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World Electric Vehicle Journal is published by MDPI from Volume 9 issue 1 (2018). Articles in this Issue were published by The World Electric Vehicle Association (WEVA) and its member the European Association for e-Mobility (AVERE), the Electric Drive Transportation Association (EDTA), and the Electric Vehicle Association of Asia Pacific (EVAAP). They are hosted by MDPI on mdpi.com as a courtesy and upon agreement with AVERE.

Table of Contents

World Electr. Veh. J., Volume 5, Issue 2 (June 2012) , Pages 269-628

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Open AccessArticle
Torque Vectoring for Electric Vehicles with Individually Controlled Motors: State-of-the-Art and Future Developments
World Electr. Veh. J. 2012, 5(2), 617-628; https://doi.org/10.3390/wevj5020617 - 29 Jun 2012
Cited by 6 | Viewed by 422
Abstract
This paper deals with the description of current and future vehicle technology related to yaw moment control, anti-lock braking and traction control through the employment of effective torque vectoring strategies for electric vehicles. In particular, the adoption of individually controlled electric powertrains with [...] Read more.
This paper deals with the description of current and future vehicle technology related to yaw moment control, anti-lock braking and traction control through the employment of effective torque vectoring strategies for electric vehicles. In particular, the adoption of individually controlled electric powertrains with the aim of tuning the vehicle dynamic characteristics in steady-state and transient conditions is discussed. This subject is currently investigated within the European Union (EU) funded Seventh Framework Programme (FP7) consortium E-VECTOORC, focused on the development and experimental testing of novel control strategies. Through a comprehensive literature review, the article outlines the stateof- the-art of torque vectoring control for fully electric vehicles and presents the philosophy and the potential impact of the E-VECTOORC control structure from the viewpoint of torque vectoring for vehicle dynamics enhancement. Full article
Open AccessArticle
The FlexRay Implementation of By-Wire System for Electric Vehicle
World Electr. Veh. J. 2012, 5(2), 610-616; https://doi.org/10.3390/wevj5020610 - 29 Jun 2012
Viewed by 222
Abstract
In the recent years, advanced technologies of electronic devices for the communication and computer engineering have been considered to be widely implemented in the vehicle systems. Among those possible applications, the automotive network which is so-called “X-by-Wire” scheme has been developed for steering [...] Read more.
In the recent years, advanced technologies of electronic devices for the communication and computer engineering have been considered to be widely implemented in the vehicle systems. Among those possible applications, the automotive network which is so-called “X-by-Wire” scheme has been developed for steering control and braking control of the vehicles. It is known that the weight reduction of vehicle systems can decrease the power consumption in the design of electric driven vehicle by replacing the mechanical components with electronic devices. Therefore, X-by-wire system combined with fault-tolerant applications will be a trend in the automotive industry. Under the automotive circumstance, the timetrigged protocol improves the network capacity and guarantees the transmission of all safety related message. In order to ensure the safety of electronic devices, an advanced networking protocol FlexRay has been recently proposed to the design of X-by-wire system. In this paper, such an X-by-wire mechanism is developed for electric vehicle. The proposed design covers the development of a hub wheel motor driven electric vehicle and the design of both electronic control braking module and communication network. For facilitating the application usage, a FlexRay communication node is developed by using microprocessor chip Freescale MC9S12XF512. An electric vehicle is also designed by using four hub wheel type AC motors with DC motor driven braking mechanism for system testing and performance evaluation. A timescheduling scheme is proposed and configured for each of nine FlexRay nodes to fulfil the tasks of driveby- wire and brake-by-wire operations. Experimental results demonstrate the success of the proposed design. Full article
Open AccessArticle
Survey on Fault-Tolerant Vehicle Design
World Electr. Veh. J. 2012, 5(2), 598-609; https://doi.org/10.3390/wevj5020598 - 29 Jun 2012
Cited by 2 | Viewed by 270
Abstract
Fault-tolerant vehicle design is an emerging inter-disciplinary research domain, which is of increased importance due to the electrification of automotive systems. The goal of fault-tolerant systems is to handle occuring faults under operational condition and enable the driver to get to a safe [...] Read more.
Fault-tolerant vehicle design is an emerging inter-disciplinary research domain, which is of increased importance due to the electrification of automotive systems. The goal of fault-tolerant systems is to handle occuring faults under operational condition and enable the driver to get to a safe stop. This paper presents results from an extended survey on fault-tolerant vehicle design. It aims to provide a holistic view on the fault-tolerant aspects of a vehicular system. An overview of fault-tolerant systems in general and their design premises is given as well as the specific aspects related to automotive applications. The paper highlights recent and prospective development of vehicle motion control with integrated chassis control and passive and active fault-tolerant control. Also, fault detection and diagnosis methods are briefly described. The shift on control level of vehicles will be accompanied by basic structural changes within the network architecture. Control architecture as well as communication protocols and topologies are adapted to comply with the electrified automotive systems. Finally, the role of regulations and international standardization to enable fault-tolerant vehicle design is taken into consideration. Full article
Open AccessArticle
Design of Adaptive Sliding Mode Controller for Robust Yaw Stabilization of In-wheel-motor-driven Electric Vehicles
World Electr. Veh. J. 2012, 5(2), 588-597; https://doi.org/10.3390/wevj5020588 - 29 Jun 2012
Cited by 1 | Viewed by 250
Abstract
A robust yaw stability control system is designed to stabilize the vehicle yaw motion. Since the vehicles undergo changes in parameters and disturbances with respect to the wide range of driving condition, e.g., tire-road conditions, a robust control design technique is required to [...] Read more.
A robust yaw stability control system is designed to stabilize the vehicle yaw motion. Since the vehicles undergo changes in parameters and disturbances with respect to the wide range of driving condition, e.g., tire-road conditions, a robust control design technique is required to guarantee system stability. In this paper, a sliding mode control methodology is applied to make vehicle yaw rate to track its reference with robustness against model uncertainties and disturbances. A parameter adaptation law is applied to estimate varying vehicle parameters with respect to road conditions and is incorporated into sliding mode control framework. The control performance of the proposed control system is evaluated through computer simulation using CarSim vehicle model which proved to give a good description of the dynamics of an experimental in-wheel-motor-driven electric vehicle. Moreover, field tests were carried out to verify the effectiveness of the proposed adaptive sliding mode controller Full article
Open AccessArticle
Pipe Shield High-Voltage Wiring Harness
World Electr. Veh. J. 2012, 5(2), 581-587; https://doi.org/10.3390/wevj5020581 - 29 Jun 2012
Viewed by 278
Abstract
The conventional high-voltage wiring harness for HEV is composed of wires and plastic protectors. Because of low heat transfer of the plastic protector, the larger sized wire is needed for high-voltage wiring harness to reduce the Joule-heat loss. Furthermore, high design cost and [...] Read more.
The conventional high-voltage wiring harness for HEV is composed of wires and plastic protectors. Because of low heat transfer of the plastic protector, the larger sized wire is needed for high-voltage wiring harness to reduce the Joule-heat loss. Furthermore, high design cost and long lead-time are required to make the mould for a new or modified protector. We have developed the pipe shield wiring harness to eliminate these problems. The pipe shield wiring harness is already in mass-production for Honda CIVIC HYBRID, INSIGHT, CR-Z and FIT HYBRID etc. In this paper, we explain the characteristics and the structure of the conventional high-voltage wiring harness against those of the innovative pipe shield wiring harness. Heat resistance against an external source, weight reduction, simplification of wiring harness assembly and sheath design, electromagnetic shielding performance, and resistance to stone chipping, are described. Full article
Open AccessArticle
Effective Thermal Simulation of Power Electronics in Hybrid and Electric Vehicles
World Electr. Veh. J. 2012, 5(2), 574-580; https://doi.org/10.3390/wevj5020574 - 29 Jun 2012
Viewed by 242
Abstract
Thermal management is critical in development of hybrid and electric vehicles since they contain multiple high-density power modules that require compact integration and effective cooling. During operation the power modules generate large amounts of heat leading to significant temperature increases and thermal gradients [...] Read more.
Thermal management is critical in development of hybrid and electric vehicles since they contain multiple high-density power modules that require compact integration and effective cooling. During operation the power modules generate large amounts of heat leading to significant temperature increases and thermal gradients inside dies and across the packages. Electro-thermal simulation is needed to choose the best operating regime to meet the thermal and electrical requirements. However, this is usually computationally expensive. One effective method is to develop a compact but accurate thermal model to capture the thermal physics that can be used in the system-level electro-thermal model. In this paper an effective Model Order Reduction (MOR) is developed that drastically reduces the number of Degree of Freedoms (DOFs) of the original large-dimension ODE system. Finite Element Analysis (FEA)/ Computational Fluid Dynamics (CFD) simulation is first conducted to find the optimal pin-fin to rear channel ratio and the optimal pin fin shape that gives lowest peak temperature and pressure drop. The convective heat transfer coefficients exacted from FEA/CFD is input to the MOR model. The MOR model is then applied to a converter assembly, and results show that it can reduce the computation time from 2 hours to 1 second with reasonable error compared to the FEA/CFD predictions. The MOR thermal model can be further coupled with electrical circuit models to form a system model to predict the temperature profile and the power modules’ electrical transient performance. Full article
Open AccessArticle
Quasi-Resonant Flyback DC/DC Converter Using GaN Power Transistors
World Electr. Veh. J. 2012, 5(2), 567-573; https://doi.org/10.3390/wevj5020567 - 29 Jun 2012
Viewed by 264
Abstract
Quasi-resonant flyback converter is realized with the aim to demonstrate the topology feasibility using the normally-on switching behaviour of the gallium nitride (GaN) power transistor. Reference converters utilize GaN and silicon-based MOSET as the switching devices to compare the electric characteristics, and power [...] Read more.
Quasi-resonant flyback converter is realized with the aim to demonstrate the topology feasibility using the normally-on switching behaviour of the gallium nitride (GaN) power transistor. Reference converters utilize GaN and silicon-based MOSET as the switching devices to compare the electric characteristics, and power losses. Quasi-resonant technology offers reduced turn-on losses, resulting in increased efficiency and lower device temperature. The turn-on losses dominate the power losses as the switching frequency of the power supply increases. The combined advantages of gate charge and on-resistance for GaN in the 60 watt reference converter leads to improve the turn-off conduction loss. GaN based power converter provides up to 7.02% improved efficiency over silicon based MOSFETs. The converter performance improvement opens the possibility of fully exploiting the wide advantages of GaN transistors in power electronic application. Full article
Open AccessArticle
Experimental Investigations on Voltage Stability in Multilevel Power Nets
World Electr. Veh. J. 2012, 5(2), 556-566; https://doi.org/10.3390/wevj5020556 - 29 Jun 2012
Cited by 1 | Viewed by 215
Abstract
In recent years, more and more components in vehicles have been electrified in order to improve the safety and comfort of the passengers as well as the driving performance. Owing to these developments, it has become increasingly difficult to guarantee the voltage stability [...] Read more.
In recent years, more and more components in vehicles have been electrified in order to improve the safety and comfort of the passengers as well as the driving performance. Owing to these developments, it has become increasingly difficult to guarantee the voltage stability within the 12V as well as the high voltage power bus. However, a new degree of freedom arises, as the two power nets are connected in order to exchange energy. As a consequence, they are able to stabilize their voltage reciprocally. This paper deals with the analysis of how two voltage levels can be coupled actively in order to stabilize their voltages in power demanding situations. A power net test bench consisting of a 12V power net and a high voltage power net is built. In the 12V power net, original chassis and wiring harness are used in order to achieve the most realistic behavior. Furthermore, there are two control modes presented. In the power control mode, the power flow is increased preventively when the prediction model detects a critical situation that is likely to occur in the near future. In the voltage control mode, the voltage controller of the DC chopper converter is used to stabilize the power net voltage in real time. Both control methods can easily be implemented into a universal power distribution management system. The voltage control mode is experimentally investigated at the power net test bench and it is shown that the minimum voltage in very power-consuming driving situations is increased by about 1.5V per 1000W of applied power supplied by the DC chopper converter. Full article
Open AccessArticle
Weight Reduction Design of In-Wheel type Motor For Power density Improvement
World Electr. Veh. J. 2012, 5(2), 550-555; https://doi.org/10.3390/wevj5020550 - 29 Jun 2012
Viewed by 224
Abstract
This paper deals with the weight reduction design of In-Wheel type motor for high power density. Accordingly, characteristic and weight of the motor caused by modifying reduction gear ratio are examined. Weight of motor is minimized by modulating the ratio of stack length [...] Read more.
This paper deals with the weight reduction design of In-Wheel type motor for high power density. Accordingly, characteristic and weight of the motor caused by modifying reduction gear ratio are examined. Weight of motor is minimized by modulating the ratio of stack length and external diameter of stator. Then, In-Wheel motor geometry based on the prototype is optimized to get the determined parameters using response surface methodology (RSM) and Finite Element Method (FEM). Optimal design of core usage in rotor is conducted for minimizing weight of motor which has identical characteristic to the prototype. Characteristic analysis is conducted by using equivalent circuit analysis of PM type motor. Through the presented weight of In-Wheel type motor, total weight is reduced to 25%, and power density is improved to 57% from the prototype motor. Full article
Open AccessArticle
Why the Induction Motor Could be the Better Choice for Your Electric Vehicle Program
World Electr. Veh. J. 2012, 5(2), 546-549; https://doi.org/10.3390/wevj5020546 - 29 Jun 2012
Cited by 1 | Viewed by 236
Abstract
Low weight and high power density is a main focus in electro mobility. The most common traction motors for vehicle applications are synchronous motors or induction motors whereas synchronous motors are preferred because of their advantage regarding power density and weight. But each [...] Read more.
Low weight and high power density is a main focus in electro mobility. The most common traction motors for vehicle applications are synchronous motors or induction motors whereas synchronous motors are preferred because of their advantage regarding power density and weight. But each of the motor concepts has its advantages and disadvantages. In this paper it is shown that Siemens has managed to increase the power density of induction motors and simultaneously reduced the main disadvantage of the induction motor by optimizing some parts of the motor. With this adaption it is possible to reduce the weight and as a result of this defining parameter the induction motor has in summary more advantages compared with the synchronous motor. Therefore it can be the better choice for electro mobility. Full article
Open AccessArticle
Condition Monitoring Sensor for Electric Vehicle Motor and Generator Insulation Systems
World Electr. Veh. J. 2012, 5(2), 541-545; https://doi.org/10.3390/wevj5020541 - 29 Jun 2012
Viewed by 267
Abstract
Electric vehicle (EV) motors are subject to extreme and variable loads, resulting in degradation of winding insulation due to high temperatures. This paper describes research on a new conductive composite sensor, which uses insulation resin as a matrix of the sensor element. The [...] Read more.
Electric vehicle (EV) motors are subject to extreme and variable loads, resulting in degradation of winding insulation due to high temperatures. This paper describes research on a new conductive composite sensor, which uses insulation resin as a matrix of the sensor element. The sensor, embedded in the windings of EV motors, will provide data on remaining design life of the insulation based on actual vehicle operational and environmental conditions. Improved condition monitoring of the insulation systems of high-performance EV motors can reduce in-use failures by identifying prematurely degraded insulation systems, and providing data for quality improvement programs. Full article
Open AccessArticle
Multifunctional Optimal Design of Axial-Flux Permanent Magnet Wheel Motors for Light Electric Vehicles
World Electr. Veh. J. 2012, 5(2), 533-540; https://doi.org/10.3390/wevj5020533 - 29 Jun 2012
Viewed by 236
Abstract
This paper presents a systematic approach of optimal design for an axial-flux permanent magnet wheel motor to have high torque density for light electric vehicles. First, the winding type and the numbers of slots and poles are determined at the stage of preliminary [...] Read more.
This paper presents a systematic approach of optimal design for an axial-flux permanent magnet wheel motor to have high torque density for light electric vehicles. First, the winding type and the numbers of slots and poles are determined at the stage of preliminary design. A magnetic circuit model with an effective air-gap distribution is then established for sensitivity analysis and multifunctional optimization. Finally, the finite element analysis is performed for verifying and refining the motor with the best torque density to fulfill design specifications. The theory of maximum torque per ampere is also applied to estimate the torque and power versus speed curves of the resulting wheel motor before it is fabricated. Full article
Open AccessArticle
Torsional Resonance Noise Reduction by Motor Torque Phase Adjustment
World Electr. Veh. J. 2012, 5(2), 527-532; https://doi.org/10.3390/wevj5020527 - 29 Jun 2012
Viewed by 191
Abstract
A Hybrid Vehicle (HEV) and an Electric Vehicle (EV) are some of solutions to improve efficiency of a cruse and to reduce CO2 gas by regenerative breaking and operating the engine in optimum condition. It is requested to decrease the motor size and [...] Read more.
A Hybrid Vehicle (HEV) and an Electric Vehicle (EV) are some of solutions to improve efficiency of a cruse and to reduce CO2 gas by regenerative breaking and operating the engine in optimum condition. It is requested to decrease the motor size and to increase the maximum torque for minimizing the driving units. For these purposes permanent magnet applied motors have been commonly used recently. The motor driving systems of HEV or EV must operate at variable speed ranges of up to 1:5. For this large range, Silent and smooth operations are desirable and important. Skew method is often adopted to ensure smooth start and stop and silent operation by reducing the torque ripple. But it possibly causes noise and vibration of the motor. This paper describes the mechanism of torsional resonance noise and vibrations arising from the skew method and the countermeasure to decrease them. Full article
Open AccessArticle
Efficiency Improvements of Electric Machines for Automotive Application
World Electr. Veh. J. 2012, 5(2), 520-526; https://doi.org/10.3390/wevj5020520 - 29 Jun 2012
Viewed by 229
Abstract
Different costs effective and high efficiency methods for improving the main performances of tooth concentrated windings are presented. Using these simple techniques, the sub- and high winding space harmonics clearly can be reduced. Different PM machines for steering and also for hybrid electric [...] Read more.
Different costs effective and high efficiency methods for improving the main performances of tooth concentrated windings are presented. Using these simple techniques, the sub- and high winding space harmonics clearly can be reduced. Different PM machines for steering and also for hybrid electric vehicle and battery electric vehicle applications are designed and analysed. The investigated PM machines show good performances. Full article
Open AccessArticle
Making the Impossible, Possible – Overcoming the Design Challenges of In Wheel Motors
World Electr. Veh. J. 2012, 5(2), 514-519; https://doi.org/10.3390/wevj5020514 - 29 Jun 2012
Cited by 1 | Viewed by 275
Abstract
For many, in wheel motors offer a panacea for vehicle design. However history shows the delivery of an acceptable in wheel motor is a deeply challenging task which is dedicated to understanding aggressive torque and speed requirements behind demands on vehicle performance such [...] Read more.
For many, in wheel motors offer a panacea for vehicle design. However history shows the delivery of an acceptable in wheel motor is a deeply challenging task which is dedicated to understanding aggressive torque and speed requirements behind demands on vehicle performance such as high speeds or sustained hill climb, and even aggressive driving, all of which are allowed by delivery of high continuous torque; limited in wheel packaging space, harsh environment, and safety requirements. Protean Electric is entirely focussed on overcoming these challenges and believes that, with its novel technology, it has delivered a product that will allow vehicle manufactures to exploit the benefits of in wheel motors. Protean’s in wheel solution is based on a direct drive, permanent magnet brushless machine with an outer rotor. High torque is delivered from a space envelope based on high ratio between the motor radius and axial length and the key to maintaining this high continuous torque is effective thermal management of the motor. Power electronics together with control circuitry is integrated into the motor architecture, while the wheel bearing provides the mounting point for the motor. This paper offers a holistic view of an in wheel motor design with special attention to overcoming the design challenges presented by harsh operating environments, high performance demands and safety aspects. Full article
Open AccessArticle
Electric Wheel Hub Motor with High Recuperative Brake Performance in Automotive Design
World Electr. Veh. J. 2012, 5(2), 510-513; https://doi.org/10.3390/wevj5020510 - 29 Jun 2012
Viewed by 312
Abstract
The entire drive integration in the wheels of electric cars enables completely new vehicle drive train concepts and liberties with the interior design. Central motor, external gearing, differentials, axels and drive-shafts are no longer required, which leads to an enormous gaining of free [...] Read more.
The entire drive integration in the wheels of electric cars enables completely new vehicle drive train concepts and liberties with the interior design. Central motor, external gearing, differentials, axels and drive-shafts are no longer required, which leads to an enormous gaining of free space for the passenger compartment or other car components. Fully new car concepts and designs will become feasible. As well it can help to reduce weight and costs and increases the efficiency of the whole drive system. In addition wearout and maintenance expenditure are reduced to a minimum. Decentralized electric drives also enable new functionalities mainly concerning vehicle dynamics. This aspect counts especially for wheel hub motors because of the direct access to the wheels without any component in between. Another significant advantage is that direct drives in general are not prone to oscillations during load changes comparing to central drives with transmission gear, coupling and drive-shaft. In this article a review on the development of a wheel hub motor is given that is designed to substitute the friction brake on the rear axle. This demand special thought towards a system that accelerates and decelerates. High torque and power densities are achieved. Furthermore it is designed to be use in typical automotive conditions and vicinities. Indisputable a wheel hub motor adds more weight to the rim. Hence the impact of the increase of the unsprung masses is discussed in this article. Full article
Open AccessArticle
Electromechanical Components and its Energy Saving Design Strategy in PHEV Powertrain
World Electr. Veh. J. 2012, 5(2), 501-509; https://doi.org/10.3390/wevj5020501 - 29 Jun 2012
Viewed by 211
Abstract
This paper presents advanced Compact Hybrid Planetary Transmission Drive (CHPTD) as a solution for the plug-in hybrid electric vehicle (PHEV). Proper architecture and elements were designed to achieve the functions of PHEV. The parameters of powertrain were adjusted and optimized by simulation. Two [...] Read more.
This paper presents advanced Compact Hybrid Planetary Transmission Drive (CHPTD) as a solution for the plug-in hybrid electric vehicle (PHEV). Proper architecture and elements were designed to achieve the functions of PHEV. The parameters of powertrain were adjusted and optimized by simulation. Two basic control strategies were selected and analyzed to achieve minimum energy consumption and the proper operation range of battery state of charge (SOC). The very effective operation of the improved powertrain was proved by tests in different driving cycles regarding the traffic both in city and suburb area. The advantage of planetary transmission, which is power summing mechanical unit, was obtained by the proper design and the control of innovative high energy saving electromagnetic clutch-brake device based on classic dual-diaphragm spring system, which also permits to apply multi-speed additional automatic mechanical transmission. Full article
Open AccessArticle
Efficiency Improvement of Regenerative Energy for an EV
World Electr. Veh. J. 2012, 5(2), 494-500; https://doi.org/10.3390/wevj5020494 - 29 Jun 2012
Cited by 1 | Viewed by 356
Abstract
Electric Vehicles (EVs) and various Hybrid Electric Vehicles (HEVs) have been attracting a lot of attention for environmental issues and energy crisis. One of advantages of using foregoing vehicles is charging energy by the regenerative brake. The running distance by one electric charge [...] Read more.
Electric Vehicles (EVs) and various Hybrid Electric Vehicles (HEVs) have been attracting a lot of attention for environmental issues and energy crisis. One of advantages of using foregoing vehicles is charging energy by the regenerative brake. The running distance by one electric charge is increased a lot by the regenerative brake. However, the absorbed capacity of the regenerative energy is limited because of the motor capacity and the current limit of the battery. As a result not only the regenerative electric brake but also the mechanical brake must be used. This becomes serious issue in the heavy weight vehicle such as the bus and the truck, the effectiveness of EV/HEV is not obtained. To increase the regenerative energy, the large motor and the battery are requested, however, it is very difficult because of the cost and the limit of the inverter capacity. In this paper, it is verified that the regenerative energy is increased by improving a braking method, averaging the deceleration, without changing the power train system. The proposed method is experimentally evaluated by i-MiEV on the dynamo system, and increases the regenerative energy to 18%. Full article
Open AccessArticle
Analysis of the Fault Tolerance of a Switched Reluctance Machine with Distributed Inverter
World Electr. Veh. J. 2012, 5(2), 482-493; https://doi.org/10.3390/wevj5020482 - 29 Jun 2012
Viewed by 197
Abstract
This paper analyzes how distributed inverters can further increase the fault tolerance of switched reluctance traction drives. The drive under investigation is an outer-rotor direct-drive switched reluctance machines (SRM) for railway traction. The phases of SRMs are magnetically and to a certain extend [...] Read more.
This paper analyzes how distributed inverters can further increase the fault tolerance of switched reluctance traction drives. The drive under investigation is an outer-rotor direct-drive switched reluctance machines (SRM) for railway traction. The phases of SRMs are magnetically and to a certain extend electrically decoupled. Hence, in case of a fault inside a phase, the remaining phases can continue operation with reduced power. With the distributed inverter concept at hand, each coil of a phase is excited by its own modular inverter. This increases the redundancy, simplifies integration of machine and inverter, and enables a new degree of freedom regarding the control of the machine. Especially for electric drives used in railway traction or electric vehicles, redundancy avoids all the inconveniences of a standstill in case of a fault, enabling a so-called limp home capability. This paper shows, how open- and short-circuit faults of single coils or modules of the proposed drive influence average torque, torque ripple, and noise and vibration. Therewith, it will be shown that with the SRM and the distributed inverter it is possible to continue operation in case of the analyzed faults. Full article
Open AccessArticle
A High Efficient Energy Converter for a Hybrid Vehicle Concept
World Electr. Veh. J. 2012, 5(2), 475-481; https://doi.org/10.3390/wevj5020475 - 29 Jun 2012
Cited by 3 | Viewed by 231
Abstract
This publication deals with the concept, the explanation, the development and the actual measurement results of a free-piston linear generator (FPLG). The free-piston linear generator is able to convert chemical energy into electrical energy by using a combustion process. In this publication the [...] Read more.
This publication deals with the concept, the explanation, the development and the actual measurement results of a free-piston linear generator (FPLG). The free-piston linear generator is able to convert chemical energy into electrical energy by using a combustion process. In this publication the function and the characteristics of the free-piston linear generator will be explained first. Then the surrounding system and its effects on the FPLG are explained. This is important to understand the effect of every subsystem to the FPLG. In the next step the development based of the three base components, the gas spring [7], the linear generator [4] and the combustion [6] will be explained. Each chapter includes actual measurement results generated on a purpose-built test bench. At the end of the publication the current situation of the FPLG development and the further steps are presented. Full article
Open AccessArticle
A Dry Clutch Control Algorithm for AMT Systems in a Parallel Hybrid Electric Bus
World Electr. Veh. J. 2012, 5(2), 469-474; https://doi.org/10.3390/wevj5020469 - 29 Jun 2012
Viewed by 230
Abstract
A clutch is a mechanical device which provides engine torque to the drive shaft of a vehicle. A dry clutch control for AMT (Automated Manual Transmission) systems has been an important issue to improve fuel economy and drivability in hybrid electric systems. In [...] Read more.
A clutch is a mechanical device which provides engine torque to the drive shaft of a vehicle. A dry clutch control for AMT (Automated Manual Transmission) systems has been an important issue to improve fuel economy and drivability in hybrid electric systems. In this paper, we propose a dry clutch control system to apply to the parallel hybrid electric bus. In order to analysis dynamic performance of the target vehicle, a vehicle dynamic model including engine, clutch, motor, transmission and vehicle is designed. For gear shifting simulation, the shifting maps for the hybrid electric bus are applied from the analysis results of DP (Dynamic Programming) theory that is one of the optimal control methods. The shifting maps consist of a pure electric mode and a hybrid electric mode calculated by using driving cycles for commercial vehicles. From vehicle dynamic equations, the control algorithm for a dry clutch is organized by using feedback loops based on the value of an engine, a clutch speed, a clutch release travel and an estimated clutch torque. Simulations are performed to analyze the dynamic performance of the proposed clutch control system during gear shifting. As a result, the vehicle model with the designed clutch controller compares to one with only the lockup controller in energy dissipation during gear shifting. Full article
Open AccessArticle
Traction Control Method of Hybrid Electric Vehicle based on Multi-Objective Dynamic Coordination Control
World Electr. Veh. J. 2012, 5(2), 460-468; https://doi.org/10.3390/wevj5020460 - 29 Jun 2012
Viewed by 228
Abstract
The control method of the conventional traction control system on split-μsurfaces improves vehicle acceleration performance, but influences its stability performance. To solve this problem, a hierarchical traction control system for ISG hybrid electric vehicles based on multi-objective dynamic coordination control (MHEVTCS) is proposed. [...] Read more.
The control method of the conventional traction control system on split-μsurfaces improves vehicle acceleration performance, but influences its stability performance. To solve this problem, a hierarchical traction control system for ISG hybrid electric vehicles based on multi-objective dynamic coordination control (MHEVTCS) is proposed. In the upper level controller, a target driving torque calculating strategy based on dynamical sliding mode control is developed. In the lower level controller, such strategies as multi-objective dynamic coordination control strategy, brake torque control strategy based on an inverse model, target engine torque design strategy and torque dynamic coordinate control strategy are proposed. Detailed simulation and hardware-in-loop experiment results show that slipping wheels are controlled quickly, accurately and smoothly by MEHVTCS. MHEVTCS solves the problem of merely pursuing acceleration performance and neglecting stability performance of conventional traction control system. Full article
Open AccessArticle
Electrical Propulsion System for Aviation – Experimental Validation of Efficiency Improvements
World Electr. Veh. J. 2012, 5(2), 455-459; https://doi.org/10.3390/wevj5020455 - 29 Jun 2012
Viewed by 215
Abstract
This paper deals with electrical propulsion system for light airplane or paraglider. The electrical drive consists of electrical motor, frequency converter and the batterypack. Electrical motor used in a light paraglider was designed as a permanent magnet synchronous motor (PMSM) in the Research [...] Read more.
This paper deals with electrical propulsion system for light airplane or paraglider. The electrical drive consists of electrical motor, frequency converter and the batterypack. Electrical motor used in a light paraglider was designed as a permanent magnet synchronous motor (PMSM) in the Research and Development Centre of Electrical Machines KOMEL, Poland. Parameters of the motor, frequency converter and battery pack were shown. In this article, an influence of different propellers (1 fixed, 2 adjustable) and results of laboratory test was described. For increasing the efficiency of the electric propulsion, influence of switching frequency of the converter were tested and presented. The results of laboratory test were discussed. Full article
Open AccessArticle
Low-cost FC Stack Concept with Simplified Configuration Utilizing Advanced MEA and FC Module
World Electr. Veh. J. 2012, 5(2), 448-454; https://doi.org/10.3390/wevj5020448 - 29 Jun 2012
Viewed by 287
Abstract
The development of fuel cell vehicles (FCVs) at Nissan proceeded to the level of limited customer leasing with the X-TRAIL FCV equipped with an in-house FC stack (2005- model). Subsequently, a further improved 2008-model FC stack was developed with double the power density [...] Read more.
The development of fuel cell vehicles (FCVs) at Nissan proceeded to the level of limited customer leasing with the X-TRAIL FCV equipped with an in-house FC stack (2005- model). Subsequently, a further improved 2008-model FC stack was developed with double the power density and using only half the amount of precious-metal catalysts, thus giving the vehicle subzero startability at -20°C. For the coming stage of FCV commercialization, we have proposed the concept of a compact and low-cost FC stack (2011 model) that increases the maximum power density to 2.5 kW/L and reduces the estimated production cost to a level that comes very close to meeting the target of the DOE Hydrogen Program for the adoption of 2010 technologies. These advances were achieved mainly by improving membrane electrode assembly (MEA) performance and simplifying the FC stack structure. This paper presents an overview of the simplified structure of the new FC stack incorporating various new features: a shell-enclosed FC module and simplified configuration. This remarkable evolution of the FC stack structure was brought about by the development of various technologies: an advanced MEA, an adhesive seal, and a fastening enclosure. The advanced MEA has an integrated molded frame around it to reduce the production cost. Another benefit of the advanced MEA is the ability to build a stiff insulating shell around a FC module when the frames are bonded together with adhesive seals to form the module. As a result, the FC module can be fastened directly using steel plates uniquely shaped in both the stacking direction and the direction perpendicular to it, thereby maintaining proper compression to prevent the stacked FC modules from sliding. These improvements reduce the variety of components of the new FC stack by an estimated 75%, thus increasing the maximum power density by 30%, compared with the 2008-model FC stack. Full article
Open AccessArticle
Technology Maturity of Fuel Cell System installed in Mercedes B-Class during the World Drive
World Electr. Veh. J. 2012, 5(2), 437-447; https://doi.org/10.3390/wevj5020437 - 29 Jun 2012
Viewed by 210
Abstract
Fuel cell technology is gaining more public, political and industrial awareness after the success of the Mercedes-Benz World Drive. The B-Class F-Cell is equipped with the Nucellsys fuel cell system and accomplished more than 30,000 km in real world condition over 4 Continents [...] Read more.
Fuel cell technology is gaining more public, political and industrial awareness after the success of the Mercedes-Benz World Drive. The B-Class F-Cell is equipped with the Nucellsys fuel cell system and accomplished more than 30,000 km in real world condition over 4 Continents without failures. Operating temperature from -15°C up to 35°C, altitude of more than 2000m, desert heavy rain, highway and heavy traffic jam were challenging the fuel cell system. The technology maturity has been publically demonstrated and important customer and real use information’s has been collected which will further improve the next generation system. This paper gives an up-date of the fuel cell system technology maturity and the outlook of next generation challenges. Full article
Open AccessArticle
Bi-level Control Scheme for Vehicle-to-Grid Regulation Services
World Electr. Veh. J. 2012, 5(2), 430-446; https://doi.org/10.3390/wevj5020430 - 29 Jun 2012
Viewed by 255
Abstract
This paper presents a control scheme of vehicle-to-grid (V2G) operation for the distribution power grid which integrates renewable generation units. An optimal control algorithm is developed to minimize the total operating cost. The potential for providing frequency regulation when the vehicles are idle [...] Read more.
This paper presents a control scheme of vehicle-to-grid (V2G) operation for the distribution power grid which integrates renewable generation units. An optimal control algorithm is developed to minimize the total operating cost. The potential for providing frequency regulation when the vehicles are idle is also analyzed. The power output of plug-in hybrid electric vehicles (PHEVs) is regulated to redistribute the PHEV charging energy and meanwhile provide the grid services. The regulation of PHEV charging load can consume the excessive power from wind generation units during the off-peak time. And with the frequency regulation, the power fluctuation of wind generator can be compensated and therefore stabilize the voltage and frequency. Finally, simulation results verify that the optimal control of V2G power can reduce total operating cost and enhance the voltage stability. Furthermore, the regulation capacity of V2G used for frequency regulation can improve the power quality and facilitate the integration of wind power generators. Full article
Open AccessArticle
Voltage Stability and System Behavior of Cybernetic Loads in Vehicular Power Nets
World Electr. Veh. J. 2012, 5(2), 418-429; https://doi.org/10.3390/wevj5020418 - 29 Jun 2012
Viewed by 222
Abstract
Voltage stability has to be ensured within automotive power buses in order to reliably supply all components with sufficient energy. Especially in modern vehicles (conventional, hybrid electric, or electric), the stability is endangered due to electric loads with high dynamics, for example chassis [...] Read more.
Voltage stability has to be ensured within automotive power buses in order to reliably supply all components with sufficient energy. Especially in modern vehicles (conventional, hybrid electric, or electric), the stability is endangered due to electric loads with high dynamics, for example chassis control systems. In this paper, a power distribution management based on cybernetic principles is described. To manage the power flow efficiently, it is reasonable to distribute some intelligence from the central control unit to the system’s components such as loads. A load’s control algorithm is presented that is able to fulfill the power management functions autonomously. Its stability is examined both in theory and in real cases. Therefore, evaluation criterions are derived from the component’s system behavior. Based on the algorithm’s equations, the transfer function is defined in order to proof the stability. Furthermore, over 200 test cases had been conducted and analyzed at a power net test bench that contains the whole vehicular power net, including wiring harness and chassis ground. The impact of all variables and influence factors on the stability is checked and, likewise, malfunctions are examined, such as measurement errors or data transfer with long dead times. By this means, the most critical variables could be detected. Based on the results, some improvements of the control algorithm are made and, as a result, a stable implementation is realized. Full article
Open AccessArticle
A Behavioral Algorithm for State of Charge Estimation
World Electr. Veh. J. 2012, 5(2), 412-417; https://doi.org/10.3390/wevj5020412 - 29 Jun 2012
Viewed by 252
Abstract
In Hybrid Electricle Vehicles (HEV), performing online energy management is an important task to be achieved to reduce emissions, fuel consumption and increase vehicle performance. For this task, estimating the State of Charge (SOC) is needed since it serves as a measure of [...] Read more.
In Hybrid Electricle Vehicles (HEV), performing online energy management is an important task to be achieved to reduce emissions, fuel consumption and increase vehicle performance. For this task, estimating the State of Charge (SOC) is needed since it serves as a measure of energy that is left inside an electrochemical battery. A variety of methods to solve this estimation problem have been proposed in the literature. However, most of these methods either assume equivalent circuit models for the battery and thus lose their validity under some discharge conditions or depend heavily on the choice of parameters in the algorithm. In this paper, we use behavioral framework to avoid postulation of a specific model for a battery and develop a new and simple SOC estimation algorithm. Once the problem is formulated as the computation of a specific free response of the battery, algorithm computes this response using only terminal current and terminal voltage measurements. We demonstrate the effectiveness of the algorithm with different discharge profiles using both simulated and real data. Full article
Open AccessArticle
Towards Onboard Li-ion Battery State-of-health Diagnosis by a Virtual Sensor
World Electr. Veh. J. 2012, 5(2), 405-411; https://doi.org/10.3390/wevj5020405 - 29 Jun 2012
Cited by 1 | Viewed by 232
Abstract
The development of improved State-of-Health (SoH) diagnosis methods is a current research topic for battery-powered applications. For instance, Hybrid Electric Vehicles (HEV) are in rapid extension and create a strong demand for an accurate and reliable SoH indicator during operation. Such an indicator [...] Read more.
The development of improved State-of-Health (SoH) diagnosis methods is a current research topic for battery-powered applications. For instance, Hybrid Electric Vehicles (HEV) are in rapid extension and create a strong demand for an accurate and reliable SoH indicator during operation. Such an indicator is a key parameter required to optimize battery energy management and to track the degradation of the system performances. Electrochemical impedance spectroscopy is one of the most promising methods for characterizing ageing effects of secondary batteries online because it can be sensitive to different ageing mechanisms. This paper presents a method to measure the electrochemical transfer function of the cell at different frequencies simultaneously with the data treatment of free current and voltage during operation. Impedance parameters were then estimated by a non linear least square algorithm. Based on this approach, an experimental investigation of ageing effects of a lithium ion battery was carried out. After 1400 HEV cycles, the battery showed a 7 % decreased capacity, and 8 % increased resistance at 0.5 Hz. Modelling results show that charge transfer resistance have a similar evolution in function of ageing time than the resistance of battery measured by electrochemical impedance spectroscopy. To our knowledge on the topic, this constitutes a substantial step towards SoH indicator that could be reliable and precise enough under realistic user conditions. Full article
Open AccessArticle
Safety Management for Electric Vehicle Batteries in a Tropic Environment
World Electr. Veh. J. 2012, 5(2), 394-404; https://doi.org/10.3390/wevj5020394 - 29 Jun 2012
Viewed by 248
Abstract
To ensure the safety of a battery system certain measures can be employed. Monitoring the actual battery temperature is crucial to guarantee a safe use of the system while an optimized cooling system for the battery pack helps to improve the liability, prevent [...] Read more.
To ensure the safety of a battery system certain measures can be employed. Monitoring the actual battery temperature is crucial to guarantee a safe use of the system while an optimized cooling system for the battery pack helps to improve the liability, prevent safety shut-os and extend the battery's lifetime. Additionally, possibilities to monitor the state of health of the battery on a longer time scale are necessary to avoid over-stretching the battery's capability of storing energy on the one hand and to reduce investment costs on the other hand. This paper deals with dierent approaches to handle the battery temperature, especially under challenging tropical outside conditions. A temperature distribution model is developed and evaluated using combined data from a sensor matrix and an infrared camera. This method is used for real-time temperature measurements to investigate and monitor the temperature distribution on pouch cells. The simulation of dierent cooling systems is presented to show the need of a steady temperature distribution within a battery pack. The goal is to avoid excessive load on certain cells, which has a high impact on a safe use of the pack and reduces lifetime signicantly. Finally, an approach to characterize the battery thermodynamically is presented. This is expected to be a useful tool to measure and monitor the state of health of a battery and rst investigations are shown for dierent cell chemistries, performed on commercially available full cells. Full article
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