bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Impedance Spectroscopy for Li-Ion Batteries with an IR Temperature Sensor System
Authors: Keil Peter , Rumpf Katharina , Jossen Andreas
Published: May 2018

Thermal impedance spectroscopy (TIS) is a non-destructive method for characterizing thermal properties of entire battery cells. Heat capacity, thermal conductivity and heat exchange with environment are deter-mined by an evaluation of the heat transfer behavior of the battery. TIS measurements are usually conduct-ed with contact-based temperature sensors, such as thermocouples or thermistors, which show drawbacks at higher convection rates and higher temperature differences between battery and environment. To elude drawbacks in these kinds of sensors, an infrared-based temperature sensor system for battery sur-face temperature measurements is implemented. TIS measurements are conducted with this sensor system and with conventional, contact-based temperature sensors. Accuracy and reliability of thermal parameter identification is analyzed for the different sensor systems. Moreover, thermal parameters are identified for different cylindrical 18650 Li-ion cells with capacities between 1.1 Ah and 2.7 Ah. The comparison of different types of temperature sensors shows that contact-based sensors underestimate surface temperatures even at low temperature differences to environment. This causes an error in thermal parameter identification. The TIS measurements performed with contact-based sensors show divergence of 20 - 60 % for heat capacity, 30 - 70 % for thermal conductivity and 20 - 60 % for convective heat exchange with environment. With our IR temperature sensor system, parameter identification is performed for different batteries. Re-sulting values for specific heat capacity are in a range between 900 and 1020 J/kgK and thermal conduc-tivities in radial direction lies between 3.1 and 3.6 W/mK. Our investigations show that IR-based temperature sensors are an effective progression for TIS measure-ments and improve quality of parameter identification at low cost. Moreover, discrepancies mentioned in TIS literature can be explained by our findings.
Energy Storage Systems for Electric Vehicles: Performance Comparison based on a Simple Equivalent Circuit and Experimental Tests
Authors: Concha P. , Lafoz M. , Vélez P. , Arribas J. R.
Published: May 2018

The decision to select the most suitable type of energy storage system for an electric vehicle is always difficult, since many conditionings must be taken into account. Sometimes, this study can be made by means of complex mathematical models which represent the behavior of a battery, ultracapacitor or some other devices. However, these models are usually too dependent on parameters that are not easily available, which usually results in nonrealistic results. Besides, the more accurate the model, the more specific it needs to be, which becomes an issue when comparing systems of different nature. This paper proposes a practical methodology to compare different energy storage technologies. This is done by means of a linear approach of an equivalent circuit based on laboratory tests. Via these tests, the internal resistance and the self-discharge rate are evaluated, making it possible to compare different energy storage systems regardless their technology. Rather simple testing equipment is sufficient to give a comparative idea of the differences between each system, concerning issues such as efficiency, heating and self-discharge, when operating under a certain scenario. The proposed methodology is applied to four energy storage systems of different nature for the sake of illustration.
Lithium-ion Battery Electro-thermal Model and Its Application in the Numerical Simulation of Short Circuit Experiment
Authors: Lin Chengtao , Cui Can , Xu Xiaotian
Published: May 2018

As a key issue in EVs (Electric Vehicles) development, Li-ion battery’s thermal safety is focused on in which the thermal abuse model is an important tool. This paper has established a 3-D electro-thermal model taking side reaction into account, in order to study on MGL100Ah lithium manganite battery’s safety issue. This paper firstly states the mechanism of heat generation, types of thermal model, and the mesh model, then analyzes the simulation on the model under the short circuit condition, one of thermal abuse condition. On one hand, the paper verifies the liability of the model, so as to apply the model on other thermal abuse condition in the future; on the other hand, the paper discusses in detail the internal temperature distribution, voltage and current changes under the short circuit condition. Analyzing this typical safety issue in details, this paper can help reduce cost, raise design efficiency and avoid thermal abuse in future development of battery.
Research on Simplification of Simulating the Heat Conduction in the Lithium-ion Battery Core
Authors: FENG Xuning , HE Xiangming , LU Languang , OUYANG Minggao
Published: May 2018

This paper discusses the model simplifing issue in battery thermal simulation. The paper verifies that for the large power battery simplifying the multilayer battery core as a lumped cuboid is reasonable. So when doing simulation, building a multilayer core is unnecessary. And the calculation cost can be reduced by the lumped model. Specific power battetry of 70Ah is dissembled to be modeld. Thermal models of are established, including models with a lumped core and with multilayer cores. For the lumped core, the anisotropic thermal conductivities are got by equations calculating series and parallel equivalent thermal conductivity. While for the multilayer core models, the core contains numbers of unit cells and the volume of which is equal to that of the lumped. In addition, under the boundary conditions of inner heat source and surface heating, steady state simulations are performed. Simulation results indicate that the temperature distributions of the lumped model and the multilayer model are almost the same. For one thing, large number of multilayers and low shell thermal conductivity contribute to a uniform temperature distribution within the core, so it is reasonable to simplify the multilayer core as a lumped cuboid. For another, due to the size of the battery and the shell property, it is difficult to find a simple curve to fit the simulation temperature on the battery surface. Although minor differences still exist, the lumped core can well subsitute the multilayer core in battery thermal simulation.
Modelling of Li-ion Batteries Dynamics using Impedance Spectroscopy and Pulse Fitting: EVs Application
Authors: Pérez G. , Gandiaga I. , Garmendia M. , Reynaud J.F. , Viscarret U.
Published: May 2018

One of the most relevant tasks that must be carried out by a Battery Management System (BMS) is the diagnosis of the battery state. An important part of the algorithms used for determining the State of Charge (SOC) or the State of Health (SOH) requires a cell model to run. The most precise is the model used, the best is the estimation achieved by the algorithm. In this paper, two techniques for obtaining a model of the cell dynamics and calculating its parameters are analyzed: the time domain characterization and the frequency domain or impedance-based characterization. Their principal characteristics and some relevant considerations to take into account are explained, as well as the obtained results. The performance of both models is compared in terms of the voltage error and the requirements to use them. Finally, a combined methodology is proposed to overcome the problems which can appear when each technique is employed. The resultant model is validated at 25 ºC in all SOC range using real measurements of a 40 Ah Li-ion cell with different current profiles, including pulses of diverse lengths and FUDS driving cycles. The tests show small error between the real response of the cell and the output of the model.
Mechanically actuated variable flux IPMSM for EV and HEV applications
Authors: Urquhart I. , Tanaka D. , Owen R. , Zhu Z.Q. , Wang J.B , Stone D.A
Published: May 2018

The current trend in production EVs/HEVs is to use interior permanent magnet synchronous motors (IPMSM) as the means of providing power to the vehicle drive train. The efficiency of these machines can be extremely high (>95%) although this typically occurs in a relatively narrow range in the middle of the machine speed-torque curve. This is a concern for automotive applications as vehicles operate across the full range of speeds and torques; typical urban drive cycles operate in the low speed/torque region where efficiencies can drop to below 80%. Clearly there is a mismatch between the region of high efficiency of the machine and the region of highest operation duty of EVs/HEVs. This paper presents a method of expanding the peak efficiency region of the machine by introducing a method for adjusting the permanent magnet flux linkage utilising a mechanism that short circuits the flux at the end caps of the rotor using solid steel plates. These plates are operated such that they can switch between open and closed positions depending on the demand on the machine allowing the flux linkage to be varied. Analysis shows that by applying the plates to short the flux in the rotor the flux linkage in low torque/high speed applications is lowered whilst reducing the need for high flux weakening currents in the d-axis. This reduces current consumption, improving the power factor and therefore increases the overall efficiency of the machine. The performance of the system is verified using a proof of concept IPMSM.
Iterative capacity estimation of LiFePO4 cell over the lifecycle based on SoC estimation correction
Authors: Macicior H. , Oyarbide M. , Miguel O. , Cantero I. , Canales J.M. , Etxeberria A.
Published: May 2018

Real time state of charge (SoC) and state of health (SoH) monitoring plays an essential role in electric vehicles, hybrid electric vehicles and generally in battery powered applications. Between these two state estimations, only the SoC has been studied rigorously until the current dates, while SoH or capacity estimation are much less referenced on the literature. Additionally, the SoC and the SoH estimation are strongly correlated by widely used coulomb counting equation and consequently wrong capacity estimation would lead to a SoC estimation error, which in turn, will lead to a further capacity estimation error. In this sense, the first job was to develop the equivalent electric model, design SoC estimator and to verify both of them experimentally. Then, different alternative techniques for estimating the capacity are analyzed, selecting the best choice considering the observability degree of the object of estimation: capacity. Then, in this paper we propose a new method for estimating the capacity, called iterative transferred charge, which adapts the current capacity estimation value based on the SoC correction made by the corresponding estimator. Finally, the developed algorithm is evaluated by comparing the capacity estimation with the reference over the life of the cell, by extensive experimental tests.
Fast Charging Method Based on Estimation of Ion Concentrations using a Reduced Order of Electrochemical Thermal Model for Lithium Ion Polymer Battery
Authors: Choe Song-Yul , Li Xueyan , Xiao Meng
Published: May 2018

Comparably long charging time for battery of electric and hybrid vehicles is one of barriers for massive commercialization of the vehicles. Typical charging methods are by a constant current (CC) with constant voltage (CV), pulsed or tapered current. Theoretically, the charging time can be reduced by increased amplitude of the charging current, which, however, accelerate degradation of cells and reduces the lifespan. The relationship between the charging current and the degradation has not been well understood. Studies on ion transport and chemical reactions using a computational model developed in our laboratory reveal that a high charging current causes excessive ions at the surface of electrode particles because of slow diffusion process of ions in the solid electrodes. The excessive lithium ions react with electrons and form a thin layer, called Lithium plating that is irreversible. The Lithium plating not only reduces ion conductivities, but also contributes growth of dendrites and potentially internal short circuit. In this paper, a new charging algorithm is proposed that is based on an electrochemical and thermal model, which order is drastically reduced in order to facilitate a real time operation. The model, called Reduced Order of Electrochemical Thermal Model (ROM), is completely validated with a pouch type of Lithium polymer battery and used to dynamically estimate ion concentration at the surface of particles. Based on the estimated ion concentration, a new control algorithm is derived that allows for determination of amplitude and duration of the charging current. The ROM performs at least ten fold faster in calculations than the original full order model. The simulation and experimental results show that the charging time can be reduced to 60-70% of that of the classical CC/CV charging by preventing excessive ions and slowing down degradation of cell capacity losses.
Using on-board Electrochemical Impedance Spectroscopy in Battery Management Systems
Authors: Christensen Andreas , Adebusuyi Adetunji
Published: May 2018

As the need for better prediction of battery life parameters in secondary batteries evolves, especially for electric vehicles, many researchers have looked for methods beyond simple battery modeling. One of the promising methods is electrochemical impedance spectroscopy. This is typically a technique used to get insight on the kinetic reactions in batteries and various studies have shown excellent correlation between impedance data and the state of health and ageing effects in lithium-ion batteries. In this article the benefits of using electrochemical impedance spectroscopy in battery management systems will be studied as it has been shown by multiple researchers that it is possible to develop an embedded electrochemical impedance spectroscopy circuit. The accuracy of currently available models based on impedance data deteriorates over time and to enable a battery management system to keep accurate predictions on state of health and other ageing-related effects there is a need for on-board electrochemical impedance measurements. Aspects such as SoH, balancing, battery ageing, and second life is discussed in relation to electrochemical impedance spectroscopy and battery management systems.
Global Service Provider for Electric Vehicle Roaming
Authors: Ratej Jure , Mehle Borut , Kocbek Miha
Published: May 2018

Due to the rising number of electromobility business entities (electric vehicle supply equipment operators and electromobility service providers), electric vehicle users are faced with a growing complexity in the use of public charging infrastructure, especially on a greater geographical scale. The development of electromobility calls for interoperability between all electromobility entities in order to enable roaming of EV users and remove the present barriers in EV users’ access to the public charging infrastructure. The paper describes the elementary processes related to EV charging (charging, reservation of charging spot, billing of charging service fee), the roles of electromobility entities in these processes, and their importance for the development of the roaming system. ETREL has developed an integrated roaming solution introducing a new entity, the global service provider, which mediates between the electromobility entities to enable roaming. The paper discusses the architecture and functionalities of the roaming scheme which comprises the global service provider. The paper also describes individual elements of the global service provider’s ICT system. The EV charging processes are explained again, this time in relation to roaming and with a focus on global service provider’s role in the processes. The final section of the paper proposes further steps to expand the roaming scheme functionalities and its geographical scope, where standardization or at least an agreement on ICT interfaces, application level protocols, and software services plays the key role.
How well can early adopters of electric vehicles be identified?
Authors: Plötz Patrick , Gnann Till
Published: May 2018

Electric vehicles have recently been introduced to market in Europe. Policy makers as well as car manufacturers have great interest to understand the first group of electric vehicle users, the so-called ‘early adopters’. Several studies have tried to determine the potential early adopters of electric vehicles from different angles. However, the number of available studies is limited and little is known about the actual statistical significance of characteristics for this important user group. Here we characterize the potential first users of electric vehicles from an economic perspective and ask which driving profiles make an electric vehicle cost-effective. To this end, we analyze a large database of German driving profiles and find the share of potential first users from different city sizes and statuses of employment. We first find the potential and in a second step study the statistical significance and robustness of the result by (1) performing Chi-square tests of the differences between potential early adopters and other vehicle owners and (2) varying important input parameters of our estimates. We find our characterization of the early adopters to be robust if battery prices and consumption costs are sufficiently favorable for a not too small group of users.
GPS measurement of Swedish car movements for assessment of possible electrification
Authors: Karlsson Sten , Kullingsjö Lars-Henrik
Published: May 2018

To enhance the transition to electrified vehicles, such as PHEVs, the use patterns of cars need to be well understood and thus information about individual vehicle’s movements over longer time periods is needed. This is of major importance for instance for optimal powertrain and battery design, estimation of consumer viability and potential for PHEVs and for assessment of policies for shifting energy use in transport sector from fuel to electricity. Good and publicly available data of this kind is today unfortunately lacking. The aim of this project has been to gather a larger amount of data on the characteristics and distribution of individual movements for privately driven cars in Sweden by measurement with GPS equipment. The logging was performed with commercial equipment containing a GPS unit, including a roof-mounted antenna, and a gprs communication unit. Data logged (2.5 Hz) were: time, position, velocity, and number and id of used satellites. The measurements started in June 2010 and ended in September 2012. The target has been to accomplish good quality measurements of at least 30 days for about 500 representative vehicles. The paper includes a description of the project, an analysis of its representativeness and some car movement statistics for the full results.
Lessons Learned from the Danish EV Living Lab
Authors: Agerskov Mai Louise , Høj Jens Christian Lodberg
Published: May 2018

The success of EVs in the marketplace will highly depend on the end-user acceptance. Insero E-Mobility has examined the user acceptance of EVs through a living lab study, where 80 Danish families used EVs for a period of 8-10 weeks as their only car. The study included a general test and identification of problems faced during usage as well as positive features of the EVs. Fleet potentials were additionally investigated with two trials in departments in Danish municipalities for 14 days. The living lab approach was used to reveal actual and latent needs as well as to facilitate innovation processes with the purpose of rendering input for product and business model development that will increase chance of end-user acceptance of EVs in the future. Long term public user trials has also in the case of the Danish EV Living Lab proven to provide comprehensive and rich amount of information on end customer needs and perceptions that can be used to define value across a range of attributes considered in vehicle purchasing decisions. Key conclusions are that 90% of families found that an EV could fulfil their demands but that range is an important issue even though it is mostly a psychological barrier. For fleets the EVs make sense to an extent depending on the predictability of driving behaviour and available infrastructure.
Promotion of Freight Mobility in Milan: Environmental, Energy and Economical Aspects
Authors: Menga P. , Buccianti R. , Bedogni M. , Moroni S.
Published: May 2018

In order to improve air quality in the Controlled Traffic Zone “Area C” of Milan, in addition to the rules already in force, two topics now under consideration by the municipality are the increase of car-sharing and measures to stimulate the use of electric vehicles, including their adoption for the last-mile delivery of goods. The paper presents the evaluation of the potential benefits of electric vehicles, in particular for the case of goods delivery. Comparisons to present i.c.e. based vehicles are presented in terms of economical aspects (from the point of view of the end user and of the Country), energy consumption and pollution impact (both local and global). Also the contribution to costs and pollution of two-wheels motor vehicles is taken into consideration in order to give a more complete overview of the different traffic segments.
The Recycling Efficiency of Li-ion EV batteries according to the European Commission Regulation, and the relation with the End-of-Life Vehicles Directive recycling rate
Authors: Tytgat Jan
Published: May 2018

In Europe, batteries from electric vehicles are subject to the EC Directive 2006/66/EC (Batteries Directive). This Directive regulates the end-of-life management and sets targets on the recycling efficiency. The concept of battery recycling efficiency goes beyond the recycling target of the End-of-Life Vehicles directive. The paper describes the meaning of the recycling efficiency and illustrates how it is calculated in the case of Li-ion battery recycling according to the Umicore battery recycling process.
California’s ZEV Action Plan
Authors: Chiladakis Lisa , Crowfoot Wade , Winston Randall
Published: May 2018

Accelerating the market for zero-emission vehicles (ZEVs) is a cornerstone of California’s long-term transportation strategy to reduce localized pollution and greenhouse gas emissions, save consumers money, and enable continued economic growth. In addition to promoting these vehicle technologies, the state supports the development and use of low carbon fuels, as well as planning more environmentally sustainable communities that reduce unnecessary vehicle travel and congestion. In March 2012 Governor Brown signed an Executive Order calling for 1.5 million ZEVs by 2025. To identify specific actions that the State can take to reach this goal, the Governor’s Office with the input from a Governor’s Office Interagency Working Group developed the 2013 ZEV Action Plan.
Communication Solutions for a Cloud-Based Charging Management System for a Fleet of Shared-Use Electric Vehicles
Authors: Mierau Michael , Fey Simon , Kohrs Robert , Wittwer Christof
Published: May 2018

The paper proposes a system architecture for charging infrastructure that serves the requirements of future fleets of shared-use electric vehicles in urban scenarios. The focus of the development is on the interfaces to central stakeholders such as mobility service providers, distribution network operators and utilities. The main concept of the proposed system is the adherence to a stringent resource-oriented design approach, following the design principles of the Representational State Transfer (REST) architectural software style for distributed systems. This design approach is used from the cloud-based services down to the implementation of the charging infrastructure’s control algorithms. Focusing on the resources of the various entities simplifies the implementation of their interactions, compared to the explicit declaration of services that are available. The system design ensures that the charging infrastructure is open to all users and generates a benefit beyond basic charging operations. Integration in emerging smart markets is done via open web-based interfaces. These allow for the generation of an added value of concrete services for shared-use electric mobility. A link to the field of grid operation is proposed using the ISO/IEC 61850 telecontrol standard. The smart meter capabilities of the charging stations can be used to gain additional information on the current state of the distribution grid. As an exemplary service a load management service for a fleet of shared-use electric vehicles is going to be implemented.
Thermal Model Developments for Electrified Vehicles
Authors: Kim Namwook , Kim Namdoo , Rousseau Aymeric
Published: May 2018

Argonne National Laboratory has analyzed the control behavior of advanced vehicles, such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs), to develop simulation models and to reproduce the performance of vehicles with simulation techniques. Since many of the novel and advanced studies about transportation technologies done at Argonne use these simulation techniques, they must be well-validated to conduct and support these studies. To improve its research ability, Argonne built a new testing facility that can test vehicles under different thermal conditions (e.g., –7°C or 35°C), and it has analyzed the controls and performance of several advanced vehicles under these conditions. Further, Argonne has used the analyzed results to develop thermal component models that reproduce the thermal behavior of the vehicles. A main reason to develop thermal models is that the thermal conditions have such a significantly large impact on vehicle performance, especially with regard to advanced vehicles like HEVs or PHEVs. For instance, engine and battery efficiencies must decrease at low temperatures since the battery might not be able to provide enough power if it is very cold. Moreover, the climate control system still has a great demand for additional energy under very cold weather conditions even if the engine is not operating at all. The test data obtained from Argonne’s Advanced Powertrain Research Facility (APRF) are analyzed in order to understand the thermal impacts on controls and performance, and the thermal models are developed based on the analyzed results and validated with the test data. In comparative studies, the simulation models have been found to reproduce fuel consumption that is very close to the fuel consumption obtained from the tests.
Modelling and Simulation Study on a Series-parallel Hybrid Electric Vehicle
Authors: Li Yaohua , Wang Ying , Zhao Xuan
Published: May 2018

Hybrid electric vehicle (HEV) uses internal combustion engine (ICE) and electrical power, so it has the advantages of both ICE vehicle and electrical vehicle (EV) and overcomes their disadvantages. And seriesparallel hybrid is the combination of series and parallel structures, thus it possesses the major features of both and more plentiful operation modes than one of them alone. In this paper, a series-parallel HEV model is built by using Matlab/Simlunk, which constitutes of vehicle longitudinal dynamics model, tire model, an ICE model, battery model, a DC/DC converter model, a motor drive model, a generator drive model, a speed coupling device model (planetary gear mechanism), and a torque coupler device model. Control scheme of HEV is presented. And Simulation results testify the effectiveness of the HEV model.
Design of a Novel SiC MOSFET Structure for EV Inverter Efficiency Improvement
Authors: Jung Young-Kyun , Lee Jong-Seok , Lim Taewon
Published: May 2018

Inverters for electric vehicle motor drive systems are essential in converting the battery's direct current into alternating current. Si(Silicon) IGBT that is commonly used in inverter modules have large Vce,sat and turn-off time due to p+ drain and tail current. Therefore, inverter modules consist of Si IGBT with relatively low efficiency. If we can use MOSFETs instead of IGBT in inverter modules, it is possible to achieve high efficiency because of short turn-off time and high operating frequency. Yet also has a problem; Si MOSFETs has large on-resistance compared to Si IGBTs. In this study, SiC(Silicon Carbide) was used to make MOSFETs instead of Si. Futhermore, an accumulation channel concept is adapted to a SiC trench MOSFET, namely Trench ACCUFET. Compared with conventional SiC trench MOSFETs, the novel SiC trench ACCUFET structure has not only lower on-resistance but also high breakdown voltage as shown by the simulation results. We fabricated the Trench ACCUFET for verification, and described improvements that is to be made.
Robust Control Method of Induction Machine against Temperature Variation
Authors: Kim Sang , Kim Hyeong , Kwon Taesuk
Published: May 2018

This paper proposes a control method robust against the rotor temperature variation for the induction machine used in the xEV traction application. The rotor resistance (or time constant) of the induction machine varies with the rotor temperature so that its torque control performance will be degraded if this variation is not properly compensated. In this paper, firstly a direct vector control method, which is based on the rotor flux estimator using the current model in the synchronous reference frame, is adopted in order to control the DQ-axis rotor fluxes independently. Secondly, the rotor time constant variation is compensated utilizing the flux estimation difference between the voltage and current models. This method has no transition region which is inevitable in the conventional method that uses the current model in the low speed region and the voltage model in the high speed range for estimating the rotor flux. The robustness to the temperature change of the proposed method is validated through the experiment in the motoring and regeneration modes.
Using multiobjective optimization for automotive component sizing
Authors: Vijayagopal R. , Chen R. , Sharer P. , Wild S.M. , Rousseau A.
Published: May 2018

This paper shows how a multiobjective problem is formulated and solved in order to size the components of a vehicle with a split hybrid transmission, such as a Toyota Prius. The goal is to explore feasible design options and the trade-offs between fuel economy and vehicle cost. Eight input variables are provided for this optimization, including plant variables such as maximum power ratings for engine, motors, and battery; final drive ratio; and control variables that determine how the battery energy is utilized. Three constraints are used: achievement of the battery charge balance, ability to trace the drive cycle, and ability to achieve a zero to 60 mph acceleration performance within 10 seconds. We describe a multiobjective optimization algorithm that we have implemented in Autonomie, a simulation tool developed at Argonne, and we demonstrate its ability to utilize parallel computing capabilities of Matlab. A parallel/distributed-computing infrastructure is used to simultaneously evaluate multiple combinations of input parameters, over multiple drive cycles, thereby reducing the overall time taken to perform the optimization and hence reduce the total solution time. The optimization produces several design choices, which form a Pareto front. The search algorithm ensures that as the number of iterations increases, more and more points are added on or near the Pareto front. All the points that form the front are relevant design choices, and the front characterizes the balance between conflicting goals such as fuel economy and performance.
Cooperative Control Algorithm for Friction and Regenerative Braking Systems Considering Temperature Characteristics
Authors: Kwon Minho , Park Jinhyun , Gwak GiSung , Huh Jeewook , Hwang Sung-Ho
Published: May 2018

In a hybrid electric vehicle (HEV), the braking system is composed of friction braking and regenerative braking. When a driver presses the brake pedal, each braking system collaborates and applies braking torque. The friction brake is a hydraulic system which has a slow response time and the regenerative brake is an electric system which responds quickly. Such characteristics bring a control problem, especially transient characteristic of shifts between regenerative brake and friction brake, because the hydraulic system cannot follow the response time of the electric system. The friction braking torque is also governed by the friction coefficient which changes with temperature. This causes the braking torque to be generated differently with the demanded braking torque, without considering the temperature. Due to these problems, the driver would feel uncomfortable and the vehicle would be unstable resulting from the difference in response time and variance of the friction coefficient when pressing the brake pedal. Hence, it is essential to coincide the settling time of friction and regenerative braking system regarding the temperature. To solve these problems, the hydraulic system was mathematically modelled using the flow and continuity equations and the electric system was modelled using the d-q transformation and voltage equation. The temperature estimation model of the brake components was developed using the heat transfer methods which are conduction, convection and semi-infinite solid. The brake temperature was calculated by the finite difference method (FDM). With the mathematical model of hydraulic and electric systems, the coincidence control for the settling time of both systems was established. It was also possible to find the friction coefficient and calculate the braking torque by using the temperature estimator. In this paper, the numerical simulation was carried out to verify these control algorithms. The difference in response time between friction and regenerative braking system was reduced and the transient characteristic was improved. Also, the braking torque was compensated with the temperature, and the difference between demanded and actual braking torque lessen using the algorithms.
A Stochastic Model Predictive Control Strategy for Energy Management of Series PHEV
Authors: Xie Haiming , Chen Hongxu , Tian Guangyu , Wang Jing
Published: May 2018

Splitting power is a tricky problem for series plug-in hybrid electric vehicles (SPHEVs) for the multi-working modes of powertrain and the hard prediction of future power request of the vehicle. In this work, we present a methodology for splitting power for a battery pack and an auxiliary power unit (APU) in SPHEVs. The key steps in this methodology are (a) developing a hybrid automaton (HA) model to capture the power flows among the battery pack, the APU and a drive motor (b) forecasting a power request sequence through a Markov prediction model and the maximum likeli-hood estimation approach (c) formulating a constraint stochastic optimal control problem to minimize fuel consumption and at the same time guarantee the dynamic performance of the vehicle (d) solving the optimal control problem using the model predictive control technique and the YALMIP toolbox. Our simulation experimental results show that with our stochastic model predictive control strategy a series plug-in hybrid electric vehicle can save 1.544 L gasoline per 100 kilometers compared to another existing power splitting strategy.
System-on-Chip-based highly integrated Powertrain Control Unit for next-generation Electric Vehicles: harnessing the potential of Hybrid Embedded Platforms for Advanced Model-Based Control Algorithms
Authors: Dendaluce M.
Published: May 2018

In this paper, a novel highly integrated System on Chip (SoC) based control unit concept is presented, which is conceived to combine the functionality of various powertrain ECUs and to additionally enhance their control with predictions based on the real-time execution of complex mathematical models. Such a platform has the potential for providing considerable benefits to upcoming hybrid and electric vehicles, especially for highly complex and efficient hybrid and multi-motor electric vehicles. A clear advantage is the reduction of Control Units, consequently also reducing the system complexity, communication requirements and development effort, which are directly associated to production and development costs. A controller architecture capable of exploiting the strength intrinsic to the nature of each platform type is presented, basing on the new generation of high-performance hybrid SoC platforms which combine powerful processors with cutting edge FPGAs. The parallel hardware paradigm of FPGAs enables the implementation into a single component not only of several Field Oriented Control loops for electrical motors, power management functions and vehicle-level optimizations, but also of advanced real-time predictive algorithms. The combination of so many complex tasks would not be feasible on a typical automotive microcontroller unit. A further objective for obtaining a highly integrated solution is to establish an efficient development and prototyping process, aiming to simplify and harmonize the workflow through the whole V model, by completely basing it on model-based-design tools. Finally, the concept demonstrator being implemented in this paper will combine a state-of-the-art high performance microprocessor and FPGA using a commercial SoC platform together with model-based software development tools. This will also fulfil the expectation of providing a topology with great migration and industrialization potential for the case of higher qualification requirements. Furthermore, it is another step towards a necessary mindset shift on control system development and integration methods for increasingly complex vehicles.
Analysis of field-stressed modules from a fuel-cell vehicle’s main inverter
Authors: Heo Hye-Seong , Pannemann Christoph , Choi Yun-Kyu , Castro Carlos , Strass Achim
Published: May 2018

This paper presents a reliability study of a directly cooled and an indirectly cooled IGBT module after a test drive of 85.000 Km in a fuel cell electric vehicle. In this case, the car was mainly driven on highway, only a minor part of the distance was driven in urban areas. At the end of the test drive, the power control unit was disassembled and analyzed with regard to the lifetime consumption. First, electrical measurements were carried out and the results were compared with the ones obtained directly after module production (End of Line test). After that, ultrasonic microscopy was performed in order to investigate any delamination in the solder layers. As a third step, an optical inspection was performed to monitor damages in the housing, formation of cracks or degradation of wire bonds. The results show none of the depicted failure modes could be found on the tested power modules after the field test. Obviously, no significant life time consumption could be observed.
Promotion Strategy of Low-Speed Electric Trucks for Wholesale Markets in Taiwan
Authors: Chu Kao-Hone , Gau Tien-Ho
Published: May 2018

Xiluo produce market is the largest wholesale market which supplies one-third fruit and vegetable demand in Taiwan. However, each day more than 800 diesel-powered tricycles running at the market result in serious air and noise pollution. In order to solve the pollution problem, since 2010, the Environment Protection Administration (EPA) has implemented a plan to replace the diesel-powered tricycles with electric trucks. Besides, EPA also integrates efforts with local manufactures to develop appropriate electric trucks which can accommodate the requirements of usage. On July 3, 2013, EPA further announced a subsidization program, namely "the Regulations Covering Subsidies for Electric Produce Transporters at Xiluo Produce Market". According to the program, the subsidy covers the purchasing cost of electric trucks (excluding battery) and rental fees of the power batteries. At the same time, a battery management operator will be selected to provide service of maintaining battery. In addition, EPA drew up the verification specification as the vehicles' testing standard to ensure the function and safety of the electric trucks. The target is to eliminate all diesel-powered tricycles out of the Xiluo produce market before 2018 and the air quality improvement is in line with Taiwan's indoor air quality standards. Taiwan's government hopes to electrify all diesel vehicles currently in the other similar wholesale markets basing on the experience of promotion, so as to build clean trading environment for all wholesale markets in the future. This paper will discuss this vehicle electrification case study in detail and share the experience.
EV Motor Controller Target Cooling by Using Micro Thermoelectric Cooler
Authors: Lin Frank , Chang Po-Hua , Hwang Chih-Yu , Wu Min-Chuan , Chen Yi-Shin
Published: May 2018

The motor controller is an important component in electric vehicle. Controller always generates heat and needs cooling as electric vehicle driving. Micro thermoelectric cooler (μTEC) with many advantages becomes a potential cooling device for controller recently. This study uses the commercial software ANSYS workbench 14.5 to investigate the influence of the activated number and located position of μTEC on controller chip cooling. The following simulation results are obtained: (1) μTEC activating may assist cooling between 0 second and 60 seconds. The cooling capability enhancement is pronounced as the number of activated μTEC increased. (2) μTEC activating may not assist cooling between 60 seconds and 156 seconds because the energy on the hot side of μTEC is unable to be removed effectively. “All μTEC open” method gives the poorest cooling performance in this region.
Electric Vehicle Energy Consumption Modelling and Prediction Based on Road Information
Authors: Wang Jiquan , Besselink Igo , Nijmeijer Henk
Published: May 2018

The limited driving range is considered as a significant barrier to the spread of electric vehicles. One effective method to reduce “range anxiety” is to offer accurate information to the driver on the remaining driving range. However, the energy consumption during driving is largely determined by driving behaviour, road topography information and traffic situation, which are hard to predict. This paper will discuss an accurate electric vehicle energy consumption model validated using driving tests on different public roads, and then the model is used to predict future energy consumption based on road information. The energy consumption model includes five parts: the road load model, the powertrain loss model, the regenerative braking model, the auxiliary system model and the battery model. The parameters of these models are obtained through driving tests on public road and dynamometer tests in the TU/e Automotive Engineering Science lab. The results show that the model can calculate the energy consumption with a maximum error of 5% based on driving speed under different circumstances. To predict the future energy consumption, the road information is obtained from OpenStreetMap and Shuttle Radar Topography Mission. An offline algorithm is built to predict the energy consumption for a future trip based on the road information. The algorithm gives two energy consumption results: one is for the fastest driving speed; the other one is for the most economic driving speed. The results show that the measured energy consumption results for different types of road driving are all within the algorithm’s prediction scope. Therefore, the offline algorithm can give an accurate energy consumption estimation to the driver before a trip begins.
Coupling local renewable energy production with electric vehicle charging: a survey of the French case
Authors: Codani P. , Portz P-L. , Claverie P , Perez Y. , Petit M.
Published: May 2018

The share of renewable energy sources (RES)’ production in energy mixes, especially the ones of PV panels and wind farms, has been continuously increasing during the last few years. Similarly, a strong development of battery electric vehicles (EV) is expected within the next years. However, these two new innovations could trigger security issues on electrical grids, in particular local congestions and voltage deviations from the required standards. One way to mitigate these problems could be to combine the charging periods of the EVs with the local RES production. This paper aims at analysing the possibility to implement this kind of smart charging strategy in France by 2020, taking into account the wide diversity of local energy mixes in France and their seasonal dependencies. First, the authors identify four different energy mixes representative of most of the local French mixes, each one related to a region in France. Then, we model the charging load curves of the EVs at the substation level for the same regions. We deduce the “green charging ratio” (GCR) without any charging management strategy. The same ratio is then computed assuming that an Energy Management System (EMS), which goal is to maximize this ratio, controls the EV charging patterns. The results are provided for each region and seasons. They show a wide diversity of green charging ratio achievable: in very windy regions, the GCR without any EMS is already rather high; on the contrary, in sunny regions, the GCR is much improved with the implementation of the EMS. In such regions, the GCR can also be enhanced with the penetration of charging stations at working places.
DC Quick Charging Operation Assistant Development and Experiment in Taiwan
Authors: Chen Sheng Hua , Lin Hung Hsi , Hsu Kai Ping , Hsu Hsiao Yu , Lin Chih Hung , Fang Ming En , Liao Ying Chao , Chou Shean Kwang , Chung FengYeang
Published: May 2018

Electric Vehicle is widely used in passenger service gradually. It is a critical successful factor to have a sufficient electric energy supply. In order to solve the constraint of economical issue, the fast charging method can decrease the charging time such that the service time can be extended without dramatically increasing the battery numbers. This research develops a fast charging system which follows international regulation. The fast charging system includes a charging station simulation system, a battery loading simulation system, and a charging controller mounted on a fast charging vehicle. This system has completed connection tests with charging stations of ABB from Europe and Delta in Taiwan and also finished system verification with Japan HASETEC, which is a major company involving in CHAdeMO association affair. The developing charging controller undergoes several charging/discharging experiments for marine high capacity lithium ion battery module. The cells of the battery module still maintain reasonable balance status after charging process, which proves the developed charging controller of this research can safely and efficiently fast charge a lithium battery module via high voltage direct current. It is the goal for this research that promote adopting electric boat in touring water field for carbon emission reduction and water resource protection can be realized all at once.