This paper proposes a power converter architecture for the implementation of an ultrafast charging station for electric vehicles (EVs). The versatile converter topology is based on the concept of the power electronic transformer. For the direct transformerless coupling to the medium-voltage grid, a cascaded H-bridge (CHB) converter is utilized. On the level of each submodule, integrated split battery energy storage elements play the role of power buffers, reducing thus the influence of the charging station on the distribution grid. The power interface between the stationary split storage stage and the EV batteries is performed through the use of parallel-connected dual-half-bridge dc/dc converters, shifting the isolation requirements to the medium-frequency range. By choosing several different submodule configurations for the parallel connection, a multiport output concept is achieved, implying the ability to charge several EVs simultaneously without the use of additional high-power chargers. All possible charging station operating modes among with the designed necessary control functions are analyzed. The state-of-charge self-balancing mode of the delta-connected CHB converter is also introduced. Finally, the development of a downscaled laboratory prototype is described, and preliminary experimental results are provided.

A Modular Multiport Power Electronic Transformer With Integrated Split Battery Energy Storage for Versatile Ultrafast EV Charging Stations

https://hal.archives-ouvertes.fr/hal-01342560/document

From static output feedback to structured robust static output feedback: A survey

Brief paper: Fixed-order H∞ controller design for nonparametric models by convex optimization

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.

Multivariable Control of Single-Inductor Dual-Output Buck Converters

Robust and optimal control of AC machines

A new method for robust ﬁxed-order H∞ controller design by convex optimization for multivariable systems is investigated. Linear Time-Invariant Multi-Input Multi- Output (LTI-MIMO) systems represented by a set of complex values in the frequency domain are considered. It is shown that the Generalized Nyquist Stability criterion can be approximated by a set of convex constraints with respect to the parameters of a multivariable linearly parameterized controller in the Nyquist diagram. The diagonal elements of the controller are tuned to satisfy the desired performances, while simultaneously, the oﬀ-diagonal elements are designed to decouple the system. Multimodel uncertainty can be directly considered in the proposed approach by increasing the number of constraints. A simulation example illustrates the eﬀectiveness of the proposed approach. by a simulation example on an unstable system.

/pdf/h-controller-design-for-spectral-mimo-models-by-convex-35em49sqap.pdf

H∞ Controller design for spectral MIMO models by convex optimization☆

A recent method for robust fixed-order H ∞ controller design by convex optimization proposed in [1] is investigated in this paper for the tuning of multivariable controllers. Linear Time-Invariant Multi-Input Multi-Output (LTI-MIMO) systems represented by a finite set of complex values in the frequency domain are considered. It is shown that the Generalized Nyquist Stability criterion can be approximated by a set of convex constraints with respect to the parameters of a multivariable linearly parameterized controller in the Nyquist diagram. Simultaneously, diagonal elements of the controller are tuned to satisfy the desired performances, while the off-diagonal elements decouple the system. Multimodel uncertainty can be directly considered in the proposed approach by increasing the number of constraints. An application example illustrates the effectiveness of the proposed approach.

/pdf/h-controller-design-for-spectral-mimo-models-by-convex-4ppbfwn2z4.pdf

H ∞ controller design for spectral MIMO models by convex optimization

A new approach for robust fixed-order H∞ controller design by convex optimization is proposed. Linear time-invariant single-input single-output systems represented by a finite set of complex values in the frequency domain are considered. It is shown that the H∞ robust performance condition can be approximated by a set of linear or convex constraints with respect to the parameters of a linearly parameterized controller in the Nyquist diagram. Multimodel and frequency-domain uncertainty can be directly considered in the proposed approach by increasing the number of constraints. The proposed method is compared with the standard H∞ control problem. It is shown by an example that for an unstable uncertain model, a PID controller can be designed with the proposed approach which gives better H∞ performance than a 7th order unstable controller obtained by the standard H∞ solution.

Robust fixed-order H ∞ controller design for spectral models by convex optimization

A quadratic programming approach is proposed to tune fixed-order linearly parameterized controllers for stable LTI plants represented by spectral models. The method is based on the shaping of the open-loop or closed-loop frequency functions in the Nyquist diagram. The quadratic error between a desired open loop transfer function and the actual open loop frequency function is minimized in the frequency domain subject to linear constraints guaranteeing stability and robustness margins by quadratic programming. Moreover, it is shown that the H infinity mixed sensitivity robust performance problem can be approximated by linear constraints and be integrated in the control design method. The method can directly consider multi- model as well as frequency-domain uncertainties. An application to a difficult benchmark problem illustrates the effectiveness of the proposed approach.

Gorka Galdos

Papers

Brief paper: Fixed-order H∞ controller design for nonparametric models by convex optimization

H∞ Controller design for spectral MIMO models by convex optimization☆

H ∞ controller design for spectral MIMO models by convex optimization

Robust fixed-order H ∞ controller design for spectral models by convex optimization

Robust loop shaping controller design for spectral models by quadratic programming