Electrical Spring Research Articles

A flexible load adaptive control strategy for efficient photovoltaic hydrogen generation system

The adaptive adjustment of the input current in proton exchange membrane electrolyzers (PEMEL) can provide several benefits, including the enhancement of PEMEL efficiency and the extension of its operating lifespan within an optimal range. This study presents a novel configuration for a photovoltaic (PV) hydrogen generation system that allows for the direct integration of PV. Moreover, the utilization of the triple-phase shift (TPS) modulation technique is implemented in order to achieve maximum power point tracking (MPPT) control within dual active bridge (DAB) DC/DC converters. The proposed strategy offers a pre-control approach for active adjustment of flexible loads to mitigate the mismatch between power output and load caused by fluctuations in renewable energy sources. This mismatch can lead to excessive current ripple, which in turn can impact the safe functioning of the PEMEL. In tandem with the analysis of the factors that contribute to ripple and the properties of the Electrical Spring (ES), relevant multiple variables are selected as control signals for the control strategy. This is done to effectively regulate the magnitude of non-essential loads and consequently reduce the ripple in the PEMEL system. The use of the ES pre-control technique effectively addresses the issue of delayed response of the PEMEL to PV oscillations, which is attributed to the large time-lag characteristics of electrolyzers. The simulation results at steady-state conditions and sudden changes in lighting conditions demonstrate concurrently that the overall control strategy yields a reduction in current stress in the DAB to 30.09% and 51.59%, respectively, enables MPPT in PV systems, and decreases the input current ripple of PEMEL to 80.1% and 57.67%, showing stronger anti-disturbance ability.

Single-Phase Microgrid Power Quality Enhancement Strategies: A Comprehensive Review

Renewable distributed generators (RDGs) have made inroads in recent power systems owing to the environmental effect of traditional generators and their high consumption of electric energy. The widespread use of RDGs has been a recent trend in numerous nations. The integration complexity and the intermittent nature of RDGs can undermine the security and stability of microgrids (µGs). In order to guarantee the effectiveness, dependability, and quality of the electricity delivered, appropriate control methods are necessary. RDGs are being included in single-phase microgrids (1Ø-µGs) to generate energy closer to the user. The creation of low-voltage µGs allows for increased energy efficiency and improved electrical supply dependability. Nevertheless, the combined power pumped by DGs might create power quality (PQ) difficulties, especially during off-grid operations. The three biggest problems with PQ are reactive-power swapping, voltage and frequency (VαF) variations, and current and voltage (IαV) harmonic falsification associated with 1Ø-µGs; these conditions may affect the operation of µGs. The designed and implemented (primary–secondary control systems) in RDGs are the prevalent strategy discussed in the literature for mitigating these PQ difficulties. Furthermore, emerging grid innovations like the electrical spring offer viable alternatives that might reduce some problems through decentralized operation. Although several research studies have addressed PQ concerns in 3Ø-µGs, not all of these solutions are immediately applicable to their 1Ø equivalents. In this paper, the state of the art and a performance comparison of several PQ enhancement strategies of µGs is discussed. Additionally, the primary difficulties and several PQ approach tactics are highlighted. All vital features from high-quality published articles and new dimensions in this field are presented for mitigating PQ difficulties in 1Ø-µGs.

Research on the Influence of the Closing Amount of Electrical Connector Contacts on Fretting Wear under a Vibration Environment

As a key component for transmitting electrical signals, the electrical contact performance of electrical connectors is directly affected by the closing amount of the socket. It is urgent to explore the relationship between contact resistance and the closing amount of cylindrical groove electric connectors, as well as the range of the closing amount when their comprehensive performance is optimal in vibration environments. Based on Hertz contact theory, the long- and short-axis parameters of the contact elliptical surface were obtained using the Boussinesq solution and the contact deformation coordination equation. An electrical contact resistance (ECR) theoretical model was obtained using Holm’s electric contact theory and the GW contact model. According to the ECR and long- and short-axis parameters of the contact elliptical surface and the theoretical model of contact resistance, an ECR model based on changes in the initial closing amount (deflection) of the socket spring was established by introducing the cantilever beam model of the socket spring. Then, the failure mechanism of fretting wear and the change mechanism of the ECR of the electrical connectors under a vibration environment were analyzed using the sinusoidal vibration test of electric connectors. The optimal range of the initial closing amount of the cylindrical-groove-closing-type electrical connector socket spring was determined, providing a reference for the reliability designs of electrical connectors.

Research on steady-state operation modes of electrical spring

With the help of instantaneous power theory and Matlab/Simulink simulation tools, the principle of electrical spring (ES) steady-state operation modes division was analyzed, the instantaneous power changes of ES in different steady-state operation modes were studied, then the equivalence circuit of ES under different operating conditions were deduced, the problem that how the steady-state operation mode of ES switches to stabilizes the critical load voltage with the different working conditions was analyzed. Simulation experiments verify the correctness of the research results.

Design of Single-Phase Electrical Spring Based on PR Controller and Critical Load Current Feedback

Design of Single-Phase Electrical Spring Based on PR Controller and Critical Load Current Feedback

Modelling of Electrical Spring for Voltage, Power Factor Correction and Improving Power Stability

Modelling of Electrical Spring for Voltage, Power Factor Correction and Improving Power Stability

Design Principle for Linear Electrical Machines to Minimize Power Loss in Periodic Motions

This article describes a novel approach to the design of linear machines that are not run at a steady-state operating point. The focus lies on minimizing the power loss to achieve highest possible efficiency. First analytical considerations reveal the potential of designing electrical machines and spring mechanisms for periodic, accelerated motion. It shows the influence of the machine size on the power losses due to the dependence of machine force as well as moving mass on this parameter. Based on these findings, a simulation model was created that can be used with an optimization algorithm. The simulation consists of a stationary and a time-dependent finite-element analysis of the linear machine in conjunction with an operational model that includes a given movement cycle. It was used to design a flat-type linear machine for a free-piston linear generator. The simulation results validate the analytical calculations and illustrate the differences to conventional design approaches for linear machines.

Enhance Power Quality of RES with Employing Smart Loads

In this paper investigates the improve power quality of RES with adopting smart loads in detail. In wind energy conversion system permanent magnet synchronous generator (PMSG) is employed is employed to get better simulation results over induction generators. Obtained validate MATLAB simulation results considering variable speed variations periodically. Variable wind power production needed in distribution stochastic and periodic power variations to reach load demand. This load management maintenance is highly requires to maintain power quality. This load management is allocated employing smart loads (SLs), capacitor banks and critical loads (Electrical spring).From various case studies, it is found that SLs are effective in improving the voltage profiles of the test feeder.

SH wave propagation in a piezoelectric/piezomagnetic plate with an imperfect magnetoelectroelastic interface

ABSTRACTIn this paper, we investigate the SH wave propagation in a layered piezoelectric (PE) and piezomagnetic (PM) plate with an imperfect magnetoelectroelastic interface. A linear magnetoelectroelastic spring model is used to describe the weakness of the imperfect interface. On the basis of this model, dispersion curves and mode shapes of the SH waves are computed. In particular, a PZT-5A/CoFe2O4 composite plate is considered in the numerical examples to calculate the dispersion curves and the mode shapes for different combinations of the magnetic, electrical and elastic spring constants. The effects of the layer thickness ratio and the electric-magnetic boundary conditions on the dispersion curves are discussed in details. Our results show that for a general weak bonding case, the high modes of the dispersion curves are not monotonous in the range of small wave numbers. With the layer thickness ratio increasing, the wave velocities of the SH waves increase. The electric boundary conditions mainly determine the dispersion curves of the SH waves in the case of a small layer thickness ratio, i.e. a large thickness of the PE layer. The present results have relevant applications in the nondestructive testing and evaluation of the layered PE/PM plate-like wave devices.

Review of the current challenges and methods to mitigate power quality issues in single‐phase microgrids

Distributed generation (DG) in the form of renewable energy sources is being integrated into single-phase low-voltage (LV) microgrids to produce energy closer to the consumer. The formation of LV microgrids enables to achieve high-energy efficiency and improve the reliability of the electrical supply. However, the combined power which is injected by the DG units into the grid can cause power quality issues, particularly during islanded operation. The main power quality issues related to single-phase microgrids are: reactive power exchange; voltage and frequency fluctuation; and current and voltage harmonic distortion. Amongst the methods which were identified in the literature to mitigate these issues, primary and secondary control loops implemented in the DG units themselves are the most common solution to date. Emerging grid technologies such as the electrical spring have also been proposed as alternative technologies, which could potentially mitigate certain issues through the decentralised operation. Although various research studies have been proposed concerning power quality aspects in three-phase microgrids, not all of these solutions can be applied directly to their single-phase counterparts. The aim of this study is to investigate recent developments in this area and to provide a critical review of methods to mitigate power quality issues in single-phase microgrids.

Simulation of Electrical Actuator and Air Spring Actuator Controlled Suspension Systems for Automotive Vehicles

This article discusses methods to reduce the acceleration of a vehicle and increase its road holding ability. In the simulation using quarter car model, electric actuator and air spring based actuator are used as the main control elements. A three degrees of freedom system model is used in which the parameters for the tire, vehicle body and seat are considered. The required actuator force is calculated by a standard fuzzy controller. For analysing the performance of active suspension system, body acceleration and velocity are given as inputs to the controller according to ISO specified standards. Accelerations of the seat and vehicle body are used to judge the performance of the system.

Lumped Element Modeling of a Flexible Manipulator System

This paper is concerned with a modeling method that can be used for an experimental identification of a dynamic system. More specifically, an equivalent lumped element system is presented to represent in a unique and exact manner a complete proportional-derivative (PD) controlled servo positioning system having a flexible manipulator. The impedance and mobility approach is used to transform the P and D control gains to an electrical spring and an electrical damper, respectively. The impedance model method is used to transform the flexible manipulator to a coupled system between a single contact mass at the driving position and a series of noncontact masses each of which is connected to the contact mass via a resilient member. This method is applicable whenever the driving point response of such a manipulator is available. Experimental work is presented to support the theory developed.

Optomechanical zipper cavity lasers: theoretical analysis of tuning range and stability

The design of highly wavelength tunable semiconductor laser structures is presented. The system is based on a one dimensional photonic crystal cavity consisting of two patterned, doubly-clamped nanobeams, otherwise known as a "zipper" cavity. Zipper cavities are highly dispersive with respect to the gap between nanobeams in which extremely strong radiation pressure forces exist. Schemes for controlling the zipper cavity wavelength both optically and electrically are presented. Tuning ranges as high as 75 nm are achieved for a nominal design wavelength of lambda = 1.3 microm. Sensitivity of the mechanically compliant laser structure to thermal noise is considered, and it is found that dynamic back-action of radiation pressure in the form of an optical or electrical spring can be used to stabilize the laser frequency. Fabrication of zipper cavity laser structures in GaAs material with embedded self-assembled InAs quantum dots is presented, along with measurements of photoluminescence spectroscopy of the zipper cavity modes.

Ultrasensitive mode-localized mass sensor with electrically tunable parametric sensitivity

We use the phenomena of mode localization and vibration confinement in pairs of weakly coupled, nearly identical microelectromechanical (MEMS) resonators as an ultrasensitive technique of detecting added mass on the resonator. The variations in the eigenstates for induced mass additions are studied and compared with corresponding resonant frequency shifts in pairs of MEMS resonators that are coupled electrostatically. We demonstrate that the relative shifts in the eigenstates can be over three orders of magnitude greater than those in resonant frequency for the same addition of mass. We also investigate the effects of voltage controlled electrical spring tuning on the parametric sensitivity of such sensors and demonstrate sensitivities tunable by over 400%.

Micromechanical magnetometer using an all-silicon nonlinear torsional resonator

In this work, a micromagnetometer employing a nonlinear torsional resonator with a high quality factor Q is presented experimentally. Oscillatory rotation of a conducting plate in the sensed magnetic field H induces eddy currents that dissipate energy. Due to the nonlinear response of the oscillator, the resulting mechanical damping originates frequency shifts in the resonance curve that depend on H. Nonlinearity results from the electrostatic detection, which introduces high order electrical spring constants. The device is fabricated with a standard silicon process and does not incorporate ferromagnetic materials. An analytical nonlinear model that correctly describes the device is also introduced.

MEMS variable optical attenuator using a translation motion of 45° tilted vertical mirror

A reflection-type variable optical attenuator (VOA) using the translation of a 45° tilted vertical mirror is proposed. The translation of the mirror results in an optical axis offset between transmitting and receiving optical signal, which attenuates the transmitted optical power. Single- and dual-mirror-type VOAs are implemented and compared. A conic-cladding fiber and collimating lensed fiber are applied for low insertion loss. Optical attenuation performances are predicted using the CODE V optical simulator. An electrical spring method is studied for mode separation of the mirror actuator. The self-aligned metal interlayer process is applied for achieving a notching-free mirror surface. Performances of the fabricated VOAs are measured and discussed. An attenuation range is achieved from −0.9 dB (0 V) to −35 dB (10 V). The wavelength-dependent loss (WDL) is as small as 0.4 dB even at −20 dB attenuation level. Excellent polarization-dependent loss (PDL) less than 0.24 dB is achieved in the whole attenuation range.

Reliability of low current electrical spring contacts in power modules

Reliability of low current electrical spring contacts in power modules

高電導ばね用銅合金ＭＳＰ１の開発

高電導ばね用銅合金ＭＳＰ１の開発