The appearance of ultra-low-frequency oscillations in the grid at the sending end, after asynchronous grid interconnection, poses a significant threat to the stable operation of the system. For post-asynchronous interconnection in a multi-DC transmis...
In recent years, ultra-low-frequency oscillation (ULFO) is a prominent problem in power systems of dominant hydropower. In order to suppress ULFO, the most effective strategy is the governor parameters optimization to improve the system damping withi...
Aiming at the problem of ultra-low-frequency oscillation (ULFO) in power systems, with an oscillation frequency lower than 0.1 Hz, an oscillation suppression control method is proposed. Firstly, the mathematical modeling of the system is carried out,...
Aiming at the problem of ultra-low-frequency oscillation (ULFO) caused by an irrational setting of governor parameters of high-head hydraulic turbine units, this paper proposes a method to optimize the additional damping control parameters of the gov...
To make clear the influence of renewable energy on ultra-low-frequency oscillation (ULFO) in a hydro-dominant system via an high voltage direct current (HVDC) transmission system, this paper studies the damping characteristics when wind power is inte...
In response to the requirements of mitigating ultra-low frequency oscillation (ULFO) and enhancing primary frequency regulation (PFR) performance in hydropower-dominated systems, a novel control strategy, namely the center-frequency-structured govern...
In recent years, ultralow-frequency oscillation has repeatedly occurred in asynchronously connected regional power systems and brought serious threats to the operation of power grids. This phenomenon is mainly caused by hydropower units because of th...
In a hydropower-dominated power grid, the primary frequency regulation (PFR) capability of hydropower units is typically compromised to suppress ultra-low frequency oscillations (ULFOs). However, as renewable wind power is further integrated, a pract...
Amid the global transition toward sustainable energy, regional power grids with high wind power penetration are increasingly emerging. The implementation of frequency control is critically essential for enhancing the frequency support capability of g...
Ultra-low frequency oscillation has been regarded as a typical instability issue in power systems consisting of hydro turbine synchronous generators due to the water hammer phenomenon. However, the increasing installation of renewable power generator...
When an underwater target moves in viscous fluid, it may cause the periodic movement of the surrounding fluid and generate ultra-low-frequency (ULF) gravity waves. The initial domain of the gravitational surface wave propagating above the moving targ...
With the gradual emergence of trends such as the asynchronous interconnection of power grids and the increasing penetration of renewable energy, the issues of ultra-low-frequency oscillations and low-frequency stability in power grids have become mor...
This article reports a 110.2 MHz ultra-low-power phase-locked loop (PLL) for MEMS timing/frequency reference oscillator applications. It utilizes a 6.89 MHz MEMS-based oscillator as an input reference. An ultra-low-power, high-resolution phase-freque...
We propose a fully on-chip clock-source system in which an ultra-low-power diode-based temperature-uncompensated oscillator (OSCdiode) serves as the main clock source and frequency locks to a higher-power temperature-compensated oscillator (OSCcmp) t...
Ultra-low-frequency oscillation (ULFO) is a new problem of frequency stability in asynchronous network back-end power networks. The negative damping provided by hydropower units is the direct cause of ultra-low-frequency oscillation, and DC modulatio...
The power system’s dynamic frequency stability is affected by common-mode ultra-low-frequency oscillation and differential-mode low-frequency oscillation. Traditional frequency control based on generators is facing the problem of capacity reduc...
This article presents a 6.89 MHz MEMS oscillator based on an ultra-low-power, low-noise, tunable gain/duty-cycle transimpedance amplifier (TIA) and a bulk Lamé-mode MEMS resonator that has a quality factor (Q) of 3.24 × 106. Self-cascoding and curren...
The paper discusses a way to configure a stepped-frequency continuous wave (SFCW) radar using a low-cost software-defined radio (SDR). The most of high-end SDRs offer multiple transmitter (TX) and receiver (RX) channels, one of which can be used as t...
The growing demand for low-frequency, broadband vibration and noise suppression technologies in next-generation mechanical equipment has become increasingly urgent. Effective negative mass locally resonant structures represent one of the most paradig...
Measurements monitoring the inductive coupling between oscillating radio-frequency magnetic fields and objects of interest create versatile platforms for non-destructive testing. The benefits of ultra-low-frequency measurements, i.e., below 3 kHz, ar...
Due to their lack of pollution and long replacement cycles, piezoelectric energy harvesters have gained increasing attention as emerging power generation devices. However, achieving effective energy harvesting in ultra-low-frequency (<1 Hz) rotati...
An optoelectronic oscillator (OEO) is an optoelectronic hybrid oscillator which utilizes ultra-low-loss fiber as an electro-magnetic energy storage element, overcoming the limits of traditional microwave oscillators in phase noise performance. Due to...
This work presents a current-controlled CMOS ring oscillator (CCRO) optimized for ultra-low-voltage applications in next-generation energy-constrained systems. Leveraging bulk voltage tuning in 22 nm FDSOI differential inverter stages, the topology e...
Optical parametric oscillation can convert the input laser into a couple of coherent optical output with signal and idler frequencies. It is an important method for the realization of the broadband middle infrared tunable lasers. The optical parametr...
A considerable amount of ambient vibration energy spreads over an ultra-low frequency spectrum. However, conventional resonant-type linear energy harvesters usually operate within high and narrow frequency bands, which cannot match the frequencies of...
Mechanical properties of metallic-nanowire self-oscillations are investigated through a coherent-state analysis. We focus on elucidating the time behavior of quantum energy in such oscillations, in addition to the analysis of fluctuations, evolution...
This paper investigated the optimization of the hardness and oscillation mode of flexible hydrofoils using bidirectional fluid–structure interaction (FSI) to address the issue of insufficient guidance in engineering applications. A two-dimensio...
This paper proposes a novel operational amplifier (OPA) voltage-controlled oscillator (VCO) circuits on the basis of impedance converters. The VCO can operate over a frequency range exceeding unity-gain bandwidth due to the location of the tank circu...
This article presents a low power digital controlled oscillator (DCO) with an ultra low power duty cycle correction (DCC) scheme. The DCO with the complementary cross-coupled topology uses the controllable tail resistor to improve the tail current ef...
In this paper, a novel microwave photonic filter (MPF) based on a single longitudinal mode Brillouin laser achieved by parity time (PT) symmetry mode selection is proposed, and its unparalleled ultra-narrow bandwidth as low as to sub-kHz together wit...
Accurately estimating the modulation parameters of pseudorandom binary code–pulse amplitude modulation (PRBC–PAM) signals damaged by strong noise poses a significant challenge in emitter identification and countermeasure. Traditionally, w...
Towards the integration of Digital-LDO regulators in the ultra-low-power System-On-Chip Internet-of-Things architecture, the D-LDO architecture should constitute the main regulator for powering digital and mixed-signal loads including the SoC system...
In this paper, an optoelectronic oscillator (OEO) with ultra-low phase noise and high stability based on the injection-locked and phase-locked loop is proposed. In theory, the injection-locked frequency range of the injection signal is studied based...
A fully-integrated switched-capacitor (SC) DC-DC converter that steps down 2.0 V to 0.9 V with a peak efficiency of 80% is implemented in a 0.18 μ m CMOS process. An ultra-low-power voltage-controlled oscillator that generates a wide range of...
Very low frequency (VLF) signals are considered as an important tool to study ionosphere disturbances. We have studied variations in signal amplitude of the Japanese JJI transmitter received by a network of eight Japan stations. The distinctions betw...
A passive harmonic tag for buried assets localization is presented for utility localization. The tag design is based on a dual-polarized patch antenna at Ultra High Frequency (UHF) band. One of its feeders is connected to a frequency doubler based on...
In the context of the plain river network, conventional water pumps suffer several drawbacks, including inadequate efficiency, poor security, and costly installation costs. In order to improve the hydrodynamic insufficiency problem and enhance the hy...
The high precision and low power consumption of the clock generator are critical in passive RFID transponders and passive IoT chips, but fluctuations in PVT can cause considerable degradation in the precision of the chip’s internal clocks. This...
An image-rejected multi-band frequency down-conversion scheme is proposed and experimentally demonstrated based on photonic sampling. The multi-band radio-frequency (RF) signals to be processed are copied into two replicas in quadrature, which are th...
In the present study, a new structure (0.5–18 GHz) with excellent phase noise characteristics and a fast switching speed is proposed. Ultra-wideband synthesizers with low phase noises and less spurious signals have been developed to be used as...
This study delves into the dynamic behavior of ultra-high-speed rotor systems underpinned by helium hydrostatic gas bearings, with a focus on the impact of rotational velocity on system performance. We have formulated an integrative dynamic model tha...
Current trends towards on-edge computing on smart portable devices requires ultra-low power circuits to be able to make feature extraction and classification tasks of patterns. This manuscript proposes a novel approach for feature extraction operatio...
The article describes a hard- and software controlled complex for gas-strain monitoring, consisting of stationary laser strainmeters and a laser nanobarograph, a stationary gas analyzer, and a weather station installed at Shultz Cape in the Sea of Ja...
A miniature sensor and control system is developed to facilitate human eye ciliary muscle movement detection and to drive the corresponding liquid crystal based lens to create an autofocusing lens for cataract patients. The movement of the ciliary mu...
Using stochastics in stock market analysis is widely accepted for index estimation and ultra-high-frequency trading. However, previous studies linking index estimation to actual trading without applying low-frequency trading are limited. This study a...
This paper proposes a review of several circuits for communication and wireless sensing applications implemented on cellulose-based materials. These circuits have been developed during the last years exploiting the adhesive copper laminate method. Su...
Kinetic piezoelectric energy harvesters are used to power up ultra-low power devices without batteries as an alternative and eco-friendly source of energy. This paper deals with a novel design of a lead-free multilayer energy harvester based on BaTiO...
Optoelectronic oscillators (OEOs) have emerged as indispensable tools for generating low-phase-noise microwave and millimeter-wave signals, which are critical for a variety of high-performance applications. These include radar systems, satellite link...
Primary frequency regulation (PFR) is a crucial operating condition for PSPs to realise frequency modulation, and the effectiveness of PFR is significant to the stability of power system frequency. Several challenges and risks have been presented in...
Recent research in algorithmic trading has primarily focused on ultra-high-frequency strategies and index estimation. In response to the need for a low-frequency, real-world trading model, we developed an enhanced algorithm that builds on existing mo...
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