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

We investigated the irreversible demagnetization of a permanent-magnet (PM) brushless dc motor under an interturn fault condition. For the transient analysis, we developed a finite-element method-based demagnetization algorithm in the operating state, taking into account the circulating current flowing in the shorted turns and the freewheeling current flowing in the diode. We analyzed the magnetic distribution property, input current, circulating current, and demagnetization characteristic of the PM using this algorithm. The analysis results from the demagnetization algorithm were verified by dynamic fault experiments.

Transient Analysis of Irreversible Demagnetization of Permanent-Magnet Brushless DC Motor With Interturn Fault Under the Operating State

This paper presents a detailed comparative study of spoke type brushless dc (SPOKE-BLDC) motors due to the operating conditions and designs a new type SPOKE-BLDC with flux barriers for high torque applications, such as tractions. The current dynamic analysis method considering the local magnetic saturation of the rotor and the instantaneous current by pwm driving circuit is developed based on the coupled finite element analysis with rotor dynamic equations. From this analysis, several new structures using the flux barriers are designed and the characteristics are compared in order to reduce the large torque ripple and improve the average torque of SPOKE-BLDC. From these results, it is confirmed that the flux barriers, which are inserted on the optimized position of the rotor, have made remarkable improvement for the torque characteristics of the SPOKE-BLDC.

Design of spoke type BLDC motors with high power density for traction applications

Contemporary research has shown impetus in the diagnostics of permanent magnet (PM) type machines. The manufacturers are now more interested in building diagnostics features in the control algorithms of machines to make them more salable and reliable. A compact structure, exclusive high-power density, high torque density, and efficiency make the PM machine an attractive option to use in industrial applications. The impact of a harsh operational environment most often leads to faults in PM machines. The diagnosis and nipping of such faults at an early stage have appeared as the prime concern of manufacturers and end users. This paper reviews the recent advances in fault diagnosis techniques of the two most frequently occurring faults, namely inter-turn short fault (ITSF) and irreversible demagnetization fault (IDF). ITSF is associated with a short circuit in stator winding turns in the same phase of the machine, while IDF is associated with the weakening strength of the PM in the rotor. A detailed literature review of different categories of fault indexes and their strengths and weaknesses is presented. The research trends in the fault diagnosis and the shortcomings of available literature are discussed. Moreover, potential research directions and techniques applicable for possible solutions are also extensively suggested.

A Comprehensive Review of Winding Short Circuit Fault and Irreversible Demagnetization Fault Detection in PM Type Machines

This paper proposes a new design of a SPOKE-type permanent magnet brushless direct current (BLDC) motor by using pushing magnet. A numerical analysis is developed to calculate the maximum value of air-gap flux density. First, the analytical model of the SPOKE-type motor was established, and Laplace equations of magnetic scalar potential and a series of boundary conditions were given. Then, the analytical expressions of magnet field strength and magnet flux density were obtained in the air gap produced by ferrite permanent magnets. The developed analytical model was obtained by solving the magnetic scalar potential. Finally, the air-gap field distribution and back-electromotive force of spoke type machine was analyzed. The analysis works for internal rotor motor topologies, and either radial or parallel magnetized permanent magnets. This paper validates results of the analytical model by finite-element analysis as well as with the experimental analysis for SPOKE-type BLDC motors.

Design and Analysis of a Spoke Type Motor With Segmented Pushing Permanent Magnet for Concentrating Air-Gap Flux Density

This paper presents characteristics of a permanent magnet linear synchronous motor (PMLSM) considering lateral leakage flux and lateral displacement. In order to analyze the PMLSM with large air gap and finite width, a new three dimensional equivalent magnetic circuit network method (3D EMC) is introduced, which supplements the magnetic equivalent circuit by using numerical techniques. It can model flux ripple three-dimensionally by the teeth and slot structure of the PMLSM, and can take nonlinear magnetic phenomenon into account, which results from using the distributed magnetic circuit parameter, permeance. The analysis considering lateral flux and lateral displacement in the PMLSM which is problematic in 3D is performed using 3D EMC and is compared with the experimental value.

Jin Hur

Papers

Transient Analysis of Irreversible Demagnetization of Permanent-Magnet Brushless DC Motor With Interturn Fault Under the Operating State

Design of spoke type BLDC motors with high power density for traction applications

A Comprehensive Review of Winding Short Circuit Fault and Irreversible Demagnetization Fault Detection in PM Type Machines

Design and Analysis of a Spoke Type Motor With Segmented Pushing Permanent Magnet for Concentrating Air-Gap Flux Density

Analysis of PMLSM using three dimensional equivalent magnetic circuit network method