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Time-averaged active controller for turbofan engine fan noise reduction

JOURNAL OF AIRCRAFT 1996年第3期33卷 524-531页

作者： Thomas, RH Burdisso, RA Lane, SA Virginia Polytechnic Institute and State University Blacksburg Virginia 24061-0238

An active control system has been developed and used experimentally on an operational turbofan engine to reduce inlet tonal noise at the Pan blade passage frequency. Both single channel and multichannel systems were tested. The control approach used is the feedforward derivative measurement time-averaged adaptive algorithm. This algorithm is capable of adapting to a nonstationary system, requiring no prior knowledge of the system, A reference sensor mounted in the casing: of the fan provides the fan blade passing frequency reference signal to the controller. Microphones with a large sensing area are placed in the acoustic far field of the engine. The control algorithms minimize a cost function, the sum of the error signal mean-square-values, by activating loudspeakers that are mounted around the inlet of the engine. The control signals are obtained by filtering the reference signal with finite impulse response digital filters, The control algorithm finds the optimum Biter weights by using statistical estimates of the cost function to be minimized. A single channel control system was tested on an axisymmetric dominant mode case and produced reductions of up to 17 dB at the error microphone. The controller maintained reductions in the fan tone even as the engine speed was increased. In a traverse of the radiated sound held of the engine the fan blade passage tone was reduced over a sector of 30 deg around the error sensor with a considerable spillover increase in the fan tone outside of this sector, Two six channel control systems were developed and tested on both axisymmetric and spinning mode dominant cases, Reductions of up to 19.7 dB were achieved over large sectors around the error microphones with significantly reduced spillover.

关键词： Turbofan Engines Blade Passing Frequency Active control Eddy Current Sensors Digital Filters control algorithm Adaptive algorithm Newton's Method Sound Pressure Level Angle of Attack

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Power electronics active shunt filter with controlled dynamics

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COMPEL-THE INTERNATIONAL JOURNAL FOR COMPUTATION AND MATHEMATICS IN ELECTRICAL AND ELECTRONIC ENGINEERING 2013年第4期32卷 1337-1344页

作者： Gwozdz, Michal Poznan Univ Tech Fac Elect Engn Inst Elect Engn & Elect Poznan Poland

Purpose - The aim of the research was to find a structure of the power electronics controlled current source with extended pass band, which would better match a source output current within an input (reference) signal. Also, pulse modulation components in output current of current source should be minimized. Design/methodology/approach - The power electronics controlled current source utilizes both, the concept of the inductor with variable (controlled) inductance located at the output of an inverter and the concept of the multi-channel (interleaved) inverter. The small signal (linear) and simulation models of an active filter have been investigated. Findings - The work presents the concept of 1-phase active shunt filter with utilization of the power electronics current source about extended pass-band. Research limitations/implications - The research should be continued to achieve stability of the electrical system with variable parameters of the power network and receiver. Practical implications - The research will be continued towards realization of a laboratory model of a 3-phase active shunt filter with the DSP based control module. Social implications - Social implications are difficult to determine. Originality/value - The paper presents a new concept of the precision power electronics controlled current source with the extended pass-band. The controlled current source is the fundamental block of a power electronics active shunt filter.

关键词： control algorithm Current source Inverter Power electronics active filter Pulse modulation Simulation model Modulation methods Electronic engineering

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Optimal reorientation of a multibody spacecraft through joint motion using averaging theory

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JOURNAL OF GUIDANCE control AND DYNAMICS 2001年第4期24卷 788-795页

作者： Cerven, WT Coverstone, VL Univ Illinois Dept Aeronaut & Astronaut Engn Urbana IL 61801 USA

The problem of reorienting a multibody spacecraft using appendage joint motion is addressed. Averaging theory shows that small periodic actuation of such appendages results in a secular change in the orientation of the multibody spacecraft. The secular variation is controllable through choice of control profiles. Using optimal control theory an analytic control algorithm that minimizes the required control effort is del eloped for a four-link multibody system having zero angular momentum.

关键词： Spacecraft Models Optimal control Newton's Second Law control algorithm Euler Angles Propellant Mathematical Models International Space Station Body Reference Frame Hamiltonian Functions

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Inertia-Free Spacecraft Attitude Tracking with Disturbance Rejection and Almost Global Stabilization

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JOURNAL OF GUIDANCE control AND DYNAMICS 2009年第4期32卷 1167-1178页

作者： Sanyal, Amit Fosbury, Adam Chaturvedi, Nalin Bernstein, Dennis S. Univ Hawaii Manoa Dept Mech Engn Honolulu HI 96822 USA USAF Res Lab Space Vehicles Directorate Kirtland AFB NM 87117 USA Robert Bosch LLC Res & Technol Ctr Energy Modeling Control & Computat Grp Palo Alto CA 94304 USA Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA

We derive a continuous nonlinear control law for spacecraft attitude tracking of arbitrary continuously differentiable attitude trajectories based on rotation matrices. This formulation provides almost global stabilizability, that is, Lyapunov stability of the desired equilibrium of the error system as well as convergence from all initial states except for a subset for which the complement is open and dense. This controller thus overcomes the unwinding phenomenon associated with continuous controllers based on attitude representations, such as quaternions, that are not bijective and without resorting to discontinuous switching. The controller requires no inertia information, no information on constant-disturbance torques, and only frequency information for sinusoidal disturbance torques. For slew maneuvers (that is, maneuvers with a setpoint command in the absence of disturbances), the controller specializes to a continuous, nonlinear, proportional-derivative-type, almost globally stabilizing controller, in which case the torque inputs can be arbitrarily bounded a priori. For arbitrary maneuvers, we present an approximate saturation technique for bounding the control torques.

关键词： Spacecraft Attitude Proportional Integral Derivative Quaternions Nonlinear control Spacecraft control Attitude Dynamics Spacecraft Tracking Numerical Integration Numerical Simulation control algorithm

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New multilevel rectifier based on series connection of H-bridge cell

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IEE PROCEEDINGS-ELECTRIC POWER APPLICATIONS 2000年第4期147卷 304-312页

作者： Lin, BR Lu, HH Natl Yunlin Univ Sci & Technol Dept Elect Engn Power Elect Res Lab Touliu 640 Yunlin Taiwan

A three-level pulse-width modulation (PWM) rectifier is proposed. The control scheme is based on general logic gates to generate a three-level voltage waveform. In comparison with the two-level PWM scheme, the three-level PWM scheme can reduce the electromagnetic interference, decrease voltage stress of power semiconductors, and increase the switching frequency. a capacitor voltage compensator is used to balance two DC bus voltages. Based on the proposed control algorithm, the current harmonics of the line meet the International Electrotechnical Commission 1000-3-2 limits. The power factor of the proposed rectifier is nearly unity. The control strategy of the proposed three-level rectifier illustrates its validity and effectiveness experimentally.

关键词： current harmonics bridge circuits power semiconductors electromagnetic interference IEC 1000-3-2 limits power conversion harmonics three-level voltage waveform control scheme Power convertors and power supplies to apparatus AC-DC power convertors switching circuits H-bridge cell series connection PWM power convertors power semiconductor switches switching frequency harmonic distortion control strategy three-level PWM rectifier capacitor voltage compensator multilevel rectifier general logic gates Power semiconductor devices rectifying circuits voltage stress control algorithm

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Optimal Satellite Transfers Using Relative Motion Dynamics

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JOURNAL OF GUIDANCE control AND DYNAMICS 2009年第5期32卷 1508-1518页

作者： Ketema, Yohannes Univ Minnesota Dept Aerosp Engn & Mech Minneapolis MN 55455 USA

A first-order approximation of optimal two-burn transfers between satellite orbits within a formation is presented and discussed. The orbital transfer problem is based on the well-known fact that, to first order, such orbits are elliptic, with centers at the target or offset in the in-track direction. The methodology allows for a target in a (generally) elliptic orbit in its motion about the center of force. The solution obtained makes use of a transformation of the problem to the reference frame of an auxiliary target in circular orbit in the inertial frame. The total required vertical bar Delta v vertical bar is expressed in terms of the identifying parameters for the initial and final orbits in the formation, corresponding to their respective sizes as measured by their minor axes, location of their centers, and their orientation. This expression allows for numerical parametric studies in the case where the initial and final orbits are in the same or parallel planes. It is shown that the optimal total vertical bar Delta v vertical bar depends on the relative sizes of the orbits and the distance between their centers. When the initial and final orbits are concentric, four optimal two-burn transfers, all of the same total vertical bar Delta v vertical bar, are identified. It is further shown that the optimal vertical bar Delta v vertical bar changes with the distance between the centers of the orbits and attains a minimum when this distance is about 2.2 times the difference between the minor axes of the orbits.

关键词： Satellite Formation Flying Hohmann Transfer Clohessy Wiltshire Equation Right Ascension Aperture Synthesis Formation Flying Spacecraft Formation Perturbation Method control algorithm Solar Radiation

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Convolutive PD controller for hybrid improvement of dynamic structural systems

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SOIL DYNAMICS AND EARTHQUAKE ENGINEERING 2020年 137卷 106255-106255页

作者： Corbi, Ileana Corbi, Ottavia Li, Haitao Nanjing Forestry Univ Coll Civil Engn Nanjing 210037 Peoples R China Univ Naples Federico II Dept Struct Engn & Architecture I-80125 Naples Italy

Passively controlled structural systems may be exhibiting scarce capability in resisting dynamic solicitations under adverse special or unexpected conditions. Improvements of the overall performance of the passive system may be obtained when introducing supplemental corrective control actions, possibly coupling different technologic solutions and moving to mixed systems. In the paper the performance of a base isolation system is increased by embedding in the control layout an additional passive/active device, commanded by a newly designed control algorithm. The main novelty lays in the overall control system, which is regarded and completely newly designed as a whole rather than coupling already existing separated control systems, which are usually adopted and forced to comply with each other, thus realizing full complementarity. The proposed approach is aimed at further improving the reliability of the control system, ensuring its functionality even when unexpected adverse conditions occur, causing ineffectiveness of the main system.

关键词： Civil structures Dynamic control control algorithm Response mitigation

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Electric vehicles charging using photovoltaic: Status and technological review

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RENEWABLE & SUSTAINABLE ENERGY REVIEWS 2016年 54卷 34-47页

作者： Bhatti, Abdul Rauf Salam, Zainal Aziz, Mohd Junaidi Bin Abdul Yee, Kong Pui Ashique, Ratil H. Univ Teknol Malaysia Ctr Elect Energy Syst Johor Baharu 81310 Johor Malaysia Univ Teknol Malaysia Power Elect & Drives Res Grp Johor Baharu 81310 Johor Malaysia Univ Teknol Malaysia Insitute Future Energy Johor Baharu 81310 Johor Malaysia Govt Coll Univ Faisalabad Dept Elect Engn Faisalabad Pakistan

The integration of solar photovoltaic (PV) into the electric vehicle (EV) charging system has been on the rise due to several factors, namely continuous reduction in the price of PV modules, rapid growth in EV and concerns over the effects of greenhouse gases. Despite the numerous review articles published on EV charging using the utility (grid) electrical supply, so far, none has given sufficient emphasis on the PV charger. With the growing interest in this subject, this review paper summarizes and update all the related aspects on PV-EV charging, which include the power converter topologies, charging mechanisms and control for both PV-grid and PV-standalone/hybrid systems. In addition, the future outlook and the challenges that face this technology are highlighted. It is envisaged that the information gathered in this paper will be a valuable one-stop source of information for researchers working in this topic. (c) 2015 Elsevier Ltd. All rights reserved.

关键词： Photovoltaic (PV) system Electric vehicle (EV) charging system State of charge (SOC) Maximum power point tracking (MPPT) MPPT dc-dc converter Bi-directional Inverter Bi-directional dc-dc charger control algorithm EV charging algorithm Prediction models Optimization techniques

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Stabilization of Collective Motion in a Time-Invariant Flowfield

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JOURNAL OF GUIDANCE control AND DYNAMICS 2009年第3期32卷 771-779页

作者： Paley, Derek A. Peterson, Cameron Univ Maryland Dept Aerosp Engn College Pk MD 20742 USA

Cooperative steering controls enable mobile sampling platforms to conduct synoptic, adaptive surveys of dynamic spatiotemporal processes by appropriately regulating the space-time separation of their sampling trajectories. Sensing platforms in the air and maritime domains can he pushed off course by strong and variable environmental dynamics. However, most existing cooperative-control algorithms are based on simple motion models that do not include a flowfield. Existing models that include the flowfield often include speed control to compensate for the flow. In this paper, we describe a constant-speed self-propelled particle model that explicitly incorporates a time-invariant flowfield. Each vehicle is represented by a Newtonian particle subject to a gyroscopic steering control. We describe the Lyapunov-based design of decentralized control algorithms that stabilize collective motion in a known flowfield. In the case of a spatially variable flow, we provide an algorithm to stabilize synchronized motion, in which all of the particles move in the same direction, and circular motion, in which all of the particles orbit an inertially fixed point at a constant radius. For a spatially invariant How, we provide an algorithm to stabilize balanced motion, in which the particle position centroid is inertially fixed, and symmetric circular formations, in which the particle spacing around a circle is temporally regulated. Via the latter algorithm, we provide a method of stabilizing a circular formation in which the particles are evenly spaced in time and the formation is centered on a moving target. The theoretical results are illustrated with two numerical examples based on applications in environmental monitoring and target surveillance.

关键词： control algorithm Uniform Flow Numerical Simulation Lyapunov Stability Theory Rankine Vortex Autonomous Underwater Vehicle Ocean Currents Motion Planning Vehicle Trajectories Number of Particles

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INVESTIGATION OF MOVING-BANK MULTIPLE MODEL ADAPTIVE algorithmS

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JOURNAL OF GUIDANCE control AND DYNAMICS 1987年第1期10卷 90-96页

作者： MAYBECK, PS HENTZ, KP USAF Institute of Technology Wright-Patterson AFB OH

The feasibility of a moving-bank multiple model adaptive estimator/controller is examined. A significant reduction in the number of required elemental filters is accomplished through a dynamic redeclaration of the positions that the elemental filters occupy in parameter space (as compared to a conventional full-bank multiple model adaptive algorithm). Critical to the performance of the moving-bank estimator is the decision method that governs movement of the bank of elemental filter. Five such methods are developed, and their performances are compared to each other and to a benchmark filter with artificial knowledge of the "true" parameter value. Three adaptive controller algorithms are also generated and evaluated. A simple but physically motivated example is used to gain insights into the relative performance potentials of the proposed algorithms.

关键词： Adaptive algorithm Extended Kalman Filter Closed Loop System Linear Quadratic Gaussian control algorithm Feedback control Power Spectral Density Adaptive Filter Damping Ratio Monte Carlo Analysis

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