The Experts below are selected from a list of 80643 Experts worldwide ranked by ideXlab platform
Biao Huang - One of the best experts on this subject based on the ideXlab platform.
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a control performance benchmark subject to output variance covariance upper bound and pole placement constraint
American Control Conference, 2009Co-Authors: Biao Huang, Qinglin WangAbstract:User-specified benchmark has been reported in the literature for control Loop performance assessment. A structured closed-Loop Response which is subject to simultaneous output covariance upper bound and pole placement constraint is proposed in this paper and served as an improved user-specified benchmark against which the existing controller performance can be compared. An LMI-based approach is used to formulate this problem and a cone complementarity linearization (CCL) algorithm is applied to find a global solution. An associated model approximation problem is solved in the sense of H 2 -norm in contrast to the use of H ∞ -norm of the previous work to obtain an optimal solution. The results are evaluated in a dry process rotary cement kiln example.
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monitoring control performance via structured closed Loop Response subject to output variance covariance upper bound
Journal of Process Control, 2006Co-Authors: Fangwei Xu, Biao HuangAbstract:Abstract Owing to the process time delays, the closed-Loop Response can be divided into feedback control invariant part and feedback controller dependent part. If the latter part is replaced by a user specified Response trajectory, we refer to the resultant closed-Loop Response as structured closed-Loop Response. The user specified structured closed-Loop Response has been used as an achievable control against which one can assess performance of control Loops. In the control performance monitoring literature, the user specified Response is often given as a first-order transfer function with some specified performance requirement, such as time constant. In this paper, we solve this problem from a systematic approach, i.e., in viewpoint of a variance/covariance upper bound on the outputs. With available closed-Loop routine operating output data and process time delay/interactor matrix, the desired structured closed-Loop Response can be obtained directly via estimated closed-Loop time series model. A significant feature is that the output variance/covariance upper bound constraint can be explicitly specified according to the product specifications and is always satisfied when the problem is feasible. This desired structured closed-Loop Response can thus be served as a benchmark against which the existing controller performance can be compared. We also show that two approaches, linearizing change of variables and Frank and Wolfe algorithm, are suitable for solving this problem, which result in a full order and a reduced order structured closed-Loop Response, respectively. Both approaches are illustrated by two case studies.
Ronnie Belmans - One of the best experts on this subject based on the ideXlab platform.
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model based generation of low distortion currents in grid coupled pwm inverters using an lcl output filter
IEEE Transactions on Power Electronics, 2006Co-Authors: B Bolsens, Johan Driesen, K De Brabandere, J Van Den Keybus, Ronnie BelmansAbstract:In this paper, a single phase inductance–capacitance– inductance (LCL) output stage for grid coupled inverters is designed and built. An accurate model and observer of the output filter and the distorted grid voltage are implemented. The paper deals with the construction of a 14-state model, and the feedback control Loop to obtain adequate closed Loop Response. Simulations indicate a good performance of the controller, with a total harmonic current distortion (THD) below 1%. Experimental results confirm simulations, and illustrate the correct operation of the Kalman observer to estimate the distorted grid voltage (THD 3%). The observer only uses the inverter current measurement as input. The output filter effectively reduces the pulsewidth modulation harmonics in the grid current.
S Sundaramoorthy - One of the best experts on this subject based on the ideXlab platform.
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pid controller tuning for desired closed Loop Responses for siso systems using impulse Response
Computers & Chemical Engineering, 2008Co-Authors: M Ramasamy, S SundaramoorthyAbstract:Abstract Most of the proportional-integral-derivative (PID) controller tuning methods reported in literature are based on the approximate plant models (FOPDT or SOPDT models) derived from the step Response of the plant. In this paper, a new method of designing PID controllers using ‘impulse Response’ instead of ‘step Response’ of the plant is presented. Treating the impulse Response of the plant as a statistical distribution, the ‘mean’ and the ‘variance’ of the distribution are calculated and used in the calculation of PID controller parameters. Thus, the proposed method requires no approximation of the plant by any model. In this paper, a direct synthesis approach to PID controller design is proposed that makes use of Maclaurin series of the desired closed-Loop transfer function, truncated up to the first three terms. PID controller parameters are synthesized to match the closed-Loop Response of the plant to the desired closed-Loop Response. Formulae for the calculation of PID controller tuning parameters are derived for the desired closed-Loop Response models of the types FOPDT and SOPDT. Only stable SISO systems are considered. The PID controllers tuned result in closed-Loop Responses very close to the desired Response and perform equally well compared to other tuning methods reported in literature.
Rames C Panda - One of the best experts on this subject based on the ideXlab platform.
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synthesis of pid controller for unstable and integrating processes
Chemical Engineering Science, 2009Co-Authors: Rames C PandaAbstract:Properly designed controllers provide stable closed-Loop Response for open-Loop unstable processes. Internal model controller equivalent PID tuning rules for low order unstable plus dead time systems are synthesized in this work. The controller is approximated near the vicinity of zero (origin). Controller parameters are derived by equating the closed-Loop Response to a control-signature (desired closed-Loop Response) involving a user defined tuning parameter, λ. Simulations are carried out to show the performance of the proposed tuning scheme for both set point and disturbance rejection cases.
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synthesis of pid tuning rule using the desired closed Loop Response
Industrial & Engineering Chemistry Research, 2008Co-Authors: Rames C PandaAbstract:Proportional−integral−derivative (PID) controllers are widely used in industry, because of their simple structure and ease in implementation. A tuning method based on the IMC−PID rule is synthesized for stable single-input−single-output systems. The controller transfer function is expanded, in the vicinity of zero in the complex plane, using a Laurent series, to derive analytical expressions for controller parameters. A tuning parameter is chosen to determine the stability of the Response/closed-Loop system. PID parameters are obtained for different types of processes, and related robustness issues are also discussed.
Fangwei Xu - One of the best experts on this subject based on the ideXlab platform.
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monitoring control performance via structured closed Loop Response subject to output variance covariance upper bound
Journal of Process Control, 2006Co-Authors: Fangwei Xu, Biao HuangAbstract:Abstract Owing to the process time delays, the closed-Loop Response can be divided into feedback control invariant part and feedback controller dependent part. If the latter part is replaced by a user specified Response trajectory, we refer to the resultant closed-Loop Response as structured closed-Loop Response. The user specified structured closed-Loop Response has been used as an achievable control against which one can assess performance of control Loops. In the control performance monitoring literature, the user specified Response is often given as a first-order transfer function with some specified performance requirement, such as time constant. In this paper, we solve this problem from a systematic approach, i.e., in viewpoint of a variance/covariance upper bound on the outputs. With available closed-Loop routine operating output data and process time delay/interactor matrix, the desired structured closed-Loop Response can be obtained directly via estimated closed-Loop time series model. A significant feature is that the output variance/covariance upper bound constraint can be explicitly specified according to the product specifications and is always satisfied when the problem is feasible. This desired structured closed-Loop Response can thus be served as a benchmark against which the existing controller performance can be compared. We also show that two approaches, linearizing change of variables and Frank and Wolfe algorithm, are suitable for solving this problem, which result in a full order and a reduced order structured closed-Loop Response, respectively. Both approaches are illustrated by two case studies.
