There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

This paper reviews the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in electric vehicles and hybrids. Charger systems are categorized into off-board and on-board types with unidirectional or bidirectional power flow. Unidirectional charging limits hardware requirements and simplifies interconnection issues. Bidirectional charging supports battery energy injection back to the grid. Typical on-board chargers restrict power because of weight, space, and cost constraints. They can be integrated with the electric drive to avoid these problems. The availability of charging infrastructure reduces on-board energy storage requirements and costs. On-board charger systems can be conductive or inductive. An off-board charger can be designed for high charging rates and is less constrained by size and weight. Level 1 (convenience), Level 2 (primary), and Level 3 (fast) power levels are discussed. Future aspects such as roadbed charging are presented. Various power level chargers and infrastructure configurations are presented, compared, and evaluated based on amount of power, charging time and location, cost, equipment, and other factors.

/pdf/review-of-battery-charger-topologies-charging-power-levels-85yy2igx2w.pdf

Review of Battery Charger Topologies, Charging Power Levels, and Infrastructure for Plug-In Electric and Hybrid Vehicles

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

This work is devoted to review and analyze the most relevant characteristics of multilevel converters, to motivate possible solutions, and to show that we are in a decisive instant in which energy companies have to bet on these converters as a good solution compared with classic two-level converters. This article presents a brief overview of the actual applications of multilevel converters and provides an introduction of the modeling techniques and the most common modulation strategies. It also addresses the operational and technological issues.

/pdf/the-age-of-multilevel-converters-arrives-izieu77jn6.pdf

The age of multilevel converters arrives

In this paper, the authors present a detailed study and analysis of a series resonant converter topology operating in quasi-resonant mode The dc-to-ac converter is used to convert the solar energy obtained from a photovoltaic field into an ac current Theoretical study based on the state-plane method is completed and sets of static characteristics curves for all operating modes are obtained A general design methodology is elaborated which permits the determination of the constraints on the semiconductors and reactive components Finally, a performance analysis of the converter feeding different types of loads (utility, linear and nonlinear loads), and a harmonic analysis of different waveforms based on simulation and experimental results are presented

High-performance soft-commutated converter for solar energy conversion

Wireless power transfer (WPT) system is a promising candidate for charging many electrical devices and daily home appliances. Most widely used WPT techniques are inductive coupling based on magnetic fields, and magnetic resonant inductive coupling, which include a resonant circuit in transmitter and receiver coils. In this paper, numerical and analytical analysis of short-range inducting coupling rectangular coils WPT is presented. A numerical methodology based on a three-dimensional discontinuous Galerkin time-domain (DGTD) finite element method is developed to estimate the electromagnetic propagation around WPT rectangular coils. The proposed approach leads to simulations that are fast, robust and accurate, this being the result of a local discretization strategy of the full-wave time-domain Maxwell’s equations on unstructured tetrahedral meshes that is easy to parallelize. The stability of the overall numerical scheme is obtained using an up-wind numerical flux, an implicit second-order accurate time integration scheme, and Whitney basis functions. The numerical methodology is verified based on problems with analytical methods.

Analyzing Rectangular Coil Wireless Power Transfer Based on Time Domain Discontinue Galerkin Method

With seven switching devices and two capacitors, the configuration of PEC9 has significantly decreased the number of ingredients in a creative topology. By proper regulation of the PEC9, this inverter provides various levels of voltage under a faulty switch state, which is the most prominent feature of such inverters. In this paper, an ultra-local mode control (ULM) based on single input interval type-2 (SIIT2) fuzzy logic control (FLC) is proposed in a model-free framework to stabilize the inverter output without the model identification. The control structure is divided into two sections: i) a ULM controller is adopted to meet the primary control requirements of the system operation while an extended observer error (ESO) is embedded to estimate the unknown uncertainty included in the inverter, ii) a supplementary SIT2-FLC controller is established to decrease the ESO error and improve the performance of PEC9 operation accordingly. The time-domain outcomes are provided and discussed to appraise the simplicity of control design and superior feasibility of the suggested scheme than the state-of-the-art approaches.

A Robust Ultra-Local Model Control with DC Capacitor Voltage-Balancing for PEC9 Inverter

Modeling and Simulation of Power Electronics and Drives using MATLAB/Simulink

In this paper, a microgrid based on solar photovoltaic (PV) array and a battery energy storage (BES) is presented, which operates in an islanded mode and the grid connected mode It changes the mode of operation seamlessly, while supplying uninterrupted power to the load A cascaded SOGI (Second-Order-Generalized-Integrator) based control is used in GCM The cascaded SOGI is used to extract the fundamental component of the nonlinear load current A PV array power feed-forward component is used for improving its system dynamics An optimal power from the solar PV array is acquired by using an I&C (Incremental Conductance) technique In IM, a voltage control scheme is utilized, which controls the frequency and voltage at point of common coupling (PCC) The efficacy of cascaded SOGI based technique is demonstrated through test results at various conditions such as vaying load, changing solar irradiance and transition between the modes of operation

Kamal Al-Haddad

Papers

High-performance soft-commutated converter for solar energy conversion

Analyzing Rectangular Coil Wireless Power Transfer Based on Time Domain Discontinue Galerkin Method

A Robust Ultra-Local Model Control with DC Capacitor Voltage-Balancing for PEC9 Inverter

Modeling and Simulation of Power Electronics and Drives using MATLAB/Simulink

Control of Single-Phase Solar PV-BES Microgrid