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

Predictive maintenance in the permanent magnet synchronous motor (PMSM) is of paramount importance due to its usage in electric vehicles and other applications. Recently various deep learning techniques are applied for fault detection and identification (FDI). However, it is very hard to optimally train the deeper networks like convolutional neural network (CNN) on a relatively fewer and non-uniform experimental data of electric machines. This paper presents a deep learning-based FDI for the irreversible-demagnetization fault (IDF) and bearing fault (BF) using a new transfer learning-based pre-trained visual geometry group (VGG). A variant of ImageNet pre-trained VGG network with 16 layers is used for the classification. The vibration and the stator current signals are selected for the feature extraction using the VGG-16 network for reliable detection of faults. A confluence of vibration and current signals-based signal-to-image conversion approach is also introduced for exploiting the benefits of transfer learning. We evaluate the proposed approach on ImageNet pre-trained VGG-16 parameters and training from scratch to show that transfer learning improves the model accuracy. Our proposed method achieves a state-of-the-art accuracy of 96.65% for the classification of faults. Furthermore, we also observed that the combination of vibration and current signals significantly improves the efficiency of FDI techniques.

https://www.mdpi.com/1996-1073/13/15/3834/pdf

Detection and Identification of Demagnetization and Bearing Faults in PMSM Using Transfer Learning-Based VGG

In this study, we propose the mitigation method of a shaft voltage according to change in parasitic capacitances of a permanent magnet synchronous motor (PMSM). First, we designed the equivalent circuit taking into account all parasitic capacitances. Then, we deducted that rotor-to-winding and stator-to-rotor capacitances mainly affect the shaft voltage. The stator-to-rotor capacitance depends on the air-gap length, which directly affects output torque characteristics of the motor. In case of the rotor-to-winding capacitance, it depends on the distance from the rotor to winding, which have effects on torque ripple, but it doesn't affect average torque of the motor. Thus, rotor-to-winding capacitance is determined as a variable for mitigation of the shaft voltage. According to change in the rotor-to-winding capacitance, we obtained and compared the results of the shaft voltage, average torque, and torque ripple.

Mitigation method of the shaft voltage according to parasitic capacitance of the PMSM

Common-mode voltage by switching pattern of space vector pulsewidth modulation excites parasitic capacitance coupling in interior permanent magnet synchronous motors, and it finally causes a shaft-to-frame voltage. Among all parasitic capacitances, winding-to-rotor parasitic capacitance has the greatest effect on the shaft-to-frame voltage, which means the winding-to-rotor parasitic capacitance must be suppressed for noticeable mitigation of the shaft-to-frame voltage. This paper proposes two suppression methods by changing the stator winding-to-rotor and end winding-to-rotor capacitances. First, the modified winding shape is utilized for the suppression of stator winding-to-rotor capacitance. Second, a copper shield is applied to suppress the end winding-to-rotor parasitic capacitance. Finally, both the methods are applied together to mitigate the effect of the stator winding-to-rotor and end winding-to-rotor capacitances on the shaft-to-frame voltage.

Shaft-to-Frame Voltage Mitigation Method by Changing Winding-to-Rotor Parasitic Capacitance of IPMSM

The main purpose of this paper is to describe six-switch inverters for cost effective Switched Reluctance Motor (SRM) drive used in commercial applications. For effective utilization of the developed system, a novel direct current controlled PWM scheme is designed and implemented to produce the desired dynamic and static speed-torque characteristic. Compared with the conventional split typed asymmetric converter topology, it can minimize the entire system size and cost and can increase the efficiency. Therefore, it may pave a new way for SRM to compete with other ac motors, such as induction motors, brushless dc motors, and so on. The validity of the proposed method is verified by theoretical explanation, simulation, and experimental results.

A New Cost Effective SRM Drive using Commercial 6-Switch IGBT Modules

This paper proposes optimized design of permanent magnet synchronous motor (PMSM) using hybrid type permanent magnet (PM) for improving the output characteristics and reliability. 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. First, the optimized design of PMSM considering magnetic equivalent circuit is suggested for reducing total reluctance value of Nd-PM and Fe-PM to increase the performance of motor. As a result, parallel configuration of reluctance factors is helpful for increasing output characteristics, and it is analyzed by using a finite element method (FEM). Secondly, irreversible demagnetization of Fe-PM occurring by reversed magnetic field of Nd-PM is analyzed, in two cases of a rotor exists with and without a stator in order to improve reliability of PMSM using hybrid type PM. Finally, a prototype based on proposed design is developed for evaluating the enhanced performance.

Jin Hur

Papers

Detection and Identification of Demagnetization and Bearing Faults in PMSM Using Transfer Learning-Based VGG

Mitigation method of the shaft voltage according to parasitic capacitance of the PMSM

Shaft-to-Frame Voltage Mitigation Method by Changing Winding-to-Rotor Parasitic Capacitance of IPMSM

A New Cost Effective SRM Drive using Commercial 6-Switch IGBT Modules

Optimized design of PMSM with hybrid type permanent magnet for improving performance and reliability