Publications by Alireza Karimi

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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 ...

A new robust controller design method that satisfies the H-infinity criterion is developed for linear time-invariant single-input single-output (SISO) systems. A data-driven approach is implemented in order to avoid the unmodeled dynamics associated with p ...

This paper treats the problem of primary and secondary control design in low-inertia power grids with mixed lines and a large amount of inverter-interfaced generation. A dynamic phasor model is developed that represents the electromagnetic and electromecha ...

A method to design decentralized PID controllers for MIMO systems is presented in this paper. Each loop is designed separately, but the Gershgorin bands are considered to take interactions into account. The method uses different design parameters: The infi ...

This paper presents a data-driven controller-tuning algorithm that includes a sufficient condition for closed-loop stability. This stability condition is defined by a set of convex constraints on the Fourier transform of specific auto- and cross-correlatio ...

The connection of a DG unit to a weak power system is challenging due to stability issues resulted from dynamic interactions between the DG unit and the grid. LCL-based DG unit is a particularly challenging case due to the presence of a high resonant peak ...

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 ...

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 ...

Convex parameterization of fixed-order robust stabilizing controllers for systems with polytopic uncertainty is represented as an LMI using KYP Lemma. This parameterization is a convex inner-approximation of the whole non-convex set of stabilizing controll ...

In this paper, a data-driven method for controller design with constraints on the positive-realness of closed-loop transfer functions over an arbitrary set of frequencies is proposed. The positive-realness of a closed-loop transfer function is represented ...

In this paper, a new algorithm is proposed for the design of a family of controllers to be used within an adaptive switching control scheme. The resulting switching controller is able to attenuate the effects of disturbances having uncertain and possibly t ...

A controller design method using a frequency criterion is proposed in this paper. The frequency criterion is defined as the weighted sum of squared errors between the specified and computed values of the design parameters. These are the infinity-norm of th ...

This paper presents a comprehensive data-driven distributed combined primary/secondary controller design method for microgrids. This method provides transient and steady-state performance including power-sharing and voltage and frequency restoration while ...

An overview of the recent works on proportional integral derivative (PID) controller tuning methods based on specifications on the infinity-norm of the sensitivity functions is presented. The presented approach is very flexible relative to the controller s ...

This paper presents a PID controller design method for stable minimum- phase systems. The approach is similar to the one proposed in the so-called modified Ziegler- Nichols method, where only one point on the frequency response of the plant is measured and ...

We consider the problem of distributed primary and secondary frequency control in inverter-based microgrids with meshed topology. A dynamic phasor modeling approach is presented that accurately represents the dynamics of the grid while being suitably simpl ...

A new model-reference data-driven approach is presented which uses the frequency response data of a system in order to avoid the problem of unmodeled dynamics associated with low-order parametric models. It is shown that a convex optimization problem can b ...

This paper addresses the control of the blending process in cement industries. This process can be modeled by a nonlinear multivariable system with large parametric uncertainty. Using a specific transformation, a linear parameter varying (LPV) model with s ...

A new data-driven approach using the frequency response function (FRF) of a system is proposed for designing robust-fixed structure digital controllers for particle accelerators' power converters. This design method ensures that the dynamics of a system ar ...

This paper proposes a data-driven test for closed-loop stability. The test is based on a non-conservative stability condition that can be veriﬁed without having to actually implement the controller. It uses a set of measurements from the plant but does not ...

Alireza Karimi

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

Robust H-infinity Controller Design Using Frequency-Domain Data via Convex Optimization

Decentralized and Distributed Transient Control for Microgrids

PID Controller Design for Multivariable Systems Using Gershgorin Bands

Data-driven controller tuning with integrated stability constraint

A Robust Active Damping Control Strategy for an LCL-based Grid-connected DG Unit

On L2-Regularization for Virtual Reference Feedback Tuning

Frequency-Domain Robust Control Toolbox

Robust Pole Placement of Systems with Polytopic Uncertainty Via Convex Optimization

Data-Driven Passivity-Based Current Controller Design for Power-Electronic Converters of Traction Systems

Design of a Switching Controller for Adaptive Disturbance Attenuation with Guaranteed Stability

PID Controller Design with Specifications on the Infinity-Norm of Sensitivity Functions

Data-Driven Distributed Combined Primary and Secondary Control in Microgrids

Robust PID controller tuning with specifications on the infinity-norm of sensitivity functions

PID controller design with constraints on sensitivity functions using loop slope adjustment

Robust Distributed Averaging Frequency Control of Inverter-Based Microgrids

A data-driven approach to model-reference control with applications to particle accelerator power converters

Robust gain-scheduled blending control of raw-mix quality in cement industries

A Robust Data-Driven Controller Design Methodology With Applications to Particle Accelerator Power Converters

Data-driven controller validation