Charge Feedback Control Research Articles

Taguchi robust design for adaptive energy management of plug-in fuel cell electric bus

This paper presents an adaptive energy management strategy (EMS) based on Pontryagin's Minimum Principle (PMP), considering both historical driving cycles and stochastic vehicle mass. First, an improved battery state of charge (SOC) feedback control method based on Proportion-Integration (PI) controller is proposed for adaptive energy management. Second, a Taguchi robust design (TRD) method is proposed by considering the noises of historical driving cycles and stochastic vehicle mass. The main purpose of the TRD is to find the robust parameters (P and I) that can counter to the above noise disturbance, thereby neglecting the influence of noise disturbance in adaptive energy management control and minimizing the mean hydrogen consumption. The results show that the TRD is reasonable and applicable in the robust design of plug-in fuel cell electric buses (PFCEBs); the fuel economy of the proposed strategy can be averagely improved by 18.36%, compared to the rule-based energy management strategy.

Moving Regression Filtering With Battery State of Charge Feedback Control for Solar PV Firming and Ramp Rate Curtailment

The surge in energy demand needs to be met with environmentally pleasant resources to reduce the production of greenhouse gases. Solar Photovoltaic (PV) power is a widespread choice as it is accessible in plenty and is comparatively inexpensive. However, the large-scale penetration of intermittent PV power causes multiple variabilities in the grid such as frequency issues and voltage deviations. To counteract these instabilities, Battery Energy Storage System (BESS) is integrated into the grid as it reduces the PV fluctuations and promotes optimal operation. Nevertheless, storage systems are expensive, and thus smoothing filters are coupled with the BESS for cost reduction and power smoothing. Formerly, traditional filters such as Low Pass Filters (LPF), Moving Average (MA), and Moving Median (MM) filters have been proposed for power smoothing. However, these filters have inadequate power tracking capabilities particularly with longer window sizes (W.S) and time constants, which subsequently depreciates the storage system performance. To compensate for the delayed power tracking, larger energy storage systems are required which in turn adds to the overall operational costs. This paper proposes the Moving Regression (MR) filter combined with state of charge (SoC) feedback control for solar PV variability reduction, reduced time delay, decreased battery charging/discharging power, and ramp rate. Simulation results attest that the MR filter achieves better solar power smoothing without increasing the BESS capacity. Also, the performance of the MR filter is less affected with the increase in window sizes. Additionally, the execution of the introduced smoothing filter was found to be superior when assessed against the LPF, MA, MM, Savitsky-Golay (SG), and the Gaussian filter. In comparison to the SG (W.S = 53), the MR (W.S = 45) filter reduces the battery charging/discharging power by approximately 30.48% and as opposed to the LPF (T.C = 48), the peak SoC is reduced by 19.1%.

Adaptation‐Enhanced Model‐Based Control with Charge Feedback for Piezo‐Actuated Stage

AbstractThis paper proposes a new control design to compensate for the residual control error from charge feedback control. A part of the applied voltage is consumed by the hysteresis effect because of the nature of the piezoelectric material; moreover, this effect is difficult to overcome because it is rate dependent. This work utilizes a piezoelectric electromechanical model to propose a precompensation algorithm for a piezoelectric actuator. A nonlinear compensator can be used to treat both the hysteresis nonlinearity and the rate dependency of the system, and the adjustable parameters are specified through adaptive identification with only basic system information. The proposed design can position a piezoelectric stage with a magnifying mechanism within a few nanometers of a target, and the leftover hysteresis phenomenon is negligible.

Compensation of the residual error from the charge feedback control of a piezoelectric-actuated stage

Charge control for a piezoelectric actuator is supposedly unaffected by the hysteresis effect; however, the voltage applied to the actuator covers both the effective force-generating voltage and the hysteresis voltage. In this article, this hysteresis nonlinearity is considered an extra disturbance over a linear system. A novel approach entailing the use of the parasitic capacitance charge feedback in conjunction with a Preisach model to estimate the hysteresis disturbance is proposed. The estimated extra voltage enables the controller to augment its effort with an additional term to compensate for this loss. The article also describes the establishment of an adequate Preisach model. The proposed approach applies a low-pass filter and feedforward compensator to improve the tracking performance. Control results under sinusoidal reference and staircase reference tracking confirmed the effectiveness of the proposed compensation in eliminating the hysteresis effect and achieving high-precision control.

SoC Feedback Control for Wind and ESS Hybrid Power System Frequency Regulation

With increased penetration of wind generation, the traditional control scheme of the wind turbine (WT), which is designed for maximum wind power extraction, is no longer suitable to meet emerging grid requirements for wind farms to participate in frequency regulation. The control scheme of the WT with respect to grid frequency regulation is proposed in many studies, such as those on pitch control. Also, energy storage technologies have drawn much attention in recent years because, as technology matures and costs decrease, they present themselves as a potential solution for the challenge brought about by the uncertainty of renewable energy generation with regard to power system stability. A power system consisting of a high penetration of wind generation and energy storage systems (ESS) is investigated in this paper for the regulation of grid frequency. A new strategy called state of charge (SoC) feedback control is proposed, and the performance of the grid frequency deviation response and the SoC of the battery are presented. The model of the power system studied in this paper is established on the MATLAB/SIMULINK platform.

Precision tracking of a piezo-driven stage by charge feedback control

Abstract This paper presents a novel approach for precisely controlling the motion of a piezo actuator embedded in a mechanical stage without using a displacement sensor. A piezo actuator has a high displacement resolution, but the positioning performance is degraded by hysteresis between the applied voltage and resultant displacement. However, an electromechanical model of a piezo actuator suggests that the charge flowing in the actuator is directly related to the dynamic response of the piezo displacement. Therefore, this study directly measured the charge stored in a piezo actuator, and achieved dynamic reference tracking of the actuator's displacement by regulating the charge flowing through the actuator to follow a predefined trajectory. This novel approach requires neither specially designed charge amplifier circuits nor implementation of an inverse hysteresis model. The complete model identification and the digital controller design procedure for a piezo-driven mechanical stage are presented. The charge feedback controller is designed according to the dynamic characteristics of both the actuator and the stage, so that instability is minimized relative to using a charge amplifier. The experimental results confirm satisfactory tracking performance, and reveal the influence of model uncertainties on the system performance.

Active Acoustic Metamaterial With Simultaneously Programmable Density and Bulk Modulus

Acoustic metamaterials are those structurally engineered materials that are composed of periodic cells designed in such a fashion to yield specific material properties (density and bulk modulus) that would affect the wave propagation pattern within in a specific way. All the currently exerted efforts are focused on studying passive metamaterials with fixed material properties. In this paper, the emphasis is placed on the development of a new class of composite one-dimensional active acoustic metamaterials (CAAMM) with effective densities and bulk moduli that are programmed to vary according to any prescribed patterns along its volume. A cylindrical water-filled cylinder coupled to two piezoelectric elements form a composite cell to act as a base unit for a periodic metamaterial structure. Two different configurations are considered. In the first configuration, a piezoelectric panel is flash-mounted to the face of the cylinder, while the other is side-mounted to the cylinder wall, introducing a variable stiffness along the wave propagation path. In the second configuration, the face-mounted piezoelectric panel remains unchanged, while the side-mounted panel is replaced with an active Helmholtz resonator with piezoelectric base panel. A detailed theoretical lumped-parameter model for the two configurations is present, from which the stiffness of both active elements is controlled via charge feedback control to yield arbitrary homogenized effective bulk modulus and density over a very wide frequency range. Numerical examples are presented to demonstrate the performance characteristics of the proposed. The CAAMM presents a viable approach to the development of effective domains with a controllable wave propagation pattern to suit many applications.

An Optimal State of Charge Feedback Control Strategy for Battery Energy Storage in Hourly Dispatch of PV Sources

Abstract The effects of intermittent cloud and changes in temperature cause a randomly fluctuated output of a photovoltaic (PV) system. To mitigate the PV impacts particularly on a weak electricity network, battery energy storage (BES) system is an effective means to smooth out the power fluctuations. Consequently, the net power injected to the electricity grid by PV/BES systems can be dispatched smoothly such as on an hourly basis. This paper presents an improved control strategy for a grid-connected BES for mitigating PV farm output power fluctuations. A feedback controller for state of charge is proposed where the control parameters are optimized using genetic algorithm. In this way, the optimal size for the BES is also determined to hourly dispatch a 1.2 MW PV farm. The effectiveness of the proposed control scheme is evaluated using PSCAD/EMTDC-based simulation.

Nonlinear Charge Control for a Collinear Fixed-Shape Three-Craft Equilibrium

The collinear equilibrium three-craft-formation charge feedback control problem is investigated. Given a charged-equilibrium collinear configuration of spacecraft flying in deep space, a nonlinear charge feedback control algorithm is developed to stabilize the formation to the desired shape and size. The Coulomb forces are assumed to be acting along the line-of-sight directions between the bodies and thus do not provide general vehicle position controllability. A study of the charged collinear three-craft formation shows that there exists an infinite number of equilibrium charge solutions for any collinear configuration. Given a real value of one spacecraft charge, the required equilibrium charges of the remaining two vehicles are solved analytically. A Lyapunov-based nonlinear control algorithm is developed to stabilize the configuration to the equilibrium state using only the spacecraft charges as the control states. Real charge solutions are ensured by using the one-dimensional solution null-space. Numerical simulations illustrate the new charge feedback control performance. In contrast to earlier efforts, collinear configurations are stabilized even in the presence of very large initial position errors.

A Charge Feedback Controller for a Piezoelectric Voltage Amplifier/Driver

AbstractIn this paper, authors examine the design and implementation of a new charge feedback control circuitry for a voltage amplifier used in driving of a piezoelectric actuator. Actuators driven in the usual voltage feedback regime display a nonlinear voltage-displacement relationship, known as hysteresis. Use of the new charge feedback control circuitry resulted in significant reduction (70%) of the hysteresis-related nonlinearity.

誘導電荷のフィードバックによる圧電素子の変位制御 （第２報） パラレルメカニズム制御への適用

This paper deals with an stage for a scanning probe microscope (SPM) by using a Stewart platform type parallel mechanism with 6 degrees of freedom. Stacked piezoelectric actuators are used to change link length in a prototype. The movable range of the prototype is 100μ in the x and y directions and 201tm in the z direction. The resonant frequency of the prototype is 100 Hz in the x and y direction and 75 Hz in the z direction approximately. The table motion is controlled by the induced charge feedback control to allow compact SPM designs. The motion error is 16 nm in the z direction by the induced charge feedback control. The displacement of the prototype can be controlled by the induced charge feedback control as well as by the displacement feedback control. This stage is applied to a positioning device of an atomic force microscope (AFM). The grooves of a diffraction grating are observed with good linearity. The prototype can be used for the positioning device of the AFM.

Piezoelectric Stack Actuators and Control System Design: Strategies and Pitfalls

An evaluation is presented of two control strategies for piezoelectric stack actuators: voltage feedback control and charge feedback control. The study consists of two principal parts: an experimental determination of the nonlinearities inherent in piezoelectric actuators using different control strategies and an analysis of how those nonlinearities would affect the stability and performance of feedback control systems that utilize piezoelectric actuators. The voltage control responseof thepiezoelectricactuator tested wasdemonstrably more nonlinear than thesameactuatorwithchargefeedback circuitry. Nyquistdesign analysisrevealsthatthesenonlinearitiestranslate into lower stability margins and potential system performance for voltage control of piezoelectric actuators as compared to charge control. The improved system stability that can be achieved with charge control as compared to voltage control is demonstrated to be signie cant in multi-degree-of-freedom systems but almost negligible when the system dynamics are essentially single degree of freedom.

Design Impact of Piezoelectric Actuator Nonlinearities

Data are presented illustrating the need for inclusion of piezoelectric actuator nonlinearities if accurate system modelsaredesired.Thedescribing function approach wasused inthisinvestigation asanexample.Whereastheuse of the describing functions does improve overall accuracy of the system model, it is demonstrated that the extreme sensitivity ofthedescribing functionstoamplitudeatlowactuatordisplacementsstillcompromiseson theaccuracy of system models that include voltage-controlled piezoelectric actuators. It is also demonstrated that using chargefeedback control with piezoelectricactuators makes the use of the nonlinearmodel elements lesspressing since the charge control describing functions are much nearer unity than their voltage-control counterparts. Nomenclature A = actuator cross-sectional area, m 2 C = capacitance, F c D = stiffness at constant electric displacement, Pa c E = stiffness at constant electric e eld, Pa D = electric displacement, C/m 2 d = piezoelectric constant, m/V E = electric e eld, V/m F = force,N g = piezoelectric constant, m 2 /C Kamp = voltage-feedback amplie er gain, V/V Kas = combined actuator, e exure, and amplie er gain, m/V KD = controller derivative gain, V/V KOL = open-loop system gain, m/V Kp = controller proportional gain, V/V Ksg = strain-gauge position feedback subsystem, V/m k = spring constant, N/m L = moment arm effective length, m m = driven mass, kg N = fundamental frequency representation of system nonlinearities n = number of layers in stack actuator Q = charge,C R = resistance, A S = strain T = stress, Pa t = piezoelectric material thickness, m Va = power amplie er input voltage, V x = displacement, m

Charge transfer reactions and feedback control of lignin peroxidase by phenolic compounds: Significance in lignin degradation

Lignin peroxidase (LiP), manganese-dependent peroxidase (MnP) and laccase are extracellular enzymes of white-rot fungi able to oxidise phenolic compounds to phenoxy radicals that can polymerise. LiP, however, is inhibited in the course of oxidation of phenolics, which may constitute a form of feedback control to regulate the rate of lignin oxidation and minimise the extent of lignin repolymerisation in vivo. By contrast, LiP is not inhibited to the same extent during the oxidation of veratryl alcohol. Data are presented which show that veratryl alcohol is oxidised to radical cations able to participate in intermolecular charge transfer reactions. This property of radical cations to charge transfer has led to the proposal that radical cations of veratryl alcohol, the products of LiP catalysis, may mediate in the oxidation of lignin. In addition, radical cations may assist in the reaction of LiP Compound II with reductant and thereby maintain the active peroxidase cycle. A model for net lignin breakdown is presented.