Showing papers by "Behrooz Bahrani published in 2014"

Multivariable Control of Single-Inductor Dual-Output Buck Converters

Abstract: Cross regulation is the main technical challenge 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 continuous conduction mode (CCM) operation. The controller design methodology originates from the open-loop shaping of the multi-input multi-output (MIMO) systems. The control design procedure includes: 1) determination of a family of nonparametric models of the SIDO converter at operating points of interest, 2) determination of the class of the controller, and 3) system open-loop shaping by the convex minimization of the summation of the square second norm of the errors between the system open-loop transfer function matrices and a desired open-loop transfer function matrix. The proposed controller minimizes the coupling between the outputs of the SIDO converter and provides satisfactory dynamic performance in CCM operation. This paper describes the theoretical aspects involved in the design procedure of the controller and evaluates the performance of the controller based on simulation studies and experiments.

High-Order Vector Control of Grid-Connected Voltage-Source Converters With LCL-Filters

Abstract: This paper proposes a vector control strategy for LCL-filter-based grid-connected voltage-source converters (VSCs). The proposed control strategy is inherently capable of attenuating the resonance phenomenon of such systems. This is an advantage over the existing methods, which require additional damping techniques. Moreover, the proposed vector control strategy is able to fully decouple the direct (d) and quadrature (q) components of the current in a rotating reference frame. The design procedure comprises a constrained optimization-based loop shaping. It utilizes the multi-input multi-output (MIMO) nonparametric model of the system along with a high-order linearly parameterized MIMO controller to form an open-loop transfer function matrix. Minimizing the second norm of the error between the open-loop transfer function matrix and a desired one, the coefficients of the controller are optimally determined. Conducting several reference tracking scenarios, the performance of the proposed vector controller is evaluated both by means of time-domain simulation studies in MATLAB/Simulink and experimental results.

Modular converter architecture for medium voltage ultra fast EV charging stations: Dual half-bridge-based isolation stage

Abstract: The concept of ultra fast charging of Electric Vehicles (EVs) is expected to contribute significantly to their widespread utilization in long-distance travels. Towards this direction, emerging power electronic topologies will be the key components of the developed charging infrastructures. Lately, a novel converter architecture has been proposed for such a purpose. The latter is based on a Cascaded H-Bridge (CHB) converter with integrated battery energy storage systems, which play the role of a buffer in such a power demanding application. This paper is focusing on the isolated DC/DC conversion stage, which is needed for the achievement of the high charging currents. The dual half-bridge (DHB) converter is chosen, which fulfills several requirements for the studied application. The soft switching operation of the converter under wide input-output voltage variations is discussed. Moreover, a current controller is designed, capable of dealing with the topology-specific challenges. Finally, the development of a down-scaled laboratory prototype is described and experimental results are provided.