Under fault conditions, virtual synchronous generators (VSGs) are prone to lose transient stability, similar generators. However, the existing studies on VSG stability not comprehensive. The characteristics of VSGs highly affected by control parameters, but models in overly simplified. In addition, critical clearing angle (CCA) and time (CCT) two indices used measure a system, there few that consider both CCA CCT. this article, we analyze CCT quantitatively describe boundary under different...

In this paper, an improved control scheme is proposed to improve the voltage quality of sensitive loads using dynamic restorer. The existing strategies either put emphasis on optimal during steady operation stage compensation or correct phase angle jump in initial compensation. current researches, impact characteristic sag load side after recoveries widely ignored, further, there are still drawbacks energy self-recovery DVR. Therefore, overall time while correcting and accelerate recovery dc...

Thick barium hexaferrite [BaO⋅(Fe2O3)6] films, having the magnetoplumbite structure (i.e., Ba M), were epitaxially grown on c-axis oriented GaN/Al2O3 substrates by pulsed laser deposition followed liquid phase epitaxy. X-ray diffraction showed (0,0,2n) crystallographic alignment with pole figure analyses confirming epitaxial growth. High resolution transmission electron microscopy images revealed unit cells stacked limited interfacial mixing. Saturation magnetization, 4πMs, was measured for...

The stability of grid-connected wind power system (GCWPS) is prone to deteriorate due the impedance interaction between turbines and weak grid. For purpose finding out cause oscillation effectively improving GCWPS under grid, firstly all, a frequency coupling model (FCIM) for established. Through analyzing characteristic GCWPS, significant effect grid in middle-low region observed, which easy oscillation. restraining this paper proposes an suppression strategy based on composite feedforward...

Fault current-limiting dynamic voltage restorers (FCL-DVRs), also named as dual-functional DVRs, involving both the FCL and compensation (VC) function, have attracted more attention. However, in case of FCL-DVR operating VC mode, either high capacity storage system dc-link or oversizing power converter is needed, mode are needed. Thus, order to overcome these drawbacks, an improved FCL-DVR, which consists <italic xmlns:mml="http://www.w3.org/1998/Math/MathML"...

A strong magnetoelectric (ME) interaction is presented in a magnetostrictive-semiconductor-piezoelectric heterostructure that consists of the Huesler alloy, Co2MnAl, GaAs, and lead magnesium niobate-lead titanate (PMN-PT). The laminated Co2MnAl/GaAs/PMN-PT structure, having thickness 19 nm/180 μm/500 μm, demonstrates ferromagnetic resonance (FMR) field shift 28 Oe with an external electric 200 V across PMN-PT substrate. This corresponds to frequency ∼125 MHz at X-band. It yields large ME...

We introduce a large stroke electrostatic micro-pump made with thin PDMS diaphragm embedded thin-film metal electrodes and bonded over smoothly shaped Si substrate that acts as the counter electrode. The layer creates highly compliant diaphragm. spline-shaped height significantly reduces actuation voltage, is refined in its smoothness by modification to conventional grayscale lithography for MEMS. Combining effects of "zipper" electrode gap, displacement 100 μm achieved, giving volume 1...

Impedance-based analysis is widely used to study the stability of grid-connected inverter system in a weak grid. And characterized by ratio grid impedance(Zg)to output impedance(Zinv) However, using Zg/Zinv represent phase margin (PM) inaccurate. Meanwhile, with development adaptive control strategy, loop parameters will be adjusted dynamically change impedance, which may lead traditional impedance-based criterion(TISC) no longer applicable. In view shortcomings method, criterion...

Under weak grid conditions, the impedance and phase-locked loop (PLL) affects robust stability of grid-connected inverters, leading to harmonic resonance, or even instability in system. In this paper, a remodeling control method is proposed enhance inverters with high impedance. First, output PLL reshaped by connecting complex-coefficient filter (CCF) structure series input typical SRF-PLL. The purpose broaden range feasible phase angles that can maintain stability. Then, current reshaped,...

In this paper, an improved topology for unified power quality conditioner (UPQC) is proposed. By adding a coupling capacitor to the LC filter branch in series side of UPQC, can reduce output voltage inverter, and provide large part load-reactive power, thereby effectively reducing overall capacity dc-link level UPQC system. Because these prominent characteristics, utilization cost performance device be improved. Firstly, circuit working principle proposed are introduced. Secondly, two modes...

Ferrite phase shifter devices having drastically reduced bias field requirements are demonstrated at C and Ku band utilizing polycrystalline YIG single crystal hexagonal Y-type ferrite materials. Phase shifts on the order of 100 degrees with fields below Oe achieved. A novel numerical analysis method for modeling anisotropic ferrites is presented a good agreement between calculation results experimental data Methods generating tuning magnetic small current drives presented. The possibility...

The problem of grounding fault arc suppression is the key to safe operation distribution network, but existing voltage and current methods are difficult effectively deal with different faults. This paper proposes an adaptive regulation method considering influence line impedance. Firstly, variation residual resistance distance deduced, mechanism affected by impedance verified. Secondly, difference characteristic parameters between complete incomplete in network compared. Further, deviation...

The interior permanent magnet synchronous machine (IPMSM), which could generates reluctance torque in flux weakening region to enhance the motor performance and efficiency, is widely applied electric vehicles (EV) [1, 2]. In order dig out maximum potential of traction system EV further, dynamic DC link voltage control strategies has been explored by several researchers [3, 4]. Generally speaking, keeping a low at operating speed reduce switching losses inverter while boosting its value high...

Aiming at improving the voltage-based power quality issues and maximizing utilization of renewable generation (RG) simultaneously, this paper proposes a microgrid multifunctional dynamic voltage restorer (MFDVR). Whether grid disturbances (such as sag, swell) happen or not, MFDVR can always work by adopting vector control. Based on it, realizes full RG when normal happens, it utilize along with ensuring stability for critical loads during disturbances, both which expand function device. In...

The purpose of this work is to investigate transient aerodynamic characteristics the coach under crosswind in straight-line situations with different uniform speeds and accelerations. aerodynamics caused by speed changes are analyzed using real-time interaction between simulation dynamic simulation. target model a simplified on full scale. SST (Menter) K-Omega Improved Delayed Detached Eddy Simulation overset mesh technique used predict loads. accuracy turbulence verified wind tunnel...