions and parameter perturbation. Firstly, an eighth-order state space mathematical model of a PMSG-based wind farm is established, including the grid-side converter (GSC), GSC controller, and phase-locked loop (PLL) model. Secondly, the SSR characteristics of a PMSG-based wind farm are analyzed through eigenvalue analysis. Thirdly, a robust subsynchronous damping controller is designed based on eigenvalue analysis of SSR. Finally, the designed robust subsynchronous damping controller is validated with case studies of wind farms. The results show that the controller can increase the stability of PMSG-based wind farm systems and restrain SSR.

A LCCR filter based harmonic suppression method for power quality improvement

As power converters have been widely used in renewable energy generation and motor drive system for the industrial production, the harmonics of output voltage of power converter will seriously affect the system power quality. To improve power quality of the converter, passive filters such as L-type filters, LC-type filters and LCL filters can are used, which have large volume and poor performance under certain conditions. Aiming at reducing the output harmonic characteristics of PWM power converter, this paper analyzes the frequency characteristics of LCCR filter and proposes a new parameterized model of LCCR filter. Based on the parameterized model of LCCR filter, a high-precision parametric design method of LCCR filter with resonance suppression is also presented in this paper. The frequency characteristics of LCCR filter are designed by a set of four-element methods with frequency characteristic parameters, which can eliminate the coupling relationship between the parameters. The frequency characteristics of the LCCR filter can be directly reflected by the defined parameter. The parameterized design method of LCCR filter presented in this paper can reduces the complexity of multi-parameter LCCR filter design, effectively improves the accuracy and rapidity of filter design. Both the analytical and experimental results validate that the LCCR filter can be accurately designed to suppress the harmonics caused by power converters.

AC impedance model and resonance suppression method of multilevel converter

Under the “carbon peaking and carbon neutrality” goal, the long-distance transmission of clean energy can play an important role, and VSC-HVDC (Voltage Source Converter based High Voltage Direct Current ) transmission system is one of the main means for new energy to be connected to the AC system. The stability problem caused by the large-capacity VSC-HVDC connected to the AC system has attracted much attention. In this regard, for the oscillation problem between the converter and the AC system that appears in the actual VSC-HVDC project, the mechanism of system oscillation is analysed, and the resonance suppression method is proposed. First, a mathematical model of the converter impedance was established. The impedance model was derived in real and complex form, simplifying the tedious trigonometric function operation and derivation process. The model considers the impact of key factors such as AC cables and system delays in actual projects. The correctness of the model was verified by the impedance scanning method. Secondly, the series resonance and parallel resonance characteristics of the system were analysed, for improve the impedance characteristics of the system at the resonance point to ensure the stability of the system, the engineering design method of the compensation link based on a proportional-resonant regulator was proposed. Finally, simulation verification of the proposed control strategy based on PSCAD software was performed for proving its correctness and effectiveness.

Analysis of impedance characteristics and resonance suppression strategies of VSC-HVDC system using grid-forming control

Grid-forming control can effectively improve the power transmission capacity and stability of the voltage source converter based high voltage direct current (VSC-HVDC) transmission system under the weak power grid condition. However, there was no related research on the mid- and high-frequency impedance characteristics and resonance stability of the VSC-HVDC system using grid-forming control. In this article, the mathematical model of positive and negative sequence impedance of VSC-HVDC system using grid-forming control was established. The influence of the control system parameters and the delay time of control system on the impedance characteristics was analyzed. It was found that the power-synchronization loop (PSL) has little effect on the impedance in the mid- and high-frequency bands, and the impedance amplitude has resonant peaks under certain conditions. Resonance suppression strategies under grid-forming control were proposed, including optimizing parameters of the control system, adding low-pass filters and reducing the delay time of control system. An electromagnetic transient simulation model of VSC-HVDC system under grid-forming control was built to verify the correctness of theoretical analysis.

Theory of Truncation Resonances in Continuum Rod‐Based Phononic Crystals with Generally Asymmetric Unit Cells (Adv. Theory Simul. 2/2023)

Resonant modes emerging within bandgaps, or truncation resonances, represent a unique phenomenon of phononic materials and play a central role in flow control, edge/surface modes and sensing applications. In article 2200700, Mostafa Nouh and co-workers establish the fundamental factors that contribute to the origination or suppression of truncation resonances and provides an interpretation of localized vibrational modes in finite phononic crystals.

Ultrafast Modulation of THz Waves Based on MoTe2-Covered Metasurface.

The sixth generation (6G) communication will use the terahertz (THz) frequency band, which requires flexible regulation of THz waves. For the conventional metallic metasurface, its electromagnetic properties are hard to be changed once after being fabricated. To enrich the modulation of THz waves, we report an all-optically controlled reconfigurable electromagnetically induced transparency (EIT) effect in the hybrid metasurface integrated with a 10-nm thick MoTe2 film. The experimental results demonstrate that under the excitation of the 800 nm femtosecond laser pulse with pump fluence of 3200 μJ/cm2, the modulation depth of THz transmission amplitude at the EIT window can reach 77%. Moreover, a group delay variation up to 4.6 ps is observed to indicate an actively tunable slow light behavior. The suppression and recovery of the EIT resonance can be accomplished within sub-nanoseconds, enabling an ultrafast THz photo-switching and providing a promising candidate for the on-chip devices of the upcoming 6G communication.

Traction transformer integrated LCL filtering method for high-frequency harmonic and resonance suppression in AC train

Converters in AC-DC-AC traction drive system introduce a wide range of high-frequency harmonics. When the high-frequency harmonics contain contents at around the inherent resonance frequency of the traction power supply system, it will cause harmonic resonance in the traction grid. The LCL-type single phase line-side converter is widely adopted to prevent the high-frequency harmonics from entering the traction grid. However, additional four inductors and four capacitors are needed to form the filtering system, which increases the occupied onboard space. In this paper, a traction transformer integrated LCL filtering method is proposed to achieve high-frequency harmonic and resonance suppression and, at the same time, reduce the space occupied by the LCL filter. The equivalent circuit of the traction transformer integrated LCL filtering system is modeled and the mechanism of harmonic and resonance suppression is analyzed. Then, the required equivalent impedances of the traction transformer, the filtering capacitor, and the corresponding controller of line-side converter are designed. Finally, the parameter design of the traction transformer prototype is verified by finite element simulation. And the grid-train system with the traditional L filter, LCL filter, and the proposed traction transformer integrated LCL filter are simulated by real-time field-circuit coupling simulation, which verifies the good filtering effect of the proposed method.

Analytical investigation on piezoelectric shunting circuit for resonance suppression of the nonlinear vibration system

Analytical investigation on piezoelectric shunting circuit for resonance suppression of the nonlinear vibration system

A pH/GSH dual responsive nanoparticle with relaxivity amplification for magnetic resonance imaging and suppression of tumors and metastases.

Engineered magnetic nanoparticles combining diagnosis and therapy functions into one entity hold great potential to rejuvenate cancer treatment; however, they are still constrained by the "always on" signals and unsatisfactory therapeutic effect. Here, we report an intelligent theranostic probe based on Mn3O4 tetragonal bipyramids (MnTBs), which simultaneously respond to H+ and glutathione (GSH) with high sensitivity and quickly decompose to release Mn2+ in mild acidic and reductive intracellular environments. Mn2+ binds to the surrounding proteins to achieve a remarkable relaxivity amplification and selectively brighten the tumors. Particularly, this MR signal improvement is also effective in the detection of millimeter-sized liver metastases, with an ultrahigh contrast of 316%. Moreover, Mn2+ would trigger chemodynamic therapy (CDT) by exerting the Fenton-like activity to generate ˙OH from H2O2. Subsequently, a significant tumor suppression effect can be achieved by the GSH depletion-enhanced CDT. Besides, MnTBs manifest efficient urinary and hepatic excretions with biodegradability and minimal systemic toxicity. A pH/GSH dual responsive nanoprobe that integrates tumor diagnostic and therapeutic activities was developed to provide a new paradigm for precise diagnosis and treatment of tumors and metastases.

Harmonic Resonance Suppression Strategy of the Front-End Vienna Rectifier in EV Charging Piles

Owing to the distributed installation position, the electric vehicle (EV) charging pile is usually connected to the grid via transmission cables of different lengths. The resonance of parasitic inductance and parasitic capacitance on the transmission cables might amplify the background harmonics, which result in a serious distortion of the grid-connected current of the front-end Vienna rectifier of EV charging piles. To overcome the resonance issue, this article proposes a harmonic resonance suppression strategy of the Vienna rectifier, which reshapes the closed-loop input harmonic impedance of the Vienna rectifier to be close to the characteristic impedance of the transmission cable by optimizing the traditional dual closed-loop control strategy of the Vienna rectifier based on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> coordinate frame. The proposed suppression strategy can not only ensure the low ripple output voltage of the Vienna rectifier, but also suppress the background harmonic resonance amplification; thus, the power quality of the Vienna rectifier grid-connected current and the voltage at the point of common coupling will be improved effectively. Both the simulation and experimental results verify the effectiveness and correctness of the proposed strategy.

Resonance Suppression of High-temperature Superconducting Magnetic Levitation Systems

Resonance Suppression of High-temperature Superconducting Magnetic Levitation Systems

Recognition of Electrical Control System of Flexible Manipulator Based on Transfer Function Estimation Method

Abstract This article proposes a resonance suppression method for a flexible load servo drive system based on a flexible manipulator's pose transformation. We establish a flexible load servo drive system for the robotic arm based on the continuum vibration theory and the transfer function estimation method. The controller consists of two parts: compensation control and dynamic feedback. The transfer function of the active feedback part is strictly positive and real. At the end of the thesis, the asymptotic stability of the closed-loop system in the neighborhood of the desired position is proved through the linear operator semigroup theory and the LaSalle invariant set principle.

Nonlinear resonance suppression method of 3D contact probe based on dynamic TSVD inversion

High-precision measurement of 3D probe is usually inseparable from the quasi-static measurement model. However, insufficient dynamic characteristics and uncertainty of the measured characteristics make the measurement results inevitably affected by the resonance nonlinear factors in dynamic measurement. This paper proposes a nonlinear suppression method of dynamic resonance based on truncated singular value decomposition (TSVD) inversion. The dynamic time-domain response function based on the transfer function of the probe system is constructed, and the basic characteristics of nonlinear resonance response and the causes of error are revealed. Then, a piezoelectric positioning system is used to generate a wide-band dynamic excitation signal, and dynamic broadband response signals with linear and nonlinear comprehensive characteristics is inversed with high accuracy through the dynamic measurement experiment. By comparing with typical measurement methods, the advantages of the proposed method in improving dynamic measurement accuracy and suppressing resonance nonlinearity are quantitatively verified.