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

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

Energy storage systems (ESSs) are enabling technologies for well-established and new applications such as power peak shaving, electric vehicles, integration of renewable energies, etc. This paper presents a review of ESSs for transport and grid applications, covering several aspects as the storage technology, the main applications, and the power converters used to operate some of the energy storage technologies. Special attention is given to the different applications, providing a deep description of the system and addressing the most suitable storage technology. The main objective of this paper is to introduce the subject and to give an updated reference to nonspecialist, academic, and engineers in the field of power electronics.

Energy Storage Systems for Transport and Grid Applications

The issue of renewable energy is becoming significant due to increasing power demand, instability of the rising oil prices and environmental problems. Among the various renewable energy sources, fuel cell is gaining more popularity due to their higher efficiency, cleanliness and cost-effective supply of power demanded by the consumers. This paper presents a comprehensive review of different fuel cell technologies with their working principle, advantages, disadvantages and suitability of applications for residential/grid-connected system, transportation, industries and commercial applications. Development of mathematical model of fuel cell required for simulation study is discussed. This paper also focuses on the necessity of a suitable power-conditioning unit required to interface the fuel cell system with standalone/grid applications.

A review on fuel cell technologies and power electronic interface

Application of Response Surface Methodology to Robust Design of BLDC Motor

This paper proposes a design technique of permanent magnet synchronous motor (PMSM) using hybrid type permanent magnet (PM) to consider simple structure and irreversible demagnetization. Here, the hybrid type PM is defined as using both of neodymium permanent magnet (Nd-PM) and ferrite permanent magnet (Fe-PM) in a rotor. For developing a competitive motor in terms of performance per manufacturing cost, firstly, the hybrid type PMSM is suggested by designing simple configuration considering magnetic property of Nd-PM and Fe-PM. Secondly, in this study, irreversible demagnetization of Fe-PM occurring by reversed magnetic field of Nd-PM is analyzed, when a rotor exists with and without a stator, and based on this analysis, a technique for avoiding the irreversible demagnetization phenomenon is proposed in order to improve reliability of hybrid type PMSM. Finally, the prototype based on proposed design is developed for evaluating the performance and demagnetization phenomenon through experiment.

Design technique for PMSM with hybrid type permanent magnet

The energy industry, primarily based on the use of fossil fuels (e.g., coal and oil) is rapidly shifting toward renewable energy for securing sustainable resources. Thus, preparing for large wind power ramp events is essential to retain reliable and secure power systems. This study proposed a new statistical approach to predict wind power ramp events, and evaluated the performance of prediction. The empirical data, which is the observed wind power output data and wind speed data from Taebaek (South Korea) were used for analyzing ramp events and for evaluation. Based on the data analysis, a practical metric for evaluating the performance of wind power ramp events forecasting was developed and presented in detail. Notably, the accuracy of forecasting was evaluated through various metrics, whereas the normalized mean absolute error (NMAE) analysis demonstrated ≤ 10% values for all the analyzed months. In addition, a system review was conducted to check if the methodology suggested in this study has helped enhance the security of power systems. The results show that evaluating and considering the ramp events can improve the accuracy of wind power output forecasting which can secure the smart energy systems.

/pdf/a-practical-metric-to-evaluate-the-ramp-events-of-wind-3qpboybi.pdf

A Practical Metric to Evaluate the Ramp Events of Wind Generating Resources to Enhance the Security of Smart Energy Systems

In this paper, low frequency current ripples generated by propulsion motor and three-phase inverter for motor drive in Fuel Cell Electric Vehicles (FCEVs) is analyzed and its effects are considered on the performance of fuel cell stack. For more accurate analysis, the actual driving pattern based on urban transit buses in the Manhattan is modeled and used to the entire system. The informative simulation results are provided to certify the validity of the theoretical analysis.

Analysis of low frequency current ripples in Fuel Cell Electric Vehicles considering driving conditions

This paper studies the dynamic irreversible demagnetization characteristics of an interior permanent magnet (PM) brushless DC motor with a stator turn fault. A new algorithm, which is a finite element method (FEM) combined with a line voltage equation of the motor, is developed to analyze irreversible demagnetization under dynamic and transient states and considers a stator turn fault. The input current, circulating current, magnetic distribution characteristics, and operating property of the PM, including the irreversible demagnetization in the fault state, are analyzed using this algorithm by considering the magnetic saturation effect. The feasibility of the proposed method confirmed from the analysis results is verified via an experiment. Through this fault analysis, we can accurately check the fault phenomena of a PM motor against the demagnetization fault for fault prevention.

/pdf/dynamic-analysis-algorithm-of-irreversible-demagnetization-2qvdyflwz2.pdf

Jin Hur

Papers

Application of Response Surface Methodology to Robust Design of BLDC Motor

Design technique for PMSM with hybrid type permanent magnet

A Practical Metric to Evaluate the Ramp Events of Wind Generating Resources to Enhance the Security of Smart Energy Systems

Analysis of low frequency current ripples in Fuel Cell Electric Vehicles considering driving conditions

Dynamic Analysis Algorithm of Irreversible Demagnetization of IPM-type Brushless DC Motor by Stator Turn Fault