PowerPoint-presentation

Hur fr man system att uppfra sig som man vill? Reglerteknik och intressanta tillmpningarCarl-Fredrik Lindberg, 2013-04-25Single and Double Inverted PendulumMovie found on internet http://vimeo.com/29522362

Automatic Control (Reglerteknik in Swedish)3Automatic control gives:StabilityFast disturbance rejectionSmall variations in controlled variablesEtc.Modeling the tank dynamicsTuning the PID controller

Automatic control gives:Control of the processSmaller variations in controlled variables gives:Better quality and less products that needs to be wastedStability, reliability and less unplanned production stopsHigher production rate, due to smaller variations makes it possible to increase speed.Improved production efficiency and energy efficiency by accurate control at optimum operating points

3How a control engineer sees the world4Set-pointsMeasurement noiseMeasureable disturbancesNon measureable disturbances Controller ProcessFeedbackFeed-forwardControl signalsMeasured outputsIt is desired to control the process outputs to track desired set-pointsDisturbances disturb the process, if they are measureable feedforward can be applied, which better rejects themFeedback is necessary due to modeling errors and un-measurable disturbancesMeasurement noise influence the control signal, which may have to be considered in controller design

4Automatic Control5ModelingPhysical models, grey-box, black-box, Controller designFeedback, feedforward, stability, performance, robustness, adaptive, EstimationStates, model parameters, DiagnosticsFault detection and isolation, OptimizationProject examples6EM Stabilizer in Galvanizing Lines7

Stabilization of strip gives reduced zinc over-coating

IdeaControl position of metal strip by electro magnetsQualityReduced variation of coating thicknessCloser distance nozzle to strip enables thinner coatingCorrection of various strip shapesProductivityIncreased line speedCost SavingsReduced over coating Zinc savingsEnvironmentReduced noise from air knife

7EM Stabilizer in Galvanizing Lines8

Improved strip position damping with EM Stabilizer

EM Control9

Simulation of the flowValidation of model with PIV measurements in water modelContinuous casting process

Water modelControl of the steel flow in the mold gives higher steel qualityModeling, simulation and control of a continuous casting process with electro-magnetic brakeGoal: Increased steel quality & production rateWater model built for model verification and experimentsThe electromagnetic brake increases steel quality by stabilizing the flow topology in the mold and controlling the flow.A stable flow with suitable velocity reduces inclusions and blisters.The electromagnetic braking power controlsmeniscus (surface) velocity.

9Paper Machine Steam Energy Fingerprint10

By quantifying steam flows and identifying energy waste, suggestions on how to improve energy efficiency are given

Project GoalQuantification of steam energy flowsBenchmarking of energy users in paper machineSuggestions to mill how to improve efficiencyBenefitSave steam energyPositive side effect Possible to increase machine speed & quality

Potential savings Results from a fingerprint2.5% Steam saving by increased reel velocity2.5% Steam saving by optimization of steam box pressure (1.5 MSEK/year)2 8% Condenser savings by repairing and/or improving operation of thermo-compressors, differential pressures, and pressure control in general.2.5 % Steam saving byincreasing hood dew point,increased wire tension,reduced superheating / installing de-superheaterseal leaks from hood and ventilation system,etc.With limited investments steam savings around 10% (6 MSEK/year) are possible to obtain, where some actions only are set-point changes.10Arc Furnace Control11

By control, optimization and EMS, the yield, energy efficiency and productivity is increasedSVC Voltage Control with FeedforwardImproved disturbance rejection after TSC switching

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A feedforward control strategy is derived to improve voltage control in a Static VAR Compensator (SVC).Purpose of feedforward is to reduce disturbances caused by the Thyristor Switched Capacitors (TSC).

12Wireless ControlNew possibilities with wireless controlIncreased flexibility to install sensorsCost for wiring disappearsLarge challengesReliabilityLatencySafetyCo-existence with other wireless systems90% of the communication could often be saved by smarter samplingDifferent sampling strategies have been developedSample as seldom as possible without losing control performanceTaking into account that information packages may be delayed or lost13

Diagnostics Control loop diagnosticsOn-line methods which automatically alarms for poor control loop performance.ExamplesDetection of oscillations and changed signal variance.Control performance measurements, Harris index etc.Classification of some faults, e.g. valve stiction, external disturbances.14

Process section diagnosticsFaults are both detected and isolatedFault examples:Detection of bias in a sensorDetection of clogging of a valveDetection of erosion in a pumpTrack heat transfer rate in heat exchangerBenefits:Early detection gives higher availabilityReduced maintenance costs.Avoids wrong dosing when sensor has drifted.

Example of fault isolation. The red bar indicates the most probable faulty signal.

Waste Water TreatmentSome examples from my Ph.D.15

Control of dissolved oxygen concentrationEstimation of dissolved oxygen dynamics

Adaptive control of external carbon flow rateThank you!

Questions?16