A new off-board electrical vehicle battery charger: topology, analysis and design

The extensive use of electric vehicles (EVs) can reduce concerns about climate change and fossil fuel shortages. One of the main obstacles to accepting EVs is the limitation of charging stations, which consists of high-charge batteries and high-energy charging infrastructure. A new transformer-less topology for boost dc-dc converters with higher power density and lower switch stress is proposed in this paper, which may be a suitable candidate for high-power fast-charging battery chargers of EVs. Throughout this paper, two operating modes of the proposed converter, continuous current mode (CCM) and discontinuous current mode (DCM), are analyzed in detail. Additionally, critical inductances and design considerations for the proposed converter are calculated. Finally, real-time verifications based on hardware-in-loop (HiL) simulation are carried out to assess the correctness of the proposed theoretical concepts

Designing controller parameters of an LPV system via design space exploration

This paper deals with the stabilizability problem of linear parameter varying (LPV) systems. It is assumed that LPV models affinely depend on time-varying uncertain and time-invariant design parameters. The uncertain parameters, their time-derivations, and design parameters belong to polygonal convex spaces. The stabilizability problem of such systems is studied. Extending the stability conditions to stabilizability conditions generally causes nonlinearity issues due to the coupling between the Lyapunov and design variables. To cope with this issue, a design space exploration algorithm (DSEA) is proposed to accurately determine the design parameters with a feasibility performance similar to stability analysis approaches. DSEA removes the undesired parts of the design subspace that cannot stabilize the model. Then, it checks the corner points of the remaining subspaces to find a stabilizing point. This procedure continues until a stabilizing point is found or the whole design subspaces are detected to be undesirable. Three hundred random LPV systems are generated to compare the feasibility performance of DSEA with existing approaches. Also, the proposed approach is used to stabilize the LPV model of a microgrid consisting of several distributed generation units and energy storage systems. The simulation results show the superiority of DSEA over the existing approaches

Stability oriented design of cyber attack resilient controllers for cooperative DC microgrids

Due to the importance of reliability and security in DC microgrids, it is essential to provide maximum resilience against cyber-attacks. However, insufficient global information in the microgrid makes it difficult to accurately identify the location of these attacks. To address these issues, this paper develops a novel resilient distributed control mechanism, which ensures average voltage regulation and proportional load sharing in DC microgrids under unknown cyber-attacks. The proposed resilient control design does not require any information regarding the nature or location of the attacks. By virtue of a graph theoretical approach and a Lyapunov-based framework, the proposed resilient distributed control strategy is designed in a way such that the system stability is always guaranteed following a comprehensive design mechanism. Finally, the robustness of the proposed resilient distributed control approach is demonstrated via simulations and validated by experimental results

Distributed control of parallel DC-DC converters under FDI attacks on actuators

The parallel connection of DC-DC converters requires the development of an appropriate control strategy that regulates load voltage and shares current amongst participating converters. This paper proposes a resilient and robust cooperative distributed control approach that simultaneously ensures voltage regulation and balanced current sharing in parallel DC-DC converters in the presence of false data injection attacks on control input channels. Based on analytical tools from network control and Lyapunov stability theory, concise stability certificates are derived. The proposed cooperative distributed control strategy guarantees resilience against unknown bounded attacks on the actuators of DC-DC converters and the robustness to uncertainties in load parameters and the physical parameters of converters. Furthermore, the control design for each converter does not require any knowledge about the number of participating converters. The detailed simulation and experimental results verify the satisfactory performance of the proposed method in voltage regulation and balanced current sharing in parallel converters, as well as resilience to bounded false data injection attacks

Robust decentralized voltage control for uncertain DC microgrids

A decentralized voltage control scheme to achieve robust stability and robust performance of islanded direct current (DC) microgrids is presented in this paper. The investigated microgrid consists of multiple distributed generation (DG) units with a general topology, each one comprising a local uncertain ZIP (constant impedance (Z), constant current (I), and constant power (P)) load. The proposed controller confers the following main advantages: 1) the design procedure is scalable, 2) it has a completely decentralized structure, 3) it prepares stability and desirable performance of the nominal closed-loop microgrid, 4) it preserves robust stability as well as robust performance of microgrid system under different sources of uncertainty, including plug-and-play (PnP) functionalities of DGs, microgrid topology changes, uncertain ZIP load, and unmodeled load dynamics, 5) every local controller is the solution of a unique convex optimization problem, resulting in the optimal performance and robustness to several different successive changes. First, a linear time-invariant (LTI) state-space model is developed for each DG subsystem with capturing disturbances, and different uncertainty sources are modeled as a new single polytope. Then, all control objectives are converted into a robust dynamic output-feedback-based controller for an LTI polytopic system with performance criterion. Finally, the obtained nonconvex problem is reduced to a linear matrix inequality (LMI) based optimization problem. Several simulation case studies are carried out in MATLAB to demonstrate the effectiveness of the proposed controller