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Operating Point (operating + point)
Selected AbstractsGain-scheduling control of a rotary inverted pendulum by weight optimization and H, loop shaping procedureELECTRICAL ENGINEERING IN JAPAN, Issue 2 2008Kazuhiro Yubai Abstract Gain-scheduling control is an effective method for use with plants whose dynamics change significantly according to the operating point. The frozen parameter method, a practical gain-scheduling controller synthesis method, interpolates the controllers designed at prespecified (frozen) operating points according to the current operation point. Hyde and Glover proposed a gain-scheduling control method in which the H, loop shaping procedure is adopted as a controller synthesis method at each operating point. The H, loop shaping procedure is based on loop shaping of an open loop characteristic by frequency weights and is known to be effective for plants with bad condition numbers. However, weight selection satisfying the control specifications is a difficult job for a designer. This paper describes the design of suboptimal weights and a controller by means of an algorithm that maximizes the robust stability margin and shapes the open-loop characteristic into the desired shape at each operating point. In addition, we formulate the weight optimization problem as a generalized eigenvalue minimization problem, which reduces the burden on the designer in weight selection. Finally, we realize a robust, high-performance control system by scheduling both weights and controllers. The effectiveness of the proposed control system is verified in terms of the achieved robust stability margin and the experimental time responses of a rotary inverted pendulum, which involves strong nonlinear dynamics. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 30,40, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20647 [source] Computation of time delay margin for power system small-signal stabilityEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 7 2009Saffet AyasunArticle first published online: 19 JUN 200 Abstract With the extensive use of phasor measurement units (PMU) in the wide-area measurement/monitoring systems (WAMS), time delays have become unavoidable in power systems. This paper presents a direct and exact method to compute the delay margin of power systems with single and commensurate time delays. The delay margin is the maximum amount of time delay that the system can tolerate before it becomes unstable for a given operating point. First, without using any approximation or substitution, the transcendental characteristic equation is converted into a polynomial without the transcendentality such that its real roots coincide with the imaginary roots of the characteristic equation exactly. The resulting polynomial also enables us to easily determine the delay dependency of the system stability and the sensitivities of crossing roots with respect to time delay. Then, an expression in terms of system parameters and imaginary root of the characteristic equation is derived for computing the delay margin. The proposed method is applied to a single-machine-infinite bus (SMIB) power system with an exciter. Delay margins are computed for a wide range of system parameters including generator mechanical power, damping and transient reactance, exciter gain, and transmission line reactance. The results indicate that the delay margin decreases as the mechanical power, exciter gain and line reactance increase while it increases with increasing generator transient reactance Additionally, the relationship between the delay margin and generator damping is found be relatively complex. Finally, the theoretical delay margin results are validated using the time-domain simulations of Matlab. Copyright © 2008 John Wiley & Sons, Ltd. [source] Online trained support vector machines-based generalized predictive control of non-linear systemsINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 10 2006S. Iplikci Abstract In this work, an online support vector machines (SVM) training method (Neural Comput. 2003; 15: 2683,2703), referred to as the accurate online support vector regression (AOSVR) algorithm, is embedded in the previously proposed support vector machines-based generalized predictive control (SVM-Based GPC) architecture (Support vector machines based generalized predictive control, under review), thereby obtaining a powerful scheme for controlling non-linear systems adaptively. Starting with an initially empty SVM model of the unknown plant, the proposed online SVM-based GPC method performs the modelling and control tasks simultaneously. At each iteration, if the SVM model is not accurate enough to represent the plant dynamics at the current operating point, it is updated with the training data formed by persistently exciting random input signal applied to the plant, otherwise, if the model is accepted as accurate, a generalized predictive control signal based on the obtained SVM model is applied to the plant. After a short transient time, the model can satisfactorily reflect the behaviour of the plant in the whole phase space or operation region. The incremental algorithm of AOSVR enables the SVM model to learn the new training data pair, while the decremental algorithm allows the SVM model to forget the oldest training point. Thus, the SVM model can adapt the changes in the plant and also in the operating conditions. The simulation results on non-linear systems have revealed that the proposed method provides an excellent control quality. Furthermore, it maintains its performance when a measurement noise is added to the output of the underlying system. Copyright © 2006 John Wiley & Sons, Ltd. [source] Influence of high rates of supplemental cooled EGR on NOx and PM emissions of an automotive HSDI diesel engine using an LP EGR loopINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 15 2008A. Maiboom Abstract Previous experimental studies on diesel engine have demonstrated the potential of exhaust gas recirculation (EGR) as an in-cylinder NOx control method. Although an increase in EGR at constant boost pressure (substitution EGR) is accompanied with an increase in particulate matter (PM) emissions in the conventional diesel high-temperature combustion (HTC), the recirculation of exhaust gases supplementary to air inlet gas (supplemental EGR) by increasing the boost pressure has been suggested as a way to reduce NOx emissions while limiting the negative impact of EGR on PM emissions. In the present work, a low-pressure (LP) EGR loop is implemented on a standard 2.0 l automotive high-speed direct injection (HSDI) turbocharged diesel engine to study the influence of high rates of supplemental cooled EGR on NOx and PM emissions. Contrary to initial high-pressure (HP) EGR loop, the gas flow through the turbine is unchanged while varying the EGR rate. Thus, by closing the variable geometry turbine (VGT) vanes, higher boost pressure can be reached, allowing the use of high rates of supplemental EGR. Furthermore, recirculated exhaust gases are cooled under 50°C and water vapour is condensed and taken off from the recirculated gases. An increase in the boost pressure at a given inlet temperature and dilution ratio (DR) results in most cases an increase in NOx emissions and a decrease in PM emissions. The result of NOx,PM trade-off, while varying the EGR rate at fixed inlet temperature and boost pressure depends on the operating point: it deteriorates at low load conditions, but improves at higher loads. Further improvement can be obtained by increasing the injection pressure. A decrease by approximately 50% of NOx emissions while maintaining PM emission level, and brake specific fuel consumption can be obtained with supplemental cooled EGR owing to an LP EGR loop, compared with the initial engine configuration (HP moderately cooled EGR). Copyright © 2008 John Wiley & Sons, Ltd. [source] Real-time optimization of dynamic systems using multiple unitsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 13 2007B. Srinivasan Abstract Model-free, unconstrained, real-time optimization of the operating point of a dynamic system involves forcing the gradient of the cost function to zero. In these methods, gradient estimation is a key issue, for which methods that perturb the input over time are used. The main limitation of these methods is that they require the dynamics of the adaptation to be two orders of magnitude slower than the system dynamics. To circumvent this limitation, a novel, simple, yet effective way of estimating the gradient is presented in this paper. Multiple identical units with non-identical inputs are used and the gradient is computed via finite difference. Thus, the perturbation is along the ,unit dimension', thereby allowing a faster adaptation. The convergence of the scheme is rigorously established via Lyapunov analysis. An illustrative example is provided where the proposed scheme resulted in an 100-fold improvement in the time needed for convergence. Copyright © 2007 John Wiley & Sons, Ltd. [source] Control of the Aero-Electric Power Station,an exciting QFT application for the 21st centuryINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 7 2003Per-Olof Gutman Abstract The Aero-Electric Power Station is the ultimate solar power station, utilizing the dry, hot air of Earth's desert zones. By spraying water at the top of e.g. a 1200 m tall chimney with a diameter of 400 m, the air is cooled by evaporation and flows downwards through turbines at the bottom, generating 380 MW of net electric power. The Aero-Electric Power Station is still in the planning stage, and this paper belongs to a long series of feasibility studies. The current ,truth' model of the Aero-Electric Power Station is a one-dimensional partial differential equation model. The external slowly changing weather, defined as the mean air pressures, temperatures and humidity at the top and bottom of the tower, determines the optimal operating point, i.e. the optimal water spray flow and turbine velocity that give the largest net power. The gross power produced by the turbine is partly delivered to the grid and partly to pump sea water to spray water reservoirs. The reservoirs make it possible to use the pumping power and the spray flow rate as control. Wind changes cause significant deviations from the mean external air pressures, requiring closed loop regulation to keep the rotor velocity constant. The Aero-Electric Power Station may be modelled as an uncertain, unstable irrational transfer function, with two disturbances (external air pressure deviations at top and bottom), two control variables (turbine power and spray flow), and one output (rotor velocity), without a cascaded structure, giving rise to a robust load sharing control problem. A robust linear feedback regulator is designed by QFT, in such a way that the load of regulation is shared between the two control inputs. A closed loop step response simulation for one operating condition, using the ,truth' model, demonstrates the design. Copyright © 2003 John Wiley & Sons, Ltd. [source] Ka-band link optimization with rate adaptation for Mars and lunar communicationsINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2007Jun Sun Abstract On-going development of Ka-band capability for the Deep Space Networks (DSN) will radically increase the bandwidth available to support advanced mission concepts envisioned for future robotic as well as human exploration of Mars and beyond. While Ka-band links can operate at much higher data rate than X-band, they are much more susceptible to fluctuating weather conditions and manifest a significant trade-off between throughput and availability. If the operating point is fixed, the maximum average throughput for deep space Ka-band link is achieved at about 80% availability, i.e. weather-related outages will occur about 20% of the time. Low availability increases the complexity of space mission operation, while higher availability would require additional link margins that lowers the overall throughput. To improve this fundamental throughput-availability trade-off, data rate adaptation based on real-time observation of the channel condition is necessary. In this paper, we model the Ka-band channel using a Markov process to capture the impact of the temporal correlation in weather conditions. We then develop a rate adaptation algorithm to optimize the data rate based on real time feedback on the measured channel conditions. Our algorithm achieves both higher throughput and link availability as compared to the constant rate scheme presently in use. Copyright © 2007 John Wiley & Sons, Ltd. [source] A method of measuring oil consumption by labelling with radioactive bromineLUBRICATION SCIENCE, Issue 3 2000H. Zellbeck Abstract A method of determining the oil consumption rate of combustion engines is presented. It is based on labelling the individual oil fractions of engine oil with radioactive bromine isotope82 Br and on the quantitative absorption of radioactive bromine compounds in the exhaust gas in an aqueous solution of nitric acid and silver nitrate. The advantages of this method are that the oil that is consumed in the exhaust gas can be directly measured, without the fluctuating amounts of oil in the sump influencing the result, and the behaviour of the individual components of the oil in the consumption process can be determined. The test is quick, only twenty minutes being required to detect oil consumption at one operating point; and with a single labelling, the oil consumption at a great number of working engine points can be measured 82 Br has a short half-life of only 36 h, so that compliance with radiation protection measures is inexpensive and investigations can be carried out using a conventional testing device. As part of the research project, a study was made of the influence of different base oil types, with and without polymer additives, on consumption. Results showed that Noack evaporation loss correlated with oil consumption only with boiling fractions of exactly the same base oil, and not with different, in particular synthetic, base oils; that polymer additives (VI improvers) significantly reduced the rate of oil consumption; and that the polymer additive and the type of base oil both had more influence on oil consumption than viscosity. [source] Dynamic ,back-off' analysis: use of piecewise linear approximationsOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 2 2003José L. Figueroa Abstract The operating point of a process is usually computed by optimizing an objective function, e.g. the profit, subject to some plant characteristics. Typically, the resulting point lies on the boundary of the operating region. At this point, the presence of disturbances can easily cause constraint violations and make the process move to the unfeasible region. Then, it is necessary to move the operating point away into the feasible region by considering the effect that the expected disturbances will have on the operation of the plant. The purpose of this paper is to present an efficient algorithm to modify the operating point in order to keep feasibility (both in steady-state and along transitory) in the process operation against the disturbances. Copyright © 2003 John Wiley & Sons, Ltd. [source] Design and Control of a Pneumatic Hybrid ActuatorPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2005M. Dhanu Singh To simulate arbitrary force/displacement relationships, a hybrid actuator consisting of a .uidic muscle and a linear pressure spring is presented. Fluidic Muscles are interesting in their use as actuators in robotics, since they have a high power/weight ratio, a slip-stick free motion and a long durability. The operating point is de.ned as the half contracted-stroke of the muscle. The present paper describes a procedure to simulate virtual stiffness of a linear actuator by choosing an operating point of the pre-stressed muscle and applying PID Control to produce desired forces as function of state. The results are presented for a testbed. It is shown how the aforementioned control scheme produces a rapid and .exible stiffnes simulation. The device can be employed for later use in general environments such as motion simulations. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fully Autonomous Preload-Sensitive Control of Implantable Rotary Blood PumpsARTIFICIAL ORGANS, Issue 9 2010Andreas Arndt Abstract A pulsatility-based control algorithm with a self-adapting pulsatility reference value is proposed for an implantable rotary blood pump and is to be tested in computer simulations. The only input signal is the pressure difference across the pump, which is deduced from measurements of the pump's magnetic bearing. A pulsatility index (PI) is calculated as the mean absolute deviation from the mean pressure difference. As a second characteristic, the gradient of the PI with respect to the pump speed is derived. This pulsatility gradient (GPI) is used as the controlled variable to adjust the operating point of the pump when physiological variables such as the systemic arterial pressure, left ventricular contractility, or heart rate change. Depending on the selected mode of operation, the controller is either a linear controller or an extremum-seeking controller. A supervisory mechanism monitors the state of the system and projects the system into the region of convergence when necessary. The controller of the GPI continuously adjusts the reference value for PI. An underlying robust linear controller regulates the PI to the reference value in order to take into account changes in pulmonary venous return. As a means of reacting to sudden changes in the venous return, a suction detection mechanism was included. The control system is robustly stable within a wide range of physiological variables. All the clinician needs to do is to select between the two operating modes. No other adjustments are required. The algorithm showed promising results which encourage further testing in vitro and in vivo. [source] A Passive Magnetically and Hydrodynamically Suspended Rotary Blood PumpARTIFICIAL ORGANS, Issue 3 2009Martin Stoiber Abstract A combined hydrodynamic,magnetic bearing allows the design of rotary blood pumps that are not encumbered with mechanical bearings and magnets requiring sensors or electrical power. However, such pumps have so far needed very small and accurately manufactured gaps between rotor and housing to assure effective hydromagnetic bearing behavior. In order to use this concept in disposable pump heads, a design that allows larger rotor-housing gaps, and thus larger manufacturing tolerances, is needed. A pump with passive magnetic bearings and a gap between rotor and housing in the range of 0.5 mm was designed. Numerical simulations were performed to optimize the rotor geometry at low levels of shear stress. An experimental test stand was used to find a range of speeds and gap settings that resulted in low levels of vibration and useful pressure,flow relationships. Three different rotor geometries were tested using a viscosity-adjusted test fluid. Blood damage tests were conducted within the desirable range of speeds and gap settings. In this study stable pump performance was demonstrated at total gap widths between 0.3 and 0.7 mm at flows of 0,10 L/min, with afterloads up to 230 mm Hg. Best performance was achieved with rotors sliding on a fluid pillow between the rotor and the outer housing at a gap distance of 50 to 250 µm. The inner gap distance, between the rotor and the inner housing, could be as great as 500 µm. Hemolysis tests on the prototype within the chosen operating range showed lower values (NIH = 0.0029 ± 0.0012 g/100 L) than the Biomedicus BP-80 pump (NIH = 0.0033 ± 0.0011 g/100 L). In conclusion, it is possible to build rotary blood pumps with passive hydromagnetic bearings that have large gaps between their rotors and housings. Rotor behavior is sensitive to the position of the permanent magnetic drive unit. To minimize vibration and blood damage, the fluid gaps and the rotational speed have to be adjusted according to the desired operating point of the pump. Further study is needed to optimize the magnetic drive unit and to ascertain its ability to withstand inertial loads imposed by sudden movements and external shock. [source] Robust control of the activated sludge processBIOTECHNOLOGY PROGRESS, Issue 3 2009R. David Abstract In this work, a robust control strategy is proposed for maintaining the oxygen concentration in the aerobic tank and the pollutant, i.e., ammonium, nitrate, nitrite, concentrations at acceptable levels in the effluent water at the outlet of the activated sludge process. To this end, the Activated Sludge Model no. 1 (ASM1) is first reduced using biological arguments and a singular perturbation method, and a simplified model of the secondary settler is included. In contrast with previous studies that make use of piecewise linear models, an average operating point is evaluated using available data (here data from the COST Action 624) and the reduced-order model is linearized around it using standard techniques. Finally, a H2 robust control strategy acting on the oxygen injection and the recirculated flow rate is designed and tested in simulation. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Gain-scheduling control of a rotary inverted pendulum by weight optimization and H, loop shaping procedureELECTRICAL ENGINEERING IN JAPAN, Issue 2 2008Kazuhiro Yubai Abstract Gain-scheduling control is an effective method for use with plants whose dynamics change significantly according to the operating point. The frozen parameter method, a practical gain-scheduling controller synthesis method, interpolates the controllers designed at prespecified (frozen) operating points according to the current operation point. Hyde and Glover proposed a gain-scheduling control method in which the H, loop shaping procedure is adopted as a controller synthesis method at each operating point. The H, loop shaping procedure is based on loop shaping of an open loop characteristic by frequency weights and is known to be effective for plants with bad condition numbers. However, weight selection satisfying the control specifications is a difficult job for a designer. This paper describes the design of suboptimal weights and a controller by means of an algorithm that maximizes the robust stability margin and shapes the open-loop characteristic into the desired shape at each operating point. In addition, we formulate the weight optimization problem as a generalized eigenvalue minimization problem, which reduces the burden on the designer in weight selection. Finally, we realize a robust, high-performance control system by scheduling both weights and controllers. The effectiveness of the proposed control system is verified in terms of the achieved robust stability margin and the experimental time responses of a rotary inverted pendulum, which involves strong nonlinear dynamics. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 30,40, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20647 [source] Performance analysis of nonlinearly amplified M-QAM signals in MIMO channelsEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2008Ahmed Iyanda Sulyman In this paper, we investigate the effect of nonlinearity in multiple input multiple output (MIMO) channels. New results on the error rate performance of several M-QAM constellations in linear and nonlinear MIMO channels are presented. The results show that for any MIMO configuration, performance degradation due to nonlinearity reduces as the fading gets more severe, and for a particular fading channel, the degradation increases as the MIMO dimension is increased. Optimum operating points for nonlinear amplifiers in MIMO channels are then reported. At these points, highly efficient utilisation of the amplifiers are achieved at minimal performance loss. Copyright © 2007 John Wiley & Sons, Ltd. [source] Multiple operating points in a square-root domain first-order filterINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 1 2007Carlos A. De La Cruz-Blas Abstract In this paper novel corrective circuits to avoid multiple operating points in a square-root domain first-order filter are proposed. By employing a DC test it is demonstrated that the filter possesses three operating points (two stable and one unstable) and the corrective circuits enforce the proper operating mode. The corrective circuits and filter are able to operate with very low supply voltages (as low as VGS+2VDSsat). Moreover, a detailed analysis concerning the impact that produces the corrective circuits on the filter performance is discussed. Both measurement and simulation results are provided to validate the circuits and analysis employed. Copyright © 2006 John Wiley & Sons, Ltd. [source] Power allocation in the context of dimensioning the air-interface of third generation W-CDMA-based cellular systemsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 5 2002P. Demestichas Abstract The adoption of W-CDMA as an essential component of the air-interface of third-generation cellular systems brings to the foreground the need for new planning methodologies and software tools. In this perspective, this paper addresses planning problems that are important to the dimensioning of W-CDMA-based cellular networks. The problems aim at finding the optimal feasible allocation of transmission power to the sets of uplink and downlink connections that should be supported by the system, so as to cope with a corresponding traffic load scenario. The problems are concisely defined, mathematically formulated and solved by means of two computationally efficient, novel algorithms. The solutions of the problems may be seen as operating points at which the system performance should be driven. Finally, numerical results are presented and concluding remarks are drawn. Copyright © 2002 John Wiley & Sons, Ltd. [source] Generalized sampled-data hold functions for robust multivariable tracking and disturbance rejectionOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 2 2001Herbert Werner Abstract A new design procedure for a multivariable sampled-data output feedback controller with generalized hold function is proposed. The controller can be designed for different operating points simultaneously. The design of the hold function is carried out in two steps: first the closed-loop discrete-time behaviour is determined by choosing a suitable output injection gain; integral action is incorporated to guarantee zero steady-state error. In a second step this discrete-time behaviour is approximately realized by output feedback with generalized hold. Minimization of a quadratic performance index simultaneously for all operating points yields hold functions with good intersample behaviour. A practical design example and experimental results illustrate the proposed method. Copyright © 2001 John Wiley & Sons, Ltd. [source] Influence from front contact sheet resistance on extracted diode parameters in CIGS solar cellsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 2 2008Ulf Malm Abstract The extraction of one-diode model parameters from a current,voltage (J,V) curve is problematic, since the model is one-dimensional while real devices are indeed three-dimensional. The parameters obtained by fitting the model curve to experimental data depend on how the current is collected, and more specifically the geometry of the contact. This is due to the non-uniform lateral current flow in the window layers, which leads to different parts of the device experiencing different front contact voltage drop, and hence different operating points on the ideal J,V curve. In this work, finite element simulations of three-dimensional contact structures are performed and compared to experimental data on Cu(In,Ga)Se2 -based solar cell devices. It is concluded that the lateral current flow can influence the extracted parameters from the one-diode model significantly if the resistivity of the front contact material is high, or if there is no current collecting grid structure. These types of situations may appear in damp heat-treated cells and module type cells, respectively. Copyright © 2007 John Wiley & Sons, Ltd. [source] Parametric Study of Blade Tip Clearance, Flow Rate, and Impeller Speed on Blood Damage in Rotary Blood PumpARTIFICIAL ORGANS, Issue 6 2009Nahn Ju Kim Abstract Phenomenological studies on mechanical hemolysis in rotary blood pumps have provided empirical relationships that predict hemoglobin release as an exponential function of shear rate and time. However, these relations are not universally valid in all flow circumstances, particularly in small gap clearances. The experiments in this study were conducted at multiple operating points based on flow rate, impeller speed, and tip gap clearance. Fresh bovine red blood cells were resuspended in phosphate-buffered saline at about 30% hematocrit, and circulated for 30 min in a centrifugal blood pump with a variable tip gap, designed specifically for these studies. Blood damage indices were found to increase with increased impeller speed or decreased flow rate. The hemolysis index for 50-µm tip gap was found to be less than 200-µm gap, despite increased shear rate. This is explained by a cell screening effect that prevents cells from entering the smaller gap. It is suggested that these parameters should be reflected in the hemolysis model not only for the design, but for the practical use of rotary blood pumps, and that further investigation is needed to explore other possible factors contributing to hemolysis. [source] Minimizing operating points for way point tracking of an unstable nonlinear plantASIAN JOURNAL OF CONTROL, Issue 1 2010Guangyu Liu Abstract Stability analysis of way point tracking of an open loop unstable nonlinear system is overwhelmingly ignored in the literature. Taking a spherical inverted pendulum as an example, the stability issue of way point tracking for an unstable nonlinear system is properly addressed and solved by incorporating nonlinear stabilizing controllers that could minimize the number of operating points. The underlying principle in stability analysis of way point tracking easily extends to other unstable nonlinear systems. Effectiveness of the proposed idea is evaluated in computer simulation. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Design of Simulated Moving Bed Plants for Reduced PuritiesCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2010M. Fütterer Abstract Simulated moving bed (SMB) chromatography is an established separation technology, where chromatographic columns are interconnected to a ring. The feeding and drains are switched over cyclically, such that a continuous separation becomes possible. For a faultless operation, the volumetric flow rates and switching time must be carefully adjusted. Therefore, it is desirable to calculate these values in dependence of the model parameters exactly. In this contribution, a new method is introduced to compute operating points for dispersion-free SMB plants and to predict the associated time trajectories of the concentrations at the drains in cyclic steady state for user-specified purities and degree of robustness. Simulation results are presented to show the potential of this new method. [source] | |||||||||||||||||||||||||