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.

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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

In this paper, the characteristics of brushless dc (BLDC) motors were compared and analyzed according to the types and control methods under the inter-turn fault (ITF) condition. The shorted windings produced by the ITF were modeled by the winding function theory (WFT) based on the distributed constant circuit method. We also introduced the inductance calculated by the WFT to the voltage equation and analyzed the effect of the ITF using the characteristics of the input and output parameters. The increase rate of torque ripple, increase rate of input current, and the circulating current of the surface permanent-magnet (PM) and interior PM motors under healthy and ITF conditions were compared to determine which motor type is more efficient in preventing the ITF. We also analyzed the fault characteristics by applying the advanced angle control. In this paper, the analysis results are validated by the finite-element method and experiments.

Comparison of the Fault Characteristics of IPM-Type and SPM-Type BLDC Motors Under Inter-Turn Fault Conditions Using Winding Function Theory

In elevator drive systems, the gains of a conventional proportional-integral (PI) speed controller cannot usually be set large enough because of its mechanical resonance. Consequently, the speed control performance deteriorates. In our work described in this paper, a fuzzy logic controller (FLC) was adopted for use in elevator drive systems in order to improve the speed control performance. The proposed FLC was compared with a conventional PI controller with respect to speed dynamic responses and load torque. Simulation and experimental results demonstrated that the proposed FLC was superior over the conventional PI. This FLC can be a good solution for high-performance elevator drive systems.

Fuzzy-Logic-Based Vector Control Scheme for Permanent-Magnet Synchronous Motors in Elevator Drive Applications

This study proposes the shaft voltage mitigation method according to change in parasitic capacitances of a permanent magnet synchronous motor. To consider the shaft voltage reduction in the initial motor design process without any filter, the parasitic capacitances affecting the shaft voltage are calculated using the motor geometry parameters. Then, the shaft voltage is analyzed according to change in parasitic capacitances using the equivalent circuit model and the torque characteristic is also analyzed to effectively mitigate the shaft voltage. As a result, the rotor-to-winding is determined as an appropriate parameter to mitigate the shaft voltage among the parasitic capacitances, because it affects the shaft voltage and does not affect the output torque. Finally, the shaft voltage mitigation method according to variation of rotor-to-winding capacitance is verified by experiment.

Mitigation Method of the Shaft Voltage According to Parasitic Capacitance of the PMSM

Interturn faults (ITFs) cause significant changes in the electrical and magnetic characteristics of motors. In particular, ITFs can be the cause of serious distortions in the magnetic field of an air gap. Therefore, we develop a system matrix with an ITF for FEM simulation, which considers the nonlinearity of the ITF. Using the analysis of the magnetic characteristics of the detection coil from the FEM results, a circuit that employs the proposed diagnosis algorithm is shown to detect the phase and the location of a fault.

Diagnosis Technique Using a Detection Coil in BLDC Motors With Interturn Faults

In this paper, the fields and forces of permanent magnet linear synchronous motors (PMLSM) with segmented or skewed magnet arrangement are analyzed according to length of segment or skew. And, the effects according to the lateral overhang of magnet are investigated. For the analysis, 3-dimensional equivalent magnetic circuit network (3-D EMCN) method is used. The analysis results are compared with the experimental ones and show a reasonable agreement.

Jin Hur

Papers

Comparison of the Fault Characteristics of IPM-Type and SPM-Type BLDC Motors Under Inter-Turn Fault Conditions Using Winding Function Theory

Fuzzy-Logic-Based Vector Control Scheme for Permanent-Magnet Synchronous Motors in Elevator Drive Applications

Mitigation Method of the Shaft Voltage According to Parasitic Capacitance of the PMSM

Diagnosis Technique Using a Detection Coil in BLDC Motors With Interturn Faults

3-D analysis of permanent magnet linear synchronous motor with magnet arrangement using equivalent magnetic circuit network method