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Alireza Karimi

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Publications associées (165)

Formation of (113) texture in fcc nitride thin films and its influence on the film properties

Ayat Karimi, Alireza Karimi, Akshath Raghu Shetty

This work presents a study of XRD measurements on the development of the (113) preferential orientation with film thickness for Ti0.67Al0.33N films grown on Si(100) substrates by pulsed DC magnetron sputtering. The buildup of (113) texture was observed usi ...

Elsevier Science Sa2013

Fixed-order Controller Design for State Space Polytopic Systems by Convex Optimization

Alireza Karimi

In this paper, a new method for fixed-order controller design of systems with polytopic uncertainty in their state space representation is proposed. The approach uses the strictly positive realness (SPRness) of some transfer functions, as a tool to decoupl ...

2013

Optimal input design for direct data-driven tuning of model-reference controllers

Alireza Karimi

In recent years, direct data-driven controller tuning methods have been proposed as an alternative to the standard model-based approach for model-reference control design. In this work, the problem of input design for noniterative direct data-driven techni ...

Pergamon-Elsevier Science Ltd2013

On L2-Regularization for Virtual Reference Feedback Tuning

Alireza Karimi

The Virtual Reference Feedback Tuning (VRFT) approach is a design method that allow optimal feedback control laws to be derived from input-output (I/O) data only, without need of a model of the process. A drawback of this methods is that, in its standard f ...

2013

Frequency-Domain Robust Control Toolbox

Alireza Karimi

A new frequency-domain robust control toolbox is introduced and compared with some features of the robust control toolbox of Matlab. A summary of the theoretical background for H-infinity controller design using the spectral models is given. The main advan ...

IEEE2013

H infinity Gain-scheduled Controller Design for Rejection of Time-varying Narrow-band Disturbances Applied to a Benchmark Problem

Alireza Karimi, Zlatko Emedi

A new method for H-infinity gain-scheduled controller design by convex optimization is proposed that uses only frequency-domain data. The method is based on loop shaping in the Nyquist diagram with constraints on the weighted infinity-norm of closed-loop t ...

Lavoisier2013

Fixed-order LPV Controller Design for LPV Systems by Convex Optimization

Alireza Karimi, Zlatko Emedi

In this paper a new method for fixed-order output-feedback Linear Parameter Varying (LPV) controller design is presented. First, a set of stabilizing LPV controllers is given as an inner convex approximation of the non-convex set of all stabilizing LPV con ...

2013

Multivariable Control of Single-Inductor Dual-Output Buck Converters

Alfred Rufer, Alireza Karimi, Behrooz Bahrani

Cross regulation is the main technical drawback of a Single-Inductor Multiple-Output (SIMO) dc-dc converter. This paper proposes a multivariable digital controller to suppress the cross regulation of a Single-Inductor Dual-Output (SIDO) buck converter in C ...

Ieee2013

A data-driven approach to mixed-sensitivity control with application to an active suspension system

Alireza Karimi

In this paper, a data-driven approach is proposed to tune fixed-order controllers for unknown stable LTI plants in a mixed-sensitivity loop-shaping framework. The method requires a single set of input-output samples and it is based on convex optimization t ...

Ieee-Inst Electrical Electronics Engineers Inc2013

Robust Smith Predictor Design for Time-Delay Systems with H infinity Performance

Alireza Karimi, Vinicius De Oliveira

A new method for robust fixed-order H-infinity controller design for uncertain time-delay systems is presented. It is shown that the H-infinity robust performance condition can be represented by a set of convex constraints with respect to the parameters of ...

2013

A Multivariable Design Methodology for Voltage Control of a Single-DG-Unit Microgrid

Alfred Rufer, Alireza Karimi, Behrooz Bahrani

This paper proposes a multivariable digital control design methodology for the voltage regulation of an islanded single distributed generation (DG) unit microgrid and its dedicated load. The controller design methodology is based on a family of spectral Mu ...

2013

An LMI Formulation of Fixed-order H-infinity and H-2 Controller Design for Discrete-time Systems with Polytopic Uncertainty

Alireza Karimi

2013

Decoupled dq-Current Control of Grid-Tied Voltage Source Converters Using Nonparametric Models

Alfred Rufer, Alireza Karimi, Behrooz Bahrani

This paper presents a vector control strategy for regulating the current of grid-tied voltage source converters (VSCs) in a rotating reference frame. The proposed approach is based on shaping the open-loop and closed-loop transfer matrices of the system. S ...

Institute of Electrical and Electronics Engineers2013

H-Infinity Gain-Scheduled Controller Design for Rejection of Time-Varying Disturbances with Application to an Active Suspension System

Alireza Karimi, Zlatko Emedi

2013

Fixed-order H-infinity and H-2 Controller Design for Continuous-time Polytopic Systems: An LMI-based Approach

Alireza Karimi

In this paper, a convex set of fixed-order H-infinity and H2 dynamic output-feedback controllers for continuous-time systems with polytopic uncertainty is proposed. This approach is based on the use of some instrumental stable matrices, which operate as a ...

2013

Direct data-driven design of sparse controllers

Alireza Karimi

This paper deals with direct data-driven design of model-reference controllers whose number of parameters is constrained. Input-output (I/O) sparse controllers are introduced and proposed as an alternative to low-order controller tuning. The optimal I/O sp ...

IEEE2013

Texture mechanisms and microstructure of biaxial thin films grown by oblique angle deposition

Ayat Karimi, Alireza Karimi, Akshath Raghu Shetty

In order to understand the texture formation mechanism in thin films grown under oblique angle deposition (OAD), TiAlN films were deposited at room temperature (RT) under various incident angles. We show that both in-plane and out-of-plane crystallographic ...

Wiley-V C H Verlag Gmbh2012

Robust and Gain-Scheduled PID Controller Design for Condensing Boilers by Linear Programming

Alireza Karimi, Vinicius De Oliveira

This paper addresses the water temperature control in condensing domestic boilers. The main challenge of this process under the controller design perspective is the fact that the dynamics of condensing boilers are strongly affected by the demanded water fl ...

2012

A toolbox for robust PID controller tuning using convex optimization

Alireza Karimi, Vinicius De Oliveira, Mehdi Sadeghpour

A robust PID controller design toolbox for Matlab is presented in this paper. The design is based on linearizing or convexifying the conventional non-convex constraints on the classical robustness margins or H∞ constraints. Then the existing optimization s ...

2012

On input design for direct data-driven controller tuning

Alireza Karimi

In recent years, noniterative Correlation-based Tuning (CbT) and Virtual Reference Feedback Tuning (VRFT) have been proposed as an alternative to the standard model-based approach for model-reference control design. In this work, the problem of input desig ...

2012

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